الگوریتم توزیع برق بر اساس تئوری بازی در سیستم femtocell

This paper studies the power control problem in femtocell system based on Nash non-cooperative game theory. It designs an utility function taking fem stations' transmit power as variable and relates it to the requirements of macro users' and fem users' signal to interference plus noise ratio (SINR). The utility also takes the impact of fem stations' location into account and improves the fairness of non-cooperative game. On this basis, this paper proposes a distributed power control algorithm and proves the existence and uniqueness of Pareto optimal point. The simulation results show that the algorithm improves the convergence speed and system performance through improving users' SINR.

Femtocells, are small cellular base stations and being widely used in the family rooms or small commercial organizations [1]. With reasonable distribution of femtocells’ transmit power, the interference in the femtocell system which is the biggest problem of its promotion can be properly reduced. Game theory, as one of the methods to distribute power, is widely used in the cognitive radio. Taking the similarities between cognitive radio and femtocells into account, it can be introduced into femtocell system. Ref. [2] uses Nash equilibrium to allocate power in cognitive system which can be introduced. Ref. [3] uses the Stackelberg mechanisms to allocate power. Refs. [4] and [5] introduce Nash equilibrium into femtocell system, but they just borrow the utility function from the cognitive radio without consideration of the differences between systems of cognitive radio and femtocell. Ref. [6] holds that game theory is a useful mathematical tool to deal with the interactive options and strategies of the users with conflicts of interests. This paper introduces Nash equilibrium into femtocell system and makes some improvements to the utility function. The penalty factor is introduced to control femtocells’ transmit power, making it tend to a stable value with dynamic iterations. It reduces convergence times compared with Ref. [2], while ensuring macro users’ service quality and improving fem users’ service quality [2].

As an emerging technology of 4G, femtocells are coming to people’s daily life, but the interference has become one of the major problems in its development. This article does research on the algorithm to allocate fem stations’ transmit power based on the non-cooperative game theory. The simulation has proven that through improving the utility function reasonably and proving the existence and uniqueness of Nash equilibrium, the algorithm improves the SINR of fem users and macro users, thus improving the whole throughput.