Research On Power Allocation Technology For Multi-Mode OAM-MIMO Multiplexing

Orbital angular momentum(OAM),as a component of electromagnetic radiation,has attracted wide attention due to its physical orthogonality,which provides new degrees of freedom for the shortage of wireless resources.The multi-mode OAM-MIMO multiplexing communication system can use the orthogonal characteristics between different OAM modes to freely select OAM modes to transmit multiple channels of information.This thesis focuses on the multi-mode OAM-MIMO multiplexing communication system to perform system modeling and performance analysis on direct,multipath,and dynamic channels respectively,and proposes adaptive power allocation methods based on different channel scenarios.The main contents are summarized as follows:This thesis first establishes and analyzes a multi-mode OAM-MIMO multiplexing transmission model in direct channel,and proposes a power allocation algorithm based on mode selection.This algorithm makes use of the differences between different mode channels to quickly allocate the power of each modal channel.The theoretical analysis compares the complexity of the proposed algorithm with traditional algorithms,and simulations verify that the proposed algorithm can reduce the complexity without losing system performance.Secondly,this thesis proposes a mode and subcarrier joint allocation algorithm combining OAM mode and orthogonal frequency division multiplexing technology in multipath channels.By separately performing power allocation on both the modal and the sub-carrier,it is possible to flexibly control the power value of each modal,and the difference between different mode channels can be used to quickly allocate the power value.Through simulation verification and analysis,compared with direct power allocation,the algorithm can effectively reduce the complexity.Finally,this thesis proposes a power pre-allocation algorithm with unknown channel state information(CSI)under dynamic channels.Based on the symmetry of the vortex wave radiation field,the known mode channel state information is used to predict the next mode channel state.Simulation results show that compared with the average power allocation and continuation of the previous power allocation algorithm,the power pre-allocation algorithm can obtain a capacity gain equivalent to the known CSI under unknown CSI conditions.