Space and frequency diversity measurements of the 1.7 GHz indoor radio channel using a four-branch receiver

The practical space and frequency diversity performance achievable inside a building at 1.75 GHz under fading conditions due to the motion of a portable terminal and due to the movement of people are investigated. Data are collected using a four-branch dual-frequency envelope receiver positioned throughout one floor of a university building of common construction type. The measurement environment is characterized for large-scale path loss and wall transmission loss. Envelope cross correlations are calculated, and performance of diversity is measured for various frequency separations and antenna spacings which would be applicable given the physical size of portable telephones and data terminals. Two-branch space diversity is directly compared to two-branch frequency diversity and to four-branch hybrid diversity based on simultaneous measurements of each using selection combining. The distributions of correlations and diversity gain at different locations are also investigated. Results indicate that two- and four-branch diversity can be a very effective way to combat signal fading for portable terminals in an indoor radio environment