Data transmission device, system and method

• US 5,383,134 A
• Filed: 05/23/1994
• Issued: 01/17/1995
• Est. Priority Date: 12/28/1992
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Wrzesinski, Stanley
• Primary Examiner(s): Voeltz, Emanuel T.
• Assistant Examiner(s): SHAH, KAMINI S
• Application Number:
  US08/247,621
• Time in Patent Office: 239 Days
• Field of Search: 340/870.03, 340/870.06, 340/870.011, 340/875.54, 364/514, 364/464.04, 364/492, 364/516, 364/514
• US Class Current: 340/870.03
• CPC Class Codes: G08C 15/00 Arrangements characterised by the use of multiplexing for the transmission of a plurality of signals over a common path

Abstract

A data transmission device (11; 111,) for use in a system (10) comprising a plurality of such devices is described along with a corresponding method of data transmission. A data signal (at 23) is provided for transmission and a timer apparatus (16, 18; 16, 118, 160) establishes a sequence of maximum time intervals (6 hours; 6 hours and 20 seconds) during which the data signal can be transmitted. A transmitter (18, 24, 25; 118, 24, 25) transmits the data signal during each of these maximum time intervals. The timer apparatus (16, 18; 16, 118, 160) generates a random number (steps 33, 54; steps 172, 195) for each one of the maximum time intervals, and the transmitter (18, 24, 25; 118, 24, 25) determines the transmission times for the data signal in accordance with the random numbers provided for each of these maximum time intervals. Preferably, the data transmission devices are part of a data transmission system (10) which includes a data receiver (12), and the data signal is obtained from and corresponds to the output of a utility meter (13). By utilization of random numbers to randomize the transmit times of the transmission devices, the probability that data transmissions from one transmission device will interfere with data transmissions from another device is substantially minimized.

Claims

1. Data transmission device for use in a system comprising a plurality of such data transmission devices, said data transmission device comprising:

means for providing a data signal for transmission;

timer means for establishing, in response to an initial power on signal received by the device, a continuous sequence of maximum time intervals during which said data signal can be transmitted; and

means for transmitting said data signal at a transmission time during each of said maximum time intervals;

said timer means including a random number generator for providing a random number for each of said maximum time intervals, said transmitting means determining the transmission time for said data signal during each of said maximum time intervals in accordance with said one of said random numbers provided for said each of said maximum time intervals;

wherein each of said maximum time intervals comprises a fixed time interval plus a variable time interval, said variable time interval being determined in accordance with said random number provided for each of said maximum time intervals, and said fixed time interval is at least one order of magnitude greater than said variable time interval, and said transmission times occur in accordance with said variable time intervals.

2. A data transmission device according to claim 1 wherein said data transmission device, said timer means, said maximum time intervals, said random number generator and, said transmission times provided for the data transmission device are independent of the operation of other of such data transmission devices.

3. A data transmission device according to claim 1 wherein said timer means comprises a fixed time interval means for establishing a fixed time interval, and wherein said maximum time intervals are determined in accordance with said fixed time interval.

4. A data transmission device according to claim 1 wherein each of said maximum time intervals are equal in duration and correspond to a fixed time interval.

5. A data transmission device according to claim 1 wherein said fixed time interval is at least two orders of magnitude greater than said variable time interval.

6. A data transmission device according to claim 1 wherein said transmitting means includes means for transmitting said data signal via wireless signal radiation.

7. A data transmission device according to claim 6 wherein said data signal providing means includes a utility meter means and said data signal is indicative of the use of a utility as measured by said utility meter means.

8. A data transmission device according to claim 1 wherein said data signal providing means includes a utility meter means and said data signal is indicative of the use of a utility as measured by said utility meter means.

9. A data transmission system comprising;

a plurality of data transmission devices each independently operative for transmitting its own data signal and;

a data receiver means for receiving the transmitted data signals from each of said plurality of data transmission devices;

each of said data transmission devices comprising;

means for providing a data signal for transmission;

timer means for establishing, in response to an initial power on signal received by the device, a continuous sequence of maximum time intervals during which said data signal can be transmitted; and

means for transmitting said data signal at a transmission time during each of said maximum time intervals;

said timer means including a random number generator for providing a random number for each of said maximum time intervals, said transmitting means determining the transmission time for said data signal during each of said maximum time intervals in accordance with said one of said random numbers provided for said each of said maximum time intervals;

Wherein each of said maximum time intervals comprises a fixed time interval plus a variable time interval , said variable time interval being determined in accordance with said random number provided for said maximum time interval, and said fixed time interval is at least one order of magnitude greater than said variable time interval, and said transmission times occur in accordance with said variable time intervals.

10. A data transmission system according to claim 9 wherein said data transmission devices, said timer means, said maximum time intervals, said random number generator and Said transmission times provided for each data transmission device are independent of the operation of other of said data transmission devices.

11. A data transmission system according to claim 9 wherein said timer means comprises a fixed time interval means for establishing a fixed time interval, and wherein said maximum time intervals are determined in accordance with said fixed time interval.

12. A data transmission system according to claim 9 wherein each of said maximum time intervals are equal in duration and correspond to a fixed time interval.

13. A data transmission system according to claim 9 wherein said transmitting means includes means for transmitting said data signal via wireless signal radiation.

14. A data transmission system according to claim 9 wherein said data signal providing means includes a utility meter means and said data signal is indicative of the use of a utility as measured by said utility meter means.

15. Data transmission method comprising the steps of;

providing a data signal for transmission,

establishing, in response to an initial received power on signal, a continuous sequence of maximum time intervals during which said data signal will be transmitted;

transmitting said data signal at a transmission time during each of said maximum time intervals; and

providing a random number for each of said maximum time intervals;

wherein said step of transmitting said data signal includes the step of determining the transmission time during each said maximum time intervals in accordance with said random number provided for said each of said maximum time intervals; and

each of said maximum time intervals comprises a fixed time interval plus a variable time interval, said variable time interval being determined in accordance with said random number provided for said maximum time interval, and wherein said fixed time interval is at least one order of magnitude greater than said variable time interval, and wherein said transmission times occur in accordance with said variable time intervals.

16. A data transmission method according to claim 15 wherein said step of establishing said maximum time intervals comprises establishing a fixed time interval, and determining said maximum time intervals in accordance with said fixed time interval.

17. A data transmission method according to claim 15 wherein each of said maximum time intervals are equal in duration and correspond to a fixed time interval.

18. A data transmission method according to claim 15 wherein said transmitting step includes the steps of transmitting said data signal via wireless signal radiation.

19. A data transmission method according to claim 15 wherein said data signal providing step includes the step of providing a utility meter means and wherein said data signal is indicative of the use of a utility as measured by said utility meter means.

20. Data transmission device for use in a system comprising a plurality of such data transmission devices, said data transmission device comprising:

means for providing a data signal for transmission;

timer means for establishing, in response to an initial power on signal received by the device, a continuous sequence of maximum time intervals during which said data signal can be transmitted; and

means for transmitting said data signal at a transmission time during each of said maximum time intervals;

said timer means including a random number generator for providing a random number for each of said maximum time intervals, said transmitting means determining the transmission time for said data signal during each of said maximum time intervals in accordance with said one of said random numbers provided for said each of said maximum time intervals;

plus a variable time interval, said variable time interval being determined in accordance with said random number provided for each of said maximum time intervals, said variable time interval being determined by a microprocessor which utilizes said random numbers to provide said variable time interval, and said fixed time interval provided by a fixed time interval circuit external to said microprocessor, and said transmission times occur in accordance with said variable time intervals.

21. A data transmission device according to claim 20 wherein said fixed time interval is at least one order of magnitude greater than said variable time interval.

22. A data transmission system comprising;

a plurality of data transmission devices each independently operative for transmitting its own data signal and;

a data receiver means for receiving the transmitted data signals from each of said plurality of data transmission devices;

each of said data transmission devices comprising;

means for providing a data signal for transmission;

timer means for establishing, in response to an initial power on signal received by the device, a continuous sequence of maximum time intervals during which said data signal can be transmitted; and

means for transmitting said data signal at a transmission time during each of said maximum time intervals;

said timer means including a random number generator for providing a random number for each of said maximum time intervals, said transmitting means determining the transmission time for said data signal during each of said maximum time intervals in accordance with sad one of said random numbers provided for said each of said maximum time intervals;

wherein each of said maximum time intervals comprises a fixed time interval plus a variable time interval, said variable time interval being determined in accordance with said random number provided for each of said maximum time intervals, said variable time interval being determined by a microprocessor which utilizes said random numbers to provide said variable time interval, and said fixed time interval provided by a fixed time interval circuit external to said microprocessor, and said transmission times occur in accordance with said variable time intervals.

23. A data transmission system according to claim 22 wherein said fixed time interval is at least one order of magnitude greater than said variable time interval.

24. Data transmission method comprising the steps of;

providing a data signal for transmission,

establishing, in response to an initial received power on signal, a continuous sequence of maximum time intervals during which said data signal will be transmitted;

transmitting said data signal at a transmission time during each of said maximum time intervals; and

providing a random number for each of said maximum time intervals;

wherein said step of transmitting ;

said data signal includes the step of determining the transmission time during each said maximum time intervals in accordance with said random number provided for said each of said maximum time intervals, and wherein each of said maximum time intervals comprises a fixed time interval plus a variable time interval, said variable time interval being determined in accordance with said random number provided for each of said maximum time intervals, said variable time interval being determined by a microprocessor which utilizes said random numbers to provide said Variable time interval, and said fixed time interval provided by a fixed time interval circuit external to said microprocessor, and wherein said transmission times occur in accordance with said variable time intervals.

25. A data transmission method according to claim 30 wherein said fixed time interval is at least one order of magnitude greater than said variable time interval.