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Wireless networking
Published in Matthew N. O. Sadiku, Optical and Wireless Communications, 2018
More than two dozen WLL technologies are on the market today, many offered by telecom companies. They can be divided into two categories: Wireless systems that use radio links for the fixed telephone services: CT2 (cordless telephone, generation 2), DECT (digital enhanced cordless telecommunications), and PHS (personal handyphone system) — CT2 and DECT are European standards, and PHS is a Japanese standard.Systems that use mobile cellular technology, such as DCS (digital communications services), derived from GSM and CDMA.
Introduction to Wireless Networking
Published in K.R. Rao, Zoran S. Bojkovic, Dragorad A. Milovanovic, Wireless Multimedia Communications, 2018
K.R. Rao, Zoran S. Bojkovic, Dragorad A. Milovanovic
ITU-DS is the UMTS frequency division duplex (FDD) standard; ITU-MC is CDMA-2000; and ITU-TC covers both UMTS time division duplex (TDD) and time division synchronous CDMA. The IMT-SC system, UWC-136, is the EDGE standard. The ITU-FT incorporates the European standard for cordless telephones—digital enhanced cordless telecommunications (DECT). DECT provides a local access solution which may be used, for example, in a home environment. The handset can automatically handover to a subscriber’s domestic access point, providing dedicated resources. Although the integration of DECT with GSM has been standardized, it has yet to see any exposure. The development of these standards is under the control of two partnership organizations formed from a number of regional standardization bodies. The 3GPP (Third Generation Partnership Project) is responsible for UMTS and EDGE, while the 3GPP2 (Third Generation Partnership Project 2) deals with CDMA2000 (Figure 1.9). DECT is the exception to this, with its standards developed solely by ETSI.31
Weak, Good, and Best Industry Practices
Published in Saad Z. Asif, 5G Mobile Communications Concepts and Technologies, 2018
Interference-Ridden Spectrum Block: State has the responsibility to provide a clean and interference-free spectrum. However, after the launch of 3G service, Zong found out that its 20–1930 MHz uplink band had heavy interference. This interference was due to the presence of DECT (Digital Enhanced Cordless Telecommunications) 6.0 cordless phones which were heavily present in the country. Primarily, these phones were smuggled into the country and no proper records were available with the authorities. Afterward, a campaign was jointly run by PTA and FAB to make the public aware of its illegal use and ask for their surrender. To compensate for this negligence, state temporarily provided 6.6 MHz in the 1800 MHz band to Zong, which was still with the operator until the time of writing of this case study (end of 2016).
Performance improvement of H-Shaped antenna with Zener diode for textile applications
Published in The Journal of The Textile Institute, 2022
Antennas are essential in communication since they enable electromagnetic waves to be transmitted and received in free space. A major problem in recent wireless applications is the construction of a powerful antenna with low-return loss and high gain. MSPA are popular because of their small size, ease of manufacture, basic construction, low cost, and omnidirectional radiation patterns. These characteristics give them a significant edge over conventional models. Cordless phones, near-field communication (NFC) applications, monitoring systems, and wireless computer networks may all be used for modern cell devices. The material's versatility is critical when designing antennas for these applications, especially for monitoring devices. As a result, lightweight materials such as cotton, felt, and Teflon may be used to create the MSP substrate sheet.
Multi-load constant current charging technology for wireless charging system
Published in International Journal of Electronics, 2020
Zhang Zhang, Zhou Xiaojuan, Xie Yulei, Xie Guangjun, Cheng Xin
With the extensive use of electronic products, the traditional way of using cables to provide energy for equipment has brought a lot of inconvenience and safety problems to people’s life. In contrast, wireless charging has the advantages of cordless and automatic charging. Therefore, building a wireless charging platform that can charge multiple devices simultaneously is attracting more and more attention. In practical applications, when there are multiple load devices, the mutual influence becomes uncertain as the relative position changes, and the charging current cannot be effectively controlled. Besides, the equivalent impedance of batteries that often used as energy storage devices is changing with the charging progresses, which makes the charging current unstable (Li, Li, Wang, Chen, & Yang, 2015). Therefore, for the multi-load wireless charging system, an independently adjustable control system should be separately designed on the primary and secondary side to cope with the change of the load.
Performance Evaluation of Co-Channel Interference on Wireless Networks
Published in Journal of Computer Information Systems, 2022
Joong-Lyul Lee, Joobum Kim, Myungjae Kwak
In recent years, numerous Internet of Things (IoT) devices are being used in our real life due to the development of wireless technology. For example, a smart light bulb, a smart home assistant, a smart wearable device, a smart door lock, a smart TV, a smart refrigerator, a smart vacuum cleaner, etc. are used in a smart home. These numerous IoT devices use the 2.4 GHz or 5 GHz frequency in which is an unlicensed Industrial, Scientific, and Medical (ISM) spectrum under the Federal Communications Commission (FCC). In addition, microwave ovens, cordless phones, Bluetooth devices, wireless security cameras, and ZigBee devices also used the ISM band. The IEEE 802.11 standard use in 2.4 GHz, 5 GHz, and 6 GHz frequency ranges. The Wireless LAN (WLAN) in the 2.4 GHz band provides 11 channels (1–11), each 20 MHz wide. Many of these devices cannot avoid the co-channel interference (CCI) phenomenon caused by using the same frequency and the adjacent channel interference (ACI) phenomenon caused by using adjacent frequencies. Even though it is recommended to use channels 1, 6, and 11 in order to avoid these channel interference phenomena, the interference phenomenon is inevitably experienced due to an increase in the number of IoT devices. Currently, new WLAN technology (IEEE 802.11 ac/ax) have been proposed to avoid these issues. However, this topic is still an ongoing issue as interference represents significant network performance degradation in WLAN, as many devices still use 2.4 GHz. Therefore, in this paper, we compare and analyze the CCI phenomenon with the simulation results in the ns-3 simulator and the real experiment results, and analyze how this phenomenon affects the network performance at the TCP layer.