METHODS AND SYSTEMS FOR CONTROLLING HANDOVERS IN A CO-CHANNEL NETWORK

• US 20130023302A1
• Filed: 07/12/2012
• Published: 01/24/2013
• Est. Priority Date: 07/21/2011
• Status: Active Grant

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Inventors: Sivanesan, Kathiravetpillai, Zou, Jialin, Vasudevan, Subramanian
• Granted Patent: US 8,977,268 B2
• Time in Patent Office: Days
• US Class Current: 455/525
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/324 by mobility data, e.g. speed data

Abstract

At least one example embodiment discloses a method of controlling a handover of a user equipment (UE) from a serving base station to a target base station in a heterogeneous network. The method includes determining, by a serving base station, a speed of the UE and a type of the handover, the type of the handover being one of macro cell to macro cell, macro cell to small cell, small cell to macro cell and small cell to small cell, and controlling, by the serving base station, the handover from the serving base station to the target base station based on the speed of the UE and the type of handover.

Claims

1. A method of controlling a handover of a user equipment (UE) from a serving base station to a target base station in a heterogeneous network, the method comprising:

determining, by a serving base station, a speed of the UE and a the type of the handover, the type of the handover being one of macro cell to macro cell, macro cell to small cell, small cell to macro cell and small cell to small cell; and

controlling, by the serving base station, the handover from the serving base station to the target base station based on the speed of the UE and the type of the handover.

2. The method of claim 1, wherein the controlling includes,

classifying the speed of the UE into one of a low speed, medium speed and high speed.

3. The method of claim 2, wherein the controlling includes,

preventing the handover to a small cell if the speed of the UE is the high speed, the target base station serving the small cell.

4. The method of claim 3, wherein the controlling includes,

scheduling the UE for transmission on almost blank sub-frames (ABS) of the target base station.

5. The method of claim 2, wherein the controlling includes,

increasing a handover threshold if the speed of the UE is the low speed, and

handing over the UE if the handover threshold exceeds a difference between the reference signal received power (RSRPs) of the target base station and the serving base station at the UE.

6. The method of claim 2, wherein the controlling includes,

decreasing a time-to-trigger (TTT) handover period if the speed of the UE is the high speed.

7. The method of claim 6, wherein the controlling includes,

decreasing a handover threshold if the speed of the UE is the high speed, and

handing over the UE if the handover threshold exceeds a difference between the reference signal received power (RSRPs) of the target and serving base stations at the UE.

8. The method of claim 2, wherein the controlling includes,

adjusting a handover threshold if the speed of the UE is the medium speed, and

handing over the UE if the handover threshold exceeds a difference between the reference signal received power (RSRPs) of the target and serving base stations at the UE.

9. The method of claim 1, wherein the controlling includes,

changing a handover threshold based on the speed of the UE, and

handing over the UE if the handover threshold exceeds a difference between the reference signal received power (RSRPs) of the target and serving base stations at the UE.

10. The method of claim 1, wherein the controlling includes,

changing a time-to-trigger (TTT) handover period based on the speed of the UE.

11. The method of claim 1, wherein the controlling includes,

adjusting a layer 3 filter ‘

K’

value based on the speed of the UE.

12. The method of claim 1, further comprising:

determining a direction of the UE, and the controlling includes,

controlling, by the serving base station, the handover from the serving base station to the target base station based on a velocity of the UE, the velocity being the speed and direction of the UE.

13. The method of claim 12, wherein the controlling includes,

classifying the speed of the UE into one of a low speed, medium speed and high speed.

14. The method of claim 13, wherein the controlling includes,

preventing the handover if the speed of the UE is the high speed.

15. The method of claim 12, wherein the controlling includes,

changing a handover threshold based on the velocity of the UE, and

handing over the UE if the handover threshold exceeds a difference between the reference signal received power (RSRPs) of the target and serving base stations at the UE.

16. The method of claim 12, wherein the controlling includes,

changing a time-to-trigger (TTT) handover period based on the velocity of the UE.

17. The method of claim 12, wherein the controlling includes,

adjusting a layer 3 filter K value based on the velocity of the UE.

18. The method of claim 1, wherein the controlling further includes,

changing a handover threshold based on the speed of the UE, the handover threshold being one of a cell specific offset of a cell associated with the target base station, a hysteresis parameter for an event and a system wide common offset parameter for the event.

19. The method of claim 1, wherein the controlling includes,

adjusting a layer 3 filter ‘

K’

value based on a type of handover, the type of handover being one of macro cell to macro cell, macro cell to small cell, small cell to macro cell and small cell to small cell.

20. The method of claim 1, wherein the controlling includes,

adjusting a time-to-trigger (TTT) handover period based on the type of the handover.

21. The method of claim 1, wherein the controlling includes,

scheduling the UE for transmission on almost blank sub-frames (ABS) of the target base station, and

handing over the UE to the target base station.

22. A base station configured to determine a speed of the UE in an area associated with the base station and control a handover from the base station to a target base station based on the speed of the UE and a type of the handover, the type of the handover being one of macro cell to macro cell, macro cell to small cell, small cell to macro cell and small cell to small cell.

23. A user equipment (UE) configured to perform handover measurements regarding a handover from a serving macro cell to a target small cell based on a velocity of the UE relative to the target cell.