Systems and methods for providing a reduced power amplifier transmission mode
A user equipment (UE) that supports multiple antenna transmission via multiple power amplifiers may operate in a reduced power amplifier (PA) mode. When operating in the reduced PA mode, a subset of the UE's power amplifiers are used to transmit uplink signals. A UE may send a preference signal to an e-Node B to request that the UE operate in the reduced PA mode.
1. A user equipment (UE), comprising:
multiple antennas transmitting and receiving signals, wherein:
the UE supports at least a one antenna mode and a closed loop single-user multiple-input multiple-output (SU-MIMO) mode as uplink transmission modes;
a subset of the multiple antennas are used to transmit uplink signals in the one antenna mode; and
said uplink transmission modes are configured via Radio Resource Control (RRC) signaling.
2. The UE of claim 1 , wherein said one antenna mode is an antenna selection mode.
3. The UE of claim 1 , comprising a transmitter to transmit sounding reference signals.
4. The UE of claim 1 , wherein the UE sends a preference signal to an e-Node B (eNB), wherein the preference signal comprises a request for the UE to operate in the one antenna mode.
5. The UE of claim 4 , wherein the preference signal is sent via Media Access Control (MAC) control signaling.
6. The UE of claim 4 , wherein the preference signal is sent via Radio Resource Control (RRC) connection re-establishment signaling.
7. The UE of claim 4 , wherein the preference signal is sent via UE capability transfer signaling.
8. The UE of claim 4 , wherein the preference signal is sent via a measurement report.
9. The UE of claim 4 , wherein the preference signal is sent via Non-Access Stratum (NAS) control signaling.
10. The UE of claim 4 , wherein the preference signal comprises at least one of UE type, battery status, and application type.
11. The UE of claim 1 , wherein the UE sends capability information to an e-Node B (eNB) via UE capability transfer signaling.
12. The UE of claim 1 , wherein the UE sends capability information to an e-Node B (eNB).
13. The UE of claim 1 , wherein the UE creates a preference signal based on evaluating one antenna mode criteria.
14. The UE of claim 13 , wherein the one antenna mode criteria comprises pathloss information.
15. The UE of claim 13 , wherein the one antenna mode criteria comprises battery status.
16. The UE of claim 13 , wherein the one antenna mode criteria comprises an indicator of an E911 call.
17. A method for uplink transmission, wherein:
a user equipment (UE) supports at least a one antenna mode or a closed loop single-user multiple-input multiple-output (SU-MIMO) mode as an uplink transmission mode;
a subset of the multiple antennas are used to transmit uplink signals in the one antenna mode; and
the uplink transmission mode is configured via Radio Resource Control (RRC) signaling.
18. The method of claim 17 , further comprising transmitting sounding reference signals.
19. An enhanced Node B (eNB), wherein:
the eNB configures a user equipment (UE) to operate in at least a one antenna mode or a closed loop single-user multiple-input multiple-output (SU-MIMO) mode as an uplink transmission mode;
a subset of the UE's multiple antennas are used to transmit uplink signals in the one antenna mode; and
the eNB configures the UE to operate in the uplink transmission mode via Radio Resource Control (RRC) signaling.
20. The eNB of claim 19 , wherein the eNB also measures channel conditions.