Distributed fair scheduling with distributed coordination function in WLAN

With the rapid growth of the Internet and other Internet-protocol related applications, many improvements have been made at the data link layer in wireless systems to support a wider variety of data services. However, further improvements in packet data admission, scheduling and policing between nodes in the network are necessary to maximize throughput and user satisfaction. In the above three, scheduling has the greatest impact on system throughput. Also, proper scheduling can provide user satisfaction. In this paper, a combination of an Inter Frame Space (IFS) based Distributed Fair Scheduling (IDFS) with the backbone of IEEE 802.11 DCF is designed to achieve better performance in terms of throughput and fairness. Such an attempt has not been made so far in the literature up to our knowledge. By implementing this mechanism, it is proved that improved throughput is achieved compared to traditional DCF and Inter Frame Space (IFS) based Distributed Fair Queuing (IDFQ) separately. It involves a Cross-Layer Approach by considering the physical characteristics of wireless channel and designing a mapping function at Medium Access control (MAC) layer. The inclusion of weighted fair service discipline in the system remedies the performance anomaly problem of IEEE 802.11 Medium Access Control. The proposed methodology avoids collisions of packets to the greater extent and thus helps to improve the throughput in the simulated environment. It is also shown that better performance measure is achieved when validated with NS2 simulations.