Research On Cross-layer Dynamic Resource Allocation Algorithm For Power Line Communication

OFDM is increasingly concerned as core technology to achieve power line communication. But traditional OFDM technology can’t overcome the time varying and frequency selective fading of power line channel. OFDM dynamic resource allocation can assign subcarrier, bit and transmitted power on the basis of the signal to noise ratio(SNR) of subcarriers of users. It can improve frequency spectrum utilization efficiently, satisfy customer’s service quality. Cross-layer resource allocation combined time domain with frequency domain can take count of upper layer to avoid unreasonable allocation of resource, which has became hot topics of OFDM system.In this thesis, resource allocation based on power line communication OFDM system is studied. After analyzing user’s scheduling strategy, a improved scheduling strategy based on utility function is proposed, which bring satisfying factor into index scheduling function to replace index weight factor to makeup new utility function. Scheduling strategy formulated on the basis of new utility function is delivered to physical layer as layer information. According to the controlling parameter offered by MAC layer, physical layer accomplish the allocation of sub-carrier wave, power and bit to achieve cross-layer resource allocationA media access control (MAC) layer dispatch strategy based on D-S evidence theory is proposed in this paper towards OFDM system. The strategy adopts three evaluation indexes to judge packet scheduling priority which including time delay, rate fairness and packet loss ratio. Through selecting membership function for every evaluation indicator to get the value of basic probability assignment values, and to merge the three evaluation indicators for judging, using the combination rule of D-S evidence theory. Then the results of judgment are delivered to physical layer as layer information. According to the controlling parameter offered by MAC layer, physical layer accomplish the allocation of sub-carrier wave, power and bit to achieve cross-layer resource allocation. By means of establishing power line communication (PLC) system model, emulation, and comparing with contemporary cross-layer resource allocation algorithm, the results indicate that the proposed two algorithms can both allot resources dynamically, and meet the demands of multi-service users as well as ensuring system performance. The performance of strategy based on D-S evidence theory is better than algorithm based on improved utility function.