Method and apparatus for virtual desktop OTA
The present invention relates to testing a mobile device in a lab by providing test signals to the mobile device via a cabled connection which bypasses the actual physical antennas in the mobile device. The test signals emulate a wireless channel and incorporate representative and/or actual measured characteristics of the performance of the antennas in the mobile device. As such, the performance mobile device can be accurately measured without requiring placement in an anechoic chamber, which enables efficient testing over a large set of configurations and underlying conditions.
1. A system for testing a mobile device having a set of two or more antennas, the system comprising:
memory storing representative radiation pattern data of individual antennas in the set, and storing a propagation channel model representing amplitude and angle of arrival of one or more signal paths between a signal source and the mobile device;
a channel emulator comprising one or more processors and storing instructions executable by the processors including instructions that cause the channel emulator to:
compute a modified propagation channel model, comprising modifying at least the amplitude of the individual signal paths using the radiation pattern data and an angular orientation parameter that relates the radiation pattern data of individual antennas in the set to the angle of arrival of the respective signal paths; and
generate a test signal to emulate a wireless channel between the signal source and the mobile device using the modified propagation channel model.
2. The system of claim 1 , wherein the representative radiation pattern data for the antennas in the set is based on measured data of the antennas in the set.
3. The system of claim 1 , wherein the representative radiation pattern data for the antennas in the set is based on a representative model of the antennas in the set.
4. The system of claim 1 , wherein said instructions that cause the channel emulator to compute the modified propagation channel model further comprises instructions that cause the channel emulator to modify the phase of individual signal paths at the angle of arrival of said individual signal paths.
5. The system of claim 1 , wherein said instructions to compute the modified propagation channel model further comprises instructions that cause the channel emulator to modify the signal paths to emulate spatial movement of the mobile device relative to the signal source.
6. The system of claim 5 , wherein said instructions that cause the channel emulator to modify the signal paths to emulate spatial movement includes instructions that cause the channel emulator to apply a Doppler spectrum based on a virtual spatial movement parameter that represents spatial movement of the mobile device relative to the signal source.
7. The system of claim 1 , wherein said memory further stores a second propagation channel model representing amplitude and angle of arrival of one or more second signal paths between a second signal source and the mobile device, the second signal source non-co-located with said signal source; and further comprising a second channel emulator coupled to the memory, the second channel emulator comprising one or more processors and storing instructions executable by the processors including instructions that cause the second channel emulator to:
to compute a second modified propagation channel model, comprising modifying at least the amplitude of individual second signal paths using the radiation pattern data and a second angular orientation parameter; and
generate a second test signal to emulate a second wireless channel between the signal source and the mobile device using the second modified propagation channel model.
8. The system of claim 7 , wherein the second channel emulator further stores instructions that cause the second channel emulator to provide the second test signal to a signal feed to emulate handover of the mobile device between first and second base stations.
9. The system of claim 7 , wherein the second channel emulator further stores instructions that cause the second channel emulator to provide the second test signal to a signal feed to emulate an interference source.
10. The system of claim 7 , wherein said test signal and second test signal are provided for an overlapping period of time.
11. The system of claim 1 , further comprising a test controller coupled to the channel emulator and the mobile device, for controlling operation of the channel emulator and the mobile device.
12. The system of claim 1 , wherein instructions that cause the channel emulator to compute the modified propagation channel model includes instructions that cause the channel emulator to modify the signal paths to emulate proximity of the mobile device to external objects.
13. The system of claim 1 , wherein the representative radiation pattern data stored in memory for the antennas in the set is based on measured data of the antennas in the set and includes proximity of the mobile device to external objects.
14. The system of claim 1 , wherein the amplitude and angle of arrival of the signal paths in the propagation channel model represent time-varying physical relationships between the signal source and the mobile device.
15. The system of claim 1 , wherein:
signal paths in the propagation channel model each comprise an associated plurality of signal sub-paths, the signal sub-paths representing sub-path amplitude, sub-path phase, and sub-path angle of arrival between the signal source and the mobile device; and
the channel emulator further including instructions that cause the channel emulator to:
compute modified sub-path component values, comprising modifying at least the sub-path amplitude of individual signal sub-paths using the radiation pattern data and an angular orientation parameter that relates the radiation pattern data of individual antennas in the set to the angle of arrival of the respective sub-paths; and
sum the modified sub-path component values of the sub-paths associated with a given signal path to compute the signal paths in the modified propagation channel model.
16. The system of claim 1 , wherein the propagation channel model represents the signal paths between a plurality of antennas at the signal source and the mobile device, wherein the signal paths are correlated in dependence upon antenna characteristics of the mobile device antennas.
17. A method for generating a test for a mobile device having a set of two or more antennas using one or more channel emulators including, the method comprising:
storing representative radiation pattern data of individual antennas in the set, and storing a propagation channel model representing amplitude and angle of arrival of one or more signal paths between a signal source and the mobile device;
computing a modified propagation channel model, comprising modifying at least the amplitude of the individual signal paths using the radiation pattern data and an angular orientation parameter that relates the radiation pattern data of individual antennas in the set to the angle of arrival of the respective signal paths; and
generating a test signal to emulate a wireless channel between the signal source and the mobile device using the modified propagation channel model.
18. The method of claim 17 , wherein the representative radiation pattern data for the antennas in the set is based on measured data of the antennas in the set.
19. The method of claim 17 , wherein the representative radiation pattern data for the antennas in the set is based on a representative model of the antennas in the set.
20. The method of claim 17 , wherein computing the modified propagation channel model further comprises modifying the phase of individual signal paths at the angle of arrival of said individual signal paths.
21. The method of claim 17 , wherein computing the modified propagation channel model further comprises modifying the signal paths to emulate spatial movement of the mobile device relative to the signal source.
22. The method of claim 21 , wherein modifying the signal paths to emulate spatial movement includes applying a Doppler spectrum based on a virtual spatial movement parameter that represents spatial movement of the mobile device relative to the signal source.
23. The method of claim 17 , wherein said conducting a test further comprises:
storing a second propagation channel model representing amplitude, phase, and angle of arrival of one or more second signal paths between a second signal source and the mobile device:
computing a second modified propagation channel model, comprising modifying at least the amplitude of individual second signal paths using radiation pattern data and a second angular orientation parameter; and
generating a second test signal to emulate a second wireless channel between the signal source and the mobile device using the second modified propagation channel model.
24. The method of claim 23 , wherein said conducting a test further comprises providing the second test signal to a signal feed to emulate handover of the mobile device between first and second base stations.
25. The method of claim 23 , wherein said conducting a test further comprises providing the second test signal to the signal feed to emulate an interference source.
26. The method of claim 23 , wherein said test signal and second test signal are provided for an overlapping period of time.
27. The method of claim 23 , further comprising coupling a test controller to the channel emulator and the mobile device, for controlling operation of channel emulator and the mobile device.
28. The method of claim 17 , wherein computing the modified propagation channel model includes modifying the signal paths to emulate proximity of the mobile device to external objects.
29. The method of claim 17 , wherein the representative radiation pattern data for the antennas in the set is based on measured data of the antennas in the set and includes proximity of the mobile device to external objects.
30. The method of claim 17 , wherein the amplitude and angle of arrival of the signal paths in the propagation channel model represent time-varying physical relationships between the signal source and the mobile device.
31. The method of claim 17 , wherein:
signal paths in the propagation channel model each comprise an associated plurality of signal sub-paths, the signal sub-paths representing sub-path amplitude, sub-path phase, and sub-path angle of arrival between the signal source and the mobile device; and
further comprising:
computing modified sub-path component values, comprising modifying at least the sub-path amplitude of individual signal sub-paths using the radiation pattern data and an angular parameter that related the radiation pattern data of individual antennas in the set to the angle of arrival of the respective sub-paths; and
summing the modified sub-path component values of the sub-paths associated with a given signal path to compute the signal paths in the modified propagation channel model.