Realization Of Analog-to-digital Transition In Wireless Private Network

The 350 MHz wireless trunked communication system is one of the critical means for real-time dispatch and delayering command of wireless communication for public security organs.With advantages of private network establishing,self-networking and quick deployment,it plays significant roles in day-to-day duty,emergency handling,security maintenance of major events,and key personnel protection,all of these helps the police categories at all levels achieve delayering dispatch and flexible response.China’s 350 MHz police wireless trunked communication system has been developing from analogue systems into the current digital systems in the past 3 decades,which substantially increased the command & control capability of public security organs at all levels and provided effective protection for the citizen safety across country.Also,the social progress,urbanization,residential density increase and extending of areas with complicated public order have put new and higher requirements for emergency handling and real-time response ability.Meanwhile,considering the financial investment return ratio of public services,we know deeply that the transition from analogue trunked communication systems to digital trunked communication systems cannot be completed overnight.On the other hand,the newly-added areas with complicated security order,densely-populated areas and newly-established gathering places also require the signal coverage of police private networks.So,the smooth analogue-to-digital transition of wireless private network plays a critical role in the wireless communication of public security.In recent years we witnessed the rapid development of wireless police communication technologies and various targeted construction schemes regarding digital trunked communication have been made in different places across China.However,in the transition from analogue private network trunked communication systems to digital ones,the analogue-to-digital shift,especially the signal coverage in blind areas have become the common problem needs to be solved urgently.This thesis,focusing on the research of analogue-to-digital transition under various modes,has analyzed several transition schemes from analogue wireless private network to digital wireless private network under typical scenarios.Also,by taking references to the analogue-to-digital plan of 350 MHz trunked communication system from the science and technology administration of public security department of China,the general and applicable solutions of analogue-to-digital transition and the blind-area coverage are given here.This thesis analyzes five typical cases in China,and has researched the problems that occur during the analogue-to-digital transition of police wireless private networks: analogue-digital interconnection,frequency reuse,boundary blind-area signal coverage and multi-network convergence as well as analogue-digital interconnection,wireless communication hand-off,overlapping-area interfering under simulcast communication,wireless link and blind-area coverage,and it is verified by being used in the actual project.The solutions to those problems above play a crucial role in the analogue-to-digital transition of trunked communication system.The digitalized command & control for public security,the demand of newly-added private networks,the private-network signal coverage in critical areas and flexible transition of analogue-digital networks can be solved or improved while preserving the existing investment to ensure the rapidness and accuracy of wireless command & control of public security.Under the solutions provided here,the advantages of digital trunked communication system including acoustic code encryption,centralized command and tracking & positioning can also be utilized.The better voice quality,higher frequency use ratio and faster voice delivering speed as well as the introduction of encryption and secondary development functions are able to meet the urgent safety,accuracy and efficiency demands of wireless command & control of public security.