Method and system for autonomously allocating a frequency hopping traffic channel in a private radio system

• US 6,351,643 B1
• Filed: 07/16/1999
• Issued: 02/26/2002
• Est. Priority Date: 08/28/1996
• Status: Expired due to Term

• Current Assignee: Blackberry Limited
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Haartsen, Jacobus C.
• Primary Examiner(s): Chang, Vivian
• Assistant Examiner(s): APPIAH, CHARLES NANA
• Application Number:
  US09/369,976
• Time in Patent Office: 956 Days
• Field of Search: 455/450, 455/444, 455/451, 455/452, 455/464, 455/509, 455/513, 455/62, 455/63, 370/329, 370/330, 370/333
• US Class Current: 455/450
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/16 for PBS [Private Base Station] arrangements
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 84/105 PBS [Private Base Station] network H04W84/12 - H04W84/16 take precedence

Abstract

An allocation method and system for allocating a least-interfered communications link between a cellular mobile station and a private radio base station within a cellular system is disclosed. A set of candidate carrier frequencies are first selected and ordered by the amount of interference present within the cellular system, and a subset thereof selected. A second set of candidate frequencies and associated timeslots are then selected from the subset and ordered by the amount of interference present in the private radio system environment, and a second subset thereof selected. A plurality of discrete hop lists for each timeslot are then formed, and one of the hop lists exhibiting the least amount of interference is then selected to be applied in the communications link.

Claims

1. A method for determining candidate frequencies for minimizing interference in a communications link between a private radio system and an overlaying communications system, said method comprising the steps of:

identifying a plurality of frequencies usable by the private radio system;

performing a first plurality of measurements on each frequency of said plurality of frequencies;

averaging said first plurality of measurements for said each frequency over a first time period;

creating a first ordered list of frequencies based on said averaged first plurality of measurements, wherein said first ordered list of frequencies is arranged according to an amount of interference indicated by said averaged first plurality of measurements;

selecting a subset list from said first ordered list of frequencies, wherein said subset list contains frequencies having a lower amount of interference relative to frequencies not selected for said subset list from said first ordered list of frequencies;

averaging a second plurality of measurements for each frequency in said subset list, wherein said second plurality of measurements corresponds to a second time period smaller than said first time period;

creating a second ordered list of frequencies based on said averaged second plurality of measurements, wherein said second ordered list of frequencies is arranged according to an amount of interference indicated by said averaged second plurality of measurements;

selecting a set of optimal frequencies from said second ordered list of frequencies, wherein said set of optimal frequencies include frequencies from said second ordered list of frequencies having a lower amount of interference relative to frequencies not selected for said set of optimal frequencies from said second ordered list of frequencies; and

generating a plurality of discrete hop lists from said set of optimal frequencies.

2. The method of claim 1, wherein said first time period is selected from the group consisting of a plurality of hours and a plurality of days.

3. The method of claim 1, wherein said second time period is selected from the group consisting of a period of minutes and a period of seconds.

4. The method of claim 1, wherein said step of generating a plurality of discrete hop lists further comprises the steps of:

performing active measurements on each of said optimal frequencies;

averaging said active measurements for each of said optimal frequencies over a third time period smaller than said second time period;

ordering said set of optimal frequencies into a preferred list of candidate frequencies based on said averaged active measurements; and

generating said plurality of discrete hop lists from said preferred list.

5. The method of claim 1, wherein each said discrete hop list comprises:

a group of frequency/timeslot pairs, said group including a plurality of frequency/timeslot pairs each selected from said set of optimal frequencies and each having the same timeslot.

6. The method of claim 5, further comprising the step of:

selecting one of said plurality of discrete hop lists for establishing a communications link, said one of said plurality of discrete hop lists including a second plurality of frequencies having one associated timeslot.

7. The method of claim 1, wherein said step of identifying said plurality of frequencies comprises the step of:

downloading an identification of said plurality of frequencies to said private radio system from the overlaying communications system.

8. The method of claim 1, wherein said step of identifying said plurality of frequencies comprises the step of:

preprogramming said private radio system with an identification of said plurality of frequencies at a time of manufacturing.

9. The method of claim 1, wherein said step of identifying a plurality of frequencies further comprises the step of:

adapting said identified plurality of frequencies according to changes in a cellular reuse plan.

10. A method for determining candidate frequencies for minimizing interference in a communications link between a private radio system and an overlaying communications system, said method comprising the steps of:

identifying a plurality of frequencies usable by the private radio system;

performing a plurality of measurements on each frequency of said plurality of frequencies;

averaging said plurality of measurements for said each frequency over a first time period comprising a long-term duration;

creating a first ordered list of frequencies based on said averaged plurality of measurements, wherein said first ordered list of frequencies is arranged according to an amount of interference indicated by said averaged plurality of measurements;

selecting a subset list from said first ordered list of frequencies, wherein said subset list contains frequencies having a lower amount of interference relative to frequencies not selected for said subset list from said first ordered list of frequencies;

averaging a subset of measurements for each timeslot associated with each frequency in said subset list, wherein said subset of measurements corresponds to a second time period smaller than said first time period;

creating a second ordered list of frequencies and associated timeslots based on said averaged subset of measurements, wherein said second ordered list of frequencies and associated timeslots is arranged according to an amount of interference indicated by said averaged subset of measurements;

selecting a set of optimal frequency and timeslot pairings from said second ordered list of frequencies and associated timeslots, wherein said set of optimal frequency and timeslot pairings include frequencies and associated timeslots having a lower amount of interference relative to frequencies not selected for said set of optimal frequency and timeslot pairings from said second ordered list of frequencies and associated timeslots;

generating a plurality of discrete hop lists from said set of optimal frequency and timeslot pairings.

11. The method of claim 10, wherein said step of generating a plurality of discrete hop lists further comprises the steps of:

performing active measurements on each of said optimal frequency and timeslot pairings;

averaging said active measurements for each of said optimal frequency and timeslot pairings over a third time period smaller than said second time period;

ordering said set of optimal frequency and timeslot pairings into a preferred list of candidate frequencies based on said averaged active measurements; and

generating a plurality of discrete hop lists from said preferred list.

12. The method of claim 10, wherein said step of generating said discrete hop lists comprises the step of:

grouping at least two of said frequency and timeslot pairings having the same timeslot into one of said plurality of discrete hop lists.

13. The method of claim 12, further comprising the step of:

selecting one of said plurality of discrete hop lists for establishing a communications link, said selected discrete hop list including a plurality of frequency and timeslot pairings having the same associated timeslot.

14. The method of claim 10, wherein said first time period is selected from the group consisting of a plurality of hours and a plurality of days.

15. The method of claim 10, wherein said second time period is selected from the group consisting of a period of minutes and a period of seconds.

16. The method of claim 10, wherein said plurality of measurements on each said frequency comprise at least one measurement on a first timeslot and at least one measurement on a second timeslot, wherein said timeslot measurements on each said frequency are averaged together to generate said averaged plurality of measurements.

17. The method of claim 10, wherein at least two timeslots from said second ordered list of frequencies and associated timeslots, each of said at least two timeslots associated with the same frequency, are measured and averaged separately of each other.

18. A method for determining candidate frequencies for minimizing interference in a communications link between a private radio system and an overlaying communications system, said method comprising the steps of:

performing measurements on a plurality of frequencies usable by the private radio system;

averaging said measurements of said plurality of frequencies, said averaged measurements indicative of an amount of interference for each of said plurality of frequencies in said private radio system;

creating an ordered list of candidate frequencies based on said averaged measurements;

generating an ordered set of frequency/timeslot pairings, each frequency of said set of frequency/timeslot pairings derived from said ordered list of candidate frequencies, each timeslot of said set of frequency/timeslot pairings associated with multiple frequencies from said ordered list of candidate frequencies, said ordered list of frequency/timeslot pairings based on an amount of interference associated with each frequency/timeslot pairing; and

selecting at least one frequency/timeslot pairing from said ordered set of frequency/timeslot pairings for use in establishing a communication link, said at least one frequency/timeslot pairing selected based on the associated amount of interference.

19. The method of claim 18, further comprising, before said step of generating, the steps of:

performing second measurements on said each timeslot of said frequency/timeslot pairings; and

averaging said second measurements of said each timeslot.

20. The method of claim 18, further comprising the step of:

generating a plurality discrete hop lists, each of said plurality of discrete hop lists associated with a different timeslot, each said different timeslot associated with a second plurality of frequencies.

21. The method of claim 18, further comprising the step of:

measuring a quality of said communication link to inform a private radio base station of current interference conditions.

22. The method of claim 18, wherein said step of performing measurements further comprises the steps of:

performing first measurements in the uplink; and

performing second measurements in the downlink.

23. The method of claim 22, further comprising the step of:

combining said first measurement in the uplink and said second measurement in the downlink.

24. The method of claim 18, wherein said measurements on each said frequency comprise at least one measurement on a first timeslot and at least one measurement on a second timeslot, wherein said time slot measurements on each said frequency are averaged together to generate said averaged measurements.

25. The method of claim 18, wherein at least two timeslots from said ordered set of frequency/timeslot pairings, each of said at least two timeslots associated with the same frequency, are measured and averaged separately of each other.

26. A system for determining candidate frequencies for minimizing interference in a communications link in a communications system, said system comprising:

a Public Land Mobile Network; and

a private radio system at least partially overlapping with the Public Land Mobile Network, said private radio system operating to;

perform measurements on a plurality of frequencies usable by the private radio system;

average said measurements of said plurality of frequencies, said averaged measurements indicative of an amount of interference for each of said plurality of frequencies in said private radio system;

create an ordered list of candidate frequencies based on said averaged measurements;

generate an ordered set of frequency/timeslot pairings, each frequency of said set of frequency/timeslot pairings derived from said ordered list of candidate frequencies, each timeslot of said set of frequency/timeslot pairings associated with multiple frequencies from said ordered list of candidate frequencies, said ordered set of frequency/timeslot pairings based on an amount of interference associated with each frequency/timeslot pairing; and

select at least one frequency/timeslot pairing from said ordered set of frequency/timeslot pairings for use in establishing a communication link, said at least one frequency/timeslot pairing selected based on the associated amount of interference.

27. The system of claim 26, wherein, before operating to select at least one frequency/timeslot pairing, said private radio system further operates to:

perform second measurements on said each timeslot of said set of frequency/timeslot pairings; and

average said second measurements of said each timeslot.

28. The system of claim 26, wherein said private radio system further operates to:

generate a plurality discrete hop lists, each of said plurality of discrete hop lists associated with a different timeslot, each said different timeslot associated with a second plurality of frequencies.

29. The system of claim 28, wherein said private radio system further operates to:

select one of said plurality of discrete hop lists for use in establishing said communications link.