Low-complexity probabilistic shaping based on bit-weighted distribution matching in DMT-WDM-PON

We introduce a novel probabilistic shaping (PS) scheme based on bit-weighted distribution matching (BWDM) into a discrete multi-tone wavelength division multiplexing passive optical network (DMT-WDM-PON) employing low-density parity-check-coded 16-ary quadrature amplitude modulation (16QAM). Unlike the prevailing arithmetic coding-class PS schemes with target symbol probability, such as arithmetic distribution matching and constant composition distribution matching, the proposed one realizes Gaussian-like symbol probability distribution emulation merely based on simple bit-class processing, having the advantage of much lower computational complexity. As the key operation in BWDM, the bit weight intervention is implemented in the process of PS-16QAM generation for elevated transmission probability of binary data ‘0’ by cascaded operations of weight bit labelling and bit reconstruction. The experimental results show that, compared with uniformly-distributed signal with the same net rate, significantly-improved receiver power sensitivity and system tolerance to optical fiber nonlinear effect can be obtained in the DMT-WDM-PON system. The proposed PS scheme can be considered as one of promising practical solutions for more available optical network units due to enlarged system power loss budget for the optical distribution network.