Optimization of an adaptive link control protocol for multimedia packet radio networks

Packet radio technology is currently used in a wide range of tactical military communication systems, including SINCGARS, EPLARS, and NTDR, for the transfer of data based messages across the battlefield. The DARPA GloMo program is also investigating the use of this technology for the transfer of multimedia voice, data and video traffic among dismounted infantry users in ad hoc mobile radio networks. A key aspect of the GloMo program is the development of adaptive protocols that minimize energy consumption and maximize the battery life of a user's handheld terminal. Under sponsorship from DARPA and internal research and development funding from ITT Industries, we have developed a unique set of algorithms to minimize energy consumption by adaptation of physical and link layer protocol parameters within a packet radio network. This paper presents an overview of these algorithms and then presents a design and modeling approach, based upon Taguchi (1984, 1987) techniques, for the optimization of these algorithms. We present a metric that optimizes performance as a function of the number of successful information bits at the output of the decoder per unit of energy transmitted. When applied to hand-held or portable, packet radio communication equipment, this metric provides improved performance with respect to battery life and signal intercept performance. OPNET models are used to run a set of matrix experiments to arrive at an optimized set of design parameters for operation of theses adaptive transmission protocols in a tactical environment.