Space-time modems for wireless personal communications

Abstract

This article reviews space-time modem technology for mobile radio applications. We begin with motivations for the use of space-time modems and then brie y discuss the challenges posed by wireless propagation. Next, we develop a signal model for the wireless environment. Channel estimation, equalization, and ltering techniques for space-time modems in the forward and reverse links are then discussed. Finally we review applications of space-time modems to cellular systems and discuss industry trends.

Great Expectations: The Value of Spatial Diversity in Wireless Networks

“…When multiple independent receive antennas are available, additional receive diversity gains can be realized by combining the outputs of these antenna using spatiotemporal processing (see, e.g., [201], [202], and references therein).…”

Wireless bandwidth in the making

“…Since each mobile sees a different channel to the base station, it is beneficial to jointly adapt the receiver in the space domain and in the time domain [13], using multidimensional generalizations of classical scalar single-user linear channel equalization techniques.…”

A simulation study on space-time equalization for mobile broadband communication in an industrial indoor environment

“…This means, each receiver channel possesses a number of equalizer taps that are jointly adapted during the training phase, and the output signals of all equalizers are summed to form the signal for the detection of the data symbols. The recursive least squares (RLS) algorithm has been used for the adaptation, which minimizes the mean square error (MMSE criterion) between the output signal of the equalizer and the training sequence [3]. It is especially suitable for mobile communication applications because of its fast convergence [1].…”

“…This paper investigates the potential of a particular implementation of an adaptive antenna, an MMSE space-time equalizer [3], for a wireless LAN system in an industrial environment. The system parameters have been chosen similar to the HIPERLAN/1 standard of ETSI [2] for HIgh PERformance Radio LAN's that employs a single-carrier TDMA transmission scheme with a symbol rate of about 24 Msym/s.…”