Rate adaptation in a wireless communication system
View Patent ↗Disclosed is a method of data rate adaptation based on channel conditions. Data is initially transmitted at a first data rate based on a measured first channel condition and subsequently re-transmitted at a second data rate based on a measured second channel condition, wherein the first channel condition is measured prior in time to the second channel condition.
1. A method of transmitting data comprising the steps of:
receiving a plurality of rate indication messages indicating data rates for a plurality of receivers;
selecting a first receiver from the plurality of receivers to which to transmit data using the received plurality of rate indication messages, wherein the selected first receiver is associated with a rate indication message indicating a highest data rate;
determining a first data rate based on a measured first channel condition at the first receiver to which data transmission is intended;
performing a first data transmission at the first data rate;
receiving the rate indication message including a data rate based on a channel condition measurement at the first receiver;
determining a second data rate based on the received rate indication message; and
performing a second data transmission of the data at the second data rate, wherein the second data transmission is a re-transmission of the first data transmission.
2. The method of claim 1 , wherein the first and second data transmissions are identical.
3. The method of claim 1 , wherein the first data transmission may be soft combined with the second data transmission.
4. The method of claim 1 , wherein the first data rate is a higher data rate than a data rate indicated in a received rate indication message.
5. The method of claim 1 , wherein the second data rate is a higher data rate than a data rate indicated in a received rate indication message.
6. A method of receiving a data transmission comprising the steps of:
transmitting at a plurality of receivers a plurality of rate indication messages indicating data rates for the plurality of receivers;
receiving at a first receiver a first data transmission at a first data rate, wherein the first data rate is determined using a measured first channel condition, and wherein the first receiver is a receiver selected from the plurality of receivers using the plurality of rate indication messages and the first receiver is associated with a rate indication message indicating a highest data rate;
transmitting the rate indication message if the first data transmission was not successfully received at the first receiver, wherein the rate indication message includes a data rate based on a channel condition measurement at the first receiver; and
receiving a second data transmission at a second data rate, wherein the second data rate is based on the rate indication message.
7. The method of claim 6 comprising the additional step of: storing the received first data transmission if the first data transmission was not successfully received at the first receiver.
8. The method of claim 7 comprising the additional step of: soft combining the stored received first data transmission with the received second data transmission.