Abstract
Channel emulators are the key instrument in radio performance testing. The fidelity of the
emulated channel with respect to the target channel models directly affects the credibility of the testing
result. In practice, due to some non-idealities of the radio-frequency (RF) components of the emulator,
its intrinsic frequency response, i.e., the response of the bypass mode, may not be flat over the frequency
band of interest, which leads to an excessive distortion over the target channel models, and hence a less
accurate emulated channel. This problem could be even more profound when the emulator engages the
band-stitching process for a wider-bandwidth emulation, especially in the transition frequency band between
adjacent sub-bands. To enable high-fidelity band-stitched or even ultra-wideband channel emulation, we
propose a novel digital pre-distortion concept in this work, where we pre-distort the target channel models
according to the measured intrinsic response of the emulator to compensate for its effect on the emulated
channel. The proposed method is numerically assessed with measured intrinsic responses of a commercial
emulator, and the magnitude and phase variations of the stitched channel reduce by one order of magnitude
in comparison to that of the conventional method.
emulated channel with respect to the target channel models directly affects the credibility of the testing
result. In practice, due to some non-idealities of the radio-frequency (RF) components of the emulator,
its intrinsic frequency response, i.e., the response of the bypass mode, may not be flat over the frequency
band of interest, which leads to an excessive distortion over the target channel models, and hence a less
accurate emulated channel. This problem could be even more profound when the emulator engages the
band-stitching process for a wider-bandwidth emulation, especially in the transition frequency band between
adjacent sub-bands. To enable high-fidelity band-stitched or even ultra-wideband channel emulation, we
propose a novel digital pre-distortion concept in this work, where we pre-distort the target channel models
according to the measured intrinsic response of the emulator to compensate for its effect on the emulated
channel. The proposed method is numerically assessed with measured intrinsic responses of a commercial
emulator, and the magnitude and phase variations of the stitched channel reduce by one order of magnitude
in comparison to that of the conventional method.
| Original language | English |
|---|---|
| Journal | IEEE Open Journal of Antennas and Propagation |
| Volume | 3 |
| Pages (from-to) | 932-939 |
| Number of pages | 8 |
| ISSN | 2637-6431 |
| DOIs | |
| Publication status | Published - 30 Jul 2022 |
Bibliographical note
This work was supported in part by the Innovation Fund Denmark under Project 1046-0006, and in part by the EURAMET European Partnership on Metrology Programme (MEWS) under the Framework of European COST INTERACT Action under Grant CA20120.Keywords
- Band-stitching
- Bandwidth
- Calibration
- Emulation
- Finite impulse response filters
- Frequency response
- Low-pass filters
- Radio frequency
- channel emulation
- digital pre-distortion
- equalization