METHOD AND DEVICES FOR RADIO LINK MONITORING
A method for radio link monitoring includes: weighting a sequence of signal-to-noise ratios of the radio link with a weighting function of the sequence of signal-to-noise ratios; and monitoring an average of the weighted sequence of signal-to-noise ratios of the radio link.
1 . A method for radio link monitoring, the method comprising:
weighting a sequence of signal-to-noise ratios of a radio link with a weighting function of the sequence of signal-to-noise ratios; and
monitoring an average of the weighted sequence of signal-to-noise ratios of the radio link.
2 . The method of claim 1 , comprising:
detecting a synchronization event if the average of the weighted sequence of signal-to-noise ratios of the radio link crosses a threshold.
3 . The method of claim 1 , comprising:
determining the sequence of signal-to-noise ratios of the radio link based on a cell-specific reference signal.
4 . The method of claim 1 , comprising:
determining signal-to-noise ratios of at least one of a physical downlink control channel and a physical control format indicator channel as defined by LTE standardization.
5 . The method of claim 4 , comprising:
detecting a synchronization event if the average of the weighted sequence of signal-to-noise ratios of at least one of the physical downlink control channel and the physical control format indicator channel crosses a threshold.
6 . The method of claim 1 , comprising:
detecting a loss of synchronization state if the average of the weighted sequence of signal-to-noise ratios of the radio link falls below a threshold.
7 . The method of claim 6 , wherein the threshold is predetermined and stored in a lookup table.
8 . The method of claim 1 , wherein the weighting function is monotonically falling within a predetermined range of signal-to-noise ratios.
9 . The method of claim 1 , wherein the weighting function comprises a block error rate function of the sequence of signal-to-noise ratios.
10 . The method of claim 9 , comprising:
measuring a block error rate over a signal-to-noise ratio for a multi-path fading channel model according to one of the following channel models as defined in 3GPP TS 36.101:
AWGN,
ETU 30 Hz,
ETU 70 Hz,
ETU 300 Hz,
EVA 5 Hz,
EVA 70 Hz,
EPA 5 Hz,
High speed train, and
MBSFN
to obtain the weighting function.
11 . The method of claim 1 , comprising:
determining the average of the weighted sequence of signal-to-noise ratios of the radio link according to the relation:
A
=
1
K
∑
k
=
0
K
SNR
(
k
)
·
w
[
SNR
(
k
)
]
,
where A denotes the average, SNR(k) denotes the sequence of signal-to-noise ratios, k denotes an index of the sequence of signal-to-noise ratios, 0 and K are the borders of the sequence of signal-to-noise ratios, and w denotes a weighting of the sequence of signal-to-noise ratios.
12 . A radio link monitoring device, comprising:
a weighting unit configured for weighting a sequence of signal-to-noise ratios of a radio link with a weighting function of the sequence of signal-to-noise ratios; and
a monitoring unit configured for monitoring an average of the weighted sequence of signal-to-noise ratios of the radio link.
13 . The radio link monitoring device of claim 12 , comprising:
a signal-to-noise ratio measuring unit configured for measuring the sequence of signal-to-noise ratios.
14 . The radio link monitoring device of claim 12 , comprising at least one of:
a storage unit configured for storing the weighting function, and
a generation unit configured for generating the weighting function.
15 . A method for detecting synchronization events in a radio link, the method comprising:
determining a sequence of signal-to-noise ratios of the radio link;
weighting the sequence of signal-to-noise ratios of the radio link with a weighting function; and
detecting a synchronization event if an average of the weighted sequence of signal-to-noise ratios of the radio link crosses a threshold.
16 . The method of claim 15 , wherein the weighting function depends on the sequence of signal-to-noise ratios.
17 . The method of claim 15 , comprising:
accumulating the weighted sequence of signal-to-noise ratios to obtain the average of the weighted sequence of signal-to-noise ratios.
18 . The method of claim 15 , wherein the weighting function monotonically falls within a predetermined range around the threshold.
19 . The method of claim 15 , comprising:
detecting an out-of-sync state if the average of the weighted sequence of signal-to-noise ratios of the radio link falls below the threshold.
20 . The method of claim 15 ,
wherein the threshold with respect to an out-of-sync event corresponds to a block error rate of a first value of 10 percent; and
wherein the threshold with respect to an in-sync event corresponds to a block error rate of a second value of 2 percent.