Method and System for Uplink Beamforming Calibration in a Multi-Antenna Wireless Communication System
A wireless transceiver, comprising a transmitter, a receiver and a plurality of antennas, determines transmit phase relationship between at least two of antennas based on radio frequency (RF) signals received via the at least two antennas from one or more antennas of a base station. RF signals are transmitted via the at least two antennas utilizing the determined transmit phase relationship. The receiver is calibrated based on receiver performance determined from the received RF signals for subsequent reception of RF signals. The transmit phase relationship is dynamically adjusted based on the transmit RF measurements and the determined receiver performance. Transmit channel qualities are determined for each transmit antenna based on the transmit RF measurements and the dynamically adjusted transmit phase relationship. Transmit antennas are dynamically selected based on the adjusted transmit phase relationship, the characterized transmit channel qualities and the determined receiver performance for subsequent transmission to the base station.
1 . A method, comprising:
in a wireless transceiver:
determining a transmit path phase difference between a first antenna and a second antenna in the wireless transceiver;
determining a receive path phase difference between the first and second antennas:
determining a wireless channel phase difference associated with the first and second antennas based on downlink radio frequency signals received by the first and second antennas from a base station antenna of a base station; and
transmitting uplink radio frequency signals via the first and second antennas to the base station based on a composite phase difference equal to a sum of the trans it path phase difference, the receive path phase difference and the wireless channel phase difference.
2 . The method according to claim 1 , wherein determining the transmit path phase difference includes using a calibration signal.
3 . The method according to claim 1 , wherein determining the receive path phase difference includes using a calibration signal.
4 . The method according to claim 1 , wherein determining the wireless channel phase difference includes using a pilot signal,
5 . The method according to claim 1 , wherein determining the transmit phase difference includes using a directional coupler.
6 . The method according to claim 1 , wherein determining the receive phase difference includes using a directional coupler.
7 . The method according to claim 1 , wherein determining the transmit path phase difference and determining the receive path phase difference are done on a frequency selective basis or on a non-frequency selective basis.
8 . The method according to claim 1 , wherein transmitting uplink radio frequency signals includes separately amplifying each of the uplink radio frequency signals.
9 . The method according to claim 1 , wherein the first and second antennas are adaptively selected from a plurality of wireless transceiver antennas based on characterized channel qualities associated with the plurality of wireless transceiver antennas.
10 . The method according to claim 1 , further comprising:
selecting power levels of the uplink radio frequency signals based on the determined transmit path phase difference, the determined receive path phase difference and the determined wireless channel phase difference.
11 . A wireless transceiver, comprising:
one or more circuits configured to:
determine a transmit path phase difference between a first antenna and a second antenna in the wireless transceiver;
determine a receive path phase difference between the first and second antennas;
determine a wireless channel phase difference associated with the first and second antennas based on downlink radio frequency signals received by the first and second antennas from a base station antenna of a base station; and
transmit uplink radio frequency signals via the first and second antennas to the base station based on a composite phase difference equal to a sum of the transmit path phase difference, the receive path phase difference and the wireless channel phase difference.
12 . The wireless transceiver according to claim 11 , wherein the one or more circuits are further configured to determine the transmit path phase difference using a calibration signal.
13 . The wireless transceiver according to claim 11 , wherein the one or more circuits are further configured to determine the receive path phase difference using a calibration signal.
14 . The wireless transceiver according to claim 11 , wherein the one or more circuits are further configured to determine the wireless channel phase difference using a pilot signal.
15 . The wireless transceiver according to claim 11 , wherein the one or more circuits are further configured to determine the transmit phase difference using a directional coupler.
16 . The wireless transceiver according to claim 11 , wherein the one or more circuits are further configured to determine the receive phase difference using a directional coupler.
17 . The wireless transceiver according to claim 11 , wherein the one or more circuits are further configured to determine the transmit path phase difference and determine the receive path phase difference on a frequency selective basis or on a non-frequency selective basis.
18 . The wireless transceiver according to claim 11 , wherein the one or more circuits are further configured to separately amplifying each of the uplink radio frequency signals.
19 . The wireless transceiver according to claim 11 , wherein the one or more circuits are further configured to adaptively select the first and second antennas from a plurality of wireless transceiver antennas based on characterized channel qualities associated with the plurality of wireless transceiver antennas.
20 . The wireless transceiver according to claim 11 , wherein the one or more circuits are further configured to:
select power levels of the uplink radio frequency signals based on the determined transmit path phase difference, the determined receive path phase difference and the determined wireless channel phase difference.