| In recent years,with the advent of the 5G era and the vigorous development of the Internet of Things,the derived technologies such as cloud computing,big data and artificial intelligence are also making breakthroughs.With the development of technology,the ever-increasing number of users has also resulted in an exponential explosion of data traffic.In the face of huge volume of traffic data,how to ensure fast rate,large-capacity data transmission,and further improve spectrum utilization and increase channel capacity has become an urgent problem that people want to solve.Therefore,in the case of very tight low-frequency spectrum resources,in order to carry the growing large-scale traffic data as much as possible,improving the modulation method and coding technology used in the current communication field has become the key to the problem.The research of momentum technology has also become a hot spot at present.Most of the current research on orbital angular momentum stays on the design of OAM antennas.Therefore,aiming at the principle of orbital angular momentum technology based on circular antenna array,this paper designs a new method of encoding and decoding orbital angular momentum,and repeats experiments according to this method,and finally successfully realizes efficient and stable system-level orbital angular momentum multiplexing communication,and has better channel capacity performance than MIMO communication.The main research contents of this paper are as follows:Firstly,this paper designs a novel method of encoding and decoding orbital angular momentum communication based on the principle of generating electromagnetic waves of orbital angular momentum and the characteristic that signals carrying different orbital angular momentum modes are orthogonal to each other.Mathematical model of link and multi-link multiplexed orbital angular momentum communication systems.At the same time,the influence of the system’s signal-to-noise ratio on the bit error rate is analyzed.Finally,it is verified that the method can realize an efficient and stable orbital angular momentum wireless transmission link,which lays a theoretical foundation for the realization of future orbital angular momentum-based wireless communication systems.Then,on the basis of the link model constructed above,by improving the transceiver system,a new topology orbital angular momentum multiplexing method is further proposed,and a wireless communication system with higher performance orbital angular momentum multiplexing is realized.By comparing the channel capacity with the MIMO system simulation,it is verified that the method has a larger channel capacity than the traditional MIMO system under the same number of channels.Finally,this paper uses the non-diffraction technology to realize the convergence effect of electromagnetic waves,which is verified by communication experiments for the first time.Then,the diffraction-free technology is applied to the orbital angular momentum codec model in Chapter 3,and a diffraction-free orbital angular momentum multiplexing communication system model is proposed.And through simulation,it is verified that the system model can realize the multiplex communication of orbital angular momentum without attenuation within the set distance range. |
