Effect of Carrier Sensing Range on the Throughput of Multi-hop Wireless Ad-Hoc Network

Carrier sensing is a fundamental mechanism in Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocols and it has been used as an effective way to reduce collisions and exploit spatial reuse in wireless networks. The size of the carrier sensing range has a great effect on the network performance. This paper investigates the effect of sensing range on the throughput of multi-hop wireless ad hoc network by considering two fundamental issues in Medium Access Control (MAC), i.e., collisions and spatial reuse, in terms of persistent probability, transmission range and Exponential Increase Exponential Decrease (EIED) back-off time. Markov chain models were used to derive the duration time, transmission probabilities, transition probabilities and steady-state probabilities of the states of node as well as the throughput. Simulation results show that throughput increases along with increase in sensing range R8 , but when it reach its maximum value, its start decreasing with increase in the sensing range. This means that the larger the sensing range, the smaller the possibility that a new transmission attempt to interferes with some ongoing transmissions. Furthermore, smaller sensing range with a larger transmission range means more nodes have to defer their transmissions when one node is transmitting, which leads to lower spatial reuse and consequently decreases throughput. Similarly, smaller sensing range means more transmission hops which leads to more collisions. In the other hand, throughput decreases with increase in transmission range, number of nodes and back-off time.