Polarization signaling in line-of-sight path detection
In an aspect, a first network node may receive, from a second network node, one or more reference signals transmitted using one or more first polarizations known to the first network node, wherein the one or more reference signals are received having one or more second polarizations. The first network node may determine whether the one or more reference signals followed a line-of-sight (LOS) path between the first network node and the second network node based on a comparison of signal characteristics related to the one or more first polarizations and signal characteristics related to the one or more second polarizations.
1. A method of determining a line-of-sight (LOS) condition performed by a first network node, comprising:
receiving, from a second network node, one or more reference signals transmitted using one or more first polarizations including one or more time-varying polarization patterns known to the first network node and a designated time over which the reference signals transmitted using the one or more first polarizations are transmitted, wherein the one or more reference signals are received having one or more second polarizations; and
determining whether the one or more reference signals followed a LOS path between the first network node and the second network node based on a comparison of signal characteristics related to the one or more first polarizations, and signal characteristics related to the one or more second polarizations, wherein the signal characteristics related to the one or more second polarizations includes a first received signal energy of the one or more reference signals along a first axis of polarization and a second received signal energy of the one or more reference signals along a second axis of polarization, wherein the first received energy and the second received energy are determined based on a time period longer than the designated period.
2. The method of claim 1 , further comprising:
receiving one or more polarization indicators indicating the one or more time-varying polarization patterns and one or more indicators indicating the designated time period.
3. The method of claim 2 , wherein:
the one or more polarization indicators indicate one or more antenna ports associated with the one or more time-varying polarization patterns.
4. The method of claim 2 , wherein the one or more polarization indicators and one or more indicators indicating the designated time period are received via:
Radio Resource Control (RRC) signaling;
one or more Control Elements (CE) of a Medium Access Control (MAC) layer; or
Downlink Control Information (DCI) of a Physical Downlink Control Channel (PDCCH).
5. The method of claim 2 , wherein the one or more polarization indicators comprise:
one or more polarization indicators indicating that the one or more first polarizations are one or more linear polarizations;
one or more polarization indicators indicating that the one or more first polarizations are one or more circular polarizations;
one or more polarization indicators indicating that the one or more first polarizations are one or more clockwise circular polarizations;
one or more polarization indicators indicating that the one or more first polarizations are one or more counterclockwise circular polarizations; or
one or more polarization indicators indicating that the one or more first polarizations are one or more elliptical polarizations.
6. The method of claim 1 , wherein the one or more time-varying polarization patterns of the one or more first polarizations comprise:
one or more time-varying polarization patterns of orthogonal linear polarizations;
one or more time-varying polarization patterns of linear polarizations having known phase offsets;
one or more time-varying polarization patterns of clockwise or counterclockwise circular polarizations; and
one or more time-varying polarization patterns of orthogonal elliptical polarizations.
7. The method of claim 1 , wherein:
the one or more time-varying polarization patterns of the one or more first polarizations includes one or more time-varying polarization patterns of linear polarizations, wherein the one or more time-varying polarization patterns of the linear polarizations are transmitted with one or more known phase offsets; and
determining whether the one or more reference signals followed the LOS path further comprises determining whether the one or more known phase offsets are preserved when the one or more reference signals are received at the first network node.
8. The method of claim 1 , wherein:
the first received signal energy and the second received signal energy are each based on an average signal energy.
9. A first network node, comprising:
a memory;
at least one transceiver; and
at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to:
receive, via the at least one transceiver, from a second network node, one or more reference signals transmitted using one or more first polarizations including one or more time-varying polarization patterns known to the first network node and a designated time over which the reference signals transmitted using the one or more first polarizations are transmitted, wherein the one or more reference signals are received having one or more second polarizations; and
determine whether the one or more reference signals followed a line-of-sight (LOS) path between the first network node and the second network node based on a comparison of signal characteristics related to the one or more first polarizations, and signal characteristics related to the one or more second polarizations, wherein the signal characteristics related to the one or more second polarizations include a first received signal energy of the one or more reference signals along a first axis of polarization and a second received signal energy of the one or more reference signals along a second axis of polarization, wherein the first received energy and the second received energy are determined based on a time period longer than the designated period.
10. The first network node of claim 9 , wherein the at least one processor is further configured to:
receive, via the at least one transceiver, one or more polarization indicators indicating the one or more first polarizations, one or more designated time indicators indicating the designated time, and one or more antenna ports associated with the one or more first polarizations.
11. The first network node of claim 10 , wherein the one or more polarization indicators and the one or more designated time indicators indicating the designated time are received via:
Radio Resource Control (RRC) signaling;
one or more Control Elements (CE) of a Medium Access Control (MAC) layer; or
Downlink Control Information (DCI) of a Physical Downlink Control Channel (PDCCH).
12. The first network node of claim 10 , wherein the one or more time-varying polarization patterns of the one or more first polarizations comprise:
one or more time-varying polarization patterns of orthogonal linear polarizations;
one or more time-varying polarization patterns of linear polarizations having known phase offsets;
one or more time-varying polarization patterns of clockwise or counterclockwise circular polarizations; and
one or more time-varying polarization patterns of orthogonal elliptical polarizations.
13. The first network node of claim 9 , wherein:
the first received signal energy and the second received signal energy are each based on an average signal energy.