Communication of control information in wireless communication systems
View Patent ↗A wireless system has a high rate data channel for time multiplexed communications to multiple mobile stations (MSs). Control channels include a forward link common power control channel and reverse link feedback channels for pilot, forward channel quality, and data acknowledgements from each MS. An MS can have an active state for data communications, for which these control channels are used at the full (time slot) rate, or a control hold state, in which acknowledgements are not needed and the others of these control channels can be shared among a plurality of MSs in the control hold state and each using a reduced rate such as ½, ¼, or ⅛ of the full rate. The arrangement can support an increased number of active MSs, facilitating an increased total throughput on the high rate data channel, without increasing system resources for the control channels.
1. A method of communicating control information in a wireless communications system, comprising the steps of:
in a first state of a terminal for traffic communication with the terminal, communicating control information with the terminal at a first rate;
in a second state of the terminal, communicating at least some of said control information at a second rate which is less than the first rate; and
sharing a communication channel for the control information at the second rate for communicating control information among a plurality of terminals in the second state,
wherein the control information is communicated in time slots of at least one communication channel of the system, wherein control information at the first rate is communicated with a terminal in the first state in each time slot on the communication channel, and wherein control information at the second rate is communicated with a terminal in the second state in only one of every N time slots on the communication channel, where N is an integer greater than one.
2. A method as claimed in claim 1 wherein the control information communicated at the second rate in the second state of the terminal comprises power control information for the terminal.
3. A method as claimed in claim 1 wherein the control information communicated at the second rate in the second state of the terminal comprises a pilot from the terminal.
4. A method as claimed in claim 1 wherein the control information communicated at the second rate in the second state of the terminal comprises a channel quality indication from the terminal.
5. A method as claimed in claim 1 wherein the control information communicated at the second rate in the second state of the terminal comprises a pilot and a channel quality indication from the terminal.
6. A method as claimed in claim 1 wherein the second rate is a sub-multiple of the first rate.
7. A method as claimed in claim 1 and including the step of switching between the first and second states of the terminal in dependence upon whether or not a data buffer for traffic communication with the terminal is empty.