A state-machine based design of adaptive wireless MAC layer

A large number of non-converging 2.5G and 3G wireless standards have emerged, over the past, such as, GSM/GPRS, EDGE, IS-95, IxRTT, IxEV -DO, IS-54, IS-136, and IMT2000/UMTS etc. In parallel, unlicensed broadband wireless networks such as IEEE 802.11 and HIPELAN/2 are also spawning across the world. The failure to agree, worldwide, on a unique radio access mode, for economic and political reasons, is forcing the telecommunications community to explore reconfigurable user terminals. Such a reconfigurable radio system will allow the user to roam across geographic areas offering radio access connections using differing standards. To date research into reconfigurable MSs or handsets, also known as SDRs, has predominantly focused on converting physical layer processing into a modularized programmable environment. Although necessary, this only represents a fraction of the overall support and technology required to realize the potential of the concept. Reconfigurability of the higher layers of the protocol stacks is equally important. This paper proposes a software configurable wireless MAC layer design based on the state machine approach. The design exploits the existence of common characteristics in different wireless protocols such as slotted Aloha, p-persistent CSMA, GPRS RLC/MAC protocol and 802.11 MAC protocol. The generic MAC layer design can be re-configured by the software to adapt to a specific wireless MAC layer and be a basis for SDR (software defined radio) mobile station. A methodology for configuring the MAC layer design is also introduced.