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;
the processor configured to determine a plurality of channel quality indicators (CQIs) using measurements of downlink transmissions;
the processor and the receiver configured to receive at least one radio resource control (RRC) message; and
the processor and the transmitter configured to periodically transmit control information in slots based on the received at least one RRC message, wherein the control information includes CQIs, from the plurality of CQIs, for a plurality of cells;
wherein the control information contains CQIs related to a first cell of the plurality of cells and a second cell of the plurality of cells, wherein CQIs are transmitted on the first cell of the plurality of cells at a different frequency than with which CQIs are transmitted on the second cell of the plurality of cells;
wherein, on a condition that a first configured time period associated with the first cell of the plurality of cells expires, for a second time period the control information contains CQIs related to the second cell of the plurality of cells and not the first cell of the plurality of cells.
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 second time period begins after the first configured time period expires.
5. The WTRU of claim 1 , wherein the second time period begins after a layer 2 (L2) message associated with the first cell of the plurality of cells is received.
6. 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 of the plurality of cells and second ACK/NACK information to a second base station associated with the second cell of the plurality of cells.
7. 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 of the plurality of cells.
8. The WTRU of claim 1 , wherein the WTRU is configured to use a same code for transmission of CQIs on the first cell and for transmission of CQIs on the second cell.
9. The WTRU of claim 1 , wherein the CQIs are transmitted on slots which are staggered between the first cell and the second cell.
10. The WTRU of claim 1 , wherein a first slot offset with which CQIs are transmitted on the first cell of the plurality of cells is different than a second slot offset with which CQIs are transmitted on the second cell of the plurality of cells.
11. The WTRU of claim 1 , wherein CQIs are sent on one of the first cell of the plurality of cells or the second cell of the plurality of cells in response to an additional base station being accessible to the WTRU.
12. The WTRU of claim 1 , wherein the WTRU ceases transmission of CQIs on one of the first cell of the plurality of cells or the second cell of the plurality of cells based on a change of a serving base station.
13. The WTRU of claim 1 , wherein the at least one RRC message specifies a CQI transmission frequency.
14. A method performed by a wireless transmit/receive unit (WTRU), the method comprising:
receiving, by the WTRU, at least one radio resource control (RRC) message;
determining, by the WTRU, a plurality of channel quality indicators (CQIs) using measurements of downlink transmissions; and
transmitting, periodically by the WTRU to a network, control information in slots based on the received at least one RRC message, wherein the control information includes CQIs, from the plurality of CQIs, for a plurality of cells;
wherein the control information contains CQIs related to a first cell of the plurality of cells and a second cell of the plurality of cells, wherein CQIs are transmitted on the first cell of the plurality of cells at a different frequency than with which CQIs are transmitted on the second cell of the plurality of cells; and
wherein, on a condition that a first configured time period associated with the first cell of the plurality of cells expires, for a second time period the control information contains CQIs related to the second cell of the plurality of cells and not the first cell of the plurality of cells.
15. The method of claim 14 further comprising switching, by the WTRU, between sending additional control information indicating the plurality of CQIs and control information indicating a single CQI.
16. The method of claim 14 , wherein the plurality of CQIs are associated with different base stations.
17. The method of claim 14 , wherein the downlink transmissions are received using a high speed downlink shared channel (HS-DSCH).
18. The method of claim 14 , wherein the plurality of cells are High-speed Downlink Packet Access (HSDPA) serving cells.
19. The method of claim 14 , wherein the second time period begins after the first configured time period expires.
20. The method of claim 14 , wherein the second time period begins after a layer 2 (L2) message associated with the first cell of the plurality of cells is received.