IEE Proceedings - Communications

A step-by-step decoding algorithm is presented for double-error-correcting binary BCH codes of length n=2m-1. The decoding algorithm can directly determine whether any received bit is correct or not without knowing the number of errors which have occurred in the received vector and also without determining the corresponding error location polynomial. The merits of the hardware decoder b... View full abstract»

In a previous paper (1984) the author presented an iterative code construction for the statistically self-synchronising T-codes. This original set augmentation algorithm is reviewed. The author then generalises the construction, thereby significantly enhancing the range of T-code sets for which the self-synchronisation properties and error-decoding bound are shown to be preserved View full abstract»

The demand for increased bandwidth to support new services, which integrate diverse media, has led to the introduction of broadband integrated services digital networks (B-ISDN). Two-layer video encoding algorithms for asynchronous transfer mode (ATM) networks are examined. Three encoding schemes are considered to prioritise the data using either requantisation or spectral separation or a proposed... View full abstract»

The connection optimisation problem for two types of multipoint videoconferences is formulated. The first type is called a selectable media conference. In this type each conferee can choose to receive a particular video composition. In the second type, called a common media conference, only one composite video is generated for all conferees in this type of conference. Algorithms that use a combina... View full abstract»

In land mobile-radio networks, nodes cannot sense the carrier transmitted from other nodes. Idle-signal casting multiple access with collision detection (ICMA/CD) is a centrally controlled multiple-access protocol in which a base station senses a shared inbound channel (node-to-base station) and broadcasts the channel information on a separate outbound (base station-to-node) channel. A nonpersiste... View full abstract»

Reed-Solomon (RS) error-correcting codes are often proposed for communication systems requiring burst-error-correction capabilities. The performance of RS codes is examined for the case when symbol errors are dependent and therefore not random. This situation arises when interleaving is not possible due to delay constraints, such as in most voice-communication systems. The performance is compared ... View full abstract»

A link group is a bundle of channels interconnecting a pair of nodes. The author presents an ATM switch design which both unichannel and multichannel connections to be carried on each link group simultaneously. For a unichannel connection, all cells are to be transported over the channel of a link group. In contrast, cells belonging to a multichannel connection are allowed to be transported over d... View full abstract»

The authors consider the dynamic control of time slot assignment in reservation protocols for multiaccess channels employing frame structures similar to those investigated by Roberts (1973) and others. Such protocols are particularly suitable for channels with long propagation delays, such as satellite channels. Fixed length frames are dynamically divided on a frame by frame basis into reservation... View full abstract»

A high-capacity switch is an essential component for the success of broadband ISDN. A nonblocking ATM switch with input and output buffers is proposed and its performance is evaluated. The proposed switch is a modified version of an existing distributed-knockout-switch. In the proposed switch architecture, an input port with a nonempty queue always sends a cell to the switch at the beginning of ea... View full abstract»