Algorithm of both release and allocation bandwidth for downstream channel in multi-OLT PON

A passive optical network (PON) with multiple optical line terminals (OLTs) will play an important role in the optical access network. In this study, a novel dynamic bandwidth allocation (DBA) algorithm for the downstream channel in a multi-OLT PON is proposed. To take care of bandwidth demands of different users, weight factors are introduced. Based on different weight factors, a core framework of the algorithm is constructed. Moreover, by combining a decision criterion and a bandwidth surplus ratio, a mathematical model of release bandwidth is established. Furthermore, by uniting judgement conditions and overload amount, a mathematical model of allocation bandwidth is also built. By constructing two mathematical models, the order and amount of release and allocation bandwidth are effectively solved. Moreover, to describe accurately the power of bandwidth transfer, a new concept ‘bandwidth-transfer work’ is introduced. Based on the bandwidth-transfer work, a ranking model is created to maximise the efficiency of the DBA. Finally, the effectiveness of the DBA algorithm and ranking model is demonstrated by the simulation and analysis.