Backhaul radio with adaptive beamforming and sample alignment

• US 10,716,111 B2
• Filed: 11/28/2017
• Issued: 07/14/2020
• Est. Priority Date: 08/17/2011
• Status: Active Grant

• Current Assignee: COMS IP Holdings LLC
• Original Assignee: Skyline Partners Technology, LLC (COMSovereign Holding Corp.)
• Inventors: Ishiguro, Arthur, Raja, Adnan, Varadarajan, Badri, Negus, Kevin J.
• Primary Examiner(s): Moore, Jr., Michael J
• Assistant Examiner(s): Sharma, Gautam
• Application Number:
  US15/825,032
• Publication Number:
  US 20180092099A1
• Time in Patent Office: 959 Days
• Field of Search: None
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 21/205 providing an omnidirectional coverage turnstile aerials H01Q21/26
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: 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
• CPC Class Codes: H01Q 25/005 providing two patterns of opposite direction; back to back antennas H01Q25/004 takes precedence
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 5/50 Feeding or matching arrangements for broad-band or multi-band operation
• CPC Class Codes: H04B 2001/0408 with power amplifiers
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04L 1/00 Arrangements for detecting or preventing errors in the information received correcting synchronisation H04L7/00
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1671 the supervisory signal being transmitted together with control information
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 : using sounding signals
• CPC Class Codes: H04L 25/03019 : adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 27/0008 : arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/01 : Equalisers baseband equalizers at the transmitter end H04L25/03343; in analogue transmission systems H04B3/04, H04B7/005
• CPC Class Codes: H04L 27/2636 : with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 27/2678 : using cyclostationarities, e.g. cyclic prefix or postfix
• CPC Class Codes: H04L 5/0007 : the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0023 : Time-frequency-space
• CPC Class Codes: H04L 5/0028 : Variable division signaling therefor H04L5/0092
• CPC Class Codes: H04L 5/0048 : Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/006 : Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/14 : Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/143 : for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04W 24/02 : Arrangements for optimising operational condition
• CPC Class Codes: H04W 52/52 : using AGC [Automatic Gain Control] circuits or amplifiers
• CPC Class Codes: H04W 72/04 : Wireless resource allocation
• CPC Class Codes: H04W 72/0453 : Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 76/27 : Transitions between radio resource control [RRC] states
• CPC Class Codes: H04W 84/12 : WLAN [Wireless Local Area Networks]

Abstract

A backhaul radio is disclosed that operates in multipath propagation environments such as obstructed LOS conditions with uncoordinated interference sources in the same operating band. Such a backhaul radio may use adaptive beamforming and sample alignment at the transmitter to enhance the link performance. Such backhaul radios may communicate with each other to compute and apply optimal beamforming parameters for a particular propagation environment through a closed-loop feedback mechanism.

Claims

1. A backhaul radio comprising:

a plurality of receive radio frequency (RF) chains, wherein each receive RF chain is capable of converting from one of a plurality of receive RF signals to a respective one of a plurality of receive chain output signals;

a plurality of directive gain antenna elements; and

a processor at the receiver to compute and feedback the phase and sample timing offset (STO) for optimal beamforming,

wherein the processor is further configured to calculate a plurality of relative STOs and a plurality of relative phase offsets and average and quantize the plurality of relative STOS and the plurality of relative phase offsets to determine the feedback.

2. The backhaul radio of claim 1, wherein the processor is further configured to compute relative STOs and relative phase offsets.

3. The backhaul radio of claim 1, wherein the processor is further configured to receive channel matrix estimates.

4. The backhaul radio of claim 1, wherein the feedback comprises an adjustment of both the phase and STO.

5. The backhaul radio of claim 1, wherein the processor is further configured to perform a channel estimation using a received sounding preamble.

6. The backhaul radio of claim 5, wherein the channel estimation is performed by correlating a received signal with the received sounding preamble.

7. The backhaul radio of claim 1, wherein the processor computes the STO for each element in a channel.

8. The backhaul radio of claim 1, wherein the phase is computed after the STO is computed.

9. The backhaul radio of claim 1, wherein the STO feedback is performed before the phase feedback.

10. A fixed wireless access point comprising:

a plurality of receive radio frequency (RF) chains, wherein each receive RF chain is capable of converting from one of a plurality of receive RF signals to a respective one of a plurality of receive chain output signals;

a plurality of directive gain antenna elements; and

a processor at the receiver to compute and feedback the phase and sample timing offset (STO) for optimal beamforming,

wherein the processor is further configured to calculate a plurality of relative STOs and a plurality of relative phase offsets and average and quantize the plurality of relative STOS and the plurality of relative phase offsets to determine the feedback.

11. The fixed wireless access point of claim 10, wherein the processor is further configured to compute relative STOs and relative phase offsets.

12. The fixed wireless access point of claim 10, wherein the processor is further configured to receive channel matrix estimates.

13. The fixed wireless access point of claim 10, wherein the feedback comprises an adjustment of both the phase and STO.

14. The fixed wireless access point of claim 10, wherein the processor is further configured to perform a channel estimation using a received sounding preamble.

15. The fixed wireless access point of claim 14, wherein the channel estimation is performed by correlating a received signal with the received sounding preamble.

16. The fixed wireless access point of claim 10, wherein the processor computes the STO for each element in a channel.

17. The fixed wireless access point of claim 10, wherein the phase is computed after the STO is computed.

18. The fixed wireless access point of claim 10, wherein the STO feedback is performed before the phase feedback.