MOBILE VIDEO POWER CONSUMPTION OF MULTI-RATS OVER HETNETS

Abstract

As mobile video streaming becomes a growing segment of mobile traffic, next-generation mobile technology must handle demand for more reliable, higher quality data. Furthermore, as the number of smartphone users increases, network congestion increases. This causes latency and jitter in video delivery, decreasing user Quality of Experience. One solution to the problem of network congestion is to use heterogeneous networks (HetNets) to leverage all network technologies available, including 3G, 4G, and WiFi. By switching quickly between them based on network conditions or utilizing them simultaneously to increase the reliability, quality, and throughput of data, the user Quality of Experience can be improved. These implementations are called multiple radio access technologies (multi- RATs) over HetNets. However, the cost of using multiple technologies is power consumption, as the differing architectures of the RATs consume varying amounts of power. This study sought to minimize battery drain by determining metrics at the transport layer that may trigger increased power consumption. These were combined with metrics at lower and upper layers for a cross-layer approach. In order to measure the power consumed, a test device streaming a variety of video clips was measured with software and hardware measurement devices. 3G UMTS, 4G LTE, and WiFi were tested under varying signal strengths. Overall, WiFi consumed the least amount of current drained while UMTS had the greatest. Furthermore, video stages with different current consumption characteristics were determined. In order to evaluate the possibility of using TCP metrics to determine triggers in current consumption, TCP message packets were evaluated. Most notably, TCP Zero Window, Lost Segment, and Retransmission messages noted increases in current drain. Thus, the transport layer can be used to measure and extract metrics for improvement.