Power Allocation Methods For IDMA Based Multi-beam Satellite Communication Systems

Broadband satellite network is a typical system of bandwidth limited andpower limited. How to effectively use the precious communication resources isan urgent issue to be solved, while ensuring the quality of all kinds of services atthe same time is also needed. Multiple access method of broadband satellite canremarkably improve the channel utilization, which provides a technical guaranteefor effective utilization of wireless resources. However, there are some technicalbottlenecks in the existing satellite systems. For instance, to eliminate mutipleaccess interference (MAI), the system of Code-Division Multiple Access (CDMA)has to pay tremendous computational cost involved in multiuser detection(MUD); moreover, the structure of Time-Division Multiple Access (TDMA)needs accurate frame synchronization and complex slot scheduling algorithms.Interleave-Division Multiple Access (IDMA) derives from CDMA. As anew wireless access technology, the key thought of IDMA is to use differentinterleavers for distinguishing different users. Furthermore, IDMA solves theproblem of MAI at a very low computational complexity, and provides more andbetter services for users in the limited resources. Considering the advantage ofIDMA technique, this paper introduces IDMA into broadband satellitecommunication networks. Meanwhile this paper establishes a simulation modelof IDMA-based satellite communication system, and then derives the expressionof system capacity by taking the mobile satellite communication channels intoconsideration. Analysis and simulation results of MATLAB show that IDMAmethod can achieve a better communication performance and higher capacity at alow on-board processing complexity than CDMA method in satellitecommunication environment.However, in IDMA-based satellite communication systems MAI andrainfall attenuation are inevitable, and effective power control is the keytechnique to solve the problem. In light of this, several typical multi-beam powerallocation algorithms are studied in this paper. Based on them, this paper notonly proposes a novel power allocation algorithm by combining the technique ofSINR evolution and load balance, but also builds the GUI simulation platform ofthe algorithm. The main goal of the proposed scheme is to provide sufficienttransmission quality to as many mobiles as possible, even for the users sufferingheavy rain attenuation. In comparison with the tradition power allocationschemes, above analysis and simulation results show the proposed scheme canguarantee high power efficiency even in heavy rain attenuation conditions, while illustrating the high efficiency of CBC MUD. Furthermore, based on the SINRevolution technique and the diversity of attenuation in different cells, theproposed scheme can make accurate estimation of available resource consideringthe effect of MUD, leading to low outage probability.The related result of this article, to some extent, provides a valuablereference solution for the next generation broadband satellite communicationsystem with larger capacity, more business, and higher speed of traffic.