SCHEDULING BASED ON RISE-OVER-THERMAL IN A WIRELESS COMMUNICATION SYSTEM

• US 20080198802A1
• Filed: 02/14/2008
• Published: 08/21/2008
• Est. Priority Date: 02/16/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sambhwani, Sharad Deepak, Zhang, Danlu, Mohanty, Bibhu
• Granted Patent: US 8,515,466 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 72/52 based on load
• CPC Class Codes: H04W 72/569 of the traffic information

Abstract

Techniques for scheduling users for transmission on the uplink in a wireless communication system are described. In one design, a total load for a cell may be determined based on a rise-over-thermal (RoT) measurement. An in-cell load for users served by the cell may be determined based on uplink transmissions received from these users. An outside load due to users in neighbor cells may be determined based on the total load and the in-cell load. A target total load for the cell may be determined based on a target RoT for the cell. An available load for the cell may be determined based on the target total load for the cell and the outside load. Users in the cell may be scheduled for transmission on the uplink based on the available load for the cell.

Claims

1. An apparatus for wireless communication, comprising:

at least one processor configured to determine an outside load due to users in neighbor cells, to determine an available load for a cell based on a target total load for the cell and the outside load, and to schedule users in the cell for transmission on uplink based on the available load for the cell; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the at least one processor is configured to determine a total load for the cell based on a rise-over-thermal (RoT) measurement, to determine an in-cell load for users served by the cell, and to determine the outside load based on the total load and the in-cell load.

3. The apparatus of claim 2, wherein the at least one processor is configured to determine a non-serving active set load for non-served users not served by the cell but having the cell in active sets of the users, and to determine the outside load based further on the non-serving active set load.

4. The apparatus of claim 2, wherein the at least one processor is configured to filter the outside load to obtain a filtered outside load, and to determine the available load based on the target total load and the filtered outside load.

5. The apparatus of claim 2, wherein the at least one processor is configured to determine a load of each user served by the cell, and to determine the in-cell load based on loads of all users served by the cell.

6. The apparatus of claim 5, wherein the at least one processor is configured to determine a pilot-energy-per-chip-to-total-noise ratio of each user served by the cell, to determine a total-energy-per-chip-to-total-noise ratio of each user based on the pilot-energy-per-chip-to-total-noise ratio and at least one of a traffic-to-pilot ratio and an overhead-to-pilot ratio for the user, and to determine the load of each user based on the total-energy-per-chip-to-total-noise ratio of the user.

7. The apparatus of claim 3, wherein the at least one processor is configured to generate relative grants for the non-served users based on the non-serving active set load and the in-cell load.

8. The apparatus of claim 2, wherein the at least one processor is configured to obtain a thermal noise measurement, to obtain a total received power measurement, and to obtain the RoT measurement based on the thermal noise measurement and the total received power measurement.

9. The apparatus of claim 8, wherein the at least one processor is configured to obtain the thermal noise measurement based on a signal measurement for a sideband between carriers.

10. The apparatus of claim 8, wherein the at least one processor is configured to obtain the thermal noise measurement based on a signal measurement made during a silence period with no users transmitting on the uplink.

11. The apparatus of claim 1, wherein the at least one processor is configured to determine the target total load for the cell based on a target rise-over-thermal (RoT).

12. The apparatus of claim 1, wherein the at least one processor is configured to allocate the available load to dedicated channels assigned to users before new transmissions, to determine a load due to the dedicated channels, and to update the available load by subtracting the load due to the dedicated channels.

13. The apparatus of claim 1, wherein the at least one processor is configured to allocate the available load to retransmissions before new transmissions, to determine a load due to the retransmissions, and to update the available load by subtracting the load due to the retransmissions.

14. The apparatus of claim 1, wherein the at least one processor is configured to allocate the available load to autonomous transmissions by users before new transmissions, to determine a load due to the autonomous transmissions, and to update the available load by subtracting the load due to the autonomous transmissions.

15. The apparatus of claim 1, wherein the at least one processor is configured to determine priorities of the users to be scheduled in the cell, to sort the users based on the priorities, and to allocate the available load to the sorted users, one user at a time, starting with a highest priority user.

16. The apparatus of claim 1, wherein the at least one processor is configured to assign a data rate to a user being scheduled, to determine a load of the user based on the assigned data rate, and to update the available load by subtracting the load of the user.

17. The apparatus of claim 16, wherein the at least one processor is configured to determine the assigned data rate for the user based on a power headroom and a queue size of the user.

18. The apparatus of claim 1, wherein the at least one processor is configured to assign reserved data rates to the users to be scheduled in the cell, to determine a load due to the reserved data rates, to update the available load by subtracting the load due to the reserved data rates, and to allocate the updated available load to the users to be scheduled in the cell.

19. The apparatus of claim 1, wherein the at least one processor is configured to schedule the users in the cell for transmission on the uplink with High-Speed Uplink Packet Access (HSUPA).

20. A method for wireless communication, comprising:

determining an outside load due to users in neighbor cells;

determining an available load for a cell based on a target total load for the cell and the outside load; and

scheduling users in the cell for transmission on uplink based on the available load for the cell.

21. The method of claim 20, wherein the determining the outside load comprises

determining a total load for the cell based on a rise-over-thermal (RoT) measurement,

determining an in-cell load for users served by the cell, and

determining the outside load based on the total load and the in-cell load.

22. The method of claim 21, wherein the determining the outside load further comprises

determining a non-serving active set load for users not served by the cell but having the cell in active sets of the users, and

determining the outside load based further on the non-serving active set load.

23. The method of claim 21, wherein the determining the in-cell load comprises

determining a load of each user served by the cell, and

determining the in-cell load based on loads of all users served by the cell.

24. The method of claim 21, further comprising:

obtaining a thermal noise measurement;

obtaining a total received power measurement; and

obtaining the RoT measurement based on the thermal noise measurement and the total received power measurement.

25. The method of claim 20, wherein the scheduling the users in the cell comprises

assigning a data rate to a user being scheduled,

determining a load of the user based on the assigned data rate, and

updating the available load by subtracting the load of the user.

26. An apparatus for wireless communication, comprising:

means for determining an outside load due to users in neighbor cells;

means for determining an available load for a cell based on a target total load for the cell and the outside load; and

means for scheduling users in the cell for transmission on uplink based on the available load for the cell.

27. The apparatus of claim 26, wherein the means for determining the outside load comprises

means for determining a total load for the cell based on a rise-over-thermal (RoT) measurement,

means for determining an in-cell load for users served by the cell, and

means for determining the outside load based on the total load and the in-cell load.

28. The apparatus of claim 27, wherein the means for determining the outside load further comprises

means for determining a non-serving active set load for users not served by the cell but having the cell in active sets of the users, and

means for determining the outside load based further on the non-serving active set load.

29. The apparatus of claim 27, wherein the means for determining the in-cell load comprises

means for determining a load of each user served by the cell, and

means for determining the in-cell load based on loads of all users served by the cell.

30. The apparatus of claim 27, further comprising:

means for obtaining a thermal noise measurement;

means for obtaining a total received power measurement; and

means for obtaining the RoT measurement based on the thermal noise measurement and the total received power measurement.

31. The apparatus of claim 26, wherein the means for scheduling the users in the cell comprises

means for assigning a data rate to a user being scheduled,

means for determining a load of the user based on the assigned data rate, and

means for updating the available load by subtracting the load of the user.

32. A computer program product, comprising:

a computer-readable medium comprising;

code for causing at least one computer to determine an outside load due to users in neighbor cells;

code for causing the at least one computer to determine an available load for a cell based on a target total load for the cell and the outside load; and

code for causing the at least one computer to schedule users in the cell for transmission on uplink based on the available load for the cell.

33. The computer program product of claim 32, the computer-readable medium further comprising:

code for causing the at least one computer to determine a total load for the cell based on a rise-over-thermal (RoT) measurement;

code for causing the at least one computer to determine an in-cell load for users served by the cell; and

code for causing the at least one computer to determine the outside load based on the total load and the in-cell load.

34. The computer program product of claim 32, the computer-readable medium further comprising:

code for causing the at least one computer to assign a data rate to a user being scheduled;

code for causing the at least one computer to determine a load of the user based on the assigned data rate; and

code for causing the at least one computer to update the available load by subtracting the load of the user.

35. An apparatus for wireless communication, comprising:

at least one processor configured to send a request for transmission on uplink to a cell, to receive a grant for transmission on the uplink from the cell, and to send a transmission on the uplink in accordance with the grant, the grant being determined based on an available load for the cell, the available load being determined based on a target total load for the cell and an outside load due to users not in the cell; and

a memory coupled to the at least one processor.

36. The apparatus of claim 35, wherein the at least one processor is configured to send at least one dedicated channel to the cell, and wherein the available load is determined based further on a load due to dedicated channels of users in the cell.

37. The apparatus of claim 35, wherein the at least one processor is configured to send a retransmission of a pending packet to the cell, and wherein the available load is determined based further on a load due to retransmissions of users in the cell.

38. The apparatus of claim 35, wherein the at least one processor is configured to autonomously send a transmission to the cell without being scheduled, and wherein the available load is determined based further on a load due to autonomous transmissions of users in the cell.

39. A method for wireless communication, comprising:

sending a request for transmission on uplink to a cell;

receiving a grant for transmission on the uplink from the cell, the grant being determined based on an available load for the cell, the available load being determined based on a target total load for the cell and an outside load due to users not in the cell; and

sending a transmission on the uplink in accordance with the grant.

40. The method of claim 39, further comprising:

sending at least one dedicated channel to the cell, and wherein the available load is determined based further on a load due to dedicated channels of users in the cell.

41. The method of claim 39, further comprising:

sending a retransmission of a pending packet to the cell, and wherein the available load is determined based further on a load due to retransmissions of users in the cell.

42. The method of claim 39, further comprising:

autonomously sending a transmission to the cell without being scheduled, and wherein the available load is determined based further on a load due to autonomous transmissions of users in the cell.