Energy-efficient traffic offloading in Macro-Pico networks

With the exponentially increasing traffic demand in future mobile networks, energy consumption becomes a significant challenge of information and communication industry. In this regard, deploying small, low power base stations alongside traditional sites to offload macro base station (BS) is expected to be a promising method in reducing the total energy consumption of cellular networks. In this paper, we propose a traffic offloading scheme from macro BS to low Power Nodes (LPNs), such as pico stations and explore the energy efficiency gains. In this scheme, we first determine the optimal target LPNs of traffic offloading in Macro-Pico networks, aiming at improving energy efficiency (EE). We propose two offloading algorithms, called Traffic Offloading (TO) algorithm and Traffic Offloading based on Frequency Reuse (TOFFR) algorithm. TO algorithm takes into account the Reference Signal Receive Power (RSRP) of uses and traffic load of cells, and thus determines the target pico for offloading traffic. To further improve system energy efficiency and the throughput of users at the edge of cells, we design TOFFR algorithm by combining TO algorithm with frequency reuse. We conduct experiments based on system level simulation to examine the effectiveness of our proposed algorithms and numerical results show that the proposed algorithms can achieve considerable energy efficiency gains when traffic offloading is implemented and TOFFR algorithm can further improve system energy efficiency with trivial complexity cost.