# US 7,610,025 B2 · Antenna array pattern distortion mitigation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,610,025 B2 - Document ID: US7610025B2 - Status: Granted - Kind: B2 - Application number: 11/182,236 - Filed: 2005-07-15 - Published: 2006-10-05 - Granted: 2009-10-27 - Earliest claimed: 2005-03-29 - Assignees: QUALCOMM Incorporated - Inventors: Ivan Jesus Fernandez-Corbaton; Ahmad Jalali; Ernest T. Ozaki; Harris Smith Simon; Sherman A. Gregory - Web page: https://patentgrep.com/patent/US7610025B2 ## CPC - H01Q 25/00: Antennas or antenna systems providing at least two radiating patterns (arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00) - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract At least one feature provides a way to perform point-to-multipoint transmissions using adaptive or directional antennas while reducing antenna pattern distortion. Generally, rather than transmitting the same waveform to two or more receivers, an information-bearing signal is transformed into different decorrelated waveforms and each decorrelated waveform is transmitted to a different receiver. In one implementation, an information-bearing signal is transformed into two decorrelated signals such that their crosscorrelation, or autocorrelation of the information-bearing signal, is zero or very small. Such decorrelation may be achieved by sending a first signal to a first receiver while sending a second signal, having a radio frequency spectrum that is the spectrally inverted version of the first signal, to a second receiver. In another implementation, a first signal is transmitted to a first receiver and is also transmitted to a second receiver with a time delay. ## Claims ### Claim 1 A method for mitigating antenna array pattern distortions in signals transmitted to different receivers, the method comprising using one or more processors to perform the following computer executable acts: selecting a first signal and a second signal that are decorrelated versions of a third signal; transmitting the first signal to a first receiver; and transmitting the second signal to a second receiver; wherein selecting the first and second signals comprises: selecting first and second codes that are different from each other; applying the first code to the third signal to generate the first signal; and applying the second code to the third signal to generate the second signal. ### Claim 2 The method of 1, wherein selecting the first and second signals comprises: selecting two signals such that their cross-correlation is approximately zero or negligibly small. ### Claim 3 The method of 1, wherein the second code is the spectrum inverted version of the first code. ### Claim 4 The method of 1, wherein the first and second signals are transmitted in different directional beams. ### Claim 5 (depends on 1) The method of claim 1, further comprising: at the first and second receivers, searching for one of either a non-inverted signal or an inverted signal, based on upper layer signaling of a communication system. ### Claim 6 A method for mitigating antenna array pattern distortions in signals transmitted to different receivers, the method comprising using one or more processors to perform the following computer executable acts: selecting a first signal and a second signal that are decorrelated versions of a third signal; transmitting the first signal to a first receiver; and transmitting the second signal to a second receiver; wherein selecting the first and second signals comprises: selecting a first code that is a time-delayed version of a second code; applying the first code to the third signal to generate the first signal; and applying the second code to the third signal to generate the second signal. ### Claim 7 A method for mitigating antenna array pattern distortions in signals transmitted to different receivers, the method comprising using one or more processors to perform the following computer executable acts: selecting a first signal and a second signal that are decorrelated versions of a third signal; transmitting the first signal to a first receiver; and transmitting the second signal to a second receiver; wherein selecting the first and second signals comprises: selecting a first code that is a time-reversed version of a second code; applying the first code to the third signal to generate the first signal; and applying the second code to the third signal to generate the second signal. ### Claim 8 An apparatus for mitigating antenna array pattern distortions in signals transmitted to different receivers, the apparatus comprising: means for generating first and second signals that are decorrelated versions of a third signal; and means for transmitting the first and second signals to different receivers on different beams; wherein the means for generating the first and second signals comprises: means for selecting first and second polynomials that are different from each other; means for applying the first polynomial to the third signal to generate the first signal; and means for applying the second polynomial to the third signal to generate the second signal. ### Claim 9 The apparatus of 8 further comprising: means for selecting the first and second signals such that their cross-correlation is approximately zero or negligibly small. ### Claim 10 The apparatus of 8, wherein the means for transmitting the first and second signals to different receivers on different beams include configurable directional transmission means for transmitting the first and second signals in different directional beams. ### Claim 11 An apparatus for mitigating antenna array pattern distortions in signals transmitted to different receivers, the apparatus comprising: means for generating a first and second signals that are decorrelated versions of a third signal; and means for transmitting the first and second signals to different receivers on different beams: wherein the means for generating the first and second signals comprises: means for selecting a first polynomial that is a time-delayed version of a second polynomial; means for applying the first polynomial to the third signal to generate the first signal; and means for applying the second polynomial to the third signal to generate the second signal. ### Claim 12 An apparatus for mitigating antenna array pattern distortions in signals transmitted to different receivers, the apparatus comprising: means for generating first and second signals that are decorrelated versions of a third signal; and means for transmitting the first and second signals to different receivers on different beams; wherein the means for generating the first and second signals comprises: means for selecting a first polynomial that is a time-reversed version of a second polynomial; means for applying the first polynomial to the third signal to generate the first signal; and means for applying the second polynomial to the third signal to generate the second signal. ### Claim 13 A machine readable medium tangibly embodying instructions executable by a processor for mitigating antenna array pattern distortions in signals transmitted to different receivers, which when executed by a processor, causes the processor to perform operations comprising: generating an information-bearing signal; generating a first signal and a second signal that are decorrelated versions of the information-bearing signal; and transmitting the first signal and second signal to different receivers; wherein generating the first and second signals comprises: selecting a first and second codes that are different from each other; applying the first code to the information-bearing signal to generate the first signal; and applying the second code to the information-bearing signal to generate the second signal. ### Claim 14 The machine readable medium of 13, wherein generating the first and second signals comprises: processing the first and second signals such that their cross-correlation is approximately zero or negligibly small. ### Claim 15 A machine readable medium -tangibly embodying instructions executable by a processor for mitigating antenna array pattern distortions in signals transmitted to different receivers, which when executed by a processor, causes the processor to perform operations comprising: generating an information-bearing signal; generating a first signal and a second signal that are decorrelated versions of the information-bearing signal; and generating the first signal and second signal to different receivers; wherein generating the first and second signals comprises: selecting a first code that is a time-delayed version of a second code; applying the first code to the information-bearing signal to generate the first signal; and applying the second code to the information-bearing signal to generate the second signal. ### Claim 16 A machine readable medium tangibly embodying instructions executable by a processor for mitigating antenna array pattern distortions in signals transmitted to different receivers, which when executed by a processor, causes the processor to perform operations comprising: generating an information-bearing signal; generating a first signal and a second signal that are decorrelated versions of the information-bearing signal; and transmitting the first signal and second signal to different receivers; wherein generating the first and second signals comprises: selecting a first code that is a time-reversed version of a second code; applying the first code to the information-bearing signal to generate the first signal; and applying the second code to the information-bearing signal to generate the second signal. ### Claim 17 A wireless transmitter comprising: a configurable directional antenna; and a processing circuit communicatively coupled to the directional antenna to configure the antenna and process signals transmitted through the directional antenna, the processing circuit configured to generate a first signal and a second signal that are decorrelated versions of a third signal, transmit the first signal to a first receiver, and transmit the second signal to a second receiver; wherein the first and second signals are generated by one of either: selecting a first and second codes that are different from each other, selecting a first code that is a time-delayed version of a second code, or selecting a first code that is a time-reversed version of a second code. ### Claim 18 The transmitter of 17 wherein the first and second signals are such that their cross-correlation is approximately zero or negligibly small. ### Claim 19 The transmitter of 17 further comprising: applying the first code to the third signal to generate the first signal; and applying the second code to the third signal to generate the second signal. ### Claim 20 The transmitter of 17 further comprising: a storage device communicatively coupled to the processing circuit to store values used to configure the directional antenna. ### Claim 21 The transmitter of 20 wherein the transmitter configures the directional antenna to transmit the first signal to the first receiver on a first beam, and transmit the second signal to the second receiver on a second beam. ### Claim 22 The transmitter of 17 wherein the transmitter is mounted on a moving aircraft and the first and second receivers are stationary. ### Claim 23 The transmitter of 17 wherein the transmitter initiates a handoff procedure between the first and second receivers. ### Claim 24 The transmitter of 23 wherein the processing circuit is further configured to transfer communications to the second receiver once a link is established with the second receiver. ### Claim 25 The transmitter of 23 wherein the processing circuit is further configured to terminate communications with the first receiver once a link is established with the second receiver. ### Claim 26 The transmitter of 17 wherein the processing unit is further configured to search for pilot signals from receivers on a plurality of beams. ### Claim 27 The transmitter of 17 farther comprising: a second antenna communicatively coupled to the processing circuit and selectably activated to search for the presence of other receivers. ### Claim 28 A microprocessor comprising: an input interface to receive an information-bearing signal; a circuit configured to generate a first signal and a second signal that are decorrelated versions of the information-bearing signal; and an output interface to send the first signal and second signal to an antenna for transmission; wherein the circuit is further configured to generate the first and second signals by either: selecting a first and second codes that are different from each other, selecting a first code that is a time-delayed version of a second code, or selecting a first code that is a time-reversed version of a second code. ### Claim 29 The microprocessor of 28 wherein the circuit is further configured to switch the antenna from a first direction to a second direction so that the first signal is transmitted in the first direction and the second signal is transmitted in the second direction. ### Claim 30 The microprocessor of 28 wherein the circuit is further configured to apply the first code to the information-bearing signal to generate the first signal; and apply the second code to the information-bearing signal to generate the second signal.