Key words: VLSI, constellation, architecture, rayleigh fading channel
Abstract:
Diversity is the key solution to obtain efficient channel coding in wireless communications, where the signal is
subject to fading (Rayleigh Fading Channel). For high spectral efficiency, the best solutions used nowadays are
based on QAM constellations of 1-order diversity, associated with a binary code or a trellis coded modulation to
increase the overall diversity. It has been shown that a new class of d-dimensional non-QAM constellations,
named ?-constellations, can bring a d-order diversity without the addition of redundancy. Combined with
classical coding techniques, ?-constellations are very efficient. However, the decoding algorithm is far more
complicated for ?-constellations than for QAM-constellations. A sub-optimal algorithm that allows the decoding
of ?-constellations is proposed. An example of an application for a 4 bits/Hz/s spectral efficiency with a 4-D ?-
constellation is given. The VLSI architecture of the decoder is described. The implementation leads to 72 K
gates, a binary rate of 32 Mbits/s and a BER of 10-3 for a SNR of 14 dB.
Full Paper: Click Here
Authors: Emmanuel Boutillon, Jose Urunuela
Reference: Special issue on VLSI for wireless communication, Wireless Network, p.17-26, ACM, 1998.