An Aloha-Based Channel Access Scheme Investigation for Broadband Wireless Networks

• Venue: ISCC '99 Proceedings of the The Fourth IEEE Symposium on Computers and Communications
• Year: 1999

The hybrid Demand assignment TDMA (D-TDMA) protocol has been suggested by many leading researchers as the most suitable MAC protocol for the WATM at the present time. Within the Hybrid D-TDMA protocol architecture, S-Aloha is suggested as the channel access scheme for the remote terminals to signal their connection establishment/reestablishment requests to the base station.In this paper we thoroughly analyze and qualitatively evaluate the performance of the S-Aloha as an Embedded channel access (ES-Aloha) scheme for the hybrid D-TDMA protocol. The performance of the normal S-Aloha is well researched and presented in the literature, however, the ES-Aloha, as part of a hybrid MAC protocol, as presented in this paper, has not been studied yet. In contrast to the normal S-Aloha, the ES-Aloha performance is highly affected by the Connection Admission Control (CAC) procedure, network resources, and traffic parameters. The performance of the ES-Aloha is compared with the normal S-Aloha scheme, as a stand-alone, and some useful results and conclusions are drawn. Based on that, an adaptive ES-Aloha scheme is proposed, which we refer to as Buffered Request Embedded S-Aloha (BES-Aloha), to better utilize the available information at the base station and to improve the performance of the channel access scheme. In addition, Power Control PC "Captured S-Aloha" and Dynamic Boundary DB allocation mechanisms are deployed for qualitatively evaluating their impacts on the channel access level and the overall network performance. Moreover, the effect of CAC in the broadband wireless network performance is discussed.For improving the wireless channel efficiency and increasing the network revenue, an ABR Burst-Based (ABR BB) Bandwidth reservation mode is proposed, and its performance evaluation and impacts on the system behavior is presented and discussed.In this paper we demonstrated that the channel access scheme dictates to a great extent the performance of the Broadband D-TDMA MAC protocol, and consequently, the overall performance of the network. It has impacts on the following issues: QoS levels, as it controls the connection/burst setup and bandwidth reservation, protocol efficiency and reliability, and network complexity.