Showing papers on "Transmission delay published in 1977"

A Multiaccess Model for Packet Switching with a Satellite Having Some Processing Capability

Abstract: A multiaccess model for packet switching with a satellite having the capability of interrogating the uplink header and creating the downlink header is proposed. The satellite broadcasts slot assignments, based on the users' reported queue status, to the users for transmission in the next frame. With the protocols being done at both the earth stations and at the satellite, the proposed multiaccess model avoids collisions that are prevalent in schemes of the ALOHA type. The actual model is too complex to handle analytically. We derive analytical equations for a two-group model. Calculated and simulated buffer overflow probabilities as a function of traffic intensity and buffer size are compared. We also evaluate the performance of the actual model in terms of average system delay as a function of traffic intensity by means of computer simulation.

Discrete link capacity and priority assignments in communication networks

Abstract: This paper deals with the problem of discrete link capacity assignment in store-and-forward packet switching communication networks. Our problem formulation calls for minimizing the network cost while satisfying all the average packet delay constraints specified for different classes of packets. Heuristic algorithms which give near-optimal solutions of the problem are developed. We first describe a discrete link capacity assignment algorithm for networks with arbitrarily defined classes of packets having individual delay constraints. The problem of priority assignment on different classes of packets is then investigated, and an algorithm is developed which assigns suboptimal priorities on classes of packets based on parameters such as delay requirement, path length, packet length, and packet rate. These two algorithms for capacity assignment and priority assignment are combined and tested over a number of examples. It is found that a substantial reduction on network cost can be achieved by the use of a simple priority queuing discipline.

Stabilized delay line oscillator

Abstract: A device and technique for providing stability to a coherent delay line clock. A voltage controllable delay is combined with the lumped delay line of a coherent delay line clock to enable the control of the period of the clock. The voltage controllable delay is obtained by comparing the clock count during a predetermined time period against a fixed number N to obtain a difference count. The difference count is then integrated to form a bias voltage for control of the additional delay. The delay line period will then be a ratio of the predetermined period to the fixed number N, which number may be digitally modified to provide a source of variable frequency.

A new technique for satellite broadcast channel communication

Abstract: The goal of this paper is to present a multi-access technique for Satellite Broadcast Channel Communication which extends the features of the Slotted-ALOHA system to higher Channel Utilization and presents a stable behaviour. The Reservation Upon Collision (RUC) Technique consists on a S-ALOHA scheme with a super-imposed reservation technique which automatically operates when collisions occur.The technique is designed to achieve a transmission delay as small as the S-ALOHA for low channel utilization and to perform as a RESERVATION scheme for high channel utilization.The implementation of the RUC-Technique is based upon the knowledge of the origin of the collided packets at each time slot.Simulation results show improved delay-throughput characteristics over S-ALOHA and in particular the suitability of this technique for systems with high channel utilization.

A Reliable Control Protocol for High-Speed Packet Transmission

Abstract: This paper describes a control protocol for high-speed transfers between transceivers in a data communication system. One particularly suitable application of current topical interest would be to control lines linking nodes in a local area packet-switching system. The protocol applies for fixed-length data packets which must ultimately be received at their destination in sequence. With these specifications, a set of rules which is easy to implement in practice is established. The result is a packet interlock method of numbering packet transmissions and jumping back to retransmit a series of packets under error conditions. Problems associated with multiple errors, dummy packets, initial synchronization and resynchronization are investigated and found to be readily overcome by the proposed protocol.

Clock driver circuit

Abstract: PURPOSE: To easily select a time for a period when active levels of an output signal are not overlapped by providing a 1st delay circuit outputting a 1st delay signal and a 2nd delay circuit using a 2nd delay time control signal to delay a 2nd output signal and outputting a 2nd delay signal. CONSTITUTION: The circuit is provided with a 1st delay circuit 3A delaying a 1st output signal OUT1 by a delay time (d 1 ) set by a 1st delay time control signal DTC 1 , and outputting a 1st delay signal V 2 and with a 2nd delay circuit 3B delaying a 2nd output signal OUT2 by a delay time (d 2 ) set by a 2nd delay time control signal DTC 2 , and outputting a 2nd delay signal V 3 . Then the delay time of 1st and 2nd delay circuits 3A, 3B delaying output signals of 1st and 2nd logic gate circuits 1A, 1B by a prescribed time and feeding back the signal to the input side of the 2nd and 1st logic gate circuits 1A is controlled by a delay time control signal. Thus, the time for a period when active levels of the 1st and 2nd output signals are not overlapped is selected. COPYRIGHT: (C)1991,JPO&Japio

Delay analysis for Datapac - a packet switched network with two priority classes

Abstract: Datapac is the public, packet-switched data communication network recently introduced into service by the Trans-Canada Telephone System. It supports two distinct categories of services - 'priority' and 'normal', where the priorities are user assigned. The delay performance for the Datapac services is specified in terms of the 'average delay' as well as '90th percentile delay' for priority and normal class packets. This paper presents some queueing models for estimating packet delays in the communication subnetwork of Datapac. The models can be applied for analyzing the sensitivity of packet delays to changes in such system parameters as: link capacities, link occupancies, relative packet lengths for priority and normal class packets and relative mix of priority and normal class packets.

Electric current switchover type flippflop circuit

Abstract: PURPOSE:To remove transient noise caused in low level output at clock switching, without sacrificing transmission delay time.

Priority control data transmission system

Abstract: PURPOSE:Effective prevention of the drop of transmission efficiency due to the increase of transmission delay by confining the priority control between each office and its preceeding office.

Introduction to Packet Switching

Abstract: The first network developments were an extension of the input-output system of the computer. They acted simply as a distribution network for a central computer. Figure 1 illustrates the forms that they took, in particular the multidrop line and then the concentrator which, by applying some intelligence remotely, can reduce the overhead traffic on the main lines to the centre. In the more elaborate versions the concentrators themselves form a multidrop configuration.

Remote monitor control sytem

Abstract: PURPOSE:To transmit commands in parallel with on-off control, by eliminating the transmission delay of on-off control in command transmission.