An experimental evaluation on the performance of polarization diversity scheme on TACS versus space diversity scheme

• Main Author: Sanchez, Harry S.
• Format: text
• Published: Animo Repository 1997
• Subjects: Mobile communication systems; Radio > Receivers and reception > Diversity systems; Antennas (Electronics); Radio waves > Polarization; Cellular radio; Digital Communications and Networking; Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/1866
• Institution: De La Salle University

The traditional method for antenna diversity is based on the use of two Rx (receiving) antennae, preferably horizontally separated (space diversity). It has been in use in the cellular industry since the time when mobile telephony has started. However, the increased use of handheld cellular telephones and the need for many cell sites for the widest coverage areas make it possible to use polarization diversity because it reduces the need for a number of antenna units as well as the required separation distances between the Rx antennae.Insofar as tests of polarization diversity is concerned, measurements were conducted in GSM and DCS 1800 digital systems. Therefore, it was convened that field experiment be conducted interrelated to the effects of polarization diversity into the analog systems of TACS.This paper describes the set-up and configuration of the field experiment and eventually presents the results of an experimental measurement and statistics evaluation in using a di-polarized antenna for a polarization diversity technique and two separate vertically-polarized antennae for a space diversity scheme. Measurements made were drive (inside-car-use) tests and walk tests. The latter were conducted in three cases: indoor and outdoor, with and without line-of-site, and within the major lobe coverage area and a little broad side to the major lobe coverage area of the base station. In each of the tests, the characteristics of the signals received by the di-polarized antenna and the two branches vertically-polarized antennae in the base station were measured relative to the different orientation of the mobile phone set at 0 degree, 50 degrees, and 90 degrees to the vertical plane. Furthermore, the factors considered in evaluating polarization diversity into the system have been calculated using the formulae in the literature. These are cross correlation coefficient, cross polarization discrimination (XPD), and diversity gain.Finally, summary of contrast and comparison between the performance of the antennae relative to space and polarization diversity schemes, conclusion, and recommendation based from the figures taken from the measurements are presented.