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Metasurface‐programmable wireless on‐chip environment. a–c) Maps of the spatial field magnitude (for the field component that is perpendicular to the chip plane) along a horizontal slice inside the chip package shown in (d,e) with t = 100 µm for the indicated parameters (frequency and vertical height h). The colormap is linear. In addition, the transmitter (TX) and receiver (RX) locations considered in this paper are indicated in (a). d) Overview of the considered chip architecture. The chip is equipped with a 5 × 5 programmable metasurface in its ceiling. A part of the chip package is removed in this figure to show the interior. e) Vertical slice through the middle of the chip shown in (d), revealing the different layers and the programmable meta‐atoms. f) Detailed design of the considered programmable meta‐atom.
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This paper introduces the concept of smart radio environments, currently intensely studied for wireless communication in metasurface‐programmable meter‐scaled environments (e.g., inside rooms), on the chip scale. Wireless networks‐on‐chips (WNoCs) are a candidate technology to improve inter‐core communication on chips but current proposals are plag...
Citations
... EM waves can be regulated at will through the exquisite design of phase/amplitude distribution. Many previously inconceivable devices have been constructed in this way, such as metalens [26][27] , ultrathin cloak [28][29] , and on-chip metadevice [30][31][32][33] . Although most metasurfaces are still passive devices with xed functions, the lower pro le compared to bulky 3D metamaterials makes them much easier to regulate electrically. ...
Real-time dynamic super-resolution focusing technology is crucial for various applications, particularly in super-resolution imaging. However, the diffraction limit significantly impedes the achievement of real-time dynamic super-resolution imaging. Prior studies within this domain, such as super-resolution fluorescence imaging and structural illumination microscopy, heavily rely on fluorescent labels and intricate algorithms. This article proposes a novel approach to achieving real-time dynamic super-resolution imaging at microwave frequency by integrating the Mikaelian lens derived from conformal transformation optics with the space-time-coding metasurface antenna. Real-time dynamic super-resolution focusing with a resolution ranging from 0.3λ to 0.4λ is demonstrated at the periphery of the Mikaelian lens. The proposed hybrid lens exhibits the capacity to discern features separated by about one-third of a wavelength with high precision. Our work offers a universal solution for achieving dynamic real-time super-resolution imaging electrically, which can be extended to terahertz waves, visible light, and other wave fields, such as acoustic and flexural waves
... As for WiNoC inter-chip communication occurring in the THz range, the signals can suffer severe attenuation. As previously stated, IS are employed to shape channel impulse response at mmWave and THz frequencies [133,152]. With the detailed design of the on-chip IS, considering the impact of the thickness of the silicon layer over the signal attenuation and inter-symbol interference, the results have shown that IS can provide data transmission rates in on-off keying modulation with equalized wireless on-chip channels and double the permissible modulation speed for a given desired bit error rate value at a given noise level. ...
... The chip-scale communication also deserves special attention regarding further investigation of IS application. As pointed out in [133,152], it is possible to conduct a more in-depth analysis of intricate scenarios, such as the ones involving one transmitter and multiple receivers. The analysis of WiNoC can also be improved by incorporating different wave processing in scattering enclosures like matrix multiplication, signal differentiation, and reservoir computing [170][171][172]. ...
... The communication channels, including the IS-to-WiNoC, can also be better modeled to incorporate objects, such as racks, blades, chassis, and data centers [175,176]. Finally, other mmWave and THz ranges are worthy of exploration because they can enrich the present results of investigating IS-supported WiNoC using THz signals for communication, as there are still a few published results [133,152]. ...
Terahertz (THz) band will play an important role in enabling sixth generation (6G) envisioned applications. Compared with lower frequency signals, THz waves are severely attenuated by the atmosphere temperature, pressure, and humidity. Thus, designing a THz communication system must take into account how to circumvent or diminish those issues to achieve a sufficient quality of service. Different solutions are being analyzed: intelligent communication environments, ubiquitous artificial intelligence, extensive network automation, and dynamic spectrum access, among others. This survey focuses on the benefits of integrating intelligent surfaces (ISs) and THz communication systems by providing an overview of IS in wireless communications with the scanning of the recent developments, a description of the architecture, and an explanation of the operation. The survey also covers THz channel models, differentiating them based on deterministic and statistical channel modeling. The IS-aided THz channels are elucidated at the end of the survey. Finally, discussions and research directions are given to help enrich the IS field of research and guide the reader through open issues.
... In [14], authors developed the multi priority NoC (MP-NoC). These functions were referred to as address decoding, crossbar traversal, routing arbitration [15], and virtual channel allocation [16]. It is possible that the latency introduced by the router was the cause of the delay in the whole function. ...
... Figure 6 is a graphical representation of Table 2, which was shown in the figure that came before it. Table 3 presents a comparison of the performance of the proposed TCAM controller with that of many traditional methods, including RAM [13], CAM [15], and FIFO [16]. In this case, traditional memory controllers were not successful in optimizing the memory needs for the NoC, which led to an increase in the number of LUTs, LUT-FFs, and slice registers. ...
... Here, the proposed method consumed power as 1.065 watts. Figure 14 represents the proposed CDMA-NoC router-based throughput performance comparison with conventional approaches such as MP-NOC [15], MC-NOC [17], P-NOC [22], and FIFO-NoC [16] in 5G communication environment for 250 number of users. The proposed CDMA-NoC router resulted in 15 Mbps of data rates (throughput), whereas conventional proposed MP-NOC [15]routers resulted in 6.2 Mbps, MC-NOC [17], P-NOC [22] are resulted in 3.12 Mbps, and FIFO-NoC [16] resulted in 1.1 Mbpsat 240 number of users. ...
The 5G communications needs a high-speed data rate to satisfy the real-world communication applications. Further, the network on chip (NoC) plays the major role in real-time applications, which includes data communications, multi-processors and multi-controllers. However, existing NoC systems resulted in lower data rate with higher hardware resource utilization. Therefore, this article is focused on implementation of code division multiple access-NoC (CDMA-NoC router) using ternary content addressable memory (TCAM) buffer, Round Robin Arbiter (RRA) and XY-routing algorithm. Here, TCAM used to store the data generated across input and output ports. Further, TCAM also controls the read–write operations based on route requests. Then, RRA is used to allocate the priorities to the routes based on the traffic presented in the route. Finally, XY-routing algorithm transfers the data from source devices to destination devices through generated requests. Finally, the hardware-oriented simulations are conducted using Xilinx-ISE software platform and software-oriented simulations are conducted using Matlab-R2020a environment. The hardware-oriented simulations revealed that the proposed CDMA-NoC router resulted in superior area, delay, power performance as compared to state-of-art routers. The networking-oriented simulations also revealed that the proposed CDMA-NoC router resulted in superior networking performance in terms of data rates, energy efficiency, network capacity, and transmitted power for 250 number of users.
... All the energy propagating around the structure produces a multipath-rich environment that creates notches in the frequency response and lengthens the channel in time. The actual length of the channel depends mostly on the dimensions and resistivity of the silicon layer, which is a major contributor to the channel losses [33]. In any case, as we increase the symbol rate, the channel introduces significant ISI which undermines the quality of transmission [15]. ...
Wireless communications in the terahertz band have been recently proposed as complement to conventional wired interconnects within computing packages. Such environments are typically highly reverberant, hence showing long channel impulse responses and severely limiting the achievable rates. Fortunately, this communications scenario is static and can be pre-characterized, which opens the door to techniques such as time reversal. Time reversal acts a spatial matched filter and has a spatiotemporal focusing effect, which allows not only to increase the achievable symbol rates, but also to create multiple spatial channels. In this paper, the multi-user capability of time reversal is explored in the context of wireless communications in the terahertz band within a computing package. Full-wave simulations are carried out to validate the approach, whereas modulation streams are simulated to evaluate the error rate as a function of the transmitted power, symbol rate, and number of simultaneous transmissions.
... Thanks to the development of various multiple-scattering wave techniques such as time reversal of waves and wavefront/wavefield shaping [1][2][3][4] together with the hardware components, i.e., tunable lenses such as time-reversal mirrors [5][6][7], spatial wave modulators (SWMs) [8][9][10], and digital micromirror devices, it is now even possible to focus a wave through or inside a disordered, random medium [2,[11][12][13]. Such a breakthrough benefits a wide range of applications, e.g., energy storage and delivery [14][15][16][17], wireless communication [18][19][20][21], ultrasound sensing and imaging [22][23][24][25], reverberation control [10,26,27], and optical computing [28,29]. ...
Wavefronts modulated by a discrete-phase-sampling lens, such as a spatial light modulator or a digital micromirror device, can be brought into focus after propagating through a random medium. Such techniques are a cornerstone for wave manipulations in multiple scattering environments. In this work, we examine prevailing focusing protocols, including matched filtering and inverse filtering, from the perspective of focus quality, which is defined as the contrast between the energy delivered to the focal peak and the total transmitted energy. Our results show that conventional protocols have limitations in achieving the best focus quality. Based on these analyses, we present an improved wavefront-shaping protocol that directly prioritizes focus quality. The influence of phase sampling resolutions is also analyzed in conjunction with these focusing protocols. Our results can merit the future design and implementation of intelligent lenses, which may potentially benefit various disciplines such as energy delivery, imaging, and communication.
... The authors proved that self-adaptive RISs outperform context-ignorant RISs only below particular noise levels. In [148], initially, the authors designed and characterized a programmable metasurface for integration in the on-chip environment. Then the authors optimized the configuration to equalize selected wireless on-chip channels. ...
... Metasurface programmable wireless on-chip environment (images extracted from the work presented in[148]). ...
Recently reconfigurable intelligent surface (RIS) has attracted great attention because it can create a smart wireless environment. Hence it can enhance the capacity and coverage of the wireless network significantly. A thorough review of RISs has been presented in this paper focusing on the hardware aspect of the RIS. Beyond-5G/6G communication will have a smart propagation environment, where RIS can be used for such communications. RIS consists of various small unit cells. The unit cells should have some tunning mechanism so that the incoming waves can be reflected or transmitted in the desired direction. It is possible to tune the impedance of the unit cells using PIN diodes, varactor didoes, microelectromechanical (MEMS), thermal, and other ways. In this paper, initially, the background of RIS has been discussed where RIS is going to play a significant role in beyond-5G/6G communications. We have also added the theoretical background of RIS and motivations to writing this paper. After that several published papers in the literature have been presented so that the readers can get an overall idea about the RIS and its hardware. Hence, this paper will be very useful for practitioner engineers and researchers. RISs have been presented in various tables and various parameters have been presented. We have discussed challenges and solutions for the hardware of the RIS design. We have also discussed potential research and research gap that can be explored in the future. Lastly, we have added a conclusion for this review paper.
... Wireless Networks on-chip (WiNoCs) exploit, at the chip scale, the advantages of wireless communication, which offers the possibility of reducing the network topological constraints, of avoiding inter-router hops, and of reducing the latency [7][8][9]. Although the use of very high frequencies (e.g., in the THz range) allows one to reduce the size of the radiators [10,11], the on-chip integrability of miniaturized antennas still requires intensive technological research. ...
Optical Wireless Networks on-Chip are an emerging technology recently proposed to improve the interconnection between different processing units in densely integrated computing architectures. In this work, we propose a 4 × 4 optical wireless switch (OWS) based on optical phased arrays (OPAs) for broadband reconfigurable on-chip communication. The OPA and OWS design criteria are reported. Moreover, the performances of the OWS are analyzed and optimized considering the electromagnetic propagation in on-chip multilayer structures, with different thicknesses of the cladding layer. The effect on the OWS behavior of a non-ideal distribution of the power in input to the OPA is also investigated by designing a 1 × 7 beam splitter, based on a single-stage multi-mode interference (MMI) device to be used as a single element of the OWS. Then, the MMI output signals are considered in input to the transmitting OPAs and the OWS performances are evaluated.
... However, the performance of NoCs can quickly degrade when serving collective communication patterns such as reductions or broadcasts, especially when scaled. In light of this, WNoCs have been recently proposed to complement wired interconnects due to their natural broadcast support, low system-wide latency, and adaptive network topology [29], [32], [37], [38]. Even though WNoC technology is not mature, proof-of-concept designs have been implemented and tested [39]. ...
Hyperdimensional computing (HDC) is an emerging computing paradigm that represents, manipulates, and communicates data using long random vectors known as hypervectors. Among different hardware platforms capable of executing HDC algorithms, in-memory computing (IMC) has shown promise as it is very efficient in performing matrix-vector multiplications, which are common in the HDC algebra. Although HDC architectures based on IMC already exist, how to scale them remains a key challenge due to collective communication patterns that these architectures required and that traditional chip-scale networks were not designed for. To cope with this difficulty, we propose a scale-out HDC architecture called WHYPE, which uses wireless in-package communication technology to interconnect a large number of physically distributed IMC cores that either encode hypervectors or perform multiple similarity searches in parallel. In this context, the key enabler of WHYPE is the opportunistic use of the wireless network as a medium for over-the-air computation. WHYPE implements an optimized source coding that allows receivers to calculate the bit-wise majority of multiple hypervectors (a useful operation in HDC) being transmitted concurrently over the wireless channel. By doing so, we achieve a joint broadcast distribution and computation with a performance and efficiency unattainable with wired interconnects, which in turn enables massive parallelization of the architecture. Through evaluations at the on-chip network and complete architecture levels, we demonstrate that WHYPE can bundle and distribute hypervectors faster and more efficiently than a hypothetical wired implementation, and that it scales well to tens of receivers. We show that the average error rate of the majority computation is low, such that it has negligible impact on the accuracy of HDC classification tasks.
... For operation in quasi-free space with a blocked line-of-sight (LOS) between transmitter and receiver, RISs are mainly deployed as an alternative relaying mechanism [8], [15]- [17]. In rich-scattering environments [18], where multiple scattering yields a seemingly random superposition of reflected waves with all possible angles of arrival and polarizations, RISs are used to purposefully perturb the "disorder" to create a monochromatic [5], [19] or time-coherent polychromatic [20], [21] focus, for signal-to-noise (SNR) enhancement or over-theair equalization, respectively, as well as to optimize the rank of multiple-input multiple-output (MIMO) channels [22]. Besides these use cases in "active" communication, RISs are also used for encoding information into existing ambient waves in "passive" backscatter communication [23], [24]. ...
... Rigorous demonstrations of RIS-assisted over-the-air channel equalization were reported with experiments in the 2.5 GHz regime [20], and recently based on full-wave simulations in the context of WNoCs [21]. However, there is also a significant timely interest in studying these aspects based on channel models [56], [57]. ...
... To be clear, our contribution is not Algorithm 1 itself, which has already been used in Refs. [20], [21], but its implementation with our physically justified channel model, namely PhysFad. Algorithm 1 chooses the best out of 50 random RIS configurations and then tests element by element if flipping its state increases C. Multiple loops over all RIS elements are needed because the optimal configuration of a given RIS element depends on the configuration of all other RIS elements; this nonlinear RIS parametrization of the CIR can originate from various types of short-range and long-range correlations. ...
Programmable radio environments parametrized by reconfigurable intelligent surfaces (RISs) are emerging as a new wireless communications paradigm, but currently used channel models for the design and analysis of signal-processing algorithms cannot include fading in a manner that is faithful to the underlying wave physics. To overcome this roadblock, we introduce a physics-based end-to-end model of RIS-parametrized wireless channels with adjustable fading (coined PhysFad ) which is based on a first-principles coupled-dipole formalism. PhysFad naturally incorporates the notions of space and causality, dispersion (i.e., frequency selectivity) and the intertwinement of each RIS element’s phase and amplitude response, as well as any arising mutual coupling effects including long-range mesoscopic correlations. The latter are induced by reverberation and yield a highly nonlinear parametrization of wireless channels through RISs, a pivotal property which is to date completely overlooked. PhysFad offers the to-date missing tuning knob for physics-compliant adjustable fading. We thoroughly characterize PhysFad and demonstrate its capabilities for a prototypical problem of RIS-enabled over-the-air channel equalization in rich-scattering wireless communications. We also share a user-friendly version of our code to help the community transition towards physics-based models with adjustable fading.
... Among the key advantages of WNoCs, one can find a natural support to broadcast communications, reduced latency, and an adaptive network topology [36], [39], [48], [49]. Hence, WNoCs can be especially advantageous if they are used to serve specific communication patterns that are very challenging to tackle using conventional NoCs [46]. ...
