WO2001073971A2 - A method and apparatus for optimizing the usage of an antenna array beamforming technique - Google Patents
A method and apparatus for optimizing the usage of an antenna array beamforming technique Download PDFInfo
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- WO2001073971A2 WO2001073971A2 PCT/IB2001/000495 IB0100495W WO0173971A2 WO 2001073971 A2 WO2001073971 A2 WO 2001073971A2 IB 0100495 W IB0100495 W IB 0100495W WO 0173971 A2 WO0173971 A2 WO 0173971A2
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
- H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
- H04B7/0842—Weighted combining
- H04B7/086—Weighted combining using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
Definitions
- the present invention relates to wireless telecommunication systems, and more particularly to the use of antenna arrays in wireless telecommunication systems.
- a broadcast by the base site to an active subscriber unit can interfere with a broadcast to another active subscriber unit.
- the interference can cause unacceptable degradation of the radio frequency (RE) signal received by the subscriber unit, resulting in diminished performance and possibly a dropped call.
- RE radio frequency
- methods have been developed for adaptively forming an antenna array beam pattern that results in a more focused broadcast of a signal to the intended subscriber unit and reduced interference with other active subscriber units using the same base site and antenna array.
- a number of these techniques provide for focusing an antenna array beam in the direction of maximum received (by the base site from the subscriber unit) signal strength. That is, the techniques determine a separate amplitude and phase adjustment for each portion of a signal received from a subscriber unit via each of the multiple antennas before the signal portions are combined, thereby allowing the base site to resolve the received signal and interfering signals, nulling out the interfering signals and optimizing the received signal.
- the base site transmits a signal to the subscriber unit
- the amplitude and phase adjustments that are determined based on the received signal are in rum applied to each portion of the signal that is being transmitted by each of the multiple antennas.
- an antenna beam for the purpose of broadcasting a signal to a subscriber unit.
- a subscriber unit might be located behind an obstruction, with the result that a signal focused in the direction of maximum received signal strength, which is the perceived direction of the subscriber unit, is instead merely focused on an edge of the obstruction.
- a widely broadcast signal will more easily diffuse around the obstruction than a narrowly beamed signal and will have a better chance of reaching the subscriber unit than the beamed signal.
- Another situation where a focused beam is disadvantageous is when the subscriber unit is located in an environment where fading makes it exceedingly difficult to determine a location of the subscriber unit based on received signal strength. A beamed signal may end up being targeted in the wrong direction.
- a subscriber unit may be operating at a declining power level due to problems with the unit's power source and will not be able to acceptably receive a slightly misdirected beamed signal. Therefore, a need exists for a method and apparatus that provides a determination of when a situation is appropriate for employment of an antenna array beamforming technique.
- the present invention provides a method and apparatus for optimizing a usage of an antenna array beamforming technique.
- the communication device determines a bearing from the communication device to a communication unit and determines a direction of arrival of a signal received from the communication unit by the communication device via each of the multiple antennas.
- the communication device compares the bearing to the direction of arrival, determines a difference between the two, and compares the determined difference to a predetermined difference threshold.
- the communication device determines whether to employ an antenna array beamforming technique based on the comparison of the determined difference to the predetermined difference threshold.
- the communication device determines a distance between the base site and the communication unit and compares the determined distance to a predetermined distance threshold. The communication device then determines whether to employ an antenna array beamforming technique based on the comparison of the determined distance to the predetermined distance threshold. In another alternative embodiment, the communication device determines multiple signal quality metrics based on multiple signals received from the communication unit, compares the multiple signal quality metrics to each other, and determines whether to employ an antenna array beamforming technique based on the comparison of the multiple signal quality metrics.
- the present invention optimizes the usage of the antenna array beamforming technique by determining to employ a maximum beamwidth broadcast in an environment where a misdirected beamed signal may not be acceptably received by the communication unit and determining to employ an antenna array beamforming technique in an environment where a beamed signal can be acceptably directed to the communication unit.
- FIG. 1 is a block diagram of a wireless telecommunication system in accordance with a preferred embodiment of the present invention.
- FIG.2 is a block diagram of a base site of FIG. 1 in accordance with a preferred embodiment of the present invention.
- FIG.3 is a block diagram of a communication unit of FIG. 1 in accordance with a preferred embodiment of the present invention.
- FIG.4 is an illustration of the use of vectors to determine whether to employ an antenna array beamforming technique in accordance with a preferred embodiment of the present invention.
- FIG. 5a is a logic flow diagram of the steps executed by a communication device to determine whether to employ an antenna array beamforming technique in accordance with a preferred embodiment of the present invention.
- FIG. 5b is a continuation of FIG. 5a and is a logic flow diagram of the steps executed by a communication device to determine whether to employ an antenna array beamforming technique in accordance with a preferred embodiment of the present invention.
- FIG. 1 is a block diagram of a wireless telecommunication system 100 in accordance with a preferred embodiment of the present invention.
- Wireless telecommunication system 100 includes multiple geographically-diverse communication devices 101 - 103 (three shown), preferably base sites, that are coupled to each other and to a system controller 122 via anetwork 120, such as dedicated Tl phone lines or microwave links.
- the three base sites 101 -103, the system controller 122, and the network 120 are collectively referred to as a fixed infrastructure. Being fixed in place, the precise location of each base site 101-103 is known with high accuracy as determined by surveying or other methods of geographic location determination.
- System controller 122 includes a processor 124, preferably a microprocessor, digital signal processor (DSP), or microcontroller, and associated memory 126 that allows controller 122 to store data, run programs, and make computations.
- memory 126 further includes a location database 128 that includes the locations of all of the base sites 101-103 in system 100.
- location database 128 may be located anywhere in system 100, such as in one of base stations 101 -103, and coupled to the other components of system 100 via network 120.
- Each base site 101 - 103 provides communication service to a respective service coverage area 111-113.
- Each coverage area lll-113 is subdivided into three sectors, that is, coverage area 111 is subdivided into sectors 131-133, coverage area 112 is subdivided into sectors 134-136, and coverage area 113 is subdivided into sectors 137-139.
- Each sector 131-139 spans approximately 120° of a 360° span of the sector's respective coverage area 111-113.
- Each base site 101-103 preferably includes multiple antenna arrays 141-143 (three shown), wherein each antenna array is associated with one of the sectors of the coverage area in which the base site resides.
- each antenna array 141-143 includes multiple directional antennas (i.e., antenna array 141 includes antennas 144, 145 (two shown), antenna array 142 includes antennas 146, 147 (two shown), and antenna array 143 includes antennas 147, 148 (two shown)), resulting in multiple directional antennas being associated with each sector of a coverage area.
- antenna array 141 includes antennas 144, 145 (two shown)
- antenna array 142 includes antennas 146, 147 (two shown)
- antenna array 143 includes antennas 147, 148 (two shown)
- FIG.2 is ablock diagram of a base site 101-103 in accordance with apreferred embodiment of the present invention.
- Each base site 101-103 preferably includes multiple antenna arrays 141- 143 and their associated antennas 144-149.
- Each antenna 144-149 is coupled to a respective receiver unit 204-209 that includes a demodulator 224 coupled to each of a radio frequency (RF) filter 220, a local oscillator 222, and an analog-to-digital converter 226.
- Each receiver unit 204-209 is further coupled to a processor 210, preferably a microprocessor or a digital signal processor (DSP).
- DSP digital signal processor
- Processor 210 and an associated memory 212 preferably a random access memory (RAM), allow the base site to store information, make computations, and run software programs.
- Each base site 101- 103 further includes a timing reference unit 214 coupled to processor 210 that provides a timing reference for the base site and a Global Positioning Satellite (GPS) receiver 216 that is coupled to the timing reference unit 214.
- GPS Global Positioning Satellite
- Each base site 101-103 has access to a common time base which the base site uses to synchronize its timing reference unit 210.
- the common time base is provided by the GPS receiver 212 at each base site 101 - 103, which GPS receiver 212 has access to a GPS satellite signal; however, those of ordinary skill in the art realize that there are.other methods of supplying a highly accurate common time base to each of base sites 101-103, such as a synchronization unit that is connected to the base site via a dedicated Tl link that is a part of the network 120 and that is dedicated to time synchronization, which synchronization unit generates a common time base and supplies the common time base to each of base sites 101 - 103 via the Tl link, or a mobile unit situated at a known location that broadcasts a signal received by each of base sites 101-103 and which signal serves as a synchronizing time base for the base sites, which other methods may be used without departing from the spirit and scope of the present invention.
- Telecommunication system 100 also includes multiple communication units 110, only one of which is shown in FIG. 1.
- Communication unit 110 preferably is a cellular telephone or a radiotelephone and, as shown in FIG, 3, preferably includes an antenna 308, a transmitter 300 and a receiver 302 that are each coupled to antenna 308 and to a microprocessor 304, and a memory 306 coupled to microprocessor 304.
- system controller 122 assigns a base site (e.g., base site 101) to serve as a serving base site for the communication unit 110.
- the serving base site 101 manages and provides radio communication services for communication unit 110 while the communication unit is located in a sector (i.e., sector 131) of serving base site's service coverage area 111.
- base site 101 In order to optimize the strength of an RF signal received by communication unit 110 from base site 101, and to minimize the interference of the RF signal with communications between base site 101 and other active communication units in sector 131 , base site 101 employs an antenna array beamforming technique for the broadcast of the RF signal.
- the antenna array beamforming technique allows base site 101 to broadcast a narrowly focused signal to communication unit 110.
- the employment of an antenna beamforming technique may result in a signal that is beamed in a direction different from the actual direction to communication unit 110.
- the present invention provides a method and apparatus for optimizing a usage of the antenna array beamforming technique by determining whether to employ the antenna beamforming technique or instead to broadcast at maximum beamwidth.
- System 100 determines a geographical location of communication unit 110.
- communication unit 110 which is synchronized with respect to the common time base, transmits a signal to each of base sites 101-103.
- the signal includes an identifier, such as an identifying sequence of symbols, that uniquely corresponds to communication unit 110, and further includes synchronization symbols, pilot symbols, and a time of transmission indication relative to the common time base.
- each of base sites 101-103 determines a time of arrival for the signal and transmits the determined time of arrival to serving base site 101.
- Processor 210 ofbase site 101 queries location database 128 to obtain the locations of base sites 101-103, and determines the location of communication unit 110 based on the base site locations, the time of arrival information received from each of base sites 101-103, and by using triangulation or another geographical intersection techniques that are stored as programs in memory 212. Processor 210 then stores the determined location in memory 212.
- each ofbase sites 101-103 transmits their respectively determined times of arrival to controller 122.
- Processor 124 of controller 122 queries location database 128 to obtain the locations of base sites 101-103, and determines the location of communication unit 110 based on the base site locations, the time of arrival information received from each of base sites 101-103, and by using triangulation or another geographical intersection techniques that are stored as programs in memory 126.
- Controller 122 then conveys the location of commumcation unit 110 to base site 101, where the location is stored in memory 212.
- each base site 101-103 transmits a signal to the communication unit 110 in order to determine a geographical location of communication unit 110.
- Each signal includes an identifier, such as an identifying sequence of symbols, that uniquely corresponds to the base site 101 - 103 transmitting the respective signal.
- Each signal also includes a time of transmission indication relative to the common time base.
- communication unit 110 determines a time difference of arrival for each signal with respect to each of the other signals, and transmits the determined time differences of arrival to controller 122 via one ofbase sites 101-103.
- Processor 124 in controller 122 queries location database 128 to obtain the locations ofbase sites 101-103, and determines the geographical location of communication unit 110 based on the base site locations, the time difference of arrival information received from communication unit 110, and by using triangulation or another geographical intersection techniques that are stored as programs in memory 126. Controller 122 then conveys the location of communication unit 110 to base site 101 , where the location is stored in memory 212.
- communication unit 110 further includes a GPS receiver coupled to microprocessor 304 and antenna 308 and self-determines its geographical location by employing the GPS receiver to receive signals from at least three of a constellation of GPS satellites.
- Communication unit 110 preferably microprocessor 304, then determines its own location based on the satellite signals and in accordance with known techniques of triangulation as applied to GPS systems, which techniques are stored as programs in memory 306.
- Communication unit 110 then conveys the determined location to base site 101, where the location is stored in memory 212.
- Processor 210 in base site 101 determines a distance between base site 101 and communication unit 110.
- Processor 210 executes a distance determination algorithm that is stored in memory 212, or alternately in memory 126, which algorithm utilizes the location ofbase site 101 stored in location database 128 and the determined location of commumcation unit 110 stored in memory 212, or alternately in memory 126.
- Processor 210 also determines a bearing from base site 101 to communication unit 110 based on the two stored locations.
- Processor 210 compares the determined distance to a predetermined distance threshold, for example 150 meters, that is stored in memory 212.
- a predetermined distance threshold Among factors considered in determining a predetermined distance threshold are the average speed of communication units in the sector (i.e., sector 131) and the obstructions existing in the sector, so that when a communication unit is so close to the serving base site that a maximum bandwidth beam has ample energy to reach the communication unit, or is changing locations so quickly that a narrowly focused beam would have to be frequently readjusted, a maximum beamwidth beam is preferred.
- a maximum beamwidth beam is preferred.
- base site 101 determines not to employ an antenna array beamforming technique and to instead broadcast at a maximum beamwidth.
- processor 210 determines whether to employ an antenna array beamforming technique based on the determined location of communication device 110 and a direction of arrival (DOA) of a signal received by base site 101 from communication unit 110, which DOA is determined as described below.
- DOA direction of arrival
- System 100 determines a DOA of a signal received by a base site from a communication unit serviced by the base site as follows.
- a communication unit i.e., communication unit 110 located in a sector (i.e., sector 131) serviced by a serving base site (i.e., base site 101) is allocated a communication channel, preferably including a frequency bandwidth, for radio frequency (RF) communications between communication unit 110 and base site 101.
- Communication unit 110 transmits an RF signal 150 in the allocated communication channel to base site 101, which RF signal 150 is available for reception at each ofthe multiple antennas 144, 145 of antenna array 141.
- RF radio frequency
- Signal 150 is received by a first antenna 144 ofthe multiple antennas 144, 145 of antenna array 141 to produce a first received signal, and by a second antenna 145 ofthe multiple antennas 144, 145 to produce a second received signal.
- Antenna 144 conveys the first received signal to a first receiver unit 204 ofthe multiple receiver units 204-209 and antenna 145 conveys the second received signal to a second receiver unit 205 ofthe multiple receiver units 204-209.
- the first received signal is conveyed to an RF filter 220, where out-of- band noise is removed from the signal to produce a first filtered signal.
- the first filtered signal is conveyed to a demodulator 224, along with a reference signal that is generated by a local oscillator 222.
- the frequency ofthe reference signal is approximately a frequency of signal 150.
- Demodulator 224 mixes the first filtered signal with the reference signal to produce a first baseband signal.
- the first baseband signal is conveyed to an A/D 226 that digitizes the first baseband signal to produce a first digitized baseband signal.
- Receiver unit 204 then conveys the first digitized baseband signal to processor 210.
- the second received signal is conveyed to an RF filter 220, where out-of-band noise is removed from the signal to produce a second filtered signal.
- the second filtered signal is conveyed to a demodulator 224, along with a reference signal that is generated by a local oscillator 222.
- the frequency ofthe reference signal is approximately a frequency of signal 150.
- Demodulator 224 mixes the second filtered signal with the reference signal to produce a second baseband signal.
- the second baseband signal is conveyed to an A/D 226 that digitizes the second baseband signal to produce a second digitized baseband signal.
- Receiver unit 206 then conveys the second digitized baseband signal to processor 210.
- processor 210 Upon receiving each ofthe first digitized baseband signal and the second digitized baseband signal, processor 210 determines a time of arrival (TOA), or alternatively a phase of arrival, for each of the first received signal and the second received signal.
- TOA time of arrival
- Each TOA or phase of arrival determination is made with reference to the common time base and is based on known delays in the path of each ofthe first and second received signals from the respective receiving antennas 144, 145 to processor 210, which delays are stored in memory 212.
- Processor 210 determines a direction of arrival (DOA) for signal 150 by executing a DOA algorithm stored in memory 212.
- the DOA algorithm determines a DOA for signal 150 based on the TOA determinations for each ofthe first and second received signals and further based on a predetermined spatial separation and directional alignment of each ofthe multiple antennas 144, 145 in array 141 with respect to the other antennas in the array.
- the spatial separation, preferably one-half wavelength, and directional alignment of each of multiple antennas 144, 145 are stored in memory 212.
- the DOA algorithm may determine a DOA for signal 150 based on a phase of the signal as received at each of multiple antennas 144, 145 and the predetermined spatial separation and alignment of each ofthe multiple antennas.
- One such algorithm, used in the preferred embodiment, is an Estimation of Signal Parameters via Rotational Invariance Techniques (ESPRIT) algorithm, which algorithm is described in the paper "ESPRIT- Estimation of Signal Parameters via Rotational Invariance Techniques," IEEE Transactions on Accoustics, Speech, and Signal Processing, vol. 37, no. 7, July 1989.
- Another algorithm that may be used here is Multiple Signal Identification and Classification (MUSIC).
- Processor 210 then conveys the determined DOA to memory 212, where the determined DOA is stored in a data array.
- processor 210 receives a signal from communication unit 110 via each of the multiple antennas 144, 145 of array 141, determines a DOA for the received signal, and stores the DOA in memory 212, are repeated every 1.25 milliseconds (ms).
- processor 210 determines a DOA mean and a DOA variance, based on the accumulated DOA determinations, by executing a statistical analysis program that is stored in memory 212.
- the DOA mean constitutes an estimated geographical direction from base site 101 to communication unit 110 based on an incoming direction ofthe signals received by base site 101 from communication unit 110.
- System 100 compares the estimated geographical direction to communication unit 110 from base site 101 to the determined bearing from base site 101 to communication unit 110, determines a difference between the estimated geographical direction and the determined bearing, and compares the determined difference to a difference threshold.
- FIG. 4 illustrates the use of vectors to make the comparison and to determine the difference, and is presented herein for the purpose of better enabling the reader to understand the principles ofthe invention.
- Processor 210 determines a first vector 404 extending from base site 101 toward the determined geographical location of communication unit 110 (i.e., the determined bearing from base site 101 to communication unit 110) and a second vector 406 extending from base site 101 in the direction of the estimated geographical direction to communication unit 110.
- Processor 210 determines an angular difference 408 (i.e., a cross-angle) between first vector 404 and second vector 406.
- Processor 210 compares cross-angle 408 to a predetermined angular threshold.
- a value for the predetermined angular threshold is based on a desire to maximize the probability of reaching a communication unit with a transmitted signal and a desire to minimize the probability of interfering with other broadcasts in a sector (i.e., sector 131).
- Factors such as a traffic level in sector 131, geographical features (such as hills and buildings) ofthe sector, a signal propagation model used to characterize a propagation of a signal in sector 131, and the number of antennas in an antenna array may be considered in selecting a predetermined angular threshold.
- antenna array 141 includes two antennas, a cross-angle of approximately 80° may be appropriate, while if antenna array 141 includes four antennas, a cross-angle of approximately 50° ma be appropriate since the antenna array is capable of transmitting a more narrowly focused beam when the array includes a greater number of antennas.
- cross-angle 408 When cross-angle 408 is greater than the predetermined angular threshold, then base site 101 determines not to employ an antenna array beamforming technique and to instead broadcast at a maximum beamwidth. However, when cross-angle 408 is less than or equal to the predetermined angular threshold and, as detailed above, the determined distance between between base site 101 and the determined geographical location of communication unit 110, shown in FIG. 4 as determined distance 402, is greater than the predetermined distance threshold, then processor 210 determines whether to employ an antenna array beamforming technique based on a signal quality metric rate of change as described below.
- the signal quality metric rate of change is based on multiple determinations of a signal quality metric, which signal quality metric is determined as follows.
- each base site 101 - 103 further includes a signal summer 230 coupled to a means for analyzing a spectrum of an RF input signal 232, preferably a spectrum analyzer for analyzing the spectrum of received RF signal 150, which summer 230 and spectrum analyzer 232 preferably are each included in processor 210.
- the first digitized baseband signal, which is derived from the first received signal, and the second digitized baseband signal, which is derived from the second received signal, are combined in summer 230 to produce a combined baseband signal.
- the combined baseband signal is then fed to spectrum analyzer 232 and a signal quality metric, preferably a signal-to-noise ratio (SNR), is determined.
- SNR signal-to-noise ratio
- the SNR is determined by spectral analysis techniques.
- the spectrum of the combined baseband signal is analyzed in spectrum analyzer 232.
- the functions of spectrum analyzer 232 are performed by processor 210, which performs a fast Fourier transform (FFT) on the combined baseband signal in order to determine the combined baseband signal's frequency components and their magnitudes.
- the magnitudes ofthe frequency components are then used to calculate the total power, preferably in decibels referenced to a milliwatt (dBm), in the communication channel and in upper and lower frequency bands adjacent to the communication channel.
- Processor 210 then calculates a ratio ofthe in-band and adjacent band total power levels to produce a SNR, and stores the SNR in memory 212.
- base site 101 periodically, preferably once every 0.4 second, determines and stores a signal quality metric, as described above, for signals received from communication unit 110.
- processor 210 compares each newly determined signal quality metric (i.e., SNR) to an immediately preceding signal quality metric determination and determines a signal quality metric rate of change (i.e., a rate of change in the SNR's) based on a difference between the two signal quality metrics.
- Processor 210 then compares the determined signal quality metric rate of change to a predetermined signal quality metric rate of change threshold.
- the rate of change threshold is determined by the designer of system 100, preferably based on factors such as the traffic pattern and traffic level in the sector (i.e., sector 131), and the number of obstructions in the sector. Those who are ordinary skill in the art realize that a variety of values may be used for the predetermined rate of change threshold without departing form the spirit and scope ofthe present invention.
- the predetermined rate of change threshold is the maximum rate of signal quality deterioration tolerated by system 100, due to fading or obstructions or a variety of other factors, beyond which system 100, preferably base site 101 , will not employ an antenna array beamforming technique.
- Processor 210 to subtracts a newly determined signal quality metric from a preceding signal quality metric determination to determine a signal quality metric rate of change. If the difference is greater than the predetermined rate of change threshold, then processor 210 employs a maximum beamwidth for transmissions to communication unit 110.
- the determined rate of change (10 dBm per second) is compared to a predetermined rate of change threshold, for example '8 dBm per second.
- processor employs a maximum beamwidth for transmissions to communication unit 110.
- processor 210 determines to employ an antenna array beamforming technique.
- Antenna beamforming techniques are well-known in the art. Many are based on focusing an antenna beam in the direction of maximum received (by base site 101 from communication unit 110) signal strength.
- base site 101 employs an antenna beamforming technique described in U.S. patent 5,936,569, "Method and Arrangement for Adjusting Antenna Pattern," which patent has been assigned to the assignee of the present invention and is hereby incorporated herein.
- the technique used to determine a pattern of an antenna beam is not critical to the present invention, and those who are of ordinary skill in the art realize that any one of numerous beamforming methods may be used here without departing from the spirit and scope ofthe present invention.
- the preferred embodiment ofthe present invention considers three determined differences between factors determined by system 100 and each of three predetermined thresholds before determining to employ an antenna array beamforming technique.
- system 100 preferably base site 101, deteremines whether to employ an antenna array beamforming technique based on any one of the three determined differences. That is, base site 101 may determine to employ an antenna array beamforming technique when determined distance 402 is greater than the predetermined distance threshold and to employ a maximum beamwidth broadcast when determined distance 402 is less than or equal to the predetermined distance threshold.
- base site 101 may determine to employ an antenna array beamforming technique when cross-angle 408 is less than or equal to the predetermined angular threshold and to employ a maximum beamwidth broadcast when cross-angle 408 is greater than the predetermined angular threshold.
- base site 101 may determine to employ an antenna array beamforming technique when the determined signal quality metric rate of change is less than or equal to the predetermined signal quality metric rate of change threshold and to employ a maximum beamwidth broadcast when the determined signal quality metric rate of change is greater than the predetermined signal quality metric rate of change threshold.
- the present invention seeks to optimize a probability that a signal transmit by base site 101 will be received by communication unit 110 while minimizing the potential for interference of the broadcast to communication unit 110 with broadcasts to other communication units in sector 131, thereby optimizing a usage ofthe antenna array beamforming technique.
- a difference between the bearing from base site 101 to communication unit 110 and the direction of arrival of signals received from communication unit 110 that exceeds a predetermined threshold indicates that an antenna array beamforming technique, which focuses an antenna array beam in the direction of maximum received signal strength, would result in a misdirected antenna beam. In such an instance, use of a maximum antenna beamwidth would better assure reception by communication unit 110 of a signal transmitted by base site 101.
- base site 101 can determine whether a communication unit is unable to acceptably receive a slightly misdirected beamed signal, for example because the communication unit has passed behind a building or is passing through an urban canyon, and a diffraction or diffusion of a maximum beamwidth broadcast may be more appropriate.
- a maximum beamwidth broadcast should have ample energy for reaching communication unit 110 whereas a narrowly focused beam may not be able to keep up with the movements of communication unit 110.
- FIG. 5 is a logic flow diagram 500 of the steps executed by a communication device to determine whether to employ an antenna array beamforming technique and thereby optimize the usage ofthe antenna array beamforming technique in accordance with a preferred embodiment ofthe present invention.
- the communication device is a base site that includes an antenna array that includes multiple antennas.
- the communication device further includes multiple receiver units wherein each antenna of the multiple antennas is coupled to a separate receiver unit of the multiple receiver units, a processor coupled to each of the multiple receiver units, and a memory coupled to the processor.
- the logic flow begins (501) when the communication device, preferably a base site, determines (502) a location of a communication unit, preferably a cellular telephone or a radiotelephone.
- the communication device determines the location ofthe communication unit based on a time of arrival of a signal at each of multiple communication devices and by reference to a location database that stores the geographical location of each of the multiple communication devices.
- the communication device determines (503) its own location, preferably by reference to the location database, and determines (504) a distance between the location ofthe communication device and the location of the communication unit.
- the communication device compares (505) the determined distance to a predetermined distance threshold, and determines (506) whether to employ an antenna array beamforming technique.
- the communication device determines (507) to broadcast at a maximum beamwidth, and the logic flow ends (508).
- the communication device also determines a direction of arrival (DOA) before determining to employ an antenna array beamforming technique.
- DOA direction of arrival
- the communication device receives (509) a signal from the communication unit via a first antenna ofthe multiple antennas to produce a first received signal, and receives (510) the signal from the communication unit via a second antenna of he multiple antennas to produce a second received signal.
- the communication device determines (511) a DOA ofthe signal based on the first received signal and the second received signal.
- the communication device determines a time of arrival ofthe first received signal and a time of arrival ofthe second received signal.
- the communication device determines a phase ofthe first received signal and a phase ofthe second received signal.
- the communication device determines a DOA ofthe signal by executing a DOA algorithm stored in the memory and based on the determined times of arrival, or alternately the phases, of the first and second received signals.
- the determined DOA ofthe signal constitutes an estimated geographical direction to the communication unit from the communication device based on the signal received by the communication device from the communication unit.
- the communication device determines (512) a bearing from the communication device to the determined location ofthe communication unit and then compares (513) the bearing to the DOA of the signal.
- the communication device determines a first vector based on the bearing and determines a second vector based on the DOA.
- the communication device compares the two vectors and determines (514) a difference between the bearing and the DOA based on the comparison ofthe two vectors, which difference is determined as an angular difference (i.e., a cross-angle) between the two vectors.
- the communication device compares (515) the determined difference between the first and second vectors, that is the cross-angle, to a predetermined difference threshold, preferably a predetermined angular threshold, and, based on the comparison, determines (516) whether to employ an antenna array beamforming technique.
- a predetermined difference threshold preferably a predetermined angular threshold
- the communication device further determines a signal quality metric rate of change before determining to employ an antenna array beamforming technique.
- the communication device receives (518) a first signal of multiple signals transmitted to the communication device by the communication unit and determines (519) a first signal quality metric based on the first signal.
- the communication device also receives (520) a second signal ofthe multiple signals and determines (521) a second signal quality metric based on the second signal, wherein the second signal is different from the first signal.
- the first and second signal quality metrics are each a signal-to-noise ratio (SNR); however, those of ordinary skill in the art realize that other signal quality metrics may be used here, such as signal power or bit rate error, without departing from the spirit and scope ofthe present invention.
- the communication device compares (522) the first signal quality metric to the second signal quality metric and determines (523) a signal quality metric rate of change based on the comparison ofthe first and second signal quality metrics.
- the communication device compares (524) the signal quality metric rate of change to a predetermined signal quality metric rate of change threshold and determines (525) whether to employ an antenna array beamforming technique.
- the predetermined rate of change threshold is the maximum rate of signal quality deterioration tolerated by the communication device, due to fading or obstructions or a variety of other factors, before the communication device determines not to employ an antenna array beamforming technique.
- the communication device employs (526) a maximum beamwidth broadcast and the logic flow ends (508).
- the communication device When the determined rate of change is less than or equal to the predetermined rate of change threshold, and the deteremined distance is greater than the determined distance threshold, and the angular difference is less than or equal to the predetermined angular threshold, the communication device employs (527) an antenna beamforming technique and the logic flow ends (508).
- the preferred embodiment ofthe present invention compares each of three determinations (i.e., the determined distance to the communication unit, the determined difference between the bearing to the communication unit and the DOA, and the determined signal quality metric rate of change) to three respective thresholds (i.e., the predetermined distance threshold, the predetermined difference threshold, and the predetermined signal quality metric rate of change threshold) before determining to employ an antenna array beamforming technique.
- three respective thresholds i.e., the predetermined distance threshold, the predetermined difference threshold, and the predetermined signal quality metric rate of change threshold
- step (506) the antenna array broadcasts (507) at maximum bandwidth and the logic flow ends
- the antenna array employs an antenna beamforming technique (step (527)) and the logic flow ends.
- a communication device executes steps (502), and (509)-(516). Then, when the determined difference between the location of the communication device and the DOA is greater than the predetermined difference threshold (step (516)), the antenna array broadcasts (517) at maximum bandwidth and the logic flow ends (508). When the determined distance is less than or equal to the predetermined difference threshold (step (516)), the antenna array employs an antenna beamforming technique (step (527)) and the logic flow ends (508).
- a communication device executes steps (518)-(525). Then, when the determined difference between the location ofthe communication device and the DOA is greater than the predetermined difference threshold (step (525)), the antenna array broadcasts (526) at maximum bandwidth and the logic flow ends (508). When the determined distance is less than or equal to the predetermined difference threshold (step (525)), the antenna array employs (527) an antenna beamforming technique and the logic flow ends (508).
- the present invention provides a method and apparatus for optimizing the usage of the antenna a ⁇ ay beamforming technique by determining whether to employ an antenna array beamforming technique for a broadcast of an RF signal by a communication device, preferably a base site, to a communication unit.
- the base site includes an antenna a ⁇ ay, which antenna array includes multiple antennas.
- the base site determines a geographical location ofthe communication unit, a bearing from the base site to the determined location ofthe communication unit, and a DOA of a signal received by the base site from the communication unit via each ofthe multiple antennas.
- the base site compares the bearing to the DOA, determines a difference based on the comparison, and compares the determined difference to a predetermined difference threshold.
- the base site also determines a distance between the base site and the communication unit, and compares the determined distance to a predetermined distance threshold.
- the base site also determines multiple signal quality metrics based on signals received from the communication unit, determines a signal quality metric rate of change based on the multiple signal quality metrics, and compares the determined signal quality metric rate of change to a predetermined signal quality metric rate of change threshold. Based on the comparisons ofthe determined difference, the determined distance, and the determined signal quality metric rate of change to each of their respective thresholds, the base site determines whether to employ an antenna array beamforming technique.
- a base site optimizes a probability that a signal transmit by the base site will be received by the communication unit while minimizing the potential for interference of the broadcast to the communication unit with broadcasts to other communication units.
- the present invention optimizes a usage ofthe antenna a ⁇ ay beamforming technique by providing for the employment of a maximum beamwidth broadcast in an environment where fading or the presence of obstructions between the communication unit and the base site result in a misdirected beamed signal when an antenna a ⁇ ay beamforming technique is employed, which misdirected beamed signal may not be acceptably received by the communication unit.
- the present invention optimizes the usage ofthe antenna a ⁇ ay beamforming technique by employing the antenna a ⁇ ay beamforming technique, which results in a beamed signal that provides minimum interference with broadcasts to nearby communication units.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2001571574A JP2003529276A (en) | 2000-03-28 | 2001-03-23 | Method and apparatus for optimizing the use of antenna array beamforming techniques |
EP01919685A EP1277292B1 (en) | 2000-03-28 | 2001-03-23 | A method and apparatus for optimizing the usage of an antenna array beamforming technique |
DE60130548T DE60130548T2 (en) | 2000-03-28 | 2001-03-23 | METHOD AND DEVICE FOR OPTIMIZING THE UTILIZATION OF AN ANTENNA ARRAY BEAMING TECHNIQUE |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/537,049 | 2000-03-28 | ||
US09/537,049 US6369756B1 (en) | 2000-03-28 | 2000-03-28 | Method and apparatus for optimizing the usage of an antenna array beamforming technique |
Publications (2)
Publication Number | Publication Date |
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WO2001073971A2 true WO2001073971A2 (en) | 2001-10-04 |
WO2001073971A3 WO2001073971A3 (en) | 2002-06-20 |
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PCT/IB2001/000495 WO2001073971A2 (en) | 2000-03-28 | 2001-03-23 | A method and apparatus for optimizing the usage of an antenna array beamforming technique |
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US (2) | US6369756B1 (en) |
EP (1) | EP1277292B1 (en) |
JP (1) | JP2003529276A (en) |
KR (1) | KR100669985B1 (en) |
AT (1) | ATE373901T1 (en) |
DE (1) | DE60130548T2 (en) |
WO (1) | WO2001073971A2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008077113A1 (en) * | 2006-12-19 | 2008-06-26 | Airgain, Inc. | Optimized directional mimo antenna system |
EP3487224A4 (en) * | 2016-08-12 | 2019-05-22 | Huawei Technologies Co., Ltd. | Method for switching signal transmission mode, base station and terminal device |
Families Citing this family (41)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6369756B1 (en) * | 2000-03-28 | 2002-04-09 | Nokia Networks Oy | Method and apparatus for optimizing the usage of an antenna array beamforming technique |
US7313391B2 (en) * | 2000-09-26 | 2007-12-25 | Andrew Corporation | Modeling of RF point source reference for analysis of wireless signal propagation |
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US7529537B2 (en) * | 2001-05-14 | 2009-05-05 | International Business Machines Corporation | System and method for providing personal and emergency service hailing in wireless network |
US20030114169A1 (en) * | 2001-12-14 | 2003-06-19 | Hitachi, Ltd. | Method and system for detecting the position of mobile station |
US7755652B2 (en) * | 2002-01-07 | 2010-07-13 | Samsung Electronics Co., Ltd. | Color flat panel display sub-pixel rendering and driver configuration for sub-pixel arrangements with split sub-pixels |
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FI20021094A0 (en) * | 2002-06-07 | 2002-06-07 | Nokia Corp | Ensuring connection in the radio system |
RU2254682C1 (en) * | 2003-10-27 | 2005-06-20 | Общество с ограниченной ответственностью "Алгоритм" | Method for radio communication in wireless local network |
US7428408B2 (en) * | 2004-09-20 | 2008-09-23 | Interdigital Technology Corporation | Method for operating a smart antenna in a WLAN using medium access control information |
US7917176B2 (en) * | 2006-02-14 | 2011-03-29 | Nec Laboratories America, Inc. | Structured codebook and successive beamforming for multiple-antenna systems |
US7570713B2 (en) * | 2006-06-14 | 2009-08-04 | Harris Stratex Networks, Inc. | System and method for anticipatory receiver switching based on signal quality estimation |
US7881752B1 (en) * | 2006-06-19 | 2011-02-01 | Sprint Communications Company L.P. | Hybrid architecture that combines a metropolitan-area network fiber system with a multi-link antenna array |
US7642988B1 (en) | 2006-06-19 | 2010-01-05 | Sprint Communications Company L.P. | Multi-link antenna array configured for cellular site placement |
KR101366332B1 (en) * | 2007-04-19 | 2014-02-21 | 엘지전자 주식회사 | A method of automatic repeat request(ARQ) in communication system |
US7941108B2 (en) * | 2007-06-26 | 2011-05-10 | Cisco Technology, Inc. | Method and system for automatically identifying wireless signal quality of a region |
US8090377B2 (en) * | 2007-06-26 | 2012-01-03 | Cisco Technology, Inc. | Method and system for using signal quality information |
GB2466584A (en) * | 2007-08-31 | 2010-06-30 | Allen Vanguard Technologies Inc | Radio antenna assembly and apparatus for controlling transmission and reception of RF signals |
KR101412174B1 (en) * | 2007-10-17 | 2014-06-26 | 삼성전자주식회사 | Method and apparatus for decoding in portable communication system |
JP5107069B2 (en) * | 2008-01-25 | 2012-12-26 | 株式会社エヌ・ティ・ティ・ドコモ | Base station apparatus and method used in mobile communication system |
US8437769B1 (en) * | 2008-02-19 | 2013-05-07 | Sprint Spectrum L.P. | Method and system for selecting a length of a preamble transmitted in an access probe |
US8738981B2 (en) * | 2008-10-24 | 2014-05-27 | Qualcomm Incorporated | Method and apparatus for H-ARQ scheduling in a wireless communication system |
EP2408249B1 (en) * | 2009-03-09 | 2016-01-06 | Nec Corporation | Rank estimation apparatus, receiver, communication system, rank estimation method, and program recording medium |
CN102484523B (en) | 2009-06-15 | 2015-02-18 | Agc汽车美洲研发公司 | Antenna system and method for optimizing an RF signal |
WO2011131210A1 (en) * | 2010-04-20 | 2011-10-27 | Telecom Italia S.P.A. | Method and system for wireless communications, corresponding network and computer |
GB2483279A (en) * | 2010-09-02 | 2012-03-07 | Skype Ltd | Automatic call re-establishment in dependence upon the condition of the connection. |
JP5742474B2 (en) * | 2011-05-27 | 2015-07-01 | 富士通株式会社 | Wireless communication apparatus, wireless communication system, and wireless communication method |
US9306640B2 (en) * | 2012-09-07 | 2016-04-05 | Qualcomm Incorporated | Selecting a modulation and coding scheme for beamformed communication |
WO2014149201A1 (en) | 2013-03-15 | 2014-09-25 | Agc Automotive Americas R& D, Inc. | Window assembly with transparent regions having a perfoormance enhancing slit formed therein |
WO2015036020A1 (en) * | 2013-09-11 | 2015-03-19 | Huawei Technologies Co., Ltd. | Antenna device and method for controlling focusing of an antenna beam of an antenna array |
KR20160046228A (en) * | 2014-10-20 | 2016-04-28 | 한국전자통신연구원 | Method and apparatus for beamforming |
US9635627B2 (en) * | 2014-11-12 | 2017-04-25 | Nokia Solutions And Networks Oy | Connection reliability and managing interference created by beamforming |
US10720704B2 (en) * | 2015-09-17 | 2020-07-21 | Gilat Satellite Networks Ltd. | Mobile antenna tracking |
US10454553B2 (en) | 2017-03-01 | 2019-10-22 | Samsung Electronics Co., Ltd. | Beam forming method for a transmitting antenna and a device thereof |
US10098085B1 (en) * | 2017-06-05 | 2018-10-09 | Cisco Technology, Inc. | Detecting a location of a wireless device |
US10411765B2 (en) * | 2017-12-22 | 2019-09-10 | Motorola Mobility Llc | Body detection using near field millimeter wave scattering |
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US10701681B1 (en) | 2019-03-29 | 2020-06-30 | At&T Intellectual Property I, L.P. | Coordinated beam forming for 5G or other next generation network |
US11445382B2 (en) | 2020-08-09 | 2022-09-13 | Shenzhen Jaguar Wave Technology Ltd. | Communication zone allocation method of terminal, device therefor, and communication equipment |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5680142A (en) * | 1995-11-07 | 1997-10-21 | Smith; David Anthony | Communication system and method utilizing an antenna having adaptive characteristics |
US5936569A (en) * | 1997-12-02 | 1999-08-10 | Nokia Telecommunications Oy | Method and arrangement for adjusting antenna pattern |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5596330A (en) * | 1992-10-15 | 1997-01-21 | Nexus Telecommunication Systems Ltd. | Differential ranging for a frequency-hopped remote position determination system |
US5844522A (en) * | 1995-10-13 | 1998-12-01 | Trackmobile, Inc. | Mobile telephone location system and method |
US5945948A (en) * | 1996-09-03 | 1999-08-31 | Motorola, Inc. | Method and apparatus for location finding in a communication system |
US6195037B1 (en) * | 1999-06-01 | 2001-02-27 | Motorola, Inc. | Method and apparatus for increased system capacity using antenna beamforming |
US6377636B1 (en) * | 1999-11-02 | 2002-04-23 | Iospan Wirless, Inc. | Method and wireless communications system using coordinated transmission and training for interference mitigation |
US6369756B1 (en) * | 2000-03-28 | 2002-04-09 | Nokia Networks Oy | Method and apparatus for optimizing the usage of an antenna array beamforming technique |
-
2000
- 2000-03-28 US US09/537,049 patent/US6369756B1/en not_active Expired - Lifetime
-
2001
- 2001-03-23 JP JP2001571574A patent/JP2003529276A/en active Pending
- 2001-03-23 KR KR1020027012808A patent/KR100669985B1/en active IP Right Grant
- 2001-03-23 WO PCT/IB2001/000495 patent/WO2001073971A2/en active IP Right Grant
- 2001-03-23 EP EP01919685A patent/EP1277292B1/en not_active Expired - Lifetime
- 2001-03-23 DE DE60130548T patent/DE60130548T2/en not_active Expired - Lifetime
- 2001-03-23 AT AT01919685T patent/ATE373901T1/en not_active IP Right Cessation
- 2001-12-27 US US09/887,700 patent/US6580394B2/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5680142A (en) * | 1995-11-07 | 1997-10-21 | Smith; David Anthony | Communication system and method utilizing an antenna having adaptive characteristics |
US5936569A (en) * | 1997-12-02 | 1999-08-10 | Nokia Telecommunications Oy | Method and arrangement for adjusting antenna pattern |
Non-Patent Citations (1)
Title |
---|
See also references of EP1277292A2 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008077113A1 (en) * | 2006-12-19 | 2008-06-26 | Airgain, Inc. | Optimized directional mimo antenna system |
US8248970B2 (en) | 2006-12-19 | 2012-08-21 | Airgain, Inc. | Optimized directional MIMO antenna system |
EP3487224A4 (en) * | 2016-08-12 | 2019-05-22 | Huawei Technologies Co., Ltd. | Method for switching signal transmission mode, base station and terminal device |
Also Published As
Publication number | Publication date |
---|---|
EP1277292B1 (en) | 2007-09-19 |
KR20030064617A (en) | 2003-08-02 |
EP1277292A2 (en) | 2003-01-22 |
US6369756B1 (en) | 2002-04-09 |
US20020089451A1 (en) | 2002-07-11 |
ATE373901T1 (en) | 2007-10-15 |
DE60130548D1 (en) | 2007-10-31 |
KR100669985B1 (en) | 2007-01-18 |
JP2003529276A (en) | 2003-09-30 |
US6580394B2 (en) | 2003-06-17 |
DE60130548T2 (en) | 2008-01-31 |
WO2001073971A3 (en) | 2002-06-20 |
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