Saeed Ahmed Magsi^1,2,*, Mohd Haris Bin Md Khir¹, Illani Bt Mohd Nawi¹, Muath Al Hasan³, Zaka Ullah³, Fasih Ullah Khan⁴, Abdul Saboor⁵, Muhammad Aadil Siddiqui^1,2

CMC-Computers, Materials & Continua, Vol.75, No.1, pp. 845-862, 2023, DOI:10.32604/cmc.2023.033636

Abstract Long Range Wide Area Network (LoRaWAN) in the Internet of Things (IoT) domain has been the subject of interest for researchers. There is an increasing demand to localize these IoT devices using LoRaWAN due to the quickly growing number of IoT devices. LoRaWAN is well suited to support localization applications in IoTs due to its low power consumption and long range. Multiple approaches have been proposed to solve the localization problem using LoRaWAN. The Expected Signal Power (ESP) based trilateration algorithm has the significant potential for localization because ESP can identify the signal’s energy below the noise floor with no… More >

Yun Fen Yong^1,*, Chee Keong Tan¹, Ian Kim Teck Tan², Su Wei Tan¹

CMC-Computers, Materials & Continua, Vol.74, No.1, pp. 1801-1818, 2023, DOI:10.32604/cmc.2023.032710

Abstract A robust radio map is essential in implementing a fingerprint-based indoor positioning system (IPS). However, the offline site survey to manually construct the radio map is time-consuming and labour-intensive. Various interpolation techniques have been proposed to infer the virtual fingerprints to reduce the time and effort required for offline site surveys. This paper presents a novel fingerprint interpolator using a multi-path loss model (M-PLM) to create the virtual fingerprints from the collected sample data based on different signal paths from different access points (APs). Based on the historical signal data, the poor signal paths are identified using their standard deviations.… More >

Md Abdus Samad^1,2, Dong-You Choi^1,*

CMC-Computers, Materials & Continua, Vol.71, No.2, pp. 3127-3143, 2022, DOI:10.32604/cmc.2022.023086

Abstract In present-day society, train tunnels are extensively used as a means of transportation. Therefore, to ensure safety, streamlined train operations, and uninterrupted internet access inside train tunnels, reliable wave propagation modeling is required. We have experimented and measured wave propagation models in a 1674 m long straight train tunnel in South Korea. The measured path loss and the received signal strength were modeled with the Close-In (CI), Floating intercept (FI), CI model with a frequency-weighted path loss exponent (CIF), and alpha-beta-gamma (ABG) models, where the model parameters were determined using minimum mean square error (MMSE) methods. The measured and the… More >

Abhinav Adarsh¹, Basant Kumar¹, Manoj Gupta², Arun Kumar², Aman Singh^3,*, Mehedi Masud⁴, Fahad A. Alraddady⁵

CMC-Computers, Materials & Continua, Vol.69, No.1, pp. 35-49, 2021, DOI:10.32604/cmc.2021.017647

Abstract This paper presents a new low delay centralized cooperative spectrum sensing method based on dynamic voting rule using multiple threshold level, for indoor hospital environment, where fading and direct path loss both are together responsible for variation in signal strength. In the proposed algorithm, weights of Cognitive Radios (CRs) in terms of assigned vote-count are estimated based on the sensed energy values with respect to multiple fixed threshold levels, so that the direct path loss can be dealt without further increasing the error, which occurs due to fading. For indoor hospital like environment, Rician fading model is more appropriate. Therefore,… More >

Faizan Qamar¹, Mhd Nour Hindia², Tharek Abd Rahman³, Rosilah Hassan¹, Kaharudin Dimyati², Quang Ngoc Nguyen^4,*

CMC-Computers, Materials & Continua, Vol.68, No.2, pp. 2249-2264, 2021, DOI:10.32604/cmc.2021.017198

Abstract The 5G network has been intensively investigated to realize the ongoing early deployment stage as an effort to match the exponential growth of the number of connected users and their increasing demands for high throughput, bandwidth with Quality of Service (QoS), and low latency. Given that most of the spectrums below 6 GHz are nearly used up, it is not feasible to employ the traditional spectrum, which is currently in use. Therefore, a promising and highly feasible effort to satisfy this insufficient frequency spectrum is to acquire new frequency bands for next-generation mobile communications. Toward this end, the primary effort… More >

Huarui Wu^1,2,3, Huaji Zhu^1,2,3, Xiao Han^1,2,3,*, Wei Xu⁴

Computer Systems Science and Engineering, Vol.37, No.1, pp. 89-104, 2021, DOI:10.32604/csse.2021.015030

Abstract When wireless sensor networks (WSN) are deployed in the vegetable greenhouse with dynamic connectivity and interference environment, it is necessary to increase the node transmit power to ensure the communication quality, which leads to serious network interference. To offset the negative impact, the transmit power of other nodes must also be increased. The result is that the network becomes worse and worse, and node energy is wasted a lot. Taking into account the irregular connection range in the cucumber greenhouse WSN, we measured the transmission characteristics of wireless signals under the 2.4 Ghz operating frequency. For improving network layout in… More >