Transmission Scheme Of 3G Access Networking Base On ATM Inverse Multiplexing (IMA)

In order to meet the IP-based requirements of 3G networks.PTN technology will be the main carrying technique for 3G wireless access network.The IMA technology defines a methodology to provide inverse multiplexing of a high-speed ATM cell stream over multiple low-speed physical links and to retrieve the original stream at the far-end from these physical links.IMA technology break through the limit of single physical's rate and improve the bandwidth utilization.Therefore.IMA is widely used in 3G wireless access network.In order to fully utilize the advantage of IMA,PTN equipment need to support the IMA function which is used to communicate with Node B.Based on the current situation of 3G wireless access network and the future development trend,this thesis develop a PTN equipment which support IMA.Chapters 1 of this thesis introduces the development status of 3G wireless access network,lists several carrying technology and compare among them.Then, The networking solutions based on PTN is proposed in order to meet the IP-based requirements.Chapter 2 give an account of the IMA protocol which is the theoretical basis of this thesis,including IMA frame,IMA Control Protcol(ICP) Cell,IDCC scheduler,IMA Group State Machine,Link State Machine and so on.Chapter 3 firstly gives the system's hardware design,including clock allocation,power allocation and device selection.And then the overall logic design of FPGA is given,which includes module division and function refinement.In the whole development of this system,I am mainly responsible for the design of Transmit IMA Processor(TIMA) and SOPC system in FPGA,which will be described deeply in Chapter 4 and Charpter 5 respectively.Chapter 4 accomplish the design of Transmit IMA Processor(TIMA),which is responsible for the transmit IMA function.TIMA distributes the cells arriving from the ATM layer to several physical links and inserts ICP cells,filler cells among ATM cells to create IMA frame as required by the IMA protocol,and then align the transmission of the IMA frame on the links within the same group.Chapter 5 designs an SOPC system base on NIOSⅡprocessor.NIOSⅡprocessor is applied to achieve the following software:Configuring the IMA parameters,Operating the IMA Group State Machie(GSM),Operating the Link State Machine(LSM). Choosing NIOS II instead of machine state circuit can save much logic resource for FPGA.In Chapter 6,a testbench is written in order to verify the function of TIMA.And then,the whole system is debugged on board.The debugging result show that the system designed can transmit and receive cells in accordance with the requirement of the IMA protocol correctly.