ITR: Power Efficient Multimedia Wireless Communications

Polytechnic University Of New York, Brooklyn NY

Investigators

Abstract

The large number and diversity of quality of service (QoS) measures present a significant challenge to the design and operation of multimedia wireless communications systems. Each information source (data, audio, video) has its own metrics of signal quality and the network has an aggregate measure of capacity for each source (for example, Erlangs of telephone traffic and data throughput). In addition to signal quality and network capacity, the battery life of a portable terminal has a major effect on the value of mobile information services to consumers. Existing knowledge of quality optimization is generally confined to studies of individual sources. In the 1990s, a significant body of knowledge was created on radio resource management for cellular telephone communications. More recently, the research community has turned its attention to wireless data and video. Each study focuses on one or two quality measures for one type of information: for example, power and distortion for video; power and throughput for data. This project takes a more comprehensive view by considering the collection of QoS measures to be a point in a multidimensional space. Given a system design and a set of operating conditions, the achievable points constitute a feasibility volume, with optimum points on the surface. Within this formulation, we study simultaneous transmission of data and video by analyzing projections of the volume onto various combinations of QoS dimensions including: video distortion; data throughput for each source; data utility for each source; total power dissipation (signal processing power and transmission power) in a terminal; number of simultaneous video transmissions at a base station; aggregate base station throughput; aggregate base station utility. The emphasis is on power efficient communications and the results provide guidance on joint adaptation of the following properties of terminals that transmit signals to the same base station: transmission power and rate in data terminals and transmission power, compression, and channel coding in video terminals.