Research On Multicast Beamforming With The Multicell Cooperation For LTE Pmr Networks

With the rapid development of wireless communication technology, LTE and other public mobile communication system have been very well-developed and widely used. As an important part of wireless communications,private network communication is developing rapidly.The demands of industry users about broadband multimedia services of voice, data, image and video become more urgent.In recent years, broadband private network system based on the core technology of LTE has been concerned widely.Group dispatch is the core business of broadband trunking system. The improvement of group dispatch performance has important theoretical significance and application value on the promotion of the development of broadband trunking system. Currently, the group users in different cells use different frequency to schedul in broadband trunking system. The success rate of handover,the performance of the cell-edge users, channel capacity still need to be improved. Same frequency scheduling can improve performance of group users. It has been widely studied in private network narrowband system, public E-MBMS system. Therefore, for the LTE broadband private network system. This paper presents a multicast beamforming algorithm with the multicell cooperation based on same frequency scheduling in order to improve the success rate of handover, the performance of cell-edge users, and the channel capacity.This paper researches about the single-group multicast beamforming algorithm with the multicell cooperation based on the same frequency firstly. In order to ensure the performance of each user of a group, and the algorithm uses the max-min fairness(MMF) guidelines. And the algorithm uses Angle Of Departure(AOD) as a shaping parameter based on the fact that users focus and angle information is easy to get.The problem is non-deterministic polynomial hard(NP-hard) problem. This paper proposes semi-definite relaxation(SDR) approach to solve this problem. Theoretical analysis and simulation results show that compared to non-cooperative scheduling in different frequency of the current broadband trunking system and the same frequency scheduling of single frequency network, multicell multicast beamforming algorithm based on the same frequency scheduling proposed in this paper can significantly improve the performance of cell-edge users and the channel capacity of the group users. And the performance of the proposed algorithm can be improved by reducing the angle between the users or increase the number of base station antennas.Secondly, this paper also uses the SDR method to research the multigroup multicast beamforming algorithm with the multicell cooperation based on Quality of Service(QoS) guidelines. Simulation results show that, compared with the method of non-cooperation, the algorithm can use the airspace resources better, reduce inter-group interference and improve the received SNR of cell-edge users.Finally, this paper proposes low complexity multicell multigroup multicast beamforming algorithm according to the demand of low delay and low complexity of the algorithm in the PMR system. The algorithm mainly takes the feature that group users crowd together to form clusters, the angle information of the users in a cluster can be approximately regarded as the same. Simulation results show that, when the interval of the users AOD is small, this method can reduce the computational complexity while maintaining system performance. But when the interval of the users AOD is large, the method can reduce the complexity with the degradation of system performance.