More Like this

1. An Adaptive DPPM for Efficient and Robust Visible Light Communication Across the Air-Water Interface

   https://doi.org/10.1109/WOCC48579.2020.9114944  

   Islam, Md Shafiqul ; Younis, Mohamed ( May 2020 , 2020 29th Wireless and Optical Communications Conference (WOCC))

   The scarcity of the optical power is the main challenge for underwater visible light communication. It becomes worst for communication across the air-water interface because of the reflection of light from the air-water interface. Differential pulse position modulation (DPPM) is one of the power efficient modulation techniques. In L-DPPM a block of M = log 2 L input data is mapped into one of the L distinct waveforms containing only one 'on' chip. The size of the DPPM packet is variable and depends on the value of input data and L, which makes error detection quite challenging. In this paper, we propose a frame structure that efficiently enables error detection within a packet for various symbol length, L, of DPPM. We also propose an algorithm using such a frame structure to enable effective detection of packet errors and for adaptively changing the value of L for optimal power efficiency while meeting a certain bound on the packet error rate (PER). We have named our proposed protocol as adaptive differential pulse position modulation (ADPPM). The Bit rate and PER have been studied for different signal-to-noise ratio (SNR) through simulation. A comparison between ADPPM and OOK, DPPM with fixed L is provided. 

   more » « less
2. Enabling Underwater Acoustic Cooperative MIMO Systems by Metamaterial-Enhanced Magnetic Induction

   Desai, Soham ; Sudev, Vaishnendr ; Tan, Xin ; Wang, Pu ; Sun, Zhi ( April 2019 , 2019 IEEE Wireless Communications and Networking Conference (WCNC))

   The acoustic cooperative multi-input-multi-output (MIMO) systems equipped on the underwater robot swarms (URSs) can enable long-range and high-throughput communications. However, the acoustic communications cannot provide the real-time and accurate synchronization for the distributed transmitters of the cooperative MIMO due to the large delay of acoustic channels. In addition, the narrow bandwidth of the acoustic channel further enlarges the synchronization time and errors. In this paper, we propose the metamaterial magnetic induction (M2I)-assisted acoustic cooperative MIMO to address aforementioned challenges. The synchronization time can be reduced since the M2I has negligible signal propagation delays. To quantitatively analyze the improvement, we deduce the synchronization errors, signal-to-noise ratio (SNR), eective communication time, and the throughput of the system. Finally, the improvement of using M2I-assisted synchronization is validated by the numerical evaluation. 

   more » « less
3. Fusion Learning on Multiple-Tag RFID Measurements for Respiratory Rate Monitoring

   https://doi.org/10.1109/BIBE50027.2020.00082  

   Hansen, Stephen ; Schwartz, Daniel ; Stover, Jesse ; Tajin, Md Abu ; Mongan, William M. ; Dandekar, Kapil R. ( October 2020 , 2020 IEEE 20th International Conference on Bioinformatics and Bioengineering (BIBE))

   null (Ed.)

   Future advances in the medical Internet of Things (IoT) will require sensors that are unobtrusive and passively powered. With the use of wireless, wearable, and passive knitted smart garment sensors, we monitor infant respiratory activity. We improve the utility of multi-tag Radio Frequency Identification (RFID) measurements via fusion learning across various features from multiple tags to determine the magnitude and temporal information of the artifacts. In this paper, we develop an algorithm that classifies and separates respiratory activity via a Regime Hidden Markov Model compounded with higher-order features of Minkowski and Mahalanobis distances. Our algorithm improves respiratory rate detection by increasing the Signal to Noise Ratio (SNR) on average from 17.12 dB to 34.74 dB. The effectiveness of our algorithm in increasing SNR shows that higher-order features can improve signal strength detection in RFID systems. Our algorithm can be extended to include more feature sources and can be used in a variety of machine learning algorithms for respiratory data classification, and other applications. Further work on the algorithm will include accurate parameterization of the algorithm's window size. 

   more » « less
4. A 41.5 pJ/b, 2.4GHz Digital-Friendly Orthogonally Tunable Transceiver SoC with 3-decades of Energy-Performance Scalability

   https://doi.org/10.1109/CICC48029.2020.9075915  

   Chatterjee, Baibhab ; Sen, Shreyas ( April 2020 , IEEE Custom Integrated Circuits Conference (CICC))

   null (Ed.)

   Adaptive communication for Internet of Things (IoT) and Wireless Body Area Network (WBAN) technologies is becoming increasingly popular due to the large power-performance trade-offs and highly dynamic channel conditions. Path loss, low signal to noise ratio (SNR) in the channel and network congestion adversely affect the data communication, each of which can be taken care of using different strategies such as reducing the data rate (for reducing congestion), increasing the output power (for increased path loss) and application of error correction coding (ECC, for low SNR). In this paper, we present a digital-friendly Transceiver SoC consisting of an RF-DAC based transmitter with orthogonally tunable output power, data rate and ECC that enables optimum system level bit error rate (BER) and energy for over 3-orders of energy-performance scalability, along with an ultra-low-power OOK receiver that receives the transmitter's control bits from a nearby base station for closed-loop control. The data rate and ECC control is achieved through a digital baseband, while a tapped capacitor matching network controls the output power. The energy efficiency of the transmitter is 27.6pJ/b at 10MSps and at 0.8V supply (~9X improvement over state-of-the-art), while the entire SoC (Transmitter+OOK receiver for controller feedback) consumes only 41.5pJ/b. 

   more » « less
5. Impact of blockers on user equipment angular diversity in THz Microcellular scenarios

   Gomez-Ponce, Jorge ; Abbasi, Naveed ; Abu-Surra, Shadi ; Xu, Gary ; Zhang, Charlie ; Molisch, Andreas F. ( May 2023 , IEEE International Conference on Communications)

   The availability of large bandwidths in the terahertz (THz) band will be a crucial enabler of high data rate applications in next-generation wireless communication systems. The urban microcellular scenario is an essential deployment scenario where the base station (BS) is significantly higher than the user equipment (UE). Under practical operating conditions, moving objects (i.e., blockers) can intermittently obstruct various parts of the BSUE link. Therefore, in the current paper, we analyze the effect of such blockers. We assume a blockage of the strongest beam pair and investigate the availability and extent of angular diversity, i.e., alternative beampairs that can sustain communication when the strongest is blocked. The analysis uses double-directional channel measurements in urban microcellular scenarios for 145- 146 GHz with BS-UE distances between 18 to 83 m. We relate the communication-system quantities of beam diversity and capacity to the wireless propagation conditions. We show that the SNR loss due to blockage depends on the blocked angular range and the specific location, and we find mean blockage loss to be on the order of 10-20 dB in line-of-sight (LOS) and 5-12 dB in NLOS (non-LOS). This analysis can contribute to the design of intelligent algorithms or devices (e.g., beamforming, intelligent reflective surfaces) to overcome the impact of the blockage. 

   more » « less