Selfish Routing and the Price of Anarchy
EURASIP Journal on Applied Signal Processing
IEEE Transactions on Information Theory
We consider a wireless collision channel, shared by a finite number of mobile users who transmit to a common base station. Each user wishes to optimize its individual network utility that incorporates a natural tradeoff between throughput and power. The channel quality of every user is affected by global and time-varying conditions at the base station, which are manifested to all users in the form of a common channel state. Assuming that all users employ stationary, state-dependent transmission strategies, we investigate the properties of the Nash equilibrium of the resulting game between users. While the equilibrium performance can be arbitrarily bad (in terms of aggregate utility), we bound the efficiency loss at the best equilibrium as a function of a technology-related parameter. Under further assumptions, we show that sequential best-response dynamics converge to an equilibrium point in finite time, and discuss how to exploit this property for better network usage.