Adaptive time-division multiplexing communications protocol method and system

• US 5,621,735 A
• Filed: 02/28/1996
• Issued: 04/15/1997
• Est. Priority Date: 08/13/1992
• Status: Expired due to Fees

• Current Assignee: UTICS Corporation
• Original Assignee: UTICS Corporation
• Inventors: Weaver, John D., Rochester, Virgil M. Jr., Jonson, Charles S., Hunt, Ariel M.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Patel, Ajit
• Application Number:
  US08/608,131
• Time in Patent Office: 412 Days
• Field of Search: 370/95.1, 370/95.2, 370/95.3, 370/60, 370/94.1, 370/94.2, 370/110.1, 370/85.6, 370/85.8, 340/825.08, 340/825.5, 340/825.51, 340/825.52, 379/91, 379/106
• US Class Current: 370/346
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

A system and method for an adaptive time-division multiplexing communications protocol for collecting data from remote sensors equipped with RF transceivers using an RF transceiver equipped mobile data collection unit. RF transceivers interfaced to remote sensors actively monitor a predetermined RF transmission frequency to ascertain the presence of a signal transmitted by the mobile unit. All remote units detecting the RF signal listen for a message from the mobile unit requesting transmission of their unique identifier, i.e., their ID. This message contains the Time Division Base (TDB) specifying the number of time slots allocated for transmission of remote sensor IDs to the mobile unit. Using the TDB, each remote sensor randomly selects a time slot and transmits its ID to the mobile unit. Unique IDs of remote sensors received by the mobile unit are used to individually poll each sensor for data packet transmission. Upon receipt of a data packet from a remote sensor, the mobile unit sends an acknowledgment packet indicating its data has been received. Upon receipt of the acknowledgment packet, the sensor is set to a state whereby it will not respond to a request for identifier for a specified period of time.

Claims

1. A communication protocol method for communicating data between a central unit and a plurality of remote units, the method comprising the steps of:

transmitting a first signal from said central unit within a transmission range;

receiving the first signal by remote units within the transmission range of the first signal;

transmitting first response signals from remote units which received the first signal, in response to the receipt of the first signal;

receiving first response signals by the central unit;

transmitting a second signal from sad central unit to each remote unit from which one of the first response signals was received;

receiving the second signal by remote units to which the second signal was sent;

transmitting a data signal from each remote unit which received the second signal to said central unit, in response to the receipt of the second signal;

receiving data signals by said central unit;

wherein the second signal includes control data for controlling the remote units, wherein the control data includes data for controlling at least one of the signal frequency of the data signal to be sent by the remote units, the data format and the type of data to be included in the data signal.

2. A communication protocol method for communicating data between a central unit and a plurality of remote units, the method comprising the steps of:

transmitting a first signal from said central unit within a transmission range;

receiving the first signal by remote units within the transmission range of the first signal;

transmitting first response signals from remote units which received the first signal, in response to the receipt of the first signal;

receiving first response signal by the central unit;

transmitting a second signal from said central unit to each remote unit from which one of the first response signals was received;

receiving the second signal by remote units to which the second signal was sent;

transmitting a data signal from each remote unit which received the second signal to said central unit, in response to the receipt of the second signal;

receiving data signals by said central unit;

wherein the second signal includes control data for altering the signal frequency of the data signal to be sent by one of the remote units.