Research On Base Station Diversity Reception Technique In CoMp System

Coordinated Multipoint(CoMP)technology is an effective means which can eliminate inter-cell interference,improve the communication quality of edge users,and improve the overall performance of the system.It is one of the key technologies in the 5G communication system.At present,it has become a research hotspot in wireless communication system.When considering the practical application of the uplink CoMP system,it is necessary to jointly consider physical layer signal processing techniques between multiple receiving base stations(BSs)in the CoMP system,such as diversity receiving technology.In the future communication system,the deployment of the BS will be more intensive,and with the application of the massive antennas technology,the number of paths of the received signals that need to be subjected to the diversity processing in the uplink CoMP system will increase sharply,which causes the system to become much more complex,leads to big computation,and puts forward higher demands for hardware devices.Therefore,it is especially important to study the diversity reception technology of BSs in CoMP systems to realize a diversity reception system with less complexity.In this paper,for different uplink CoMP system application scenarios,the BS diversity reception in multi-BS CoMP communication is deeply studied.The main work of this paper is as follows:(1)Based on the characteristics of millimeter wave communication,aiming at the multi-BS receiving signal processing in CoMP system,a method of selecting the CoMP transmission node and diversity path based on the main-assistant BS is proposed.In this method,one of the CoMP group BSs is appointed as the main BS,and the others are assistant BSs(cooperative BSs).The diversity combining processing is conducted in the main BS.The assistant BS selects only one channel with the best channel condition to transmit to the main BS for signal diversity and avoids transmitting the receiving antenna signals of all the assistant BSs to the main BS,thereby implementing a less complex diversity receiving system.(2)For the cell adopting the relay transmission system,and we propose a CoMP diversity path selection method based on relay transmission.In this method,the uplink only uses the signal from the user to the main BS and the signal transmitted by the user to the main BS through the relay node for diversity combining,which avoids the system complexity brought by the transmission of the signals from the assistant BS to the main BS.(3)By using the MIMO-OFDM system space frequency block coding(SFBC)method,for the CoMP system,a method for adaptively modulating a transmitter by selecting different transmit antenna groups and subcarrier groups for different receiving BSs is proposed.In this method,antenna and subcarrier groups are grouped according to the code structure of the space frequency coding.And each receiving BS selects its own subcarrier group for independent signal measurement and performs diversity combining on different antennas,and does not need to perform diversity combining between BSs,thereby reducing the complexity of the receiving system.At the same time,under the premise of ensuring the required bit error rate of the system,the spectrum efficiency of the CoMP system is improved.