In this research, we have identified the fundamental drawbacks that prohibit the network to utilize the available resources efficiently. We have shown that the medium access control protocol overhead and collisions in contention control messages play a significant role in its performance issues, specially when the number of contending devices is fairly high. We have proposed a novel OFDMA based IEEE 802.11 enhancement with a complete distributed coordinated function (DCF). Our DCF can allow multiple concurrent transmissions or receptions to reduce collisions and consequently improve the throughput and delay significantly. We have developed a complete analytical model of our proposed DCF using a discrete time Markov chain and demonstrated the effectiveness and superiority of the proposed DCF for access point based operations of IEEE 802.11. Finally, we have extended our work to support ad hoc operations of WLANs.
Our new MAC can incorporate multiple concurrent transmissions or receptions in a dynamic manner and can adjust the collision probability based on the traffic load when nodes are endowed with a single half-duplex radio only.
Here we provided a complete analytical model of our proposed DCF using a discrete time Markov chain model.
we discuss the challenges associated with integrating multiuser OFDMA in a single cell IEEE 802.11 based wireless ad hoc network and propose a new, dynamic and robust approach to improve it.
we made a detailed study of the performance comparison between various proposed contention resolution schemes - DCF, CONTI, k-EC, and PREMA.
We are a multidisciplinary team, from different backgrounds and different institutions!