Researches On Wireless Energy Harvesting In Interference Alignment Networks

Since wireless network nodes can harvest the energy from surrounding environment, based on the Energy Harvested network, which can overcome the bottleneck of constrained energy in traditional wireless network. SWIPT( Simultaneous Wireless Information and Power Transfer, SWIPT) is a new technology which utilizes RF(Radio Frequency)not only in transferring information but also the power to deal with the problem in wireless nodes without fix power supply. In the conventional view, interference is an inevitable problem that must be solved in the wireless communication system design. But for the Energy Harvesting—the interference is a huge energy source.Therefore,in the interference network of Energy Harvesting,only considering the interference elimination is a large waste for the resource. In order to realize the interference arrangement and Energy Harvesting at the same time. The Interference Alignment is a good choice. So in this paper, we focused on Wireless Energy Harvesting in Interference Alignment Networks, the main works can be described as follows:(1)In the multi-user relay network, this paper considering a Simultaneous Wireless Information and Power Transfer mechanism in an Interference Alignment network. In the network, the source nodes send wireless information and energy simultaneously to relay nodes, and relay nodes forward the received signal to destination nodes powered by harvested energy. To manage the interference effectively and utilize interference as source energy,two SWIPT transmission scheme is designed, named Power Splitting(PS)and Antennas Switching(AS)has considered for the relay system. We present the optimal transmission design of these two scheme. Later,a new Energy Cooperation( ECop) scheme that is proposed to improve system performance. It is shown from the simulation that the performance of proposed ECop outperformed than both AS and PS.(2)In the Cognitive Radio(CR)networks,the access of Secondary users(SUs)can't make an influence to the Primary user(PU)beyond the limit,so the precoding matrix design of the SUs should take the reduction of interference to the PU into account first.It is a good scheme that make the interference come from SUs aligned into the same subspace within the PU. Furthermore, Considering the specialty of Energy Harvested users, whether the energy signal comes from itself or the others' interference signals, which can be a source of energy,even the energy users can make a greater sacrifice for the information transmission users, so that the information transmission users can achieve a better performance. For this reason, this paper provides two code schemes,one is making the interference of all SUs aligned to a subspace with the PU, while the other one is to guarantee the alignment of both SUs and PU, and keep the Energy users' interference aligned to the same space with the information users. Finally,to guarantee the performance of both PU and SUs,the PU's precoding matrix and the SUs' decoding matrices are designed.