Wireless multiple access protocols for personal communication systems.

摘要

Personal Communication Systems (PCS) has became a telecommunication industry buzzword in the recent years. The ultimate goal of PCS is to provide an integrated environment so that both conventional voice of cellular systems and advanced broadband network services can be seamlessly extended to mobile users. Fueled by PCS, it can be expected that the demands to access the wireless bandwidth will surge rapidly. Hence, the design of wireless medium access control (MAC) protocols that can effectively manage the sharing of the bandwidth is crucial to the success of PCS.; In this dissertation, several MAC protocols that extend Time Division Multiple Access (TDMA) with the random access technique are proposed. First, two dynamic contention strategies for enhancing the popular packet reservation multiple access (PRMA) protocol are proposed. Under an environment where the number of voice contending terminals can be known, the two strategies can support more number of simultaneous voice connections than that of the PRMA. Second, an adaptive protocol is proposed for voice-only environment. In contrast to the dynamic strategies, this protocol estimates the number of contending terminals. Our simulation studies show that the performance can achieve that of the ideal centralized scheme when terminals are equipped with slow speech activities detectors. Third, a mini-packet reservation (MPRMA) multiple access protocol is proposed to achieve better voice and data integration. This protocol uses smaller reservation packets for contention and continuation flags for extending reservation. As a result, contending slots are increased and reservation for both voice and data users can be extended without going back to the contention mode. Finally, a multimedia multiple access protocol is proposed to support variable bit rate (VBR), constant bit rate (CBR) and arbitrary bit rate (ABR) traffic. In this protocol, a TDMA frame is divided into three portions: setup, request and data slots. The protocol, first, uses setup slots to contend for admission, then, uses assigned request slots of CBR and VBR connections to send additional request packets. Data slots will be assigned to the three types of users according the requests.