Abstract Mobile data traffic as the two main forces for the development of future communications, mobile Internet and Internet of Things give the fifth generation of mobile communications (5G) unlimited possibilities and prospects. A large number of mobile device access and shortage of spectrum resources are also issues that 5G needs to face. Based on the understanding of wireless communication multiple access, a low complexity FPGA implementation solution based on 5G wireless communication sparse code multiple access system is proposed, and the synthesizable Verilog language is used in QuarLusII and ModelSim platforms. The integrated design of the circuit and the FPGA verification are completed, and the results prove that the design is complete and can be used in practice. In the scenario of downlink multiple access, a high-performance blind detection algorithm based on sparsity constraints is also proposed. Considering the sparsity of the system, a corresponding mathematical model is established, and a probability parameter is used to characterize the sparsity of the system, thereby approaching the maximum posterior probability detection performance. In addition, using the sparsity of the system, we developed a constrained detection and derived a priori metric, thereby reducing complexity. Through verification, the performance of the blind detection algorithm proposed in this paper can approach MAP detection, and has significant gains in performance and complexity compared to traditional SD algorithms.