Real-time implementation of a sphere decoder-based MIMO wireless system

This contribution analyzes the integration of the sphere decoder (SD) in a complete field-programmable gate array (FPGA)-based real-time multiple input-multiple output (MIMO) platform. The algorithm achieves the performance of the maximum likelihood detector (MLD) with reduced complexity. However, its non-deterministic complexity, depending on the noise level and the channel conditions, hinders its integration process. This paper evaluates the performance and limitations of the SD in a real-time environment where signal impairments, such as symbol timing, imperfect channel estimation or quantization effects are considered.