Research And Implementation Of PDCP Layer Protocol Of TD-LTE Broadband Multimedia Trunking System

The limitation of narrow-band trunking technology make it unable to adapt to the current mobile Internet era with multi-service,multi-user,and high-rate.Broadband wireless trunking systems with independent intellectual property rights have emerged in China.At the same time,"The B-Trun C System Interface Technical Requirements(Phase 1)Air Interface" was recommended by the ITU as an international standard,which means that China holds a world-leading level in the field of Broadband Trunking communications.The TD-LTE Broadband Multimedia Trunking system is based on the B-Trun C protocol standard.The trunking communication is mainly targeted at government,railway,water conservancy and other industry users,so the safety and stability are the primary goals.As one of the main components in the wireless interface protocol stack of the trunking system,the PDCP protocol provides functions such as data encryption,integrity protection,and header compression.It means that the implementation of this protocol can improve the security and stability of the system to some extent.For the TD-LTE Broadband Multimedia Trunking System PDCP layer protocol software design and development process,the main contributions of this paper are as follows:(1)Introduced the development status of the trunking system and discussed the significance of researching TD-LTE Broadband Multimedia System.At the same time?The TD-LTE Broadband Multimedia Trunking System framework is introduced and the PDCP layer protocol framework and functional characteristics are further analyzed in detail.(2)Discussed the similarities and differences between the trunking system and the TD-LTE system PDCP layer protocol in terms of functions and data processing flow.Researched and analyzed the design and implementation scheme of PDCP protocol software in the existing TD-LTE system.According to the research results,the research idea of Broadband Trunking PDCP protocol software was proposed.At the same time,the key factors that need to be considered in the software design of the protocol are analyzed.(3)Combining with actual needs,the overall framework design of the terminal side and base station side of the TD-LTE Broadband Multimedia Trunking System PDCP layer protocol software is proposed,including interface design and functional module partitioning.Then,the specific implementation ofthe configuration module,the scheduling module,the add/delete PDCP header sub-module and the sequence number sub-module in the entity module is completed.In the specific implementation process,the inter-process communication method is used to complete the protocol software interaction with the upper layer protocol,use the NETLINK method to interact with the lower layer and kernel module.Use memory pools,queues,lists,etc.to complete memory management.(4)Tests of protocol software function modules have been performed to verify the correctness of functions design.The overall function and performance of the PDCP protocol software has been tested,and the correctness and rationality of the module function division and flow design have been proved.