On the In-Building Performance and Feasibility of LTE Small Cells with Beamforming Capabilities

We disseminate a set of small cells field trial experiments conducted at 2.6 GHz and focused on coverage/capacity within an office building. LTE pico cells deployed in indoor as well as LTE small cells deployed in outdoor are considered. The latter relies on small emission power levels coupled with intelligent ways of generating transmission beams with various directivity levels by means of adaptive antenna arrays. We show through measurements that the antenna directivity is well preserved within a building which could be exploited to boost capacity by activating multiple beams with narrow horizontal beams for outdoor-to-indoor coverage. Using low power small cells with directive antennas one can establish high data rates, in a controllable way, for a large area of the office building. Furthermore, we calibrate and validate an analytical three dimensional (3D) performance prediction framework against field measurements and use it to quantify the angular dispersion which indicates the preservation of the antenna directivity.