US 5,537,549 A · Communication network with time coordinated station activity by time slot and periodic interval number

Abstract

Activity on a digital communication network is divided into periodic intervals and during a segment of each periodic interval a moderator station broadcasts a numerical count of the periodic intervals to all stations on the network. Each station has a memory in which a numerical value is stored, and a comparator that compares the numerical value to the numerical count received from the network. When the numerical count of the periodic intervals equals the numerical value, an apparatus within the station performs a defined operation, such as transmitting a message over the network or synchronizing a clock in the station to a master time standard. The equality of the periodic interval count and the numerical value also can be used to determine when to signal an external device. By using the count of the periodic intervals in this manner, the operation of several stations on the network can be coordinated.

Claims10

Dependent claims

A communication network comprising:

a medium through which messages can be transmitted by a plurality of stations during each one of a plurality of periodic intervals, in which the periodic intervals are numbered consecutively according to a predetermined modulus, and in which each periodic interval has a fixed, predetermined duration and includes a set of time slots during which stations are afforded an opportunity to transmit, wherein each time slot is identified by an associated slot number, with the slot number being included in the transmission made during each time slot to thereby identify the current time slot;
a first station which is connected to said medium, and which at a fixed, predetermined point during each periodic interval, transmits through said medium a moderator message which includes a periodic interval number in addition to the slot number, in which the periodic interval number represents a current value for the consecutive numbering of the periodic intervals;
and
a second station including a receiver coupled to said medium to receive transmissions made by other stations, the second station including:
a memory for storing a predefined value corresponding to one or more periodic interval numbers of interest;
a comparator connected to the receiver and the memory for comparing the periodic interval number from a received moderator message to the predefined value;
and
means connected to the comparator for performing a defined operation when the periodic interval number from a received moderator message equals the predefined value.

5 more elements

A media access controller for a communication network in which activity on the communication network is divided into a succession of periodic intervals which are numbered consecutively according to a predetermined modulus, and in which each periodic interval has a fixed, predetermined duration and includes a set of time slots during which each one of a plurality of stations are sequentially afforded an opportunity to transmit, wherein each time slot is identified by an associated slot number, with the slot number being included in the transmission made during each time slot to thereby identify the current time slot, and during each periodic interval a network moderator station transmits a moderator message containing a periodic interval number in addition to the slot number, in which the periodic interval number represents a current value for the consecutive numbering of the periodic intervals, said media access controller comprising:

an interface for connecting to an external data processing device to exchange data therebetween;
a receiver connected to the communication network to receive messages therefrom;
a first register connected to said receiver for storing the periodic interval number obtained from each successively received moderator message;
a memory for storing an outgoing data packet received from the external processing device, and a specified count corresponding to a future periodic interval during which the outgoing data packet is to be transmitted;
a transmitter connected to said interface and to said memory for sending the data message over the communication network;
and
an access control circuit which is connected to said transmitter, the first register and the memory, and which enables said transmitter to send data over the communication network when the periodic interval number in the first register equals the specified count for transmitting the outgoing data message.

4 more elements

Dependencies are inferred from the claim text.

Communication network with time coordinated station activity by time slot and periodic interval number

Life of this patent

Communication network with time coordinated station activity by time slot and periodic interval number

Life of this patent

Abstract

Claims10