Rolling code security system

• US 7,623,663 B2
• Filed: 12/21/2005
• Issued: 11/24/2009
• Est. Priority Date: 05/17/1995
• Status: Expired due to Fees

• Current Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Original Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Inventors: Fitzgibbon, James J., Farris, Bradford L.
• Primary Examiner(s): Song; Hosuk
• Application Number:
  US11/313,331
• Publication Number:
  US 20060109978A1
• Time in Patent Office: 1,434 Days
• Field of Search: 380/262, 380/239, 380/44, 341/173, 340/825.72, 340/825.71, 340/825.73, 726 2- 4, 726 16- 17, 726 27- 30
• US Class Current: 380/239
• CPC Class Codes: G07C 2009/00214 by one push button
• CPC Class Codes: G07C 2009/0023 with encription of the transmittted data signal
• CPC Class Codes: G07C 2009/00238 the transmittted data signal containing a code which is changed
• CPC Class Codes: G07C 2009/00253 dynamically, e.g. variable code - rolling code
• CPC Class Codes: G07C 2009/00555 comprising means to detect or avoid relay attacks
• CPC Class Codes: G07C 2009/00587 by battery
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2009/00928 for garage doors
• CPC Class Codes: G07C 2209/06 Involving synchronization or resynchronization between transmitter and receiver; reordering of codes
• CPC Class Codes: G07C 2209/08 With time considerations, e.g. temporary activation, valid time window or time limitations
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: G07C 9/00817 where the code of the lock can be programmed
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 2209/84 Vehicles
• CPC Class Codes: H04L 9/3226 using a predetermined code, e.g. password, passphrase or PIN network architectures or network communication protocols for supporting authentication of entities using passwords in a packet data network H04L63/083
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

A rolling code transmitter is useful in a security system for providing secure encrypted RF transmission comprising an interleaved trinary bit fixed code and rolling code. A receiver demodulates the encrypted RF transmission and recovers the fixed code and rolling code. Upon comparison of the fixed and rolling codes with stored codes and determining that the signal has emanated from an authorized transmitter, a signal is generated to actuate an electric motor to open or close a movable barrier.

Claims

1. A security system for generating authorizing signals in response to transmitted rolling codes comprising:

a transmitter responsive to interaction with a send button for transmitting rolling codes comprising a fixed portion and a rolling portion which varies with each transmission in accordance with a predetermined sequence of rolling portions;

a receiver for receiving transmitted rolling codes and for learning the fixed portion and a first rolling portion of the sequence of rolling portions;

the receiver being responsive to a received rolling code for generating authorizing signals when the received rolling code comprises the previously learned fixed code portion and a rolling portion within a first predetermined number of rolling portions in the sequence of the learned rolling portion; and

the receiver being responsive to a received rolling code for generating authorizing signals when the received rolling code comprises the learned fixed code portion, the rolling code portion is beyond the first predetermined number of rolling portions and is within a second predetermined number of rolling portions of the rolling portion of a most recently received prior rolling code.

2. The security system of claim 1 wherein the receiver stores the rolling portion of the last received rolling code.

3. The security system of claim 1 wherein the receiver updates the learned rolling portion to the rolling portion of the most recently received rolling code which resulted in the generation of authorizing signals.

4. The security system of claim 1 comprising apparatus responsive to the authorizing signal controlling a barrier.

5. The security system of claim 1 wherein the receiver is associated with a vehicle.

6. A method of controlling the generation of authorizing signals in a security system in response to transmitted rolling codes comprising a fixed code portion and a rolling code portion, successive rolling code portions varying from the prior rolling code portion in a predetermined manner the method comprising:

receiving rolling codes;

first generating authorizing signals in response to a first received rolling code having a first fixed code portion and a rolling code portion which is within a first predetermined number of rolling code portions from the last rolling code which resulted in the generation of authorizing signals;

generating authorizing signals in response to a second rolling code having the first fixed code and a rolling code portion beyond the first predetermined number of rolling code portions from the last rolling code which resulted in the generation of authorizing signals when the rolling code portion of the second rolling code is successive to the rolling code portion of a first rolling code received immediately prior to the second rolling code.

7. The method of claim 6 comprising storing the rolling portion of the prior rolling code.

8. The method of claim 6 comprising learning the learned rolling of the most recently received rolling code which resulted in the generation of authorizing signals.

9. The method of claim 6 comprising controlling a barrier responsive to the authorizing signal.

10. The method of claim 6 comprising disposing the receiver with a vehicle.

11. A method of controlling the generation of authorizing signals in a security system in response to transmitted rolling codes comprising a fixed code portion and a rolling code portion, successive rolling code portions varying from the prior rolling code portions in a predetermined manner the method comprising:

learning a rolling code having a fixed portion and a rolling portion;

receiving, after the learning step, a first code comprising the learned fixed portion

and a first rolling portion and selectively generating an authorizing signal or not, based on a first determined relationship between the learned rolling portion and the first rolling portion;

receiving a second rolling code comprising the learned fixed portion, after receipt of the first rolling code;

generating an authorizing signal when the second rolling code comprises a rolling portion having a second predetermined relationship to the first rolling portion; and

updating the learned rolling portion when an authorizing signal is generated.

12. The method of claim 11 comprising storing the rolling portion of the previously received rolling codes.

13. The method of claim 11 comprising updating the learned rolling portion to the rolling portion of the most recently received rolling code which resulted in the generation of authorizing signals.

14. The method of claim 11 comprising controlling a barrier in response to the authorizing signal.

15. The method of claim 11 comprising disposing the receiver with a vehicle.