STUDY AND SIMULATION OF JOINT NETWORK- CENTRIC AND USER-CENTRIC POWER CONTROL GAME FOR WIRELESS DATA NETWORKS

Abstract

Power control is one of the most important aspects of radio resource management in CDMA systems. With the advent of multimedia services in wireless CDMA networks, power control has assumed greater significance. A good power control scheme ensures efficient use of radio resources, thereby increasing the capacity of the system, extending the battery life of mobile terminal and mitigating near far effect. The power control problem should be modeled such that various services meet their respective Quality of Service (QOS) requirements. QOS can be defined as achieving required target Signal to interference plus noise ratio (SINR) or acceptable bit error rate in case of voice and maximizing the utility in case of data. In this dissertation work, non co-operative game theoretic approach has been used to deal the power control problem for wireless CDMA data service. In the wireless CDMA network, all the users would like to have a high value of SINR, while transmitting at lower power. So, they have to satisfy conflicting objectives. Moreover, the output of each user depends on his decision as well as the decisions of other users. Therefore, power control problem can be modeled as a non cooperative game. In this game all users act selfishly to maximize their utilities with respect to power. We have considered joint _,network centric- trier centric (NC-UC) power control Fame where users adjust their power to maximize their net ufility and networks adjust their power to maximize the revenue. The net result is a tradeoff between the two seemingly conflicting user-centric and network-centric objectives, which implies that the solution lies between the two extreme solutions of pure network-centric and user-centric methods. Simulation studies are carried out for NC-UC scheme with -throughput based utility function and 9aussian channel capacity utility function for single cell and multi cell CDMA systems. In multi cell systems, two different types of pricing strategies have been considered and the performance under hctndaf'is also evaluated. In, NC-UC scheme for single cell using `throughput based U U4y f unction, users with better channels obtain b:igher utility, transmit with lesser Fower but they pay proportionally more, compared to other users. For a multi cell system, we observe that network obtains its zevenue mainly from few users with best channels at global pricing 111 and for mini-max pricing, network trades off revenue for a more even resource allocation. Considering the single cell situation using c~.aussian channel capacity utility function, we observe that all users obtain equal viet ui7tility, payment, SINR at equilibrium unit price. In multi cell system, we observe that network collects equal revenue from all users at c~.lobal pricing and at mini-max pricing, equal revenue is obtained from few users with best channels and for other users lievenue decreases with increasing distance from base station. iv