Design and Development of a Hybrid TDMA/CDMA MAC Protocol for Multimedia Wireless Networks

A wireless local area network (WLAN) provides high bandwidth to users in a limited geographical area. This network faces certain challenges and constraints that are not imposed on their wired counterparts. They are: frequency allocation, interference and reliability, security, power consumption, human safety, mobility, connection to wired LAN, service area, handoff and roaming, dynamic configuration and the throughput. But the wireless medium relies heavily on the features of MAC protocol and the MAC protocol is the core of medium access control for WLANs. The available MAC protocols all have their own merits and demerits. In our research works, we propose a hybrid MAC protocol for WLAN. In the design, we have combined the merits of the TDMA and CDMA systems to improve the throughput of the WLAN in a picocellular environment. We have used the reservation and polling methods of MAC protocols to handle both the low and high data traffics of the mobile users. We have strictly followed the standards specified by IEEE 802.11 for WLANs to implement the designed MAC protocol. We have simulated the hybrid TDMA/CDMA based MAC protocols combined with RAP (Randomly Addressed Polling) for Wireless Local Area Networks. We have developed a closed form mathematical expressions analytically for this protocol. We have also studied the power control aspects in this environment and we derived a closed form mathematical expressions analytically for this power control technique. This hybrid protocol is capable of integrating different types of traffic (like CBR, VBR and ABR services) and compiles with the requirements of next-generation systems. The lower traffic arrival is dealt with the Random Access and the higher traffic arrival