Resource Reuse Schemes Based On The Guard-band Of Satellite System

Because of the scarcity of spectrum resource, 5G technology might be allocated near to Broadcast Satellite System (BSS) in the future. Since the weak received signal suffers from the large path loss from the out-space to the earth, the BSS is vulnerable to the adjacent channel interference.Therefore, it is important to investigate the co-existence between BSS and the adjacent channel interference and then adopt theguard-band of BSS.Furthermore, we propose the resource allocation schemes to maximize the capacity of BSS with the existence of the guard-band.We organize the paper in the following:Firstly, we accomplish the system-level simulation of the co-existence of BSS and LTE system. The results show that the BSS receivers suffer from the interference of the LTE system. The LTE system interferes almost 100% BSS receivers. Therefore, it is necessary to utilize the guard-band for BSS to improve the performance of BSS. Meanwhile, because the out-of-band spectrum emission mask in 3GPP standard is more relax than other protocol, the out-of-band spectrum emission mask of the terminals must be analyzed to correspond with the practical statement of the network. We build the model of the out-of-band spectrum emission mask and simulate the LTE terminals and BSS. Although the interference is degraded through the reduction of the power spectrum of out band and adopting better receiving filter, the performance of the methods above is limited. Thus, it is necessary to set the guard-band to avoid the interference to BSS.Then we propose a new resource allocation scheme, which can maximize the throughput of the whole system with the limited interference to BSS. We simulate both the sub-carrier allocation and power allocation.Moreover, to guarantee the fairness between different users and different business types, we adopt the proportional fairness criterion and logistic criterion. Because the weak received signals are hard to detect, any kinds of the random variables will introduce uncertain interference to BSS. Thus,we also take into account the Gaussian distributed channel estimation error in the simulation.Thirdly, we propose another reuse scheme of frequency resource based on BSS guard-band. Moreover, we introduce a random access scheme to reduce the collision rate (CR) caused by the improving LTE terminals under NBIoT scenarios. Compared with the original random access scheme, the new strategy we propose uses two preambles to avoid the collision. The CR of our strategy is at least one over sixty-four lower than the previous schemes theoretically. The final system level simulation indicates that our method reduces the CR dramatically and improve the speed of terminals.In the last, we summarize the whole papers and further research is also considered.