Methods and apparatus for selecting between multiple carriers based on signal energy measurements

The present invention relates to communication systems, and more specifically, the present invention is to determine the availability of carriers, to select carriers and / or, for example, one network connection point associated with one carrier. Directed from, for example, methods and devices for determining when to initiate a handoff to another network connection point associated with another carrier.

From the point of view of means of execution, it may be advantageous to use different carriers in different parts of the communication system, eg, because rights to different frequencies are owned in different geographic locations and / or. This is desirable to minimize signal interference through users of different carriers. Spectral diffusion wireless communication systems can use different carriers throughout the system with each carrier associated with a different frequency band. In some wireless communication systems, different cells and / or sectors use different carriers. In one system, the same sector or the same cell uses different carriers, each with a related frequency band, eg, where the overall bandwidth available in the cell or sector is different. It is divided into frequency bands, for example, multiple separate frequency bands.

Wireless terminal (WT: wireless) terminal), for example, a mobile node can travel the entire communication system and a given sector / cell that uses the associated band for connectivity with a particular carrier frequency and, for example, downlink signaling. A connection with the base station can be established. For example, a change in loading state at a carrier frequency, eg, for more users, due to a change in the level of interference, or for a WT move, eg, for approaching a cell / sector boundary. As it varies, it may be advantageous or necessary for the WT to switch to another carrier and connect to another cell / sector / carrier frequency corresponding to the base station transmitter. Generally, in known systems, multiple wireless terminal receiver execution means use a single receiver chain, and the wireless terminal is the same carrier until, for example, forced to switch due to interruption of communication by a base station. Stay on top. This approach is undesirable because the WT experiences interruptions in communication at the perimeter, and as the WT travels throughout the system, it experiences changes in reception quality, such as fading. Other known receiver execution means use a single receiver chain, where they interrupt communication with the connected base station transmitter, and to search for and evaluate potential alternative carriers. To switch from the carrier that is temporarily in use. This approach is undesirable. The reason is that the WT interrupts the normal communication session during the search interval, consumes time to retune the filter, eg RF filter, to adjust for each search frequency and waits for the detected carrier. Therefore, it consumes time to receive and evaluate any received signal, eg, pilot signal, and then retune to the original carrier setting.

From the point of view of the above discussion, it is clear that there is a need for improved methods and equipment for efficient wireless terminal receiver design and operation. It would be advantageous if such devices and methods could estimate the quality of two alternative channels that use different carrier frequency bands at the same time without interrupting an ongoing communication session. Similarly, it allows continuous tracking of carriers of choice, wireless terminal selection of carrier frequency / cell / sector base station connection points, allowing switching before interruption of communication, switching in the conventional way. It would be advantageous if such a method were provided to allow it to happen and to be able to switch depending on other things, such as system load conditions.

The present invention relates to determining carrier availability, selecting a carrier and / or relating, eg, from one network connection point associated with one carrier, eg, relating to another carrier. Directed to methods and devices for deciding when to initiate a handoff to another connection point. Each carrier corresponds to a particular carrier frequency and corresponds to a base station network connection point that can be used by a wireless terminal to connect to a communication network over a wireless communication link. The connection point can be, for example, a base station, a sector of a base station, or, for example, a communication module within a base station sector in cases where multiple carriers are used within a sector, the communication module being used by a network connection point. Used to generate and / or process signals corresponding to a particular carrier frequency.

The methods and devices of the present invention can be used in wireless communication systems that use multiple carriers in a system, such as a spread spectrum OFDM system and / or a CDMA system, where, for example, the entire availability. Bandwidth is divided into different frequency bands, each band having an associated carrier frequency. Different cells in the system can use different carrier frequencies; different sectors of the same cell can use different carrier frequencies. In some embodiments, the same sector in a cell can use different carrier frequencies, eg, at different power levels, for additional diversity and additional base station connection options, eg, downlink traffic channel signaling. Provides an alternative connection point for.

The present invention allows the receiver of a wireless terminal to stay in its currently operating carrier frequency band and still receive information from adjacent sectors and / or cell base station transmitters. To. The transmitter can be used to identify carriers used by neighboring sectors or cells, and used to determine when a switch to another carrier should be made. It is possible to be done.

In systems using the present invention, base station transmitters in different sectors and / or cells periodically transmit high power signals, sometimes referred to as beacon signals, into the frequency bands used in neighboring sectors or cells. To do. A beacon signal is a signal that contains one or more narrow signal components (in terms of frequency), such as a signal tone, which is relatively high compared to other signals such as user data signals. It is transmitted by power. In certain embodiments, the beacon signal comprises one or more signal components, each of which corresponds to a different tone. The beacon signal component in certain embodiments is 10 times, 20 times, 30 times or more of the signal energy per tone of the average signal tone used to transmit user data and / or non-beacon control signals. It includes signal energy per tone that is a multiple of the above.

Multiple beacons, eg, multiple high power tones, can be transmitted simultaneously, but in many embodiments, at most one beacon signal will have one of the given transmit time periods, eg, It is transmitted by the transmitter in the symbol transmission period. The one beacon signal can include one high power signal tone or, in certain embodiments, multiple high power tones.

Each beacon signal component is transmitted, for example, at a predetermined frequency, thereby allowing the beacon signal component to be used in transmitting information such as cell information, sector information and / or carrier information. .. In certain embodiments, the beacon signal corresponds to one tone. Beacon signal components are fixed in terms of frequency or can be transmitted at different frequencies and at different times according to a predetermined pattern, such as a particular hopping sequence corresponding to a cell or sector. Is.

According to the present invention, a wireless terminal, eg, a mobile node, uses a beacon signal component transmitted by a point of connection of a different network within, eg, a monitored frequency band, used by that mobile node. To detect. The relatively high power levels of the beacon signal components allow them to be easily detected using an energy detection method that does not require symbol timing synchronization with the transmitting base station. The frequency of the detected beacon signal component, which in the case of a single tone beacon signal is the frequency of the beacon signal itself, is then, for example, the frequency at which the energy of the detected beacon signal component is concentrated at that frequency. Is determined by the wireless terminal. Beacon component frequency determination may occur, and often occurs frequently, before the wireless terminal determines the carrier frequency or symbol timing associated with the cell or sector transmitting the beacon signal. The frequency of the received beacon signal component, and in various embodiments, is to determine the sector or cell from which the detected beacon signal component is transmitted and / or the carrier associated with the sector or cell transmitting. It can be used to determine the frequency. The mobile should be used by storing information about the signal strength of the received beacon component, eg, power, and by comparing the strength of the beacon signal component corresponding to the point of connection of another network. The carrier frequency can be selected and / or when the handoff should be performed can be determined. The carrier frequency at which the handoff is about to take place can be determined from the frequency of the received beacon signal component that triggered the handoff operation (sometimes considered in combination with other information). In many cases, the carrier frequencies of neighboring sectors or cells indicate the carrier frequencies used by different sectors and / or cells to transmit the beacon signal.

Information obtained from beacon signal components transmitted by neighboring sectors or cells within the frequency band of adjacent sectors or cells indicates when the boundary region is approached, when the wireless terminal should perform a handoff, and the handoff. Allows wireless terminals in adjacent sectors or cells to identify later which new carrier frequency should be used. This can be achieved without the wireless terminal switching its receiver to another frequency band when attempting to identify carriers in neighboring sectors and / or cells.

In one particular embodiment of the embodiment, multiple frequency bands are used in the communication system, where each frequency band uses a different carrier frequency. A wireless terminal, eg, a mobile node, listens to one frequency band at a time, eg, the frequency band corresponding to a carrier. The carrier uses the carrier to receive and / or transmit voice data, text data, video data or other application data. In the embodiment of this particular embodiment, when the wireless terminal receives a signal, it performs a time domain to frequency domain conversion operation, for example, by performing a Fourier transform operation on the received signal, such as FFT or DFT. .. The resulting time-to-frequency conversion operation produces multiple signal components, such as signal tones, that correspond to different frequencies in the monitored signal band. Energy detection is performed on different signal components to generate energy estimates for each signal component, eg, energy estimates in each or more different signal tones present in the received signal. Based on the signal component energy, a decision is made as to whether the signal component corresponds to the received beacon signal. This beacon determination step can be performed by comparing the signal component energies to the threshold energy level, which indicates the presence of the beacon signal when exceeded. When the signal component corresponding to the beacon signal is detected, the frequency of the signal component and therefore the frequency of the detected beacon signal is the cell information corresponding to the base station transmitter that subsequently transmitted the detected beacon signal, Used to determine sector information and / or carrier information. In various embodiments, the detected energies of the beacon signal components corresponding to the beacons received from different transmitters are compared. Carrier selection and handoff decisions are based on the results of comparisons of beacon signal strength, eg energy. From the connection point corresponding to the first received beacon signal and another

The embodiments of the above embodiment are intended to be exemplary. A plurality of execution means utilizing the present invention performs all or many of the steps described above. However, it should be noted that another means of execution still realizes the benefits from the present invention, while using only some of the steps described above in combination.

Many additional features, advantages and embodiments of the present invention are described in the detailed description below.

<figref num="1">FIG. 1 is a diagram of a specific example wireless communication system implemented in accordance with the present invention and supporting multiple carriers using the methods of the present invention.</figref><figref num="2">FIG. 2 is a diagram of a specific example base station implemented in accordance with the present invention and using the methods of the present invention.</figref><figref num="3">FIG. 3 is a diagram of a specific example of a wireless terminal that is implemented in accordance with the present invention and uses the methods of the present invention.</figref><figref num="4">FIG. 4 is a diagram of a specific embodiment of a receiver capable of processing two components of a signal simultaneously received from the same selected carrier band, where each component has different information, eg, two. Communicating information corresponding to one of the different carrier bands, the receiver is given according to the present invention and using the methods of the present invention.</figref><figref num="5">FIG. 5 is a diagram illustrating base station signaling of a specific example related to a wireless terminal embodiment of a specific example utilizing the embodiment of the specific example of the single receiver chain receiver of FIG. 4 according to the present invention.</figref><figref num="6A">FIG. 6A is a flowchart illustrating a communication method of a specific example of operating a communication system including a wireless terminal of the specific example using the single receiver chain receiver of the specific example of FIG. 4 according to the present invention.</figref><figref num="6B">FIG. 6B is a flowchart illustrating a communication method of a specific example of operating a communication system including a wireless terminal of the specific example using the single receiver chain receiver of the specific example of FIG. 4 according to the present invention.</figref><figref num="7">FIG. 7 is a partial diagram of a wireless communication system of a specific example performed in accordance with the present invention, the system includes a wireless terminal of the specific example on the move, and is used for the purpose of further explaining the present invention. ..</figref><figref num="8">FIG. 8 is a diagram of an embodiment of another embodiment of a receiver performed in accordance with the present invention, the receiver can be used in the wireless terminal shown in FIG.</figref><figref num="9">FIG. 9 is a diagram illustrating a specific example base station sector transmitter signaling including a beacon corresponding to the sector transmitter, the beacon being transmitted to a plurality of bands according to the present invention, and the signaling is shown in FIG. It can be transmitted from the base station of the specific example shown.</figref><figref num="10">FIG. 10 is a diagram illustrating a received signal of the specific example in the receiver of the wireless terminal of the specific example shown in FIG. 7.</figref><figref num="11">FIG. 11 is a diagram illustrating wireless terminal receiver processing of a specific example of the received signal of the specific example of FIG. 10 and band selection of the specific example according to the present invention.</figref><figref num="12">FIG. 12 is a diagram illustrating base station sector transmitter signaling of a specific example including a beacon corresponding to a sector transmitter, the beacon being transmitted to a plurality of bands according to the present invention, and a wireless terminal providing a new band. After selecting and changing the connection point, signaling can be transmitted from the example base station shown in FIG.</figref><figref num="13">FIG. 13 is an explanatory diagram of a beacon signal of a specific example having a timing offset with respect to adjacent sectors, and is used for the purpose of further explaining the features of the present invention.</figref><figref num="14">Figure 14 relates to determining the availability of carriers that can be used, and is a wireless terminal to determine when to initiate a handoff from one carrier frequency to another. It is explanatory drawing of and various elements included in the wireless terminal.</figref><figref num="15">FIG. 15 is an explanatory diagram of a wireless terminal reception signal processing module of a specific example given according to the present invention, which can be used in the wireless terminal of FIG.</figref><figref num="16A">FIG. 16A is a flowchart of a specific example method of operating the WT in an OFDM communication system according to the present invention.</figref><figref num="16B">FIG. 16B is a flowchart of a specific example method of operating the WT in an OFDM communication system according to the present invention.</figref>

FIG. 1 shows an exemplary wireless communication system 100 implemented in accordance with the present invention and supporting multiple carrier and spectral spread signaling. System 100 uses the devices and methods of the present invention. FIG. 1 includes a plurality of specific examples of multi-sector cells, cell 1 102, cell 2 104, and cell 3 106. Each cell (102,104,106) represents a radio communicable area for a base station (BS: base station) and (BS1 108, BS2 110, BS3 112), respectively. In the embodiment of the specific example, each cell 102, 104, 106 includes three sectors (A, B, C). Cell 1 102 includes sector A114, sector B116, and sector C118. Cell 2 104 includes sector A120, sector B122, and sector C124. Cell 3 106 includes sector A126, sector B128, and sector C130. In other embodiments, different numbers of sectors are possible, eg, 1 sector per cell, 2 sectors per cell, or more than 3 sectors per cell. Moreover, different cells can contain different numbers of sectors.

A wireless terminal (WT), eg, a mobile node (MN), can move the entire system and communicate with a peer node, eg, another MN, via a wireless link to BS. it can. In sector A114 of cell 1102, WTs (132,134) are connected to BS1 108 via wireless links (133,135), respectively. In sector B116 of cell 1102, WTs (136,138) are connected to BS1 108 via wireless links (137,139), respectively. In sector C118 of cell 1102, WTs (140,142) are connected to BS1 108 via wireless links (141,143), respectively. In sector A120 of cell 2 104, WT (144,146) are connected to BS2 110 via wireless links (145,147), respectively. In sector B122 of cell 2 104, WT (148,150) are connected to BS2 110 via wireless links (149,151), respectively. Cell 2 In sector C124 of 104, WTs (152,154) are connected to BS2 110 via wireless links (153,155), respectively.

Multiple BSs can be connected together over a network, thus providing connectivity to multiple WTs inside a given cell to multiple peers located outside the given cell. To do. In system 100, BSs (108,110,112) are connected to network node 168 via network links (170,172,174), respectively. A network node 168, eg, a router, connects to the Internet to other network nodes, eg, another base station, router, home agent node, AAA server node, etc., and over network link 176. Will be done. Network links 170,172,174,176 can be, for example, fiber optic links.

BS108,110,112 includes sector-divided transmitters, each sector transmitter being used for conventional signaling, eg, a downlink traffic signal destined for a particular WT, in accordance with the present invention. In contrast, it uses a unique assigned carrier frequency. The assigned carrier frequency of the sector transmitter used for normal signaling is also broadcast from BS to multiple WTs, such as assigned signals, pilot signals, and / or beacon signals. Transport the signal. Moreover, according to the present invention, each base station sector transmitter may, for example, be a pilot signal and / or a beacon signal within a range of carrier frequency bands assigned to the normal signaling of adjacent cell / sector transmitters. Send additional downlink signals such as. Such a downlink signal provides information to a WT, eg, WT132, which evaluates which carrier frequency to select and which corresponding base station sector / cell to use as a junction. It can be used for and to determine. The WT, eg, WT132, includes a receiver capable of processing information from BS108,110,112 sector transmitters and provides information over multiple carrier frequency bands of choice. The carrier frequency band can be used for normal communication, eg, downlink traffic channel signaling to the WT, and can be selected by the WT.

FIG. 2 illustrates a specific example of a base station 200, or an access node, given in accordance with the present invention. The BS is called an access node because it acts as a point of WT network connectivity and provides WT access to the network. The base station 200 of FIG. 2 may be a more detailed representation of any of the base stations 108,110,112 of the system 100 of FIG. Base station 200 includes a processor 202 connected together via bus 214, such as a CPU, a receiver 204 including a decoder 206, a sectorized transmitter 208, a memory 210, and an I / O interface 212. Various elements can exchange data and information via the bus. The receiver 204 is connected to the sector-divided antenna 216 and can receive signals from the wireless terminal 300 (see FIG. 3) in each of the sectors covered by the base station 200. The receiver decoder 206 decodes the received uplink signal and extracts the information encoded by the WT300 prior to transmission. The sectorized transmitter 208 includes a plurality of transmitters, a sector 1 transmitter 218, and a sector N transmitter 220. Each sector transmitter (218,220) includes an encoder (222,224) for encoding downlink data / information and is connected to an antenna (226,228), respectively. Each antenna 226,228 corresponds to a different sector and is usually oriented to transmit to a sector in which the antenna can correspond and be located. Antennas 226,228 may correspond to different elements of one multi-sector antenna, which may be separate or have different elements for different sectors. Each sector transmitter (218,220) has an assigned carrier frequency that should be used for normal signaling, eg downlink traffic signaling.Has a band. Each sector transmitter (218,220) is capable of transmitting downlink signals, such as assigned signals, data and control signals, pilot signals, and / or beacon signals, within its own assigned carrier frequency band. is there. Each sector transmitter (218,220) also has an additional downlink signal within another carrier frequency band, eg, a carrier frequency band allocated for normal signaling in adjacent cells / sectors, according to the present invention. , For example, transmit a pilot signal and / or a beacon signal. Base station I / O interface 212 connects base station 200 to another network node, such as another access node, router, AAA server, home agent node, and the Internet. Memory 210 includes routine 230 and data / information 232. Processor 202 executes routine 230 and uses the data / information 232 in memory 210 to control the operation of base station 200. The operation of base station 200 includes scheduling users on different carrier frequencies using different power levels, power controls, timing controls, communications, signaling, and beacon signaling according to the present invention. Scheduling of a particular user, eg, a particular WT300, on a particular carrier frequency can be a response to the choices made by the WT300 in accordance with the present invention.

The data / information 232 in the memory 210 is data 234, such as user data being transmitted to the wireless terminal 300 and user data being received from the wireless terminal 300, carrier frequencies and sectors associated with each sector. Includes sector information 236, including data transmission power levels associated with each carrier frequency within, carrier frequency information (carrier 1 information 238, carrier N information 240), beacon information 242, and system loading information 243. Carrier frequency information (238,240) includes information that defines carrier frequencies and associated bandwidths. Beacon information 242 includes tone information, such as information related to the beacon signal in each sector having a unique frequency and carrier, and sequence timing related to transmitting the beacon signal. System loading information 243 includes synthetic loading information for each of the various carrier bands supported by base station 200. System loading information 243 can be transmitted from base station 200 to WT300. In certain embodiments, the WT300 can use the information in the process of determining the selection of bandwidth to be set inside the WT receiver.

The data / information 232 in the memory 210 also includes a set of multiple WT data / information 244s: WT1 data / information 246, WTN data / information 248, one set for each WT. The WT1 data / information 246 includes user data being transferred from WT1 to /, a terminal ID that associates the WT with the base station 200, a sector ID that identifies the sector in which WT1 is currently located, and a down. Contains carrier frequency information that associates WT1 with a particular carrier frequency used for link signaling.

Base station routine 230 includes communication routine 250 and base station control routine 252. The communication routine 250 can provide the various communication protocols used by the base station 200. Base station control routine 252 includes scheduler module 254 and signaling routine 256. Base station control routine 252 controls base station operation, scheduling, signaling, and beacon signaling, including receiver 204, transmitter (218,220), according to the present invention. The scheduler module 254, eg, the scheduler, is used to schedule wireless link resources to the wireless terminal 300 for uplink and downlink communications, eg, bandwidth over time. Base station control routine 252 also includes signaling routine 256. It controls receiver 204, decoder 206, transmitter 218,220, encoder 222,224, normal signal generation, data and control tone hopping, and signal repetition. Beacon routine 258, also included in signaling routine 256, uses beacon information 242 to control the generation and transmission of beacon signals in accordance with the present invention. According to the present invention, in certain embodiments, a beacon signal, eg, a high power signal that is relatively narrow in frequency, is each in each of the carrier frequency bands used by that sector / cell or by adjacent sectors / cells. Can be transmitted within a sector. These beacon signals are used by the WT300 in certain embodiments to compare the available carriers of the alternatives and to compare the downlink channels of the alternatives using the carriers of the alternatives.

FIG. 3 illustrates a specific example of a wireless terminal 300, eg, a mobile node, which is implemented in accordance with the present invention and uses the methods of the present invention. The wireless terminal 300 of FIG. 3 may be a more detailed description of any of WT132,134,136,138,140,142,144,146,148,150,152,154,156,158,160,162,164,166 of the system of FIG. The wireless terminal 300 includes a receiver 302, a transmitter 304, a processor 306, for example, a CPU and a memory 308 connected together via the bus 310, and various elements can exchange data and information via the bus. ..

The receiver 302 is connected to the antenna 312 and the downlink signal is received from the plurality of base station sector transmitters and the corresponding sector antennas 226,228 through the antenna 312. The receiver 302 includes a single spectrum spread receiver chain 314 and a band selection controller 316. Spectral diffusion receiver chain 314 includes an RF module (frequency synchronization circuit) 320 for performing filtering and other operations. The RF module 320 includes a passband filter 321 that can be controlled to remove frequencies outside the selected band and, on the other hand, to pass frequencies that fall within the selected band, eg, carrier signals. The extension module 322 is included in the receiver chain 314 along with the digital signal processing module 324 and the energy detection / SNR detection module 334. The digital signal processing module 324 includes a decoder 326 and a signal quality detector module 328.

The RF module 320, receiver chain extension module 322, digital signal processing module 324, and energy detection / SNR detection module 334 are used to receive, decode, measure, and evaluate various signals. , Various signals are transmitted by multiple cell / sector base station transmitters using the currently selected first band associated with a particular first carrier frequency, eg, assigned signals, Includes downlink traffic channel data and information signals, pilot signals, and / or beacon signals. The band selection controller 316 outputs a signal to the RF module 320 and the adjustable filter 321 contained therein to select a specific carrier frequency; the RF module 320 is within the selected carrier frequency band. Pass the received signal components of and remove at least multiple signals outside the selected carrier frequency band. The RF module 320 also performs additional processing, eg, multiple signals are hybridized in baseband. The output signal passed by the RF module 320 is processed, eg, filtered by the baseband, converted from an analog signal to a digital signal, and further filtered by the receiver chain extension module 322 by the digital filter. The signal is then output from the extension module 322 and transferred to the digital signal processing module 324 and the energy detection / SNR detection module 334. A plurality of signal components corresponding to the currently selected band, for example, from the first base station cell / sector transmitter, are processed by the digital signal processing module 324; On the other hand, another signal component corresponding to another carrier band, eg, from a second cell / sector transmitter, is processed by the energy detection / SNR detection module 334. The digital signal processing module includes a decoder 326, which can decode the downlink traffic signal directed to a particular WT300; on the other hand, the energy detection / SNR detection module 334 does not include such decoding capability.

The output from the signal quality detector module 328 of the digital signal processing module 324 and from the energy detection / SNR detection module 334, for example, the quality index value is input to the band selection module 316, the band selection module 316 is the present invention. Therefore, the selection of the frequency band setting in the RF module (frequency synchronization circuit) 320 is controlled.

Transmitter 304 includes encoder 336 and is connected to transmitter antenna 338. A block of data / information, eg, uplink data / information, can be encoded by encoder 336 and then transmitted to base station 200 via antenna 338.

Memory 308 contains routine 340 and data / information 342. The processor 306, for example the CPU, executes routine 340 and uses the data / information 342 in memory 308 to operate the WT300 and performs the methods of the invention.

Wireless terminal data / information 342 includes user data 344, user device / session resource information 346, currently selected carrier information 348, alternative carrier information 350, cell / sector information 352, carrier frequency information 354, detection. The signal information 356 and the carrier selection information 358 are included.

User data 344 includes data, information and files that are intended to be transmitted to / or received from the peer node in a communication session using the wireless terminal 300. User / device / session resource information 346 includes, for example, terminal ID information, base station ID information, sector ID information, selected carrier frequency information, mode information, and identified beacon information. The terminal ID information can be an identifier assigned to the WT300 by the base station 200 to which the WT300 is connected to the base station, which identifies the wireless terminal 300 to the base station 200. The base station ID information can be, for example, the value of the slope associated with the base station 200 and used in the hopping sequence. The sector ID information includes information that identifies the sector ID of the transmitter / receiver of the base station divided into sectors, normal signaling is communicated via the transmitter / receiver, and the wireless terminal 300 It can correspond to the sector of the cell located in that sector. The selected carrier frequency information is information that identifies the carrier, eg, the carrier on which the RF module is tuned to that carrier, downlink data signaling, eg, information used by the BS for traffic channel signals. including. The mode information identifies whether the wireless terminal 300 is in the on / hold / sleep state.

The current selected carrier information 348 contains information that identifies the selected carrier in which the RF module 320 is tuned to that carrier by the band selection controller 316. The alternative carrier information 350 includes information for which the information evaluated by the energy detection / SNR detection module 334 identifies the alternative carrier corresponding to that carrier. The cell / sector ID information 352 can include information used in processing data, information, control signals, and beacon signals to construct hopping sequences used in transmission and reception. Carrier frequency information 354 can include information relating to each sector / cell of a base station in a communication system having a particular carrier frequency or multiple carrier frequencies, frequency bands, beacon signals, and multiple tones sets. .. Carrier frequency information 354 also includes quality indicator related information 355, which associates a particular carrier frequency with each quality indicator value, and this particular carrier frequency may be selected by the band selection controller 316. it can.

The detected signal information 356 includes signal energy information 360, SNR information 362, estimated error information 364, a first quality index value 366, and a second quality index value 368. The detected signal information 356 also includes synchronization information 370 and broadcast communication signal information 372.

The detected signal information 356 includes information output from the signal quality detector 328 of the digital signal processing module 324 and information output from the energy detection / SNR detection module 334 in the receiver 302. The signal quality detector module 328 can measure and record the signal energy 360, SNR362, and / or estimated error rate 364 of the signal component from the first transmitter, and the receiver 302 is currently in that band. Determines the first quality indicator value 366, which is an indicator of the quality of the channel between the first transmitter and the WT300, eg, the downlink traffic channel, when using the configured carrier bandwidth. .. The energy detection / SNR detection module 334 can measure and record the signal energy 360 and / or SNR362 of the signal component from the second transmitter, a second on a possible channel, eg, the carrier band of choice. Determine a second quality indicator value of 368, which is an indicator of the downlink traffic channel between the transmitter and the WT300.

The synchronization information 370, in some CDMA embodiments, provides timing synchronization information based on, for example, the pilot signal that is used and / or acquired by the receiver while processing, for example, the CDMA pilot signal. Can include. In some OFDM embodiments, the synchronization information can include symbol timing recovery information. The broadcast information 372 may include information related to, for example, broadcast communication that is used and / or acquired by the receiver while processing the signal, eg, a pilot signal or beacon signal. it can.

The carrier selection information 358 includes predetermined threshold value information 374, preset interval information 376, rate change information 378, and quality of service (QoS). Service) Includes information 380 and system loading information 382. The carrier selection information 358 is used in WT300 when making a band selection determination when evaluating the detected signal information, for example, when comparing the first quality index value 366 with the second quality index value 368. Information used by, for example, criteria, limits, etc. The predetermined threshold information 374 includes the level used for comparison with the quality index values 366,368 to make a bandwidth selection decision. The preselected interval information 376 includes a time interval of a fixed period and a fixed number of signal measurement intervals. Each of them should have a consistent state in which, for example, the second quality indicator exceeds the first quality indicator at that interval before the bandwidth selection controller 316 changes the selection for the receiver RF module 320. , Can be used to specify a predetermined interval. The rate change information 378 shows that the first signal quality indicator value 366 decreases over time, while the second signal quality indicator value 368 increases over time, and the first quality indicator value and the first. Includes criteria used to identify when the difference between the two quality indicators changes the sign. Quality of service (QoS) information 380 includes QoS provided to individual users, bandwidth selection as a function of the level of QoS being provided to one user, and the level of QoS being provided to that user. Contains information related to changes in selection as a result of changes in. System loading information 382 includes received information related to system loading communicated by base station 200 that can be used to make functional control decisions regarding bandwidth selection.

The WT routine 340 includes a communication routine 384 and a wireless terminal control routine 386. The wireless terminal communication routine 384 provides various communication protocols used by the wireless terminal 300. The wireless terminal control routine 386 performs the functional control operations of the wireless terminal 300, which provides power control, timing control, signaling control, data processing, I / O, receiver control and carrier bandwidth selection functions according to the present invention. Including. The WT control routine 386 includes a signaling routine 388, a receiver control module 390 and a carrier bandwidth selection module 392. The signaling routine 388, which uses the data / information 342 in the memory 308, controls the signaling of the WT300, for example, uplink-communicated signals and downlink-communicated signals. In cooperation with modules 324,334, the receiver controller module 390 is decoded according to the present invention, energy detection and / or SNR detection performed on the received signal, and a first quality indicator value and a second. Controls the operation of receiver 302, including the occurrence of quality index values 366,368. In cooperation with the band selection controller 316, the carrier band selection module 392 was derived from a received signal containing the first quality index value and the second quality index value 366,368, as well as the carrier selection information 358, according to the present invention. The data / information is used to make decisions about the carrier selected to tune the RF module 320 of receiver 302.

FIG. 4 is an example of a specific example of a wireless terminal receiver 501 / antenna 502 combination 500 given according to the present invention. The receiver / antenna combination 500 of FIG. 4 can be used as the receiver 302 / antenna 312 combination in the WT300 of FIG. Receiver 501 illustrates embodiments of a specific example of a receiver according to the present invention, which can simultaneously process two components of a received signal contained in the same selected carrier band, each component being different. It carries information, eg, information corresponding to one of two different carrier bands transmitted by different transmitters and / or transmitted by different transmitting antennas. The two signal components can correspond to different sectors and / or different cells in one cell.

Receiver 501 in FIG. 4 uses a single RF processing chain that includes a single RF processing module (frequency synchronization module) 502. The receiver 501 is connected to an antenna 504 that receives downlink signals from a plurality of sector / cell base station transmitters. The antenna 504 is connected to the RF processing module 502. The RF processing module 502 includes a selectable RF filter 506 and a mixer circuit 508. The RF filter 506 can be given as a passband filter and acts as a frequency synchronization circuit. The RF processing module 502 is tuned to the carrier frequency selected by the band selection controller 510. The RF filter passes the received signal components within the selected carrier band and removes at least multiple signal components outside the selected carrier band.

The passband signal received from the antenna 504 is input to the RF filter 506 and processed by the mixer circuit 508, resulting in a baseband signal. The resulting baseband signal is output from the RF processing module 502 and input to the baseband filter 512. The filtered output from the baseband filter 512 is input to the A / D converter module 514, where analog-to-digital conversion is performed. The resulting output digital signal is input to the digital filter 516 for additional filtering. The output of the digital filter 516, eg, the first signal component 517 originally supplied from the first base station cell / sector transmitter, is then input to the digital signal processing module 518, while another one. The output of the digital filter 516, for example, the second signal component 519 originally supplied from the second base station cell / sector transmitter, is output to the energy detection / SNR detection module 536. The digital signal processing module 518 includes a timing synchronization module 522, a decoder 523, and a signal quality detector 526. Therefore, the digital signal processing module 518 can fully decode broadcast information, as well as WT-specific information, such as information directed for one WT and not for another WT. Is.

The timing synchronization module 522 is used for timing synchronization of received data to be processed, for example, a received downlink signal. CDMA embodiments, as well as OFDM embodiments, are expected. The timing synchronization module 522 in the CDMA embodiment can be provided using known despreading techniques. The timing synchronization module 522 in the OFDM embodiment can be provided as a symbol timing reproduction circuit using a known technique. The decoder 523 is directed at a broadcast communication module 524 for decoding received broadcast signals, such as beacon signals, pilot signals, etc., and a specific WT 300 to which the receiver 501 belongs to that WT. Includes a mobile-specific module 525 for decoding received downlink data / information, such as a downlink traffic signal.

The signal quality detector 526 includes a signal energy measuring circuit 528, an SNR circuit 530 and / or an error estimator 532. The signal quality detector 526 obtains quality estimates for the channel from the first base station cell / sector transmitter to the WT300 used for downlink traffic channel signaling. The quality estimate is the output of the signal energy measurement circuit 528 (eg, the quality estimate can be the energy measured in a signal component such as a beacon tone, or is based on the energy of the signal or signal component). Based on the measured error rate or estimated error rate of the output of the SNR circuit 530, which is a function of the measured signal energy, and / or the received data / information determined by the error estimator 532. The quality estimation information 533, for example, the quality index value corresponding to the currently selected carrier band, is transferred to the area selection controller 512 for use in making the band selection band determination.

In the execution means of FIG. 4, the second signal component processing is performed by another set of receiver components, such as an optional timing synchronization module, an optional broadcast detector 534, and an energy detection / SNR detection module 536. Shown to be executed. However, it is highly appreciated that the elements of the digital signal processing module 518 can be used on a time-divided basis, where the first signal component and the second signal component and second to generate quality index values. The signal components of are of the same type, eg, OFDM signals. If the second signal component is a beacon signal or another signal that does not require timing synchronization and / or decoding to generate a quality indicator value, the timing synchronization module 520 and broadcast decoder 534 are omitted. May be done. However, if the first signal component corresponds to a first type of signal, eg, an OFDM signal, and the second signal component corresponds to a second type of signal, eg, a CDMA signal, then the first Separate signals and / or modules for generating signal quality values for the signal component of and the second signal component can be configured to handle different types of signals, eg, reconfigurable. It can be even more cost effective than using a simple circuit system.

In some embodiments, for example, in the CDMA embodiment, the second signal component 519 is processed via the timing synchronization module 520. The timing synchronization module 520 in the CDMA embodiment can be provided using known despreading techniques. In some embodiments, for example, in various CDMA embodiments, the second signal component 519 is similarly processed via the broadcast decoder 534.

A second signal component, which may be subjected to the optional processing described above, is input to the energy detection and / or SNR detection module 536. The processed received signal component that is going to be evaluated by the energy detection and / or SNR detection module 536 may transmit, for example, a second transmitter, eg, a first signal component, in some OFDM embodiments. It can be a detected beacon signal transmitted from an adjacent cell / sector base station transmitter, with respect to one cell / sector base station transmitter. Therefore, in certain embodiments, the quality estimation information 537 is a value indicating the energy detected in the beacon signal, for example, the beacon tone, or a value based on the energy of the beacon signal. The processed received signal component evaluated by the energy detection and / or SNR detection module 536 is, for example, in some CDMA embodiments, a first transmitter transmitting a second transmitter, eg, a first signal component. It can be a detected pilot signal transmitted from an adjacent cell / sector base station transmitter associated with the cell / sector base station transmitter. The energy detection and / or SNR detection module 536 provides quality estimates for possible downlink channels between the second cell / sector base station transmitter and the WT300 corresponding to the second signal component evaluated. Generates information that can be used as signal quality estimation information 537. The quality estimates generated are based on signal energy measurements or SNR measurements that are a function of the detected signal energy. The signal quality estimation information 537 has, for example, a first frequency band and a second frequency band corresponding to the first signal component and the second signal component, respectively, for use in making a band selection determination. Transferred to the band selection controller 510 for selection between.

In some embodiments, the energy detection and / or SNR detection module 536 is less computationally complex than the digital signal processing module 518 in either the number of gates or the number of executable instructions. This is possible, and decoding is often used, because in many cases it is not necessary to decode the received signal component in order to generate quality estimation information corresponding to the second signal component. In this case, it is possible to be limited to decoding the broadcast communication data, and the broadcast communication data is easier to decode than the mobile-specific data, because it is mobile-specific. Because of the type of coding used compared to the case of data and / or because the broadcast signal is intended to reach multiple mobile devices, rather than the power transmission level of the mobile-specific data. This is because the power transmission level of broadcast communication data is often high.

The signal component quality information (533,537) transferred from the digital signal processing module 518 and the energy detection and / or SNR detection module 536 respectively is used to make a decision regarding the setting of the carrier frequency band to be used by the RF processing module 502. Used by the band selection controller 510. For example, which band, and therefore which base station sector transmitter, should be selected to receive the downlink communication.

In certain embodiments, receiver 501 in FIG. 4 is a spread spectrum receiver that processes spectral spread signals such as CDMA and / or OFDM. In some OFDM embodiments, the optional timing synchronization module 520 corresponding to the second component is not used. In some OFDM embodiments, the broadcast decoder 534 may be used, while in another OFDM embodiment, the broadcast decoder 534 is not required and is omitted. In the embodiment in which the second signal component is a CDMA signal, the timing synchronization module 520 is used, but the broadcast communication decoder 534 may or may not be used.

The receiver 501 of FIG. 4 includes an I / O interface 507 connected to the digital signal processing module 518, the energy detection / SNR detection module 536 and the band selection controller 510 via the bus 509, and various elements via the bus. Can exchange data and information. In other embodiments, the bus 509 can be connected to another receiver component, such as the broadcast communication decoder 534 and / or the timing synchronization decoder 534. The receiver 501 can communicate with another element of the WT300 via the I / O interface 507 that connects the receiver 501 to bus 312. The decoded downlink traffic channel signal may be transmitted via interface 507 to one or more external devices and / or another WT component, such as a display.

FIG. 5 is an explanatory diagram 600 used to explain an embodiment of a specific example of the present invention using the single RF processing module receiver 500 of FIG. Two network connection points 101,607 are shown. Each network connection point can function as a connection point of a wireless terminal to the network via a wireless connection unit. Network connection points 601,607 can be in the same cell, in another cell, and even in the same sector of one cell, depending on the embodiment. Each of the network connection points 601, 602 uses a different frequency band to communicate user data. The network connection point module 1 601 includes a first BS transmitter 602 and a first BS sector receiver 603. The second network connection point module 607 includes a second base station sector transmitter 604 and a corresponding BS sector receiver 605.

The use of the first transmitter and the second transmitter 602,604 corresponding to another network connection point is that the first transmitter 602 corresponds to sector A of cell 102 of the embodiment, and the second transmitter 602. Will be described here using as an example a case corresponding to sector B of cell 102 of a specific example. Transmitters 602,604 transmit downlink signals, including, for example, normal traffic channel signals, such as user data, optional pilot signals, and beacon signals. Transmitters 602,604 can use different antennas pointed in the direction of another sector or cell. The signaling from each sector transmitter is used within the carrier frequency band specified to itself, such as the assigned signal, the optional pilot signal, and / or the optional beacon signal, and within one cell. Includes one or more, eg, two other, beacon signals within the carrier frequency band. The BS sector A transmitter 602 has a carrier frequency f.₀ Within the frequency band 618 having 624, for example, a downlink signal 606 including a sector A downlink traffic signal, a sector A allocation signal, an optional sector A pilot signal, and / or an optional sector A beacon signal is transmitted. Carrier frequency f₁ Send an optional sector A beacon signal 608 within frequency band 620 with 626, and carrier frequency f₂ The sector A beacon signal 610 is transmitted within the frequency band 622 having 628. BS sector B transmitter 604 has a carrier frequency f₂ Within the frequency band 622 having 628, for example, a downlink signal 612 including a sector B downlink traffic signal, a sector B allocation signal, an optional sector B pilot signal, and / or an optional sector B beacon signal is transmitted. The BS sector B transmitter 604 also has a carrier frequency f.₀ Transmission of sector B beacon signal within frequency band 618 with 624, and carrier frequency f₁ The sector B beacon signal 616 is transmitted within the frequency band 620 having 626.

A specific embodiment of the receiver 630, for example the receiver 500 of FIG. 4, is a carrier frequency f.₀ It is tuned to the frequency band 618 with 624. The receiver 630 receives two signal components 632,634. For example, the first signal component 632, including the normal signaling, allocation signal, pilot signal, and / or beacon signal from BS sector A transmitter 602, is processed by the digital signal processing module 518, while the second. The signal component 634, eg, the beacon signal from the BS sector B transmitter 604, is processed by the energy detection / SNR detection module 536. From the first component 632 and using the digital signal processing module 518, the receiver 630 has a carrier frequency f.₀ 624 and frequency band 618 are used to determine the quality estimate of the downlink traffic channel from the BS sector A transmitter to the receiver 630. From the second component 634 and using the energy detection / SNR detection module 536, the receiver 630 has a carrier frequency f.₂ 628 and frequency band 622 are used to determine quality estimates of possible alternative downlink traffic channels between BS sector B transmitter 604 and receiver 630.

In certain embodiments of the invention, the beacon signal may not be used, and another downlink signal may be received and processed for band selection determination. For example, each sector and / or cell transmitter may have a plurality of downlink signals, such as an assigned signal, sector / in the frequency band used by the transmitter for normal downlink traffic channel signaling. It transmits a cell base station identification signal and / or a pilot signal, and is also used by another, eg, an adjacent sector / cell transmitter, for normal downlink traffic signaling of another transmitter. Transmits multiple additional downlink signals within different frequency bands, such as sector / cell base station identification signals and / or pilot signals. Transmissions within another frequency band may occur at regular intervals, and there may correspond to a short period of time associated with the transmission of the signal into the corresponding sector by the transmitter. ..

A receiver, such as the single RF chain receiver 500 in FIG. 4, is tuned to one frequency band according to the present invention, but from multiple cell and / or sector transmitters transmitting within that frequency band. Receives the downlink signal component of. The receiver receives and processes a composite signal, a composite signal within a tuned frequency band, a composite signal containing a first signal component and a second signal component from two different transmitters. The information can be generated from a first signal component and a second signal component, which ensures quality indicator information for two alternative frequency bands, each frequency band corresponding to a different signal component. Can be used for, and is used.

In one particular embodiment of OFDM (Orthogonal Frequency Division Multiplexed), the beacon signal is transmitted as a narrow signal in terms of frequency, for example using one or a few tones. It is given as a relatively high power signal. When the beacon signal is transmitted in the OFDM embodiment of the embodiment, most of the transmission power is concentrated on one or a few tones that include the beacon signal. In some embodiments, the first signal component 632 comprises a beacon signal component corresponding to the first transmitter, while the second signal component is a second, eg, usually another sector and /. Alternatively, it includes a beacon signal corresponding to another transmitter corresponding to the cell. In one such embodiment, carrier selection is based on the evaluation of the beacon signal. In some embodiments, the beacon signal has a narrow frequency width relative to the band of the passband filter, eg, at most 1/20 of the frequency width of the passband filter.

According to the present invention, the first signal component and the second signal component can be transmitted simultaneously, for example, on different frequencies within the currently selected band. Alternatively, the first signal component and the second signal component can be transmitted and received in succession. 6A and 6B are flowcharts 700 illustrating a method of a specific example of operating a communication system according to the present invention. FIG. 6 comprises a combination of FIGS. 6A and 6B. The operation begins at step 702, where the communication system is initialized, eg, the base station is reinitialized, and the mobile node is powered on. The operation proceeds from step 702 to step 704.

In step 704, the first base station transmitter, which mainly transmits in the first frequency band, is operated to transmit the first signal component within the first frequency band. The operation proceeds from step 704 to step 706. In step 706, the second base station transmitter, which mainly transmits in the second frequency band, is such that the second signal component is transmitted, for example, periodically in the first frequency band. Is operated. In step 708, the first base station transmitter is operated to transmit signals in the second frequency band, which is different from the first frequency band, for example, periodically. In one embodiment, the second frequency band is completely out of range of the first frequency band, while in another embodiment, it is partially divided into a first frequency band and a second frequency band. May overlap. In certain embodiments, the first transmitter and the second transmitter are placed in different sectors of the same cell; the first signal component is the first antenna or the first of the same cell. The second signal component is transmitted using the antenna element corresponding to the sector; and the second signal component is transmitted using the second antenna or the antenna element corresponding to the second sector of the same cell. In some embodiments, the first transmitter and the second transmitter are placed in separate cells. In such an embodiment, the first signal component is transmitted using the antenna element corresponding to the first antenna or first cell, and the second signal component is the second antenna or second. It is transmitted using the antenna element corresponding to cell 2. The operation proceeds from step 708 to step 710.

In step 710, the receiver of the mobile node is operated to receive a signal that includes a first component and a second signal component. In certain embodiments, the signal is received over a period of time, and the first and second signal components are received at different points of time. In certain embodiments, the first signal component and the second signal component are received at the same time, for example, on different frequencies within the range of the first frequency band.

Then, in step 712, the passband filter in the receiver of the mobile node is operated to pass the first signal component and the second signal component, and the first signal component and the second frequency are passed. The components are within the selected frequency band. The passband filter removes signals outside the range of the first frequency band. In some embodiments, for example, in an OFDM embodiment where the first signal component and the second frequency component are beacon signals, the first signal component and the second signal component are the width of the passband filter. The frequency width is narrower than that of the above, for example, the frequency width of the pass band filter is at most 1/20. In certain embodiments, the first frequency band and the second frequency band are at least 1 MHz wide, and the passband filter has a passband narrower than 2 MHz wide.

The operation proceeds from step 712 to step 714. In step 714, the mobile node operates to perform a first signal measurement on the first signal component to generate a first signal quality index. In step 716, the mobile node operates to perform a second signal measurement on the second signal component to generate a second signal quality index. The operation proceeds from step 716 to step 718. In step 718, the mobile node operates in the first frequency band and in the second frequency band related to the second frequency component as a function of the first quality index and the second quality index. It works to choose between working and working. The operation proceeds from step 718 to step 720.

In certain embodiments, the receiving step 710, the filtering step 712, and the measuring steps 714,716 are repeated multiple times, and the selection between the first frequency band and the second frequency band of step 718 is selected. What is done is performed after the second quality index exceeds the first quality index during a predetermined interval, for example, a time interval of a predetermined period or a certain number of signal measurements. This is done to prevent switching bands in response to short periods of time or transient changes in state.

In certain embodiments, the choice is based on a predetermined threshold. For example, the selection may include: the lower of the first signal quality value and the second signal quality value if they both exceed the predetermined threshold during a predetermined interval. It is to select the frequency band corresponding to the signal quality value. Therefore, the lower quality, eg, the lower power band, can be selected if both signal components exhibit satisfactory conditions, freeing the higher power band and another one. To be used by mobiles.

Select if one of the first signal quality value and the second signal quality value is lower than the predetermined threshold value, thereby selecting a better band when signal quality is an issue. This can include selecting the frequency band corresponding to the higher signal quality value. The first signal quality value decreases over time, and the second signal quality value increases over time, and the difference between the first quality value and the second quality value changes the sign. If this indicates that the wireless terminal is heading towards the transmitter of the second signal component and away from the transmitter of the first component, then the selection is in the second frequency band. It is possible to include the selection of as well.

In certain embodiments, the step of selection is a function of a mobile node, eg, a quality of service (QoS) that is being provided to the user, and the function of selection is about to be provided to the user. It changes according to the information indicating the change in QoS. This change can be given as a change in the threshold quality used by the selection module to select the frequency band.

In certain embodiments, the step of choice is a function of communication system loading, and the method further receives information that is an indicator of communication system loading, eg, from a base station, and communication system. It comprises a moving body node that modifies the selected function in response to instructions for change in loading. For example, if the wireless terminal detects frequent use of the first frequency band, the selection can change the weights used in making the selection decision, giving it a stronger priority over the second frequency band. Create rights.

In step 720, the operation is managed based on whether the first frequency band is selected or the second frequency band is selected. If the first frequency band is selected, the operation proceeds to step 704 via the connection node A722: However, if the second frequency band is selected, the operation proceeds to step 724.

In step 724, the passband filter is controlled to pass through the second band instead of the first band. The operation proceeds from step 724 to step 728 via the connection node B726.

In step 728, a second base station transmitter, which primarily transmits within a second frequency band, is operated to transmit a third signal component within said second frequency band. In step 730, the first base station transmitter or the third base station transmitter, which mainly transmits within the first frequency band, sends the fourth signal component within the second frequency band. Behaved to send. In step 732, the second base station is operated to transmit a signal within the first frequency band. In step 734, the receiver of the mobile node is operated to receive a signal containing a third signal component and a fourth signal component. The operation proceeds from step 734 to step 736. In step 736, the passband filter in the mobile node is operated to pass a third signal component and a fourth signal component within the range of the second frequency band. In step 738, the mobile node is operated to perform a third signal measurement on the third signal component to generate a third signal quality indicator. In step 740, the mobile node is operated to perform a fourth signal measurement on the fourth signal component to generate a fourth signal quality indicator. The operation proceeds from step 740 to step 742.

In step 742, the mobile node operates in the first frequency band and in the second frequency band as a function of the third signal quality index and the fourth signal quality index. Behaved to select. The operation proceeds from step 742 to step 744.

In step 744, the operation proceeds based on whether a first frequency band or a second frequency band is selected. If the second frequency band is selected, the operation proceeds from step 744 to step 728 via the connection node C748. However, if the first frequency band is selected, the operation proceeds from step 744 to step 746, where the passband filter in the mobile node is said to replace the second frequency band. It is controlled to pass through the first frequency band. The operation proceeds from step 746 to step 704 via the connection node A722.

FIG. 7-12 is used to illustrate the signal and band selection of a specific example by a wireless terminal receiver of a specific example according to the present invention.

FIG. 7 shows a portion of a specific example wireless communication system 800 that is implemented in accordance with the present invention and supports multicarrier and spread spectrum OFDM signaling. System 800 may be an embodiment of a specific example of system 100 of FIG. FIG. 7 includes a plurality of specific examples of multi-sector cells, cell 1 802, cell 2 804, and cell 3 806. Each cell (802, 804, 806) represents a wireless communicable area for the base station (BS), (BS1 808, BS2 810, BS3 812), respectively. BS808,810,812 can be the BS200 of the embodiment of the embodiment of FIG. BS808,810,812 are connected together over a network and connected to another network node and the Internet. In the embodiment of the specific example, each cell 802,804,806 includes three sectors (A, B, C). Cell 1 802 includes sector A814, sector B816, and sector C818. Cell 2 804 includes sector A820, sector B822, and sector C824. Cell 3 806 includes sector A826, sector B828, and sector C830. FIG. 7 also includes a specific example WT801 implemented in accordance with the present invention. WT801 can be an embodiment of a specific example of WT300 in FIG. The current connection point for the WT801 in the specific example is the sector 3 818 transmitter on BS1 808. WT801 is moving towards BS2 810 as indicated by arrow 803.

FIG. 8 is an example of a specific example of a wireless terminal receiver 901 / antenna 902 combination 900 given according to the present invention. The receiver / antenna combination 900 of FIG. 8 can be used as the receiver 302 / antenna 312 combination in the WT300 of FIG. 3 or the WT801 of FIG. Receiver 901 illustrates a receiver of an embodiment according to the present invention, which is capable of processing multiple components of a received signal contained within the same selected carrier band. Each component transmits different information, eg, information corresponding to different carrier bands transmitted by different transmitters and / or different transmitting antennas. The embodiment of FIG. 8 is suitable when both signal components are communicated using the same technique, eg, the same type of modulation.

The receiver 901 in FIG. 8 uses a single RF processing chain that includes a single RF processing module (frequency synchronization module) 902. The receiver 901 is connected to the antenna 904, which receives downlink signals from a plurality of sector / cell base station transmitters. The antenna 904 is connected to the RF processing module 902. The RF processing module 902 includes a controllable RF filter 906 and a mixer circuit 908. The RF filter 906 can be given as a passband filter and acts as a frequency synchronization circuit. The RF processing module 902 is tuned to the carrier frequency selected by the band selection controller 910. The RF filter passes the received signal components within the selected carrier band and removes at least some signal components outside the selected carrier band.

The passband signal received from the antenna 904 is input to the RF filter 906 and processed by the mixer circuit 908 to result in a baseband signal. The resulting baseband signal is output from the RF processing module 902 and input to the baseband filter 912. The filtered output from the baseband filter 912 is input to the A / D converter module 914, where the analog-to-digital conversion is performed. The resulting output digital signal is input to the digital filter 916 for additional filtering. The output of the digital filter 916 is input to the digital signal processing module 918. The digital signal processing module 918 includes a timing synchronization module 922, a decoder 923, a beacon identification module 927, and a signal quality detector 926. Therefore, the digital signal processing module 918 can completely decode WT-specific information as well as broadcast communication information, for example, information directed to individual WTs rather than other WTs.

The timing synchronization module 922 is used for timing synchronization of received processed data, for example, a received downlink signal. The timing synchronization module 922 can be provided as a symbol timing reproduction circuit using known techniques. The decoder 923 refers to the broadcast communication module 924 for decoding the received broadcast communication signal, for example, the allocation signal, the pilot signal, etc., and the specific WT300 (or WT801) to which the receiver 901 belongs. Includes a mobile-specific module 925 for decoding received downlink data / information directed to, for example, a downlink traffic signal.

Beacon identification module 927 identifies received beacon signals processed using a particular base station sector transmitter associated with a particular carrier frequency used for its main downlink signaling. Each beacon signal can be, for example, a signal that occupies one OFDM symbol time in which all or nearly all sector transmitter energy is concentrated in one tone. Due to the characteristics of the OFDM beacon signal, the beacon identification module 927 can identify the beacon signal without having to process the signal through the timing synchronization module 922 or the decoder module 923.

The signal quality detector 926 includes a signal energy measurement circuit 928 and an SNR circuit 930. The signal quality detector 926 produces quality estimates for different channels from multiple base station cell / sector transmitters to the WT300 based on the measurements of the identified beacon signal received. Quality estimates are based on the signal energy measurement circuit 928 output and / or the SNR circuit 930 output, which is a function of the measured signal energy. The signal quality estimation information 933,935,937 corresponding to each received identified beacon, for example, the quality index value, is transferred to the band selection controller 910 and used when making a band selection determination.

The signal component quality information (933,935,937) transferred from the digital signal processing module 918 is used by the band selection controller 910 to make decisions about the carrier frequency band setting that is going to be used by the RF processing module 902, eg. Which band and therefore which base station sector transmitter should be selected to receive downlink communication.

The receiver 901 of FIG. 8 includes an I / O interface 907 connected to the digital signal processing module 918 and the band selection controller 910 via the bus 509, and various elements can exchange data and information via the bus. In other embodiments, the bus 509 may be connected to another receiver component, eg, a digital filter 916. The receiver 901 can communicate with another element of the WT300 via the I / O interface 907 that connects the receiver 901 to bus 312. The decoded downlink traffic channel signal can be transmitted via the I / O interface 907 to one or more external devices and / or another WT component, such as a display.

In FIG. 8, the output of the bandwidth selection controller 910 is used to control the RF processing module 902. In other embodiments, the band selection controller 910 may be connected to a digital filter 916 and / or a digital signal processing module 918, and the output of the band selection controller 910 is a digital filtering 916 and / or a digital signal. It can be used to control the processing module 918. In such cases, the RF processing module 902 receives and passes a wide portion of the received signal, eg, multiple bands, and the digital filtering 916 and / or the digital signal processing module 918 is a control signal or band selection. According to the signal received from the controller 910, select a portion of the received signal for further processing and filtering, or discard the rest of the received signal.

FIG. 9 is FIG. 1000 illustrating transmitter signaling of a specific example according to the present invention. It is assumed that there is a specific example wireless terminal in the multi-cell wireless communication system 800 with 3 sectors per cell in the specific example of FIG. 7 using the 5 MHz whole system BW1001. Wireless terminal 801, for example, a moving mobile node is currently located in system 800, resulting in multiple signals from BS cell 1 sector C transmitter 1002, from BS cell 2 sector B transmitter 1004. It is assumed that it is possible to receive a plurality of signals, a plurality of signals from the BS cell 3-sector transmitter 1006. The WT801 was previously closest to transmitter 1002, but now assumes it is closest to transmitter 1004.

BS cell 1 sector C transmitter 1002 has a carrier frequency f within the range of 1.25MHz BW band 1010.₀ Use 1008 to send the downlink signal 1020. Signal 1020 includes downlink traffic signal 1021 for WT represented by a small rectangle and beacon signal 1024 represented by a large blackened rectangle. Beacon signals are shown in larger sizes than regular signals, demonstrating that beacon signals have a much higher transmit energy concentration per tone than regular signals, detecting such signals. It's easy. The downlink traffic signal 1022 directed to the particular WT801 of interest, such as the spread spectrum OFDM signal, is blacked out. Moreover, the BS cell 1 sector C transmitter 1002 has a carrier frequency f.₁ Transmits the downlink signal 1026 within the 1.25MHz BW band 1014 with 1012. The downlink signal 1026 includes a beacon signal 1028. BS cell 1 sector C transmitter 1002 has a carrier frequency f₂ Transmits the downlink signal 1030 within the 1.25MHz BW band 1018 with 1016. The downlink signal 1030 includes a beacon signal 1032. In embodiments of this embodiment, beacon signals (1024,1028,1032) and conventional signaling (1021) are transmitted by transmitter 1002 at different times. Most of the time, transmitter 1002 transmits normal downlink signaling 1021, but sometimes, for example, periodically, transmitter 1002 has the total or nearly total sector transmission power concentrated on the beacon signal. Then, instead of normal signaling, a beacon signal (1024,1028, or 1032) is transmitted. The timing sequence can be constructed so that the transmitter 1002 circulates the beacons 1024,1028,1032 repeatedly.

The BS cell 2-sector B transmitter 1004 has a carrier frequency f within the range of 1.25 MHz BW band 1014.₁ The 1012 is used to transmit the downlink signal 1038. Signal 1038 includes a downlink traffic signal 1040 for the WT represented by a small rectangle and a beacon signal 1042 represented by a large blackened rectangle. Moreover, the BS cell 2-sector B transmitter 1004 transmits the downlink signal 1034 within the frequency band 1010. The downlink signal 1034 includes the beacon signal 1036. The BS cell 2-sector B transmitter 1004 similarly transmits the downlink signal 1044 within the frequency band 1018. The downlink signal 1044 includes a beacon signal 1046. In embodiments of this embodiment, beacon signals (1036,1042,1046) and conventional signaling (1040) are transmitted by transmitter 1004 at different times. Most of the time, transmitter 1004 transmits normal downlink signaling 1040, but sometimes, for example, periodically, transmitter 1004 has total or nearly total sector transmission power focused on the beacon signal. Then, instead of normal signaling, a beacon signal (1036, 1042, or 1046) is transmitted. The timing sequence can be constructed so that the transmitter 1004 circulates the beacons 1036,1042,1046 repeatedly.

BS cell 3-sector A transmitter 1006 has a carrier frequency f within the range of 1.25MHz BW band 1018.₂ Use 1016 to send the downlink signal 1056. Signal 1056 includes a downlink traffic signal 1058 for the WT represented by a small rectangle and a beacon signal 1060 represented by a large blackened rectangle. Moreover, the BS cell 3-sector A transmitter 1006 transmits the downlink signal 1048 within the frequency band 1010. The downlink signal 1048 includes the beacon signal 1050. The BS cell 3-sector A transmitter 1006 similarly transmits the downlink signal 1052 within the frequency band 1014. The downlink signal 1052 includes a beacon signal 1054. In embodiments of this embodiment, beacon signals (1050,1054,1060) and conventional signaling (1058) are transmitted by transmitter 1006 at different times. Most of the time, transmitter 1006 transmits normal downlink signaling 1058, but sometimes, for example, periodically, transmitter 1006 has the total or nearly total sector transmission power concentrated on the beacon signal. Then, instead of normal signaling, a beacon signal (1050,1054, or 1060) is transmitted. The timing sequence can be constructed so that the transmitter 1006 circulates the beacons 1050,1054,1060 repeatedly.

In an embodiment of this embodiment, each of the beacon signals (1024,1028,1032,1036,1042,1046,1050,1054,1060) is transmitted at the same transmit power level. In other embodiments, different transmit power levels can be used for different beacon signals and the WT knows the transmit power assigned to each beacon signal or is assigned to different beacon signals. It is provided to know the relationship between multiple transmit power levels.

FIG. 10 is FIG. 1100 for explaining the composite signal 1002 of a specific example in the receiving antenna of the WT receiver 801 and the related frequency information. Signal 1102 contains components 1104,1106,1108,1110,1112,1114, and 1116. Components 1104, 1108, 1112, and 1116 represent noise signals outside the frequency bands of interest 1010, 1014, 1018.

Signal 1106 has a carrier frequency f₀ Represents a received copy of a composite of signals 1020, 1034, and 1048 transmitted within band 1010 with 1008; signal 1106 also contains additional noise. The transmitted beacon signal 1024 and the usual signaling 1021,1022 have become intermediately weakened, for example due to channel gain, resulting in received signals (1024', 1021', 1022'). .. The transmitted beacon signal 1036 has been slightly reduced in strength, for example due to channel gain, resulting in the received beacon signal 1036'. The intensity of the beacon signal 1050 has been significantly reduced, for example due to channel gain, resulting in the received beacon signal 1050'. Similar to those described for FIG. 9, the signals 1024', 1022' and 1021', 1050'and 1036' in FIG. 10 may be received at different time moments.

Signal 1110 has a carrier frequency f₁ Represents a composite received copy of signals 1026,1038,1052 transmitted within band 1014 with 1012; signal 1110 also contains additional noise. The transmitted beacon signal 1042 and the normal signaling 1040 have been slightly reduced in strength, for example due to channel gain, resulting in the received signal (1042', 1040'). The transmitted beacon signal 1028 is, for example, intermediately reduced in strength due to channel gain, resulting in the received beacon signal 1028'. The transmitted beacon signal 1054 has been significantly reduced in strength, for example due to channel gain, resulting in the received beacon signal 1054'.

Signal 1114 has a carrier frequency f₂ Represents a composite received copy of signals 1030,1044,1056 transmitted within band 1018 with 1016; signal 1114 also contains additional noise. The transmitted beacon signal 1060 and the normal signaling 1058 have been significantly reduced in strength, for example due to channel gain, resulting in received signals (1060', 1058'). The transmitted beacon signal 1032 is, for example, intermediately reduced in strength due to channel gain, resulting in the received beacon signal 1032'. The transmitted beacon signal 1046 has been slightly reduced in intensity due to, for example, channel gain, resulting in the received beacon signal 1046'.

FIG. 11 is FIG. 1200 illustrating the processing of the specific example of the received signal 1102 of the composite of the specific example of FIG. 10 by the receiver 900 of FIG. 8 according to the present invention. The WT801 containing the receiver 900 is currently connected to BS1 sector 3 which uses the transmitter 1002 for downlink traffic signaling, and therefore the RF processing module 902 is the signal 1202 from the bandwidth controller 910. Controlled by carrier frequency f₀ Select band 1010 to use 1008. The RF processing module 902 extracts the baseband signal 1106', a filtered display of the information contained in the signal 1106, from signal 1102. Signal 1106'is the normal signaling 1021', specifically directed for WT801, and the beacon, corresponding to the signal (1021', 1022', 1024', 1036', 1050'), respectively. Includes signals 1024 ", 1036", 1050 ".

Arrows 1206 represent additional processing by receiver chain components 912,914,916, such as baseband filtering, A / D conversion, and digital filtering. The signal is then input to the digital signal processing module 918. Beacon identification module 927 identifies the beacon signal 1024 as related to cell 1 sector C transmitter 1002. Transmitter 1002 has a carrier frequency as its own allocated band for downlink traffic channel communication. f₀ Use 1008 and band 1010. Beacon identification module 927 identifies the beacon signal 1036 as related to cell 2 sector B transmitter 1004. Transmitter 1004 has a carrier frequency as its own allocated band for downlink traffic channel communication. f₁ Use 1012 and band 1014. Beacon identification module 927 identifies the beacon signal 1050 as related to cell 3 sector A transmitter 1006. Transmitter 1006 has a carrier frequency as its own band for downlink traffic channel communication. f₂ Use 1016 and band 1018.

The identified beacon information and beacon signals 1024 ", 1036", and 1050 "are transferred to the signal quality detector 926, where energy holdings and / or SNR information is acquired and the beacon signal (1024". , 1036 , 1050) corresponding quality estimation information (933,935,937) is generated. In this OFDM embodiment, beacon identification, beacon signal measurement, and signal quality indicator generation are performed without the use of a timing synchronization module or the need to decode modulated information from the beacon signal. In other embodiments, the information can be modulated onto the beacon signal, and a broadcast decode module may be used. Moreover, in other embodiments, additional information may be taken into account when generating quality estimates. For example, the error rate of information decoded from a received normal signal 1022 ", eg, a downlink traffic channel signal directed to a particular WT801, evaluates the quality of the channel corresponding to the beacon signal 1024". Sometimes considered. Moreover, the ratio between multiple beacon signals is used in determining the interference level when another detected beacon signal may correspond to the same carrier, for example from another cell. Can be done.

Quality estimation information 1 933 is based on the energy and / or signal-to-noise ratio estimates of the processed beacon signal 1024, and the carrier frequency f.₀Corresponds to the transmitter 1002 using. Quality estimation information 2 935 is based on the energy and / or signal-to-noise ratio estimates of the processed beacon signal 1036, and the carrier frequency f.₁Corresponds to the transmitter 1004 using. Quality estimation information 1 937 is based on the energy and / or signal-to-noise ratio estimates of the processed beacon signal 1050, and the carrier frequency f.₂Corresponds to the transmitter 1006 using.

The bandwidth selection controller receives the information 933,935 and 937 and determines that the quality of channel 2 is better than the quality of channel 3 and that the quality of channel 1 is better than the quality of channel 1 and that the WT801 should change the connection point. At the appropriate time, for example, to minimize service interruption, the bandwidth selection controller 910 sends signal 1202'to RF processing module 902 at frequency f.₁Change the selection to.

FIG. 12 is FIG. 1300 illustrating transmitter signaling of a specific example after the WT801 has changed its band selection and connection points. The WT801 can receive a plurality of signals from the BS cell 1 sector C transmitter 1002, the signal from the BS 2 sector B transmitter 1004, and the signal from the BS 3 sector transmitter 1006. The WT801 was previously closest to transmitter 1002, but now assumes it is closest to transmitter 1004.

The BS cell 1 sector C transmitter 1002 has a carrier frequency f within the band 1010.₀ The 1008 is used to transmit the downlink signal 1320. Signal 1320 includes downlink traffic signal 1321 for multiple WTs represented by small rectangles, and beacon signal 1024 represented by large blackened rectangles. Moreover, the BS cell 1 sector C transmitter 1002 has a carrier frequency f.₁ The downlink signal 1326 is transmitted to the frequency band 1014 having 1012. The downlink signal 1326 includes a beacon signal 1028. The BS cell 1 sector C transmitter 1002 also has a carrier frequency f.₂ The downlink signal 1330 is transmitted to the frequency band 1018 having 1018. The downlink signal 1330 includes a beacon signal 1032.

The BS cell 2-sector B transmitter 1004 has a carrier frequency f within the band 1014.₁ Use 1012 to send the downlink signal 1338. Signal 1338 is a downlink traffic signal 1340 for multiple WTs represented by a small rectangle containing a downlink traffic signal 1341 for a particular WT801 represented by a small blackened rectangle, and a large blackened rectangle. Includes the beacon signal 1042 represented by. Moreover, the BS cell 2-sector B transmitter 1004 transmits the downlink signal 1334 to the frequency band 1010. The downlink signal 1334 includes the beacon signal 1036. The BS cell 2-sector B transmitter 1004 similarly transmits the downlink signal 1334 to the frequency band 1018. The downlink signal 1334 includes the beacon signal 1046.

BS cell 3-sector A transmitter 1006 has a carrier frequency f within band 1018.₂ Use 1016 to send the downlink signal 1356. Signal 1356 includes downlink traffic signal 1358 for multiple WTs represented by small rectangles, and beacon signal 1060 represented by large blackened rectangles. Moreover, the BS cell 3-sector A transmitter 1006 transmits the downlink signal 1348 to the frequency band 1010. The downlink signal 1348 includes the beacon signal 1050. The BS cell 3-sector A transmitter 1006 similarly transmits the downlink signal 1352 to the frequency band 1014. The downlink signal 1352 includes a beacon signal 1054.

FIG. 13 is FIG. 1400 of a specific example beacon signal 1420 having a timing offset 1418 with respect to adjacent sectors, which is illustrated for the purpose of further explaining the features of the present invention. FIG. 13 includes a specific example of the WT1402 given in accordance with the present invention, eg, the WT801 of FIG. It is assumed that the example system is an OFDM spectral spread frequency hop system that uses beacon signaling according to the present invention. Timeline 1404 represents the time at WT receiver 1402, where WT1402 is currently connected to a BS1 sector C transmitter and the carrier frequency band of that transmitter is currently used for downlink traffic channel signaling. And assume that the WT1402 has synchronized OFDM symbol timing with respect to the BS1 sector C transmitter. Three consecutive OFDM symbol time intervals (1406,1408,1410) are shown for BS1 sector C transmitter communication. Similarly, three consecutive OFDM symbol time intervals (1412, 1414, 1416) are shown for BS2 sector B transmitter communication. Each OFDM symbol time interval (1406,1408,1410,1412,1414,1416) is approximately the same period; however, between the start of the BS1 sector C OFDM symbol time interval and the start of the BS2 sector B OFDM symbol time interval. Has a 10% offset 1418. This timing offset is due to differences between multiple base station timing generators, such as different exact start times, and / or differences due to different distances between the WT1402 and each base station transmitter. It can be because.

The BS cell 2-sector B OFDM beacon signal 1420 has been transmitted to the WT1402 as indicated by arrow 1422. During the time interval 1414, the BS cell 2-sector B OFDM beacon signal 1420 appears at the WT receiver 1402. However, since the WT is connected and synchronized to the BS1 sector C transmitter, the WT1402 only detects 90% of the energy of the beacon signal 1420 and loses, for example, the last 10% of the signal. However, this relatively high level of energy detection and a relatively small amount of related uncertainty are often sufficient to support the comparison of multiple beacon signals from adjacent cells and / or adjacent sectors. Is. According to the present invention, in multiple OFDM embodiments, the receiver does not need to resynchronize the receiver with respect to the timing for each beacon signal processed.

FIG. 14 is FIG. 1400'of a embodiment of the WT1400 implemented according to an embodiment of one embodiment of the present invention. FIG. 14 includes a receiver mobile 1401 and a transmitter module 1402' connected together via bus 1404'. Bus 1404'is also connected to the WT's processor, memory, and I / O devices. Through I / O devices, various elements can exchange data and information. The receiver 1401 includes an RF processing module 1410', a baseband filtering module 1412', an A / D module 1414', a wireless terminal received signal processing module 1416', and an I / O interface 1418'. RF processing module 1410'includes RF filtering module 1422', eg, a controllable passband filter. The RF processing module 1410'is connected to the receiving antenna 1406', and the receiver 1401 via the receiving antenna 1406' contains multiple BS sector connection points, such as beacon signals from different cells, different sectors. Downlink signals and / or multiple downlink signals using another conventional signaling carrier can be received. A signal received from a transmitter that uses a different carrier to transmit user data will have the same carrier band in which the RF filtering module 1422'(pass band filter) is tuned to that carrier band in accordance with the present invention. Avoids the need to adjust the RF band to receive beacons from transmitters that use a different frequency band for user data transmission. That is, as discussed above, the transmitter does not transmit the beacon signal only in the frequency band that the transmitter uses to communicate user data, but in neighboring sectors, cells, or the same sector. Sends a beacon signal to the frequency band of another carrier used. Beacon communication from a cell and / or sector where the wireless terminal does not have a communication link established using that cell and / or sector In addition to the issue, RF processing module 1410'is also capable of receiving beacon signals from the network connection point it is using as the current connection point. Control signals such as user data / information and pilot signals, timing control signals and power control signals should be transmitted in the frequency band where the RF processing module 1410'is set in that frequency band. Therefore, it can also be received from the transmitter in terms of current network connectivity.

The output signal from the RF processing module 1410'acts as an input to the baseband filter 1412', which performs analog filtering. The filtered signal is then input to the A / D converter module 1414', where the filtered analog signal is converted to a digital signal and the digital signal is input to the wireless terminal receive signal processing module 1416'. Is.

The wireless terminal receive signal processing module 1416'that has received a digital signal performs a DFT or FFT, performs an energy estimate, eg, performs beacon detection based on the energy level of the tone above the threshold, eg Performs normal signaling symbol detection, such as allocation signaling, determines the transmitter associated with each detected beacon, evaluates and determines the network connection point to use based on a comparison of beacon signal energies, and determines. It then initiates a handoff request when it determines that another network connection point should be used. The band selection signal 1420' output from the wireless terminal receive signal processing module 1416'is input to the RF filter 1422' and controls the time during which the receiver 1401 selects and switches the carrier band to be tuned to that band. ..

A handoff request to signal 1424, for example a new BS sector junction, passes through its own I / O interface 1418'through WT bus 1404' when module 1416' determines that the handoff should be performed. It is sent from the wireless terminal reception signal processing module 1416'to the transmitter module I / O interface 1426 via the wireless terminal. Transmitter module 1402'is connected to transmit antenna 1408' through which the WT can transmit uplink signals using current wireless links. The uplink signal can include a request to the current network connection point, eg, the BS sector, and initiates a handoff to a new network connection point selected based on the received beacon signal. The band selection control signal output by the wireless terminal reception signal processing module 1416'is supplied to the transmitter module 1402'. This signal can be used to switch the transmitter carrier band and the receiver carrier band to the band corresponding to the new BS sector connection point at an appropriate time. The appropriate time is, for example, just before the time corresponding to the assigned dedicated uplink segment corresponding to the new frequency band that can be used to register the new connection point.

FIG. 15 is a diagram of a wireless terminal reception signal processing module 1500 of a specific example executed according to one embodiment of the present invention. The WT received signal processing module may be an embodiment of a specific example of module 1416'in FIG. The WT received signal processing module 1500 of the specific example includes a Fourier transform, for example, a discrete Fourier transform and / or a fast Fourier transform (DFT / FFT) module 1502, an energy estimation module 1504, and a symbol detection module. Includes 1506, Threshold Energy Level Detection Module 1508, Threshold Determination Module 1510, Control Module 1512, Transmitter Information Determination Module 1514, Network Point Connection Determination Module 1516, and Handoff Controller Module 1570.

The DFT / FFT module 1502 receives the received signal 1518, for example, the signal in the first period of time, such as the OFDM symbol transmission time period, as input. The signal includes a plurality of signal tones, for example 113 tones in one embodiment. Each signal tone corresponds to a different frequency within the downlink frequency band. The DFT / FFT module 1502 performs an FFT or DFT on the received signal 1518 to generate and output multiple separate signal components (1520,1522,1524, ..., 1526) and each signal component (1520,1522,1524, ..., 1526). 1520,1522,1524, ..., 1526) correspond to different frequencies of the received signal. As such, module 1502 is used to perform a time signal to frequency signal conversion operation. The output signal components (1520,1522,1524, ..., 1566) from the DFT / FFT module 1502 are input to the energy estimation module 1504 and the symbol detection module 1506.

The energy estimation module 1504 energizes each of the signal components (1520,1522,1524, ..., 1566) that generate and output the corresponding set of energy values (1528,1530,1532, ..., 1534). Perform the estimation. Each energy estimate corresponds to a different frequency. The symbol detection module 1506 transmits the symbol 1536, eg, a modulated symbol, which is user data, eg, text, audio or video, etc., and / or detects and outputs control data.

The energy values (1528, 1530, 1532, ..., 1534) are input to the threshold determination module 1510 and the threshold energy level detection module 1508. The threshold determination module 1510 includes an averager 1560 and a scaler 1562. The averager 1560 receives energy values (1528, 1530, 1532, ..., 1534) and determines the average energy per frequency of the received signal. The output of the averager 1560 is input to the scaler 1562. The scaler 1562 scales the average energy determined by a factor greater than 4 times, eg, a factor of 5,20,99,150 or higher, depending on the particular embodiment, and produces a threshold level output signal 1538. appear. The threshold level signal 1538 is input to the threshold energy level detection module 1008.

The threshold energy level detection module 1508 compares each of the component energy values (1528, 1530, 1532, ..., 1534) with the threshold level 1538. When one of the energy value components (1528, 1530, 1532, ..., 1534) exceeds the threshold level 1538, the threshold energy level detection module generates and outputs a beacon indicator signal 1540. .. The detection module 1508 also generates and outputs a beacon energy / frequency information signal 1542. The Beacon Energy / Frequency Information Signal 1542 provides information indicating a detected beacon signal component, eg, the frequency of a tone and the detected energy level of that tone.

The beacon index signal 1540 indicating the presence of the detected beacon signal is input to the control module 1512 that triggers the control signal 1544 to the transmitter information determination module 1514 and the control signal 1546 to the network connection point determination module 1516. .. The control signals (1544, 1546), in response to the detected beacon signals, initiate the operation of the modules (1514, 1516), respectively, and control the beacon processing operation.

The transmitter information determination module 1514 contains information about the energy in the beacon signal stored in the energy information 1564, information about the frequency of the detected beacon signal stored in the frequency information 1566, and possible beacons. Information 1568, eg, stored information about the frequency position at which a beacon transmitted by a different network connection point should occur at that frequency position. The transmitter information determination module 1544 receives the beacon energy / frequency information signal 1542, stores the energy level corresponding to the received beacon in the energy information 1564, and the frequency information in the frequency information 1566, eg, Memorize the tone identification, which corresponds to the high energy level. Potential Beacon Information 1568 includes, for example, expected frequency information and / or periodicity information and transmitter information corresponding to the potential beacon. The transmitter information determination module 1514 compares information about the received beacon containing frequency information 1566 with possible beacon information 1568 to provide information about the transmitter that transmitted the beacon signal, eg, sector, cell. , Or the carrier frequency used in the sector or cell from which the detected beacon signal was transmitted. The transmitter information determination module 1514 outputs an information signal corresponding to the beacon signal detected by the network connection point determination module 1516. For example, the output information signal can include power information 1548, frequency information 1550, cell identification information 1552, sector identification information 1554, and / or carrier identification information 1556. In certain embodiments, the plurality of beacon signals transmit different information at different times.

The network connection point determination module 1516 includes a plurality of sets of beacon information (beacon 1 information 1558, beacon n information 1560). Each set of beacon information (1558,1560) corresponds to the received beacon signal, and the determined set of information is power information 1548, frequency information 1550, cell ID information 1552, sector ID information 1554, and carrier ID. Includes information 1556 or at least some of the information derived from information (1548,1550,1552,1554,1556). The network connection point determination module 1516 transmits each set of beacon information (1558,1560) to one network connection point in the communication system, for example, a specific base station sector transmitter using a specific carrier frequency and its corresponding reception. Associate with the machine. The network connection point determination module 1516 provides beacon information for different network connection points (1558, Compare 1560) and make decisions about handoffs from one network junction to another. Various types of handoffs are possible according to the present invention, including cell-to-cell handoffs, sector-to-sector handoffs, and / or carrier-to-carrier handoffs. For example, in one embodiment, the network connection point determination module 1516 may have another network connection point when a beacon associated with another network connection point has a higher energy value than a beacon associated with the current network connection point. Start a handoff request to. Many variations on the handoff determination process are possible according to the present invention. For example, in one embodiment, the beacon energy levels of multiple beacons from one network connection point are filtered over time, eg, average, before comparisons are performed to make handoff decisions. Can be transformed into. In certain embodiments, the margin of difference between the current point-of-point beacon and a possible point-of-point beacon can be measured, and there is a sufficient difference in power level to accept the handoff. It can be compared to the handoff criteria used to determine if it exists. In certain embodiments, the minimum acceptable beacon energy level can be used and considered for handoff determination, for example, beacons below a preselected energy level are handoff. Not considered as a candidate.

Handoff to another network junction in another sector, eg, another network junction in another cell, or another network junction in the same sector that uses different carriers, based on the beacon signal component energy information. When the network connection point determination module 1516 determines that the request is made, the module 1516 sends a connection point selection signal 1562 to the handoff controller 1570. The handoff controller 1570 controls the behavior of the WT with respect to the handoff process. The handoff controller 1570 includes a bandwidth selection controller module 1572. The handoff controller 1570 receives a connection point selection signal 1562, eg, a signal requesting a change of network connection point to a new network connection point corresponding to the detected beacon signal. In response to the change request received, the handoff controller 1570 generates a handoff request signal 1576 directed to the transmitter module of the WT. The handoff request signal 1576 is about to be transmitted as an uplink signal over the current wireless link to the current BS sector network connection point, and the BS sector network selected to act as a new point in the network connection. Transferred to the connection point. For inter-cell handoff requests, the transfer between the current BS sector network connection point and the requested BS sector network connection point is via the backhaul link, while inter-sector inter-cell. For handoff requests or inter-sector carrier handoff requests, forwarding and signaling is internal to the BS.

Included in the detected signal 1536 received is a dedicated resource, eg, a distinguished name used when registering a new network connection point and / or a dedicated uplink segment to the WT, eg. , Allocation signals, such as allocation by requested BS sector network connection point, etc. Allocations are transmitted to the WT over the current established wireless link. A dedicated uplink segment that is going to be used by the WT, for example, a dedicated access segment that is a set of tones during the specified OFDM transmission time interval for the beacon signal corresponding to the requested network connection point. , Used in establishing new wireless links to new network attachment points. For example, in the case of cell-to-cell handoff, a dedicated uplink segment is used to send the uplink timing control signal and / or power control signal that is going to be used by the new BS sector junction. Generates timing and / or power control signals that are about to be sent to the WT to regulate uplink signaling.

The handoff controller 1570 receives a dedicated resource allocation 1574 from the new requested BS sector junction and receives timing and / or data link framing information corresponding to the new sector junction, eg, that information. With respect to information about what type of data the tone is used for during which time slot, and between the beacon associated with the new BS sector junction and the assigned uplink-only segment. When to terminate the previous wireless link using the timing relationship of, or when to switch to the new frequency band assuming that the new BS sector connection point uses a different frequency band from the current BS sector connection point. And when to establish a new BS sector junction and a new wireless link. The band selection controller 1572 generates the band selection signal 1578 at an appropriate time. The band selection signal 1572 is sent to the RF processing module of the single chain receiver to switch bands.

FIG. 16 with a combination of FIGS. 16A and 16B is a flowchart 1600 of a specific example method of operating a wireless terminal (WT), eg, a mobile node such as the WT300, according to the present invention. It can be used in an example orthogonal frequency division multiplexing (OFDM) communication system. The operation begins at step 1602, where the WT is powered on and initialized to receive the downlink signal from the base station. The operation proceeds from step 1602 to step 1604. In step 1604, the WT is operated to receive a signal corresponding to a first frequency band containing multiple tones in the first period of time. The signal contains multiple signal tones, which may or may not carry information, for example, power may not be transmitted on the plurality of tones. The signal tone may include user data, control signals and / or beacon signals. The beacon signal can be transmitted by a transmitter, such as a base station sector transmitter. The base station sector transmitter is a base station sector transmitter that the WT uses as a point of network connection and receives user data from it or from another transmitter. For example, a transmitter that corresponds to an adjacent sector, cell or another carrier frequency within the same sector from which the WT receives user data and acts as the point of WT's current network connection. In that way, while the beacon signal is received in the current frequency band of the WT, it transmits and receives user data, such as text, audio, video, etc., said signal that probably contains the beacon signal. Therefore, it may actually correspond to a transmitter that uses a carrier frequency outside the range of the current frequency band. In certain embodiments, the first time period is the symbol transmission time period. Multiple symbols are included in the signal received in step 1604, eg, one different per tone. May be received in the following tone. The operation proceeds from step 1604 to step 1606.

In step 1606, the WT is operated to perform a time-to-frequency conversion of the received signal to generate a set of signal components corresponding to different signal tones within the first frequency band. The output typically contains one signal component for each tone in the first frequency band, which is used at the very moment of communicating the beacon signal component or the symbol carrying user data or control information. In some embodiments, the WT uses the Discrete Fourier Transform (DFT) in performing the time-to-frequency transform, whereas in other embodiments, the WT performs the time-to-frequency transform. Use the Fast Fourier Transform when doing so.

Next, in step 1608, the WT determines the energy of each of the plurality of different signal components corresponding to different frequencies within the range of the first frequency band, and the energy value per signal tone is different. Generates a set of energy values per signal tone that corresponds to the tone. This can be done using any one of several well-known signal energy measurement techniques. In the case where the beacon detection threshold is dynamically generated from one or more received signals, the operation proceeds from step 1608 to step 1610, which is the threshold generation step. The operation also proceeds from step 1608 to step 1610, where processing of the received signal to detect the presence of the beacon signal is performed.

Step 1612 is an optional step and is used in various embodiments, which use dynamically generated thresholds for the detection of beacon tones. In step 1612, the WT generates one threshold from at least one received signal. Step 1612 includes sub-steps 1614, 1616, 1618, and optionally sub-step 1620. In substep 1614, WT sums the total energy from the set of energy values per signal tone obtained in step 1608. For example, if the first frequency band contains X tones, where X does not have to be all embodiments, but more than 100 in multiple embodiments, the energies of the X tones are together. Is summed to generate an estimate of the total signal energy of the received signal. Then, in substep 1616, the WT divides the determined total energy of step 1614 by the number of tones in the received signal, eg, X, to obtain, for example, the average value of the energy values per tone. .. The operation proceeds from substep 1616 to substep 1618, where the WT produces the result of step 1616 with a coefficient greater than 4 times, eg, 5,6,10,20,100 times or a multiple higher, depending on the means of execution. It works to scale and get a threshold.

In some embodiments, the operation proceeds directly from substep 1618 to step 1610, where the thresholds generated are used. In another embodiment, the operation proceeds from substep 1618 to substep 1620, where the averaging operation is performed. In substep 1620, the WT operates to integrate, eg, average the threshold in step 1618 with the previously generated threshold, to obtain a filtered threshold. In certain such embodiments, the dynamically generated thresholds are generated from a plurality of signals including at least one received signal. The received signal is received in the OFDM symbol transmission time period following the first time period. The threshold output from step 1618 or step 1620 is used in step 1610.

In one embodiment embodiment in which step 1620 is omitted, the dynamically generated threshold is determined to be based on the signal received during the first time period. The first time period is, for example, the same OFDM symbol transmission time period in which the beacon was detected in that period and is not based on the previous OFDM symbol transmission time period.

In some embodiments, the dynamic threshold generation step 1612 is omitted, and step 1610 uses a constant threshold value, eg, a stored value. In some embodiments, the stored constant threshold is one of the plurality of stored thresholds. In one such embodiment, the WT can start operating with the maximum stored value from a set of stored thresholds for a predetermined length of time, and if the beacon If not detected, then the selected stored value for the threshold may be changed, eg, lowered, in steps during the time it takes for the beacon to be detected.

Returning to step 1610, in step 1610, the WT is operated to compare the determined energies of each of the plurality of different signal components to the threshold energy level of the beacon signal. The threshold energy level of the beacon signal is a value determined or preselected in step 1612. The beacon detection threshold is greater than the average value of the signal energy per tone of the received signal. The operation proceeds from step 1610 to step 1622.

At step 1622, the WT determines if any of the comparisons in step 1610 indicate that the threshold level has been exceeded, and the beacon signal component in tones with energy values that exceed the threshold. Indicates that is detected. If the threshold level is exceeded for at least one signal component, the operation proceeds from step 1622 to connection node B1626. However, if the threshold level is not exceeded, the operation proceeds to connection node A1624.

From connection node B1626, the operation continues in steps 1630 and 1632. In step 1630, the WT is operated to identify tones with energy levels that do not exceed the threshold as data / control tones, while in step 1632, the WT contains at least one tone. Tones with energy levels above the threshold are identified as beacon tones. The operation proceeds from step 1630 to step 1634, where tones that do not exceed the beacon threshold are processed.

From connection node A1624, the operation proceeds to step 1628, where the WT is operated to identify the entire set of compared tones as data / control tones. The operation proceeds from step 1628 to step 1634.

At step 1634, the WT is operated to detect an OFDM symbol, eg, an OFDM modulated symbol, contained in said received signal of the identified data / control tone. This typically involves the use of a clock signal, which is synchronized with the symbol timing of the base station that transmitted the data / control tone, for example, the clock is synchronized with the point of the current network connection. The data / control tone can transmit user data, power control channel information, timing control information, allocation information, and / or receipt notification information. User data originates from another WT, and the receiving WT has a communication session with that WT over a point of network connection.

Returning to step 1632, the operation proceeds from step 1632 to step 1636, where the WT is operated to generate a beacon signal or an indicator signal indicating the presence of a plurality of beacon signals. The operation proceeds from step 1636 to step 1638. At step 1638, the WT is operated to store information about the determined energy and frequency corresponding to the identified beacon tone. In step 1640, the WT determines the carrier frequency corresponding to the detected beacon signal, for example, based on the frequency of the beacon signal. Moreover, the sector ID and the cell ID can be determined from the frequency corresponding to the beacon tone. The operation proceeds from step 1640 to step 1642. In step 1642, the identified beacon tone and the determined identification information corresponding to the received signal are stored. The operation proceeds from step 1642 to step 1644 and step 1646. Beacon signal detection and determination is essentially based on the components of the received beacon or multiple components, such as the frequencies of multiple tones and / or the interval at which the beacon signal is received at that interval on a particular frequency. , Transmitter information can be obtained from the beacon signal without the need for the WT to achieve or maintain symbol timing synchronization with the transmitter of the beacon signal.

At step 1644, the WT is operated to begin processing another signal at the next time interval, eg, the symbol transmission period. The operation proceeds from step 1644 to step 1604 via connection node C1650, for example, for receiving and processing the next received signal during the next OFDM symbol interval.

In step 1646, is at least two beacon signals detected and is information stored corresponding to different transmitters, eg, multiple transmitters within one sector using different cells, sectors, or different carrier frequencies? WT is activated to check. If a beacon corresponding to another transmitter is detected, the operation proceeds to step 1648, where the WT points the network connection based on a comparison of the energies associated with the signal components corresponding to the different detected beacons. It is operated to determine which base station sector to use as. For example, in step 1648, the WT can select the connection point corresponding to the beacon associated with the maximum energy level. Selection may require various handoff criteria to prevent frequent and / or unnecessary switching between multiple carriers. For example, the power level of the beacon signal component or components related to the particular connection point under consideration is pre-selected before a network connection point is selected that is different from the current network connection point. It may be necessary to exceed the power level of the beacon signal associated with the point of connection of another network for a set amount of time.

The operation proceeds from step 1648 to step 1650, where the selected point of the network connection is compared with the current point of the network connection. If not, it indicates the need for a handoff and the action proceeds to step 1652, where the WT begins the handoff at the newly selected connection point. In certain embodiments, it sends one or more signals to the point of connection of the new network through the point of connection of the current network and one or more dedicated wireless links. Includes receiving resources through a point of connection in the current network.

Assuming that the new network connection point uses a different carrier frequency than the current network connection, the operation proceeds from step 1652 to step 1654, where WT renews its receiver frequency band and transmitter frequency band. Switch to the frequency band of the network connection point. The operation proceeds from step 1654 to step 1644. If the frequency band at the new network connection point is the same as the frequency band at the old network connection point, no change in the WT frequency band is required, and step 1654 is omitted and the operation proceeds from step 1652 to step 1644.

Throughout the time, based on the beacon signal received, the selection of network connection points will be based on network connection points and carrier frequencies as the signal state changes, for example due to WT repositioning or other conditions. It is re-evaluated by repeating the switching of WT between.

In some embodiments, which may not be all, the beacon signal tone is 10 of the average signal energy per tone of the signal tone used to transmit user data and / or non-beacon control signals. It is transmitted with signal energy per tone that is a multiple, 20x, 30x, or higher multiple. In the case of signal tone beacon signals, the frequency of the beacon signal can be easily determined from the frequency of the signal high power tones forming the beacon signal.

The selection between multiple carriers has been described as being based on a comparison of the energies detected in multiple beacon signals received from two different beacon transmitters, but this comparison corresponds to the first transmitter. To average the power of the beacon signal received from the transmitter over time to generate the average received beacon power, and then another one average received beacon power corresponding to the second transmitter. Can be included. These two mean values were then compared to determine which beacon signal was stronger on average over one period of time, and then determined to be a stronger beacon signal over multiple time periods. Select the carrier involved in the beacon signal. Alternatively, the total beacon signal power can be integrated over time and then compared to beacon signals received from different transmitters. In each of these cases, the choice of carrier frequency should be based on a comparison of the energies received in one or more beacon signals from another transmitter.

Although described primarily in the context of OFDM systems, the methods and devices of the invention are applicable to a wide range of communication systems, including many non-OFDM and / or non-cellular systems.

In various embodiments, the nodes described herein are given using one or more modules and the steps corresponding to one or more methods of the invention, eg, carrier bandwidth. Perform selection, digital signal processing, energy detection / SNR detection, decoding, timing synchronization, signal quality detection, etc. In certain embodiments, the various features of the invention are implemented using multiple modules. Such modules can be run using software, hardware, or a combination of software and hardware. Many of the methods or steps of methods described above are general purpose with or without machines, eg, additional hardware, to perform all or part of the methods described above, eg, on one or more nodes. To control a computer, using a memory device, eg, a machine-executable instruction such as software contained in a machine-readable medium such as RAM, Floppi Disk®, etc. Can be executed. Thus, among others, the present invention uses machines, such as processors and related hardware, to perform one or more steps of the methods described above. Aimed at a machine-readable medium that contains machine-executable instructions to operate.

Many further modifications of the methods and devices of the invention described above will be apparent to those skilled in the art in light of the above description of the invention. Such modifications should be considered within the scope of the present invention. The methods and devices of the present invention, and in various embodiments, CDMA communication technology, Orthogonal Frequency Division Multiple Access (OFDM) communication technology, and / or various other types of communication technology, which comprises multiple access. It can be used with, which can be used to provide a wireless communication link between a node and a mobile node. In certain embodiments, the access node is provided as a base station that establishes a communication link with a mobile node using OFDM and / or CDMA. In various embodiments, the mobile node is a notebook computer, personal data assistant (PDA), or receiver / transmitter circuit and logic element and / or routine for performing the methods of the invention. Runs as other portable devices, including. <u style="single">The inventions described in the claims of the original application of the present application are described below.</u><u style="single">[1] A communication method for use in a wireless terminal in an OFDM communication system, the method comprising:</u><u style="single"> Receiving the first signal within the first frequency band, said first signal contains multiple signal tones, each signal tone corresponding to a different frequency;</u><u style="single"> Performing a time-to-frequency conversion on the received signal to generate a set of signal components corresponding to different signal tones within the first frequency band;</u><u style="single"> Determining the energy of each of a plurality of different signal components corresponding to different signal tones within the first frequency band to generate one set of energy values per signal tone, the energy per signal tone Values correspond to different frequencies;</u><u style="single"> Detecting the signal component corresponding to the beacon signal from the energy value per tone of the signal component;</u><u style="single"> To determine the carrier frequency corresponding to the beacon signal based on the frequency of the signal component detected as corresponding to the beacon signal.</u><u style="single">[2] Communication method of [1] above,</u><u style="single"> Here, the carrier frequency corresponding to the beacon signal is different from the current carrier frequency used to communicate with the connection point of the current network;</u><u style="single"> Here, the carrier frequency corresponding to the beacon signal is within a second frequency band used to transmit user data by the point of connection of the network that transmitted the detected beacon signal component. The detected beacon signal component is located outside the range of the second frequency band.</u><u style="single">[3] The method of [1] above, which further comprises:</u><u style="single"> Making a handoff determination as a function of the amount of energy contained in at least one beacon signal component received from the point of connection of the current network and the amount of energy contained in the detected beacon signal component. , The detected beacon signal component is transmitted by a network connection point different from the current network connection point.</u><u style="single">[4] The method of [1] above, wherein the signal component corresponding to the beacon signal is detected from the signal energy value per tone of the signal component includes the following:</u><u style="single"> Vs. large threshold energy level than the signal energy of the per average tone of the received signal that was to compare the detected energy of each of said plurality of different signal components.</u><u style="single">[5] The method of [4] above, wherein the threshold energy level is at least N times the signal energy per tone of the average received first signal within the first frequency band. And here N is a positive number greater than 5.</u><u style="single">[6] The method of [4] above, wherein the threshold energy level is at least N times the signal energy per tone of the average received first signal within the first frequency band. And here N is a positive number greater than 20.</u><u style="single">[7] The method of [4] above, wherein the threshold energy level is at least N times the signal energy per tone of the average received first signal within the first frequency band. And here N is a positive number greater than 99.</u><u style="single">[8] The method of [4] above, wherein the threshold energy level is at least N times the signal energy per tone of the average received first signal within the first frequency band. And here N is a positive number greater than 150.</u><u style="single">[9] The communication method of [4] above, wherein the step of performing the time-to-frequency transform uses one of the Discrete Fourier Transform (DFT) and the Fast Fourier Transform (FFT). Will be executed.</u><u style="single">[10] The method of [6] above, which further comprises:</u><u style="single"> Responding to detecting the presence of a signal component corresponding to a beacon signal that determines at least one of a sector ID and a cell ID based on the frequency of the signal component above the threshold.</u><u style="single">[11] The method of [10] above, wherein the received symbol is received during the first period of time, which is the symbol transmission time period.</u><u style="single">[12] The method of [11] above, which further comprises the following steps:</u><u style="single"> Detecting the OFDM symbol contained in the first received signal for a tone that does not have an energy level above the threshold.</u><u style="single">[13] The method of [4] above, wherein the threshold is a dynamically generated threshold, further comprising:</u><u style="single"> Generate the threshold from at least one received signal.</u><u style="single">[14] The method of [13] above, wherein the at least one received signal comprises a plurality of tones, and the step of generating the threshold includes:</u><u style="single"> To determine the energy per tone of the at least one received signal.</u><u style="single">[15] The method of [14] above, wherein the energy per tone corresponds to the total energy of the at least one received signal divided by the number of different tones contained in the at least one received signal. However, each tone corresponds to a different frequency.</u><u style="single">[16] The method of [13] above, wherein the at least one received signal is a signal received at the OFDM symbol transmission time prior to the first time period in which the first signal is received. ..</u><u style="single">[17] The method of [13] above, where the at least one received signal is the first received signal.</u><u style="single">[18] The method of [4] above, which further comprises:</u><u style="single"> To store information about the determined energy and frequency of the first signal component in the received signal determined to have a signal component energy level above the threshold energy level.</u><u style="single">[19] The method of [18] above, wherein the first signal component is a base station sector transmitter corresponding to the base station sector in which the wireless terminal performing the receiving step is located. Received from.</u><u style="single">[20] The method of [18] above, wherein the first signal is received in the first period of time, further comprising:</u><u style="single"> Receiving a second signal in the second period of time, said second signal contains multiple signal tones, each signal tone in said second signal corresponds to a different frequency;</u><u style="single"> Performing a time-to-frequency conversion on the received second signal to generate a second set of signal components corresponding to different signal tones within the first frequency band;</u><u style="single"> Determining the energy of each of a plurality of different signal components in the second set of signal components to generate a second set of energy values per signal tone, the second set of energy values per signal tone. The energy value per signal tone in the set corresponds to a different frequency;</u><u style="single"> Comparing the determined energies of each of the plurality of different signal components with respect to the threshold energy level;</u><u style="single"> Generating a second indicator signal indicating the presence of a second beacon signal when the comparing step determines that the threshold energy level has been exceeded.</u><u style="single">[21] The method of [19] above, which further comprises:</u><u style="single"> Which base to use as a point of network connection based on a comparison of the determined energy of the first signal component with the determined energy of the signal component in the determined second signal. Determining if a station sector has an energy level above the threshold energy level.</u><u style="single">[22] The method of [1] above, where the current network connection point is the first sector of the cell, where the detected beacon signal is transmitted by another sector of the cell. Will be done.</u><u style="single">[23] The method of [1] above, where the current network connection point is the first sector of the cell, where the detected beacon signal is transmitted by different sectors of different cells. To.</u><u style="single">[24] The method of [1] above, where the current network connection point is the first module corresponding to the first carrier used in the first sector of the cell, and here described above. The detected beacon signal is transmitted by the second module corresponding to the second carrier used in the first sector of the cell, and the second module is the first in the first sector of the cell. Functions as a network connection point for 2.</u><u style="single">[25] Wireless terminals for use in OFDM communication systems, said wireless terminals include:</u><u style="single"> Means for receiving a signal in the first period of time, said signal contains multiple signal tones, each signal tone corresponding to a different frequency;</u><u style="single"> A means for performing a time-to-frequency conversion of the received signal to generate a set of signal components corresponding to different signal tones within the first frequency band;</u><u style="single"> A means for determining the energy of each of a plurality of different signal components corresponding to different frequencies within the first frequency band to generate one set of energy values per signal tone, per signal tone. Energy values correspond to different frequencies;</u><u style="single"> Each of the plurality of different signal components was determined for a threshold energy level greater than the energy per signal tone of the received signal to detect the signal component corresponding to the beacon signal. Means for comparing energies; and</u><u style="single"> To a network connection point that uses a carrier frequency to transmit the detected beacon signal and user data that is different from the carrier frequency being used by the wireless terminal to communicate with the current network connection point. A means to determine if a handoff should be initiated.</u><u style="single">[26] The wireless terminal of [25] above, wherein the threshold energy level is at least N times the energy per signal tone of the average signal of the received signal in the first frequency band. , Where N is a positive number greater than 5.</u><u style="single">[27] The wireless terminal of [25] above, wherein the threshold energy level is at least N times the average signal energy of the received signal in the first frequency band, where. , N is a positive number greater than 150.</u><u style="single">[28] The wireless terminal of [25] above, wherein the means for performing the time-to-frequency transform uses one of the Discrete Fourier Transform (DFT) and the Fast Fourier Transform (FFT). Is executed.</u><u style="single">[29] The wireless terminal of [28] above, said wireless terminal further comprises:</u><u style="single"> A means for determining at least one of a sector ID and a cell ID based on the frequency of the signal component above the threshold.</u><u style="single">[30] The wireless terminal of [29] above, where the first period of the time is the OFDM symbol transmission time period.</u><u style="single">[31] The wireless terminal of [30] above, said wireless terminal further comprises:</u><u style="single"> A symbol detection module that detects symbols contained in the received signal for tones that do not have an energy level above the threshold.</u><u style="single">[32] The wireless terminal of [25] above, where the threshold is a dynamically generated threshold, the wireless terminal comprises:</u><u style="single"> A threshold generation module connected to the means for performing a time-to-frequency conversion.</u><u style="single">[33] The wireless terminal of [25] above, said wireless terminal further comprises:</u><u style="single"> Stores information about the determined energy and frequency of the first signal component received during the first period of time determined to have a signal component energy level above the threshold energy level. Means to do.</u><u style="single">[34] The wireless terminal of the above [33], wherein the first signal component is a base station sector transmission corresponding to a base station sector in which the wireless terminal performing the receiving step is located. Received from the machine.</u><u style="single">[35] The wireless terminal of [33] above,</u><u style="single"> Here, most of the energy contained in the first signal component is located adjacent to the base station sector in which the wireless terminal receiving the first signal component is located. Received from the base station sector corresponding to the base station sector.</u><u style="single">[36] The wireless terminal of [33] above, said wireless terminal further comprises:</u><u style="single"> Means for receiving a second signal in the second period of time, said second signal contains multiple signal tones, each signal tone in said second signal corresponds to a different frequency;</u><u style="single"> A means for performing a time-to-frequency conversion of the received second signal to generate a second set of signal components corresponding to different signal tones within the first frequency band;</u><u style="single"> A means for determining the energy of each of a plurality of different signal components in said second set of signal components to generate a second set of energy values per signal tone, said The energy values per signal tone in the second set correspond to different frequencies;</u><u style="single"> Means for comparing the determined energy of each of the plurality of different signal components with respect to the threshold energy level; and</u><u style="single"> A means of deciding whether a handoff should be initiated.</u><u style="single">[37] The wireless terminal of [34] above, said wireless terminal further comprises:</u><u style="single"> Which base to use as a point of network connection based on a comparison of the determined energy of the first signal component with the determined energy of the signal component in the determined second signal. A means for determining whether a station sector has an energy level above the threshold energy level.</u>