Research On Resource Allocation Technology In OFDM Systems

Orthogonal frequency division multiplexing(OFDM) technology has faster transmission rate, higher bandwidth efficiency and stronger anti-jamming capability, and is becoming one of the most important technology of the next generation wireless communication network. However, because of the wireless channel multipath fading, Doppler effect and a variety of noise generated by the superposition of interference, more advanced radio resource management should be used to enhance the effectiveness of the system in this complex channel. In order to improve the bandwidth efficiency of the system, radio resource allocation in OFDM system makes full use of space, and other resources in the frequency domain, and received widespread attention. In this paper, the issue of dynamic subcarrier allocation of the radio resource allocation in OFDM system was deeply studied, the main work is summarized as follows:Firstly, we research the greedy search algorithm of dynamic subcarrier allocation and propose two algorithms: maximum average channel gain(MAG) algorithm and maximum channel gain variance(MGV) algorithm. Average channel gain and channel gain variance are used by the two dynamic subcarrier allocation algorithms respectively to set the assigned priority of users, in this way, at the condition of maximizing system capacity, the search size and the computational complexity are decreased.Secondly, we research the fairness of radio resource allocation in OFDM system, and propose a fair dynamic subcarrier allocation algorithm based on the Rhee algorithm: users fair allocation order algorithm. Under the condition of maximizing system capacity, this algorithm realize the requirements of system fairness and decrease the complexity by using the forward reverse allocation order which is relatively fair.Finally, in view of the Shen algorithm, we propose a Hungarian algorithm and max-min capacity with proportional rate constraints algorithm combined algorithm. This algorithm makes full use of the advantages of the Hungarian algorithm to maximize the coefficient matrix matching, if the number of users in the system is much smaller than the number of subcarriers, compared with the original algorithm, it can achieve the same system capacity and proportional rate, if the number of subcarriers is equal to the number of users, the effectiveness of the system is improved.