A fast real time link adaptation scheme for wireless communication systems

Abstract

In this paper, a fast real time link adaptation scheme for wireless communication systems is proposed. The proposed scheme is employing multi-stage adaptation controls based on channel state information (CSI). The optimal link adaptation scheme is known to have high complexity to implement, and it shoud be run iteratively to deal with time varying wireless channels in a short time. The proposed method determines the speed of channel variation using CSFs, then it applies the most appropriate link adaptation methodology or algorithm to the current time varying rate of channels. For examples, a simple up/down transmit power adjustment is used for the very fast time varying channel condition. On the other hand, the optimal link adaptation scheme is directly applied in the very slow varying channel state. The proposed multi-stage link adaptation scheme can be easily implemented in real time wirelss communication systems because of its capability of selecting an appropriate real time link adaptation scheme adaptively to each channel variation rate. The design example on the selected platform shows that the proposed scheme is very efficient in real time applications of the link adaptation in wireless communications, while its performance is maintained close to the optimal. © Springer-Verlag Berlin Heidelberg 2007.