Investigation Of Dynamic Channel Allocation Algorithms In The TD-SCDMA Trunking System.

Digital trunking system technology was rise in middle 1980s all over the world, getting a wide range of applications, and had achieved good economic and social benefits. As the third generation standard of mobile communication, TD-SCDMA is expanding to the digital trunking system with independent intellectual property right which not only promotes the technology development, but also meets the national development strategy. The cross-slot interference in the TD-SCDMA system is the hot and messy spot of the DCA research. The main work of this thesis is to analyze the interference in the TD-SCDMA trunking system and propose the improved hot cell algorithm and the DAD algorithm.Aiming at problems of the cross-slot interference, the thesis firstly analyzes the interference in the TD-SCDMA trunking system. Then, the simulation and comparison are done, and the simulation results show the cross-slot interference in TD-SCDMA trunking system is stronger than in the TD-SCDMA system. Finally, the strategies to eliminate or weaken the cross interference are analyzed by slow DCA and fast DCA.First of all, the three classic slow-DCA algorithms are studied and analyzed. Then an improved hot cell algorithm is proposed, which can increase the spatial isolation by sectoring the cross-slot cells. Finally the simulation is done based on this algorithm. The simulation results present the algorithms'performances have relationship with the proportion of cell type, and the average resource utilization ratio is rare increased by the improved algorithm.We study and analyze the existing fast-DCA algorithms which focus to the cross-slot interference, and a fast DCA algorithm based on dynamic area division (DAD) is proposed. It adjusts the boundary of area according to the traffic change in a cell. The algorithm makes the traffic adjust to the capacity of inner and outer area. Under the dynamic distribution of traffic in a cell, the simulation results show when the DAD has better performance than the other algorithms to decrease the cross-slot interference and increase the system capacity.