Efficient Dynamic Bandwidth Allocation Schemes in Long-Reach Passive Optical Networks- a Survey

Long Reach Passive Optical Networks (LR-PON) concept is offered as a cost-efficient solution to bring the fiber to the Home, Office, Curb, Building etc. (FTTX). It extends the reach and capacity of traditional PON from similar to 20 km to similar to 100 km using the optical amplifiers. It merges the metro and access domains by reducing the number of central offices (CO). This approach reduces capital and operational expenditure by reducing number of components, along with the network power consumption and design complexity. Transmission-messages are exchanged between the optical-line terminals and optical network units before the actual data transmission. By extending the reach, these messages are delayed due to increased Round Trip Time (RTT) which degrades the performance of dynamic bandwidth allocation (DBA) algorithms. Several schemes have been proposed to overcome such challenges. This paper presents a survey of different DBA schemes for Long Reach EPONs with their pros and cons. Comparative summary of these schemes is presented. We also discuss our proposed idea to enhance Quality of Service (QoS) with efficient DBA at the end of the paper.