Non Contiguous Orthogonal Frequency Division Multiplexing

Home Project Description Team Member(s) Winlab summer project homepage

Welcome..!!!!!!.This is the home page of the Non Contiguous Orthogonal Frequency division multiplexing( NC-OFDM )project.

Cognitive radio is one of the most important research areas at Winlab. A part of this research involves in studying Dynamic Spectrum Access techniques employed to enable use of the White space in communications. My focus of this research is to see whether LabVIEW RT and FPGA is a feasible and efficient platform to perform spectrum sensing and transmission of signals in white space. Non Contiguous OFDM is one of the techniques to employ Dynamic Spectrum Access. In simple terms, NC OFDM is normal OFDM with a mask. The mask is just as string of 1s and 0s whose size depends on the frequency sensing range of the Cognitive Radio. A bit in the mask indicates the presence or absence of a carrier. In NC OFDM we suppress the carriers which interfere with the primary transmission thereby enabling efficient use of the spectrum. For this summer, my aim would be to implement an NC OFDM transceiver on the NI PXIe8133 setup at CORE 532.


My seniors who have already worked on this project before have developed the NC OFDM system on the USRP2. The USRP2 is a good platform for development of spectrum sensing applications but it is slightly complex and requires knowledge and understanding of scripting languages like Python. Debugging also becomes a problem if the signal processing blocks are not understood correctly. The LabVIEW programming language employs a datapath model for coding rather than a command based approach which is employed by C, C++, MATLAB etc. Programming in LabVIEW is easy once the programmer gets used to the block diagram approach. Through implementation of the NC- OFDM transceiver, I will be able to draw a comparison between using LabVIEW RT and USRP2.