System and method for frequency and time domain downlink inter-cell interference coordination

• US 9,826,545 B2
• Filed: 11/25/2015
• Issued: 11/21/2017
• Est. Priority Date: 10/20/2015
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Madan, Ritesh K., Chandrasekhar, Vikram, Nabar, Rohit Umesh, Shirali, Kedar Durgadas, Zhao, Qing
• Primary Examiner(s): Cheng, Peter
• Application Number:
  US14/951,987
• Publication Number:
  US 20170111919A1
• Time in Patent Office: 727 Days
• Field of Search: 370336
• 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 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 72/1273 of downlink data flows
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

An example method is provided in one example embodiment and includes receiving performance metric information from a plurality of small cell radios, wherein the performance metric information includes, at least in part, a number of user equipment that are to be scheduled on a first type and a second type of subframes for each small cell radio; determining resource allocation parameters for the plurality of small cell radios; exchanging interference information between two or more small cell radios of the plurality of small cell radios that includes an indication of whether a particular small cell radio is interfering with or is interfered by another small cell radio of the two or more small cell radios; and scheduling downlink resource transmissions on the first type and the second type of subframes for user equipment served by the two or more small cell radios.

Claims

1. A method comprising:

setting a performance metric threshold associated with performance of user equipments (UEs) served by a plurality of small cell radios;

determining, by each of the plurality of small cell radios, one or more restriction sets, wherein each restriction set identifies one or more UE that are not to be scheduled on a particular set of resources associated with a particular restriction set;

calculating a number of UEs that are to be scheduled across a first type of subframes and a second type of subframes based on a number of UEs belonging to each of the one or more restriction sets, wherein the first type of subframes and the second type of subframes are one of;

an almost blank subframe (ABS) type of subframes; and

a non-almost blank subframe (non-ABS) type of subframes;

receiving resource allocation parameters that are based on the restriction sets, wherein the resource allocation parameters include at least one of;

a value for a fraction of resources that can be scheduled in the first type of subframes for a fractional frequency reuse (FFR) portion of one or more subframes associated with the first type of subframes;

a value for a fraction of resources that can be scheduled in the second type of subframes for a fractional frequency reuse (FFR) portion of one or more subframes associated with the second type of subframes; and

a value for a fraction of resources that can be scheduled in both the first type of subframes and the second type of subframes for a fractional frequency reuse (FFR) portion of one or more subframes associated with both the first type of subframes and the second type of subframes;

exchanging interference information between two or more small cell radios of the plurality of small cell radios, wherein the interference information includes, at least in part, an indication of whether a particular small cell radio is interfering with another small cell radio of the two or more small cell radios and an indication of the particular small cell radio that it is interfered by another small cell radio of the two or more small cell radios; and

scheduling downlink resource transmissions on the first type of subframes and the second type of subframes for user equipment served by the two or more small cell radios based, at least in part on, the resource allocation parameters and the interference information exchanged between the two or more small cell radios.

2. The method of claim 1, wherein the performance metric threshold is associated with one of:

a signal-to-interference-plus-noise (SINR) threshold; and

an average spectral efficiency threshold.

3. The method of claim 1, wherein the performance metric threshold is associated with one of:

a quality of service (QoS) threshold;

a throughput rate threshold; and

a packet delay threshold.

4. The method of claim 1, wherein, for a particular small cell radio, the determining further comprises:

comparing a predicted performance for a particular UE served by the particular small cell radio for each of one or more resource sets; and

adding the particular UE to a restriction set for a particular resource set if the predicted performance for the particular UE is less than the performance metric threshold.

5. The method of claim 1, further comprising:

calculating an expected utility of UE performance for each of a plurality of candidate performance metric thresholds;

searching the calculated expected utilities to determine a maximum expected utility and particular candidate performance metric threshold associated with the maximum expected utility; and

setting the performance metric threshold equal to the particular candidate performance metric threshold.

6. The method of claim 1, further comprising, for a particular small cell radio:

measuring quality of service (QoS) for each UE of a plurality of first UEs served by the particular small cell radio that belong to a particular restriction set;

measuring quality of service (QoS) for each UE of a plurality of second UEs served by the particular small cell radio that do not belong to the particular restriction set;

comparing quality of service (QoS) performance for each UE of the plurality of first UEs to the performance metric threshold to determine whether the QoS performance for each UE of the plurality of first UEs is greater than the performance metric threshold, wherein the performance metric threshold is associated with a QoS performance metric threshold; and

based on a determination that the QoS performance for any UE of the plurality of first UEs is not greater than the performance metric threshold, reducing the performance metric threshold.

7. The method of claim 6, further comprising, for the particular small cell radio:

based on a determination that the QoS performance for any UE of the plurality of first UEs is greater than the performance metric threshold, comparing the QoS performance for each UE of the plurality of second UEs to the performance metric threshold to determine whether the QoS performance for each UE of the plurality of second UEs is greater than the performance metric threshold; and

based on a determination that the QoS performance for any UE of the plurality of second UEs is not greater than the performance metric threshold, increasing the performance metric threshold.

8. One or more non-transitory tangible media encoding logic that includes instructions for execution by a processor, wherein the execution causes the processor to perform operations, comprising:

setting a performance metric threshold associated with performance of user equipments (UEs) served by a plurality of small cell radios;

determining, by each of the plurality of small cell radios, one or more restriction sets, wherein each restriction set identifies one or more UE that are not to be scheduled on a particular set of resources associated for a particular restriction set;

calculating a number of UEs that are to be scheduled across a first type of subframes and a second type of subframes based on a number of UEs belonging to each of the one or more restriction sets, wherein the first type of subframes and the second type of subframes are one of;

an almost blank subframe (ABS) type of subframes; and

a non-almost blank subframe (non-ABS) type of subframes;

receiving resource allocation parameters that are based on the restriction sets, wherein the resource allocation parameters include at least one of;

a value for a fraction of resources that can be scheduled in the first type of subframes for a fractional frequency reuse (FFR) portion of one or more subframes associated with the first type of subframes;

a value for a fraction of resources that can be scheduled in the second type of subframes for a fractional frequency reuse (FFR) portion of one or more subframes associated with the second type of subframes; and

a value for a fraction of resources that can be scheduled in both the first type of subframes and the second type of subframes for a fractional frequency reuse (FFR) portion of one or more subframes associated with both the first type of subframes and the second type of subframes;

exchanging interference information between two or more small cell radios of the plurality of small cell radios, wherein the interference information includes, at least in part, an indication of whether a particular small cell radio is interfering with another small cell radio of the two or more small cell radios and an indication of the particular small cell radio that it is interfered by another small cell radio of the two or more small cell radios; and

scheduling downlink resource transmissions on the first type of subframes and the second type of subframes for user equipment served by the two or more small cell radios based, at least in part on, the resource allocation parameters and the interference information exchanged between the two or more small cell radios.

9. The media of claim 8, wherein the performance metric threshold is associated with one of:

a signal-to-interference-plus-noise (SINR) threshold; and

an average spectral efficiency threshold.

10. The media of claim 8, wherein the performance metric threshold is associated with one of:

a quality of service (QoS) threshold;

a throughput rate threshold; and

a packet delay threshold.

11. The media of claim 8, wherein, for a particular small cell radio, the determining further comprises:

comparing a predicted performance for a particular UE served by the particular small cell radio for each of one or more resource sets; and

adding the particular UE to a restriction set for a particular resource set if the predicted performance for the particular UE is less than the performance metric threshold.

12. The media of claim 8, the operations further comprising:

calculating an expected utility of UE performance for each of a plurality of candidate performance metric thresholds;

searching the calculated expected utilities to determine a maximum expected utility and particular candidate performance metric threshold associated with the maximum expected utility; and

setting the performance metric threshold equal to the particular candidate performance metric threshold.

13. The media of claim 8, the operations further comprising, for a particular small cell radio:

measuring quality of service (QoS) for each UE of a plurality of first UEs served by the particular small cell radio that belong to a particular restriction set;

measuring quality of service (QoS) for each UE of a plurality of second UEs served by the particular small cell radio that do not belong to the particular restriction set;

comparing quality of service (QoS) performance for each UE of the plurality of first UEs to the performance metric threshold to determine whether the QoS performance for each of the plurality of first UEs is greater than the performance metric threshold, wherein the performance metric threshold is associated with a QoS performance metric threshold; and

based on a determination that the QoS performance for any UE of the plurality of first UEs is not greater than the performance metric threshold, reducing the performance metric threshold.

14. The media of claim 13, the operations further comprising, for the particular small cell radio:

based on a determination that the QoS performance for any UE of the plurality of first UEs is greater than the performance metric threshold, comparing the QoS performance for each UE of the plurality of second UEs to the performance metric threshold to determine whether the QoS performance for each UE of the plurality of second UEs is greater than the performance metric threshold; and

based on a determination that the QoS performance for any UE of the plurality of second UEs is not greater than the performance metric threshold, increasing the performance metric threshold.

15. A communication system, comprising:

a server comprising at least one first memory element for storing first data and at least one first processor that executes instructions associated with the first data;

a plurality of small cell radios, each small cell radio comprising at least one corresponding second memory element for storing corresponding second data and at least one corresponding second processor that executes instructions associated with the corresponding second data for each small cell radio;

the server being adapted when executed by the at least one first processor to;

set a performance metric threshold associated with performance of user equipments (UEs) served by a plurality of small cell radios;

each of the plurality of small cell radios being adapted when executed by the at least one corresponding second processor for each small cell radio to;

determine one or more restriction sets, wherein each restriction set identifies one or more UE that are not to be scheduled on a particular set of resources associated for a particular restriction set; and

calculate a number of UEs that are to be scheduled across a first type of subframes and a second type of subframes based on a number of UEs belonging to each of the one or more restriction sets, wherein the first type of subframes and the second type of subframes are one of;

an almost blank subframe (ABS) type of subframes; and

a non-almost blank subframe (non-ABS) type of subframes;

receiving resource allocation parameters that are based on the restriction sets, wherein the resource allocation parameters include at least one of;

a value for a fraction of resources that can be scheduled in the first type of subframes for a fractional frequency reuse (FFR) portion of one or more subframes associated with the first type of subframes;

a value for a fraction of resources that can be scheduled in the second type of subframes for a fractional frequency reuse (FFR) portion of one or more subframes associated with the second type of subframes; and

a value for a fraction of resources that can be scheduled in both the first type of subframes and the second type of subframes for a fractional frequency reuse (FFR) portion of one or more subframes associated with both the first type of subframes and the second type of subframes;

exchange interference information between two or more small cell radios of the plurality of small cell radios, wherein the interference information includes, at least in part, an indication of whether a particular small cell radio is interfering with another small cell radio of the two or more small cell radios and an indication of the particular small cell radio that it is interfered by another small cell radio of the two or more small cell radios; and

schedule downlink resource transmissions on the first type of subframes and the second type of subframes for user equipment served by the two or more small cell radios based, at least in part on, the resource allocation parameters and the interference information exchanged between the two or more small cell radios.

16. The communication system of claim 15, wherein the performance metric threshold is associated with one of:

a signal-to-interference-plus-noise (SINR) threshold; and

an average spectral efficiency threshold.

17. The communication system of claim 15, wherein, for a particular small cell radio, the particular small cell radio is further adapted when executed by its at least one corresponding second processor to:

compare a predicted performance for a particular UE served by the particular small cell radio for each of one or more resource sets; and

add the particular UE to a restriction set for a particular resource set if the predicted performance for the particular UE is less than the performance metric threshold.

18. The communication system of claim 15, wherein the performance metric threshold is associated with one of:

a quality of service (QoS) threshold;

a throughput rate threshold; and

a packet delay threshold.

19. The communication system of claim 15, wherein, for a particular small cell radio, the particular small cell radio is further adapted when executed by its at least one corresponding second processor to:

measure quality of service (QoS) for each UE of a plurality of first UEs served by the particular small cell radio that belong to a particular restriction set;

measure quality of service (QoS) for each UE of a plurality of second UEs served by the particular small cell radio that do not belong to the particular restriction set;

compare quality of service (QoS) performance for each UE of the plurality of first UEs to the performance metric threshold to determine whether the QoS performance for each UE of the plurality of first UEs is greater than the performance metric threshold, wherein the performance metric threshold is associated with a QoS performance metric threshold; and

based on a determination that the QoS performance for any UE of the plurality of first UEs is not greater than the performance metric threshold, reduce the performance metric threshold.

20. The communication system of claim 19, wherein, for the particular small cell radio, the particular small cell radio is further adapted when executed by its at least one corresponding second processor to:

based on a determination that the QoS performance for any UE of the plurality of first UEs is greater than the performance metric threshold, compare the QoS performance for each UE of the plurality of second UEs to the performance metric threshold to determine whether the QoS performance for each UE of the plurality of second UEs is greater than the performance metric threshold; and

based on a determination that the QoS performance for any UE of the plurality of second UEs is not greater than the performance metric threshold, increase the performance metric threshold.