Orthogonal frequency-division multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies. OLYMP Engineering LLC has developed Orthogonal Frequency-Division Multiplexing (OFDM) Library for FPGA. OFDM is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. OFDM works by splitting the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver.
The OFDM transmitter consists of 8 main parts, including data acquisition, modulation, creating OFDM symbols, GPS synchronization etc. By using NI adapter module for FlexRIO you can transmit data from any external source.
The OFDM receiver consists of 11 main parts, including receive data from RF analyzer, decimation and center frequency estimation, packet detection using autocorrelation method, Fourier transform, demodulation, etc.
With the addition of NI VST module it is possible to add additional features such as: Reed-Solomon coding and decoding, Convolution coding and Viterbi decoding, Interleaving and deinterleaving.
The advantages of OFDM:
Full implementation |
on NI FPGA |
Full duplex Tx/Rx |
on 2 FPGAs |
Bandwidth |
up to 26 MHz |
Frequency hopping |
up to 400 hop/s (requires GPS synchronized pps) |
TDMA implementation |
for bandwidth efficient usage |
Supported modulation schemes |
PSK, QAM |
Supported subcarriers |
64, 128, 256, 512, 1024 and 2048 |
Supported data throughput |
16 Mb for BPSK |