Power-Aware Selection of Radio Access Technology

• US 20090068969A1
• Filed: 09/10/2007
• Published: 03/12/2009
• Est. Priority Date: 09/10/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Lindoff, Bengt, Haartsen, Jacobus Cornelis, Wallen, Anders
• Granted Patent: US 8,346,315 B2
• Time in Patent Office: Days
• US Class Current: 455/161.100
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Methods and apparatus are disclosed for operating a multi-mode wireless communications device to select a radio access technology (RAT) requiring the lowest energy consumption by the device for a desired operating mode. An exemplary method comprises scanning a plurality of frequency bands to determine a set of available radio access technologies that support the desired operating mode, and evaluating, for each available RAT, RAT-specific system parameters and RAT-specific operating conditions. Based on the evaluation, the RAT requiring the lowest energy consumption by the wireless device for the desired operating mode is selected.

Claims

1. A method of operating a multi-mode wireless communications device, comprising:

scanning one or more frequency bands to determine a set of available radio access technologies that support a desired operating mode;

for each radio access technology (RAT), evaluating RAT-specific system parameters and RAT-specific operating conditions; and

based on said evaluation, selecting a preferred RAT requiring the lowest energy consumption by the device for the desired operating mode.

2. The method of claim 1, wherein the RAT-specific operating conditions include a RAT-specific path loss and wherein evaluating RAT-specific system parameters and RAT-specific operating conditions includes evaluating said RAT-specific path loss.

3. The method of claim 1, wherein evaluating RAT-specific system parameters and RAT-specific operating conditions comprises determining an energy consumption metric for the desired operating mode based on the RAT-specific system parameters and RAT-specific operating conditions, and wherein selecting a preferred RAT is based on the determined energy consumption metrics.

4. The method of claim 3, wherein the RAT-specific system parameters for one or more RATs include a discontinuous reception (DRX) cycle parameter and wherein determining an energy consumption metric comprises determining the energy consumption metric as a function of the DRX cycle parameter.

5. The method of claim 3, wherein the RAT-specific system parameters for one or more RATs include a discontinuous transmission (DTX) cycle parameter and wherein determining an energy consumption metric comprises determining the energy consumption metric as a function of the DTX cycle parameter.

6. The method of claim 3, wherein the RAT-specific system parameters for one or more RATs include a cell deployment density and wherein determining an energy consumption metric comprises determining the energy consumption metric as a function of the cell deployment density.

7. The method of claim 3, further comprising determining a mobility parameter for the mobile wireless communications device, and wherein determining the energy consumption metric is further based on the mobility parameter.

8. The method of claim 3, wherein the RAT-specific system parameters for one or more RATs include a RAT-specific frequency band.

9. The method of claim 8, wherein determining an energy consumption metric comprises calculating a RAT-specific transmitter energy consumption estimate as a function of the RAT-specific frequency band and determining the energy consumption metric as a function of the RAT-specific transmitter energy consumption estimate.

10. The method of claim 9, further comprising determining a data throughput requirement for the desired operating mode, and wherein calculating a RAT-specific transmitter energy consumption estimate comprises calculating the RAT-specific transmitter energy consumption estimate as a function of the data throughput requirement.

11. The method of claim 1, wherein the desired operating mode is an idle mode, and wherein selecting a preferred RAT comprises identifying the available RAT requiring the lowest energy consumption in the idle mode and selecting that RAT for idle-mode camping, and further comprising camping on the preferred RAT.

12. The method of claim 11, wherein the preferred RAT is different from a current RAT, the method further comprising de-registering from the current RAT and registering at the preferred RAT, before camping on the preferred RAT.

13. The method of claim 1, wherein the desired mode is a mobile-initiated speech mode, and wherein selecting a preferred RAT comprises identifying the available RAT requiring the lowest energy consumption in the mobile-initiated speech mode and selecting that RAT for cell reselection, and further comprising initiating a cell reselection to the preferred RAT.

14. The method of claim 13, wherein initiating a cell reselection to the preferred RAT comprises de-registering from a current RAT and registering at the preferred RAT.

15. The method of claim 1, wherein the desired mode is a network-initiated speech mode, and wherein selecting a preferred RAT comprises identifying the available RAT requiring the lowest energy consumption in the network-initiated speech mode and selecting that RAT, and further comprising requesting an inter-RAT handover to the selected RAT.

16. The method of claim 1, wherein the desired mode is an ongoing voice call, further comprising determining whether the preferred RAT offers an improvement in energy consumption that meets a threshold requirement, and selectively requesting an inter-RAT handover based on that determination.

17. A multi-mode wireless communications device for operation with a plurality of radio access technologies (RATs), comprising:

a multi-mode radio section configured to scan one or more frequency bands to determine a set of available RATs supporting a desired operating mode and to determine one or more RAT-specific operating conditions; and

a control section configured to evaluate RAT-specific system parameters and the RAT-specific operating conditions for each available RAT and to select the RAT requiring the lowest energy consumption by the device for the desired operating mode.

18. The multi-mode wireless communications device of claim 17, wherein the one or more RAT-specific operating conditions include a RAT-specific path loss.

19. The multi-mode wireless communications device of claim 17, wherein the control section comprises a look-up table comprising energy consumption parameters associated with the desired operating mode and with the available RATs, and wherein the control section is configured to evaluate the RAT-specific system parameters and the RAT-specific operating conditions using the energy consumption parameters.

20. The multi-mode wireless communications device of claim 19, wherein the control section is further configured to update the energy consumption parameters in the look-up table responsive to a software upgrade adding or modifying an access technology capability.

21. The multi-mode wireless communications device of claim 17, wherein the control section is further configured to determine a mobility parameter for the mobile wireless communications device, and wherein the control section is configured to evaluate the RAT-specific system parameters and the RAT-specific operating conditions using the mobility parameter.

22. The multi-mode wireless communications device of claim 17, wherein the RAT-specific system parameters include a RAT-specific frequency band, and wherein the control section is configured to calculate a RAT-specific transmitter energy consumption requirement for each RAT as a function of the RAT-specific frequency band and to evaluate the RAT-specific system parameters and the RAT-specific operating conditions using the RAT-specific transmitter energy consumption requirement.

23. The multi-mode wireless communications device of claim 17, wherein the control section is further configured to initiate access to the preferred RAT.

24. The multi-mode wireless communications device of claim 23, wherein the control section is configured to initiate access to the selected RAT by initiating a cell-reselection to the preferred RAT.

25. The multi-mode wireless communications device of claim 23, wherein the control section is configured to initiate access to the selected RAT by requesting an inter-RAT handover to the preferred RAT.