Design And Implementation Of Receiving And Transmitting System For Police Micro Base Station

Although the mobile communication network has become increasingly mature nowadays,the traditional macro base station technology still can not meet all the needs of users.For instance,it lacks pertinence and costs too much when constructed in some areas with low population.In the project,the traditional macro base stations aren't able to meet the demand of police that they need to realize the unified management of the specified user group,and carry the base station with their cars or even bags.In view of this situation,a police micro base stations transceiver system based on OpenBTS software protocol stack architecture and USRP software radio hardware platform is designed and implemented.First of all,the project requirements of the receiving and transmitting system for police micro base station are shown in this paper.Based on this requirement,two different system architectures are proposed.After comparison,the author finalizes the OpenBTS software protocol stack architecture as the core of the micro-base station design and then the software and hardware platform of the scheme are determied.In general,the scheme has the advantages of low development cost and short development period,and besides,the OpenBTS network are easy to redevelope.Secondly,the network system based on OpenBTS is constructed,and its basic functions are measured.The results show that the system have been accomplished all the functions,including voice calls,the SMS transceiver and traffic management.Thirdly,the parameter configuration of the system under different scenarios are discussed,and then this thesis studies the call data flow in OpenBTS system and focus on the analysis of the transceiver module.This module acts as a bridge between OpenBTS and USRP and plays a vital role of the whole system.Next,the coverage of the system is measured in three different environments,then the networking construction of OpenBTS is studied.After that,the number of carrierfrequency and USRP needed in theory under different requirements is discussed according to the Erlang formula.Finally,the OpenBTS network has been optimized,which is the characteristics of this article,the main contents are as follows:1.The logical channel allocation strategy has been optimized to make the system more stable.At the same time,the business processing capabilities have been strengthened.2.According to the actual needs of the project,the function modules for police are added,including group SMS module,grouping management module and timing management module.3.The security of the system is discussed,according to the results,a set of user security management scheme have been designed and implemented.In general,the research work of this paper has achieved initial results,its function can meet the basic needs of the police project,which laying a solid foundation for the next study for the team.