Architecture exploration, development and teaching platform for Orthogonal Frequency Division Multiplexing (OFDM) systems

Abstract

The objective of the presented work is to have a complete system level Orthogonal Frequency Division Multiplexing development platform where students both undergraduate and graduate can use it to explore and identify the different processing blocks available on modern communications systems. The platform will allow monitoring the inputs and outputs of every block to observe the signals as well as to be able to substitute each block by their own implementation. This could be done using a high level language such as Matlab/Simulink and C/C++, or the block can be substituted by a Hardware Description Language (HDL) such as: automatic Simulink to HDL, automatic C/C++ to HDL or directly by a HDL implementation. In addition, the concept of Hardware in the loop is introduced where the block is actually run on field programmable gate array (FPGA) hardware. The platform allows the use of the FPGA as a hardware accelerator or coprocessor. Different tradeoffs in algorithm hardware implementations can be explored such as: signal throughput, floating to fixed point conversion, hardware resources, silicon area estimates, power consumption, maximum operating frequency, and signal to quantization noise ratio.

Performance Analysis of OFDM Channel Estimation Under IQ Imbalance

“…At the receiver, the process was reversed as the Discrete Fourier Transform (DFT) block was applied, and the estimates of the QAM symbols were obtained. This information was mapped back into a series of bits to produce the output bit stream [17]. The block diagram of an OFDM system was shown in Fig.…”

Evaluation of Ber Performance of FFT-Ofdm for Wireless Communication Networks

“…But since OFDM takes one-word carrier and spreads it over several smaller carriers, so even if you have one fading in one specific frequency the station still has other useful channels, which can still convey the information. So instead of numerous adjacent symbols being destroyed, only some symbols are little bit distorted, spectral overlapping among sub-carriers is allowing improved spectral efficiency and used of steep band pass filter is eliminated [9]. In OFDM transmission where subcarriers are orthogonal to each other in frequency domain, it also distributes data over many numbers of carriers that are spread out at precise frequencies.…”