RLC/MAC design alternatives for supporting integrated services over EGPRS

摘要

The Enhanced General Packet Radio Services is one of the proposals submitted to the IMT-2000 initiative of the ITU for third-generation wireless services. EGPRS is also the evolutionary path chosen by the Universal Wireless Communications Consortium, leading toward the convergence of GSM and IS-136 standards for their next-generation wireless systems. We discuss the feasibility of supporting integrated services, such as packet voice, Web browsing, and best-effort data, using EGPRS. We first describe the relevant capabilities offered by the currently proposed standard, and then outline additional capabilities at the radio link control/medium access control layer that are necessary to support integrated services in a spectrally efficient manner. In summary, these needed capabilities are: fast uplink access during an ongoing session; fast resource assignment for both uplink and downlink; and the ability to differentiate services at the base station subsystem. To realize these capabilities, we propose enhancements to the RLC/MAC layer. These enhancements include a new set of packet control channels (namely, a fast packet access channel in the uplink, and a fast packet access grant channel and a fast packet polling channel in the downlink); uplink access protocols that utilize these control channels; and a modified fast uplink access channel structure. These changes would enable EGPRS to offer a wide range of services through a single packet-based network. Similar ideas are also applicable to other third-generation systems.