Solutions for a single carrier 40 Gbit/s downstream long-reach passive optical network

This paper presents a single carrier 40 Gbit/s downstream long-reach passive optical network (LR-PON) topology as candidate for upgrading cur rent f ber infrastructure towards higher data rates. A 100 km LR-PON network was investigated and 2 solutions to overcome chromatic dispersion were proposed. Firstly, a dispersion compensated element is added to compensate the mean length of the feeder f ber. Secondly, an advanced modulation scheme, i.e. 3-level electrical duo-binary is introduced. This scheme has the advantage of allowing lower bandwidth APDs and requires only limited additional electronics. Furthermore, to overcome the inherent discrepancy between aggregated line rate and user rate, and hence the reduced power effciency, the BiPON protocol is added to minimize signal processing at the high line rates

Determination of optimized sleep interval for 10 gigabit-passive optical network using learning intelligence

The overall aim of this project is to investigate the application of a machine learning method in finding the optimized length of asleep time interval (TAS) in a cyclic sleep mechanism (CSM). Since past decade, the implementations of CSM in the optical network unit (ONU) to reduce the energy consumption in 10 gigabit-passive optical network (XG-PON) were extensively researched. However, the newest era sees the emergence of various network traffic with stringent demands that require further improvements on the TAS selection. Since conventional methods utilize complex algorithm, this paper presents the employment of an artificial neural network (ANN) to facilitate ONU to determine the optimized TAS values using learning from past experiences. Prior to simulation, theoretical analysis was done using the M/G/1 queueing system. The ANN was than trained and tested for the XG-PON network for optimal TAS decisions. Results have shown that towards higher network load, a decreasing TAS trend was observed from both methods. A wider TAS range was recorded from the ANN network as compared to the theoretical values. Therefore, these findings will benefit the network operators to have a flexibility measure in determining the optimal TAS values at current network conditions

An energy-efficient distributed dynamic bandwidth allocation algorithm for Passive Optical Access Networks

The rapid deployment of passive optical access networks (PONs) increases the global energy consumption of networking infrastructure. This paper focuses on the minimization of energy consumption in Ethernet PONs (EPONs). We present an energy-efficient, distributed dynamic bandwidth allocation (DBA) algorithm able to power off the transmitter and receiver of an optical network unit (ONU) when there is no upstream or downstream traffic. Our main contribution is combining the advantages of a distributed DBA (namely, a smaller packet delay compared to centralized DBAs, due to less time being needed to allocate the transmission slot) with energy saving features (that come at a price of longer delays due to the longer queue waiting times when transmitters are switched off). The proposed algorithm analyzes the queue size of the ONUs in order to switch them to doze/sleep mode when there is no upstream/downstream traffic in the network, respectively. Our results show that we minimized the ONU energy consumption across a wide range of network loads while keeping delay bounded.Postprint (published version

An FPGA implementation of a sleep enabled PON system

Owing to the growing demand for bandwidth-hungry video-on-demand applications, Passive Optical Network (PON) has been widely considered as one of the most promising solutions for broadband access. Environmental concerns motivated network designers to lower energy consumption of optical access networks. A well-known approach to reduce energy consumption is to allow network elements to switch to the sleep mode. In this framework, an improved Optical network Unit (ONU) architecture in TDM-PON is proposed to reduce the handover time of status switching. Energy-saving performances of current and improved architectures are compared in different scenarios. The simulation results show that by applying a proper sleep mode mechanism, the improved architecture can effectively reduce the ONU energy consumption. We further implement the cycle sleep scheme on a multi-ONU testbed based on the improved ONU architecture. The experimental results have substantiated the viability of the improved ONU architecture

Energy Efficient Frame Structure for Gigabit Passive Optical Networks

Increasing power consumption in information and communication access networks is one of the major cause of greenhouse gas emissions. These emissions are harmful to life on earth. Passive Optical Networks (PONs) are energy efficient but the broadcast nature of downstream traffic may cause of huge unnecessary processing of frames by the optical network units and result in significant energy wastage. Bi-PON technique tried to solve this problem by changing the XGPON / GPON frame structure to an interleaved pattern but also required additional hardware changings at the optical network units.  In this study, we have tried to achieve the same objective by making a few changings in the GPON frame structure without modifying the existing hardware structure. The simulation results show that 25.25% processing energy of an ONU can be saved by incorporating these changes

Impact of reciever on time on the energy saving performance of the watchful sleep mode in a passive optical network

Due to increasing bandwidth demands from users, this evolution towards next generation PON (NG-PON) with higher network capacity and split continues. However, increasing split ratio in NGPON also leads to higher power consumption of the PON network due to 60% of the power is being consumed by the optical network units (ONUs). For energy conservation of the ONU, the Watchful Sleep Mode (WSM) has been recently added to the PON standards. This is an integrated mode that combines both the cyclic sleep and doze mode in one operation by periodically turning on the ONU receiver (RX) during the sleep cycle. However, still, the impact of RX on time on the energy saving performance of WSM has not been studied. Therefore, this study presents a performance evaluation of the watchful sleep mode in a 10 GB-capable PON (XG-PON) network with varying RX ON times. The investigation is performed with a dynamic bandwidth assignment scheme and real traffic data from Broadcom CATV head end. A comprehensive review of the power saving techniques for XGPON is also presented. The simulation study results show that higher RX ON time leads to higher energy savings for the ONUs without significantly increasing upstream and downstream delays