Design And Implementation Of MCPTT Terminal Software

The Mission Critical Push To Talk(MCPTT)is the latest generation of trunking communication standard released by 3GPP in March 2016.It is an all-IP application layer service running on LTE networks.MCPTT over LTE service supports an enhanced PTT service,suitable for mission critical scenarios.MCPTT service supports authentication,group affiliation,group management,group call,private call,emergency call,flow control,location reporting and other functions.MCPTT combines many advantages such as large bandwidth,low latency and enables easy scaling to large scale networks.Compared with the existing technologies,MCPTT has considerable advantages and deserves further research and development.This paper first summarizes the development of trunking communication system and the existing Po C solution of trunking communication system.Then analyzes the functional requirements,system architecture and functional model of MCPTT.According to the functional requirements of MCPTT,the overall architecture of MCPTT terminal software is designed.The signaling processing method is designed in detail,and a new method for compressing MCPTT signaling on Carrier Aggregated broadband system is proposed.After that,it elaborates the design and implementation of login related services,voice services and geographical location services.In the related services of login,the functions of authentication,login and group affiliation are designed and implemented.In the voice service,the functions of manual private call,auto private call,group call and priority call are designed and implemented.The emphasis is on the design of voice service state machine and the priority queues is used to ensure the order of state switching and signaling reception.In the geographical location services,the geographical location configuration and reporting of geographical location in two ways are designed and implemented.An algorithm is designed to determine if a MCPTT terminal is within the Geo-fencing.Finally,the paper has carried on the function test to MCPTT terminal software.The test results meet the requirements of 3GPP standard.