Propagation within buildings at 2, 5, 17 and 60 GHz for wireless broadband data communications

• Main Author: Nobles, P.
• Published: Swansea University 2000
• Subjects: 621.3
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638335

Wireless communication is the world's fastest growing industry. By 2010 over one-half of all computer network connections will be wireless. A major percentage of these will be connections that originate and/or terminate within a building. For wireless networking to appear transparent to the user a resilient and reliable radio link must be provided. Such a link must overcome the distortion and interference of the indoor radio propagation environment. For the successful design of wireless broadband systems a thorough knowledge and understanding of the indoor radio propagation channel is required. This thesis presents the finding of an extensive investigation into indoor propagation at the frequency bands allocated for wireless data communication networks. Measurements of the complex frequency response of the indoor channel using a vector network analyser are reported. Values for rms delay spread at 2, 5 and 17GHz and received power levels at 2, 5, 17 and 60GHz are obtained. Nonparametric statistical analysis is applied to the rms delay spread values to confirm observed trends in the data. Rms delay spread was found to decrease with increasing frequency between the three bands measured, but increase with transmitter-receiver separation and obstruction of the direct path by walls and metal furniture. Path loss was evaluated by measuring the received power within a small room, a larger room and across floors with different wall types. Line-of-sight and obstructed locations were considered for two antenna heights. Within a room, the line-of-sight path loss is shown to be less than predicted for free-space. The received power results are used to validate a model for path loss within a building. An important aspect of the model is a coefficient which is added to the free-space path loss values and takes into account raised power levels due to the reverberation effect caused by multipath reflections.