Radio communications systems

• US 6,549,782 B2
• Filed: 03/31/1999
• Issued: 04/15/2003
• Est. Priority Date: 03/31/1999
• Status: Expired due to Term

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Siemens Information And Communication Networks, Inc.
• Inventors: Roy, Debasish Dev
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): West, Lewis G.
• Application Number:
  US09/282,480
• Publication Number:
  US 20020107024A1
• Time in Patent Office: 1,476 Days
• Field of Search: 455/450, 455/446, 455/447, 455/62, 455/226.2, 455/226.3, 455/561, 455/422, 455/575, 455/451, 455/509, 455/452, 455/453
• US Class Current: 455/450
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/04 Traffic adaptive resource partitioning
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning

Abstract

A system and method for efficiently assigning a plurality of channels among a plurality of nodes in a radio communications system. For each node in the system, a buffer zone is established. The members of a particular node'"'"'s buffer zone are that subset of the plurality of nodes in the system that are prohibited from using a channel simultaneously with the particular node. When a particular node is in need of a channel assignment, the system will assign a channel to the particular node from a subset of channels that excludes channels assigned to nodes within the particular channel'"'"'s buffer zone. A co-channel zone is for each particular node is also established which includes a subset of the plurality of nodes that is near the particular node, but excludes nodes outside the particular node'"'"'s buffer zone.

Claims

1. In a radio communications system having a plurality of nodes and a plurality of channels, a method for assigning one of the plurality of channels to a selected one of the plurality of nodes, such method comprising:

associating with each one of the plurality of nodes a subset of the plurality of nodes, such subset providing a “

buffer zone”

associated with such one of the plurality of nodes, such subset of the plurality of nodes being stored in a database;

determining, on a real-time basis for the selected one of the plurality of nodes, a subset of the plurality of channels, the subset of channels excluding channels assigned to the nodes in the “

buffer zone”

associated with such selected one of the nodes, such determining comprising accessing the database; and

assigning one of the channels from the subset of channels to the selected one of the nodes.

2. The method of claim 1 wherein the associating is performed at a time prior to any channel assignment.

3. The method of claim 2 wherein the associating is performed in non-real time.

4. The method of claim 1 wherein the assigning further comprises:

sorting the subset of channels according to a predetermined cost function, and

selecting from the sorted subset of channels a one channel for the assigning that minimizes the cost function.

5. The method of claim 4 wherein the assigning assigns a one of the subset of channels that minimizes system-wide probability of blocking.

6. The method of claim 4 wherein the assigning assigns a one of the subset of channels that maximizes system-wide channel availability.

7. The method of claim 1 further comprising:

determining a co-channel zone surrounding the selected one node, said co-channel zone comprising a subset of nodes that are within a predetermined distance of the selected one node and that are not within the selected one node'"'"'s buffer zone; and

wherein the assigning assigns a one of the subset of channels as a function of channel usage in the co-channel zone.

8. The method of claim 7 wherein the assigning minimizes co-channel interference within the co-channel zone.

9. The method of claim 7 wherein the assigning maximizes channel reuse within the co-channel zone.

10. In a radio communications system having a plurality of nodes and a plurality of channels, a method for assigning one of the plurality of channels to a selected one of the plurality of nodes, such method comprising:

associating with each one of the plurality of nodes a subset of the plurality of nodes, such subset providing a “

buffer zone”

associated with such one of the plurality of nodes;

determining, on a real-time basis for the selected one of the plurality of nodes, a subset of the plurality of channels, the subset of channels excluding channels assigned to the nodes in the “

buffer zone”

associated with such selected one of the nodes; and

assigning one of the channels from the subset of channels to the selected one of the nodes;

wherein the associating is performed at a time prior to any channel assignment;

wherein the associating is performed in non-real time;

wherein the assigning further comprises;

sorting the subset of channels according to a predetermined cost function, and

selecting from the sorted subset of channels a one channel for the assigning that minimizes the cost function;

wherein the assigning assigns a one of the subset of channels that is used least in the system.

11. In a cellular or PCS radio telecommunications system having of a plurality of cells and a plurality of channels assignable among the plurality of cells, a method of assigning the channels, such method comprising:

(a) prior to entering an operating mode,

(i) determining a channel-reuse interference criteria for the system,

(ii) determining for each one of the plurality of cells a subset of the plurality of cells failing to meet the channel-reuse interference criteria when paired with such one of the cells, such subset providing a buffer zone, such subset of the plurality of cells being stored in a database,

and

(b) during the operating mode,

(i) selecting one of the cells requiring a channel assignment,

(ii) determining a subset of channels of the plurality of channels on a real-time basis, such subset having members other than channels assigned to cells in the buffer zone for the selected one of the cells, such determining comprising accessing the database,

(iii) assigning one of the subset.of channels to the selected one of the cells.

12. The method of claim 11 further comprising:

(a) prior to entering the operating mode;

for each cell of the plurality of cells, determining a “

co-channel zone”

comprising cells that are within a predetermined distance from said each cell and that are outside said each cell'"'"'s buffer zone, and

(b) during the operating mode,

selecting a one of the subset of channels for assignment as a function of channel usage within the co-channel zone.

13. The method of claim 11 wherein the channel reuse interference criteria is selected as a function of the worst-case reuse distance in the system.

14. The method of claim 11 wherein the radio communications system is digital.

15. The method of claim 11 wherein the radio communications system is analog.

16. In a radio communications system having a plurality of nodes and a plurality of channels and having a portion of the plurality of channels assigned to a portion of the plurality of nodes, a method for assigning one of the plurality of channels to a selected one of the plurality of nodes, such method comprising:

associating for each node of the plurality of nodes a subset of the plurality of nodes forming a “

buffer zone”

for said each node, such subset of the plurality of nodes being stored in a database,

selecting a channel from the plurality of channels,

checking the database to determine if the selected channel is assigned to at least one of the plurality of nodes within the selected one node'"'"'s “

buffer zone”

,

repeating the selecting and checking if the selected channel is assigned to at least one of the plurality of nodes within the selected one node'"'"'s “

buffer zone”

,

assigning on a real-time basis the selected channel to the selected one node if the selected channel is unassigned to every node of the selected one node'"'"'s “

buffer zone”

.

17. The method of claim 16 wherein the associating step is performed prior to any channel assignment.

18. A radio communications system comprising:

a plurality of nodes, each of the plurality of nodes comprising a radio transceiver for communicating with stations over a plurality of channels, the plurality of channels being assignable among the plurality of nodes,

a controller for assigning the plurality of channels among the-plurality of nodes, the controller, the controller comprising;

a memory having stored therein;

data correlating for each node of the plurality of nodes a subset of nodes of the plurality of nodes;

data correlating the plurality of channels to the plurality of nodes to which the plurality of channels may be assigned;

a controller for associating a subset of the plurality of channels with a particular selected node, the subset excluding channels assigned to one or more nodes within the stored subset of nodes correlated to the particular selected node, and for assigning on a real-time basis one of the associated subset of channels to the particular selected node, and

wherein the memory has stored therein the associated subset of channels.

19. The mobile radio communications system of claim 18 wherein the controller is disposed centralized in a single location.

20. The mobile radio communications system of claim 18 wherein the controller is distributed among multiple locations.

21. The mobile radio communications system of claim 18 wherein the controller assigns the one channel of the determined subset of channels so as to minimize a predetermined cost function.

22. A radio communications system comprising:

a plurality of nodes, each of the plurality of nodes comprising a radio transceiver for communicating with mobile stations over a plurality of channels, the plurality of channels being assignable among the plurality of nodes,

a controller for assigning the plurality of channels among the plurality of nodes, the controller, the controller comprising;

a first memory having stored therein data correlating for each node of the plurality of nodes a subset of nodes of the plurality of nodes,

a second memory having stored therein data correlating the plurality of channels to the plurality of nodes to which the plurality of channels may be assigned,

a controller for associating in real-time a subset of the plurality of channels with a particular selected node, the subset excluding channels assigned to one or more nodes within the stored subset of nodes correlated to the particular selected node, and for assigning one of the associated subset of channels to the particular selected node, and

a third memory having stored therein the associated subset of channels.

23. The mobile radio communications system of claim 22 wherein the controller is disposed centralized in a single location.

24. The mobile radio communications system of claim 22 wherein the controller is distributed among multiple locations.

25. The mobile radio communications system of claim 22 wherein the controller assigns the one channel of the determined subset of channels so as to minimize a predetermined cost function.

26. In a radio communications system having a plurality of nodes and a plurality of channels, a method for assigning one of the plurality of channels to a selected one of the plurality of nodes, such method comprising:

establishing a database associating each one of the plurality of nodes with a subset of the plurality of nodes, such subset providing a “

buffer zone”

associated with such one of the plurality of nodes;

accessing the established database to determine, on a real-time basis for the selected one of the plurality of nodes, a subset of the plurality of channels, the subset of channels excluding channels to the nodes in the “

buffer zone”

associated with such selected one of the nodes; and

assigning one of the channels from the subset of channels to the selected one of the nodes.

27. The method of claim 26 wherein the establishing of the database is performed at a time prior to any channel assignment.

28. The method of claim 27 wherein the accessing is performed in non-real time.

29. The method of claim 26 wherein the assigning further comprises:

sorting the subset of channels according to a predetermined cost function, and

selecting from the sorted subset of channels a one channel for the assigning that minimizes the cost function.

30. The method of claim 29 wherein the assigning assigns a one of the subset of channels that minimizes system-wide probability of blocking.

31. The method of claim 29 wherein the assigning assigns a one of the subset of channels that maximizes system-wide channel availability.

33. The method of claim 26 further comprising:

determining a co-channel zone surrounding the selected one node, said co-channel zone comprising a subset of nodes that are within a predetermined distance of the selected one node and that are not within the selected one node'"'"'s buffer zone; and

wherein the assigning assigns a one of the subset of channels as a function of channel usage in the co-channel zone.

34. The method of claim 33 wherein the assigning minimizes co-channel interference within the co-channel zone.

35. The method of claim 33 wherein the assigning maximizes channel reuse within the co-channel zone.

32. In a radio communications system having a plurality of nodes and a plurality of channels, a method for assigning one of the plurality of channels to a selected one of the plurality of nodes, such method comprising:

establishing a database associating each one of the plurality of nodes with a subset of the plurality of nodes, such subset providing a “

buffer zone”

associated with such one of the plurality of nodes;

accessing the database to determine, for the selected one of the plurality of nodes, a subset of the plurality of channels, the subset of channels excluding channels assigned to the nodes in the “

buffer zone”

associated with such selected one of the nodes; and

assigning one of the channels from the subset of channels to the selected one of the nodes;

wherein the accessing of the database is performed at a time prior to any channel assignment;

wherein the accessing the database is performed in non-real time;

wherein the assigning further comprises;

sorting the subset of channels according to a predetermined cost function, and

selecting from the sorted subset of channels a one channel for the assigning that minimizes the cost function;

wherein the assigning assigns a one of the subset of channels that is used least in the system.

36. In a cellular or PCS radio telecommunications system having of a plurality of cells and a plurality of channels assignable among the plurality of cells, a method of assigning the channels, such method comprising:

(a) prior to entering an operating mode,

(i) determining a channel-reuse interference criteria for the system,

(ii) establishing a database which establishes for each one of the plurality of cells a subset of the plurality of cells failing to meet the channel-reuse interference criteria when paired with such one of the cells, such subset providing a buffer zone,

and

(b) during the operating mode,

(i) selecting one of the cells requiring a channel assignment,

(ii) accessing the database to determine a subset of channels of the plurality of channels on a real-time basis, such subset having members other than channels assigned to cells in the buffer zone for the selected one of the cells,

(iii) assigning one of the subset of channels to the selected one of the cells.

37. The method of claim 36 further comprising:

(a) prior to entering the operating mode;

for each cell of the plurality of cells, determining a “

co-channel zone”

comprising cells that are within a predetermined distance from said each cell and that are outside said each cell'"'"'s buffer zone, and

(b) during the operating mode,

selecting a one of the subset of channels for assignment as a function of channel usage within the co-channel zone.

38. The method of claim 36 wherein the channel reuse interference criteria is selected as a function of the worst-case reuse distance in the system.

39. The method of claim 36 wherein the radio communications system is digital.

40. The method of claim 36 wherein the radio communications system is analog.

41. In a radio communications system having a plurality of nodes and a plurality of channels and having a portion of the plurality of channels assigned to a portion of the plurality of nodes, a method for assigning one of the plurality of channels to a selected one of the plurality of nodes, such method comprising:

establishing a database which associates for each node of the plurality of nodes a subset of the plurality of nodes forming a “

buffer zone”

for said each node,

selecting a channel from the plurality of channels,

checking the database to determine if the selected channel is assigned to at least one of the plurality of nodes within the selected one node'"'"'s “

buffer zone”

,

repeating the selecting and checking if the selected channel is assigned to at least one of the plurality of nodes within the selected one node'"'"'s “

buffer zone”

,

assigning on a real-time basis the selected channel to the selected one node if the selected channel is unassigned to every node of the selected one node'"'"'s “

buffer zone”

.

42. The method of claim 41 wherein the establishing of the database step is performed prior to any channel assignment.