More Like this

1. Magnitude-Phase Optical OFDM for IM/DD Communication Systems

   https://doi.org/10.1109/ACSSC.2018.8645420  

   Lian, Jie; Brandt-Pearce, Maite (October 2018, 52nd Asilomar Conference on Signals, Systems, and Computers)

   Orthogonal frequency division multiplexing (OFDM) is a candidate technique to provide high-speed data transmissions for optical communication systems. For intensity modulation and direct detection (IM/DD) optical communication systems, only real and non-negative valued signals can be transmitted due to the natural properties of the transmitters and receivers. This paper proposes a technique called magnitude-phase optical OFDM (MPO-OFDM) that transmits the magnitude and phase of the conventional complex valued OFDM signal successively, similar to polar-based OFDM. Unlike polar-based OFDM, however, the proposed MPO-OFDM quantizes, encodes, and transmits the phase information using pulse amplitude modulation (PAM) to reduce the interference introduced by the additive noise on the phase. Considering the peak radiation power constraint of optical devices, the magnitude component of the MPO-OFDM signal experiences clipping distortion. In this paper, we optimally adjust the modulation index to control the scale of the magnitude component and achieve the highest signal to noise ratio (SNR). For the same transmitted data rate, the proposed MPO-OFDM can achieve a lower bit error rate than previously proposed techniques. For a similar BER performance, MPO-OFDM can support a higher throughput than the other techniques tested. 

   more » « less
2. NetHD: Neurally Inspired Integration of Communication and Learning in Hyperspace

   https://doi.org/10.1002/aisy.202300841  

   Poduval, Prathyush P; Ni, Yang; Zou, Zhuowen; Ni, Kai; Imani, Mohsen (July 2024, Advanced Intelligent Systems)

   The 6G network, the next‐generation communication system, is envisaged to provide unprecedented experience through hyperconnectivity involving everything. The communication should hold artificial intelligence‐centric network infrastructures as interconnecting a swarm of machines. However, existing network systems use orthogonal modulation and costly error correction code; they are very sensitive to noise and rely on many processing layers. These schemes impose significant overhead on low‐power internet of things devices connected to noisy networks. Herein, a hyperdimensional network‐based system, called , is proposed, which enables robust and efficient data communication/learning. exploits a redundant and holographic representation of hyperdimensional computing (HDC) to design highly robust data modulation, enabling two functionalities on transmitted data: 1) an iterative decoding method that translates the vector back to the original data without error correction mechanisms, or 2) a native hyperdimensional learning technique on transmitted data with no need for costly data decoding. A hardware accelerator that supports both data decoding and hyperdimensional learning using a unified accelerator is also developed. The evaluation shows that provides a bit error rate comparable to that of state‐of‐the‐art modulation schemes while achieving 9.4 faster and 27.8 higher energy efficiency compared to state‐of‐the‐art deep learning systems. 

   more » « less
3. Optical Focusing-Based Adaptive Modulation for Air-to-Underwater Optoacoustic Communication

   https://doi.org/10.1109/JSEN.2023.3340092  

   Mahmud, Muntasir; Younis, Mohamed; Choa, Fow-Sen; Ahmed, Akram (March 2024, IEEE Sensors Journal)

   Nonlinear optoacoustics enable effective communication across the air-water interface. However, the requirement of a high-power laser and the vapor cloud buildup can limit the power efficiency and data rate. Thus, a proper modulation and encoding scheme is necessary. This article tackles this issue by presenting an optical focusing-based adaptive modulation (OFAM) technique that can dynamically control the underwater acoustic source (plasma) and acoustic pressure. Specifically, the article describes two variants of OFAM for a single laser transmitter with stationary focusing (OFAM-1D) and dynamic focusing (OFAM-3D). The data rate of OFAM-1D and OFAM-3D is approximately 6 and 4.4 times higher than peak detection based on-off keying (PDOOK). Furthermore, both techniques are 137% more power efficient than PDOOK. Studying the bit error rate (BER) in the presence of ambient underwater noises for different node positions has indicated that OFAM can achieve low BER even at a 300-m depth for 50- and 60-mJ laser pulse energy. Moreover, machine learning (ML) techniques have been leveraged in the demodulation process for increased robustness. Specifically, the random forest (RF) model could yield up to 94.75% demodulation accuracy. Our results indicate that OFAM can lead to a new paradigm of air to underwater wireless communication. 

   more » « less
4. Mixed-Carrier Communication for Technology Division Multiplexing

   https://doi.org/10.3390/electronics10182248  

   Hussein, Ahmed F.; Saha, Dola; Elgala, Hany (September 2021, Electronics)

   null (Ed.)

   Recently, research on sixth-generation (6G) networks has gained significant interest. 6G is expected to enable a wide-range of applications that fifth-generation (5G) networks will not be able to serve reliably, such as tactile Internet. Additionally, 6G is expected to offer Terabits per second (Tbps) data rates, 10 times lower latency, and near 100% coverage, compared to 5G. Thus, 6G is expected to expand across all available spectrums including terahertz (THz) and optical frequency bands. In this manuscript, mixed-carrier communication (MCC) is investigated as a novel physical layer (PHY) design for 6G networks. The proposed MCC version in this study is based on visible light communication (VLC). MCC enables a unified transmission PHY design to connect devices with different complexities, simultaneously. The design trade-offs and the required signal-to-noise ratio (SNR) per individual modulation schemes embedded within MCC are investigated. The complexity analysis shows that a conventional optical OFDM receiver can capture the high-speed bit-stream embedded within MCC. For a forward error correction (FEC) bit-error-rate (BER) threshold of 3.8×10−3, MCC is optimized to maximize the spectral efficiency by embedding 2-beacon phase-shift keying (2-BnPSK) within an MCC envelope on top of 12 bits per beacon position modulation (BPM) symbol. 

   more » « less
5. Miniaturized PMUT-based receiver for underwater acoustic networking

   Herrera, B; Pop, F; Rinaldi, M; Cassella, C (September 2020, Microelectromechanical systems)

   The present work reports on the novel implementation of a miniaturized receiver for underwater networking merging a Piezoelectric Micromachined Ultrasonic Transducer (PMUT) array and signal conditioning circuitry in a single, packaged device. Tests in both a large water tank and a pool demonstrated that the system can attain large enough Signal-to-Noise Ratio (SNR) for communication at distances beyond two meters. An actual communication test, implementing an Orthogonal Frequency Division Multiplexing (OFDM) scheme, was used to characterize the performance of the link in terms of Bit Error Rate (BER) vs SNR. In comparison to previous work demonstrating high-data rate communication for intra-body links and acoustic duplexing, this implementation allows for significantly larger distances of transmission, while addressing the signal conditioning and submersible packaging needs for underwater conditions, thus enabling PMUT arrays for operating as complete underwater communication receivers. 

   more » « less