Control data separation and its implications on backhaul networks

As soon as 2020, network densification will be the dominant theme to support enormous capacity and massive connectivity. However, such deployment scenarios raise several challenges and they impose new constraints. In particular, signalling load, mobility management and energy efficiency will become critical considerations in the fifth generation (5G) era. These aspects suggest a paradigm shift towards a signalling and energy conscious radio access network (RAN) architecture with intelligent mobility management. In this direction, the conventional RAN design imposes several constraints due to the tight coupling between the control plane (CP) and the data plane (DP). Recently, a futuristic RAN architecture with CP/DP separation has been proposed to overcome these constraints. In this chapter, we discuss limitations of the conventional RAN architecture and present the control/data separation architecture (CDSA) as a promising solution. In addition, we identify the impact of the CDSA on the backhaul network. An analytical framework is developed to model the backhaul latency of the CDSA, and a densification limit under latency constraints is derived. Furthermore, the impact of the backhaul technology on the CDSA energy saving gains is discussed and an advanced non-direct backhaul mechanism is presented.