TY - GEN
T1 - Channel Estimation with Simultaneous Reflecting and Sensing Reconfigurable Intelligent Metasurfaces
AU - Zhang, Haiyang
AU - Shlezinger, Nir
AU - Alamzadeh, Idban
AU - Alexandropoulos, George C.
AU - Imani, Mohammadreza F.
AU - Eldar, Yonina C.
N1 - Funding Information:
This work has been supported by the EU H2020 projects BNYQ under grant No. 646804 and RISE-6G under grant No. 101017011, as well as the Israel Science Foundation under grant No. 0100101.
Publisher Copyright:
© 2021 IEEE.
PY - 2021
Y1 - 2021
N2 - Reconfigurable Intelligent Surfaces (RISs) are envisioned to play a key role in future wireless communications, enabling programmable radio propagation environments. They are usually considered as nearly passive planar structures that operate as adjustable reflectors, giving rise to a multitude of implementation challenges, including an inherent difficulty in estimating the underlying wireless channels. In this paper, we propose the concept of Hybrid RISs (HRISs), which do not solely reflect the impinging waveform in a controllable fashion, but are also capable of sensing and processing a portion of it via some active reception elements. We first present implementation details for this novel metasurface architecture and propose a simple model for its operation, when considered for wireless communications. As an indicative application of HRISs, we formulate and solve the individual channels identification problem for the uplink of multi-user HRIS-empowered systems. Our numerical results showcase that, in the high signal-to-noise regime, HRISs enable individual channel estimation with notably reduced amounts of pilots, compared to those needed when using a purely reflective RIS that can only estimate the cascaded channel.
AB - Reconfigurable Intelligent Surfaces (RISs) are envisioned to play a key role in future wireless communications, enabling programmable radio propagation environments. They are usually considered as nearly passive planar structures that operate as adjustable reflectors, giving rise to a multitude of implementation challenges, including an inherent difficulty in estimating the underlying wireless channels. In this paper, we propose the concept of Hybrid RISs (HRISs), which do not solely reflect the impinging waveform in a controllable fashion, but are also capable of sensing and processing a portion of it via some active reception elements. We first present implementation details for this novel metasurface architecture and propose a simple model for its operation, when considered for wireless communications. As an indicative application of HRISs, we formulate and solve the individual channels identification problem for the uplink of multi-user HRIS-empowered systems. Our numerical results showcase that, in the high signal-to-noise regime, HRISs enable individual channel estimation with notably reduced amounts of pilots, compared to those needed when using a purely reflective RIS that can only estimate the cascaded channel.
KW - channel estimation
KW - metasurfaces
KW - Reconfigurable intelligent surfaces
KW - sensing
KW - smart radio environments
UR - http://www.scopus.com/inward/record.url?scp=85122829312&partnerID=8YFLogxK
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U2 - 10.1109/SPAWC51858.2021.9593172
DO - 10.1109/SPAWC51858.2021.9593172
M3 - Conference contribution
AN - SCOPUS:85122829312
T3 - IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC
SP - 536
EP - 540
BT - 2021 IEEE 22nd International Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2021
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 22nd IEEE International Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2021
Y2 - 27 September 2021 through 30 September 2021
ER -