Pipelined backoff scheme for bandwidth measurement in QoS enabled routing towards scalability for MANets

Abstract

MANets are very sensitive to control overhead packets due to its limited capacity. If available bandwidth is not accurately estimated, nodes will accept extra QoS requests and network will be overloaded. To improve the available bandwidth and to reduce the control overhead associated with the backoff scheme employed in MAC (Medium Access Control) layer; pipelined concept is applied to backoff procedure. Pipelined process also reduces collision probability. When the medium is busy, remaining nodes start the contention procedure in parallel for the next packet transmission. This reduces the channel waiting time. Bandwidth loss due to collision, pipelined backoff and idle time synchronization are estimated and final available bandwidth is calculated. This bandwidth measurement algorithm is integrated into routing protocol called enhanced QoS AODV (Quality of Service Ad hoc On demand Distance Vector) to find the best route based on bandwidth constraint. Simulation results show that the proposed algorithm improves the performance of the network in terms of throughput, packet delivery ratio, effective bandwidth utilization, energy consumption for different number of nodes.

Intelligent Paging Backoff Algorithm for IEEE 802.11 MAC Protocol

“…Their algorithm depends on applying the pipelined concept for the backoff procedure when the medium is busy, remaining nodes in the network initiate the contention procedure in parallel way for the next packet transmission. [12] M. Masadeh, S. Manaseer and A. Momani [3] proposed the Smart Adaptive Backoff Algorithm (SABA). This algorithm attempts to achieve the best performance by combining the exponential, logarithmic and linear increments in the attempt to achieve the most adequate increment behavior.…”

“…The rest of figures (11,12,13) show another performance metric called the network overhead, this metric measures the number of packets carrying control messages (route request, route reply, and route error) for route discovery and routing to the number of packets carrying data [15]. Figure 12 shows that IPBA's, SABA's and BEB overhead is the same for more stable areas (50 m/s) but IPBA's outperform PLEP's by 2.5% for the same case.…”