Method and apparatus for adjusting channel quality indicator feedback period to increase uplink capacity
A method and apparatus for adjusting a channel quality indicator (CQI) feedback period to increase uplink capacity in a wireless communication system are disclosed. The uplink capacity is increased by reducing the uplink interference caused by CQI transmissions. A wireless transmit/receive unit (WTRU) monitors a status of downlink transmissions to the WTRU and sets the CQI feedback period based on the status of the downlink transmissions to the WTRU. A base station monitors uplink and downlink transmission needs. The base station determines the CQI feedback period of at least one WTRU based on the uplink and downlink transmission needs and sends a command to the WTRU to change the CQI feedback period of the WTRU.
1. A method for adjusting channel quality indicator (CQI) feedback, the method comprising:
receiving, by a wireless transmit/receive unit (WTRU), a radio resource control (RRC) message including CQI configuration information; wherein the CQI configuration information indicates a number of transmission time intervals (TTIs) between CQI transmissions;
transmitting CQI information in TTIs in response to the CQI configuration information;
monitoring, by the WTRU, a physical layer downlink control channel;
in response to information on the physical layer downlink control channel indicating a CQI command and including a cyclic redundancy check (CRC) masked with a WTRU identity associated with the WTRU, transmitting CQI information in a TTI in response to the CQI command received on the physical layer downlink control channel instead of the CQI configuration information received in the RRC message.
2. The method of claim 1 wherein the information on the physical layer downlink control channel includes a single bit indicating the CQI command.
3. A wireless transmit/receive unit (WTRU) comprising:
at least one component configured to receive a radio resource control (RRC) message including channel quality indicator (CQI) configuration information; wherein the CQI configuration information indicates a number of transmission time intervals (TTIs) between CQI transmissions;
the at least one component further configured to transmit CQI information in TTIs in response to the CQI configuration information;
the at least one component further configured to monitor a physical layer downlink control channel;
the at least one component further configured in response to the physical layer downlink control channel indicating a CQI command and including a cyclic redundancy check (CRC) masked with a WTRU identity associated with the WTRU, to transmit CQI information in a TTI in response to the CQI command received on the physical layer downlink control channel instead of the CQI configuration information received in the RRC message.
4. The WTRU of claim 3 wherein information on the physical layer downlink control channel includes a single bit indicating the CQI command.