On the feasibility of outdoor-to-indoor LTE small cell deployments: Field trial experiments and performance prediction

Small cells offer promising advantages to increase the spectral efficiency of wireless systems, thanks to their small frequency reuse factor. In complement to the macro cellular network, they can provide more uniform Quality of Experience (QoE) across the entire geographical area of interest. This paper focuses on performance of Long Term Evolution (LTE) small cells, taking as reference outdoor small cells deployments providing services to indoor users. The main contribution of the paper is demonstrating the performance benefits of small cells for outdoor to indoor coverage through a set of field trial experiments that were recently conducted on-air at 2.6 GHz. Furthermore, we introduce an analytical three dimensional (3D) performance prediction framework, which we calibrate and validate against field measurements. In particular, this framework can determine detailed performance levels at any point of interest within a building and allows for fast and easy what-if scenarios testing. It can be used to create rules of thumb for deploying small cells, and can be applied to large scale small cell deployments.