Research Of Baseband Physical Network Coding Based On FPGA

Physical layer network coding (PNC) is evolved from the network coding(NC). It can combine the Technology of the network coding and the electromagnetic characteristics of the physical layer of wireless networks, that not only can eliminate the mutual interference between the signal caused by electromagnetic waves broadcast features, but also can use this interference to greatly improve the throughput of the network. This makes it a new direction for network coding.This theies studies the physical layer network coding and builds a three-node wireless two-way relay model of physical layer network coding communication system that based on the binary phase shift keying (BPSK) modulation.The communication system model has been simplified and used in the two field programmable gate array (FPGA) development board.In the design, two nodes that exchange information with each other use BPSK way to achieve the modulation of information,and the relay node modulates information by using of binary differential phase shift keying (BDPSK) way. Demodulation of the relay node mapping is processed in accordance with demodulation of the PNC mapping principle that based on the BPSK modulation. The design of carrier synchronization in accordance with the Costas phase-locked loop principle. Bit synchronization is designde based on differential rectification of all-digital phase-locked loop principle. centralized plug-in principle of Barker code to achieve frame synchronization. In Xilinx’s ISE10.1development environment, to design modules by using the Verilog hardware description language,such as the module of frame coding and BPSK modulation of two nodes to exchange information, the module of demodulation mapping and BDPSK modulation of the relay node,carrier synchronization module, bit synchronization module, and the design of the frame synchronization module. Do unit module simulation and system simulation, With Modelsim6.0simulation tools. the design of three-node wireless two-way relay model of physical layer network coding communication system, that based on BPSK modulation is download to Xinlinx company’s two FPGA development board of the Virtex-II Pro chip hardware platform to do system test. And the results are analyzed, According to the system software simulation and hardware test. Simulation and test results show that:both the unit module simulation and overall system simulation are enough to meet the design requirements. In the three-node wireless two-way relay model of physical layer network coding communication system that based on BPSK modulation,the two nodes that exchange information via relay node can correctly implement one time information exchange during two time slots.So we can come to the conclusion that the overall design meet needs.