Addressing SDR Impairments for Wideband Channel Characterization using Multiband Splicing

Abstract:
Multiband splicing is a promising technique that enables wideband channel characterization using narrow-band devices. Instead of relying on high sampling rate, it leverages frequency hopping measurements across multiple narrow-bands to reconstruct a high-resolution channel impulse response (CIR). This approach is particularly appealing in the context of fragmented spectrum, especially in license-free bands, and benefits from the inherent advantages of narrow-band devices, such as lower cost and power consumption. However, a key technical challenge lies in correcting the phase distortions introduced by switching center frequencies, which is an essential step before accurate data concatenation. In this work, we investigate hardware impairments by implementing multiband splicing on software-defined radios, specifically USRP X410. We focus on analyzing the phase distortions encountered in overlapping frequency channels. Based on this analysis, we adapt targeted compensation methods from the literature, to mitigate these distortions and enable multiband splicing despite such hardware impairments. Our results show that the splicing-estimated channel impulse response (CIR) closely matches the reference wideband CIR, demonstrating the successful reconstruction of the channel.