Jun Sugawa

Architecture and Design of IP Broadcasting System Using Passive Optical Network

We propose an IP broadcasting system architecture using passive optical networks (PON) utilizing the optical broadcast links of a PON with a downstream bandwidth allocation algorithm to provide a multi-channel IP broadcasting service to home subscribers on single broadband IP network infrastructures. We introduce the design and adaptation of the optical broadcast links to effectively broadcast video contents to home subscribers. We present a performance analysis that includes the downstream bandwidth utilization efficiency of the broadcast link and the bandwidth control of the IP broadcasting and Internet data. Our analysis and simulation results show that the proposed system can provide 100 HDTV channels to every user over fiber lines. We also propose an IPTV channel selection mechanism in an ONT by selecting a broadcast stream. We developed and evaluated a prototype that can achieve a 15-msec IPTV channel selection speed.

High-Definition IPTV Broadcasting Architecture Over Gigabit-Capable Passive Optical Network

Service providers are currently seeking to offer high-quality IP video service on single broadband IP network infrastructures, including ADSL and passive optical networks (PON). One of motivation of our work is increasing the bandwidth utilization efficiency of video data delivery to home subscribers and reducing the channel zapping time. We propose a high-definition IPTV broadcasting architecture over GPON that can provide 100 HDTV channel over fiber lines in this paper consisting of a Gigabit-capable passive optical networks (GPON), IPTV terminals, an IP broadcasting server, and an IP broadcasting management server. We adapt the optical broadcast nature of a GPON to IP multicast networks to effectively broadcast video content to home subscribers. We develop IPTV channel selection mechanism in the GPON ONT by selecting a multicast stream at a subscribers home that can achieve a 10-msec IPTV channel selection speed.

Dynamic-load-balancing algorithm suppressing the number of wavelength reallocations for λ-tunable WDM/TDM-PON

We propose a dynamic-load-balancing algorithm that is derived using Jains fairness index. Simulation results show that the proposed algorithm can distribute traffic loads among PON-branches quite fairly with a very small number of wavelength reallocations compared with a round-robin approach.

10.3Gbps burst-mode receiver capable of upstream transmission with short overhead for 10G-EPON

We developed a 10.3Gbps burst-mode receiver with a gain switching TIA and burst-reset control for a 10G-EPON OLT. It can perform burst transmission with an overhead of 280ns while satisfying receiver sensitivity and overload required in IEEE802.3av PR30.

512-ONU real-time dynamic load balancing with few wavelength reallocations in 40 Gbps λ-tunable WDM/TDM-PON [Invited]

The wavelength (λ)-tunable wavelength-division multiplexing/time-division multiplexing passive optical network (WDM/TDM-PON) can distribute traffic loads fairly by dynamically reallocating a certain number of optical network units (ONUs) from highly loaded optical subscriber units (OSUs) to lightly loaded OSUs. This reallocation can be executed by hitless λ-tuning. However, hitless λ-tuning causes delays or fluctuations in traffic. To reduce these penalties, the number of wavelength reallocations should be suppressed. Thus, we proposed a dynamic-load-balancing (DLB) algorithm that can distribute traffic loads among OSUs with few wavelength reallocations. However, no demonstration of the proposed DLB algorithm had been conducted up to now, and the impact of the reallocation frequency on the average latency remained unevaluated. In this paper, we demonstrate the DLB algorithm in a 40-Gbps λ-tunable WDM/TDM-PON. The demonstrations confirm that our DLB algorithm can distribute 512-ONU traffic loads fairly among 4 OSUs in real time with fewer reallocation frequencies compared to the conventional round-robin algorithm, and little impact on average latency, with various input traffic rates.

Wavelength switching method combined with downstream queue monitoring per ONU for λ-tunable WDM/TDM-PON

We propose a wavelength switching method combined with queue status monitoring per ONU to improve latency of λ-switching ONU while frame loss is prevented for λ-tunable WDM/TDM-PON. Latency degradation by λ-switching of less than 4.1 ms was achieved.

Novel Automatic Service Restoration Technique by Using Self-Reconfiguration of Network Resources for a Disaster-struck Metro-Access Network

This paper shows the concept of the elastic lambda aggregation network (EλAN) that will achieve an elastic common access infrastructure for the metro-access network. It proposes a service restoration technique that uses optical path switching and intercentral office handover for EλAN to recover from disasters. The feasibility of the proposed service restoration technique is successfully demonstrated for the first time by using a prototype testbed of a metro-access network. By applying both orthogonal frequency division multiplexing and adaptive modulation, the system automatically changes the transmission parameters (modulation level, the number of subcarriers, and symbol rate) according to the service requirements and conditions of the optical distribution network, such as the links end-to-end optical loss, in order to achieve accommodate multiple services. In the experiment, an optical network unit in a faulted system automatically reconnected within 10 s to another office 20-km away with the same throughput.

First-time Demonstration of Automatic Service Restoration by Using Inter-Central-Office OLT handover and Optical Path Switching in Metro-Access Network

The first demonstration of the service restoration technique for metro-access networks successfully shows that ONU accommodated by the disaster-stricken central office is automatically reconnected within 10 sec to another office 20-km away with the same throughput as before disaster.

Fairness-aware dynamic sub-carrier allocation in distance-adaptive modulation OFDMA-PON for elastic lambda aggregation networks

In this paper, fairness-aware dynamic subcarrier allocation (DSA) in a distance-adaptive modulation orthogonal frequency division multiple access passive optical network (OFDMA-PON) is proposed and experimentally demonstrated for elastic lambda aggregation networks (EXANs). By applying the distance-adaptive modulation function to OFDMA-PONs, the system can change the transmission parameters (modulation level and symbol rate) for each user according to the users end-to-end optical loss, which will yield additional bits. Meanwhile, by applying our proposed DSA algorithm, which allocates sub-carriers to users based on transmission parameters and traffic demands, the additional bits can be shared by all users in a fair manner regardless of a users end-to-end optical loss. This paper conducts a real-time demonstration using an optical coherent OFDMA transceiver and a medium-access control board. The experiments confirm that our algorithm can greatly improve fairness in terms of frame loss rate among users compared to fixed sub-carrier allocation.

Adaptive FEC control in downstream collaborating with traffic control in OLT for WDM/TDM-PON

We proposed adaptive FEC control that collaborates with downstream traffic control for passive optical networks. Successful operation of the adaptive FEC control in downstream based on downstream BERs of each ONU was demonstrated using a WDM/TDM-PON prototype.