We demonstrate a far-UVC optical wireless communication system employing $\mu$ LED transmitters emitting at 235 nm. Reducing the device dimensions to the micro-metre regime decreases the active area, enabling higher current densities and lower junction capacitance, which together enhance the modulation bandwidth relative to conventional large-area AIGaN LEDs. The resulting improvement in high-speed performance allows the intrinsic bandwidth limitations of deep-ultraviolet emitters to be mitigated. Using these $\mu$ LEDs in a short-range free-space link, data rates of up to 1.5 Gbps are achieved. These results highlight the potential of far-UVC $\mu$ LED technology for compact, solarblind optical wireless communication systems requiring high data throughput.
This paper presents a novel architecture for realizing a fully parallel and flexible digital baseband processor for massive MIMO systems using processing-in-memory (PIM). The proposed approach leverages memristor-based crossbar arrays to implement key functional blocks within the baseband processing chain, thereby alleviating the data-movement bottleneck inherent in conventional von Neumann architectures. To enable efficient hardware mapping, the signal processing algorithms and corresponding computations are reformulated into a unified matrixbased framework. The resulting matrix operations are then mapped onto multiple crossbar arrays, exploiting their intrinsic analog computing capabilities. The proposed PIM-based baseband processor achieves fully parallel operation and significantly reduces processing latency, making it well suited to the stringent performance requirements of next-generation wireless systems. The presented architecture demonstrates the potential of PIM technology as an effective solution for future high-performance and energy-efficient baseband processing platforms.
This paper evaluates the performance of different multi-point transmission schemes in a software-defined multi-cell Visible Light Communication (VLC) system. Using a GNU Radio and Universal Software Radio Peripheral (USRP)-based testbed with phosphor-converted white LEDs and black silicon photodetectors, we assess the achievable data rates for Zero-Forcing (ZF) precoding and Joint Transmission (JT) scheme in a distributed Multiple-Input Multiple-Output (MIMO) VLC configuration. OFDM waveforms are utilized and co-channel interference is modeled as additive white Gaussian noise. Experimental results show that the data rate performance is mainly limited by the narrow electrical modulation bandwidth of phosphor-converted LEDs, yielding a $150-160 ~\text{cm}$ single-cell coverage radius. In a two-cell scenario with an LED separation of 170 cm, ZF, JT, and Single-Input Single-Output (SISO) are the most convenient scheme for 46%, 32%, and 22% of the service area, respectively.
Using 3D scanning radars is essential for aircraft. MIMO radars significantly simplify their installation in aircraft while significantly increasing equivalent resolution. However, implementing MIMO elements in wings poses a significant challenge due to their deflection, which degrades the radar images or makes it unusable. The objective of our study was to research and develop a method for configuring 3D imaging MIMO radars in the wings of various aircraft, taking into account arbitrary deflections. We examined radar images obtained by radar due to arbitrary deflections of aeroplane wings. Deflection includes both static and dynamic effects, particularly flutter. A mathematical model of a radar installed in deformable wings has been developed. We propose a method for compensating the MIMO model calculation for deflections, which restores the original radar image. We provide a calculation of the accuracy of the method depending on the accuracy of the sensors. We demonstrate that using simple sensors that measure arbitrary wing deflection, high-quality radio imaging can be obtained using MIMO radar. The proposed method is invariant to both the radar frequency range and the aircraft size.
A realistic indoor office in Oxford is modeled to examine channel propagation based on visible light communications (VLC), employing light-emitting diodes as optical luminaires. A design tool for optical systems, called Zemax, is used to model the indoor office room. Moreover, ray tracing in Zemax is accounted for two comparative VLC propagation scenarios. Further, channel impulse response and channel frequency response metrics are emphasized. Building upon these propagation metrics, ultimately, the 3 dB channel bandwidth versus receiver position results are investigated for an indoor office room, accounting for the considered comparative propagation scenarios. Concerning the key findings of scenario 1, 50 MHz and 150 MHz 3 dB channel bandwidths are obtained at the center and at the corners, respectively. Likewise, for scenario 2, 40 MHz and 50 MHz 3 dB channel bandwidths are obtained at the center and at the corners, respectively.
