Dynamic channel allocation strategy for quality of service enhancement in wireless ad hoc networks

Abstract

The quality of service (QoS) is a momentous performance index of wireless ad hoc networks. However, unreasonable channel allocation will degrade the QoS. During the process of channel allocation, if user requests for idle channels are rejected, the QoS will lower accordingly. In this paper, we propose a dynamic channel allocation strategy for QoS enhancement to enhance the QoS and reduce the rejection rate of idle channel requests. First of all, the channel availability model is modeled as a Continuous Time Markov Chain in a bid to calculate the channel availability which is used to compute the channel availability factor (CAF) and the channel availability threshold (CAT).Then, the dynamic channel allocation process is achieved based on the comparison result of CAF and CAT. Ultimately, the QoS is guaranteed by exploiting the earliest deadline first algorithm to forward packets and enhanced by using the packet segmentation algorithm to divide packets into packet flows. The simulation results prove that the proposed channel allocation strategy increases the packet delivery ratio and throughput, decreases the end-to-end delay and total overhead and shows a QoS enhancement than existing schemes. K E Y W O R D Schannel allocation strategy, channel availability, QoS, wireless ad hoc network INTRODUCTIONWireless ad hoc network is composed of mobile nodes communicating with each other via wireless links without central node and fixed infrastructure support. It has a broad application prospect in the field of military communication and disaster relief due to the merits of data forwarding through relay node and self-healing function. Multi-interface multichannel wireless ad hoc network allows mobile nodes to share multiple common channels. Therefore, mobile nodes can send and receive the packets at the same time which can reduce the delay and improve the throughput. The quality of service (QoS) parameters include the packet delivery ratio, throughput, end-to-end delay, and total overhead. 1 QoS enhancement means the increase of packet delivery ratio and throughput and the decrease of end-to-end delay, and total overhead. However, irrational allocation of shared channels brings about request rejection, routing failure, and other problems, which will increase the end-to-end delay and total overhead and reduce the QoS. Therefore, how to design a sound dynamic channel allocation strategy and enhance QoS have drawn extensive notices.Channel allocation depends on the number of accessible frequency channels and the time slot of the available channel. In the existing literature, researchers have put forward different channel allocation strategies. Karaoglu and Heinzelman 2 made a research on the on-demand dynamic channel allocation mechanism suitable for nonuniform load in mobile ad hoc networks (MANETs) and creatively proposed a lightweight dynamic channel allocation mechanism (LDCAM) and a cooperative load balancing strategy. The interference level was proposed as the basis for channel allocation