Research On Resource Allocation Algorithm Of SM-NOMA System Based On Intelligent Reflector Surface

With the rapid development of wireless communication technology,the data flow presents an explosive growth.The Intelligent Reflecting Surface(IRS)has become a promising research topic in the field of wireless communication because of its low cost and light weight.The IRS is made up of multiple reflection units,which are made of low-cost electromagnetic materials coated on tall buildings.According to the environment of the wireless channel,the IRS uses programmable devices to enable each reflection unit to generate phase offset to the incident signal,and improving the communication performance of the system.In order to improve the anti-fading ability of the communication system,in addition to deploying a large number of passive reflection units on the IRS,the Non-orthogonal Multiple Access(NOMA)technology is introduced into the IRS system.NOMA technology uses the method of power domain reuse to achieve new degrees of freedom.By using serial interference elimination technology,multiple users in the same resource block can be divided and decoded,which can meet the demand of 5G mobile communication for spectrum utilization,power consumption and access volume to a large extent.In order to improve the performance of the system,we introduce IRS into spatial modulation aided NOMA communication system,namely IRS-SMN system.Based on the constraints of base station transmission power and IRS phase,we establish a resource allocation model to maximize the multi-user rate.A joint optimization algorithm of IRS phase and station power allocation based on SM was proposed.Firstly,users are grouped based on channel gain,and then the phase shift matrix is solved by using Semi-definite Relaxation(SDR)method.Finally,the power distribution factor is solved by geometric programming.Simulation results show that the proposed algorithm can effectively improve the sum rate of the system,and has better bit error rate performance at the same transmission rate.In order to further improve the utilization of spectrum resources,a generalized spatial modulation(GSM)-NOMA system model with IRS assistance is proposed,namely IRS-GSMN system.A resource allocation model based on the minimum rate requirements of each user was constructed by considering the power constraints of the base station side transmission and the IRS phase constraints.A joint optimization algorithm based on GSM was proposed for the power allocation of the intelligent reflector phase and the base station.Firstly,users are grouped based on the location correlation,then the cosine similarity method is used to solve the IRS phase shift matrix,and finally,the power distribution factor is obtained according to the power distribution scheme which the minimum rate demand of each user,the simulation results also verify that the proposed algorithm can effectively improve the sum rate and bit error rate of the system.