Research On Non-orthogonal Multiple Access With SWIPT In The Next Generation Wireless

More and more terminal equipments would like to join the networks,the wireless communications and data business kept on increasing explosively.However,the desire for higher data rate and better wireless service never stopped growing.The crowded network and limited communication resources are becoming more and more difficult to meet the growing demand for mobile communication services.Non-orthogonal multiple access technology can effectively enhance the spectral efficiency of the system,support a large number of users to access the communication network at the same time,and effectively alleviate the tight communication resources.Therefore,the research of the new multiple access technology and the new solution around the multiple access technology is of great significance.In this thesis,we focus on the research of NOMA related multiple access scheme and aim to build a multiple access solution suitable for future wireless communication.First of all,the paper has studied the basic principle of non-orthogonal multiple access technology:Interleave Division Multiple Access(IDMA);Power Domain Non-orthogonal Multiple Access(PD-NOMA);Simultaneous Wireless Information Power transfer(SWIPT).Then,according to the IDMA technology,we propose the SWIPT aided(Orthogonal Frequency Division Multiple-interleave Division Multiple Access)OFDM-IDMA scheme and SWIPT technology,and based on the PD-NOMA technology,an energy harvesting and PD-NOMA based on VLC(Visible Light Communication)/RF(Radio Frequency)hybrid cooperative communication system is proposed.The main contents and contributions of this paper are as follows:We propose to combine OFDM-IDMA with SWIPT,resulting in SWIPT aided OFDM-IDMA scheme for power-limited sensor networks.In the proposed system,the base station applies Power Splitting(PS)to coordinate the Energy Harvesting(EH)and Information Decoding(ID)process,where the harvested energy is utilized to guarantee the iterative Multi-User Detection(MUD)of IDMA to work under sufficient number of iterations.Our objective is to minimize the total transmit power of user,while satisfying the requirements of both minimum harvested energy and Bit Error Rate(BER)performance from individual receive nodes.We formulate such a problem as a joint power allocation and splitting one,where the iteration number of MUD is also taken into consideration as the key parameter to affect both EH and ID constraints.To solve it,a sub-optimal algorithm is proposed to determine the power profile,PS ratio and iteration number of MUD in an iterative manner.Simulation results verify that the proposed algorithm can provide significant performance improvement.Then,we introduce a dual-hop VLC/RF PD-NOMA aided SWIPT system to extend the coverage of indoor VLC systems with no extra energy consumption.A near user which can communicate with the LED source directly act as energy harvesting relay and Decode-and-Forward(DF)relay simultaneously between the two hops.The near user first harvests energy from the received VLC signal and detects the information and then forwards the information to the far user over RF channel using the harvested energy,where the far user can not communicate with the LED source directly due to the limitation of VLC.We analyze the effect of energy harvesting on system performance.It was found that exits a optimal ratio which minimizes the outage probability and capacity.