The General Packet Radio Service (GPRS) was introduced by ETSI to meet the ever-increasing demand for wireless data over the GSM radio interface. Enhanced GPRS (EGPRS Phase 1) was later introduced in order to increase the spectrum efficiency and data throughput by using 8-PSK modulation and link adaptation techniques. While (E)GPRS uses packet-switched technology to efficiently transmit best-effort data, real-time services (e.g. voice) are currently supported only via circuit-switched systems. This service separation reduces the potential spectrum efficiency gain resulting from multiplexing different services on the same radio channel. This paper describes the key new concepts needed to support statistical multiplexing of different radio access bearer classes over the GSM/EDGE radio access network (GERAN) air interface. The focus is on the definition of new traffic and control channels to support statistical multiplexing of speech, real-time data, and non-real-time data, and the corresponding new MAC procedures that are needed to guarantee quality of service (QoS).

The cellular radio link is characterized by deep fades leading to long error bursts (lasting hundreds of milliseconds). Data transmission over such links results in large packet error rates (in the range 10/sup -3/ to 10/sup -1/). We have designed a radio link protocol (RLP) to achieve high throughput on such links. The RLP is based on frequent, complete or partial feedback of the receiver state. Performance results for the US digital cellular TDMA standard show that the scheme can provide the equivalent of 9.6 kb/s service per full-rate TDMA channel above a carrier to interference ratio of 18 dB.>