Study on precoding optimization algorithms in massive MIMO system with multi-antenna users

  1. Photo Evgeny Bobrov Evgeny Bobrov
  2. Photo Dmitry Kropotov Dmitry Kropotov
  3. Photo Sergey Troshin Sergey Troshin
  4. Photo Danila Zaev Danila Zaev

The paper studies the multi-user precoding problem as a non-convex optimization problem for wireless multiple inputs and multiple outputs (MIMO) systems. In our work, we approximate the target Spectral Efficiency function with a novel computationally simpler function. Then, we reduce the precoding problem to an unconstrained optimization task using a special differential projection method and solve it by the Quasi-Newton L-BFGS iterative procedure to achieve gains in capacity. We are testing the proposed approach in several scenarios generated using Quadriga-open-source software for generating realistic radio channel impulse response. Our method shows monotonic improvement over heuristic methods with reasonable computation time. The proposed L-BFGS optimization scheme is novel in this area and shows a significant advantage over the standard approaches. The proposed method has simple implementation and can be a good reference for other heuristic algorithms in this field.