Method, device and data communication system for multilink polling

• US 5,805,586 A
• Filed: 05/02/1995
• Issued: 09/08/1998
• Est. Priority Date: 05/02/1995
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Perreault, John A., Joshi, Abhay, Schroeder, Stephen, Lloyd, Lawrence W., Kabatepe, Mete
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): RAO, SEEMA SRINIVAS
• Application Number:
  US08/433,877
• Time in Patent Office: 1,225 Days
• Field of Search: 370/95.2, 370/95.1, 370/85.1, 370/85.8, 370/94.3, 370/93, 370/95.3, 370/104.1, 370/449, 370/450, 370/451, 370/431, 370/432, 370/438, 370/439, 370/462, 370/447 , 370/537, 370/480, 370/312, 370/343-348, 340/825.07, 340/825.08
• US Class Current: 370/346
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling

Abstract

A control station (8) is coupled to a plurality of tributary devices (20, 16, 18) by way of at least one high speed broadcast downstream data channel and more than one shared lower speed upstream data channels. The control station (8) broadcasts data to all the tributary devices (20, 16, 18) and selects a channel for a specific tributary device (20, 16, 18) to respond to a poll. After polling, the tributary device (20, 16, 18) changes the tributary device transmitter (42) to the frequency of the selected channel. The tributary device (20, 16, 18) either sends data to send to the control station (8) or sends a negative acknowledge to the control station (8). If a negative acknowledgment was transmitted, the control station (8) notifies the control station transmitter that the channel is idle.

Claims

1. In a data communication system wherein a control station is coupled to a plurality of tributary devices by way of at least one high speed broadcast downstream data channel and more than one shared lower speed upstream data channels, each of the shared lower speed upstream data channels having a unique upstream channel frequency and a corresponding unique upstream channel identifier, a method for controlling access to the shared lower speed upstream data channels comprising the steps of:

selecting one of the tributary devices to be polled;

selecting one of the shared lower speed upstream data channels for transmission by the selected tributary device; and

sending from the control station to the selected tributary device a poll message including the unique upstream channel identifier corresponding to the selected shared lower speed upstream data channel.

2. The method of claim 1 further comprising the steps of:

receiving the poll message by the selected tributary device;

obtaining the unique upstream channel identifier for the selected shared lower speed upstream data channel from the poll message;

setting a tributary device transmitter to the unique upstream channel frequency of the selected shared lower speed upstream data channel; and

transmitting, by way of the tributary device transmitter, a response to the poll message on the selected shared lower speed upstream data channel.

3. In a data communication system wherein a control station is coupled to a plurality of tributary devices by way of at least one high speed broadcast downstream data channel and more than one shared lower speed upstream data channels, each of the shared lower speed upstream data channels having a unique upstream channel frequency and a corresponding unique upstream channel identifier, the control station comprising:

a control station poll processor for selecting a tributary device to be polled and for selecting one of the plurality of upstream data channels for transmission by the selected tributary device;

a control station transmitter for transmitting a poll message to the selected tributary device including a unique channel identifier for the selected channel; and

a control station receiver coupled to the selected channel for receiving transmission from the selected tributary device.

4. In a data communication system wherein a control station is coupled to a plurality of tributary devices by way of at least one high speed broadcast downstream data channel and more than one shared lower speed upstream data channels, each of the shared lower speed upstream data channels having a unique upstream channel frequency and a corresponding unique upstream channel identifier, a tributary device comprising:

a tributary device receiver for receiving a poll message including a unique upstream channel identifier;

a tributary device poll processor for processing the poll message;

a frequency selector coupled to the poll processor for tuning a tributary device transmitter to a unique upstream channel frequency corresponding to the unique upstream channel identifier; and

the tributary device transmitter for transmitting a response to the poll message.

5. A data communication system comprising:

a downstream channel;

a plurality of upstream channels, each having a unique upstream channel frequency and a corresponding unique upstream channel identifier;

a control station having a control station poll processor for selecting one of a number of tributary devices to be polled and for selecting one of the plurality of upstream channels for transmission by the selected tributary device, a control station transmitter coupled to the downstream channel for sending a poll message to the selected tributary device including a unique upstream channel identifier for the selected upstream channel, and a plurality of control station receivers, each coupled to one of the plurality of upstream channels; and

at least one tributary device having a tributary device receiver coupled to the downstream channel for receiving the poll message from the control station, a tributary device transmitter coupleable to each of the plurality of upstream channels for transmitting a response to the poll message, a poll processor coupled to the tributary device receiver for processing the poll message, and a frequency selector for tuning the tributary device transmitter to the unique upstream channel frequency corresponding to the unique upstream channel identifier.