A proposal for EGPRS radio link control using link adaptation and incremental redundancy

Standardization is currently in progress to specify Enhanced Data rates for GSM Evolution (EDGE). The two components of EDGE, Enhanced Circuit-Switched Data (ECSD) and Enhanced General Packet Radio Service (EGPRS), define enhancements for circuit-mode and packet-mode data, respectively. EGPRS is also intended to provide a high-rate North American digital time division multiple access (TDMA) packet data service. To achieve higher data rates, 8-ary phase shift keying (8-PSK) modulation has been introduced. Enhanced radio link control (RLC) procedures are being defined based on link adaptation and incremental redundancy to achieve superior delay/throughput performance over a wide range of operating conditions. This paper describes a candidate proposal for (RLC) block segmentation for EGPRS that provides combined link adaptation and incremental redundancy; short, fixed-length blocks to achieve lower block error rates; seamless transition between coding schemes without loss in throughput; segmentation to provide a robust Gaussian minimum shift keying (GMSK) fallback mode; and short and extended header formats. We present performance tradeoffs for the proposed scheme. Many of the features of this proposal have been included in the EGPRS specification. We provide a brief description of the block and header formats being standardized.