Dynamic channel selection in a cellular communication system

• US 6,138,024 A
• Filed: 10/23/1997
• Issued: 10/24/2000
• Est. Priority Date: 10/23/1997
• Status: Expired due to Term

• Current Assignee: Allen Telecom LLC (CommScope Holding Company, Inc.)
• Original Assignee: Allen Telecom Inc. (CommScope Holding Company, Inc.)
• Inventors: Rubin, Eric, Evans, Michael W., Sihlanick, Mark
• Primary Examiner(s): Hunter, Daniel S.
• Assistant Examiner(s): Corsaro, Nick
• Application Number:
  US08/956,662
• Time in Patent Office: 1,097 Days
• Field of Search: 455/434, 455/452, 455/448, 455/426, 455/62, 455/400, 455/34.1
• US Class Current: 455/452.2
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A method of selecting allocated communication channels for use by a cellular auxiliary personal communication system (CAPCS) comprising periodically collecting relative signal strength indication (RSSI) measurements for all allocated communication channels, periodically determining the estimated expected probability of non-interference for each allocated communication channel based on the relative signal strength indication measurements and selecting an available allocated communication channel having the highest estimated expected probability of non-interference for use by the CAPCS system. The relative signal strength indication measurements are made on the allocated communication channels by measuring the signal on the allocated communication channel when no call is being carried by the CAPCS on that channel. The estimated expected probability of non-interference for each allocated communication channel also takes into consideration the received signal strength indication measurements on adjacent allocated communication channels and allocated communication channels in the same group.

Claims

1. In a first cellular communication system having a set of allocated communication channels for transmitting and receiving communication signals in a geographic area and in which a second cellular communication system has a set of assigned channels for transmitting and receiving in the same geographic area, some of said assigned channels being the same as said allocated communication channels, a method of selecting an available allocated communication channel for use in transmitting and receiving communication signals in said first cellular communication system, comprising the steps of:

in said first cellular communication system periodically sensing and measuring received signal strength indication data on each then available allocated communication channel;

storing said sensed and measured data for each allocated communication channel;

periodically determining from said stored sensed and measured data the estimated expected probability of non-interference for each allocated communication channel relative to others of said allocated communication channels;

selecting for use by said first cellular communication system an available allocated communication channel from said set of allocated communication channels based on the estimated expected probability of non-interference;

determining the occurrence of channel assignment changes in said second cellular communication system;

in response to said determination, suspending said selecting step, deleting said stored received signal strength indication data for all allocated communication channels, and, thereafter, reactivating said sensing, storing, determining and selecting steps.

2. The method of claim 1 wherein the selecting step comprises selecting an available allocated communication channel with the highest estimated expected probability of non-interference.

3. The method of claim 1 wherein the selecting step further comprises selecting an available allocated communication channel which is not adjacent to an allocated communication channel which is then in use by the first cellular communication system.

4. The method of claim 1 wherein:

the set of allocated communication channels is divided into a plurality of groups, and

wherein the estimated expected probability of non-interference for an allocated communication channel in a group is determined in part based on the received signal strength indication data for all allocated communication channels in said group.

5. The method of claim 4 wherein the estimated expected probability of non-interference for an allocated communication channel in said group is adjusted by a group improvement factor or a group degradation factor.

6. The method of claim 1 further comprising the steps of:

sensing and measuring said received signal strength indication data over a period of time and storing said sensed and measured data in an RSSI database; and

determining said estimated expected probability of non-interference for each allocated communication channel based upon at least a portion of said stored data.

7. The method of claim 1 further comprising the step of:

suspending said periodic sensing and measuring step during periods of low activity in said second cellular communication system.

8. The method of claim 1 and wherein said allocated communication channels include a plurality of allocated control channels and comprising the step of:

periodically determining from said stored sensed and measured data the estimated expected probability of non-interference for each available allocated control channel.

9. The method of claim 8 wherein said plurality of allocated control channels include one allocated control channel in use by said first cellular communication system and at least one available allocated control channel;

and

during its period of use, suspending the periodic sensing and measuring step for said one allocated control channel.

10. The method of claim 9 further comprising the step of periodically replacing in said first cellular communication system said one allocated control channel with an available allocated control channel based on the estimated expected probability of non-interference of the available allocated control channels.

11. The method of claim 1 wherein the estimated expected probability of non-interference for an allocated communication channel is based on the received signal strength indication data for the allocated communication channel, on the received signal strength indication data for the allocated communication channel adjacent to and above the allocated communication channel and on the received signal strength indication data for the allocated communication channel adjacent to and below the allocated communication channel.

12. The method of claim 1 wherein the estimated expected probability of non-interference for each allocated communication channel is determined according to the following formula:

space="preserve" listing-type="equation">HLEPNI.sub.x =HEPNI.sub.x *AHEPHI.sub.x-1 *AHEPNI.sub.x+1 *LEPNI.sub.x *ALEPNI.sub.x-1 *ALEPNI.sub.x+1

WHERE;

HLEPNI_x is the estimated expected probability of non-interference (EPNI) for allocated communication channel X;

HEPNI_x is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on allocated communication channel X;

AHEPNI_x-1 is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on the adjacent allocated communication channel below allocated communication channel X;

AHEPNI_x+1 is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on the adjacent allocated communication channel above allocated communication channel X;

LEPNI_x, is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on allocated communication channel X;

ALEPNI_x-1 is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on the adjacent allocated communication channel below allocated communication channel X; and

ALEPNI_x+1 is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on the adjacent allocated communication channel above allocated communication channel X.

13. The method of claim 1 wherein said first cellular communication system comprises a cellular auxiliary personal communication system and said second cellular communication system comprises a convention cellular communication system.

14. In a first cellular communication system having a set of allocated communication channels for transmitting and receiving communication signals in a geographic area and in which a second cellular communication system has a set of assigned channels for transmitting and receiving in the same geographic area, some of said assigned channels being the same as said allocated communication channels, the allocated communication channels including allocated voice channels and allocated control channels, a method of selecting an available allocated communication channel for use in transmitting and receiving communication signals in said first cellular communication system, comprising the steps of:

in said first cellular communication system, periodically collecting received signal strength indication measurements on each then available allocated communication channel over an extended period of time and storing said measurements in an RSSI database;

periodically determining the estimated expected probability of non-interference for each allocated communication channel based upon at least a portion of said collected and stored received signal strength indication measurements;

selecting for use by said first cellular communication system an available allocated communication channel having the highest estimated expected probability of non-interference;

determining channel assignment changes in said second cellular communication system;

in response to said determination, suspending said selecting step and

deleting said recorded received signal strength indication measurements for all allocated communications channels from said RSSI database and then reactivating said collecting, determining and selecting steps.

15. The method of claim 14 wherein the selecting step further comprises selecting an available allocated communication channel with the highest estimated expected probability of non-interference and which is not adjacent to an allocated communication channel then in use by the first cellular communication system.

16. The method of claim 14 wherein the set of the allocated communication channels is divided into a plurality of groups, and wherein:

the estimated expected probability of non-interference for an allocated communication channel in a group is based in part on the received signal strength indication measurements for all allocated communication channels in said group.

17. The method of claim 16 wherein the estimated expected probability of non-interference for an allocated communication channel in said group is adjusted by a group improvement factor or a group degradation factor.

18. The method of claim 14 wherein said allocated voice channels comprise forward voice channels each operating on a first frequency split and reverse voice channels each operating on a second frequency split and wherein the step of periodically collecting further comprises:

collecting received signal strength indication measurements for each said reverse voice channel on each corresponding first frequency split; and

collecting received signal strength indication measurements for each said forward voice channel on each corresponding second frequency split;

wherein said estimated expected probability of non-interference for each allocated voice channel is based on said received signal strength indication measurements collected on said corresponding first and second frequency splits.

19. The method of claim 18 wherein said collected received signal strength indication measurements taken on each first frequency split are recorded over an extended period of time into a first split RSSI database and said collected received signal strength indication measurements taken on each second frequency split are recorded over an extended period of time into a second frequency split RSSI database;

and

said estimated expected probability of non-interference for each allocated voice channel is based upon at least a portion of said recorded first frequency split received signal strength indication measurements and at least a portion of said recorded second frequency split received signal strength indication measurements.

20. The method of claim 18 wherein said set of allocated voice channels are divided into a plurality of groups;

and

wherein the estimated expected probability of non-interference for an allocated voice channel in a group is based upon at least a portion of said recorded first frequency split received signal strength indication measurements and at least a portion of said recorded second frequency split received signal strength indication measurements for all allocated voice channels in said group.

21. The method of claim 14 further comprising the steps of:

suspending said periodic collecting step during periods of low activity in said second cellular communication system.

22. The method of claim 14 wherein said allocated control channels include one allocated control channel in use by said first cellular communication system and at least one available allocated control channel.

23. The method of claim 22 wherein said selecting step further comprises periodically replacing said one allocated control channel with an available allocated control channel based on the estimated expected probability of non-interference of the available allocated control channels.

24. The method of claim 14 wherein the estimated expected probability of non-interference for an allocated communication channel is based on the received signal strength indication measurements for the allocated communication channel, on the received signal strength indication measurements for an allocated communication channel adjacent to and above the allocated communication channel and on the received signal strength indication measurements for an allocated communication channel adjacent to and below the allocated communication channel.

25. The method of claim 14 wherein the estimated expected probability of non-interference for each allocated communication channel is determined according to the following formula:

space="preserve" listing-type="equation">HLEPNI.sub.x =HEPNI.sub.x *AHEPHI.sub.x-1 *AHEPNI.sub.x+1 *LEPNI.sub.x *ALEPNI.sub.x-1 *ALEPNI.sub.x+1

WHERE;

HLEPNI_x is the estimated expected probability of non-interference (EPNI) for allocated communication channel X;

HEPNI_x is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on allocated communication channel X;

AHEPNI_x-1 is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on the adjacent allocated communication channel below allocated communication channel X;

AHEPNI_x+1 is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on the adjacent allocated communication channel above allocated communication channel X;

LEPNI_x, is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on allocated communication channel X;

ALEPNI_x-1 is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on the adjacent allocated communication channel below allocated communication channel X; and

ALEPNI_x+1 is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on the adjacent allocated communication channel above allocated communication channel X.

26. The method of claim 14 wherein said first cellular communication system comprises a cellular auxiliary personal communication system and said second cellular communication system comprises a conventional cellular communication system.

27. In a first cellular communication system having a set of allocated communication channels for transmitting and receiving communication signals in a geographic area and in which a second cellular communication system has a set of assigned channels for transmitting and receiving in the same geographic area, some of said assigned channels being the same as said allocated communication channels, a method of selecting an available allocated communication channel for use in transmitting and receiving communication signals in said first cellular communication system, comprising the steps of:

in said first cellular communication system periodically sensing and measuring received signal strength indication data on each then available allocated communication channel;

storing said sensed and measured data for each allocated communication channel;

periodically determining from said stored sensed and measured data the estimated expected probability of non-interference for each allocated communication channels;

selecting for use by said first cellular communication system an available allocated communication channel from said set of allocated communication channels based on the estimated expected probability of non-interference;

wherein the estimated expected probability of non-interference for each allocated communication channel is determined according to the following formula;

space="preserve" listing-type="equation">HLEPNI.sub.X =HEPNI.sub.X *AHEPNI.sub.X-1 *AHEPNI.sub.X+1 *LEPNI.sub.X *ALEPNI.sub.X-1 *ALEPNI.sub.X+1

WHERE;

HLEPNI_X is the estimated expected probability of non-interference (EPNI) for allocated communication channel X;

HEPNI_X is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on allocated communication channel X;

AHEPNI_X-1 is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on the adjacent allocated communication channel below allocated communication channel X;

AHEPNI_X+1 is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on the adjacent allocated communication channel above allocated communication channel X;

LEPNI_X is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on allocated communication channel X;

ALEPNI_X-1 is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on the adjacent allocated communication channel below allocated communication channel X; and

ALEPNI_X+1 is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on the adjacent allocated communication channel above allocated communication channel X.

28. The method of claim 27 wherein the selecting step comprises selecting an available allocated communication channel with the highest estimated expected probability of non-interference.

29. The method of claim 27 wherein the selecting step further comprises selecting an available allocated communication channel which is not adjacent to an allocated communication channel which is then in use by the first cellular communication system.

30. The method of claim 27 wherein:

the set of allocated communication channels is divided into a plurality of groups, and

wherein the estimated expected probability of non-interference for an allocated communication channel in a group is determined in part based on the received signal strength indication data for all allocated communication channels in said group.

31. The method of claim 30 wherein the estimated expected probability of non-interference for an allocated communication channel in said group is adjusted by a group improvement factor or a group degradation factor.

32. The method of claim 27 further comprising the steps of:

sensing and measuring said received signal strength indication data over a period of time and storing said sensed and measured data in an RSSI database; and

determining said estimated expected probability of non-interference for each allocated communication channel based upon at least a portion of said stored data.

33. The method of claim 27 further comprising the steps of:

suspending said periodic sensing and measuring step during periods of low activity in said second cellular communication system.

34. The method of claim 27 further comprising the steps of:

determining the occurrence of channel assignment changes in said second cellular communication system;

in response to said determination, suspending said selecting step, deleting said stored received signal strength indication data for all allocated communication channels, and, thereafter, reactivating said sensing, storing, determining and selecting steps.

35. The method of claim 27 and wherein said allocated communication channels include a plurality of allocated control channels and comprising the step of:

periodically determining from said stored sensed and measured data the estimated expected probability of non-interference for each available allocated control channel.

36. The method of claim 35 wherein said plurality of allocated control channels include one allocated control channel in use by said first cellular communication system and at least one available allocated control channel;

and

during its period of use, suspending the periodic sensing and measuring step for said one allocated control channel.

37. The method of claim 36 further comprising the step of periodically replacing in said first cellular communication system said one allocated control channel with an available allocated control channel based on the estimated expected probability of non-interference of the available allocated control channels.

38. The method of claim 27 wherein the estimated expected probability on non-interference for an allocated communication channel is based on the received signal strength indication data for the allocated communication channel, the received signal strength indication data for the allocated communication channel adjacent to and above the allocated communication channel and on the received signal strength indication data for the allocated communication channel adjacent to and below the allocated communication channel.

39. The method of claim 27 wherein said first cellular communication system comprises a cellular auxiliary personal communication system and said second cellular communication system comprises a convention cellular communication system.

40. In a first cellular communication system having a set of allocated communication channels for transmitting and receiving communication signals in a geographic area and in which a second cellular communication system has a set of assigned channels for transmitting and receiving in the same geographic area, some of said assigned channels being the same as said allocated communication channels, the allocated communication channels including allocated voice channels and allocated control channels, a method of selecting an available allocated communication channel for use in transmitting and receiving communication signals in said first cellular communication system, comprising the steps of:

in said first cellular communication system, periodically collecting received signal strength indication measurements on each then available allocated communication channel;

periodically determining the estimated expected probability of non-interference for each allocated communication channel based on said received signal strength indication measurements;

selecting for use by said first cellular communication system an available allocated communication channel having the highest estimated expected probability of non-interference;

wherein the estimated expected probability of non-interference for each allocated communication channel is determined according to the following formula;

space="preserve" listing-type="equation">HLEPNI.sub.X =HEPNI.sub.X *AHEPNI.sub.X-1 *AHEPNI.sub.X+1 *LEPNI.sub.X *ALEPNI.sub.X-1 *ALEPNI.sub.X+1

WHERE;

HLEPNI_X is the estimated expected probability of non-interference (EPNI) for allocated communication channel X;

HEPNI_X is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on allocated communication channel X;

AHEPNI_X-1 is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on the adjacent allocated communication channel below allocated communication channel X;

AHEPNI_X+1 is the EPNI for allocated communication channel X as indicated by first frequency split measurements taken on the adjacent allocated communication channel above allocated communication channel X;

LEPNI_X is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on allocated communication channel X;

ALEPNI_X-1 is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on the adjacent allocated communication channel below allocated communication channel X; and

ALEPNI_X+1 is the EPNI for allocated communication channel X as indicated by second frequency split measurements taken on the adjacent allocated communication channel above allocated communication channel X.

41. The method of claim 40 wherein the selecting step further comprises selecting an available allocated communication channel with the highest estimated expected probability of non-interference and which is not adjacent to an allocated communication channel then in use by the first cellular communication system.

42. The method of claim 40 wherein the set of the allocated communication channels is divided into a plurality of groups, and wherein:

the estimated expected probability of non-interference for an allocated communication channel in a group is based in part on the received signal strength indication measurements for all allocated communication channels in said group.

43. The method of claim 42 wherein the estimated expected probability of non-interference for an allocated communication channel in said group is adjusted by a group improvement factor or a group degradation factor.

44. The method of claim 40 wherein said periodically collected received signal strength indication measurements are collected over an extended period of time and stored in an RSSI database, and wherein said estimated expected probability of non-interference for each allocated communication channel is based upon at least a portion of said collected and stored data.

45. The method of claim 40 wherein said allocated voice channels comprise forward voice channels each operating on a first frequency split and reverse voice channels each operating on a second frequency split and wherein the step of periodically collecting further comprises:

collecting received signal strength indication measurements for each said reverse voice channel on each corresponding first frequency split; and

collecting received signal strength indication measurements for each said forward voice channel on each corresponding second frequency split;

wherein said estimated expected probability of non-interference for each allocated voice channel is based on said received signal strength indication measurements collected on said corresponding first and second frequency splits.

46. The method of claim 45 wherein said collected received signal strength indication measurements taken on each first frequency split are recorded over an extended period of time into a first split RSSI database and said collected received signal strength indication measurements taken on each second frequency split are recorded over an extended period of time into a second frequency split RSSI database;

and

said estimated expected probability of non-interference for each allocated voice channel is based upon at least a portion of said recorded first frequency split received signal strength indication measurements and at least a portion of said recorded second frequency split received signal strength indication measurements.

47. The method of claim 45 wherein said set of allocated voice channels are divided into a plurality of groups;

and

wherein the estimated expected probability of non-interference for an allocated voice channel in a group is based upon at least a portion of said recorded first frequency split received signal strength indication measurements and at least a portion of said recorded second frequency split received signal strength indication measurements for all allocated voice channels in said group.

48. The method of claim 40 further comprising the steps of:

suspending said periodic collecting step during periods of low activity in said second cellular communication system.

49. The method of claim 44 further comprising the steps of:

determining channel assignment changes in said second cellular communication system;

in response to said determination, suspending said selecting step and

deleting said recorded received signal strength indication measurements for all allocated communications channels from said RSSI database and then reactivating said collecting, determining and selecting steps.

50. The method of claim 40 wherein said allocated control channels include one allocated control channel in use by said first cellular communication system and at least one available allocated control channel.

51. The method of claim 50 wherein said selecting step further comprises periodically replacing said one allocated control channel with an available allocated control channel based on the estimated expected probability of non-interference of the available allocated control channels.

52. The method of claim 40 wherein the estimated expected probability of non-interference for an allocated communication channel is based on the received signal strength indication measurements for the allocated communication channel, on the received signal strength indication measurements for an allocated communication channel adjacent to an above the allocated communication channel and on the received signal strength indication measurements for an allocated communication channel adjacent to and below the allocated communication channel.

53. The method of claim 40 wherein said first cellular communication system comprises a cellular auxiliary personal communication system and said second cellular communication system comprises a conventional cellular communication system.