Spectral efficiency of dynamic DAS with extreme down-tilt antenna configuration

The current outdoor deployments, dominated by macrocellular layer, inherently lacks the capabilities for supporting the anywhere and anytime services of Beyond 4G (B4G) networks. Hence, new deployment solutions are required that can cost-effectively address the capacity demand of the future and also offer consistently high bit rates and decent quality of service (QoS) throughout the network coverage area. This article looks into an advanced outdoor distributed antenna system (DAS) concept as a potential solution for fulfilling the requirements of 5G era. The investigated DAS solution can dynamically configure itself as a single super microcell or multiple independent small microcells, based on the outdoor traffic conditions. We evaluate the performance of dynamic DAS using two antenna configurations based on; (i) No-tilt (utilizing Omni-directional antenna) and (ii) Extreme tilt (utilizing wide beam directional antenna). Furthermore, the analysis covers the performance evaluation, mainly from an outdoor perspective while taking into account two key performance metrics: coverage and spectral efficiency. The obtained results indicate that the dynamic outdoor DAS concept can offer an efficient and capacity-adaptive solution to provide on-demand outdoor capacity in urban areas. Moreover, the extreme tilt configuration is shown to improve the cell and area spectral efficiency of dynamic DAS, in outdoor dense urban environment, by effectively controlling the inter-cell interference.