Joint Wavelength, Antenna, and Radio Resource Block Allocation for Massive MIMO Enabled Beamforming in a TWDM-PON Based Fronthaul

Massive multiple input multiple output (mMIMO) enabled beamforming is a promising technology in the next generation of mobile communication. It allows multiple antennas transmit the same data to a user to improve the signal strength and quality. However, beamforming may incur redundant data transmission over fronthaul in the centralized radio access networks. When accommodating a set of beam requests, a key problem is how to coordinate radio and optical resources to maximize the beamforming throughput and minimize the fronthaul bandwidth. In this paper, we study on the joint wavelength, antenna, radio resource block allocation (WARA) in a time and wavelength division multiplexed passive optical network, which is an economic fronthaul solution for the mMIMO. We formulate the WARA into an integer linear programming (ILP) model. Three heuristic algorithms are proposed to optimize fronthaul bandwidth, radio resource block (RB) utilization, and both. We compare ILP with the proposed algorithms under different sizes of antenna arrays. A tradeoff is shown to exist between fronthaul bandwidth and radio RB utilization. Also, we find that the optimization goal depends on the number of antennas in an optical network unit.