An adaptive radio link protocol with enhanced data rates for GSM evolution

In this article we address the problem of link adaptation in a wireless data system. Link adaptation is necessary in order to match the data rate to time-varying channel and interference conditions. We present a robust radio link protocol (RLP) based on the concept of incremental redundancy (IR). Here, redundant data, for the purpose of error correction, is transmitted only when previously transmitted packets of information are received and acknowledged to be in error. The redundant packet is combined with the previously received (errored) information packets in order to facilitate error correction decoding.