Mobile Assisted Timing Alignment

• US 20070293157A1
• Filed: 06/20/2006
• Published: 12/20/2007
• Est. Priority Date: 06/20/2006
• Status: Abandoned Application

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Haartsen, Jacobus, Lindoff, Bengt
• Application Number:
  US11/425,324
• Publication Number:
  US 20070293157A1
• Time in Patent Office: Days
• US Class Current: 455/67.11
• CPC Class Codes: H04B 7/2681 Synchronisation of a mobile station with one base station
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time

Abstract

Timing alignment of User Equipment (UE) in a communications system is maintained by measuring an environmental condition of the UE, and determining a present magnitude of change metric representing a present magnitude of change of the environmental condition relative to a baseline value. The present magnitude of change metric is combined with a previous accumulation metric to obtain a present accumulation metric. If it is detected that the present accumulation metric satisfies a predetermined relationship with respect to the threshold value (e.g., is greater than the threshold value), then the UE transmits a timing advance request. An environmental condition can be, for example, a Doppler shift of a received signal, a Received Signal Strength Indication from a received signal, a temperature within the UE, a humidity within the UE, a supply voltage of the UE, or a symbol timing of a received signal.

Claims

1. A method of operating a User Equipment (UE), comprising:

measuring an environmental condition of the UE;

determining a present magnitude of change metric representing a present magnitude of change of the environmental condition relative to a baseline value;

combining the present magnitude of change metric with a previous accumulation metric to obtain a present accumulation metric;

detecting whether the present accumulation metric satisfies a predetermined relationship with respect to a threshold value;

if it is detected that the present accumulation metric satisfies the predetermined relationship with respect to the threshold value, then transmitting a timing advance request.

2. The method of claim 1, wherein:

measuring the environmental condition comprises measuring a Doppler shift of a received signal; and

the baseline metric is zero.

3. The method of claim 1, wherein:

measuring the environmental condition comprises determining a Received Signal Strength Indication from a received signal; and

the baseline metric is a Received Signal Strength Indication value determined when a most recent timing advance update was performed.

4. The method of claim 1, wherein:

measuring the environmental condition comprises measuring a temperature within the UE; and

the baseline metric is a temperature value determined when a most recent timing advance update was performed.

5. The method of claim 1, wherein:

measuring the environmental condition comprises measuring a humidity within the UE; and

the baseline metric is a humidity value determined when a most recent timing advance update was performed.

6. The method of claim 1, wherein:

measuring the environmental condition comprises measuring a supply voltage of the UE; and

the baseline metric is a supply voltage value determined when a most recent timing advance update was performed.

7. The method of claim 1, wherein:

measuring the environmental condition comprises measuring a symbol timing of a received signal; and

the baseline metric is a symbol timing value determined when a most recent timing advance update was performed.

8. An apparatus for operating a User Equipment (UE), comprising:

logic adapted to measure an environmental condition of the UE;

logic adapted to determine a present magnitude of change metric representing a present magnitude of change of the environmental condition relative to a baseline value;

logic adapted to combine the present magnitude of change metric with a previous accumulation metric to obtain a present accumulation metric;

logic adapted to detect whether the present accumulation metric satisfies a predetermined relationship with respect to a threshold value;

logic adapted to transmit a timing advance request in response to it being detected that the present accumulation metric satisfies the predetermined relationship with respect to the threshold value.

9. The apparatus of claim 8, wherein:

the logic adapted to measure the environmental condition comprises logic adapted to measure a Doppler shift of a received signal; and

the baseline metric is zero.

10. The apparatus of claim 8, wherein:

the logic adapted to measure the environmental condition comprises logic adapted to determine a Received Signal Strength Indication from a received signal; and

the baseline metric is a Received Signal Strength Indication value determined when a most recent timing advance update was performed.

11. The apparatus of claim 8, wherein:

the logic adapted to measure the environmental condition comprises logic adapted to measure a temperature within the UE; and

the baseline metric is a temperature value determined when a most recent timing advance update was performed.

12. The apparatus of claim 8, wherein:

the logic adapted to measure the environmental condition comprises logic adapted to measure a humidity within the UE; and

the baseline metric is a humidity value determined when a most recent timing advance update was performed.

13. The apparatus of claim 8, wherein:

the logic adapted to measure the environmental condition comprises logic adapted to measure a supply voltage of the UE; and

the baseline metric is a supply voltage value determined when a most recent timing advance update was performed.

14. The apparatus of claim 8, wherein:

logic adapted to measure the environmental condition comprises logic adapted to measure a symbol timing of a received signal; and

the baseline metric is a symbol timing value determined when a most recent timing advance update was performed.