Research On Radio Resource Management In New Generation Wireless Communication Networks Based On MIMO/OFDMA

With the rapid development of wireless communication, internet and multimedia, the modes of new generation mobile communication networks become diverse, high-speed, flexible and high efficient. Orthogonal frequency division multiplexing (OFDM) and multiple-input multiple-output (MIMO) have been acknowledged as two major information transmission and processing techniques for next generation wireless communication networks, thus there are many problems to be faced for radio resource management. Therefore, the schemes of radio resource management in new generation wireless communication networks based on MIMO/OFDMA are researched in this dissertation.Firstly, according to the architectures and communication services of new generation wireless communication networks, some new research areas and status of radio resource management in new generation wireless communication are analyzed, including: integrated radio resource management based on time, frequency, space dimensions of MEVIO/OFDM, QoS aware based adaptive channel allocation techniques and energy efficient integrated scheduling technique.Secondly, for the characteristic of OFDMA technique, the OFDMA based systems can allocate dynamically subcamers to users in terms of the channel quality and QoS requirement. A novel algorithm is proposed which can guarantee users' QoS requirements. Simulation results show that the algorithm improve the system's throughput and guarantees the fairness among users while not increasing its computation complexity.Thirdly, users' services can be divided into high speed and low speed services group in terms of the velocity of users. Since their channel states vary quickly for high speed users, the channel state information which is fed back by the receiver can not show the real-time condition so that can not guarantee system's performance. At the same time, if radio resource allocation is fully based on channel state information, these increase the needed number of feedback bits and lead to feedback overhead. Therefore, downlink radio resource allocation systems based on MIMO and related schemes are designed. The radio resource allocation mechanism allocates distinctly radio resource to high speed group and low speed group and adopts the corresponding methods respectively.Fourth, for MIMO spatial multiplexing systems, channel state information should be estimated at the receiver and fed back to the transmitter. Channel estimation error usually exists in practical systems, which leads to the degradation of the power allocation at the transmitter. In this dissertation, the power allocation problem is presented by adopting the factor of channel estimation, and a greedy power allocation algorithm is proposed to maximize the system data rate. It is showed that the algorithm can guarantee each data stream bit error rate requirement.In order to meet users' QoS requirements in multiuser MIMO systems and reduce the multiuser interference, the efficient multiuser transmission schemes are needed. However, most of the current techniques respectively consider the physical or media access control layer, which can not guarantee QoS requirement and maximize the systems throughput. A cross-layer transmission method for multiuser MIMO systems is proposed by considering jointly the physical and MAC layer, which optimizes the system performance.At last, the conclusion is made and future work is proposed.