Method and apparatus for time-division power assignments in a wireless communication system

Method and device for time division power distribution in wireless communication system

The features, objectives, and advantages of the methods and devices disclosed in this article will be clear and easy to understand from the following detailed description and together with the drawings. In all the drawings, the same reference numbers represent the same elements and in the corresponding manner. in:

Figure 1 is a ground base station configured according to a specific example;

Figure 2 illustrates a sector that is subdivided according to one of a specific example;

Figure 3 shows the sectoral partition beams alternately generated according to a fixed time slot;

Figure 4 is a flow chart of a method illustrating a method of increasing system energy and data rate by means of the carrier-to-interference ratio (C/I) measured at the user station;

Figure 5 is a block diagram of a base station device configured according to an example;

Figure 6 is a diagram of a part of a CDMA reverse link subscriber station device configured according to a specific example;

FIG. 7 is a diagram of a cell in a CDMA communication system, illustrating the division of time slots in three (3) sectors according to an example; and

FIG. 8 is a schematic diagram of a balance circuit in a receiver having a CDMA communication system as shown in FIG. 7. FIG.

Reference materials related to the application in the same application procedure. This patent application is related to the patent application in the same application procedure named "Method and Apparatus for Wave Exchange in a Wireless Communication System". This application The case was filed by Ahmad Jalali and others. Its agent file number is PA000331, and the filing date is June 29, 2000. This patent application was assigned to the assignee of this case.

scope

The present invention relates to wireless data communication. More specifically, the present invention relates to novel and improved methods and devices for time-division power distribution in wireless communication systems.

background

Modern communication technology requires that it can support a variety of different purposes. One of the communication systems is the Code Division Multiple Access (CDMA) system, which complies with the "TIA/EIA/IS-95 Mobile Station-Base Station Compatibility Standard for Dual Wideband Scrambling Cellular Systems". It is called IS-95 standard in the text. The CDMA system allows users to engage in voice and data communications via terrestrial links. In the multiple access communication system, the use of CDMA technology is disclosed in U.S. Patent No. 4,901,307 under the name "Spread Spectrum Multiple Access Communication System Using Satellite or Terrestrial Transponder" and in U.S. Patent No. 5,103,459. The name is "System and Method for Waveform Generation in CDMA Cell Phone System", both of these patents are assigned to the assignee of the present invention and both of them are expressly incorporated herein by reference.

In this manual, the base station refers to the hardware used by the user station for communication. Cells refer to areas covered by hardware or geographically, depending on the environment in which the term is used. A sector is a division of a cell. A sub-sector is a partition of a sector. Since a sector and a sub-sector in a CDMA system have the attributes of a cell, the description of the cell can be extended to describe the sector and the sub-sector.

In the CDMA system, communication between users is implemented via one or more base stations. A first user on a user station and a second user on a second user station communicate by sending data to a base station on a reverse link. The base station receives the data and can send the data to another base station via a route. This data is sent to the second user station on the same base station or on the forward link of a second base station. The forward link refers to transmission from the base station to the user side, and the reverse link refers to transmission from the user station to the base station. However, in the IS-95 system, the forward link and the reverse link are assigned separate frequencies.

The user station communicates with at least one base station during the communication period. The CDMA user station can communicate with multiple base stations at the same time during the soft handover. Soft handover is the process of establishing a link with a new base station before cutting the link with the previous base station. Soft handover can minimize call missed. A method and system for providing communication with one user station via more than one base station in the soft handover process is disclosed in US Patent No. 5,267,261, which is titled "Assisted Mobile Soft Handover in CDMA Cellular Phone System" Pass", this patent has granted the present invention and is expressly incorporated herein by reference. Softer handover is a communication process that occurs in multiple sectors served by the same base station. This softer handover process is described in detail in U.S. Patent No. 5,625,876. This patent is titled "Method and Apparatus for Handover between Sectors of Shared Base Stations". This patent is granted to the assignee of the present invention. Renhe is specifically incorporated into this article by reference.

As the demand for wireless data applications is increasing, the importance of the need for highly effective wireless data communication systems is also increasing. The IS-95 standard can send data communication and voice communication via the forward and reverse links. A method for sending data communication with a fixed-size code channel frame is described in detail in US Patent No. 5,504,773. The title of this patent is "Method and Device for Data Transmission and Formatting". This patent is granted to the subject of the present invention. Let people and deliberately incorporate into this article by reference. According to the IS-95 standard, data communication or voice communication is divided into code channel frames with a width of 20 milliseconds and a data rate of up to 14.4 kbps.

It is recommended to use high data rate standards for the transmission of high-rate data communications and voice communications on the forward and reverse links. According to the recommended high data rate standard, data communication or voice communication is divided into time slots of different widths. A code channel frame includes 1 to 16 time slots. The beamforming technology used to reduce the interference caused by the transmission from a base station to several user stations in a neighboring cell is described in detail in U.S. Patent Application No. 09/388,267, which was published on September 1, 1999 An application was filed on Japan, whose name is "Method and Apparatus for Forming Beams in Wireless Systems", which was granted to the assignee of this case and is specifically incorporated herein by reference.

One of the important differences between voice services and data services is that semantic services have strict and fixed delay requirements. Generally speaking, the overall one-way delay of the speech frame must be less than 100 milliseconds. In contrast, the data delay can be a variable parameter used to optimize the efficiency of the data communication system. Specifically, a more effective error correction coding technique can be used, which requires a much larger delay than the voice service can withstand. An exemplary effective coding design for data use was disclosed in U.S. Patent Application No. 08/743,688. The title of this patent application is "Soft Decision Output Decoder for Decoding Codewords Encoded in Convolutional Mode". This application was filed on November 6, 1996 and is specifically incorporated herein by reference.

Another important difference between voice service and data service is that a fixed and shared service level (GOS) is required for all users. In general, for digital systems that provide voice services, this service level is converted into a fixed and equal emissivity for all users and a maximum allowable value for the error rate of the voice frame. In contrast, for data services, this GOS is different from customer to customer and can be an optimized parameter to increase the overall performance of the data communication system. The GOS of the data communication system is generally defined as the delay incurred in the transmission of a predetermined amount of data. This predetermined amount of data is referred to as a data packet in the following text.

Another important difference between voice services and data services is that voice services require a reliable communication link, which is provided by soft handover in an exemplary CDMA communication system. Soft handover results in redundant transmission from two or more base stations to improve reliability. However, this additional reliability is not necessary for data transmission, because data packets received in a wrong way can be retransmitted. For data services, the transmit power used to support soft handover can be used to transmit additional data in a more effective manner.

The parameters for measuring the quality and performance of a data communication system are the transmission delay required to transmit data packets and the average transmission rate of the system. The impact of transmission delay on data communication is not the same as its impact on voice communication, but it is an important measure of the quality of data communication systems. The average transmission rate is a measure of the efficiency of the data transmission capability of a communication system.

In a cellular system, the carrier-to-interference ratio (C/I) of any user is a function of the user's location in the coverage area, which is well known. In order to maintain a predetermined level of service, TDMA and FDMA systems adopt frequency reuse technology, which means that not all channels and/or time slots are used at each base station. In a CDMA system, the same frequency allocation is reused in each cell of the system, thereby improving overall efficiency. The C/I reached by the user station of any specific user can determine the information rate that can be supported by the user station from the base station to the user. When a dedicated modulation and error correction method for transmission is available, a predetermined performance level can be achieved at a corresponding C/I level. For an idealized cellular system that has a hexagonal cellular configuration and uses a common frequency for each cell, the C/I distribution achieved in an ideal cell can be calculated. A demonstration system for transmitting high-rate digital data in a wireless communication system is disclosed in US Patent Application No. 08/963,386, which is titled "Method and Apparatus for Data Packet Transmission at Higher Rate" , (This case is referred to as the '386 application in the following text), which was filed on November 3, 1997. This application was granted to the assignee of this application and is specifically incorporated herein by reference.

It is also well known that many signal interferences in the loaded CDMA system are caused by transmitters belonging to the same CDMA system. In efforts to increase energy and data rate by reducing interference, cells are often divided into sectors or smaller cells that operate at lower power. However, the signal method is expensive and difficult to apply to areas with widely varying signal propagation characteristics. Traditional methods generally have poor signal quality near the boundary. There is now a need for a simplified method that can reduce the mutual interference between components in the system and increase the system energy and data rate at the same time.

Overview

The specific example disclosed in this paper provides a novel and improved method for enhancing the energy and database of a CDMA data communication system by using the maximum value of the carrier-to-interference ratio (C/I) measured at the user station. The beam switching technology is used to reduce the interference caused by the transmission from a base station to the user stations in a cell and its neighboring cell sectors. The base station uses multiple transmitting antennas, and each transmitting antenna transmits a signal with a controlled amplitude and phase to form a transmission signal beam corresponding to a sector or sub-sector. The data and reference signals are transmitted along the sector-zoned beams, and the cut-off beams alternately appear according to a fixed time slot so as to concentrate energy at the user station without interference from adjacent beams.

Therefore, one feature of the present invention is to provide a method for adjusting the signal power used to transmit data to each sector during a set time slot, wherein the power level for a set sector is through continuous time slots. The available power level rotates.

According to one feature of the present invention, a method of communication in a wireless communication system. The system has a first cell and a plurality of sectors in the cell. The method includes adjusting the first power level during the first time slot. The signal is transmitted to the first sector and the signal of the second power level is transmitted to the second sector during the first time slot.

According to another feature of the present invention, a mobile unit includes an antenna and a balancer coupled to the antenna. The balancer additionally includes multiple taps or amplifiers, a summing node and a memory storage unit. Each amplifier has first and second correlation coefficients. The first correlation coefficient corresponds to the first time slot. During the first time slot, multiple amplifiers use the first correlation coefficient to scale the first group of input symbols. During the second time slot, two amplifiers use the second correlation coefficient to scale the second set of input symbols, and these multiple amplifiers additionally generate amplifier outputs. The summing node is coupled to multiple amplifiers, and the function of the summing node is to add the outputs of the amplifiers. The function of the memory storage unit is to store the coefficient adjustment information, and the correlation coefficient is adjusted according to the coefficient adjustment information.

According to another feature of the present invention, a balancer includes a plurality of amplifiers and a coefficient adjustment node. The function of the amplifier is to use the first set of correlation coefficients during the first time slot and the second set of correlation coefficients during the second time slot to calibrate the first set of phase relationships. The coefficient adjustment node is coupled to a plurality of amplifiers, and the function of the coefficient adjustment adjustment point is to apply the first set of correlation coefficients during the first time slot and the second set of correlation coefficients during the second time slot.

According to another feature of the present invention, a mobile unit includes a balancer for calculating a first energy estimate of the signal power of the first transmission and a second energy estimate of the signal power of the second transmission, and a data rate determination The node is used to receive the energy estimate value from the balancer and generate a first data rate decision for the first energy estimate value and a second data rate decision for the second energy estimate value.

According to another feature of the present invention, a mobile unit for high-speed data communication with at least one base station includes an encoder configured to receive data packets having a first signal power during a first time slot , And receive a data packet with the second signal power during the second time slot, and include a data rate control encoder, which is configured to generate in response to the channel condition information derived from the received data packet The data rate control message is encoded for transmission during the first and second time slots.

Schematic description

The features, objectives, and advantages of the methods and devices disclosed in this article will be clear and easy to understand from the following detailed description and together with the drawings. In all the drawings, the same reference numbers represent the same elements and in the corresponding manner. in:

Figure 1 is a ground base station configured according to a specific example;

Figure 2 illustrates a sector that is subdivided according to one of a specific example;

Figure 3 shows the sectoral partition beams alternately generated according to a fixed time slot;

Figure 4 is a flow chart of a method illustrating a method of increasing system energy and data rate by means of the carrier-to-interference ratio (C/I) measured at the user station;

Figure 5 is a block diagram of a base station device configured according to an example;

Figure 6 is a diagram of a part of a CDMA reverse link subscriber station device configured according to a specific example;

FIG. 7 is a diagram of a cell in a CDMA communication system, illustrating the division of time slots in three (3) sectors according to an example; and

FIG. 8 is a schematic diagram of a balance circuit in a receiver having a CDMA communication system as shown in FIG. 7. FIG.

Detailed description of preferred concrete examples

The specific examples disclosed herein improve the efficiency of the CDMA system by providing a strong forward link signal to a destination subscriber station, while at the same time generating minimal interference to other subscriber stations. The specific examples disclosed provide a way to maximize the energy in high data rate wireless systems by modifying the fixed beam switching technology used in terrestrial wireless devices. A cellular system with multiple transmitting antennas at each base station according to one of the disclosed specific examples will now be described. Each antenna of each base station transmits the same signal, but each signal has a different relative phase shift and power level in order to concentrate energy in a sub-sector, that is, where a user station in a sector is located In the part. In order to maximize the carrier-to-interference (C/I) ratio of the desired signal receiver (usually a single user station), the amplitude and phase of the signal transmitted from each transmitting antenna must be appropriately set.

Any signal quality metric based on the estimated C/I value can be used by the user station as a feedback to the base station. In the exemplary high-data-rate wireless communication system described in the '386 application, the user station determines the data rate at which data packets are successfully received based on its estimated C/I value. This data rate is sent to the base station with a data rate control (DRC) signal instead of the C/I measurement value. This DRC information is embedded in the signal sent from the subscriber station to the reverse link. The base station can also use the change of the DRC signal to determine the time slot during which data is transmitted to the user.

Traditionally, a single beam is transmitted in a sector covering the entire sector, regardless of the location of the receiver in this sector. If a single beam cannot be received by its user station, its energy will be wasted and it will interfere with other users. The specific example disclosed in this paper divides the sector into sub-sectors and transmits fixed beams directly to each sub-sector where the user station is located, and alternates between non-adjacent sub-sectors to reduce interference, so that the user station is The carrier-to-interference ratio has a maximum value.

Figure 1 shows a diagram of a ground base station configured as a three-sector cell. The cell 100 includes three sectors 102, 104, 106. In the specific example illustrated, a base station 108 is located in each sector of the cell 100. In another specific example, a single base station can serve two or more sectors in a cell. The base station 108 transmits fixed beams via four transmitting antennas 110. Although each base station 108 is shown to have four transmitting antennas 110, the specific example disclosed is generally applicable to a base station having one or more transmitting antennas, including one transmitting antenna using a directional antenna array. In addition, those skilled in the industry will be able to understand that different types and polarized antennas can be used, including omnidirectional and directional antennas. In addition, an antenna used to transmit from a base station can be of a different type than other antennas used by the same base station.

The antenna element 110 forms a phased array for each sector 102, 104, 106, and this array generates a number of fixed beams for each sector 102, 104, 106. In the specific example shown in the figure, each sector 102, 104, 106 has 4 fixed beams. The signals transmitted through multiple antennas of a single base station 108 are preferably identical, but may differ in transmission amplitude and phase. When transmitting a signal, the base station 108 adjusts the amplitude and phase of the signal transmitted via the antenna 110. To form a fixed signal beam directed to the fixed sub-sectors or sub-sectors of the sectors 102, 104, 106 served by the base station 108.

Generally speaking, the use of beam switching to transmit to a base station 108 of a sub-sector will cause less interference to user stations in neighboring sub-sectors than a base station 108 that transmits via a single antenna to the entire sector 102, 104, 106. The interference caused.

Figure 2 illustrates an exemplary unit 200 including one of three sectors 202, 204, 206. The figure shows a sector 204 divided into 4 sub-sectors 0207, 1209, 2211, and 3213. Each sub-sector 207, 209, 211, 213 is respectively covered by a fixed transmitting beam 208, 210, 212, 214 generated by the antenna element of the base station (not shown in the figure) serving the sector 204. An advantageous way is that the alternate sub-sectors 207, 209, 211, 213 are designated as even or odd. Sub-sectors 0207 and 2211 are designated as even-numbered sub-sectors, and sub-sectors 1209 and 3213 are designated as odd-numbered sub-sectors. The data transmission slot is also preferably designated as an even number and an odd number. The sub-sector transmit beams 208, 210, 212, 214 remain fixed regardless of the position of the user station 216 in the sector 204. The user station 216 selects the best beams 208, 210, 212, 214 by measuring the C/I value of the current guide. In the disclosed system, the transmitter is a CDMA signal, and the transmission of a base station serving other user stations and cell areas in it often causes the main interference suffered by a receiving user station 216. In the specific example disclosed, each user station 216 implements an estimation of the C/I or carrier-to-interference ratio. The resulting C/I measurement information is transformed into a data rate control (DRC) signal. Then this DRC, instead of the C/I measurement value, is transmitted from each user station 216 to its serving base station. The base station transmits at a fixed power, but the data rate used for transmission to each user station 216 is changed according to the DRC information received from the user station 216. The user station 216 performs C/I measurement to send the DRC information of its base station to select the data rate for transmission on the forward link. If the interference value to the user station 216 is large, the base station transmits at a low data rate. Conversely, if the interference to the user station 216 is small, the user station 216 transmits at a high data rate.

In the traditional cellular communication system, the interference to the user station 216 is greater at the boundary between the cell and the sector where the beam overlaps. Traditionally, a user station 216 located at the boundary of a sub-sector will communicate with any sub-sector transmit beam, but adjacent beams will interfere with each other and make C/I a low value. The specific example disclosed uses a simple method of alternately transmitting even-numbered 208,212 and 210,214 sub-sector beams during odd and even time slots to eliminate interference at adjacent sub-sector boundaries. During even time slots, only even beams 208, 212 are transmitted. During even time slots, the amplitude and phase coefficients of the odd signal beams 210 and 214 are set to zero. During the odd-numbered transmission slot, only odd-numbered beams 210 and 214 are transmitted. During the odd transmission time slot, the amplitude and phase coefficient of the even signal beams 208 and 212 are set to zero. Eliminating interference (I) increases C/I, thereby increasing system energy and data rate. The alternate beam switching method of the disclosed specific example, even with the transmission of 6 sub-sectors of a 12-sector cell during the same set time slot, has an operating performance compared to the traditional 6-sector cell configuration with boundary interference. The one is better. The alternate beam switching method of the disclosed specific example can enable the user station 216 located near the boundary to have good received signal quality, so that the user station 216 can request a higher data rate.

Those skilled in the art will understand that a cell can be divided into several sectors arbitrarily, or sectors and sub-sectors can be arranged in any manner without departing from the scope of the present invention.

3A, B, and C are timing diagrams, for example, fixed sub-sector partition beams that alternately occur according to a fixed transmission time slot. FIG. 3A shows an example of even-numbered time slots activated and deactivated odd-numbered time slots at a set time. FIG. 3B shows the base station transmitting on even-numbered beams 0 and 2 during the set time slot for even-numbered transmission. FIG. 3C shows the base station transmitting on odd beams 1 and 3 during the set even-numbered transmit time slot.

The disclosed specific examples can identify even and odd transmission time slots corresponding to even and odd sub-sector transmission beams in an advantageous manner. The even-numbered signal beam is only emitted during the even-numbered transmission slot. The odd-numbered signal beam is only emitted during the odd-numbered transmission time slot. During any set time slot, half of the sub-sector transmit beams will be activated, and the other half of the transmit beams will be deactivated. The interference from adjacent transmit beams can be eliminated using the alternate beam switching method of the disclosed specific example.

The base station uses the DRC messages received from the user stations to maintain the knowledge of the user stations located in the area covered by their sub-sectors. The same signal is transmitted to all sub-sectors in a sector. The complicated tracking method and smart antenna design required to improve C/I can be eliminated by simplifying the specific examples disclosed.

Figure 4 illustrates the method steps according to a specific example. As mentioned above, the system energy and data rate are increased if the C/I measured at the user station has the maximum value. C/I uses a beam switching method to get the maximum value.

In step 402, the odd-numbered sub-sector beams are transmitted from the base station via the forward link during the odd-numbered time slots. The user station (not shown in the figure) receiving the data receives a data packet during the odd transmission time slot, and generates a DRC based on the C/I of the received data. There is a pilot signal or a series of known pulse signals in each transmission time slot, which is transmitted on the forward link. The user station uses the pilot signal to predict the C/I of the data to be received in the next time slot. Based on this estimated C/I, the user station determines the data rate it can support. For a set C/I, the data rate that the user station can support has a maximum value. The user station uses the pilot signal transmitted in each activation time slot and uses a check table to find the maximum data rate, thereby predicting the C/I in the subsequent activation slot.

In step 404, during the even-numbered transmission slot, the user stations receiving the data generate a DRC during the reverse-link odd-numbered slot, and then go to their base station via the reverse link. In each odd-numbered time slot, the user stations that receive data during the even-numbered transmission slot send a DRC message to their base station, indicating their receivable data rate, and the base station then uses the indicated during the next even-numbered time slot The rate is sent to the user station.

In step 406, the even-numbered sub-sector beams are sent by the base station via the forward link during the even-numbered time slots. The user station receiving the data receives a data packet during the even-numbered transmission slot and generates a DRC signal according to the received C/I.

In step 408, the user stations that receive data during the odd-numbered transmission time slots send a DRC to their base stations via the reverse link during the even-numbered time slots of the reverse link. In each even-numbered time slot, the user station receiving data sends a DRC message to their base station during the odd-numbered transmission slot to indicate the data rate at which it can receive. The base station transmits to the user station at the indicated rate in the next odd time slot.

FIG. 5 is a block diagram showing an exemplary specific example for transmitting alternate sub-sector beam signals to a CDMA base station of one or more user stations via multiple transmitting antennas. In the proposed third-generation CDMA system, the signal is modulated using Quaternary Phase Shift Keying (QPSK) modulation. In the proposed high data rate system, in addition to QPSK modulation, the signal is also modulated using 8-phase shift chain control (8PSK) and 16 quadrature amplitude modulation (16QAM). In order to balance the load on the in-phase (I) and quadrature-phase (Q) components of the QPSK signal, a complex PN spreading method is used. The plural PN extension technology is described in US Patent No. 08/856,428. The name of this application is "Reduced Peak-Average Transmitting Power High Data Rate in CDMA Wireless Communication System". This application was published on May 14, 1997 Japan filed an application and granted the assignee of the present invention, and it is expressly incorporated herein by reference.

The data to be sent is generated in the form of in-band (I) and quadrature (Q) samples, and the samples are provided by the input of a complex pseudo-noise (PN) expander 502. The complex PN spreader 502 mixes the I and Q samples with the short PN samples generated by the short PN code generator 504. The resulting PN extended sample stream is filtered by a baseband finite pulse response (FIR) filter 506 to generate a baseband complex sample stream, which is then up-converted and transmitted to a user station (not shown in the figure).

According to US Patent Application No. 08/856,428, the signal provided to the baseband FIR506 is extended according to the following equation: X _I =I*PN _I -Q*PN _Q (1)X _Q =Q*PN _I -I*PN _Q (2)

Where I is the digital in-phase sample, Q is the digital quadrature-phase sample, PN _I Is the in-phase short PN sequence, PN _Q Is the quadrature phase short PN sequence, and X _I And X _Q They are the signals sent to the in-phase and quadrature-phase channels after modulation. The signal represented by equation (1) is filtered by FIR filter 506A, and the signal represented by equation (2) is filtered by filter 506B. The FIR filter 506 is used for shaping the transmit waveform to accommodate it in the allocated bandwidth and minimize the interference between symbols.

The signal output by the FIR filter 506 is provided to the antenna transmitting subsystem 524, and each antenna transmitting subsystem 524 includes a separate transmitting antenna 522. The slot TDM timing generator 507 generates timing signals corresponding to various time division multiplexing (TDM) transmission cycles in each transmission slot. The slot TDM timing generator 507 provides an output signal to the beamforming control processor 508, which uses the output signal to alternately transmit signals corresponding to the even and odd TDM periods on the even and odd sub-sector signal beams.

Those familiar with the industry can understand that the beamforming control processor 508 can include a digital signal processor (DSP), a dedicated integrated circuit (ASIC), discrete gate logic, firmware, field programmable gate array (FpGA), and programmable Planning logic device (PLD), or any traditional programmable programming software module and microprocessor. This software module can be placed in the processor, RAM memory, flash memory, register, or any other form of storage medium known in the art. Another option is to use any traditional processors, controllers, state machines, and other devices that can generate and adjust the required amplitude and phase control signals to replace the microprocessor. Those skilled in the industry will understand that this configuration does not preclude the application of the function of the beamforming control processor 508 inside another processor already prepared in the transmitter device.

Based on the signal from the slot TDM timing generator 507, the beamforming control processor 508 provides individual phase and amplitude control signals to each antenna transmitting subsystem 524. By adjusting the phase and amplitude control signal coefficients and combining them with the antenna transmitting subsystem 524, the beamforming control processor 508 generates sub-sector beams and converts the sub-sector beams of the base station to on and off according to the even and odd time slots . A fixed set of phase and amplitude coefficients forms a sub-sector beam. During the operation time slot, the beam coefficient is used to form the focused sub-sector beam signal. During the time slot of no operation, the signal coefficient is set to zero to turn off the sector beam. As shown, the beamforming processor 508 provides the amplitude control signal α ₁ And phase control signal Φ ₁ To the antenna transmitting subsystem 524A, and provide the amplitude control signal α _n And phase control signal Φ _n To the antenna transmitting subsystem 524n.

In a specific example, the beamforming control processor 508 maintains a database of beamforming parameters most suitable for each sub-sector beam in the coverage area of the base station. Each antenna transmitting subsystem 524 includes components required for frequency up conversion, phase control, amplification, and signal transmission via a transmitting antenna 522. The signal provided by the baseband FIR506A is mixed in the mixer 512A with the mixed signal provided by the phase-controlled oscillator 510A. The signal provided by the baseband FIR506B is mixed in the mixer 514A with the mixed signal provided by the phase-controlled oscillator 518A. As shown, the phase control oscillators 510 and 518 receive the amplitude and phase control signals from the beamforming control processor 508, which are used to change the phase and amplitude of the output mixing signal such as waves. The output signals of the mixers 512A and 514A are added together in the adder 516A and provided to the amplifier 520A for transmission via the transmitting antenna 522A. Those skilled in the industry will understand that the transmitter subsystem 524N and other transmitter subsystems (not shown in the figure) have the same functions as the transmitter subsystem 524A.

What is not shown for each antenna transmitting subsystem 524 is a digital analog converter (DAC) that is required to convert the digital signal into an analog format before amplification and transmission. Those who are familiar with the industry will know that there are many places where the analog format can be used for conversion without departing from the scope of the present invention.

In a specific example, each antenna transmitting subsystem 524 includes a DAC placed between the adder 516 and the amplifier 520. In this specific example, the mixers 512 and 514 are digital mixers, and the phase control oscillators 510 and 518 generate digital oscillator signals. Each DAC is used to convert the digital output of the adder 516 into an analog signal, which is amplified and transmitted by the amplifier 520.

In an alternative embodiment, the input signal provided to the antenna transmitting subsystem 524 is already in an analog format (it has been converted to an analog format before being provided to the antenna transmitting subsystem 524). In this alternative specific example, the phase control oscillators 510 and 518 generate analog mixing signals, the mixers 512 and 514 are analog mixers, and the adder 516 is an analog adder.

Those who are familiar with the industry can also understand that the control of the signal transmitted by each antenna can be implemented in different ways. In an exemplary embodiment, the beamforming control processor 508 provides the amplitude control signal to each individual amplifier 520 of each antenna transmitting subsystem 524.

Those skilled in the art will recognize that the phase control oscillators 510 and 518 can be implemented in various ways. In an exemplary embodiment, a phase-controlled direct digital synthesizer (DDS) can be used to generate a digital sinusoidal signal with very fine phase resolution. In another specific example, the oscillators 510 and 518 are not phase controlled, but a phase shifter is placed between the adder 516 and the amplifier 520.

Although two antenna transmitting subsystems 524A, 524N are shown in FIG. 5, one or more antenna transmitting subsystems can be used in a beamforming base station. According to a typical configuration, a base station serves a sector divided into 4 sub-sectors. In this case, the 4-antenna transmitting subsystem 524 can be used.

Fig. 6 is a block diagram of an exemplary reverse link structure configured according to a specific example of the present invention. The data is divided into data packets and provided to the encoder 6l2. For each data packet, the encoder 612 generates a cyclic redundancy check (CRC) matching bit, inserts the code tail bit, and encodes the data. In a specific example, the encoder 612 encodes the data packet according to the encoding format disclosed in the aforementioned US Patent Application No. 08/743,688. Other encoding formats can also be used. The encoded data packet from the encoder 612 is provided to the interleaver 614 which sorts the code symbols in the data packet. The interleaved data packets are provided to a multiplier 616, which covers the data with Walsh and provides the covered data to the gain element 618. The gain element 6t8 is calibrated for data to maintain a constant energy value E for each bit _b , Regardless of the data rate. The scaled data from the gain element 618 is provided to the multipliers 650b and 650d, which expand the data with PN_Q and PN_I sequences, respectively. The expanded data from the multipliers 650a and 650d are supplied to filters 652a and 652d to filter the data, respectively. The filtered signals from filters 652a and 652b are provided to adder 654a and the filtered signals from filters 652c and 652d are provided to adder 654b. The adder 654 adds the signal from the data channel and the signal from the lead/DRC channel. The outputs of the adders 654a and 654b include IOUT and QOUT, respectively. These two outputs use in-phase sine waves COS(w,t) and quadrature sine waves SIN(w _c t) Modulation (as in the forward link), and addition before transmission. In this exemplary embodiment, the data communication is transmitted with sine wave in-phase and quadrature-phase.

In the exemplary embodiment, the capital is extended with a long PN code and a short PN code. The long PN code scrambles the data so that the receiving base station can identify the transmitting user station. The short PN code spreads the signal across the entire system bandwidth in the system. The long PN sequence is generated by the long code generator 642 and provided to the multiplier 646. Short PN _I And PN _Q The sequence is generated by the short code generator 644 and also provided to 646a and 646b, respectively. These multipliers multiply the two sequences to form PN_Q and PN_I signals, respectively. The timing/control circuit 640 provides a timing reference for the PN code generators 642 and 644. The generation and use of the PN sequence is known in the art and is described in US Patent No. 5,103,459.

An exemplary block diagram of the data channel structure is shown in FIG. 6. This structure is one of many structures that support data encoding and modulation on the reverse link. For high-rate data transmission, one of the structures using multiple orthogonal channels similar to the forward link can also be used. Other structures that fall within the scope of the present invention can also be considered, such as the structure of a reverse link communication channel that conforms to the IS-95 standard in a CDMA system.

In the exemplary embodiment, the reverse link data channel supports 4 data rates listed in Table 1. It can also support additional data channels and/or different data rates. In the exemplary embodiment, the data packet size for the reverse link is determined by the data rate as shown in Table 1. As described in US Patent Application No. 08/743,688, improved decoder performance can be obtained for larger packet sizes. Therefore, data packet sizes different from those listed in Table 1 can be used to improve performance. In addition, the data packet size can be made as a parameter that is not related to the data rate.

<tables><img file="TW511382B_D0001.tif" /></tables>

As shown in Table 1, the reverse link supports multiple data rates. In the exemplary embodiment, after registering at a base station, each user station is allocated a minimum data rate of 9.6 kbps. In an exemplary embodiment, the user station can transmit data on the lowest rate data channel at any time slot without requesting permission from the base station. In the exemplary embodiment, the selected base station is based on, for example, the system load. Fairness and total transmission quality are a set of system parameters that allow data to be transmitted at a higher data rate. An exemplary scheduling mechanism for high-speed data transmission. It is described in detail in U.S. Patent Application No. 08/798,951, and its name is "Method and Apparatus for Forward Link Rate Scheduling". This application was filed in 1997 Filed on February 11, 1997, and US Patent Application No. 08/914,928, named "Reverse Link Rate Scheduling Method and Device". This application was filed on August 20, 1997. The second application The cases are all assigned to the assignee of the present invention and incorporated herein by reference.

An exemplary block diagram of the lead/DRC channel is shown in FIG. 6. The DRC message is provided to the DRC encoder 626 which encodes the message according to a predetermined encoding format. The DRC message encoding has its importance. This is because the error probability of the DRC message needs to be low enough, because the incorrect determination of the data rate of the forward link will affect the system throughput performance. In the exemplary embodiment, the DRC encoder 626 is a rate (8,4) block encoder that encodes the DRC message into a codeword. The encoded DRC message is provided to a multiplier 628, which uses a Walsh code to cover the message, and the Walsh code can uniquely identify the destination base station to which the DRC message points. The Walsh code is provided by the Walsh generator 624. The covered DRC message is provided to the multiplexer (MUX) 630, which multiplexes the message together with the leading data. The DRC message and the pilot data are provided to the multipliers 650a and 650c, and these multipliers use PN_I and PN_Q signals to expand the data. Therefore, this citation and DRC message are transmitted with both in-phase and quadrature-phase sine waves.

In the exemplary embodiment, the DRC message is sent to the selected base station. This can be accomplished by overwriting the DRC message with a Walsh code that can identify the selected base station. In the exemplary embodiment, the length of the Walsh code is 128 chips. The derivation of this 128 chips is known in the art. A unique Walsh code is assigned to each base station that communicates with the user station. Each base station uncovers the signal on the DRC channel with its designated Walsh code. The selected base station can uncover the DRC message and send data to the user station via the forward link in response to the request of the user station. Other base stations can determine that the requested data rate is not for their transmission, because these base stations have been assigned different Walsh codes.

In an exemplary embodiment, the reverse link short PN codes used by all base stations in the data communication system are the same, and there is no offset used to distinguish different base stations in the short PN sequence. The data communication system supports soft handover on the reverse link in an advantageous manner. Using the same short PN code without offset allows multiple base stations to receive the same reverse link transmission from the user station during soft handover. Therefore, the short PN code provides spectral spread, but it can be advantageous to not consider identifying the base station.

In an exemplary embodiment, the DRC message carries the data rate requested by the user. In an alternative specific example, the DRC message carries a forward link quality message (for example, C/I information measured by the user station). During the message acquisition period, the user station can simultaneously receive forward link pilot signals from one or more sub-sector beams and perform C/I measurements on each received pilot signal. During the message acquisition period, the user station searches for and measures the pilot signal on the even and odd time slots. The user station selects the beam with the highest C/I value. The subscriber station is then in the opposite reverse link slot period. You can send a DRC message to the link time slot before receiving data. If the user station steps into a new sub-sector, it will switch from even to odd time slots (or vice versa). After obtaining the information, as described in US Patent No. 5,504,773, the C/I value is estimated by the user station, but when the data is received, the C/I value is only measured in alternate even or odd slots. The user station then selects the best sub-sector beam based on a set of parameters including current and past C/I measurements. The data rate control information is made into a formatted DRC message, which can be sent to the base station of one of several specific examples.

In the first specific example, the DRC message is transmitted according to the requested data rate. The requested data rate is the highest supported data rate, which can produce satisfactory performance at the C/I value measured by the user station. The user station uses the C/I measurement value to first calculate the maximum data rate that can produce satisfactory performance. Then quantify this maximum data rate into a supportable data rate and designate it as the requested data rate. The data rate indicator corresponding to the requested data rate is sent to the selected base station. An exemplary supportable data rate group and corresponding data rate indicators are shown in Table 1.

In another specific example, the user station transmits a forward link quality index to the selected base station, and the user station sends a C/I index representing a quantified C/I measurement value. This C/I measurement value can be mapped to a table and correlated with a C/I index. Using more bits to represent the C/I index can obtain a more precise quantification of the C/I measurement value. In addition, the mapping can be linear or pre-distorted. For a linear mapping, each increment of the C/I index represents a corresponding increase of one of the C/I measurement values. For example, each step of the C/I index can represent a 2.0 dB increase in the C/I measurement value. For pre-distortion, each increment of the C/I index can represent a different increase in the C/I measurement value. For example, a pre-distorted map can be used to quantify the C/I measurement value to match the cumulative distribution function (CDR) of the C/I distribution. In other specific examples, it can also be considered to transmit the rate control information from the user station to the base station, and it also falls within the scope of the present invention. In addition, the use of different numbers of bits to represent data rate control information also falls within the scope of the present invention.

In an exemplary embodiment, the C/I measurement can be performed on the forward link pilot signal similar to the method used in the CDMA system. A method and device for C/I measurement was disclosed in US Patent Application No. 08/722,763, and its name is "Method and Device for Measuring Link Quality in Spread Spectrum Communication System", which was published in September 1996 An application was filed on the 27th and the assignee of the present invention has been granted, and is expressly incorporated herein by reference. The C/I measurement of the pilot signal can be obtained by despreading the received signal using a short PN code.

In the former alternative specific example, C/I measurement can be performed on the forward link communication channel. The communication channel signal is first despread with long PN code and short PN code and decovered with Walsh code. The C/I measurement of the signal of the data channel can be more accurate, because a larger percentage of the transmit power is allocated for data transmission. Other methods for measuring the C/I value of the received forward link signal by the user station are also considered and fall within the scope of the present invention.

In an exemplary embodiment, the DRC message is transmitted in the first half of the time slot. For an exemplary 1.667 millisecond time slot, the DRC message includes the first 1024 chips or 0.83 millisecond time slot. The remaining 1024 chip time is used by the base station to demodulate and decode DRC messages. The transmission of the DRC message in the previous part of the time slot enables the base station to decode the DRC message in the same time slot and possibly transmit data with the data requested in the subsequent time slot. The processing delay enables the communication system to quickly adapt to changes in the operating environment.

In an alternative specific example, the requested data rate is transmitted to the base station by using an absolute parameter and a relative reference. In this specific example, the absolute reference frame including the requested data rate is transmitted periodically. Absolute reference enables the base station to determine the actual data rate requested by the user station. For each time slot between transmissions of the absolute reference, the user station transmits a relative reference to the base station to indicate whether the requested data rate for the upcoming time slot is higher than that of the previous time slot High, low, or the same. The user station transmits the absolute reference periodically. The transmission of the periodic data rate indicator enables the requested data rate to be set in a known state and ensures that incorrect reception of relative parameters does not accumulate. The use of absolute and relative parameters can reduce the transmit rate of DRC messages to the base station. Agreements on other data rates required for transmission are also considered and fall within the scope of the present invention.

When users have requirements for the service quality of the communication system, they further hope to understand the corresponding C/I limiting factors for a specific bit rate and bit error rate, such bit rate and bit error rate It will cause restrictions on the transmit power of each user in the system. It should be noted that the data signal sent to one user is noise or interference to another user. Therefore, it is hoped that not only the use of all time slots can be optimized, but also the C/I of each individual user can be increased. When all sectors receive signals transmitted at full power, the C/I of sector "i" is defined by the following formula:

<maths><img file="TW511382B_D0002.tif" /></maths>

Where ij. Divided into is the transmit power sent to sector i, and the denominator is the sum of the transmit power sent to other sectors and/or cells. Generally speaking, for users with transmit power level P to "Z" _Full For one system, the above relationship can be simplified as:

<maths><img file="TW511382B_D0003.tif" /></maths>

The formula shows the wavelength of the effective power. Increasing the number of users in the system will reduce the C/I value, which will reduce the service quality for individual users and possibly all users. Therefore, it is desirable to reduce the denominator value by transmitting at a reduced power level to at least some (Z-1) users. For example, in an exemplary embodiment, the base station of a cell transmits to each sector according to the time division power level allocation. The C/I of the sector i used in the exemplary embodiment is calculated as follows:

<maths><img file="TW511382B_D0004.tif" /></maths>

In the formula, the base station transmits to the sector "j" to use full power, P _Full And transmit to the sector "k" to use reduced power, P _Reduced . All mobile units in a sector receive the signal transmitted at the corresponding power level. An effective way is to include any number of power levels in this relationship. The introduction of a lower power term can lead to an increase in the corresponding C/I for mobile units in sector i in an advantageous way, and thus improve the quality of service for these mobile units, while enabling mobile units in other sectors Continue to receive information. The reduction of power in other sectors can reduce the interference suffered by sector i. In an exemplary embodiment, the transmitted signal is divided into a predetermined number of repetitive time slots. Each sector receives a full-power transmission signal with at least one time slot in each cycle. In alternative specific examples, the signal power can be adjusted according to capacity and usage. For example, when there is no communication activity in a sector, no high-power signal is sent to that sector, but there are slots for high-power time slots allocated to other sectors with communication services. In this kind of system, the time division power allocation is adaptive according to the current communication.

According to an exemplary embodiment, a single frequency is used in multiple adjacent sectors. The transmitted signal is generated corresponding to a fixed number of time slots in each cycle, where the number of time slots is equal to the number of sectors. In a set time slot, each sector is allocated a power level, where the power allocation indicates the power level transmitted to the sector. In an exemplary embodiment, the number of power levels is equal to the number of time slots in each cycle. During the next time slot, the power distribution changes. Since only one sector receives high-power signals, time-division power allocation is used to reduce the interference of transmitted signals. In an alternative specific example, several sectors that are not equal to the number of sectors can be used, where the number of time slots can reduce interference to at least one transmitted signal. For example, the number of time slots can be equal to the number of sub-sectors in a sector. An alternative method is that the number of time slots can be greater than the number of sectors and/or sub-sectors in order to perform power control on multiple time slots, for example, when the allocation pattern results in a predetermined average power value, or other power control is used to reduce the number of sectors. The algorithm of interference between regions and/or sub-sectors.

FIG. 7 illustrates an exemplary embodiment in which a single cell has 3 sectors labeled "A", "B" and "C". A single base station (not shown) transmits individual signals into each sector A, B, and C. Each of the 3 launches from the base station is controlled according to the time slots marked "1", "2" and "3". The time slot 1, 2, 3 repeats in sequence in a loop. Since the base station transmission is provided according to the time slot design, the timings in all 3 sectors are synchronized. Therefore, the time slot 1 in the sector A is consistent with the time slot 1 in the sectors B and C.

In Figure 7, the full power is P _F Represents, the lower power level is P _R1 And P _R2 Representing. By transmitting to a sector at a high power level and transmitting to an adjacent sector at a low power level, the interference in the high power sector is reduced. In an alternative embodiment, a reduced power level can be used to transmit to multiple sectors.

According to an exemplary embodiment, each sector receives a transmission signal during each time slot. In alternative specific examples, it may include unoccupied time slots, and/or may include fewer power levels, where a single power level is allocated to multiple sectors. In the exemplary embodiment, the base station determines the time division of the transmitted signal. All signals from the base station are generated according to this timing. The base station adjusts the power of each transmitted signal according to the cycle design consistent with this timing. For example, as shown in Figure 7, during the first time slot 1, sector A is allocated a high power level, which is a full power or an adjusted power level, and sector B is allocated a low power level and Sector C is a mid-range power level. The power level allocation is valid for the entire time slot. In the next sequence of time slot 2, the power allocation changes, sector A is allocated a mid-range power level, sector B is allocated a high power level, and sector C is allocated a low power level. The power allocation of the sector is cycled through the power level. However, it should be noted that in this exemplary embodiment, the order of the power allocation of the set sectors does not change. For example, the power allocation order of sector A is: high, medium and low. The power allocation of sector B is low and high. The power allocation of sector C is medium low and high. During a set time slot period, only one sector has high power level allocation. In this case, the interference to the sector can be reduced and the C/I of the set time slot can be increased. This exemplary embodiment can reduce inter-symbol interference (ISI) in an advantageous manner by allocating a high C/I time slot for each sector.

According to an exemplary embodiment, during each time slot, each sector is assigned a unique power level maintained in sequence. In an alternative specific example, such power allocation and the order of power allocation are adjusted according to the communication system. In an alternative specific example, the order of power allocation for a sector can be changed, in which at least one sector receives a high-power level transmission signal. For example, the power level allocation for one sector can be adjusted relative to other sectors according to their interference situation. This enables the base station to perform according to a dynamic function. Rate allocation design launch.

Each mobile unit in the sector provides DRC information to the transmitter during each time slot. For example, when a system has a time division of 3 time slots per cycle, together with 3 time slots per cycle, and 3 power levels, each mobile unit provides at least 3DRC to the base station, and each power level also has a CRC in the real time slot. . The DRC information is based on the estimated C/I value of a set time slot and a time slot with a related power level. A digital filtering process is explained in the following, and the C/I estimated value is repeatedly provided according to an adaptive method, wherein the calculation process includes the feedback from the previous cycle. During a set time slot period, digital filtering is implemented in a sequence of repetitions to filter the symbols emitted during the time slot period. A digital filter operation includes a predetermined number of symbolic sample groups. At each iteration, a C/I estimate is generated. Each C/I estimate includes calculations from previous time slots at the same power level. Also real-time slot 1 calculations include historical information obtained from previous slot 1 calculations. It should be noted that the power allocation order may not be maintained in the alternative specific example, so the historical information corresponding to each power level can be represented by different time slots. In an exemplary embodiment, for sector A, the estimated C/I value of time slot 1 is averaged with at least one previous time slot 1 calculation value. Any number of time slots can be used to determine an estimate, where increasing the number of historical information may increase the accuracy of the estimate. The amount of historical information included in each C/I iteration can be limited by the power level and/or time slot, and the ability of the system to store previous information. Previous C/I results can be stored in a buffer or another memory storage device. Similarly, the C/I estimation information can be stored in the form of a matrix, where the composed vector corresponds to a specific power level allocated to a specific sector. In an exemplary embodiment, the matrix may include C/I information for 3 sectors and 3 power levels for each sector, or at least 9 vectors.

A mobile unit transmits DRC information corresponding to each allocated power level back to the base station. Therefore, during each active time slot, the mobile unit sends DRC information according to the average estimated value of C/I. The base station determines the data rate for transmitting data to the mobile unit for a set time slot based on the DRC value. Although there are equal numbers of power levels and slots in the exemplary embodiment, this is not necessarily the case. This can clarify the above discussion and understand that DRC is related to a specific power level. As discussed above, DRC can be provided as a list of values, and the base station can transmit within this list of values, or as a specific rate. Similarly, the mobile unit can directly provide C/I estimates and enable the base station to determine the appropriate DRC.

In a specific example, the mobile station calculates the C/I, performs the average calculation, and selects the DRC from the checklist. In an alternative specific example, the mobile station sends the C/I estimate to the base station, and the base station determines the appropriate data rate. At each iteration, the C/I estimate is calculated by balancing or filtering the received signal. The purpose of balance is to reduce any ISI introduced by the transmitting channel. The balancing operation can therefore correct the distortion introduced by the channel.

FIG. 8 illustrates a receiver circuit 700 operating in one of the sectors of a cell in a wireless communication system. The receiver 700 estimates the C/I and provides a corresponding DRC message and sends it back to a base station (not shown). The receiver 700 includes an antenna 702, an RF/IF processor 704, a bandwidth filter 706, and a sampler 708 coupled to an equalizer 710. In the exemplary embodiment, the balancer 710 is a finite impulse response (FIR) filter for averaging a discrete sequence of input values. An exemplary balancer is described in a U.S. patent application named "Method and Apparatus for Processing Modulated Signals Using an Equalizer and Rake Receiver", which was filed on July 24, 2000 The assignee of the application and the granting of the present invention is hereby expressly incorporated herein by reference.

Referring now to FIG. 8 again, the balancer 710 is exemplified as an FIR filter, which can be implemented using a finite impulse response (FIR) filter or other filter structures. The balancer 710 outputs the average value of a sample group of the input symbols received by the sequence. This sample group is taken from a set number of consecutive symbols. Similarly, the number of symbols in this group is set to (2L+1). The balancer 710 includes a series of delay elements 712 to 716. There are tap points between the delay elements to provide individual sample values to the multipliers 718 to 724. The output of the tap is amplified and added in the adder 728. Each multiplier 718-724 receives filter coefficient values for scaling or amplifying individual sample values. The number of tap points is equal to the number of symbols in each sample group, that is, (2L+1). The FIR structure implements the convolution of filter coefficient values and sample groups in an effective manner.

The number of delay elements is one less than the number of taps, because there is a tap for the most recently received symbol before the delay. Each delay element provides a delay equal to the symbol duration. This delay is set to T/M, where T is the symbol period, and M is the classification component of the sample. In general, M=1 and sampling is performed once during each symbol duration T. In an alternative specific example, M=2 can be set, where 2 samples are taken from each symbol duration T. In the exemplary embodiment, there are 3 time slots corresponding to the number of sectors.

As shown in Figure 7, each time slot is further divided into fewer time intervals called symbols. There are N symbols in a time slot, and each symbol has a duration T. The balancer operates the N-symbol sub-combination of a sub-set in a time slot. Please note that the time slot can be called a box. In a time slot "i", the balancer 710 receives consecutive samples, the samples are set to Xi(n), and n=1,2,...(2L+1), where "n" is the same as used in a time slot The integer sequence of the time indicator of this combination. In an exemplary embodiment, the sample combination is increased by one symbol at a time through the delay elements 712 to 716 of the balancer 710.

The output of each of the delay elements 712 to 716 is determined by a corresponding tap coefficient C _i,(-L) ,C _i,(-L+1) ,...C _i,(L) . The first coefficient index indicates the time slot of the transmitted signal, that is, the power level. The second coefficient index indicates the position of the tap point in the delay elements 712 to 716, and is set by the sequence {-L, (-L+1),...,0,...,(L-1),L}. The amplified result adds up and thus provides an estimate of one of the discrete received symbol sequences Xi(n) <img file="TW511382B_D0005.tif" /> i(n).

The balancer 710 is an adaptive balancer, the coefficients of which are continuously adjusted by the transmitted data. The coefficient n used for repetition is a function of the repetition value (n-1), namely c _i (n)=f(c _i (n-1)). In an alternative specific example, a preset balance method can be implemented to adjust the coefficient. The disadvantage of this preset method is that the training session needs to be started, and the performance degradation of the channel over time may be invalid. An alternative is to use preset activation followed by adaptive repetition for balancing purposes.

In the adaptive balancer 710, the C/I estimation obtained from each iteration provides feedback for adjusting the tapping point coefficient for the next iteration, and provides information to determine an appropriate data rate for the receiver and Its related DRC use. For a given repetition, the balancer 710 forms an estimated value as shown in the following equation:

<maths><img file="TW511382B_D0006.tif" /></maths>

in <img file="TW511382B_D0007.tif" /> As a coefficient index, the estimated value is evaluated for all tap points. In alternative specific examples, a part of the taps can be used, or the number of taps can be dynamically changed to evaluate the estimated value.

In the exemplary embodiment, a set of coefficients is generated corresponding to each time slot. When calculating for each time slot, the above estimated value y _i (n) is to record every time slot i is generated. Its general formula is as follows:

<maths><img file="TW511382B_D0008.tif" /></maths>

The index i represents the time slot. In the exemplary embodiment, there are 3 time slots, that is, i={1,2,3}. Alternative specific examples can be set to use any number of time slots for the system and configuration as needed.

Output estimate <img file="TW511382B_D0009.tif" /> i(n) is provided to other modules in the receiver 700 and also provided to the coefficient adjustment unit 730. The coefficient adjustment unit 730 determines the current time slot and adjusts the corresponding coefficient group. The coefficients are stored in a memory storage device (not shown) and retrieved during each time slot as needed. For example, during the first time slot, the calculation for sector A reflects the full power signal broadcast during that time slot. When the power drops, the C/I value is expected to be greater than the second or third time slot period for sector A. The coefficient adjustment unit 730 may include a check table that associates the C/I estimated value with the related DRC. It should be pointed out that the mobile unit sends a DRC for each time slot based on the C/I averaged in the corresponding time slot.

Regarding the balance processing of each time slot is continuous, during the previous corresponding time slot (that is, the power level), the self-processing is terminated. Now consider an example in which a time slot is composed of N symbols and the balanced sample group includes (2L+1) symbols. The repetition index n used for the first occurrence of slot 1 is set to n={1,2,3,...(N-2L)}. When the time slot 1 is terminated, the coefficient value is stored for the next time slot 1 occurrence. Please note that one algorithm can be used to store information in another form, such as a check and other results that can provide the necessary coefficient and/or C/I estimate information. When the second time slot 1 occurs, the stored value is used to start the repetition of the balancer 710. Each time slot is processed in the same way, so the stored information can be retrieved during the next corresponding time slot. In alternative embodiments, more than one power level may be used to generate C/I estimates for a sector.

A base station uses time-division power allocation for beam switching to transmit to sectoral partitions. It can reduce the power sent to all sectors except one sector and therefore increase the C/I of that sector, thereby reducing the impact on neighboring sectors. Interference of user stations in the sector.

According to a specific example, the balancer 710 is used as a finite transversal filter for channel self-passing and balancing. Coefficient adjustment The coefficient is modified to minimize the signal separation and ISI at the output. The output is generally provided to a limiter or decision mechanism, so the balancing step is directly related to the quality of the data. Coefficient adjustment involves comparing the estimated C/I with a real value. In the exemplary embodiment, the least mean square (LMS) or least mean square error (MSE) algorithm is used. However, in alternative specific examples, any algorithm that generates estimates based on historical information can be used. Such algorithms include, for example, Mean Square Error Gradient (MSEG), Recursive Least Squares (RLS) and Direct Matrix Inversion (DMI). In general, the estimated value yi(n) is an output sent to a limiter (not shown) that makes a decision on the symbol value. An error term is calculated by comparing the balanced value (that is, the output of the summing node 728) with the limited value. The result is the estimated error.

Using the LMS algorithm, a vector of filter coefficients for each sector i is defined as follows:

<maths><img file="TW511382B_D0010.tif" /></maths>

The adjusted coefficient values are set as follows:

<maths><img file="TW511382B_D0011.tif" /></maths>

In this equation, each coefficient is adjusted according to the estimated error. During the transmission period with reduced power, the base station may not transmit certain signals, or transmit additional signals with reduced power. These additional signals include, but are not limited to, pilot signals, and reverse power control (RPC) signals. If the power control is invalid during the time slot period when the power is reduced, the power control frequency is reduced by a coefficient "S" equal to the number of time slots, where i={1,2,...,S}. The reduced power control frequency results in coarse power control of the mobile unit. The control signal is not sent out frequently, so the corresponding control adjustments are not often implemented. In other words, the adjustment of the mobile unit's power is not as fast as the control of higher frequencies. Coarse control not only introduces excessive power (ie interference) into the communication system, but also causes the mobile unit to consume more power, which affects the battery life between recharges. Especially in CDMA systems, it is desirable to provide power control frequently during each time slot for fine power control adjustment. In an exemplary embodiment, multiple power signals are transmitted during each time slot, wherein even during the reduced power time slot, the RPC signal is still transmitted at full power. The pilot signal can be transmitted at this time slot at a reduced power level. The estimated value of the impulse C/I of the mobile unit during the power-down slot period, and considers the received reduced pilot strength. The base station provides the power allocation of each mobile station in relation to each time slot. In this case, the mobile station anticipates the reduced power and responds accordingly. It can be noted that when the mobile station receives signals from multiple base stations, the mobile station considers the power allocation of each base station.

Although the exemplary embodiment transmits a signal during all time slots, the alternative embodiment may use a part of the time slot. In this part, at least one time slot is not available except for sectors that can receive full signal power. Health effect. Similarly, the power allocation can be adaptive, where the base station can change the power allocation based on the feedback from the mobile unit, and this feedback includes but not limited to DRC information and requests for retransmission of data to correct errors. The base station can change the reduced power level to match the mobile unit in the system. For example, if mobile users experience excessive data errors, the reduced power level can be increased. Similarly, the power level can be adjusted according to a list of values for optimal operation, in which the adjustment of this range will result in the elimination of the power level, that is, the level is replaced by a non-functioning situation. In a specific example, the signal power provided is from 3dB to 6dB. In alternative embodiments, any power level can be used, where a high power level is used for one sector and at least a reduced level is used for another sector.

The specific examples disclosed herein provide a method of using sub-sector beam support technology to reduce the average interference caused by a base station transmitting to a user station in a cell and adjacent cells.

Therefore, a novel and improved method and device for improving the previous transmission of data to the link has been described so far. Those who are familiar with the technology of the industry should understand the data, instructions, commands, information, signals, bits, symbols, and chips cited in the above-mentioned entire description, which can all be used in an advantageous manner from the voltage, current, electromagnetic wave, and magnetic field in the description. Or particles, light fields or particles, or any combination of them. Those who are familiar with the industrys technology can further understand that the various logic blocks, modules, circuits, and algorithm steps described in the specific examples disclosed in this article can be regarded as electronic hardware, computer software, or two A combination of those to be used. Such different illustrative components, blocks, modules, circuits, and steps have been briefly described in terms of their functions.

Whether these functions are used as hardware or software is determined by special applications and restrictions imposed on the overall system design. Skilled technicians will recognize the interchangeable nature of hardware and software in this environment, and how to best use the described functionality for each particular application. For example, together with the various illustrative logic blocks, modules, circuits, and algorithm steps described in the specific examples disclosed herein, a digital signal processor (DSP) can be used. A dedicated integrated circuit (ASIC), a field programmable array (FPGA) or other programmable logic devices, discrete gates or transistor logic, such as separate hardware components for registers and FIFOs, perform one A processor with a set of firmware commands, any traditional programmable software module and a processor, or any combination designed to implement the functions described in this article. The advantageous type of processor is a microprocessor, but the processor can also be selected as any conventional processor, controller, microcontroller or state machine. The software module can be installed in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, scratchpad, hard disk, replaceable disk, CD-ROM, or any technology in the bank Know the other forms of media. The processor may be housed in an ASIC (not shown). The ASIC may be placed in the phone (not shown). In an alternative specific example, the processor may be placed in the phone. The processor can be used as a combination of a DSP and a microprocessor, or as two microprocessors connected with a DSP core, and so on.

The above description of the preferred specific examples can enable any person skilled in the art to manufacture or use the present invention. The various modifications to these specific examples are obvious to those familiar with the industry, and the generic principles defined in this article can be applied to other specific examples without using innovative technologies. Therefore, the present invention is not intended to be limited to the specific examples shown in this article, but should be allowed to have the widest scope that conforms to the principles and novel features disclosed in this article.