Xiaoye Shi^1,*, Fei Ding^1,2, Haiting Zhu¹, Zhaowei Zhang¹, Lei Zhang¹

CMC-Computers, Materials & Continua, Vol.74, No.3, pp. 4819-4830, 2023, DOI:10.32604/cmc.2023.018637

Abstract The simultaneous wireless information and power transfer (SWIPT) relay system is one of the emerging technologies. Xiaomi Corporation and Motorola Inc. recently launched indoor wireless power transfer equipment is one of the most promising applications. To tap the potential of the system, hybrid automatic repeat request (HARQ) is introduced into the SWIPT relay system. Firstly, the time slot structure of HARQ scheme based on full duplex two-way amplify and forward (AF) SWIPT relay is given, and its retransmission status is analyzed. Secondly, the equivalent signal-to-noise ratio and outage probability of various states are calculated by approximate simplification. Thirdly, the energy… More >

Raed Alhamad^*

Computer Systems Science and Engineering, Vol.43, No.2, pp. 751-765, 2022, DOI:10.32604/csse.2022.021932

Abstract In this article, we optimize harvesting and sensing duration for Cognitive Radio Networks (CRN) using Intelligent Reflecting Surfaces (IRS). The secondary source harvests energy using the received signal from node A. Then, it performs spectrum sensing to detect Primary Source P_S activity. When P_S activity is not detected, The Secondary Source S_S transmits data to Secondary Destination S_D where all reflected signals on IRS are in phase at S_D. We show that IRS offers 14, 20, 26, 32, 38, 44, 50 dB enhancement in throughput using M = 8, 16, 32, 64, 128, 256, 512 reflectors with respect to CRN without IRS. We… More >

Nasreen Anjum^1,*, Zhaohui Yang¹, Imran Khan², Mahreen Kiran³, Falin Wu⁴, Khaled Rabie⁵, Shikh Muhammad Bahaei¹

CMC-Computers, Materials & Continua, Vol.67, No.2, pp. 1759-1780, 2021, DOI:10.32604/cmc.2021.014635

Abstract In this paper, we propose a two-tiered segment-based Device-to-Device (S-D2D) caching approach to decrease the startup and playback delay experienced by Video-on-Demand (VoD) users in a cellular network. In the S-D2D caching approach cache space of each mobile device is divided into two cache-blocks. The first cache-block reserve for caching and delivering the beginning portion of the most popular video files and the second cache-block caches the latter portion of the requested video files ‘fully or partially’ depending on the users’ video watching behaviour and popularity of videos. In this approach before caching, video is divided and grouped in a… More >