Power control for wireless data

With cellular phones mass-market consumer items, the next frontier is mobil e multimedia communications. This situation raises the question of how to d o power control for information sources other than voice. To explore this i ssue, we use the concepts and mathematics of microeconomics and game theory . In this context, the qualify of service of a telephone call is referred t o as the "utility" and the distributed power control problem for a CDMA tel ephone is a "noncooperative game." The power control algorithm corresponds to a strategy that has a locally optimum operating point referred to as a " Nash equilibrium." The telephone power control algorithm is also "Pareto ef ficient," in the terminology of game theory. When we apply the same approac h to power control in wireless data transmissions, we find that the corresp onding strategy, while locally optimum, is not Pareto efficient. Relative t o the telephone algorithm, there are other algorithms that produce higher u tility for at least one terminal, without decreasing the utility for any ot her terminal. This article presents one such algorithm. The algorithm inclu des a price function proportional to transmitter power. When terminals adju st their power levels to maximize the net utility (utility - price), they a rrive at lower power levels and higher utility than they achieve when they individually strive to maximize utility.