DAS, Uncoordinated Femto and Joint Scheduling Systems for In-Building Wireless Solutions

Small cells are popular deployment options for coverage holes and capacity hotspot areas. Due to the poor outdoor-to-indoor propagation property of in-building environment, a dedicated wireless system installed inside the building is often preferred for providing indoor users high-data-rate services. Distributed antenna systems and Femto cells are cost-efficient techniques for this application. In this paper, their performance is evaluated in an LTE downlink context along with a proposed joint scheduling system, which maximizes the supported number of users under a QoS constraint. The selection of the enterprise building model includes a general office building model described in the WINNER II project and a site-specific office building with large scale path-loss values retrieved from measurements. Results show superior performance of the Femto system compared to DAS in providing high-data-rate services in most cases with a quality-guaranteed scheduler, while the centralized joint scheduling system gives the best performance. The centralized scheme can also help improve the system robustness in obtaining high performance even in the situation where access points are placed non-optimally.