Apparatus and method for controlling a signal

This application claims the benefit of 35 U.SC § 119 of provisional application 60 / 734,208 filed in the United States on November 7, 2005.

This disclosure relates generally to communication systems, and in particular to wireless systems including terrestrial broadcasting, cellular, Wi-Fi (Wireless-Fidelity) and satellite communications.

This section aims to introduce the reader to various technical aspects. Various technical aspects may relate to various aspects of this disclosure as described and / or claimed below. We believe that this description will be useful in providing background information to the reader and facilitating a better understanding of the various aspects of this disclosure. Therefore, it can be seen that these statements should be read from this point of view, not as an approval of the prior art.

In the United States, TV spectra now have ATSC (Advanced Television Systems Committee) broadcast signals that coexist with NTSC (National Television Systems Committee) broadcast signals. ATSC broadcast signals are also called digital TV (DTV) signals. NTSC transmission is scheduled to end in 2009, at which point the TV spectrum has only ATSC broadcast signals. However, in some given region of the country, a significant amount of the TV spectrum is left unused to avoid interference between broadcast channels, as would be the case if only NTSC broadcast signals were present.

Recently, government agencies and businesses have suggested that in the future different services may share frequency bands such as the broadcast TV spectrum. Various standards bodies are proposing a new wireless service known as WRAN (wireless regional area network) that shares the TV spectrum currently used by terrestrial television broadcasting. One such proposed WRAN system aims to utilize unused broadcast channels in the TV spectrum on the basis of non-interference. The main purpose of the proposed WRAN system is to address broadband access in rural and remote areas as well as in low population density unserviced markets, with performance similar to broadband access technology serving urban and suburban areas. To provide a level. In addition, the proposed WRAN system can also be estimated to serve densely populated areas where the spectrum is available.

<p> Interference between the two systems must be reduced in order for the WRAN system and the currently existing broadcast signals to share the spectrum. One way to control interference is to ensure that, in some cases, the two services have orthogonal polarization of each signal emission pattern. In the United States, broadcast TV signals are generally transmitted using horizontally polarized waves. WRAN systems attempting to operate in or around broadcast channels used by local broadcasters may need to transmit using vertically polarized waves to minimize interference.</p><p> Antennas used by WRAN devices may require precise placement in order for WRAN devices (such as base stations and in-house devices) to achieve transmission using specific (eg, vertical) radiation polarization patterns. .. One indicator of such an arrangement may be, for example, determining the amount of cross polarization separation between vertical or horizontal radiation patterns. For example, the amount of interference polarization separation given as 14 dB may be used as an indicator of the exact placement of the appropriate radiation polarization and may be acceptable to ensure minimal interference between services.</p><p> One possible way to achieve the high level of coherent polarization isolation required to ensure the desired radiated polarization of the antenna used in the WRAN equipment is to use a skilled or professional installer. To install the antenna used by the WRAN device. The antenna may have a reference member that can be adjusted with a level or plumb bob or some electrical measuring device to achieve a particular radiation pattern orientation. Antenna adjustments and adjustments are performed before allowing transmission by the WRAN device. Skilled or professional tuning ensures proper placement of the radiating elements and produces the desired coherent polarization, thus ensuring the desired radiating polarization.</p><p> However, it can be seen that the specialized installation of antennas used in WRAN equipment is unnecessarily expensive. In addition, the antenna adjustment after the initial adjustment may require the installer to return due to environmental or other conditions. Moreover, if the antenna is misaligned and does not radiate in the proper polarization direction, unnecessary and unwanted interference with the broadcast signal can occur. Therefore, it has an antenna system that can achieve a proper radiation pattern and only when properly placed to minimize interference with shared broadcast services, it transmits wireless services such as WRAN services. It is desirable to enable.</p>

<p> The disclosed embodiments relate to devices and methods of controlling the transmission of signals in communication devices. In one embodiment, a transmitter that transmits a signal, an antenna that is coupled to the transmitter and emits a signal in a radiated polarization pattern, and a controller that adjusts the transmitter when the radiated signal exhibits an undesired polarization pattern. Devices having and are described.</p><p> In the second embodiment, the steps of generating a signal for transmission, the step of radiating the signal with a polarization pattern, and the generation of the signal for transmission when the radiation signal shows an undesired polarization pattern are coordinated. A method having steps and is described.</p>

The features and advantages of this disclosure may be apparent from the following detailed description given as an example.

One or more specific embodiments of the present invention will be described below. Not all features of the actual implementation are described in the specification to provide a brief description of these examples. Numerous implementation-specific to achieve designer-specific objectives, such as compliance with system-related and business-related constraints, in some actual implementation deployment, such as some engineering or design plan. It turns out that the decision must be made. These can vary from implementation to implementation. Moreover, such deployment efforts can be complex and time consuming, but nevertheless prove to be the routine work of design, production and manufacturing of those skilled in the art who benefit from this disclosure.

The following describes the systems and circuits used to transmit and receive signals in WRAN. Other systems and circuits used to transmit and receive other types of signals in other networks may also have very similar structures. Those skilled in the art will recognize that the examples of circuits described herein are merely one potential embodiment. Thus, in alternative embodiments, system components may be rearranged or omitted, or additional components may be added based on specific attributes of the system. For example, with minor changes, the described circuit may be configured for use in other wireless networks such as IEEE 802.11.

With reference to the drawings and first with reference to FIG. 1, an exemplary WRAN block diagram 100 is shown. The network 110 (such as an internet network provided by an internet service provider) is physically interfaced with the base stations 120a and 120b shown in the building. Each base station 120a and 120b typically has a circuit that interfaces the network 110 with other devices used in WRAN. Each base station 120a and 120b may also have equipment located within the building and antennas located at the top of the building to provide wireless interfaces to other equipment used in WRAN. May have.

Each base station 120a and 120b, through a wireless interface, is one or more customer premises equipment (CPE) devices 130a-in various structures within the geographical perimeter of base stations 120a and 120b. Communicate with h. The structure containing the CPE device 130a-h may be in a fixed position such as a house or apartment building, or may be a moving body (not shown) such as a car. In a preferred embodiment, the geographical perimeter area between base stations 120a and 120b and CPE equipment 130a-h is separated into cells based on boundaries determined by radio signal characteristics and terrain. Further, one or more CPE devices 130a-h may be able to communicate with the base stations 120a and 120b and may also be able to communicate with other CEP devices 130a-h. For example, the CEP device 130h may be able to communicate with both the base station 120b and the CPE devices 130e, f and b, as shown. Thus, the CPE device 130h can be known as a repeater device in WRAN.

Referring to FIG. 2, a block diagram of an exemplary system 200 used in WRAN is shown. The illustrated block diagram is shown in a simple form with no interconnects. A plurality of blocks of an exemplary system 200 have circuits within the blocks not shown but further described below. As shown in FIG. 1, the WRAN system has at least one base station 210 capable of servicing a geographical area (WRAN area). The base station 210 may have a circuit that processes and converts information and contents received from the network through the network interface. Base station 210 may also have transceiver circuits that transmit and receive information using WRAN. The base station 210 communicates with the CEP 240 by WRAN through the antennas 220 and 230 attached to the base station 210 and the CPE 240, respectively. In one embodiment, the physical layer protocol for communication between base station 210 and CPE240 is based on orthogonal frequency division multiplexing (OFDM) using packet data structures.

The CPE 240 has one or more processors and associated memory, as represented by the processor 260 and memory 270. In this regard, the computer program or software is stored in memory 270 for execution by processor 260. Processor 260 may also control other functions of CPE240. The memory 270 represents some storage device (eg, random access memory (RAM), read-only memory (ROM), etc.) and may be internal or external to the CPE 240. The memory 270 may be volatile or non-volatile, if desired. The CPE 240 also has a transceiver 250 that uses the antenna 230 to receive and transmit information on the WRAN. The transceiver 250 may communicate the information received or transmitted by WRAN directly with the processor 260 or with a signal processor. The transceiver 250 is described in detail below. The CPE240 may further have a user interface component such as a keyboard and a display screen that interacts directly with the user. Further, the CPE 240 may provide an indirect interface such as USB (universal serial bus) that interfaces with an external device such as a home computer or television.

To enter the WRAN network, the CPE 240 may first "associate" with the base station 210. During this association, the CPE 240 uses the control channels configured in the communication protocol to transmit information, including the functionality of the CPE 240, to the base station 210 via the transceiver 250 and the antenna 230. The reported features include, for example, minimum and maximum transmit power and a list of supported channels for transmit and receive. The base station 210 may reply to the CPE 240 regarding the operating requirements of the data communication channel and the function of WRAN through the antenna 220, through the same control channel or through an alternative channel. Functions and requirements from base station 210 may also have additional information such as the polarization orientation required for antenna 230 or any local TV channel polarization orientation for proper operation on the data communication channel. Good. The CPE240 may further perform actions that determine the signal environment, such as determining which TV channel is present. Resulting information about the signal environment may be provided to base station 210 to modify or increase the list of supported channels used in WRAN communication.

As mentioned above, the WRAN system utilizes unused TV broadcast channels of the TV (television) spectrum and shares the spectrum based on secondary use. In this regard, the WRAN system follows the behavior of the local broadcaster to avoid interference with the behavior of the local broadcaster. As a result, the CPE240 may have the ability to determine the presence of a local broadcaster, for example by detecting signal energy. In addition, the CPE240 also has the ability to avoid interference with local broadcasters using the components and techniques described herein.

With reference to FIG. 3, a block diagram 300 of an embodiment of a transceiver using an embodiment of the present invention is shown. Transceiver circuits such as those found in CPE240 will be described below, but transceiver circuits in base station 210 may be similar or identical in description and circuitry. In addition, the blocks described represent logical functional separation. The blocks may be maintained as separate physical elements or may be combined into larger submodules. The block may also be incorporated into one or more integrated circuits.

Antenna 310 provides a physical layer medium interface that uses radio wave propagation signals to communicate with a base station or other CPE. The antenna 310 has a bidirectional interface connection with the propagating radio wave signal as an electrical signal to the transmit / receive (T / R) switch 320. The T / R switch 320 preferably has two switching states that control whether the signal is directed to the antenna 310 or directed from the antenna 310. Typically, the T / R switch 320 is a single pole double throw (SPDT) type switch, as is well known to those skilled in the art, a plurality of electrical circuits such as diodes, transistors or gates. It may be configured using components and components.

When the T / R switch 320 is switched to the reception state, the radio wave propagation signal received by the antenna 310 is directed through the T / R switch 320 to the receiver / demodulator 330 connected to the T / R switch 320. Provided. The receiver / demodulator 330 has a circuit that amplifies the received signal, converts the frequency, filters it, and demodulates it. In a preferred embodiment, the receiver / demodulator 330 processes the received signal by first amplifying and filtering the received signal. The receiver / demodulator 330 may also convert the received signal from its received frequency to a second frequency that allows good signal demodulation. The receiver / demodulator 330 may also demodulate the received signal after the signal has been amplified, filtered and converted according to the signal standard. In a preferred embodiment, the demodulator can perform OFDM demodulation according to the signal standard used in WRAN. The output signal representing the digital data stream is provided for further processing in a circuit (not shown) such as a data signal processor.

When the T / R switch 320 is switched to the transmit state, the antenna 310 is connected to the modulator / transmitter 340 through the T / R switch 320. The modulator / transmitter 340 has a circuit that interfaces the input data signal to the modulator, and may have circuits such as an amplifier, a filter, a mixer, and an oscillator. The modulator / transmitter 340 receives an input digital data signal from a signal processing circuit (not shown) such as a data signal processor. The modulator / transmitter 340 modulates the input data signal and produces a modulated signal. In a preferred embodiment, the modulator / transmitter 340 modulates the input digital data signal to form an OFDM signal according to the signal standard used for WRAN. The modulator / transmitter 340 may also frequency convert the modulated signal to a frequency suitable for final transmission as a propagating radio wave signal at the antenna 310. The modulator / transmitter 340 may also filter and amplify the converted signal in order to further tune and prepare the signal for transmission. The output transmit signal from the modulator / transmitter 340 is provided to the T / R switch 320. The T / R switch 320 switched to the transmission state provides a transmission signal to the antenna 310 for propagation.

The antenna 310 may also provide an antenna transmission control signal. In a preferred embodiment, the antenna transmission control signal may be generated based on the particular orientation of the antenna 310. The particular orientation of the antenna 310 may generate a particular radiation pattern of polarization, such as a particular polarization of the radiation pattern. Generating and maintaining the proper polarization of the radiation pattern can result in eliminating or reducing unwanted signal interference between two services that share a common spectrum of frequencies. If the antenna 310 does not generate the proper radiation polarization due to improper antenna orientation, there may be an error condition at the antenna 310. As described in detail below, the error condition is used by the antenna 310 to generate the antenna transmission control signal.

The antenna transmission control signal from the antenna 310 may be connected to the T / R switch 320 and operated so as to change the operation of the T / R switch 320. In a preferred embodiment, the antenna transmission control signal may prevent the T / R switch from switching to the transmission state when an error state is detected at the antenna 310.

The controller 350 connects to the T / R switch 320, the receiver / demodulator 330 and the modulator / transmitter 340. The controller 350 provides a control signal to operate or tune the frequency conversion circuit at the receiver / demodulator 330 or the modulator / transmitter 340. The controller 350 also controls the demodulation operation on the receiver / demodulator 330 and the modulation operation on the modulator / transmitter 340, allowing changes in different signal standards, including signal bandwidth, error correction or signal format. May be good.

The controller 350 may also receive signals indicating a state or error condition from the receiver / demodulator 330 and the modulator / transmitter 340, or may receive commands to pass to other circuits. The controller 350 also controls the switching state during the normal operation of the T / R switch 320. The control of the T / R switch 320 may be controlled by a command passed to the controller 350, or may be activated by the controller 350 based on controlling other blocks. As mentioned above, the error condition may allow the antenna transmission control signal from the antenna 310 to disable the control of the T / R switch 320 by the controller 350. The controller 350 may be a separate component, incorporated into a signal processing circuit (not shown), or even incorporated into a large processor used for the entire CPE, as shown in FIG. Good.

With reference to FIG. 4, a block diagram 400 of another embodiment of the transceiver using the embodiment of the present invention is shown. The antenna 410, the receiver / demodulator 430 and the modulator / transmitter 440, and the controller 450 have the same functions as those described above in FIG. 3, and are not described further here. In FIG. 4, the antenna 410 is directly connected to the receiver / demodulator 430 and the modulator / transmitter 440. Direct connections are common in transceiver systems that use half-duplex or full-duplex communication, as opposed to the simplex communication transceivers described above. The antenna transmission control signal from the antenna 410 is provided to the controller 450. The controller 450 may provide transmit enable and disable control directly to the modulator / transmitter 440.

The controller 450 may adjust the transmit signal power or signal level of the modulator / transmitter 440. Tuning the transmit signal power involves incorporating an attenuation circuit or adjusting the signal gain of one or more transmit amplifiers, even if implemented within the modulator / transmitter 440 using multiple known techniques. Good. In this way, the transceiver may continue to transmit with reduced power conditions. The reduced power state may be determined based on the signal state of the local broadcaster so that there is no interference or interference is minimized to acceptable levels.

Note that the described system utilizes a common antenna to transmit and receive signals during communication with the base station or other CPE equipment, although separate antennas may be used for transmission and reception. Should. In configurations where separate antennas are used, the transmitting antenna produces an antenna transmission control signal. The antenna transmission control signal may be provided to the controller or the modulator / transmitter block to perform the same operating functions as described above.

It should also be noted that transmitter control based on antenna orientation may be achieved using alternative systems that may use control signals supplied by different elements other than the antenna. For example, a mobile device or handheld device may have a receiver and an antenna that maintain a static mechanical relationship between the housing of the handheld device and the antenna. The transmitter control switch may be included as part of the housing rather than as part of the antenna, still enabling similar functionality and resulting in control of the antenna transmitter based on antenna orientation.

With reference to FIGS. 5a and 5b, FIG. 500 of an embodiment of a transmitter control switch using an embodiment of the present invention is shown in two different orientations. The drawings show an antenna such as the antenna 310 described above and a position sensitivity switch that can be included as part of the antenna mounting structure. The conductive tube 510 has a connection line attached to the outer surface that connects to a monitoring circuit (not shown). The conductive tube 510 may be part of an actual antenna (such as part of a dipole radiating element) or may be attached separately to the antenna or mounting structure as in a non-radiating structure. In a preferred embodiment, the conductive tube 510 is part of a mounting board of the antenna structure.

The insulating support 520 is mounted inside the conductive tube 510. The conductive weight 530 is suspended from the insulating support 520 using a wire attached to the insulating support 520. The conductor exits the inside of the conductive tube 510 through the insulating hole 512 after being attached to the insulating support 520. The conductors are connected to the monitoring circuit, similar to the connecting wires attached to the conductive tube 510. The connecting wire and the conducting wire connected to the conductive tube 510 form a circuit for generating the above-mentioned antenna transmission control signal. The monitoring circuit (not shown) may have the circuitry included in the T / R switch described above, or may be part of a large controller built into the transceiver used for the WRAN described above.

The conductive weight 530 may be suspended from the insulating support 520 by a lead wire and freely move or rotate in response to a change in the orientation of the conductive tube 510. For example, the conductive weight 530 and the conductor may maintain their orientation along the vertical axis only under the influence of gravity. The conductive tube 510 in FIG. 5a is shown in the horizontal orientation. Since the conductive weight 530 does not contact the side surface of the conductive tube 510, the circuit between the connecting wire and the conducting wire is not completed. FIG. 5b shows the conductive tube 510 in a rotational orientation such that the conductive tube 510 is no longer in the vertical orientation. The conductive weight 530 contacts the inner surface of the side surface of the conductive tube 510. The conductive weight 530 in contact with the side surface of the conductive tube 510 completes or closes the circuit between the conductor and the connecting wire. The presence of this closed circuit may be detected by a monitoring circuit.

Changes in state between open and closed circuits in antenna transmitter control provide improper antenna orientation. The change of state may be used to avoid the operation of the transmitter on the transceiver. Alternatively, state changes may also be used to control or reduce transmitter power. The change in state may also be used to indicate that a service is needed. For example, the service provider may be informed that the service is needed, the antenna is at the wrong angle, and the service may be needed.

Along with the inner diameter of the conductive tube 510, the length of the pendulum formed by the conductive weight 530 and the conductor is the misalignment or misalignment of the antenna structure before the conductive weight 530 and the conductive tube 510 come into contact with each other. The amount of may be determined. For example, the pendulum is designed to allow 10 degrees misalignment from the proper antenna orientation before the conductive weight 530 contacts the conductive tube 510 and closes the circuit between the conductor and the connecting wire. May be good.

Although it is desirable to achieve perfect orientation, near perfect orientation can still result in high levels of coherent polarization separation. For antennas capable of generating polarized radiation patterns in the vertical or horizontal orientation, the separation of coherent polarization is proportional to the cosine of the angle between the unwanted radiation polarization pattern and the desired signal antenna. If the angle is 90 degrees, the separation is infinite. However, if the angle is 78.5 degrees, the separation drops to 14 dB. In the embodiments described, achieving 14 dB of coherent polarization separation between the local broadcaster's transmit signal and the WRAN's transmit signal allows antenna orientation errors where the pendulum structure is not greater than about 5-10 degrees. Request to do.

With reference to FIG. 6, a flowchart showing an exemplary process 600 for controlling transmission using the embodiments of the present invention is shown. The process may be used to control the operation of transmitter control circuits used in transceivers operating in WRAN. The flow chart has steps showing the complete process based on a particular embodiment of the method. Those skilled in the art will recognize that multiple steps may be omitted or replaced to accommodate different embodiments.

At step 610, initialization is performed. Initialization step 610 may be performed in an apparatus such as CPE240 and may have an initial power-on and / or software boot, and may also have a plurality of self-checking operations. The initialization step 610 may further include receiving an initialization signal. The received initialization signal may be transmitted from the base station, or may be transmitted from another CPE device operating as a repeater as described above. The initialization signal may provide initial information about the preparatory operation in WRAN. Thus, initialization step 610 may be part or all of the initial "association" stage between the CPE and the base station described above. However, step 610 may not be necessary if the CPE device is already in operation, eg communicating with WRAN.

Next, in step 620, the signal is prepared for transmission. Step 620 may have to process the data signal, modulate the data signal with the modulator / transmitter 340 to generate an RF transmit signal, and feed the RF transmit signal to the T / R switch 320. Alternatively, step 620 may have to modulate a pre-formatted signal or test pattern signal stored in memory and supply the modulated test pattern signal to the T / R switch 320. Then, in step 630, the antenna orientation is determined, for example, with respect to the appropriate radiation polarization. Step 630 may occur during step 620, or may occur immediately before or during the actual signal transmission. Step 630 may have to monitor the antenna transmission control signal generated by the antenna 310 and transmitted to the T / R switch 310 or the controller 350.

If the decision in step 630 is affirmative, then in step 640 the signal prepared in step 620 is transmitted. The signal is transmitted and propagated or radiated from the antenna 310 to a base station or other CPE acting as a repeater. If the decision in step 630 is negative, then in step 650 normal transmission is disabled. Normal transmission may be disabled by switching the state of the T / R switch 310 to the receiving state and changing the state to the transmitting state to avoid emitting a signal. Alternatively, disabling or avoiding normal transmission may include powering down or disabling the transmitter circuit of the modulator / transmitter 340. Further, step 650 may include reducing the transmit signal power by modifying the amplification at the modulator / transmitter 340.

Finally, in step 660, an error state indication may be provided. The instructions may have a prompt on the display screen, or an indicator light indicating that an error is present in the transmit function of the CPE 240. The steps of processing beginning in step 620 or 630 may be resumed when the error condition is addressed. Further, the steps beginning with step 620 may be repeated each time the CPE 240 transmits a signal within the WRAN. The method described above adjusts the time of either the initial transmission or the transmission, but it may be possible to continuously monitor the operation of the device. As a result, the device may disable or alter transmission whenever the antenna transmission control signal indicates that an error such as misplacement is present.

Although the embodiments of the present invention may tolerate various modifications and alternative embodiments, specific embodiments are illustrated in the drawings as an example and are described in detail herein. However, the present invention is not intended to be limited to the particular form disclosed. Rather, this disclosure covers all modifications, equivalents and alternatives within the gist and scope of the disclosure as defined by the claims.

<figref num="1">Illustrative WRAN block diagram</figref><figref num="2">Block diagram of an exemplary system used in WRAN</figref><figref num="3">Block diagram of an embodiment of a transceiver using an embodiment of the present invention</figref><figref num="4">Block Diagram 400 of Other Examples of Transceivers Using Examples of the Invention</figref><figref num="5a">Diagram of an example of a transmitter control switch using the embodiment of the present invention in the first orientation.</figref><figref num="5b">Diagram of a transmitter control switch embodiment using the embodiment of the present invention in the second orientation.</figref><figref num="6">A flowchart illustrating an exemplary process of controlling transmission using an embodiment of the present invention.</figref>