Shigeo Amemiya

Phased Aligned Passive Bus (PAB) Scheme for ISDN User-Network Interface

This paper proposes an alternative to the passive bus realization of the current CCITT ISDN user-network interface. Our new approach is termed phase aligned passive bus (PAB) scheme. An automatic phase adjusting mechanism using a monitor bit is employed in the terminal equipment. This scheme enables the terminals to operate in complete phase synchronization on a passive bus. The advantages that result from this technique are: 1) Eliminates, in principle, the bus length limitation due to round-trip delay time. If line bit rate of 192 kbit/s is kept, then a practical bus length is about 700 m with no limitation on terminal distribution. 2) Allows various extended bus configurations, such as simple repeatered extention, connection of optical link, and multibranched passive bus. 3) Provides spare bit transmission capability to facilitate intrabus communication and maintenance. As an alternative it keeps the general framework of the current CCITT I-series standard such as B + B + D channel structure and LAP- D protocol. Experiments realizing long passive buses are shown to confirm the feasibility of the proposed scheme. This concept is also shown to be applicable to a 2-wire full duplex user-network interface, advantageous in the existing office environment, employing time compression transmission.

Subscriber access scheme for broadband ISDN

The authors discuss the architecture of broadband integrated services digital network (B-ISDN) in accordance with CCITT standardization and propose a ring-based subscriber access network to obtain higher transmission efficiency and flexibility in bandwidth allocation. A distributed access control scheme is used for this application because of its large network size. They study customer premises networks based on the agreement of the Geneva meeting of June 1989, and propose a physical star/logical bus network configuration for the introduction phase of B-ISDN. It allows easy and reliable realization of the broadband customer premises network. They propose an optical passive bus as the most economical configuration because it is applicable to both residential and small-business customers. It is also applicable to large-business customers as the branching network of the other active backbone network. The authors study the feasibility of this optical passive bus, focusing on medium access control.<<ETX>>

An architecture of optical passive bus for broadband CPN (customer premises network)

The authors discuss the broadband customer premises network (CPN) configuration for B-ISDN (broadband integrated services digital network) and propose an optical passive bus scheme with ATM (asynchronous transfer mode) access. To confirm the feasibility of the optical passive bus, the authors studied optical level diagrams and the collision on ATM multiple access. Novel techniques of level control and collision control are introduced. An intra-CPN communication scheme is also proposed. An optical passive bus scheme with multipoint connections and possible application to CCITT standards is also shown.<<ETX>>