Energy efficiency of Heterogeneous cellular Network(HetNet)has attracted wide attention in recent years. However,researches on the energy efficiency of macro base stations using non-Poisson process are not enough. To solve this problem,the energy efficiency of the two-tier HetNet was investigated,in which the deployment of macro base stations was modeled by β-Ginibre Point Process( β-GPP). Firstly,a simple approximation method was used to analyze the Signal to Interference Ratio(SIR)distribution in two-tier HetNet,then the coverage probability,the average achievable throughput and the energy efficiency of the system were derived. Finally,an energy efficiency optimization algorithm was proposed to find the optimal transmitting power of pico base station,maximizing the energy efficiency. The simulation results show that when β=1,the distribution density of macro base station is 2×10 ^-4 m ^-2,and the distribution density of pico base station is 2 times of that of macro base station,the proposed energy efficiency optimization scheme can improve the system energy efficiency by about 20%. The experimental results verify the accuracy of the theoretical analysis and the effectiveness of the proposed energy efficiency optimization algorithm.

To solve the problem of low Energy Efficiency (EE) of relay assisted cellular networks where the Macro Base Station (MBS) was equipped with a single-antenna, the downlink transmission of multi-antenna relay-assisted cellular networks were considered, meanwhile, a strategic sleep scheme was proposed. Firstly, according to whether the number of users serviced by the relay exceeds a given threshold, the relay's working mode was dynamically adjusted. And then the coverage probabilities and mean achievable rates of MBS to user (UE), MBS to Relay Station (RS), RS to UE links were deduced. Finally, the energy efficiency of the system was derived based on the power consumption per unit area and the reachable rate per unit area. The simulation results show that when the density of MBS is 2×10 ^-5m ^-2, the energy efficiency of the multi-antenna network with strategic sleep scheme is about 5.6% higher than that of the cellular network with non-sleeping strategy; the system energy efficiency of MBS equipped with multiple antennas is 30% high than without sleep strategy scheme with single antenna. Experimental results indicate that the multi-antenna relay-assisted cellular network with sleep strategy scheme has higher energy efficiency than the single-antenna relay-assisted cellular network.