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.
The Physical Layer Security (PLS) technology has been proved to be an effective way to reduce information leakage in wireless communication networks. This paper discusses the problem of secure transmission for Amplify-and-Forward (AF) cooperative network which contains both an external eavesdropper and some untrusted relays at the same time, where each relay acts as a helper of transmitting information...
The channels in a high-speed train (HST) environment are very quickly time-varying within an OFDM symbol so it is preferable to have their estimation and symbol detection to be simultaneously implemented. Time-varying characteristics of the channels also causes unavoidable inter-carrier interferences, which make both channel estimation and symbol detection doubly difficult. Considered in this paper...
The increasing demand for data and multimedia services, as well as the ubiquitous nature of the current generation of mobile devices have resulted in continuous network upgrades to support an ever-increasing number of users. However, given that wireless communication systems operate on radiofrequency waves, the health effects of electromagnetic (EM) emission from these systems are increasingly becoming...
The following paper investigates the secondary sum rate of MIMO two-way cognitive relay networks with multiple relays using amplify and forward (AF) strategy. The capacity of the system can be maximize by using optimum power allocation (OPA) algorithm in place of equal power allocation(EPA) among all nodes, while assuming that all node having fully channel state information (CSI). It has been considered...
In this study, optimal jamming of wireless localization systems is investigated. Two optimal power allocation schemes are proposed for jammer nodes in the presence of total and peak power constraints. In the first scheme, power is allocated to jammer nodes in order to maximize the average Cramér-Rao lower bound (CRLB) of target nodes whereas in the second scheme the power allocation is performed for...
Horizontal spectrum sharing occurs when multiple users share a given band of frequencies with no central control or coordination, and all users compete for access to the available spectrum. Depending on the actual approach used to allocate transmit power over available channels, mutual interference may affect user performance. Three types of horizontal spectrum sharing scenarios will be outlined in...
The ubiquity and convergence of wireless communication services have contributed to an unprecedented popularity of mobile communications. Given that wireless communication systems operate on radiofrequency waves, the electromagnetic (EM) radiation exposure they generate is also unprecedented and, hence, this could have adverse health effects on both humans and animals according to the World Health...
In order to fully exploit the high speed broadband multimedia services, prolonging the battery life of user equipment (UE) is critical from user's perspective, especially for the smartphone users. A collaborative mobile cloud (CMC), which consists of several UEs offers one potential solution for reducing the energy consumption at the terminal side. In this paper, an OFDMA mobile cloud system with...
In fading channels to get diversity gain, transmitted data can be repeated in time or frequency. Constellation reaarangement can be used instead of using the same signal constellation for each repeated transmission. In this method, symbols and the points in the signal space can be chosen differently for each one of the diversity branches. On the other hand, power allocation is another method that...
This paper proposes an optimal strategy for power allocation algorithm for source and relay nodes in multihop cognitive radio network that minimizes the outage probability of data transmission while meeting the constraints of interference to primary user and total transmit power of cognitive radio users. Overall objective is to enhance the network lifetime along with an increase in sum (total) transmission...
Bit and power allocation remains a challenge in multiuser multicarrier systems though optimal and suboptimal algorithms have been proposed. In this paper, we optimize the multiuser bit removal greedy algorithm by allowing removing bits in parallel, so reducing the computation time of the algorithm and making it attractive for real implementations. It has been proved that the proposed algorithm converges...
In cellular network, the deployment of the relay station can bring spatial diversity to increase link capacity and improve communication performance. In this paper, we consider an optimal power allocation scheme for the source and the relay to minimize the bit error rate (BER) at the destination under the power and outage constraint in cooperative relay system. Simulation results show that the BER...
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.