This paper proposes an optical broadcast-and-select network architecture with centralized multi-carrier light source (C-MCLS). A large number of optical carriers/wavelengths generated by C-MCLS are distributed to all edge nodes (ENs), which select and modulate wavelengths to realize transmission. To utilize wavelength resources efficiently, we introduce a framework of wavelength allocation and selection (WAS). Wavelength allocation is performed at a wavelength control server, while wavelength selection is done at each EN according to wavelength allocation results. Both static and dynamic schemes are adopted for WAS and their implementations are shown. By using fixed or tunable band pass filter and periodical arrayed waveguide grating demultiplexer, wavelengths are selected and utilized by ENs in a static or dynamic manner. We evaluate network cost and performance of the proposed network. Cost analysis and numerical results show that it offers greatly reduced cost compared to the conventional one when the number of required access wavelengths at EN becomes large. We delineate its applicable areas through cost comparisons. Blocking probabilities of static and dynamic schemes are analyzed to evaluate network performance. Numerical results show that by choosing appropriate design parameters, the dynamic scheme offers about 25% increase in admissible offered load under the specified blocking probability, compared to the static scheme. This indicates that the dynamic scheme makes the proposed network more robust against traffic fluctuations.

This paper proposes a real-time allocation scheme for photonic networks that use wavelength division multiplexing (WDM) and optical time division multiplexing (OTDM) technologies in the backbone and ring regional networks, respectively. A frame that is used for transferring data and control information in a ring regional network takes only one round to complete data allocation processing, instead of two rounds as required by the prior reservation scheme, so that data can be transmitted immediately. Our challenge is to provide max-min fair share in terms of throughput with just one round. If no free space is left on the frame, the proposed scheme allows a group (some) of the newly requested data to replace some of the already allocated data to provide max-min fair share, in terms of throughput. Data replacement and de-fragmentation are processed in the optical domain. Simulations show that the proposed scheme maintains max-min fair share even in unbalanced traffic scenarios. The complexity of de-fragmentation depends on the number of delay lines needed to regenerate the original data groups. The maximum number of delay lines is determined.

Real-time traffic will be a predominant traffic type in the next generation networks and 100% reliability and availability of networks will be required by real-time premium traffic (PT). It is believed that QoS guarantees could be better provided by the connection oriented networks such as Multi Protocol Label Switching (MPLS). These connection oriented networks are more vulnerable to network failures. Conventional path protections perform re-routing to cope with them. However, re-routing always causes packet losses and results in service outage. These losses are bursty in nature and highly degrade QoS of the real-time premium traffic. The novel path protection proposed in this paper recovers the bursty packet losses due to re-routing using forward error correction (FEC) path. Therefore, it can provide the network architecture with no service outage for such traffic. The numerical results show that the proposed method can achieve a very high availability for the real-time premium traffic in future IP/MPLS networks. routing (4). However, the problem of re-routing mentioned above still exists, and therefore it is necessary to find proactive techniques to recover the bursty packet losses due to re- routings. The novel idea of path protection with forward error correction (FEC) path proposed in this article can be used for real time premium traffic that needs a guaranteed QoS. It combines a FEC path with conventional path protection methods using re-routings and recovers the packet losses due to re-routings by way of a FEC recovery technique. The numerical result shows that this is a promising proactive technique to provide a guaranteed QoS for real time premium traffic that otherwise can lead to severe effects if 100% availability is not achieved. The rest of this paper is organized as follows. In the next section, the problem description and the existing solutions are analyzed briefly. In Section III, we discuss the proposed method in detail. The performance of the proposed method is evaluated and the results are presented in Section IV. Finally this paper is concluded in Section V.

Peer-to-peer mobile video on-demand (P2MV0D) in the paper by Sato et al. (2006) showed one idea for the decentralized multimedia data distribution on the mobile environment. It allows a moving client to receive streaming data on demand from not only server but other moving clients in a peer-to-peer (P2P) manner, where video contents are divided into the same sized segment and aggregately sent and shared with as many receiving clients as possible. In this paper we discuss deploying P2MV0D under more real mobile environment, which has several delivery domains that have different amount of requests and several types of users that receive a video stream with different bandwidth. We employ the layered video cording and transmission schemes (Deering, 1993; McCanne et al., 1996; Li et al., 1998; Cheung and Zakhor, 1995) for P2MV0D to efficiently provide its service under such environment. The segment is further divided into smaller sized unit referred to as 'slice' and slicing and segmentation are carried out across the layered video streams. Mathematical analysis reveals this strategy reduces the traffic much better than simple use of P2MVOD

This paper presents a new form of video on-demand called 'fragmented patching', which enables clients to move around freely even while receiving video. Patching techniques, which greatly reduce the required network bandwidth through multicasting, have potential for on-demand video distribution. However, patch-flow techniques based on unicast data are unsuitable for providing services to mobile clients because of the intricate process required for relatively short unicast flows to individually follow a moving client. In fragmented patching, however, patch flows are sent via broadcasting. In addition, to avoid increasing traffic due to broadcasting, the patch flows are broken down into segments, each of which is aggregated to be shared with as many multiple clients as possible. We compared the two techniques by using mathematical models, which present the average usage of link bandwidth with the traffic intensity (Erlang), and numerical analysis revealed the aggregation effect by segmenting patch flows countervails the increase in traffic caused by broadcasting patch flows.

In this paper we propose a new scheduler. Deadline fair sharing (DFS), which consists of link scheduling and dropping mechanisms to provide absolute delay and loss guarantees in DiffServ networks. The scheduling mechanism uses dynamic weight associated with each class to schedule the packets and to make a dropping decision when an absolute delay guarantee violation occurs. The dropping mechanism drops packets and detects the onset of an early violation for absolute loss guarantee. When an early violation for the absolute loss guarantee of a class is detected, the scheduling mechanism gives that class more priority for transmitting its packets to prevent that violation. The simulation results show that the proposed scheduler can provide a wide range of absolute loss and delay bounds under various traffic load conditions without controlling the traffic.

In this paper, we propose an innovative information delivery service on intelligent transport systems (ITS), which enables users to see their future vision delivered from users at further points along the route. This service requires special multicast and mobile routing schemes. We have developed a source mobility support multicast (SMM) technique that guarantees consecutive communication in high-speed mobile environments and minimizes the overhead in reconstructing multicast trees, which is caused by a source movement. SMM is based on a new concept where multicast tree is constructed over cellular IP network according to A. G. Valko (1999), in which a source point tree and a rendezvous point tree are combined into one multicast tree. SMM provides wide operability by partitioning the network and confining protocol uniqueness and topological constraints within the local access networks. This paper shows our design of SMM architecture and its detail protocols.

This paper describes a new network scheme that minimizes the consumption of network resources for on-demand streaming-video distribution through multicasting. In general, on-demand video distribution has been realized through unicasting. Asynchronous multicast techniques that reduce the load on the on-demand video server have been studied, but there has been little consideration of ways to reduce the network load. We have developed a statistical traffic-control theory based on asynchronous multicasting that can be used to adjust traffic on the trunk and branch links along the distribution tree to meet the network bandwidth design requirements to ensure QOS. In addition, we propose a dynamic bandwidth-allocation and traffic-adaptation algorithm that allows finite resources to be shared among different video deliveries by assigning the available bandwidth for each according to request rates. To show the implementability of these ideas, we consider their operation with protocols that autonomously construct a multicast tree and guarantee the QOS. We also discuss the effects of using this scheme based on a numerical analysis and simulation results regarding real traffic traces and the service-blocking rate.

In this paper, we propose a new transmission and resource allocation technique on multicarrier direct-sequence CDMA (MC-DS-CDMA). The proposed system allocates subcarriers and spreading codes to users by considering their current bandwidth requirements and frequency shifts caused by their movement. Through the use of low-correlation spreading codes in close subcarriers the scheme reduces the inter-carrier interference generated by high-speed users while keeping the inter-symbol interference at a low level due to the multicarrier transmission. The analysis and results show that a substantial mitigation of both the intercarrier interference and bit error ratio, without reducing the system bandwidth efficiency, can be achieved. That makes our proposed method a god candidate for future broadband highly-mobile networks.

The proposed medium access protocol deals especially with the timely-transmission of real-time packets in wireless multimedia networks where users of various types of traffic are present. It works based on the time division multiple access (TDMA) with time division duplex (TDD) technique as well as fixed-length packet switching incorporating two policies, which work differently during non-congestion and congestion states. The simulation results show good performance of the proposed method, even under high-load conditions, and a good trade-off characteristic between real-time access delay and non-real time buffer occupancy, during periods of congestion.

The key technologies required for the development of optical transport networks, namely, optical fiber transmission and digital transport, which includes transmission signal multiplexing, transport nodes, and network operation functions, are highlighted. The trends in transport technology, the impact of synchronous digital hierarchy (SDH) and asynchronous transfer mode (ATM), the role of telecommunications management networks, and network integrity enhancement techniques are elucidated. It is demonstrated that these technologies have brought about a great change in transport network design and performance. Further innovations are required to fully realize a high-performance computer communication network, a cost-effective nationwide B-ISDN, and local networks for video distribution. These include the realization of an optical access transport network and the extension of trunk network capabilities which will be possible with optical path layer technologies.>

This paper describes fiber optic transport systems for present and future local networks. The present most important fiber optic system in a local network emerges as a broad-band video distribution system, because large-scale system introduction might be attained only for distributed video services. The system architecture and system parameters are presented. As for future integrated services, a highspeed digital transmission system and local network architecture are very important. The network architecture should be constructed to meet the demands for increased flexibility, capacity, reliability, and economy. Considering expected future demands and technologies, a new fiber optic local network architecture is proposed. The architecture's main features are the use of transmission processing nodes and a multilane-ring structure in subscriber transfer networks in combination with star-shaped subscriber access lines.

The hybrid digital transmission system, involving 2Rrepeaters between 3R (Reshaping, Retiming and Regenerating)-repeaters, is a suitable system for fiber-optic transmission. The 2R (Reshaping and Regenerating)-repeatered line enables bit rate free transmission, but cannot suppress the accumulated timing jitter in transmitting pulse streams. The trial 1-8 Mbit/s transmission system, using step-index multimode fibers and light emitting diodes, was designed and tested. Multirepeater transmission experiments using optical fiber cable laid in an underground cable tunnel were also performed. The timing jitter accumulations were measured through the multi-repeatered line. Measured timing jitter values were in good agreement with theoretical values. Experimental results show satisfactory feasibility of a fiberoptic hybrid digital transmission system using step-index or gradedindex multimode fibers.

This paper describes the feasibility and the applicability of the Wavelength-Division-Multiplexing (WDM) system with two types of preliminary WDM transmission experiments. Through this study, it has become clear that WDM technologies play a major role in optical fiber systems and have the possibilities of realizing the various optical fiber transmission systems.