Throughput stability and flow fairness enhancement of TCP traffic in multi-hop wireless networks

In the multi-hop wireless network, transmission control protocol (TCP) throughput stability and flow fairness performances are worsened due to slower flow convergence in the loss recovery phase and flat-rate reduction during the congestion control process. In this article, a combination of network-assisted and window utilization based congestion control approach, known as feedback assisted improved recovery + (FAIR+), is proposed to overcome TCP's limitations under multi-hop wireless networks. The proposed FAIR+ algorithm initiates the congestion control process based on the queue level notification of the relay node and trims down the sending rate based on TCP flow's utilization level. In the congestion recovery phase, the FAIR+ algorithm implements a newer window increment pattern that achieves a faster convergence rate than the existing RFC 6582 implementation. The throughput stability of the FAIR+ algorithm is validated using the duality model and multi-hop wireless simulation. The simulation results convincingly prove that the FAIR+ attains significant improvement in throughput, flow fairness, and end-to-end latency performance over the existing TCP variants (OQS, NRT, and Westwood).