Power Control Mechanism Research Based On Game Theory For Cognitive Radio

In cognitive radio networks,the premise of spectrum sharing between primary users and secondary users is that the interference generated by secondary users can not affect the normal communication of the primary users.Through a reasonable allocation of the users' transmission power,power control technology not only can reduce the interference,improve system capacity,but also can save power to extend the terminal battery life.In the spectrum sharing network,each user will compete for resources.As an effective mathematical analysis tool,game theory can solve the problem of resource allocation and maximize the benefits through the rational choice of strategy.In recent years,some literature has introduced game theory into the study of power allocation in spectrum sharing networks.This thesis adopts game theory to study the resource allocation of cognitive radio,then investigates the following three aspects:1.In this thesis,we focus on the interference problem in cognitive radio networks and optimize the utility function with nash equilibrium as design criterion.The Signal to Interference Noise Ratio(SINR)threshold is introduced into the design of the utility function.The algorithm not only reduces the transmission power of the secondary users,but also avoids the large interference to other users due to the high transmission power,and makes each user's SINR value higher than the threshold.When the number of users is small,the SINR value is improved by adjusting the threshold factor of SINR,and the network resources are fully utilized.In addition,compared with the other two algorithms,this algorithm has better anti-noise performance and higher system capacity.2.The existing power control mechanism only considers the secondary users' participation and ignores the important role of the primary user in power control.In this thesis,the primary user is included into the power game mechanism.In the stackelberg game mechanism,the primary user is set as the leader,and the secondary user is set as the follower.The primary user sets the interference price to share the spectrum resources to the secondary user,and the secondary user accesses the primary users' spectrum by paying the corresponding fee.In the process of multiple secondary users' power control game,the main user monitors the interference generated by the secondary users,and dynamically adjusts the price factor to ensure that interference does not exceed the threshold,not only to ensure their own communication quality but also receiving a better revenue.3.In this thesis,a joint rate and power control algorithm based on game theory is proposed to solve the problem of resource allocation in cognitive radio networks.According to the difference of power and rate resources,different cost factors are designed respectively,and the interference constraints are introduced into the power cost factor,which makes the system more reasonable to the user's punishment mechanism.The proposed algorithm not only provides a variety of transmission rates,but also reduces transmission power as well as the interference to other users,and obtains a large system gain.And all the user's SINR values are above the threshold to ensure the normal communication of the user.