Determining a signal quality using an error vector magnitude
Apparatuses, methods, and systems are disclosed for determining a signal quality using an error vector magnitude. One method includes receiving an output of a user equipment antenna port. The user equipment antenna port includes a linear combination of two or more transmit antennas. The method includes performing normalized maximum ratio combining on the output of the user equipment antenna port to produce a normalized output. The method includes determining a signal quality of the output of the user equipment antenna port. Determining the signal quality includes determining an error vector magnitude using the normalized output.
1. A method performed by an evaluation device, the method comprising:
receiving an output from an antenna port, wherein the antenna port comprises a linear combination of two or more transmit antennas;
performing normalized maximum ratio combining on the output of the antenna port to produce a normalized output; and
determining a signal quality of the output of the antenna port, wherein determining the signal quality comprises determining an error vector magnitude using the normalized output.
2. The method of claim 1 , wherein receiving the output of the antenna port comprises receiving the output using a separate conductive path from each transmit antenna of the two or more transmit antennas.
3. The method of claim 1 , wherein receiving the output of the antenna port comprises receiving the output using receive antenna ports, and each receive antenna port of the receive antenna ports comprises a linear combination of one or more receive antennas.
4. The method of claim 1 , wherein the normalized maximum ratio combining is given by
(
Hw
)
H
(
Hw
H
)
Hw
,
and wherein a vector w denotes linear combining weights comprising a transmit port, H is a channel matrix, and a term Hij in an i-th column and j-th row denotes a complex gain of a channel from a j-th transmit antenna to an i-th receive port.
5. The method of claim 1 , wherein a fast Fourier transform is computed for an output of each antenna connector.
6. The method of claim 5 , wherein the normalized maximum ratio combining is performed for each subcarrier of each allocated resource block based a channel estimate for each subcarrier for each antenna connector.
7. The method of claim 6 , wherein the normalized maximum ratio combining performed for each subcarrier is applied to a result of the fast Fourier transform.
8. The method of claim 7 , wherein the error vector magnitude is determined by comparing known data symbols with the normalized output.
9. An evaluation device, comprising:
at least one memory; and
at least one processor coupled with the at least one memory and configured to cause the evaluation device to:
receive an output from an antenna port, wherein the antenna port comprises a linear combination of two or more transmit antennas;
perform normalized maximum ratio combining on the output of the antenna port to produce a normalized output; and
determine a signal quality of the output of the antenna port, wherein determining the signal quality comprises determining an error vector magnitude using the normalized output.
10. The evaluation device of claim 9 , wherein the at least one processor is configured to cause the evaluation device to receive the output using a separate conductive path from each transmit antenna of the two or more transmit antennas.
11. The evaluation device of claim 9 , wherein the at least one processor is configured to cause the evaluation device to receive the output using receive antenna ports, and each receive antenna port of the receive antenna ports comprises a linear combination of one or more receive antennas.
12. The evaluation device of claim 9 , wherein the normalized maximum ratio combining is given by
(
Hw
)
H
(
Hw
H
)
Hw
,
denotes linear combining weights comprising a transmit port, H is a channel matrix, and a term Hij in an i-th column and j-th row denotes a complex gain of a channel from a j-th transmit antenna to an i-th receive port.
13. The evaluation device of claim 9 , wherein a fast Fourier transform is computed for an output of each antenna connector.
14. The evaluation device of claim 13 , wherein the normalized maximum ratio combining is performed for each subcarrier of each allocated resource block based a channel estimate for each subcarrier for each antenna connector.
15. The evaluation device of claim 14 , wherein the normalized maximum ratio combining performed for each subcarrier is applied to a result of the fast Fourier transform.
16. The evaluation device of claim 15 , wherein the error vector magnitude is determined by comparing known data symbols with the normalized output.
17. A processor for performing evaluations, comprising:
at least one controller coupled with at least one memory and configured to cause the processor to:
receive an output from an antenna port, wherein the antenna port comprises a linear combination of two or more transmit antennas;
perform normalized maximum ratio combining on the output of the antenna port to produce a normalized output; and
determine a signal quality of the output of the antenna port, wherein determining the signal quality comprises determining an error vector magnitude using the normalized output.
18. The processor of claim 17 , wherein the at least one controller is configured to cause the processor to receive the output using a separate conductive path from each transmit antenna of the two or more transmit antennas.
19. The processor of claim 17 , wherein the at least one controller is configured to cause the processor to receive the output using receive antenna ports, and each receive antenna port of the receive antenna ports comprises a linear combination of one or more receive antennas.
20. The processor of claim 17 , wherein the normalized maximum ratio combining is given by
(
Hw
)
H
(
Hw
H
)
Hw
,
and wherein a vector w denotes linear combining weights comprising a transmit port, H is a channel matrix of dimension M×N, and a term Hij in an i-th column and j-th row denotes a complex gain of a channel from a j-th transmit antenna to an i-th receive port.