Method and apparatus for rate adaptation in a wireless communication system

摘要

A method for selection of a particular modulation coding selection (MCS) from a plurality of available MCS selects a particular MCS after obtaining SNR_d, SNR_high, SNR_low, and if SNR_d>SNR_high, selecting the highest available MCS, and if SNR_dSNR_d>SNR_low, selecting MCS based on computing the function/table for each MCS according to the formula:
f(MCS)=(1−PER(length_packet,MCS,SNR_d))/length_packet(packet_size,MCS),
and thereafter selecting the MCS that maximizes the f(MCS) function. Further the neighboring MCS values are characterized for throughput in a throughput characterization step, and compared in throughput to the above determined throughput. In an embodiment of the invention, SNR_high, SNR_low are found by finding the SNR that satisfies:
PER(length_packet,MCS_lowest,SNR_low)=PER_threshPER(length_packet,MCS_highest,SNR_high)=PER_threshWhere PER_thresh is a design parameter, and MCS_lowest is the lowest MCS and MCS_highest is the highest available MCS.

主权项

1. A method for the selection of a particular Modulation and Coding Selection (MCS) from a plurality of available MCS in a wireless communications system, the method having the steps:
obtaining a derived signal to noise ratio (SNR_d); establishing threshold values SNR_high, SNR_low; if SNR_d>SNR_high, selecting the highest MCS; if SNR_dSNR_d>SNR_low, selecting MCS based on: obtaining a table of the product of f(MCS) and f_m corresponding to each MCS, where f(MCS) is an estimate of throughput in the absence of collisions or interference, and f_m is a correction factor for the effects of collisions or interference; selecting the MCS that maximizes said product of f(MCS) and f_m; said plurality of MCS including at least a modulation type and a coding rate; and where said method steps are repeated when a change in SNR_d of more than 2 dB since a previous transmission occurs.