Impact of Secondary User Block on the TCP Throughput in Cognitive Radio Sensor Networks

Abstract

The cognitive radio sensor network (CRSN) has emerged as a promising solution to overcome spectrum under-utilization and spectrum scarcity problems in a resource-constrained wireless sensor network. In CRSN, TCP has to cope with a new type of packet loss due to the primary users arrival, known as secondary user blocking loss (SBL), otherwise It leads to significant TCP throughput degradation. In this paper, two main contributions are provided on the modeling of SBL and throughput evaluation of transport layer protocol for CRSN. First, it is identified two main factors of SBL and the probability of them is modeled by a discrete-time Markov chain. Second, a new congestion control algorithm is proposed to distinguish between actual congestion from the wrong congestion due to the SBL by considering the dynamic nature of CRSN. The obtained results through proposed model are verified using the COGNS framework based on NS2, which is a simulation framework for cognitive radio sensor networks. The proposed algorithm is compared with some of the well-known transport protocol TFRC-CR, OHTP and TCP Reno. The results confirm that our proposed algorithm is the best among them.