Research On Power Control And Allocation Algorithm Of A Multimode Terminal In Heterogeneous Wireless Networks Cooperative Communication System

Currently, a large number of heterogeneous wireless networks coexist in a same region and are incompatible with each other, which hindered the full use of network resources. And the spectrum resource is limited. As a result, cooperative communication among heterogeneous wireless networks became a hot topic, and this paper mainly studied the power control and allocation of multi-mode terminal in cooperative communication. It analyzed the imperfection of existing power control and allocation algorithms and proposed two kind of new algorithm to solve this problem. It built a model to simulate the communication process, a multi-mode terminal transmitting data through multiple wireless networks in parallel in the WGN Rayleigh fading channels. Base on this model, it tested the performance of the two algorithms.The main work of this paper includes two parts:Firstly, based on the existing research about GA, it presented a kind of improved Genetic Algorithm(GA), named Directed Mutation Genetic Algorithm(DMGA). Different from other GAs, DMGA’s structure is unique. It introduced elitist method and inversion operator, and proposed a new kind of mutation operation, named directed mutation. To verify this algorithm, we used seven test functions in the MATLAB environment to test its convergence speed, search precision, stability and adaptability. As the test result showed, DMGA is faster, more accurate, more stable and more flexible than the existing GAs.Secondly, it built a model to simulate the communication process in parallel. Based on the purpose reducing the total power consumption and increase rate of the multi-mode terminal, it designed an evaluation function to evaluate power allocation scheme and proposed two new algorithms for power control and allocation, one is based on the Lagrange function method and the other on DMGA. For the performance, we take the following aspects into consideration: the total power consumption, the total transmission rate, the energy efficiency, the average error rate and the outage probability on the terminal. It made a comparison among the average allocation method, the allocation algorithm in literature [30], Lagrange function method and DMGA in this paper. As the test results showed, the Lagrange function method always had the best performance on these five aspects, DMGA is the second. And, Lagrange function method is the fastest, but it just can be used in very harsh conditions. Comparatively, DMGA is more universal. In addition, we also made another comparison between single network communication and cooperative communication with multiple networks. As the result shows, cooperative communication with multiple networks always performs better.