Virtual Cells versus Small Cells for In-Building Radio Planning

The emergence of mobile broadband technology provides a valuable service for users to transfer media content, surf the internet, and stream video on their mobile. Higher datarate capability depends on a strong signal from a base station and capacity from the network. 70-90% of wireless high data-rate demand is located inside buildings. A traditional macro base stations thin capacity blanket is insufficient to deal with high data rate in-building users because of the poor signal penetration inside buildings and subsequently lower user link budget. The lower link budget of the in-building users creates a higher battery drain on the handsets. A dedicated wireless system is often installed inside the building or close to the building to address the poor outdoor-to-indoor propagation property of an in-building environment. Small Cells and Distributed Antenna System (DAS) are preferred deployment options for optimal coverage and capacity requirements. A unique approach is a Virtual Cell, which is an Intelligent DAS (IDAS) with capacity routing capability. A Virtual Cell can assign capacity on demand and improve the link budget of the user. In this paper, Small Cell and Virtual Cell performances are compared in an LTE downlink context. It will show that a Virtual Cell has higher usable capacity than a Small Cell with no inter-cell resource block coordination. In addition, the throughput data rates of the two systems converge in hot spots. The Virtual Cell has a capacity scalability since all the Base Station resources are centralized.