Research And Implementation Of Active Interference Cancellation Method For MB-OFDM UWB

ABSTRACT:Active Interference Cancellation (AIC) is an physical layer algorithm used to suppress interference for MB-OFDM Ultra wide-band (MB-OFDM UWB)systems. This algorithm take advantage of OFDM technology to create dynamic notch on spectrum according to the situation of current interference, so as to avoid the impact on UWB and the other narrow band systems who shares the spectrum with UWB systems. Because the interference has always been the problem on the development of UWB, AIC algorithm gains a lot of attention after proposed. AIC algorithm has good performance and flexibility, but it is hard to implement the algorithm on hardware because of the inverse of non-square matrix part of AIC is too complex and difficult for hardware calculation, and it plant an limitation for AIC algorithm to achieve the actual effects. So, it is important and meaningful to solve the implementation problem of AIC.This article first introduces the OFDM communication system and AIC theory, describes the theoretical foundation for AIC to reschedule the OFDM data sub-carriers and uses the develop tools(System Generator) to design the architecture and analyze the algorithm. We simplify the algorithm according to the feature of AIC, and propose pre-operating and real-time two kinds of AIC hardware implement scheme. The pre-operating one is to simplify several unnecessary steps which is related to the algorithm feature and interference condition; The real-time one uses float-point way to calculate the inverse of matrix and keep the accuracy from many aspects. The real-time scheme can be divided into two kinds of design:AIC based on 2 X 2 matrix inverse and AIC based on 4 X 4 matrix inverse. All modules are designed by System Generator with Xilinx library and IP cores and the whole design can be connect with Verilog HDL module smoothly.Finally, we perform the simulation for all three designed modules with Matlab and Simulink which is band to System Generator. We develop the executable hardware programs and verify the hardware processing result with related instrument and Chipsocpe. After compared the hardware result with simulation one, the conclusion can be draw:the modified AIC hardware implementation scheme can create the proper notch on spectrum which meets the requirement of AIC algorithm.