Deployment Options for Providing Indoor Coverage in High Frequency Bands
Gustav Larson · KTH Publication Database DiVA (KTH Royal Institute of Technology) · 2015
Mobile traffic is expected to grow rapidly over the next few years. This traffic increase will lead to a shortage of available bandwidth in the traditional frequency bands. As a solution to the shortage of bandwidth, the industry has started to look into acquiring additional spectrum to meet the future demands. However, substantial new spectrum can only be made available at higher frequencies than those in use today, where the propagation characteristics are more problematic. This thesis investigates the feasibility of different deployment alternatives for providing indoor coverage at high frequencies (10 GHz to 60 GHz). The required base station density in order to meet six coverage and capacity targets is compared for different frequencies and deployment concepts. Firstly, the deployments are studied in a single building scenario. Secondly, the results from the single building scenario are applied to a city scenario in order to study how a surrounding macro layer affects the indoor performance. In the single building scenario, deployment of outdoor micros were found to be suitable for low and moderate data rate/capacity requirements up to 30 GHz, and high capacity/data rates up to 15 GHz with the use of beamforming. Indoor deployments were required to achieve indoor coverage at 60 GHz and for high data rate/traffic requirements at lower frequencies. Distributed antenna systems were found unsuitable at higher frequencies due to large losses in the coaxial feeder cables. In the city scenario achieving dominance over the macro layer was problematic due to the large beamforming array used by the macro base stations. However, the data rates for the users served by the small cell deployments were found to be similar to the single building case.