Polarized reception of reference signals at a terminal device
There is provided mechanisms for polarized reception of reference signals. A method is performed by a terminal device. The terminal device is equipped with an antenna array having dual-polarized antenna elements. The antenna array is connected to a baseband chain in the terminal device. The method comprises receiving, during a beam management procedure with a TRP, two reference signals transmitted in one OFDM symbol each from the same TRP port within a slot. The two reference signals are received using a filter with a first polarization for a first of the two reference signals and with a second polarization for a second of the two reference signals. The second polarization is orthogonal to the first polarization.
1. A method for polarized reception of reference signals, the method being performed by a terminal device, the method comprising:
performing a beam management procedure with a transmission and reception point (TRP) configured to transmit a first synchronization signal block (SSB) comprising a first reference signal and a second reference signal, wherein performing the beam management procedure comprises:
receiving the first reference signal transmitted; and
receiving the second reference signal, wherein
the first SSB is transmitted over one polarization,
the first reference signal is received using a filter with a first polarization,
the second reference signal is received using a filter with a second polarization, and
the second polarization is orthogonal to the first polarization.
2. The method of claim 1 , wherein the beam management procedure further comprises:
determining one common reference signal received power (RSRP) value from measurements as performed by the terminal device on both the first and second reference signals.
3. The method of claim 1 , wherein the first and second reference signals are received using one and the same beam at the terminal device.
4. The method of claim 1 , wherein the SSB further comprises a third reference signal and a fourth reference signal.
5. The method of claim 4 , wherein the one common RSRP value is determined from measurements as performed by the terminal device on the first, second, third, and fourth reference signals.
6. The method of claim 1 , wherein
the TRP is further configured to transmit a second SSB comprising a third reference signal and a fourth reference signal, and
the beam management procedure further comprises:
receiving the third reference signal using a filter with the first polarization,
receiving the fourth reference signal using a filter with the second polarization,
determining a first reference signal received power (RSRP) value from measurements as performed by the terminal device on both the first and second reference signals, and
determining a second RSRP value from measurements as performed by the terminal device on both the third and further reference signals.
7. The method of claim 6 , wherein the beam management procedure further comprises:
reporting which of the first and second SSBs was received with highest RSRP.
8. The method of claim 1 , wherein
the first reference signal is received using a first spatial beam pattern, and
the second reference signal is received using a second spatial beam pattern that is different from the first spatial beam pattern.
9. The method of claim 8 , wherein
the first spatial beam pattern has a first pointing direction and the second spatial beam pattern has a second pointing direction different from the first pointing direction, and/or
the first spatial beam pattern has a first width and the second spatial beam pattern has a second width different from the first width, and/or
the first spatial beam pattern is defined by a first set of N beams and the second spatial beam pattern is defined by a first set of M beams, where N does not equal M.
10. The method of claim 1 , wherein
each of the first polarization and the second polarization is defined by their own polarization state, which polarization state that defines each of the first polarization and the second polarization depends on rotational orientation of the terminal device, and
which polarization state that defines each of the first polarization and the second polarization remains unchanged as long as the rotational orientation of the terminal device remains unchanged.
11. A terminal device for polarized reception of reference signals, the terminal device comprising:
a baseband chain;
an antenna array having dual-polarized antenna elements, the antenna array being connected to the baseband chain; and
processing circuitry, the processing circuitry being configured to cause the terminal device to perform a method comprising:
performing a beam management procedure with a transmission and reception point (TRP) configured to transmit a first synchronization signal block (SSB) comprising a first reference signal and a second reference signal, wherein performing the beam management procedure comprises:
receiving the first reference signal transmitted; and
receiving the second reference signal, wherein
the first SSB is transmitted over one polarization,
the first reference signal is received using a filter with a first polarization,
the second reference signal is received using a filter with a second polarization, and
the second polarization is orthogonal to the first polarization.
12. The terminal device of claim 11 , wherein the beam management procedure further comprises:
determining one common reference signal received power (RSRP) value from measurements as performed by the terminal device on both the first and second reference signals.
13. The terminal device of claim 11 , wherein the first and second reference signals are received using one and the same beam at the terminal device.
14. The terminal device of claim 11 , wherein the SSB further comprises a third reference signal and a fourth reference signal.
15. The terminal device of claim 14 , wherein the one common RSRP value is determined from measurements as performed by the terminal device on the first, second, third, and fourth reference signals.
16. The terminal device of claim 11 , wherein
the TRP is further configured to transmit a second SSB comprising a third reference signal and a fourth reference signal, and
the beam management procedure further comprises:
receiving the third reference signal using a filter with the first polarization,
receiving the fourth reference signal using a filter with the second polarization,
determining a first reference signal received power (RSRP) value from measurements as performed by the terminal device on both the first and second reference signals, and
determining a second RSRP value from measurements as performed by the terminal device on both the third and further reference signals.
17. The terminal device of claim 16 , wherein the beam management procedure further comprises:
reporting which of the first and second SSBs was received with highest RSRP.
18. The terminal device of claim 11 , wherein
the first reference signal is received using a first spatial beam pattern, and
the second reference signal is received using a second spatial beam pattern that is different from the first spatial beam pattern.
19. The terminal device of claim 18 , wherein
the first spatial beam pattern has a first pointing direction and the second spatial beam pattern has a second pointing direction different from the first pointing direction, and/or
the first spatial beam pattern has a first width and the second spatial beam pattern has a second width different from the first width, and/or
the first spatial beam pattern is defined by a first set of N beams and the second spatial beam pattern is defined by a first set of M beams, where N does not equal M.
20. A non-transitory computer readable medium storing a computer program for polarized reception of reference signals, the computer program comprising computer code which, when run on processing circuitry of a terminal device equipped with an antenna array having dual-polarized antenna elements, the antenna array being connected to a baseband chain in the terminal device, causes the terminal device to perform a method comprising:
performing a beam management procedure with a transmission and reception point (TRP) configured to transmit a first synchronization signal block (SSB) comprising a first reference signal and a second reference signal, wherein performing the beam management procedure comprises:
receiving the first reference signal transmitted; and
receiving the second reference signal, wherein
the first SSB is transmitted over one polarization,
the first reference signal is received using a filter with a first polarization,
the second reference signal is received using a filter with a second polarization, and
the second polarization is orthogonal to the first polarization.