On the Guard Period Design in 5G TDD Wide Area

Achieving the trade-off between coverage, ultra-low latency and capacity is a major challenge for a 5th Generation (5G) wide area concept, especially when operating in Time Division Duplex (TDD) mode. In this paper, we focus on the design of the Guard Period (GP) which is needed to accommodate the transition between downlink (DL) and uplink (UL) transmissions in a 5G TDD wide area system operating at below 6 GHz carrier frequencies. The necessity of serving cell edge users with long propagation delays while coping with latency constraints may lead to a large GP overhead, thus reducing the resource utilization in the cell. We propose a distance-dependent scheduling technique which is meant at reducing the GP overhead while ensuring sufficient coverage. Numerical analysis shows the benefits of the proposed techniques in terms of available radio resources, especially for very large cells operating with short frames.