With the rapid requirement and development of the green ICT (Information and Communication Technology) technology, the demand for dynamically radio spectrum resources has significant attention. The low utilisation of licensed spectrum leads to the scarcity of the spectrum resource. The emerging cognitive radio (CR) systems become increasingly important in the wireless green communication. In co...

With recent advances in wireless technology, the importance of the capability to use multiple transmission rates and multiple radios has been widely recognized. In this paper, Multi-Rate and Multi-Radio (MR2) characteristics are exploited to improve end-to-end transmission delay for reliable multicasts. To achieve this goal, Maximum Potential Rate (MPR) based on multiple rates and Radio based T...

Cognitive Radio as a technological breakthrough and enabler for concepts such as Opportunistic Spectrum Access and Dynamic Spectrum Access has so far received significant attention from the research community from a theoretical standpoint. In this work, we build upon the theoretical foundation and present an implementation of a Software Defined Radio/Cognitive Radio platform, with the feature u...

802.11 WLANs suffer severe performance degradation as soon as at least one of the stations in the Basic Service Set (BSS) experiments unfavorable radio channel conditions. This degradation is due to a so-called anomaly which manifests when one or some of the stations adopt a reduced transmission data rate, as well as to the reduced efficiency of radio channel exploitation due to retransmissions...

This work proposes an easy-implement quadruple-frequency optical carrier suppression millimeter-wave (OCS-MMW) generation scheme for the generation and transmission of a 2.5 Gbps downlink data stream in a Radio over Fiber (RoF) system, based two commercially Dual-Drive Mach– Zehnder Modulator (DD-MZM). Theoretical analysis for back-to-back (B-T-B) transmission and optical fiber transmission is ...

Small cells are generally used by telecom operators to effectively share the loading of conventional macrocells and backbone networks, because they cost considerably less to deploy and are also capable of improving communication quality and capacity. However, radio frequency spectrum resources are limited and expensive, so using the same frequency band to deploy small cells in densely populated...

The current expansion of the Internet of things (IoT) demands improved communication platforms that support a wide area with low energy consumption. The 3rd Generation Partnership Project introduced narrowband IoT (NB-IoT) as IoT communication solutions. NB-IoT devices should be available for over 10 years without requiring a battery replacement. Thus, a low energy consumption is essential for ...

Radio-over-fiber (RoF) systems have been widely investigated due to such advantages of optical fiber as low loss, large bandwidth, and transparent characteristics for radio signal transmission. By utilizing RoF systems, various radio frequency (RF) signals including cellular services and wireless local area network (WLAN) signals can be efficiently distributed to densely populated areas or outd...

In cognitive radio networks (CRNs), the performance of the transmission control protocol (TCP) at the secondary user (SU) severely drops due to the mistrigger of congestion control. A long disruption is caused by the transmission of primary user, leading to the mistrigger. In this paper, we propose a cross-layer approach, called a CR-aware scheme that enhances TCP performance at the SU. The sch...