| Cellular mobile communication system adopts frequency multiplexing technology and wireless networking based on "cell",which increases the system capacity and improves the spectrum utilization rate.With the development of multiple access technology and its application in cellular communication system,the performance of cellular mobile communication system is greatly improved.However,frequency division multiple access,time division multiple access and code division multiple access are one-dimensional multiple access technologies,which can not effectively solve the interference caused by multipath propagation and Doppler frequency shift in mobile communication systems.In this paper,the application of optimum frequency hopping patterns to cellular mobile communication system can eliminate the interference caused by multipath propagation and Doppler frequency shift compared with traditional cellular mobile communication system.In this paper,the construction method of optimal frequency hopping pattern based on algebraic theory is introduced,and a new theory of optimal frequency hopping patterns are established based on Costas sequence with ideal autocorrelation characteristics.The optimal frequency hopping patterns are obtained by using a two-dimensional cyclic shift method,which has ideal autocorrelation and cross-correlation characteristics.Then,the optimal frequency hopping patterns are applied to the cellular system.According to the maximum Doppler shift in the system,the number of cells in the group,cell radius,bandwidth,frequency,time slot,the number of users in the cell and the transmitting power of the base station,the optimal frequency hopping patterns of the users in the system are designed to ensure that the frequency hopping pattern of each user is two-dimensional orthogonal.By calculating the 2-D autocorrelation and cross-correlation of the optimal frequency hopping pattern,it is verified that the optimal frequency hopping patterns designed by 2-D cyclic shift of the Costas sequence based on algebraic construction have the ideal self-cross correlation and cross-correlation.The simulation results show that the application of optimal frequency hopping patterns in cellular mobile communication system can effectively solve the interference caused by multipath propagation and Doppler frequency shift in mobile communication system.If the optimal frequency hopping patterns are applied to cellular mobile communication system,the interference caused by multipath propagation and Doppler frequency shift can be solved without equalization and channel estimation technology,so the complexity of receiver can be greatly reduced and the system performance can be improved.The research in this paper plays a very important role in reducing the interference in cellular mobile communication system.The large-scale MIMO and intelligent reflective surface technologies proposed for future cellular mobile communication systems are also suitable for this communication system based on optimal frequency hopping patterns. |
