Research On Mobile Fronthaul Technology Based On Digital Quadrature Filtering And Analog Angle Modulation

In recent years,the rapid development of mobile Internet and Internet of Things in China has brought wide application scenarios to 5G networks.As the core part of 5G centralized wireless access network,mobile fronthaul transmission also faces the challenges of large capacity,high spectral efficiency,low cost and low delay and so on.In order to meet these needs,domestic and foreign researchers have invested a lot of energy in the simulation of optical wireless mobile forward network.However,the existing analog mobile fronthaul networks still have problems such as high implementation complexity and complex transmission network scenarios.And with the increase in the number of aggregated channels and the modulation order,the transmission performance cannot meet the future transmission needs.These problems are all urgently needed to be solved by 5G mobile fronthaul network.Based on the in-depth study of analog mobile fronthaul,this thesis presents an analog mobile fronthaul which uses digital orthogonal filter banks for channel aggregation of multi-channel signals.Compared with the traditional FFT/IFFT channel aggregation scheme,j 8u can simplify the channel aggregation process and reduce the processing delay by inputting a preset digital orthogonal filter banks into the processor.In order to solve the complex problem of the aggregation channel in the existing analog mobile fronthaul transmission,this thesis uses the digital orthogonal filter banks to aggregate the channel of various bandwidth signals so that we can realize the multi-bandwidth analog mobile fronthaul transmission.In the existing mobile fronthaul applications,the data transmitted by the mobile fronthaul system not only contains the users' data,but also contains the control and management information for the calling process.Therefore,this thesis puts forward a digital orthogonal filter banks aggregate channel in analog mobile fronthaul with control information.After QAM modulation,the control information of mobile fronthaul transfer will perform FDM channel aggregation with aggregated signals.In practical applications,the noise loss budget of the total transmission link in the mobile fronthaul network should be as small as possible.And with the increase of the sub-carrier modulation order,the quality requirements of the transmission signal also will be higher.Thus,this thesis proposes to apply angle modulation to analog optical links to improve the signal-tonoise ratio of the received signal and increase the link loss budget.The above schemes have built a test environment through simulation,and the DSP part and the optical transmission link part are jointly debugged.From the simulation results,it can be concluded that using this solution to aggregate multi-channel mobile signals for analog mobile fronthaul,the received signal can meet the mobile fronthaul requirements,and the received optical power and noise loss budget are within the scope of the agreement,which meets the system design requirements.