Design and hardware implementation of a low-complexity multiuser vector precoder

In the multiuser MIMO broadcast channel, the use of precoding techniques is required in order to detect the signal at the users´ terminals without any cooperation between them. This contribution presents the design and hardware implementation of a high-capacity precoder based on vector perturbation. The most challenging part of the vector precoding (VP) scheme, that is, the search for the perturbing signal in an infinite lattice, has been completed by the reduced-complexity albeit high-performance Fixed Sphere Encoder (FSE) algorithm. The most remarkable feature of the FSE is its fixed complexity, which makes it highly suitable for hardware implementation on field-programmable gate arrays (FPGA), where the parallelization and pipelining of resources can be applied to enhance the system throughput. An optimized reduced-complexity implementation is proposed, which achieves high performance with a reduced hardware resource usage.