Combined open loop/closed loop (CQI-based) uplink transmit power control with interference mitigation for E-UTRA
A combined open loop and closed loop (channel quality indicator (CQI)-based) transmit power control (TPC) scheme with interference mitigation for a long term evolution (LTE) wireless transmit/receive unit (WTRU) is disclosed. The transmit power of the WTRU is derived based on a target signal-to-interference noise ratio (SINR) and a pathloss value. The pathloss value pertains to the downlink signal from a serving evolved Node-B (eNodeB) and includes shadowing. An interference and noise value of the serving eNodeB is included in the transmit power derivation, along with an offset constant value to adjust for downlink (DL) reference signal power and actual transmit power. A weighting factor is also used based on the availability of CQI feedback.
1. A method of performing transmit power control (TPC) of a wireless transmitter/receiver unit (WTRU) comprising:
receiving downlink control information including both uplink scheduling information and TPC information, wherein the uplink scheduling information includes modulation and coding set (MCS) information;
determining a transmit power level for a physical uplink channel, based on at least a measured pathloss, wherein the determined transmit power level is adjusted in response to the TPC information and the MCS information, wherein the determined transmit power level is further based on a weighting factor, α, where α:
has a value from 0 to 1; and
is multiplied to the measured pathloss; and
transmitting on the physical uplink channel based on the scheduling information and the determined transmit power level.
2. A method according to claim 1 , wherein the physical uplink channel is a physical uplink shared channel (PUSCH).
3. A method according to claim 2 , wherein the determined transmit power level is further based on a modulation and coding set (MCS) factor associated with an MCS of the physical uplink shared channel transmission.
4. A method according to claim 1 , wherein the determined transmit power control factor is based at least in part on a closed loop power control factor.
5. A method according to claim 1 , wherein the determined transmit power level is based on a maximum transmit power level.
6. A method according to claim 1 , wherein the physical uplink channel is a physical uplink control channel (PUCCH).
7. A method according to claim 6 , wherein the determined transmit power level is further based on a quality factor associated with channel quality indication (CQI) information of the PUCCH.
8. A wireless transmitter/receiver unit (WTRU) comprising:
a receiver configured to receive downlink control information including both uplink scheduling information and transmit power control (TPC) information, wherein the uplink scheduling information includes modulation and coding set (MCS) information;
a processor configured to determine a transmit power level for a physical uplink channel, based on at least a measured pathloss, wherein the determined transmit power level is adjusted in response to the TPC information, the MCS information and wherein the determined transmit power level is further based on a weighting factor, α, where α:
has a value from 0 to 1; and
is multiplied to the measured pathloss; and
a transmitter operably coupled to the processor, the transmitter configured to transmit on the physical uplink channel based on the scheduling information and the determined transmit power level.
9. A WTRU according to claim 8 , wherein the physical uplink channel is a physical uplink shared channel (PUSCH).
10. A WTRU according to claim 9 , wherein the determined transmit power level is further based on a modulation and coding set (MCS) factor associated with an MCS of the physical uplink shared channel transmission.
11. A WTRU according to claim 8 , wherein the determined transmit power level is based at least in part on a closed loop power control factor.
12. A WTRU according to claim 8 , wherein the determined transmit power level is based on a maximum transmit power level.
13. A WTRU according to claim 8 , wherein the physical uplink channel is a physical uplink control channel (PUCCH) and the determined transmit power level is further based on a quality factor associated with channel quality indication (CQI) information of the PUCCH.