| With the rapid development of mobile Internet,voice and video,HD live broadcasting,mobile games and other services enrich people's lives,but also it puts forward more and more requirements for the quality of information acquisition and transmission,which is the challenge facing the next generation of mobile communication systems.Distributed antenna systems can enhance network coverage and improve spectrum efficiency and power efficiency.It is one of the key technologies for mobile communication.The key technologies of synchronization.in distributed multiple antenna system is studied.Firstly,the development history and research status of centralized and distributed multiple antenna technology are introduced.In addition,the basic architecture of distributed multiple antenna system and key synchronization technologies are summarized.Secondly,the key synchronization techniques in MIMO multiple antenna systems is studied.According to the fading characteristics of the wireless channel and the modeling of the fading channel of the distributed multiple antenna system,several typical timing synchronization algorithms of OFDM system are introduced.In addition,the synchronization algorithm of the multiple antenna system is also analyzed.Then,the downlink synchronization algorithm of distributed multiple antenna system is studied.According to the characteristics of distributed multiple antenna system,two timing synchronization schemes are designed,one of which is a cyclic shift-based training sequence synchronization scheme;the other is a ZC sequence synchronization scheme based on different root numbers.A synchronization algorithm based on threshold decision is proposed and it is applied to these two schemes.Under different channel conditions,the timing synchronization performance of the two schemes is analyzed by simulation.The simulation results show that the former scheme is better than the latter scheme on timing synchronization performance.Finally,the synchronization technology of distributed multi-antenna multi-user systems is studied.A cooperative transmission timing method is proposed,which makes the propagation time difference between different RAUs arriving at the user less than the duration corresponding to the cyclic prefix.For the two-user scenario,the feasibility of the transmission timing adjustment is analyzed and the topological relationship of the two-user distribution area based on user pairing is derived.For the multi-user scenario,the necessary conditions for the transmission timing adjustment scheme are derived.In addition,a packet matching algorithm based on the user distribution region is proposed.The feasibility of the scheme is verified by simulation. |
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