Frequency management system

• US 5,142,691 A
• Filed: 04/05/1991
• Issued: 08/25/1992
• Est. Priority Date: 04/05/1991
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Whitney, Susan M., Freeburg, Thomas A.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): BELZER, CHRISTINE
• Application Number:
  US07/681,813
• Time in Patent Office: 508 Days
• Field of Search: 455/63, 455/34, 455/33, 455/53, 455/54, 455/57, 455/71, 455/56, 455/62, 455/38, 455/58, 455/78, 455/88, 379/63, 340/825.47, 340/825.48, 340/825.5, 340/825.06
• US Class Current: 455/63.3
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A wireless RF communication system that shares frequency assignment with existing RF systems scans a set of possible operating frequencies for signals transmitted by the other systems. This data is sent to a frequency management center where a safe operating frequency is assigned. The new RF system periodically scans the set of frequencies and will automatically inhibit transmissions if a signal from another system is detected which exceeds a threshold, thereby indicating that a possibility exists for interference.

Claims

1. A method for minimizing radio frequency interference between a first set of wireless communications equipment operating in a range of frequencies and a second set of wireless communications equipment having a transmitter and receiver operating in said range of frequencies comprising the steps of:

said transmitter of the second set of communications equipment being locked in an inoperative mode until it receives a predetermined password;

said receiver of the second set of communications equipment scanning a predetermined set of frequencies within said range at its intended location of operation and storing a table of values corresponding to signals sensed during said scanning;

communicating said table of values and said location to a frequency management control center having frequency usage and location data for said first and second sets of communication equipment;

comparing said table of values and receiver location with said control center data;

assigning a frequency of operation for said transmitter to minimize the possibility of interference based on said comparison;

said control center generating said predetermined password and communicating it and said assigned frequency of operation to said transmitter;

whereby said transmitter is unlocked and can begin transmissions.

2. The method according to claim 1 further comprising the steps of said receiver of the second set of communications equipment periodically scanning said set of frequencies and generating new values corresponding to previously stored values for each frequency.

3. The method according to claim 2 further comprising the steps of locking said transmitter in an inoperative mode if a new value compared to the corresponding previously stored value reaches a predetermined threshold indicative of a greater probability of interference, and storing said new values.

4. The method according to claim 3 further comprising the steps of communicating said table of values including said new values to said control center, comparing said table of values and receiver location with said control center data, assigning a frequency of operation for said transmitter to minimize the possibility of interference based on said comparison, said said control center generating said predetermined password and communicating it and said assigned frequency of operation to said transmitter thereby unlocking said transmitter.

5. A wireless communications system for minimizing radio frequency interference between a first set of wireless communications equipment operating in a range of frequencies and a second set of wireless communications equipment having a transmitter and receiver operating in said range of frequencies, the system comprising:

means for locking said transmitter of the second set of communications equipment in an inoperative mode until it receives a predetermined password;

said receiver of the second set of communications equipment including means for scanning a predetermined set of frequencies within said range at its intended location of operation and storing a table of values corresponding to signals sensed during said scanning;

means for communicating said table of values and said location to a frequency management control center having frequency usage and location data for said first and second sets of communication equipment;

means for comparing said table of values and receiver location with said control center data;

means for assigning a frequency of operation for said transmitter to minimize the possibility of interference based on said comparison;

said control center including means for generating said predetermined password and communicating it and said assigned frequency of operation to said transmitter, thereby unlocking said transmitter and permitting it to begin transmissions.

6. The system according to claim 5 further comprising said receiver of the second set of communications equipment including means for periodically scanning said set of frequencies and generating new values corresponding to previously stored values for each frequency.

7. The system according to claim 6 further comprising means for locking said transmitter in an inoperative mode if a new value compared to the corresponding previously stored value reaches a predetermined threshold indicative of a greater probability of interference, and means for storing said new values.

8. The system according to claim 7 further comprising said communicating means communicating said table of values including said new values to said control center, said comparing means comparing said table of values and receiver location with said control center data, said assigning means assigning a frequency of operation for said transmitter to minimize the possibility of interference based on the most recent comparison, said control center generating means generating said predetermined password and communicating it and said assigned frequency of operation to said transmitter thereby unlocking said transmitter.

9. A wireless radio frequency transceiver having a transmitter and receiver comprising:

means for inhibiting said transmitter until a predetermined password is received;

means for scanning a predetermined set of possible operating frequencies with said transceiver at its intended location of operation;

means for storing a table of values corresponding to signals sensed at each scanned frequency;

means for enabling said table of values and said location to be communicated to a frequency management control center having frequency usage and location data for a geographic area that includes the location of said transceiver;

means for receiving said predetermined password generated by the control center and a command identifying a frequency of operation assigned by the control center;

means for unlocking said transmitter and permitting it to begin transmissions upon receipt of said password and command.

10. The transceiver according to claim 9 wherein said scanning means periodically scans said set of frequencies and generating new values corresponding to previously stored values for each scanned frequency.

11. The transceiver according to claim 10 wherein said inhibiting means relocks said transmitter in an inoperative mode if a new value compared to the corresponding previously stored value reaches a predetermined threshold indicative of a greater probability of interference, said storing means also storing said new values.

12. The transceiver according to claim 11 wherein said enabling means enables said table of values including said new values to be communicated to the control center, said unlocking means unlocking said transmitter and permitting it to begin transmissions upon receipt of said password and command from the control center.