Methods and apparatuses for positioning in a wireless communications network
The present disclosure relates to methods and apparatuses for improving positioning of a device in a wireless communications network. An example method, performed by a measuring device configured to communicate with a positioning device, includes determining a cross-correlation between a received signal and a transmitted reference signal; determining a channel impulse response (CIR) of the cross-correlation related to a first lobe detected above a selected threshold in the CIR; analyzing a temporal behavior of reflecting clusters/objects based on determined CIR instances of a time-of-arrival (TOA); classifying the reflecting clusters/objects based at least on their temporal behavior; and reporting at least one classified reflecting cluster/object to the positioning device.
1 . A method performed by a measuring device configured to communicate with a positioning device, the method comprising:
determining a cross-correlation between a received signal and a transmitted reference signal;
determining a channel impulse response (CIR) of the cross-correlation, related to a first lobe detected above a selected threshold in the CIR;
analyzing a temporal behavior of reflecting clusters/objects based on determined CIR instances of a time-of-arrival (TOA);
classifying the reflecting clusters/objects based at least on their temporal behavior; and
reporting at least one classified reflecting cluster/object to the positioning device.
2 . The method according to claim 1 , further comprising, for a reflecting cluster/object, predicting a TOA including a first lobe based on the classified reflecting clusters/objects.
3 . The method according to claim 1 , wherein a truncated part of the CIR includes a selected number of samples around a first arrival path included in the first lobe in the CIR.
4 . The method according to claim 3 , wherein the classifying the reflecting clusters/objects is further based on a quality value.
5 . The method according to claim 4 , wherein the quality value comprises a signal quality parameter including an indication on a noise and interference level.
6 . The method according to claim 5 , wherein the signal quality parameter is measured according to:
Quality
A
=
2
0
*
log
10
(
Amplitude
of
lobe
maximum
∑
i
=
0
n
amplitude
of
preceding
corrindx
n
)
wherein Amplitude of lobe maximum corresponds to an amplitude of a maximum lobe of the CIR or to a peak corresponding to the first lobe;
wherein amplitude of preceding corrindx corresponds to at least one amplitude of at least one value in a CIR part preceding the truncated part of the CIR; and wherein corrindx is a sample index of the CIR;
wherein n is an average number of samples.
7 . The method according to claim 4 , further comprising:
measuring a distance between a rising edge and a falling edge of the detected first lobe in the truncated part of the CIR;
determining the quality value within the first lobe, wherein the quality value indicates an expected error in a TOA estimate; and
reporting the quality value to the positioning device.
8 . The method according to claim 4 , wherein the quality value comprises a channel quality value, and the channel quality value is determined as at least one of a function of a power in a part of the CIR subsequent to the truncated part of the CIR, relative to the power in the truncated part of the CIR, and a function of a root-mean-square (RMS) delay spread of the truncated part of the CIR; and
wherein the method further comprises reporting the determined channel quality value to the positioning device.
9 . The method according to claim 1 , wherein the selected threshold is selected based on at least one of an estimated noise floor and a maximum value of the CIR.
10 . The method according to claim 1 , wherein a reflecting cluster/object is classified into one of a moving reflecting cluster/object and a fixed reflecting cluster/object; and the reporting at least one classified reflecting cluster/object to the positioning device comprises reporting at least one fixed reflecting cluster/object.
11 . The method according to claim 1 , further comprising receiving, from the positioning device, a request for capabilities of the measuring device and providing the positioning device with the requested capabilities.
12 . The method according to claim 1 , further comprising measuring a relative time t 4 MP from a first arrival path to the at least one reflecting cluster/object at one or more time instants, wherein the relative time t 4 MP is given by:
t
4
MP
=
t
4
+
t
c
1
where t 4 is a signal reception time at the measuring device and t c1 is a time delay, caused by the at least one reflecting cluster/object, to the first arrival path.
13 . The method according to claim 12 , further comprising receiving a request from the positioning device requesting relative time measurements to at least one identified reflecting cluster/object by providing at least a relative time t 2 MP to the first arrival path for enabling the positioning device to compute the relative time t 2 MP given by
t
2
MP
=
t
2
+
t
c
1
where t 2 is a signal reception time at the positioning device and t c1 is a time delay, caused by at least one identified reflecting cluster/object, to the first arrival path.
14 . The method according to claim 1 , wherein the first lobe includes the first arrival path and at least two samples defining at least one of a rising edge and a falling edge of the first lobe.
15 . A measuring device configured to communicate with a positioning device, the measuring device comprising a processor and a memory containing instructions executable by the processor whereby the measuring device is operative to:
determine a cross-correlation between a received signal and a transmitted reference signal;
determine a channel impulse response (CIR) of the cross-correlation related to a first lobe detected above a selected threshold in the CIR;
analyze a temporal behavior of reflecting clusters/objects based on determined CIR instances of a time-of-arrival (TOA);
classify the reflecting clusters/objects based at least on their temporal behavior; and
report at least one classified reflecting cluster/object to the positioning device.
16 . The measuring device according to claim 15 , wherein the measuring device is a user equipment (UE) configured to communicate with the positioning device over an LTE positioning protocol (LPP) interface, and the UE is configured to communicate with the positioning device over a sidelink interface.
17 . The measuring device according to claim 15 , wherein the measuring device is a network node configured to communicate with the positioning device over a New Radio Positioning Protocol A (NRPPa) interface.
18 . A method performed by a positioning device configured to communicate with a measuring device, wherein a cross-correlation between a received signal and a transmitted reference signal by the measuring device is determined, and a channel impulse response (CIR) of the cross-correlation related to a first lobe detected above a selected threshold in the CIR is determined, the method comprising:
receiving a report indicating at least one classified reflecting cluster/object from the measuring device, wherein reflecting clusters/objects are classified based at least on their temporal behavior, and the temporal behavior of the reflecting clusters/objects is analyzed based on determined CIR instances of a time-of-arrival (TOA).
19 . A positioning device configured to communicate with a measuring device, wherein a cross-correlation between a received signal and a transmitted reference signal by the measuring device is determined, and a channel impulse response (CIR) of the cross-correlation related to a first lobe detected above a selected threshold in the CIR is determined, the positioning device comprising a processor and a memory containing instructions executable by the processor whereby the positioning device is operative to:
receive a report indicating at least one classified reflecting cluster/object from the measuring device, wherein reflecting clusters/objects are classified based at least on their temporal behavior, and the temporal behavior of the reflecting clusters/objects is analyzed based on determined CIR instances of a time-of-arrival (TOA).
20 . The positioning device according to claim 19 , the positioning device including a Location Management Function.