Dynamic scheduling of non-interfering clusters in a distributed diversity communications system

• US 9,326,152 B1
• Filed: 11/04/2014
• Issued: 04/26/2016
• Est. Priority Date: 11/04/2014
• Status: Expired due to Fees

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Yiu, Simon, Calin, Doru
• Primary Examiner(s): Patel, Dhaval
• Application Number:
  US14/532,079
• Publication Number:
  US 20160127911A1
• Time in Patent Office: 539 Days
• Field of Search: 455/447, 370/329, 370/330, 370/280, 370/278, 370/338, 370/431
• US Class Current: 1/1
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems

Abstract

In certain embodiments, a cellular wireless communications network has clusters, each cluster having a plurality of cells and a cluster-level controller that dynamically divides the cluster into non-interfering sub-clusters for each resource allocation unit (e.g., physical resource block). Each sub-cluster has one or more cells that transmit to a single user in the cluster for the resource allocation unit, and at least one sub-cluster has at least two cells that transmit to a single user for the resource allocation unit using a distributed diversity mode of communication in which the at least two cells transmit the same data to the single user. The controller divides the cluster into sub-clusters based on determinations of whether users in the cluster are susceptible to interference from non-serving cells in the cluster. By assigning potentially interfering, non-serving cells to the sub-cluster for a user, those non-serving cells are eliminated as sources of interference.

Claims

1. A cellular wireless communications network comprising one or more clusters, each cluster comprising:

a plurality of cells; and

a cluster-level controller that dynamically divides the cluster into a set of non-interfering sub-clusters for a resource allocation unit, wherein;

each sub-cluster comprises one or more cells that transmit to a single user in the cluster for the resource allocation unit;

at least one sub-cluster comprises at least two cells that transmit to a corresponding single user in the cluster for the resource allocation unit;

the controller dynamically divides the cluster into the set of non-interfering sub-clusters based on a cluster-level ranking of users in the cluster;

each user in the cluster is connected to only one serving cell in the cluster; and

for a highest-rank user in the ranking, the controller defines a sub-cluster for the highest-rank user, wherein;

if the controller determines that the highest-rank user has one or more potentially interfering, non-server cells in the cluster, then the controller includes in the sub-cluster for the highest-rank user (i) the one or more potentially interfering, non-serving cells and (ii) the serving cell for the highest-rank user; and

if the controller determines that the highest-rank user has no potentially interfering, non-server cells in the cluster, then the controller includes in the sub-cluster for the highest-rank user only the serving cell for the highest-rank user.

2. The invention of claim 1, wherein the controller dynamically divides the cluster into the set of non-interfering sub-clusters for the resource allocation unit based on channel conditions in the cluster.

3. The invention of claim 1, where the resource allocation unit corresponds to at least one time symbol and at least one frequency subcarrier.

4. The invention of claim 1, wherein the controller determines that a non-serving cell in the cluster is a potentially interfering, non-serving cell for the highest-rank user when a measured power level at the highest-rank user from the non-serving cell is less than a specified threshold value below a measured power level at the highest-rank user from the serving cell for the highest-rank user.

5. The invention of claim 1, wherein, after defining the sub-cluster for the highest-rank user:

the controller updates a list of available cells in the cluster by removing the cells in the sub-cluster;

the controller updates the ranking of users by removing the highest-rank user and any other users connected to any of the cells in the sub-cluster; and

if both of (i) the updated list of available cells and (ii) the updated ranking of users are not empty, then the controller attempts to schedule transmission to a highest-rank user in the updated ranking.

6. The invention of claim 1, wherein, if the highest-rank user is susceptible to interference from a cell that has already been scheduled for the resource allocation unit, then the highest-rank user is removed from the ranking without scheduling any transmission to the highest-rank user for the resource allocation unit.

7. The invention of claim 1, wherein:

each cell ranks its own users and determines its cell-level highest-rank user;

one or more cells identify their cell-level highest-rank users to the controller; and

the controller generates the cluster-level ranking based on the identified cell-level highest-rank users.

8. The invention of claim 7, wherein:

each cell determines whether or not its cell-level highest-rank user is susceptible to interference from another cell in the cluster;

each cell that determines that its cell-level highest-rank user is not susceptible to interference schedules its cell-level highest-rank user for the resource allocation unit; and

each cell that determines that its cell-level highest-rank user is susceptible to interference identifies its cell-level highest-rank user to the controller for the resource allocation unit.

9. The invention of claim 1, wherein the at least two cells in the at least one sub-cluster transmit to the corresponding single user using (i) a distributed diversity mode of communication in which the at least two cells share a single transmission code or (ii) other coordinated multipoint (COMP) scheme.

10. The invention of claim 9, wherein:

the shared transmission code is a block code; and

each cell in the at least one sub-cluster is assigned a different subset of one or more columns of the block code.

11. The invention of claim 1, wherein:

the controller dynamically divides the cluster into a corresponding set of non-interfering sub-clusters independently for each of multiple, different resource allocation units; and

the corresponding sets of non-interfering sub-clusters are different for at least two of the resource allocation units.

12. The invention of claim 1, wherein:

one or more of the cells have a remote radio head (RRH), but no dedicated baseband unit (BBU); and

the cluster comprises a shared BBU for all of the cells in the cluster, wherein the shared BBU implements the controller.

13. The invention of claim 12, wherein the plurality of cells further comprises a master cell having the shared BBU.

14. The invention of claim 13, wherein:

none of the cells in the cluster has a BBU; and

the shared BBU is cloud-implemented.

15. The invention of claim 1, wherein the communications network is an LTE communications network.

16. The invention of claim 1, wherein the network further comprises one or more other clusters, wherein:

each other cluster has a plurality of other cells; and

each other cluster comprises an other cluster-level controller that dynamically divides the other cluster into an other set of non-interfering sub-clusters, each sub-cluster comprising one or more other cells that transmit to a single user in the other cluster.

17. A cluster-level controller for the network of claim 1.

18. A cell for the network of claim 1.

19. A cellular wireless communications network comprising one or more clusters, each cluster comprising:

a plurality of cells; and

a cluster-level controller that dynamically divides the cluster into a set of non-interfering sub-clusters for a resource allocation unit, wherein;

each sub-cluster comprises one or more cells that transmit to a single user in the cluster for the resource allocation unit;

at least one sub-cluster comprises at least two cells that transmit to a corresponding single user in the cluster for the resource allocation unit;

the controller dynamically divides the cluster into the set of non-interfering sub-clusters based on a cluster-level ranking of users in the cluster;

each cell ranks its own users and determines its cell-level highest-rank user;

one or more cells identify their cell-level highest-rank users to the controller; and

the controller generates the cluster-level ranking based on the identified cell-level highest-rank users.

20. The invention of claim 19, wherein:

each cell determines whether or not its cell-level highest-rank user is susceptible to interference from another cell in the cluster;

each cell that determines that its cell-level highest-rank user is not susceptible to interference schedules its cell-level highest-rank user for the resource allocation unit; and

each cell that determines that its cell-level highest-rank user is susceptible to interference identifies its cell-level highest-rank user to the controller for the resource allocation unit.

21. A cluster-level controller for the network of claim 19.

22. A cell for the network of claim 19.

23. A cellular wireless communications network comprising one or more clusters, each cluster comprising:

a plurality of cells; and

a cluster-level controller that dynamically divides the cluster into a set of non-interfering sub-clusters for a resource allocation unit, wherein;

each sub-cluster comprises one or more cells that transmit to a single user in the cluster for the resource allocation unit;

at least one sub-cluster comprises at least two cells that transmit to a corresponding single user in the cluster for the resource allocation unit;

the controller dynamically divides the cluster into a corresponding set of non-interfering sub-clusters independently for each of multiple, different resource allocation units; and

the corresponding sets of non-interfering sub-clusters are different for at least two of the resource allocation units.

24. A cluster-level controller for the network of claim 23.

25. A cellular wireless communications network comprising one or more clusters, each cluster comprising:

a plurality of cells; and

a cluster-level controller that dynamically divides the cluster into a set of non-interfering sub-clusters for a resource allocation unit, wherein;

each sub-cluster comprises one or more cells that transmit to a single user in the cluster for the resource allocation unit;

at least one sub-cluster comprises at least two cells that transmit to a corresponding single user in the cluster for the resource allocation unit;

one or more of the cells have a remote radio head (RRH), but no dedicated baseband unit (BBU); and

the cluster comprises a shared BBU for all of the cells in the cluster, wherein the shared BBU implements the controller.

26. The invention of claim 25, wherein the plurality of cells further comprises a master cell having the shared BBU.

27. The invention of claim 26, wherein:

none of the cells in the cluster has a BBU; and

the shared BBU is cloud-implemented.