Eliminating the Performance Anomaly of 802.11b

Abstract

Abstract. In this paper, we propose a mechanism to eliminate the performance anomaly of IEEE 802.11b. Performance anomaly happens when nodes that have different transmission rates are in the same wireless cell. All the nodes in the cell might experience the same throughput even though their transmission rates are different because DCF of WLAN provides equal probability of channel access, but it does not guarantee the equal utilization of the wireless channel among the nodes. To reduce such a performance anomaly, we adjust the frame size proportionally depending on the bit rate. Additionally, our scheme eliminates the performance anomaly in multi-hop case. Simulation study shows that our scheme achieves an improvement in the aggregate throughput and the fairness.

Determination of Performance Enhancement in Ieee 802.11 Multi-Rate Wlan

“…T tot (6) According to [4] the useful throughput P i achievable by any host depends on the number of all hosts in the network and is given by:…”

“…The limitation of the algorithm is that it only schedules transmission of packet from or to a device if it has not used up all of its available time. A maximum transfer unit (MTU) adjustment proportionate with the transmission rate is proposed in [6]. Their solution overcome the performance anomaly but did not address fairness problem in a multi-rate case.…”

Resolving Performance Anomaly Using ARF-Aware TCP

“…Yoo et al proposed a scheme to eliminate the performance anomaly [4]; the authors insist that performance anomaly can be eliminated by adjusting the frame size. In the study, they proved that the aggregated throughput becomes higher when it is resolved.…”

“…To resolve the performance anomaly, channel utilization among the nodes should be equally distributed. Recent studies [7,6,5,3,4] on performance anomaly focus on resolving the anomaly using QoS adaptation at MAC layer.…”

Queue Management Mechanism for 802.11 Base Stations

“…This is the so called Multi-rate MAC throughput anomaly that is the result of the slower nodes taking longer to transmit frames than do faster ones. Some solutions for this problem [4], [5] include the modification of the link layer frame size [5] as well as that of the contention window, although these require changes in the standard.…”