The demands for greater capacity and lower transmitted power have historically motivated
research in spatial diversity systems. Diversity techniques have been implemented in many
current systems and have been shown to reduce the transmit power required to maintain
acceptable system performance. Traditionally spatial diversity is based on the transmission and
reception of a single stream of symbols through independent and spatially separated propagation
channels. In more recent developments, space-time coding and array processing techniques use
diversity concepts to resolve multiple independent streams of data and increase the potential
data-rate. This new space-time research investigates the unprecedented ability to simultaneously
transmit separate data streams from many closely-spaced antennas on a common carrier
frequency. The effectiveness of these multi-element arrays in communication systems has been
found to depend on antenna design and specific characteristics of the propagation channels. This
thesis describes an effort to characterize an indoor office environment with respect to these
applications.
Theoretical analyses have demonstrated a relationship between the theoretical capacity of multi-element
array systems with the cross-correlation of spatially separated channels. Historical
measurements have also shown that in the presence of Rayleigh fading, antenna spacing may be
used to control the level of correlation between propagation channels and maximize the diversity
gain, or potential system capacity of a space-time system. Both the design of the antenna arrays
and characteristics of the propagation environment influence a system’s potential capacity.
This thesis describes the construction of a measurement system and the use of this system to
evaluate the capacity gains of multi-element arrays in a wireless communication system. The
presented system is capable of measuring the channel gains between a number of transmitter and
receiver antenna elements and calculating both the cross-correlation between channel gains and
the theoretical system capacity. After a discussion of previous research, the measurement system
and subsequent measurement results are described.
