The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this work, we implement and demonstrate differential amplify-and-forward (DAF) cooperative relaying as a novel diversity technique to combat bit errors and outages common in airborne environments. By using differential modulation and demodulation, we reduce the system complexity by avoiding channel estimation which is often unreliable or computationally costly in dynamic environments with mobile...
In helicopter satellite communications, the periodic blockage of the channel due to the rotor blades degrades the bit error rate (BER) performance. Although time diversity is attractive in order to overcome the periodic blockage, the combining process in the receiver requires the code synchronization. The pre-detection combining is suitable for time diversity because it is superior to the post-detection...
The Internet of Things (IoT), describing the Machine Type Communications (MTC), is in the center of many new technical studies and industrial projects. It is also a central topic for the future 5G technologies standardization. Pending the new generation of cellular networks, the 3rd Generation Partnership Project (3GPP) has already standardized in May 2016, an evolution of the 2G and 4G networks to...
In this paper, an enhanced scheme of Index Modulation for Orthogonal Frequency Division Multiplexing (IM-OFDM), called Repeated IM-OFDM with Diversity Reception (ReIM-OFDM) is proposed. ReIM-OFDM achieves performance improvement over the convetional IM-OFDM at the same spectral efficiency by providing additional space and frequency diversity. Similar to IM-OFDM, the proposed ReIM-OFDM also activates...
In this paper, the cellular mobile communication system with microdiversity and macrodiversity reception operating over Gamma shadowed Weibull multipath fading environment is analyzed. Macrodiversity selection combining (SC) receiver reduces Gamma long term fading effects and three microdiversity SC receivers mitigate Weibull short term fading effects on the system performance. The useful closed form...
In the growing context of Machine Type Communications (MTC), synthesized by the concept of Internet of Things (IoT), the need of an increased coverage pushes the industrial companies to develop efficient transmission techniques. Especially, the 3rd Generation Partnership Project (3GPP) already standardized evolutions of the 2G and 4G networks to include IoT features. These new standards share the...
RF energy harvesting (RFEH) is a promising technology for energy requirements of wireless communication nodes. However, providing sufficient amount of energy to ensure self-sufficient devices based on RFEH may be challenging. In this paper, the use of diversity combining in RFEH systems is proposed to increase the amount of harvested energy. The power consumption of diversity combining process is...
Receive diversity increases the reliability and robustness of ultra-low power Wireless Sensor Networks (WSNs) by using spatially separated antennas without modifying the physical layer. We consider a distributed ground network in the wild to track bats in their natural habitat. The bats are equipped with a sensor node of only 2 g that limits the energy budget available for communication. In this work,...
While buffer-aided relaying improves the diversity of a multi-hop network, its deployment introduces time-delays, thus rendering buffering unreliable for delay-intolerant applications. To alleviate excessive delays, various studies propose delayaware protocols, but at the expense of reduced diversity, and consequently, increased outage probability. Attempts to maintain the diversity of the system...
We evaluate the use of HARQ schemes in the context of vehicle to infrastructure communications considering ultra reliable communications in the short term from a channel capacity stand point. We show that it is not possible to meet strict latency requirements with very high reliability without some diversity strategy and propose a solution to determining an optimal limit on the maximum allowed number...
In this paper, a mixture gamma (MG) distribution that is highly accurate unified approximate approach is used to model the intractable statistical properties of α — κ — μ shadowed fading channels. The α — κ — μ shadowed fading channel contains the generalized α — κ — μ fading and gamma distribution which represent the impact of multipath fading and shadowing, respectively. The performance of communication...
Previous work has noted the distinct characteristics of vertically and horizontally polarized multipath components for indoor non-line-of-sight (NLOS) environments. Using measured data, the receiver signal-to-noise ratios (SNRs) for coherent and noncoherent combining of the co- and cross-polarized multipath components are compared to those obtained with omnidirectional reception for vertical or horizontal...
Antenna diversity has long been one method of increasing gains and enhancing performance in wireless systems. Such diversity provides a means to overcome the effects of signal multipath and fading in realistic RF channels or propagation environments. The design proposed here uses hybrid combining of two types of antenna diversity, spatial and polarization, to provide a consistently better received...
Multi-Carrier Code Division Multiple Access (MC-CDMA) is a novel approach for advanced wireless communication systems, since it has robustness against multipath fading channels. Due to asyncronous transmission among users Multiple Access Interference (MAI) has huge influence on the performance of MC-CDMA system. For supression of MAI, in this paper we have used MC-CDMA system along with the Orthogonal...
In this paper, a dual hop diversity communication system which is highly confidential for wireless applications is proposed to transmit the secret information from the source to receiver in the presence of interferences. In this proposed wireless communication system, the receiver is equipped with multiple antennas whereas the relays and interference are equipped with single antenna. The output signal...
Cooperative relays have been used in many wireless applications to reduce transmit power as well as adding receiver diversity. However, the energy efficiency trade-offs of relay networks have not been thoroughly investigated using a more complete energy model of the system. In this paper we present an energy model for a cooperative dual-relay system using decode-and-forward (DF) protocol with receiver...
This paper considers how selection techniques applied in an orthogonal frequency division multiplexing (OFDM)-based wireless local area network (WLAN) system influence on a system performance. Namely, ergodic and outage capacity of the considered system are simulated in order to determine the most adequate receiver design for certain WLAN environment.
A non-orthogonal multiple access (NOMA) technique is presented where the information bits of a user are carried by the least significant bits (LSBs) of other users' symbols. It is shown that the user performance can be improved by a receiver combining that relies on the alignment of sub-constellation corresponding to the LSBs at user receiver. The rate outage analysis shows that the proposed technique...
In this paper, we analyze and evaluate the performance of multibranch scan-and-wait combining (SWC) receivers over arbitrarily correlated and not necessarily identically distributed Nakagami-m fading channels. A fast convergent infinite series representation for the SWC output signal-noise ratio (SNR) is firstly presented. This expression is then used to obtain analytical expressions in the form of...
In this paper, wireless mobile macrodiversity (MaD) system with switch and stay (SSC) receiver and two dual branches microdiversity (MiD) selection combining (SC) structures operating over correlated Gamma shadowed Kappa-Mu (k-μ) multipath fading environment is taken into consideration. Cumulative distribution function (CDF) of MaD SSC receiver output signal is obtained and used for the evaluation...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.