APPARATUS AND METHOD FOR LOAD BALANCING

• US 20120236712A1
• Filed: 03/14/2011
• Published: 09/20/2012
• Est. Priority Date: 03/14/2011
• Status: Active Grant

• Current Assignee: Clearwire Ip Holdings LLC (Deutsche Telekom AG)
• Original Assignee: Clear Wireless LLC (Deutsche Telekom AG)
• Inventors: PARK, Sungki, SATAPATHY, Durga Prasad
• Granted Patent: US 8,605,586 B2
• Time in Patent Office: Days
• US Class Current: 370/230
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 36/22 for handling the traffic

Abstract

Systems and methods of balancing traffic load in a wireless communication network include calculating a load metric for each of a plurality of users, wherein each of the plurality of users, in operation, are in communication with a first base station using an overloaded carrier associated with the first base station. Such load metric for each user may include a plurality of metric factors related at least to an associated communication link. Based on the calculated load metric, a transfer-deserving user from the plurality of users may be determined. The transfer-deserving user may be associated with a highest value of an associated calculated load metric. For load balancing at the first base station, the associated communication link of the transfer-deserving user may be transferred from the overloaded carrier to a target carrier, wherein the target carrier may be associated with either the first base station or a second base station.

Claims

1. A method of balancing traffic load in a wireless communication network, the method comprising:

calculating, using a processor operatively associated with a first base station, a load metric for each of a plurality of users, wherein each of the plurality of users, in operation, are in communication with the first base station using an overloaded carrier associated with the first base station, and wherein the load metric for each of the plurality of users comprises a plurality of metric factors related at least to an associated communication link;

determining, using the processor, a transfer-deserving user from the plurality of users, the transfer-deserving user being associated with a highest value of an associated calculated load metric; and

transferring, using the processor, the associated communication link of the transfer-deserving user from the overloaded carrier to a target carrier, wherein the target carrier is associated with either the first base station or a second base station.

2. The method of claim 1, wherein, after the communication link of the transfer-deserving user is transferred, said calculating, said determining and said transferring are repeated for any remaining users in the plurality of users in communication with the first base station using the overloaded carrier.

3. The method of claim 1, wherein the metric factors comprise two or more parameters selected from the group consisting of:

a service flow type associated with the user, a number of service flows associated with the user, a number of time slots allocated to the user, a modulation and coding scheme assigned to the user, a number of times a user-associated communication link has already been transferred from one carrier to another carrier, a number of times a user-associated communication link has been exchanged between two specific carriers, a service flow type associated with one or more users of a neighbor carrier associated with the first base station or the second base station, and a number of service flows associated with one or more users of the neighbor carrier,

wherein each of the service flows of users associated with the overloaded carrier and the service flows of users associated with the neighbor carrier are represented by one of a plurality of Quality of Service (QoS) values.

4. The method of claim 1, wherein a traffic load of the target carrier is less than a target load threshold value.

5. The method of claim 1, wherein a signal strength (SS) of the target carrier is greater than a target SS threshold value.

6. The method of claim 1, further comprising:

determining, using the processor, whether a traffic load of the overloaded carrier is greater than a first threshold value,

wherein said calculating is only performed responsive to a determination that the traffic load of the overloaded carrier is greater than the first threshold value.

7. The method of claim 6, wherein said determining whether the traffic load of the overloaded carrier is greater than the first threshold value is performed periodically.

8. The method of claim 6, responsive to a determination that the traffic load of the overloaded carrier is less than the first threshold value and greater than a second threshold value, wherein the second threshold value is less than the first threshold value, the method further comprises:

equalizing a combined traffic load of a plurality of carriers associated with the first base station such that an individual traffic load of each of the plurality of the carriers is essentially equalized, wherein the plurality of carriers includes the overloaded carrier.

9. The method of claim 8, wherein at least one of the first threshold value or the second threshold value is a function of at least one of a plurality of threshold factors, the plurality of threshold factors comprising one or more parameters selected from the group consisting of:

a total number of users in communication with the first base station using the plurality of carriers associated therewith, a total number of utilized time slots associated with the first base station, a number of time slots allocated to each of the plurality of carriers, a service flow type associated with each of the plurality of carriers, a number of service flows associated with each of the plurality of carriers, and a modulation and coding scheme assigned to one or more users associated with each of the plurality of carriers.

10. The method of claim 1, wherein at least one of the first base station and the second base station comprises a 3G base station.

11. The method of claim 10, wherein the 3G base station comprises a CDMA/EvDO base station.

12. The method of claim 1, wherein at least one of the first base station and the second base station comprises a 4G base station.

13. The method of claim 12, wherein the 4G base station comprises a WiMAX base station.

14. The method of claim 12, wherein the 4G base station comprises an LTE base station.

15. The method of claim 1, wherein at least one of the first base station and the second base station is operational with the plurality of users using a multiple access scheme, the multiple access scheme comprising Orthogonal Frequency Division Multiple Access (OFDMA).

16. A method of balancing traffic load in a wireless communication network, the method comprising:

determining, using a processor operatively associated with a first base station, whether a new user has been associated with a plurality of existing users based on at least one of a plurality of triggering events, the triggering events comprising an initial network entry event, a re-entry event and a handover event, wherein the new user and each of the plurality of existing users, in operation, are in communication with the first base station using an overloaded carrier associated with the first base station; and

responsive to a determination that the new user has been associated with the plurality of existing users, adjusting a traffic load of the overloaded carrier based on a load metric for each of the plurality of existing users and the new user, the load metric comprising a plurality of metric factors related to a respective user.

17. The method of claim 16, wherein said adjusting includes transferring a communication link of at least one of the plurality of existing users or the new user from the overloaded carrier to a target carrier, wherein the target carrier is associated with either the first base station or a second base station.

18. The method of claim 17, wherein the metric factors comprise two or more parameters selected from the group consisting of:

a service flow type associated with the user, a number of service flows associated with the user, a number of time slots allocated to the user, a modulation and coding scheme assigned to the user, a number of times a user-associated communication link has already been transferred from one carrier to another carrier, a number of times a user-associated communication link has been exchanged between two specific carriers, a service flow type associated with one or more users of a neighbor carrier associated with the first base station or the second base station, and a number of service flows associated with one or more users of the neighbor carrier,

wherein each of the service flows of users associated with the overloaded carrier and the service flows of users associated with the neighbor carrier are represented by one of a plurality of Quality of Service (QoS) values.

19. An apparatus capable of operating and balancing traffic load in a wireless network, the apparatus comprising:

a transceiver configured to exchange data with each of a plurality of users via an associated communication link established using an overloaded carrier; and

a processor operatively coupled to the transceiver, wherein the processor is configured to;

calculate a load metric for each of the plurality of users comprising a plurality of metric factors related at least to the associated communication link;

determine a transfer-deserving user from the plurality of users, the transfer-deserving user being associated with a highest value of an associated calculated load metric; and

transfer the associated communication link of the transfer-deserving user from the overloaded carrier to a target carrier, wherein the target carrier is associated with either said apparatus or another wireless apparatus of the wireless network.

20. The apparatus of claim 19, wherein, after the processor transfers the communication link of the transfer-deserving user, the processor is further configured to repeat said operations to calculate, determine and transfer for any remaining users in the plurality of users in communication with the transceiver using the overloaded carrier.

21. The apparatus of claim 19, wherein the metric factors comprise two or more parameters selected from the group consisting of:

a service flow type associated with the user, a number of service flows associated with the user, a number of time slots allocated to the user, a modulation and coding scheme assigned to the user, a number of times a user-associated communication link has already been transferred from one carrier to another carrier, a number of times a user-associated communication link has been exchanged between two specific carriers, a service flow type associated with one or more users of a neighbor carrier associated with said apparatus or said other wireless apparatus, and a number of service flows associated with one or more users of the neighbor carrier,

wherein each of the service flows of users associated with the overloaded carrier and the service flows of users associated with the neighbor carrier are represented by one of a plurality of Quality of Service (QoS) values.

22. The apparatus of claim 19, wherein a traffic load of the target carrier is less than a target load threshold value.

23. The apparatus of claim 19, wherein a signal strength (SS) of the target carrier is greater than a target SS threshold value.

24. The apparatus of claim 19, wherein the processor is further configured to:

determine whether a traffic load of the overloaded carrier is greater than a first threshold value,

wherein the processor is configured to calculate the load metric for each of the plurality of users only responsive to a determination that the traffic load of the overloaded carrier is greater than the first threshold value.

25. The apparatus of claim 24, wherein the processor is configured to determine whether the traffic load of the overloaded carrier is greater than the first threshold value is performed on a periodic basis.

26. The apparatus of claim 24, wherein responsive to a determination that the traffic load of the overloaded carrier is less than the first threshold value, the processor is further configured to:

determine whether the traffic load of the overloaded carrier is greater than a second threshold value, the second threshold value being less than the first threshold value; and

responsive to a determination that the traffic load of the overloaded carrier is greater than the second threshold value, equalize a combined traffic load of a plurality of carriers associated with the transceiver such that an individual traffic load of each of the plurality of the carriers is essentially equalized to a value less than the second threshold value, wherein the plurality of carriers includes the overloaded carrier.

27. The apparatus of claim 26, wherein at least one of the first threshold value or the second threshold value is a function of at least one of a plurality of threshold factors, the plurality of threshold factors comprising one or more parameters selected from the group consisting of:

a total number of users in communication with the transceiver using the plurality of carriers associated therewith, a total number of utilized time slots associated with the transceiver, a number of time slots allocated to each of the plurality of carriers, a service flow type associated with each of the plurality of carriers, a number of service flows associated with each of the plurality of carriers, and a modulation and coding scheme assigned to one or more users associated with each of the plurality of carriers.

28. The apparatus of claim 19, wherein the transceiver is configured to communicate with the plurality of users based on a 3G wireless technology.

29. The apparatus of claim 28, wherein the 3G wireless technology comprises CDMA/EvDO technology.

30. The apparatus of claim 19, wherein the transceiver is configured to communicate with the plurality of users based on a 4G wireless technology.

31. The apparatus of claim 30, wherein the 4G wireless technology comprises WiMAX technology.

32. The apparatus of claim 30, wherein the 4G wireless technology comprises LTE technology.

33. The apparatus of claim 19, wherein the transceiver is configured to communicate with the plurality of users using a multiple access scheme, the multiple access scheme comprising Orthogonal Frequency Division Multiple Access (OFDMA).

34. A non-transitory computer-readable medium comprising computer readable code physically embodied thereon which, when executed by a processor arranged in a first base station apparatus capable of operating in a wireless network, causes the processor to carry out the operations of:

calculating a load metric for each of a plurality of users, wherein each of the plurality of users, in operation, are in communication with the first base station using an overloaded carrier associated with the first base station, and wherein the load metric for each of the plurality of users comprises a plurality of metric factors related at least to an associated communication link;

determining a transfer-deserving user from the plurality of users, the transfer-deserving user being associated with a highest value of an associated calculated load metric; and

transferring the associated communication link of the transfer-deserving user from the overloaded carrier to a target carrier, wherein the target carrier is associated with either the first base station or a second base station.