Communications
UWB-OFDM system architecture has remarkable potential
to be employed for both radar and communication purposes,
with little, if any, changes to hardware. High spectral
efficiency of OFDM signals allows for coding bits or symbols
of data using individual sub-carriers. The receiver side
remains the same as in case of radar - the sub-carrier
composition of the signals is determined via FFT, as shown in
Fig. 1 - which was implemented in MATLAB to simulate
image transmission.
Fig. 8 shows "ideal" image simulated using noiseless an
ossless UWB-OFDM SAR model, as described in th
previous section; it also shows image transmission results fo
noisy AWGN channels with signal-to-noise ratios (SNR) o
approximately 5 dB and -7.5 dB. The data were encoded
using 128 OFDM sub-carriers after the original image wa
epresented as 128x128 pixel array and each pixel's value wa
quantized with 4 bits, thus resulting in 8 KB data vector
When no additional encoding (such as, e.g. QPSK) is used
one sub-carrier will represent one bit of information
Assuming 4x re-transmission rate and 1 Gs/s sampling in th
ransmitter and the receiver, we can calculate total tim
needed for this image reception to be approximately 0.5 ms
mportant assumption made in this portion of the study is ful
synchronization between the platforms. This scenario is no
ikely to occur in realistic environments. Future studies on
synchronization methods between the platforms united int
maging radar network are required.
OFDM signals and system architecture. Authors' goal was to
assess basic functionality of such a system from imaging and
image transmission and reception perspectives.
This goal was achieved via simulation analysis performed
in MATLAB, with the results clearly showing good potential
of UWB-OFDM radar with 1 Gs/s sampling rate to produce
high-resolution imagery and to be employed as an image
communication system. These results may be used in
subsequent experimental study of UWB-OFDM systems, as
planned by the authors.