Improving TCP's Throughput and Fairness Stability in Vehicular Network

Abstract

Throughput and fairness performance of transmission control protocol (TCP) worsens critically under vehicular environment due to its weakly bounded congestion threshold parameter, rate reduction approach and congestion recovery algorithm. In this paper, a new congestion control algorithm for vehicular networks, called VC-TCP (Vehicular customized -TCP) is proposed to overcome the limitations of the existing independent congestion control approaches. The VC-TCP implements a newer congestion threshold parameter, which regulates the spurious rate reduction due to an abrupt increase in RTT spike value. During the congestion control process, VC-TCP uses a new recovery algorithm and bandwidth utilization based rate reduction, which substantially improves the flow fairness of TCP traffic flows with different bandwidth utilization levels. The throughput, flow fairness, and packet latency performances of VC-TCP is evaluated against the standard Vegas congestion control approach under simulated vehicular scenarios. The simulation outcomes verify the performance improvement of the proposed VC-TCP approach against the standard TCP variants in the different facets of the vehicular environment.