ACCESS TERMINAL RADIO LINK MONITORING (RLM) ON A SHARED COMMUNICATION MEDIUM

• US 20180160328A1
• Filed: 11/30/2017
• Published: 06/07/2018
• Est. Priority Date: 12/01/2016
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: CHENDAMARAI KANNAN, Arumugam, RADULESCU, Andrei Dragos, PATEL, Chirag Sureshbhai, KADOUS, Tamer Adel, MANTRAVADI, Ashok, KHANDEKAR, Aamod
• Granted Patent: US 10,674,389 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04L 1/00 Arrangements for detecting or preventing errors in the information received correcting synchronisation H04L7/00
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 36/305 Handover due to radio link failure control signalling for hand-off failure H04W36/0079
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Techniques for access terminal radio link monitoring on a shared communication medium are disclosed. In an aspect, an access terminal detects a missed reference signal event associated with a radio link established on the shared communication medium, wherein detecting the missed reference signal event comprises determining that the access terminal did not detect a reference signal for measuring a quality of the radio link transmitted during a reference signal configuration window, assigns an error metric to the missed reference signal event based on reference signal monitoring capabilities of the access terminal, and triggers a radio link failure based on the assigned error metric. In an aspect, the missed reference signal event may be a missed Discovery Reference Signaling (DRS) event, the error metric may be a Block Error Rate (BLER) weight, and the reference signal for measuring the quality of the radio link comprises a Cell-specific Reference Signal (CRS).

Claims

1. A method for radio link monitoring on a shared communication medium, comprising:

detecting, by an access terminal, a missed reference signal event associated with a radio link established on the shared communication medium between the access terminal and an access point, wherein detecting the missed reference signal event comprises determining that the access terminal did not detect a reference signal for measuring a quality of the radio link transmitted during a reference signal configuration window;

assigning, by the access terminal, an error metric to the missed reference signal event based on reference signal monitoring capabilities of the access terminal; and

triggering, by the access terminal, a radio link failure based on the assigned error metric.

2. The method of claim 1, wherein the missed reference signal event comprises a missed Discovery Reference Signaling (DRS) event.

3. The method of claim 2, wherein the reference signal configuration window comprises a DRS Measurement Timing Configuration (DMTC) window.

4. The method of claim 1, wherein the reference signal for measuring the quality of the radio link comprises a Cell-specific Reference Signal (CRS).

5. The method of claim 1, wherein the error metric comprises a Block Error Rate (BLER) weight.

6. The method of claim 1, wherein the reference signal monitoring capabilities of the access terminal comprise a capability of the access terminal to monitor multiple Cell-specific Reference Signal (CRS) opportunities.

7. The method of claim 6, wherein the capability of the access terminal to monitor multiple CRS opportunities is indicated by a mf-MonitorTwoCRSScramblings parameter.

8. The method of claim 1, wherein the radio link comprises a Long-Term Evolution (LTE) in unlicensed spectrum radio link.

9. The method of claim 1, wherein assigning the error metric comprises:

assigning a first value to the error metric based on the access terminal being capable of monitoring multiple reference signal opportunities in multiple subframes of the radio link reserved for reference signal transmission; and

assigning a second value to the error metric based on the access terminal not being capable of monitoring multiple reference signal opportunities in multiple subframe of the radio link reserved for reference signal transmission,

wherein the first value is greater than the second value.

10. The method of claim 1, wherein assigning the error metric comprises:

assigning a first value to the error metric based on the missed reference signal event and cell searching reference signals not being detected; and

assigning a second value to the error metric based on the missed reference signal event and the cell searching reference signals being detected,

wherein the first value is greater than the second value.

11. The method of claim 10, wherein the cell searching reference signals comprise a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS).

12. The method of claim 1, wherein assigning the error metric is based on a number of detected reference signal events over a threshold number of reference signal configuration windows, wherein the number of detected reference signal events comprises a number of times the access terminal detected the reference signal for measuring the quality of the radio link transmitted during the threshold number of reference signal configuration windows.

13. The method of claim 1, wherein assigning the error metric comprises:

assigning a first value to the error metric based on the missed reference signal event and previous measurements of the radio link indicating that the radio link is a poor quality radio link; and

assigning a second value to the error metric based on the missed reference signal event and the previous measurements of the radio link indicating that the radio link is a good quality radio link,

wherein the first value is greater than the second value.

14. The method of claim 13, wherein the previous measurements of the radio link comprise a CRS Signal-to-Noise Ratio (SNR) and interference measurements.

15. The method of claim 1, wherein assigning the error metric is based on a Channel Quality Indicator (CQI) value for the radio link.

16. The method of claim 15, wherein based on the access terminal observing a QCI of value of 0 greater than a threshold number of times, a higher value of the error metric is assigned than is assigned based on the access terminal observing the QCI value of 0 less than the threshold number of times.

17. The method of claim 1, wherein based on a number of missed reference signal events over a threshold period of time being greater than a threshold, a higher value of the error metric is assigned than is assigned based on the access terminal detecting less than the threshold number of missed reference signal events over the threshold period of time.

18. The method of claim 1, wherein determining that the access terminal did not detect the reference signal for measuring the quality of the radio link comprises determining that the access terminal did not detect the reference signal before an end of the reference signal configuration window.

19. An apparatus for radio link monitoring on a shared communication medium, comprising:

at least one processor of an access terminal configured to;

detect a missed reference signal event associated with a radio link established on the shared communication medium between the access terminal and an access point, wherein detection of the missed reference signal event comprises a determination that the access terminal did not detect a reference signal for measuring a quality of the radio link transmitted during a reference signal configuration window;

assign an error metric to the missed reference signal event based on reference signal monitoring capabilities of the access terminal; and

trigger a radio link failure based on the assigned error metric.

20. The apparatus of claim 19, wherein the missed reference signal event comprises a missed Discovery Reference Signaling (DRS) event.

21. The apparatus of claim 19, wherein the reference signal for measuring the quality of the radio link comprises a Cell-specific Reference Signal (CRS).

22. The apparatus of claim 19, wherein the error metric comprises a Block Error Rate (BLER) weight.

23. The apparatus of claim 19, wherein the radio link monitoring capabilities of the access terminal comprise a capability of the access terminal to monitor multiple Cell-specific Reference Signal (CRS) opportunities.

24. The apparatus of claim 19, wherein the at least one processor being configured to assign the error metric comprises the at least one processor being configured to:

assign a first value to the error metric based on the access terminal being capable of monitoring multiple reference signal opportunities in multiple subframes of the radio link reserved for reference signal transmission; and

assign a second value to the error metric based on the access terminal not being capable of monitoring multiple reference signal opportunities in multiple subframe of the radio link reserved for reference signal transmission,

wherein the first value is greater than the second value.

25. The apparatus of claim 19, wherein the at least one processor being configured to assign the error metric comprises the at least one processor being configured to:

assign a first value to the error metric based on the missed reference signal event and cell searching reference signals not being detected; and

assign a second value to the error metric based on the missed reference signal event and the cell searching reference signals being detected,

wherein the first value is greater than the second value.

26. The apparatus of claim 19, wherein assignment of the error metric is based on a number of detected reference signal events over a threshold number of reference signal configuration windows, wherein the number of detected reference signal events comprises a number of times the access terminal detected the reference signal for measuring the quality of the radio link transmitted during the threshold number of reference signal configuration windows.

27. The apparatus of claim 19, wherein the at least one processor being configured to assign the error metric comprises the at least one processor being configured to:

assign a first value to the error metric based on the missed reference signal event and previous measurements of the radio link indicating that the radio link is a poor quality radio link; and

assign a second value to the error metric based on the missed reference signal event and the previous measurements of the radio link indicating that the radio link is a good quality radio link,

wherein the first value is greater than the second value.

28. The apparatus of claim 19, wherein based on a number of missed reference signal events over a threshold period of time being greater than a threshold, a higher value of the error metric is assigned than is assigned based on the access terminal detecting less than the threshold number of missed reference signal events over the threshold period of time.

29. An apparatus for radio link monitoring on a shared communication medium, comprising:

a means for processing of an access terminal configured to;

detect a missed reference signal event associated with a radio link established on the shared communication medium between the access terminal and an access point, wherein detection of the missed reference signal event comprises a determination that the access terminal did not detect a reference signal for measuring a quality of the radio link transmitted during a reference signal configuration window;

assign an error metric to the missed reference signal event based on reference signal monitoring capabilities of the access terminal; and

trigger a radio link failure based on the assigned error metric.

30. A non-transitory computer-readable medium storing computer-executable instructions for radio link monitoring on a shared communication medium, the computer-executable instructions comprising:

at least one instruction instructing an access terminal to detect a missed reference signal event associated with a radio link established on the shared communication medium between the access terminal and an access point, wherein detecting the missed reference signal event comprises determining that the access terminal did not detect a reference signal for measuring a quality of the radio link transmitted during a reference signal configuration window;

at least one instruction instructing the access terminal to assign an error metric to the missed reference signal event based on reference signal monitoring capabilities of the access terminal; and

at least one instruction instructing the access terminal to trigger a radio link failure based on the assigned error metric.