Enhanced uplink rate selection by a communication device during soft handoff

• US 20040219920A1
• Filed: 04/30/2003
• Published: 11/04/2004
• Est. Priority Date: 04/30/2003
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Love, Robert T., Kuchibhotla, Ravi, Ghosh, Amitava, Whinnett, Nicholas W.
• Granted Patent: US 7,321,780 B2
• Time in Patent Office: Days
• US Class Current: 455/442
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/1671 the supervisory signal being transmitted together with control information
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 52/267 taking into account the information rate
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling

Abstract

A method for rate selection by a communication device for enhanced uplink during soft handoff in a wireless communication system includes a first step of receiving information from a scheduler. This information can included one or more of scheduling, a rate limit, a power margin limit, and a persistence. A next step includes determining a data rate for an enhanced uplink during soft handoff using the information. A next step includes transmitting to a serving base station on an enhanced uplink channel at the data rate determined from the determining step.

Claims

1. A method for rate selection by a communication device for uplink transmission during soft handoff in a wireless communication system, the method comprising steps of:

receiving information from a scheduler;

determining a data rate for an uplink transmission using the information; and

transmitting to a serving base station on an uplink channel at the data rate determined from the determining step.

2. The method of claim 1, wherein the receiving step includes receiving a rate limit from the serving base station, and the determining step includes using the rate limit and local channel conditions to determining the data rate for the uplink channel.

3. The method of claim 1, wherein the receiving step includes receiving a power margin limit from the serving base station, and the determining step includes using the power margin limit and local channel conditions to determining the data rate for the uplink channel.

4. The method of claim 2, wherein the receiving step includes receiving interference rise-over-thermal limits from a plurality of Active Set base stations, and wherein the determining step includes determining the highest rate that meets the rate limit and interference limits of the plurality of Active Set base stations given local conditions of the uplink channel.

5. The method of claim 2, wherein the receiving step includes receiving power control commands from a plurality of Active Set base stations and storing the received commands as a power control command history, and wherein the determining step includes determining the highest rate that meets the rate limit using the power control command history for the plurality of Active Set base stations.

6. The method of claim 2, wherein the receiving step includes receiving and measuring channel signal strength levels from a plurality of Active Set base stations and storing the strength levels, and wherein the determining step includes determining the highest rate that meets the rate limit using the stored channel signal strength levels for the plurality of Active Set base stations.

7. The method of claim 6, wherein the channel signal strength levels are the pilot channel signal strength levels.

8. The method of claim 6, wherein the channel signal strength levels are the Broadcast control channel (BCCH) signal strength levels.

9. The method of claim 1, wherein the receiving step includes receiving a rate limit from the scheduler for autonomous transmissions.

10. The method of claim 1, wherein the receiving step includes receiving a power margin limit from the scheduler for autonomous transmissions

11. The method of claim 9, wherein the receiving step includes receiving an persistence information on a control channel from the scheduler.

12. The method of claim 11, wherein the control channel is a common broadcast control channel.

13. The method of claim 11, wherein the receiving step includes receiving a maximum uplink data channel to pilot channel ratio, and the persistence value is based on rise-over-thermal information from the Active Set of base station cells.

14. The method of claim 11, wherein the receiving step includes receiving a maximum power margin, and the persistence value is based on rise-over-thermal information from the Active Set of base station.

15. The method of claim 1, wherein the receiving step includes receiving time constraints for autonomous transmissions from the scheduler, that splits the explicit scheduling into separate times from autonomous scheduling.

16. The method of claim 15, wherein the time constraints for autonomous transmissions from the scheduler are determined based on the number of users in autonomous mode.

17. The method of claim 15, wherein the time constraints for autonomous transmissions are determined based on the number of users in explicit scheduling mode.

18. The method of claim 15, wherein the time constraints for autonomous transmissions are determined based on the buffer occupancy of the autonomous mode and explicit scheduling mode users.

19. A method for rate selection by a communication device for uplink during soft handoff in a communication system, the method comprising steps of:

receiving a scheduling assignment message including a power margin limit from a scheduler;

determining a data rate for an uplink transmission during soft handoff using the power margin limit, local channel conditions and a buffer occupancy of the communication device; and

transmitting to a serving base station on an uplink channel at the data rate determined from the determining step.

20. The method of claim 19, wherein the receiving step includes receiving a scheduling assignment message including a rate limit from a scheduler.

21. The method of claim 19, wherein the determining step includes determining a maximum rate for an enhanced uplink during soft handoff using the rate limit, local channel conditions and a buffer occupancy of the communication device.

22. The method of claim 19, wherein the receiving step includes receiving an interference rise-over-thermal requirement from the serving Active Set base station and a plurality of adjacent Active Set base stations, and wherein the determining step includes determining the highest rate that meets the received power margin limit and interference limits given local conditions of the uplink channel.

23. The method of claim 19, wherein the receiving step includes receiving power control commands from the serving Active Set base station and a plurality of Active Set base stations and storing the received commands as a power control command history, and wherein the determining step includes determining the highest rate that meets the power margin limit using the power control command history for the Active Set base stations.

24. The method of claim 19, wherein the receiving step includes receiving and measuring common pilot channel signal strength levels from a plurality of adjacent Active Set base stations and storing the strength levels, and wherein the determining step includes determining the highest rate that meets the power margin limit using the stored common pilot channel signal strength levels for the plurality of Active Set base stations.

25. The method of claim 19, wherein the determining step includes a data rate constraint of

K2*P_margin—

_limit/P_dpcch*TPC_correction

where P<sub>margin—

limit</sub> is the power margin limit, P_dpcch is a power of the downlink physical control channel, and K2 is a scale factor, and TPC_correction dependent upon a power control command history and pilot channel signal strength.

26. The method of claim 19, wherein the determining step includes updating the power margin limit to account for changes in a serving cell reverse link interference rise-over-thermal.

27. The method of claim 19, wherein the determining step includes a data rate constraint of

R_max—

<sub>effective—

SHOtarget</sub>*g(imbalance)

where R<sub>max—

effective—

SHOtarget</sub> is the maximum effective rate, and g(imbalance) is an imbalance between a transmission gain of the scheduling cell and communication device, divided by a transmission gain between an adjacent cell with next largest or largest transmission gain relative to scheduling cell and the communication device.

28. A method for rate selection by a communication device for enhanced uplink during soft handoff in a UMTS communication system, the method comprising steps of:

receiving a scheduling assignment message including a a power margin limit from a scheduling base station;

determining a maximum data rate for an enhanced uplink during soft handoff using the power margin limit, local channel conditions and a buffer occupancy of the communication device; and

transmitting to a serving base station on an enhanced uplink channel at the data rate determined from the determining step.

29. The method of claim 28, wherein the receiving step includes receiving a scheduling assignment message including a rate limit from a scheduling base station.

30. The method of claim 28, wherein the determining step includes determining a maximum rate for an enhanced uplink during soft handoff using the rate limit, local channel conditions and a buffer occupancy of the communication device.

31. The method of claim 28, wherein the receiving step includes receiving interference rise-over-thermal limits from a scheduling base station and a plurality of Active Set base stations, and wherein the determining step includes determining the highest rate that meets the power margin limit and interference limits of the scheduling base station and plurality of Active Set base stations given local conditions of the enhanced uplink channel.

32. The method of claim 28, wherein the receiving step includes receiving power control commands from the scheduling base station and a plurality of Active Set base stations and storing the received commands as a power control command history, and wherein the determining step includes determining the highest rate that meets the power margin limit using the power control command history for the scheduling base station and the plurality of Active Set base stations.

33. The method of claim 28, wherein the receiving step includes receiving and measuring common pilot channel signal strength levels from the scheduling base station and a plurality of Active Set base stations and storing the strength levels, and wherein the determining step includes determining the highest rate that meets the power margin limit using the stored common pilot channel signal strength levels for the scheduling base station and plurality of Active Set base stations.