Design And Implementation Of PDCP Layer And RLC Layer In LET-A Pro Test Terminal System

LTE-A Pro,as a further evolution of Long Term Evolution Advanced(LTE-A)system and accommodation of NB-IoT(Narrow Band Internet of Things)system,will be tested and investigated against current mobile communications.The development of the network plays an important role.In addition to the currently widely used mobile terminal devices,with the rapid development of narrow-band Internet of Things,the number of terminals connected to the base station will increase exponentially.In order to meet the access requirements of the NB-IoT and the requirements for using the LTE-A system at the same time,a multi-terminal test instrument needs to be developed to test the anti-pressure capability of the base station to meet the needs of use.In the wireless air interface,a protocol is required to regulate the communication between the network and the terminal.Testing of the LTE-A Pro system terminal protocol stack facilitates the development of the LTE-A Pro technology and products.This dissertation focuses on the PDCP(Packet Data Convergence Protocol)and RLC(Radio Link Control)of the system terminal protocol stack and develops by CCSv5.5 software based on the Digital Signal Processor(DSP).The development of the protocol stack is tested on the platform of the digital signal processor.According to the requirements of the 3GPP communication protocol R13,the functional codes of the PDCP layer and the RLC layer are designed by C language,including the PDCP layer header compression,encryption and integrity protection,and the RLC layer segmentation,concatenation,and reordering.At the same time,according to the requirement analysis,the PDCP layer and the RLC layer are divided into states.The process and state transition mechanism of each state are designed.Besides,interface primitives for inter-layer communication,queues for polling,and processing functions for state machines must be designed to implement inter-layer communications and state machine operations.Finally,a test case is written through the simulation environment of CCS,and a single-layer test is performed on PDCP and RLC to verify the correctness of the function module including the performance testing of the RLC layer segmentation cascade,ARQ(Automatic Repeat Request),status report triggering and generation and PDCP layer security.And this article will test the conformance between Layer 1,Layer 2,and Layer 3 of the protocol stack on the DSP C6670 platform.Finally,experimental test results verify that the protocol test terminal system designed in this paper can achieve the related functions of RLC layer and PDCP layer well and meet the agreement consistency requirements.