Loopback testing in frequency division duplex systems

Patent metadata

Field	Value
Publication number	US-10193618-B2
Application number	US-201515553991-A
Country	US
Kind code	B2
Filing date	Mar 2, 2015
Priority date	Mar 2, 2015
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

A communication device and method therein for loopback testing. The device comprises a transmitter and a receiver and applies FDD for communication over one or more lines. The method comprises degrading a linearity of the transmitter, as compared to the linearity during normal operation. The method further comprises transmitting at least one test signal in a transmit frequency band, such that at least one signal is created in a receive frequency band, wherein the created at least one signal is a distortion product of the at least one test signal; and further, receiving a response to the at least one created signal in the receive frequency band.

First claim

The invention claimed is:

1. A method for loopback testing, performed by a device in a communication system, the device comprising a transmitter and a receiver and applying frequency division duplex (FDD) for communication, the method comprising:
degrading a linearity of the transmitter as compared to the linearity of the transmitter during normal operation by inducing one or more amplifiers of the transmitter to operate in a more non-linear region of their transfer function;
transmitting at least one test signal in a transmit frequency band, such that at least one signal is created in a receive frequency band, wherein the at least one created signal is a distortion product of the at least one test signal; and
receiving a response to the at least one created signal in the receive frequency band for performing loopback testing irrespective of a requirement for one or more additional switching circuitry to bypass transmit or receive filters.

2. The method according to claim 1 , wherein the degrading of the linearity of the transmitter comprises one or more of:
increasing a gain of one or more amplifiers in a transmitting chain;
amplifying the at least one test signal provided to one or more amplifiers in the transmitting chain;
reducing a supply voltage of one or more amplifiers in the transmitting chain; and
adjusting a bias of one or more amplifiers in the transmitting chain.

3. The method according to claim 1 , being a Time Domain Reflectometry method or a Frequency Domain Reflectometry method.

4. The method according to claim 1 , wherein the at least one created signal in the receive frequency band, being a distortion product, is a harmonic or an intermodulation product.

5. The method according to claim 1 , further comprising:
performing a calibration based on the at least one test signal.

6. A communication device for loopback testing, the communication device being operable in a communication system, and comprising a transmitter and a receiver and being configured to apply frequency division duplex (FDD) for communication, the communication device being further configured to:
degrade a linearity of the transmitter as compared to the linearity of the transmitter during normal operation by inducing one or more amplifiers of the transmitter to operate in a more non-linear region of their transfer function;
transmit at least one test signal in a transmit frequency band, such that at least one signal is created in a receive frequency band, wherein the at least one created signal is a distortion product of the at least one test signal; and
receive a response to the at least one created signal in the receive frequency band for performing loopback testing irrespective of a requirement for one or more additional switching circuitry to bypass transmit or receive filters.

7. The communication device according to claim 6 , being configured to degrade the linearity of the transmitter by one or more of:
increasing a gain of one or more amplifiers in a transmitting chain;
amplifying the at least one test signal provided to one or more amplifiers in the transmitting chain;
reducing a supply voltage of one or more amplifiers in the transmitting chain; and
adjusting a bias of one or more amplifiers in the transmitting chain.

8. The communication device according to claim 6 , wherein the at least one created signal in the receive frequency band, being a distortion product, is a harmonic or an intermodulation product.

9. The communication device according to claim 6 , being further configured to perform a calibration based on the at least one test signal.

10. A non-transitory computer readable storage medium comprising instructions which, when executed on at least one processor, cause a communication device comprising a transmitter and a receiver and applying frequency division duplex (FDD) for communication to perform loopback testing, comprising:
degrading a linearity of the transmitter as compared to the linearity of the transmitter during normal operation by inducing one or more amplifiers of the transmitter to operate in a more non-linear region of their transfer function;
transmitting at least one test signal in a transmit frequency band, such that at least one signal is created in a receive frequency band, wherein the at least one created signal is a distortion product of the at least one test signal; and
receiving a response to the at least one created signal in the receive frequency band for performing loopback testing irrespective of a requirement for one or more additional switching circuitry to bypass transmit or receive filters.

11. The non-transitory computer-readable storage medium according to claim 10 , wherein the instructions which, when executed on the at least one processor, further cause the degrading of the linearity of the transmitter by one or more of:
increasing a gain of one or more amplifiers in a transmitting chain;
amplifying the at least one test signal provided to one or more amplifiers in the transmitting chain;
reducing a supply voltage of one or more amplifiers in the transmitting chain; and
adjusting a bias of one or more amplifiers in the transmitting chain.

12. The non-transitory computer-readable storage medium according to claim 10 , wherein the instructions which, when executed on the at least one processor, cause loopback testing to be performed by a Time Domain Reflectometry method or a Frequency Domain Reflectometry method.

13. The non-transitory computer-readable storage medium according to claim 10 , wherein the instructions which, when executed on the at least one processor, further cause the at least one created signal in the receive frequency band, being a distortion product, to be a harmonic or an intermodulation product.

14. The non-transitory computer-readable storage medium according to claim 10 , wherein the instructions which, when executed on the at least one processor, further cause the communication device to perform a calibration based on the at least one test signal.

Assignees

• Ericsson Telefon Ab L M

Inventors

• Cederholm Daniel
• Trojer Elmar
• Berg Miguel

Classifications

• H04B10/071 Primary

  using a reflected signal, e.g. using optical time domain reflectometers [OTDR] · CPC title

• H04M3/30

  for subscriber's lines {, for the local loop} · CPC title

• H04B3/46 Primary

  Monitoring; Testing · CPC title

• H04L43/50

  Testing arrangements · CPC title

• H04M1/24

  Arrangements for testing · CPC title