Summary: Differential Space­Time Coding for Frequency­Selective Channels
S. N. Diggavi N. Al­Dhahir A. Stamoulis A. R. Calderbank
AT&T Shannon Laboratory
180 Park Avenue
Florham Park NJ 07932
fsuhas,naofal,as,rcg@research.att.com
Abstract
In this paper we introduce two space­time transmission schemes which allow full­rate and full­diversity non­coherent communications
using two transmit antennas over fading frequency--selective channels. The first scheme operates in the frequency domain where it
combines differential Alamouti space--time block--coding with OFDM. The second scheme operates in the time domain and employs
differential time--reversal space--time block--coding to guarantee blind channel identifiability without the need for temporal oversampling
or multiple receive antennas.
1 Introduction
Since their invention, space--time block codes (STBC) [10] have sparked wide interest as they promise to significantly
increase transmission rates in wireless communications. With N transmit and M receive antennas, over frequency­selective
channels, the total number of channel parameters that needs to be estimated is NM (š + 1), where š is an upper bound
on the order of the underlying finite--impulse--response (FIR) channels. The overhead of frequent re­training coupled with
the increased cost of channel estimation and the degradation of tracking quality in fast time­varying environments make
non­coherent schemes attractive alternatives.
Previous related work includes differential STBC schemes with two [9] or more [7] transmit antennas, group differential

Source: Al-Dhahir, Naofal - Department of Electrical Engineering, University of Texas at Dallas

Collections: Engineering