An Optimized Virtual Scheme for Reducing Collisions in MAC Layer

Authors: M. Sivakumar, S. Saravanan

Abstract:

The main function of Medium Access Control (MAC) is to share the channel efficiently between all nodes. In the real-time scenario, there will be certain amount of wastage in bandwidth due to back-off periods. More bandwidth will be wasted in idle state if the back-off period is very high and collision may occur if the back-off period is small. So, an optimization is needed for this problem. The main objective of the work is to reduce delay due to back-off period thereby reducing collision and increasing throughput. Here a method, called the virtual back-off algorithm (VBA) is used to optimize the back-off period and thereby it increases throughput and reduces collisions. The main idea is to optimize the number of transmission for every node. A counter is introduced at each node to implement this idea. Here counter value represents the sequence number. VBA is classified into two types VBA with counter sharing (VBA-CS) and VBA with no counter sharing (VBA-NCS). These two classifications of VBA are compared for various parameters. Simulation is done in NS-2 environment. The results obtained are found to be promising. 

Keywords: VBA, sequence number, counter, back-off period.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1107289

References:

[1] Choi J, Yoo J, Choi S, and Kim C (2005), “EBA: An enhancement of the IEEE 802.11 DCF via distributed reservation,” IEEE Trans. Mobile Comput., Vol. 4, No. 4, pp. 378–390.
[2] XiaoY, Li H, Wu K, Leung K K and Ni Q , “On optimizing backoff counter reservation and classifying stations for the IEEE 802.11 distributed wireless LANs,” IEEE Trans. Parallel Distrib. Syst., vol. 17, no. 7, pp. 713–722, Jul. 2006.
[3] Baldwin R O, Davis N J, and Midkiff S E (1999), “A real-time medium access control protocol for ad hoc wireless local area networks,” Mobile Comput.Commun. Rev. (MC2R),Vol. 3, No. 2, pp. 20–27
[4] Calì F, Conti M, and Gregori E (2000), “IEEE 802.11 protocol: Design and performance evaluation of an adaptive backoff mechanism,” IEEE J. Sel.Areas Commun., vol. 18, no. 9, pp. 1774–1786.
[5] Krishna P V and Iyengar N (2008), “Sequencing technique: An enhancement to 802.11 medium access control to improve the performance of wireless networks,” Int. J. Commun. Netw. Distrib. Syst., Vol. 1, No. 1, pp. 52–70
[6] Fitzek F, Kopsel A, Wolisz A, Krishnam M, and Reisslein M (2002), “Providing application-level QoS in 3G/4G wireless systems: A comprehensive framework based on multirate CDMA,” IEEE Wireless Commun., Vol. 9, No. 2, pp. 42–47.
[7] Kleinrock L and Tobagi F A (1975), “Packet switching in radio channels:Part I—Carrier sense multiple access modes and their throughput–delay characteristics,” IEEE Trans. Commun., vol. COM- 23, no. 12, pp. 1400–1416.
[8] Krishna P V and Iyengar N (2008), “Design of sequencing medium access control to improve the performance of wireless networks,” J. Comput. Inf. Technol., Vol. CIT 16, No. 2, pp. 81–89.
[9] Mangold S, Choi S, Hiertz G R, Kle O, and Walk B (2003), “Analysis of IEEE 802.11e for QoS support in wireless LANs,” IEEE Wireless Commun.,Vol.10,No.6,pp.40–50.
[10] Zhu H, Li M, Chlamtac I, and Prabhakaran B (2004), “A survey of quality of service in IEEE 802.11 networks,” IEEE Wireless Commun., Vol. 11, No. 4, pp. 6–14.
[11] Vaidya N, Gupta S, and Bahl P (2005), “Distributed fair scheduling in wireless LAN,” IEEE Trans. Mobile Comput., Vol. 4, No. 6, pp. 616– 628.
[12] Pattara-Atikom W, KrishnaMurthy P, and Banarjee S (2003), “Distributed mechanisms for quality of service (QoS) in wireless LANs,” IEEE Wireless Commun., Vol. 10, No. 3, pp. 26–34.