Duty-Cycle-Based Pre-Emption Protocol for Emergency Networks

This paper proposes a new duty-cycle-based protocol for transmitting emergent data with high priority and low latency in a sensor network environment. To reduce power consumption, the duty cycle protocol is divided into a listen section and a sleep section, and data can only be received when the receiving node is in the listen section. In this paper, high-priority transmission preempts low-priority transmission by distinguishing between high-priority preamble and low-priority preamble. However, even when a high priority transmission preempts a low priority transmission such that the high priority transmission is received first, if the sleep period is very long, the delay may be large. To solve this problem, the high priority short preamble and high priority data reduce receiver sensitivity and increase coverage through repeated transmission. If there are several receiving nodes within a wide coverage, the receiving node that wakes up first can receive the transmission, thus reducing the delay. The delay can also be further reduced by alternately reducing the sleep cycle of one node among the receiving nodes that can receive it. This paper shows that emergent data can be transmitted effectively and reliably by reducing the delay of high-priority data to a minimum through the use of preemption, coverage extension, and an asymmetric sleep cycle.

Experimental Demonstration of High-Sensitivity Underwater Optical Wireless Communication Based on Photocounting Receiver

In this paper, we propose a high-sensitivity long-reach underwater optical wireless communication (UOWC) system with an Mbps-scale data rate. Using a commercial blue light-emitting diode (LED) source, a photon counting receiver, and return-to-zero on–off keying modulation, a receiver sensitivity of −70 dBm at 7% FEC limit is successfully achieved for a 5 Mbps intensity modulation direct detection UOWC system over 10 m underwater channel. For 1 Mbps and 2 Mbps data rates, the receiver sensitivity is enhanced to −76 dBm and −74 dBm, respectively. We further investigate the system performance under different water conditions: first type of seawater (c = 0.056 m−1), second type (c = 0.151 m−1), and third type (c = 0.398 m−1). The maximum distance of the 2 Mbps signal can be extended up to 100 m in the first type of seawater.

Robust and sparse Dual Tree Complex Wavelet Transform-based Twin Support Vector regression for dense 5G InH Communications

A robust and sparse Twin Support Vector Regression based on Dual Tree Discrete Wavelet Transform algorithm is conceived in this paper and applied to 28, 38, 60 and 73-GHz LOS (Line-of-Sight) wireless multipath transmission system in 5G Indoor Hotspot (InH) settings (simple, semi-complex and complex conference rooms) under small receiver sensitivity threshold. The algorithm establishes a denoising process in the learning phase based on Dual Tree Discrete Wavelet Transform (DT-CWT) which is suitable for time-series data. Additionally, the Close-In (CI) free space reference distance path loss model is analyzed and the large-scale propagation and probability distribution functions are investigated by determining the PLE (Path Loss Exponent) and the standard deviation of Shadow Factor (SF) for each InH scenario under consideration. Performance are evaluated under twelve (12) configuration scenarios, according to three criteria: mobility (0/3mps), receiver sensitivity threshold (-80/-120 dBm) and type of the InH area (simple, semi-complex and complex conference room). Experimental results confirm the effectiveness of the proposed approach compared to other standard techniques.

Spatial optical transceiver system–based key solution for high data rates in measured index multimode optical fibers for indoor applications

This study has simulated the spatial optical transceiver system based on measured index multimode optical plastic fibers channel with 1 Tb/s in 1.5 km distance. These plastic optical fibers are simply step index polycarbonate, step index polystyrene, step index polymethylmethacrylate, graded index polymethylmethacrylate and graded index cyclic transparent optical fiber (GI-CYTOP). Maximum Q-factor, optical signal power at optical fiber channel, receiver sensitivity, and coupling coefficient for sample of modes are measured based on GI-CYTOP fiber for the comparison between the previous model and the proposed model. This study clarified the enhancement of both maximum Q-factor and receiver sensitivity even though at high signal losses. The optimized Q-factor and receiver sensitivity are obtained for various plastic optical fiber channels. Power intensity level of dominant mode–based GI-CYTOP fiber channel is measured. The proposed model has presented better performance based on GI-CYTOP fiber channel in maximum Q-factor, which is within the percentage ratio ranging from 45.65 to 53.26%, optical signal power is within the percentage ratio ranging from 32.87 to 44.77%, and receiver sensitivity is within the percentage ratio ranging from 6.3 to 12.26% than the previous model at transmission distance ranges from 500 to 1500 m and bit rate of 2.5 Gb/s. GI-CYTOP fiber clarified better performance in maximum Q-factor and receiver sensitivity response better than other plastic optical fibers channels.