Theoretical study and performance evaluation of macro‐assisted data‐only carrier for next generation 5G system

Summary With the explosive growth of high‐data rate multimedia services and machine‐to‐machine (M2M) type communications, numerous small cells will be densely deployed in future fifth generation wireless network, resulting in serious interference, intolerable delay, and huge handover failure. Massive access M2M services, with low‐rate high‐frequency requests, will also generate much signaling overhead costs and cause enormous waste of system resources. In the Third Generation Partnership Project, the split of control and user (C/U) planes is perceived as one of the most promising methods for small cell enhancement to address these challenges. In this article, a new C/U split architecture of data‐only carrier (DoC) system is analyzed comprehensively from various aspects, such as overhead costs, coverage probability, spectral efficiency, and energy efficiency for the first time. Based on the model of stochastic geometry, the influences of density and power of small cell and cell range expansion factors are all taken into account to compare the DoC architecture with the baseline long‐term evolution (LTE) system. Numerical results show that the DoC system can greatly reduce the overhead costs and help to achieve higher throughput gain and better coverage performance over the conventional LTE system. Copyright © 2015 John Wiley & Sons, Ltd. Based on the concept of the split of control plane and user plane, a macro‐assisted pure data small cell architecture is proposed as DoC (data‐only carrier) to enhance the small cell discovery, handover, and sleep procedures toward a much ‘greener’, ‘softer’, and ‘user equipment‐centric’ network. Analyzed by stochastic geometry theory, the new DoC and the current long‐term evolution (LTE) systems are theoretically analyzed in detail from the aspects of co‐channel and hetero‐channel, the density and power of small cells, the empty‐load probability, and the cell‐specific reference signal bias. It is shown that DoC can achieve above 45.5% spectral efficiency gain and 15.2% coverage gain toward current LTE system under 50% empty‐load probability of ultra‐dense network.