Determining and sending channel quality indicators (CQIS) for different cells
A wireless transmit/receive unit (WTRU) may periodically transmit control information in slots. The control information may include channel quality indicators (CQIs) for a plurality of cells. In response to expiration of a timer for a first cell of the plurality of cells or in response to a received layer 2 (L2) message associated with the first cell, the transmission of the control information including the CQIs may be ceased for the first cell and the periodic transmission of the control information may continue for a second cell of the plurality of cells.
1. A wireless transmit/receive unit (WTRU) comprising:
a transmitter;
a receiver; and
a processor configured to determine a plurality of channel quality indicators (CQIs) from measurements of downlink transmissions of a plurality of cells;
the processor and the transmitter configured to send a measurement report including one or more of the plurality of CQIs in a slot of an uplink channel associated with a first cell;
the processor and the receiver configured to receive an update message indicating a serving cell change, the update message including identification of a second cell as a handover target, the update message further including a RRC update message that specifies a CQI transmission frequency;
the processor and the transmitter configured to periodically transmit control information comprising CQIs relating to the first cell and CQIs relating to the second cell, wherein CQIs relating to the first cell are transmitted at a frequency according to a first CQI configuration and CQIs relating to the second cell are transmitted at a frequency according to a second CQI configuration;
wherein, upon indication of successful handover, the control information contains CQIs relating to the second cell and not the first cell.
2. The WTRU of claim 1 , wherein the processor and the transmitter are further configured to switch between sending additional control information indicating the plurality of CQIs and control information indicating a single CQI.
3. The WTRU of claim 1 , wherein the plurality of CQIs are associated with different base stations.
4. The WTRU of claim 1 , wherein the WTRU is configured to send first acknowledgement / negative acknowledgement (ACK/NACK) information to a first base station associated with the first cell and second ACK/NACK information to a second base station associated with the second cell.
5. The WTRU of claim 1 , wherein the WTRU is configured to measure a first downlink reference channel of a first base station of the first cell and measure a second downlink reference signal of a second base station associated with the second cell.
6. The WTRU of claim 1 , wherein the measurement report is sent to the first cell in slots of a physical control channel.
7. The WTRU of claim 1 , wherein the receiver and processor are further configured to receive data from the first cell over a downlink shared channel.
8. The WTRU of claim 7 , wherein the receiver and processor are further configured to receive data from the second cell over a new downlink shared channel after handover.
9. The WTRU of claim 1 , wherein a first slot offset with which CQIs are transmitted on the first cell is different than a second slot offset with which CQIs are transmitted on the second cell.
10. The WTRU of claim 1 , wherein CQIs are sent on one of the first cell or the second cell in response to an additional base station being accessible to the WTRU.
11. The WTRU of claim 1 , wherein the WTRU ceases all transmissions to the first cell or the second cell based on whether the change of a serving station is successful.
12. A method performed by a wireless transmit/receive unit (WTRU), the method comprising the WTRU:
determining a plurality of channel quality indicators (CQIs) based on measurements of downlink transmissions for a plurality of cells;
transmitting a measurement report including one or more of the plurality of CQIs in a slot of an uplink channel associated with a first cell;
receiving a radio resource control (RRC) update message indicating a serving cell change, the RRC update message including identification of a second cell as a handover target, wherein the RRC update message specifies a CQI transmission frequency;
transmitting control information comprising CQIs relating to the first cell and CQIs relating to the second cell, wherein CQIs relating to the first cell are transmitted at a frequency according to a first CQI configuration and CQIs relating to the second cell are transmitted at a frequency according to a second CQI configuration;
wherein, upon indication of successful handover, transmitting updated control information containing CQIs relating to the second cell and not the first cell.
13. The method of claim 12 further comprising switching between sending additional control information indicating the plurality of CQIs and additional control information indicating a single CQI.
14. The method of claim 12 , wherein the plurality of CQIs are associated with different base stations.
15. The method of claim 12 , further comprising:
ceasing all transmissions to one of the first cell or the second cell based on whether the change of a serving station is successful.
16. The method of claim 12 , further comprising:
receiving data from the first cell over a downlink shared channel.
17. The method of claim 16 , further comprising:
receiving data from the second cell over a new downlink shared channel after handover.