| In recent years, with the rapid development of mobile communication technology,more and more wireless terminal equipments access to the communication network,resulting in a serious lack of spectrum resources. At the same time, most of licensedspectrum under the existing fixed spectrum allocation mechanism is idle, makingspectrum efficiency extremely low. In order to ease the tense situation of spectrumresources, cognitive radio technology comes into being, which is a kind of moreintelligent communication system that can sense and detect the idle spectrum that cannot be used by primary users with multi-dimension in the surrounding environmentfrom the time domain, frequency domain and airspace. CR can intelligently use the idlespectrum in a certain way in the case of not causing harmful interference to primaryusers, And this significantly improves spectrum utilization. As an important part ofcognitive radio technology, channel allocation can greatly improve the performance ofthe communication system through using reasonable and effective mechanism.In cognitive radio network, each second user rationally choose their own strategyto maximize their benefits by gaming constantly. This paper transforms channelallocation problem of second users into the corresponding Cournot Game Model, andproposes an improved spectrum demand function, enabling second users to consideravailable bandwidth of the system during gaming. The second users game mutuallyaccording to their own benefit function, and eventually reach the Nash equilibrium thateach second user gets the combination of the best strategies of the bandwidth.Experimental simulations demonstrate that compared with the original algorithm, theoptimal bandwidth allocated to the second users can adaptively adjust to the availablebandwidth of the system, with some flexibility.In the channel allocation algorithm of joint power control, most algorithms use theinterference temperature model to limit interference to primary users, which is verydifficult to set limits of interference temperature in practice. Parts of algorithms use theoutage probability to ensure the quality of service of primary users, but they do notconsider the QoS requirements of the second users, causing that parts of the secondusers can not communicate normally in the assigned channel. To solve this problem, thispaper proposes an improved channel allocation algorithm to ensure second users’ QoSrequirements. The algorithm considers the QoS requirements of second users as well as primary users’ outage probability by constructing a system utility function. Channelallocation problem eventually is converted to solve the corresponding convexoptimization problem. Experimental simulations demonstrate that compared with theoriginal algorithm, in the case that primary user’ outage probability and transmissionpower of the system are both the same, the system efficiency and the number of secondusers meets the QoS requirements both have improved to some extent. |
