Efficient bandwidth allocation scheme for PON system enabling LAN emulation

Emulating the local area network (LAN) has become a vital requirement for the passive optical network (PON). There are many efforts to establish the optical layer LAN (OLAN) in various PONs. However, the existing OLAN schemes generally isolate the LAN function from regular PON, resulting in the rigid allocation of transmission resources. To improve the flexibility of OLAN, this work presents a PON system that can achieve the conversion between PON and LAN. According to different conversions, the system forms three work modes. In addition, a novel bandwidth allocation scheme is proposed for this PON system to determine when to switch its work mode. The proposed bandwidth allocation scheme aims to reuse the idle timeslots due to the half-duplex LAN transmission by sharing the timeslot and wavelength resources between the upstream and LAN transmissions. Simulation results show that the proposed bandwidth allocation scheme can significantly outperform the traditional one in the average latency, network throughput, and load balancing performances.