|
 |
Space-time coded OFDM for high data-rate wireless communication over wideband channels
Written by:
Dakshi Agrawal,
Vahid Tarokh,
Ayman Naguib,
and
Nambi Seshadri.
Citation:
Proceedings of IEEE Vehicular Technology Conference, 1998, pages
2232-2236, 1998.
Copyright © (1998) by IEEE. Permission to make digital or hard
copies of part or all of this work for personal or classroom use is
granted without fee provided that copies are not made or distributed
for profit. To copy otherwise, to republish, to post on servers, or to
redistribute to lists, requires prior specific permission and/or a fee.
Abstract:
There has been an increasing interest in providing high data-rate
services such as video-conferencing, multimedia Internet access and
wide area network over wideband wireless channels. Wideband wireless
channels available in the PCS band (2 GHz) have been envisioned to be
used by mobile (high Doppler) and stationary (low Doppler) units in a
variety of delay spread profiles. This is a challenging task, given the
limited link budget and severity of wireless environment, and calls for
the development of novel robust bandwidth efficient techniques which
work reliably at low SNRs. To this end, we design a space-time coded
orthogonal frequency division multiplexing (OFDM) modulated physical
layer. This combines coding and modulation. Space-time codes were
previously proposed for narrowband wireless channels. These codes have
high spectral efficiency and operate at very low SNR (within 2-3 dB
of the capacity). On the other hand, OFDM has matured as a modulation
scheme for wideband channels. We combine these two in a natural manner
and propose a system achieving data rates of 1.5-3 Mbps over a 1 MHz
bandwidth channel. This system requires 18-23 dB (resp. 9-14 dB) receive
SNR at a frame error probability of 10-2 with two transmit and one receive
antennas (resp. two transmit and two receive antennas). As space-time
coding does not require any form of interleaving, the proposed system
is attractive for delay-sensitive applications.
|
|
United States
