Communication Node Selection And Key Technology In Cooperative Network

With the continuous development of the mobile communication network,the network capacity and the spectral efficiency are put forward higher require-ments. Meanwhile, in the cellular networks, the distance between the cell edge user and the base station is far, so the performance of such users is severely af-fected. Cooperative relay network can significantly improve the system spectral efficiency and the performance of the cell edge users, and has attracted a lot of attentions of researchers. Thus it is considered as a key technology in the fu-ture mobile communication network. However, there are many nodes in the cooperative relay network, it is worth investigating how to select these nodes effectively to improve the outage performance and the diversity performance of the relay network. Therefore, in view of different relay network structures,this paper puts forward the corresponding selection schemes, and analyses the outage performance of the proposed schemes. In additon, there exist energy-constrained relay nodes in the relay network, and we investigate the outage per-formance of such relay network when energy harvesting technique is adopted at such relay nodes,The innovations and contributions can be summarized as follows:1) In this paper, the relay network is investigated with direct link between the source-destination and two-way traffic. A multi-source multi-relay net-work is considered with one destination and two-way traffic,in which each node works on full-duplex transmission mode to improve the spectral efficiency and the capacity of the relay network. Unlike the existing schemes, the direct link from the source to the destination is taken into consideration. A joint source-relay selection scheme is proposed. A new and achievable outage probability is derived for the proposed scheme, which includes the influence of the residual self-interference. Next, a simple asymptotic expression with high signal-to-noise ratio approximation is derived, and the diversity order of the system is analyzed. Meanwhile, the impact of the direct link on diversity order is also be analyzed.2) In this paper, the Tx/Rx mode of the two antennas in each relay can be adaptively determined based on the relaying link condition. As the channel link from the source node to the receive antenna of the relay or from the transmit antenna of the relay to the destination falls into deep fading, which will im-pair the performance of the relay network. Therefore, we investigate that the Tx/Rx mode of two antennas in each relay is adaptively determined based on the instaneous signal-to-interference-plus-noise ratio of the relaying links. The relay network consists of one source node, multiple full-duplex relays and mul-tiple destination nodes. In the source node, multiple antennas are configured and beamforming technique is employed to improve the performance of the system. In addition, each relay is equipped with two antennas, one for receiv-ing, and the other for transmitting. Joint destination-relay selection and antenna mode selection scheme for full-duplex relay network is proposed. In addition,the cumulative distribution functions of the direct link signal-to-noise ratio and the relaying link signal-to-interference-plus-nosie ratio are derived. Based on the cumulative distribution functions, the closed-form outage probability and the simple asymptotic expressions are derived. Meanwhile, the diversity order of the relay network is also analyzed.3) In this paper, a energy-constrained relay network is investigated, and the outage performance of such relay network is provided. In addition, the power splitting factor at each relay node is optimized to minimize the outage perfor-mance. As the energy-constrained relay nodes do not have the energy supply,thus the energy harvesting technique should be adopted at the relay node. An energy-harvesting multiple input multiple output relay network is investigated,in which multiple single-antenna relay nodes are deployed between the multi-ple antenna source and single antenna destination. The relay node is energy-constrained and works on half-duplex, thus the energy harvesting technique is adopted at each relay node to prolong the lifetime of the relay network. Di-rect link between the source node and the destination node exists and can be a potential way to convey information. Meanwhile, the outage performance of the relay network is analyzed, and the diversity order of the relay network is provided. In addition, the optimal power splitting factor at each relay node is derived to minimize the outage performance.