Empirical Evaluation and Analysis of Application-Layer Delay Reduction Methods over Wireless Access Networks

Abstract

In this paper, we discuss the experimental results of application-layer delay reduction methods, which can reduce the delay during TCP applications. Due to the popularization of smart phones, Wireless Local Area Network (WLAN) access such as WLAN hot spot or WLAN tethering is increasing. This increase leads to a WLAN channel being shared by multiple data flows, resulting in the degradation of the communication performance. Specifically, the delay of the real time applications that communicate over TCP can be made longer. To reduce the delay, we developed three methods: reducing the amount of data to send, triggering TCP’s fast retransmission earlier, and returning TCP’s acknowledgment immediately. In our experiments, we measured the delay during the real time TCP applications connected with each other over WLAN and commercial fixed network and analyzed the effectiveness of our methods in the case of WLAN performance being degraded by the file transfer flow. Results indicate that our methods can reduce the 95th percentile of the delay by as much as 84%.