Performant TCP over Wi-Fi Direct

Wi-Fi Direct has been serving a progressively wide range of applications such as device-to-device file sharing, face-to-face interactive gaming, and wireless projection. However, when TCP meets Wi-Fi Direct, we find that two independent control loops exist, i.e., the transport-layer control loop and the link-layer control loop. First, these functionally redundant loops result in spectrum inefficiency. Second, the lack of effective information interaction between layers results in local optimal. To tackle these issues, this paper proposes Wi-Fi Direct TCP (WDTCP), a performant TCP that provides a full protocol design of the acknowledgment de-redundancy and explicit-capacity-based congestion control. WDTCP tightly couples the two control loops by capturing the WiFi Direct’s key feature of one-hop communication. Evaluation results demonstrate that WDTCP can maximize bandwidth utilization while keeping low latency. For instance, compared to legacy TCP, WDTCP improves throughput by up to 49.2% and reduces average and 95th latency by up to 32.4% and 50.7%, respectively.