System and method for measurement report time stamping to ensure reference time correctness

• US 7,519,033 B2
• Filed: 05/03/2004
• Issued: 04/14/2009
• Est. Priority Date: 05/09/2003
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Soomro, Amjad
• Primary Examiner(s): Afshar; Kamran
• Application Number:
  US10/556,001
• Publication Number:
  US 20070002806A1
• Time in Patent Office: 1,807 Days
• Field of Search: 370/310, 370/328, 370277-278, 370/332, 370345-350, 455/67.11, 455/67.14, 455/115.1, 455/524, 455/502, 455/507, 455/41.2, 455/423
• US Class Current: 370/338
• CPC Class Codes: H04L 43/067 using time frame reporting
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A system and method is provided that resolves a possible ambiguity in WLAN measurement reports by having a measuring entity include timer values in returned measurement reports. The time a measurement was requested to be performed and the actual time it was done by a measuring entity can be compared by the receiver to ensure that no ambiguities occurred.

Claims

1. A method for creating a measurement report among a plurality of stations in a wireless local area network (WLAN), comprising the steps of:

receiving by a measurement capable station of said plurality of stations a measurement request for at least one measurement report element to be made at a given time;

recording by the measurement capable station said at least one measurement report element;

creating by the measurement capable station a measurement report comprising said at least one measurement report element as one of measurement report elements contained therein;

respectively time-stamping with an absolute time reference at least one of said at least one recorded measurement report element and said measurement report; and

transmitting by the measurement capable station said created measurement report.

2. The method of claim 1, wherein said time-stamping step further comprises the step of setting by the measurement capable station each said absolute time reference to a time synchronization function (TSF) timer value.

3. The method of claim 1, further comprising the steps of:

if at least one measurement element has been time-stamped with an absolute time reference, determining by the measurement capable station an earliest said absolute time reference of a measurement report element, and setting by the measurement capable station said measurement report time-stamp to said determined earliest absolute time reference of a measurement report element.

4. The method of claim 3, wherein said time-stamping step further comprises the step of setting by the measurement capable station each said absolute time to a time synchronization function (TSF) timer value (306).

5. A method for creating an autonomous measurement report having at least one measurement report element, among a plurality of stations in a wireless local area network, comprising the steps of:

recording by a measurement capable station of said plurality of stations at least one pre-determined measurement report element;

optionally time-stamping with an absolute time reference by the measurement capable station said at least one recorded measurement report element;

creating by the measurement capable station an autonomous measurement report comprising said at least one measurement report element;

optionally time-stamping with an absolute time reference of the earliest time of a measurement report element contained therein said autonomous measurement report, and

transmitting by the measurement capable station said autonomous measurement report, wherein, at least one of said autonomous measurement report time-stamp and said at least one measurement report element time-stamp is included in said autonomous measurement report.

6. The method of claim 5, wherein each said time-stamping step further comprises the step of setting by the measurement capable station said absolute time-stamp to a time synchronization function (TSF) timer value.

7. A method for ensuring correctness of a time reference of a requested measurement among a plurality of stations (STAs) in a wireless local area network (WLAN), comprising the steps of:

transmitting by a first station a request for at least one time-stamped measurement report element to be performed at a given time;

receiving by a second station both the measurement request and a corresponding measurement report comprising the requested at least one measurement report element and at least one time-stamp comprising an absolute time reference of when the measurement recorded therein was done;

comparing by the second station the given time of the measurement request with the at least one time-stamp to determine correctness of the time-stamp.

8. The method of claim 7, wherein said receiving step further comprises the step of receiving a measurement report having each said Time Stamp set using a time synchronization function (TSF) timer value.

9. An apparatus configured for resource measurement among a plurality of stations in a wireless local area network (WLAN), comprising:

a receiver for receiving an incoming signal;

a measurement acquisition circuit that measures resources of said incoming signal received therein as at least one measurement report element;

a timer that provides an absolute time reference;

a control processor, coupled to said measurement acquisition circuit and said timer and beginning at a predetermined absolute time, configured to acquire at least one measurement report element of said incoming signal and optionally associate one of (1) an absolute time reference of the start of the first measurement reported within a measurement report as a time-stamp and (2) an absolute time reference of the start of each measurement report element reported therein with a measurement report element time-stamp.

10. The apparatus of claim 9, further comprising:

a memory, coupled to said control processor to store said obtained measurement report elements and optionally said associated measurement report element time-stamps; and

wherein, said control processor is further configured to compare the predetermined absolute time with at least one said absolute time-stamp to determine correctness of said at least one absolute time-stamp.

11. The apparatus of claim 9, further comprising a receiver for receiving a measurement request comprising at least one measurement request element to be measured and reported as a measurement report element and the predetermined time to staff measuring.

12. The apparatus of claim 11, wherein said measurement request is transmitted by a station of said plurality of stations.

13. The apparatus of claim 11, wherein said measurement request is transmitted by an access point of said plurality of stations.