Study and Demonstration of Sleep and Adaptive Link Rate Control Mechanisms for Energy Efficient 10G-EPON

Evaluating Energy Efficiency of ONUs Having Multiple Power Levels in TDM-PONs

“…Besides, Table I includes a set of notations along with their meaning that we will be using in this letter to describe our analytical model. As proposed in [3], [8], we assume in our model that when an ONU does not have anything to receive the OLT computes the sleep interval using an algorithm (we explain this in Section III). Then, the OLT initiates SRS with that ONU, as shown in Fig.…”

“…Hence, it is considered in [2], [8] that the OLT assigns consistently a minimum amount of uplink slot to each sleeping ONUs in each Tc. By doing so, a sleeping ONU can initiate PRS for getting an uplink transmission slot from the OLT.…”

“…Therefore, D accumulates n sleep cycles. Let e j represents the event meaning that there is at least one frame arrival during the jth monitor period for the ONU-m. Then P r(e j = true) = 1 − e −λm(Tj +L) , where λ m is the downlink frame arrival rate for the ONU-m and it follows Poisson process as considered in [8]. Then the probability of having jth sleep interval (P r(n = j)) is P r (no frame arrivied in monitor period 1, 2,.., j − 1) P r(at least 1 frame arrived during jth monitor period) and it is expressed as follows [10]:…”

“…Toward this end we compare analytical results with simulation results (we use a C++ discrete event simulator developed in our work). The first algorithm is the Fixed Sleep Interval (FSI) [8]. In FSI, the OLT always assigns a fixed sleep interval Ts in absence of downlink frames for an ONU.…”

“…We use the following parameters in our evaluation: L R = 1 Gbps, F s = 1518 bytes, t pl = 0.2 ms, L = 1.6 ms [8], Tmax = 50 ms [5], T b = 1000 ms, and number of ONUs per OLT is 32. We assume that the utilization of T slot is a 100% and there is no frame loss between the OLT and an ONU.…”