Controlling allocation of a portion of a shared channel to use for control information
To control allocation of a portion of a shared channel to use for control information, a base station determines an amount of resource elements of the shared channel to use for the control information in place of traffic data. The base station sends, to a mobile station, an indication relating to an offset parameter, where the indication is provided to allow the mobile station to compute a value for the offset parameter such that the mobile station can determine the amount of the resource elements of the shared channel to allocate for the control information.
1. A method of controlling allocation of a portion of a shared channel to use for control information, comprising:
determining, by a base station, an amount of resource elements of the shared channel to allocate for the control information in place of traffic data; and
sending, by the base station, to a mobile station an indication relating to an offset parameter for controlling allocation of the amount of resource elements of the shared channel for the control information, the indication being selected by the base station as a function of block error rates of data and control information and provided to allow the mobile station to compute a value for the offset parameter, and the indication reflecting an adjustment to be made with respect to a reference value of the offset parameter.
2. The method of claim 1 , wherein determining the amount of the resource elements of the shared channel comprises determining the amount of the resource elements of an uplink shared traffic channel.
3. The method of claim 2 , wherein determining the amount of the resource elements of the shared channel comprises determining a number of coded symbols of the uplink shared traffic channel.
4. The method of claim 1 , wherein sending the indication comprises sending a representation of an absolute adjustment value for adjusting the reference value.
5. The method of claim 4 , wherein sending the representation comprises sending an index value that maps to one of plural absolute adjustment values in a table.
6. The method of claim 1 , further comprising:
sending, by the base station, an indication of the reference value of the offset parameter to the mobile station.
7. The method of claim 6 , wherein sending the indication of the reference value comprises sending an index that corresponds to the reference value.
8. The method of claim 7 , wherein the index maps to one of plural reference values stored at the base station.
9. The method of claim 8 , further comprising storing a data structure mapping plural index values to respective reference values.
10. The method of claim 9 , further comprising re-configuring the mapping between the index values and the respective reference values.
11. The method of claim 6 , wherein sending the indication of the reference value comprises sending an indication of a nominal value.
12. The method of claim 6 , further comprising:
determining that a condition associated with communicating the control information has changed; and
in response to determining the changed condition, sending another indication of a different reference value of the offset parameter to the mobile station.
13. The method of claim 12 , wherein determining that the condition has changed comprises determining that one or more of the following has changed:
a block error rate,
a wireless channel characteristic, and
a payload size of the control information.
14. The method of claim 1 , wherein sending the indication relating to the offset parameter comprises sending the indication using one of RRC (Radio Resource Control) signaling and physical control signaling.
15. The method of claim 1 , further comprising:
detecting, by the base station, that the allocated resource elements for the control information is non-optimal; and
in response to the detecting, sending, by the base station, a resource allocation message containing one or more parameters to the mobile station to cause the mobile station to change allocation of resource elements to the control information in the shared channel.
16. A base station comprising:
an interface configured to communicate wirelessly with a mobile station; and
a processor in communication with the interface and configured to:
determine an amount of resource elements of a shared channel to allocate for control information in place of traffic data; and
send to a mobile station an indication relating to an offset parameter, the indication being selected by the base station as a function of block error rates of data and control information and provided to allow the mobile station to compute a value for the offset parameter to control allocation of resource elements of the shared channel for the control information, and the indication reflecting an adjustment to be made with respect to a reference value of the offset parameter.
17. The base station of claim 16 , wherein the control information is selected from the group consisting of ACK/NACK information, a channel quality indicator (CQI), a precoding matrix index (PMI), and a rank indicator.
18. The base station of claim 16 , wherein the processor is further configured to send another indication relating to the reference value of the offset parameter to the mobile station.