Research And Implementation Of PDCP And RLC Layer In LTE-A Terminal System

As a standard 4th Generation mobile communication technology(4G),Long Term Evolution-Advanced(LTE-A)system is an important turning point in the development of wireless communication industry.Compared with the previous generations of mobile communication network,it has the characteristics of high transmission rate,wide coverage,large capacity and high spectrum utilization.With the continuous construction of LTE-A network,the number of LTE-A terminal equipment shows an explosive growth.LTE-A base stations will face much greater pressure of co mmunication.The contents of this thesis rely on the project "Research on Key Technologies of LTE multi UE base station load and capacity test",aimed to develop an instrument which simulates large number of LTE-A terminal equipment.So the capacity and performance of LTE-A base station can be tested.The main target of this thesis is to realize the functions of Packet Data Convergence Protocol(P DCP)layer and Radio Link Control(RLC)layer.These functions are implemented in Q uad-core Digital Signal Process(DSP)TMS320C6670.The functions of PDCP are data transmission,header compression,security and reconstruction.The functions of RLC are segme ntation,concatenation,reordering and retransmission.As to the implementation part,according to the protocol and the actual demands of the project,some functional modules which use the hardware interface provided by multi-core DSP have been designed firstly.The adaptation layer module is responsible for dealing with the cross entity interaction of the primitives.The timer module implements the timing and counting functions of the protocol stack.The trace module and the error processing module are responsible for tracking the protocol stack.Then the interface primitives,states division,transmission processes and naming rules of functions are designed.Finally,function modules of PDCP layer and RLC layer are developed by C language.Some of these functions are chosen as examples to describe procedures of coding.The test part follows the test protocol.A loopback testing method is taken to do a single layer conformance test of PDCP layer and RLC layer through 14 test cases separately.Single layer tests of PDCP and RLC are completed in Code Composer Studio(CCS)and Testing and Test Control Notation version 3(TTCN-3)platform,including the maintenance of sequence number,segmentation,concatenation,status report and retransmission in RLC layer as we ll as encryption and integrity in PDCP layer.And all the test results meet the requirements of the test protocol.