FRACTIONAL FREQUENCY REUSE IN HETEROGENEOUS NETWORKS

• US 20120157108A1
• Filed: 05/18/2011
• Published: 06/21/2012
• Est. Priority Date: 12/15/2010
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Dimou, Konstantinos, Falconetti, Laetitia, Huschke, Jörg, Boudreau, Gary David
• Granted Patent: US 8,559,961 B2
• Time in Patent Office: Days
• US Class Current: 455/450
• CPC Class Codes: H04J 11/005 of intercell interference
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA

Abstract

A base station node (BS) of a heterogeneous radio access network comprises a terminal locator (34) and a scheduler (36). The terminal locator (34) obtains an indication of location of a wireless terminal (30) in a cell served by the base station (BS), e.g., whether the wireless terminal (30) is in a center region (M) or an edge region (E) for the cell served by the base station node (BS). The scheduler (36) uses the indication of location to assign to the wireless terminal (30) a frequency of a frequency bandwidth usable by the heterogeneous radio access network. The scheduler (36) assigns a frequency from a partitioned portion of the frequency bandwidth if the cell served by the base station node is a micro cell and the wireless terminal is in an edge region of a micro cell. The scheduler (36) also assigns a frequency of the frequency bandwidth if the cell served by the base station node is a micro cell and the wireless terminal is in a center portion of the micro cell.

Claims

1. A method of operating a heterogeneous radio access network, the heterogeneous radio access network comprising a macro layer including at least one macro cell served by a macro base station node and a micro layer comprising at least one micro cell served by a micro base station node, the method comprising:

dividing a frequency bandwidth usable by the heterogeneous radio access network into a frequency-partitioned portion which is less than the entire frequency bandwidth;

assigning a frequency of the frequency-partitioned portion to a wireless terminal in an edge region of the micro cell;

assigning a frequency of the frequency bandwidth to a wireless terminal which is in a center region of the micro cell or at least within a center region of the macro cell.

2. The method of claim 1, wherein the act of assigning a frequency of the frequency bandwidth to a wireless terminal which is in a center region of the micro cell or at least within a center region of the macro cell is without regard to the partitioned portion.

3. The method of claim 1, further comprising assigning, without regard to the partitioned portion, a frequency of the frequency bandwidth to a wireless terminal that is within a center region of the macro cell.

4. The method of claim 1, further comprising determining whether the wireless terminal is in the center region or the edge region of the micro cell.

5. The method of claim 1, wherein the frequency-partitioned portion comprises plural partitions, and wherein the method further comprises assigning frequencies from the plural partitions to wireless terminals in an edge region of the macro cell and wireless terminals in an edge region of the micro cell.

6. The method of claim 1, further comprising:

dividing the frequency bandwidth usable by the heterogeneous radio access network into plural partitions;

assigning a frequency from a first partition to wireless terminals in an edge region of the macro cell;

assigning a frequency from a second partition to wireless terminals in a edge region of the micro cell.

7. The method of claim 1, wherein the heterogeneous radio access network comprises plural macro cells and plural micro cells, and wherein the method further comprises:

dividing the frequency bandwidth usable by the heterogeneous radio access network into plural partitions;

assigning a frequency from a first partition to wireless terminals in the edge region of a first macro cell;

assigning a frequency from a second partition to a wireless terminal in the edge region of a second macro cell;

assigning a frequency from a third partition to a wireless terminal in the edge region of a micro cell.

8. The method of claim 7, further comprising assigning the frequency from the third partition to the wireless terminal in the edge region of a micro cell regardless of whether the micro cell is in the first macro cell or the second macro cell.

9. The method of claim 1, wherein the heterogeneous radio access network comprises plural macro cells and wherein the plural macro cells each comprise plural micro cells, and wherein the method further comprises:

dividing the frequency bandwidth usable by the heterogeneous radio access network into plural partitions;

assigning a frequency from a first partition to a wireless terminal in an edge region of a first macro cell;

assigning a frequency from a second partition to a wireless terminal in an edge region of a second macro cell;

assigning a frequency from a third partition to a wireless terminal in an edge region of a first micro cell within the first macro cell;

assigning a frequency from a fourth partition to a wireless terminal in an edge region of a second micro cell within the first macro cell.

10. The method of claim 9, further comprising:

assigning a frequency from the third partition to a wireless terminal in an edge region of a first micro cell within the second macro cell;

assigning a frequency from the fourth partition to a wireless terminal in an edge region of a second micro cell within the second macro cell.

11. The method of claim 1, wherein the heterogeneous radio access network comprises plural macro cells and plural micro cells within each of the plural macro cells, further comprising:

dividing the frequency bandwidth usable by the heterogeneous radio access network into plural partitions;

assigning a frequency of a first partition to wireless terminals in an edge region of the plural micro cells within a first macro cell; and

,

assigning a frequency of a second partition to wireless terminals in an edge region of the plural micro cells within a second macro cell.

12. The method of claim 11, further comprising assigning, without regard to the plural partitions, a frequency of the frequency bandwidth to a wireless terminal which is in any of the plural macro cells or in the center region of any of the plural micro cells.

13. The method of claim 1, wherein the heterogeneous radio access network comprises plural macro cells and plural micro cells within each of the plural macro cells, further comprising:

dividing the frequency bandwidth usable by the heterogeneous radio access network into plural partitions;

assigning a frequency of a first partition to a wireless terminal in an edge region of a first micro cell within a first macro cell;

assigning a frequency of a second partition to a wireless terminal in an edge region of a second micro cell within the first macro cell.

14. The method of claim 13, further comprising:

assigning a frequency of the first partition to a wireless terminal in an edge region of a first micro cell within a second macro cell;

assigning a frequency of the second partition to a wireless terminal in an edge region of a second micro cell within the second macro cell.

15. The method of claim 1, wherein the heterogeneous radio access network comprises plural macro cells and plural micro cells within each of the plural macro cells, and wherein the method further comprises:

dividing the frequency bandwidth usable by the heterogeneous radio access network into plural partitions including a first partition and a second partition;

dividing the plural partitions into plural sub-partitions;

assigning a frequency of a second partition to a wireless terminal in an edge region of one of the plural micro cells by;

assigning a frequency of a first sub-partition of the second partition if the wireless terminal is in an edge region of a micro cell in the first macro cell; and

assigning a frequency of a second sub-partition of the second partition if the wireless terminal is in an edge region of a micro cell in the second macro cell.

16. The method of claim 15, further comprising assigning a frequency of a first partition to a wireless terminal in an edge region of one of the plural macro cells by:

assigning a frequency of a first sub-partition of the first partition if the wireless terminal is in an edge region of a first macro cell;

assigning a frequency of a second sub-partition of the first partition if the wireless terminal is in an edge region of a second macro cell.

17. The method of claim 15, further comprising assigning a frequency of a first partition to a wireless terminal in one of the plural macro cells by:

assigning a frequency of a first sub-partition of the first partition if the wireless terminal is in a first macro cell and interferes with any micro base station node;

assigning a frequency of a second sub-partition of the first partition if the wireless terminal is in a second macro cell and interferes with any micro base station node.

18. The method of claim 15, further comprising assigning a frequency of the second partition to a wireless terminal in one of the plural macro cells if the wireless terminal is in a macro cell and does not substantially interfere with any micro base station node.

19. The method of claim 18, further comprising assigning a frequency of to the wireless terminal in one of the plural macro cells by:

assigning a frequency of a first sub-partition of the second partition if the wireless terminal is in a first macro cell and does not substantially interfere with any micro base station node;

assigning a frequency of a second sub-partition of the second partition if the wireless terminal is in a second macro cell and does not substantially interfere with any micro base station node.

20. The method of claim 15, wherein in the frequency bandwidth the first sub-partition of the first partition is separated from the first sub-partition of the second partition by at least the second sub-partition of the first partition.

21. A base station node of a heterogeneous radio access network, the heterogeneous radio access network comprising a macro layer including at least one macro cell served by a macro base station node and a micro layer including at least one micro cell served by a micro base station node, the base station node comprising:

a terminal locator configured to obtain an indication of location of a wireless terminal in a cell served by the base station node;

a scheduler configured to use the indication of location to assign to the wireless terminal a frequency of the frequency bandwidth usable by the heterogeneous radio access network, the scheduler being configured to assign a frequency from a frequency-partitioned portion of the frequency bandwidth if the wireless terminal is in an edge region of the cell served by the base station node, the frequency-partitioned portion being less than the entire frequency bandwidth.

22. The base station node of claim 21, further comprising electronic circuitry operable to serve as the scheduler.

23. The base station node of claim 21, wherein the scheduler is configured to assign a frequency of the frequency bandwidth without regard to the frequency-partitioned portion if the wireless terminal is in a center portion of the cell served by the base station node.

24. The base station node of claim 21, wherein the cell is micro cell and the base station node is a micro base station node, wherein the heterogeneous radio access network comprises plural macro cells and plural micro cells within each of the plural macro cells, and wherein the frequency bandwidth used by the heterogeneous radio access network is divided into plural partitions.

25. The base station node of claim 24, wherein the scheduler is configured to assign a frequency from the second partition if the wireless terminal is in an edge region of a micro cell served by the micro base station node.

26. The base station node of claim 24, wherein the selected one of the plural partitions is a different partition than that which is used by a micro base station node within the macro cell to assign a frequency to any wireless terminal within the micro base station node.

27. The base station node of claim 25, wherein the selected one of the plural partitions is a same partition that is used by a micro base station node within another macro cell to assign a frequency to a wireless terminal in an edge region of the micro base station node which is in the another macro cell.

28. The base station node of claim 24, wherein the scheduler is further configured to assign the frequency from a selected one of plural partitions of the frequency bandwidth, the selected one of the plural partitions being a same partition which is used, by another base station node serving another micro cell in a same macro cell, to assign a frequency to another wireless terminal in an edge region of the another micro cell, but the selected one of the plural partitions being different from another partition which is used, by yet another base station node serving another micro cell in another macro cell which is adjacent to the macro cell, to assign a frequency to yet another wireless terminal in an edge region of the yet another micro cell.

29. The base station node of claim 24, wherein the scheduler is further configured to assign the frequency from a selected one of plural partitions of the frequency bandwidth, the selected one of the plural partitions being a different partition than that which is used, by another base station node serving another micro cell in a same macro cell, to assign a frequency to another wireless terminal in an edge region of the another micro cell.

30. The base station node of claim 24, wherein the plural partitions are divided into plural sub-partitions, wherein a first partition is associated with the plural macro cells and a second partition is associated with the plural micro cells, wherein a first sub-partition of the second partition is primarily for micro cells in a first macro cell and a second sub-partition of the second partition is primarily for micro cells in a second macro cell, wherein the base station node serves a particular micro cell comprising the plural micro cells, and wherein the scheduler is further configured to assign to the wireless terminal a frequency selected from a selected sub-partition of the second partition if the wireless terminal is in an edge region of the particular micro cell.

31. The base station node of claim 30, wherein the selected sub-partition of the second partition is associated with the macro cell in which the particular micro cell is located.

32. The base station node of claim 21, wherein the cell is a macro cell and the base station node is a macro base station node, wherein the heterogeneous radio access network comprises plural macro cells and plural micro cells within each of the plural macro cells, and wherein the frequency bandwidth used by the heterogeneous radio access network is divided into plural partitions.

33. The base station node of claim 32, wherein the scheduler is configured to assign a frequency of the frequency bandwidth without regard to the frequency-partitioned portion if the wireless terminal is in a center portion of the cell served by the base station node or does not substantially interfere with a micro cell.

34. The base station node of claim 32, the scheduler is configured to assign a frequency from a first partition if the wireless terminal is in an edge region of a macro cell served by the macro base station node.

35. The base station node of claim 32, the scheduler is further configured to assign a frequency from a selected one of plural partitions of the frequency bandwidth if the wireless terminal is in an edge region of the cell served by the macro base station node, the selected one of the plural partitions being a different partition than that which is used by another base station node serving an adjacent macro cell to assign a frequency to another wireless terminal in an edge region of the adjacent macro cell.

36. The base station node of claim 35, wherein the selected one of the plural partitions is a different partition than that which is used by a micro base station node within the macro cell to assign a frequency to any wireless terminal within the micro base station node.

37. The base station node of claim 35, wherein the selected one of the plural partitions is a same partition that is used by a micro base station node within another macro cell to assign a frequency to a wireless terminal in an edge region of the micro base station node which is in the another macro cell.

38. The base station node of claim 21, wherein the plural partitions are divided into plural sub-partitions, wherein a first partition is associated with the plural macro cells and a second partition is primarily associated with the plural micro cells, wherein the base station node serves a particular macro cell comprising the plural macro cells, and wherein the scheduler is further configured to assign to the wireless terminal a frequency of a selected one of the sub-partitions of the first partition if the wireless terminal is in an edge region of the particular macro cell or substantially interferes with a cell other than the particular macro cell.

39. The base station node of claim 38, wherein the selected one of the sub-partitions of the first partition is a sub-partition associated with the particular macro cell.

40. The base station node of claim 32, wherein the heterogeneous radio access network comprises plural macro cells and plural micro cells within each of the plural macro cells, wherein the frequency bandwidth usable by the heterogeneous radio access network is divided into plural partitions and the plural partitions are divided into plural sub-partitions, wherein a first partition is associated with the plural macro cells and a second partition is primarily associated with the plural micro cells, wherein the base station node serves a particular macro cell comprising the plural macro cells, and wherein the scheduler is further configured to assign to the wireless terminal a frequency of the frequency bandwidth usable by the heterogeneous radio access network without regard to partitioning if the wireless terminal does not substantially interfere with a cell other than the particular macro cell.

41. The base station node of claim 32, wherein the heterogeneous radio access network comprises plural macro cells and plural micro cells within each of the plural macro cells, wherein the frequency bandwidth usable by the heterogeneous radio access network is divided into plural partitions and the plural partitions are divided into plural sub-partitions, wherein a first partition is associated with the plural macro cells and a second partition is associated with the plural micro cells, wherein the base station node serves a particular macro cell comprising the plural macro cells, and wherein the scheduler is further configured to assign to the wireless terminal a frequency of the second partition if the wireless terminal substantially interferes with a macro cell other than the particular macro cell and does not substantially interfere with a micro cell.

42. The base station node of claim 41, wherein the scheduler is further configured to assign to the wireless terminal a frequency of a selected one of the sub-partitions of the second partition, and wherein the selected one of the sub-partitions of the second partition is associated with the particular macro cell.