The Algorithm Of Game Theory Power Control Based On Far-near Fairness In CDMA

In CDMA communication system, the users are identified by their different spread spectrum codes which are unique to each user, namely they are identified by the cross correlation of spread spectrum codes. As the spread spectrum code sequence is difficult to achieve completely orthogonal, namely the correlation of different spread spectrum codes is not zero, there would be multi-access interference. Additionally, CDMA communication system is a interference-limited system, that is to say that the interference directly influences the capability of this system and the QoS of the user in the system. Power control is the key technology to rid the near-far problem and multi-access interference, so power control plays an important role in CDMA communication system.The main research in this thesis is the power control base on game theory. Firstly, game theory and power control in CDMA system are introduced. Non-cooperative power control game algorithm in CDMA communication system and the algorithm based on price function of non-cooperative power control game are recommended next, proved the existence and uniqueness of the Nash Equilibrium. The user's utility is not Pareto optimal under the Nash Equilibrium in non-cooperative power control game algorithm; Although Pareto effectiveness is improved in the algorithm based on price function of non-cooperative power control game, but only considering the transmission power impact on user, it is easy to lead the system inequitable allocation of resources.For making the system more equitability allocate resources, solving the far-near fairness, the path gain and power of the terminal are both considered based on price function in this paper, the existence and uniqueness of Nash equilibrium of the new price function has been proved. In single cellular numerical results suggest the new algorithm can improve the capability of the system and solve the far-near fairness; terminals enjoy higher utility and lower transmit power relatively. In multi-cell it is also shows the superior performance.