Volume 5 - Issue 3
Hashing Based Distributed Backoff (HBDB) Mechanism for IEEE 802.11 Wireless Networks
- M. Devipriya
Department of Computer Science and Engineering National Institute of Technology Tiruchirappalli - 620015, Tamil Nadu, INDIA
306111051@nitt.edu
- B. Nithya
Department of Computer Science and Engineering National Institute of Technology Tiruchirappalli - 620015, Tamil Nadu, INDIA
nithya@nitt.edu
- C. Mala
Department of Computer Science and Engineering National Institute of Technology Tiruchirappalli - 620015, Tamil Nadu, INDIA
mala@nitt.edu
Keywords: WLAN, BackOff Algorithm and Contention Window.
Abstract
Binary Exponential Backoff (BEB) is the De-facto mechanism for contention control in IEEE 802.11
Wireless LAN. The exponential growth of ContentionWindow (CW) in all BackOff (BO) stages and
randomness in BO selection causes unnecessary waiting time, high collision rate and unfairness in
accessing the channel among the nodes. To overcome these anomalies, this paper proposes Hashing
Based Distributed Backoff (HBDB) algorithm. It allows a node to dynamically adopt different CW
values based on the collision probability. To choose unique collision probability value, linear probing
is used. The simulation results show the effectiveness of the proposed algorithm in linear and random
topologies under low, medium and high traffic scenarios.