Enhanced uplink rate selection by a communication device during soft handoff
View Patent ↗A method for rate selection by a communication device for enhanced uplink during soft handoff in a wireless communication system includes a first step of receiving information from a scheduler. This information can include one or more of scheduling, a rate limit, a power margin limit, and a persistence. A next step includes determining a data rate for an enhanced uplink during soft handoff using the information. A next step includes transmitting to a serving base station on an enhanced uplink channel at the data rate determined from the determining step.
1. A method for rate selection by a communication device for uplink during soft handoff in a communication system, the method comprising steps of:
receiving a scheduling assignment message including a power margin limit from a scheduler;
determining a data rate for an uplink transmission during soft handoff using the power margin limit, local channel conditions and a buffer occupancy of the communication device; and
transmitting to a serving base station on an uplink channel at the data rate determined from the determining step;
wherein the determining step includes a data rate constraint of
K 2 *P margin — limit /P dpcch *TPC _correction
where P margin — limit is the power margin limit, P dpcch is a power of the downlink physical control channel, and K2 is a scale factor, and TPC_correction dependent upon a power control command history and pilot channel signal strength.
2. A method for rate selection by a communication device for uplink during soft handoff in a communication system, the method comprising steps of:
receiving a scheduling assignment message including a power margin limit from a scheduler;
determining a data rate for an uplink transmission during soft handoff using the power margin limit, local channel conditions and a buffer occupancy of the communication device; and
transmitting to a serving base station on an uplink channel at the data rate determined from the determining step;
wherein the determining step includes a data rate constraint of
R max — effective — SHOtarget *g(imbalance)
where R max — effective — SHOtarget is the maximum effective rate, and g(imbalance) is an imbalance between a transmission gain of the scheduling cell and communication device, divided by a transmission gain between an adjacent cell with next largest or largest transmission gain relative to scheduling cell and the communication device.