Serwis Infona wykorzystuje pliki cookies (ciasteczka). Są to wartości tekstowe, zapamiętywane przez przeglądarkę na urządzeniu użytkownika. Nasz serwis ma dostęp do tych wartości oraz wykorzystuje je do zapamiętania danych dotyczących użytkownika, takich jak np. ustawienia (typu widok ekranu, wybór języka interfejsu), zapamiętanie zalogowania. Korzystanie z serwisu Infona oznacza zgodę na zapis informacji i ich wykorzystanie dla celów korzytania z serwisu. Więcej informacji można znaleźć w Polityce prywatności oraz Regulaminie serwisu. Zamknięcie tego okienka potwierdza zapoznanie się z informacją o plikach cookies, akceptację polityki prywatności i regulaminu oraz sposobu wykorzystywania plików cookies w serwisie. Możesz zmienić ustawienia obsługi cookies w swojej przeglądarce.
Dynamic spectrum access (DSA) is an important design aspect for the cognitive radio networks. Most of the existing DSA schemes are to govern the unlicensed user (i.e., secondary user) traffic in a licensed spectrum without compromising the transmissions of the licensed users, in which all the unlicensed users are typically treated equally. In this paper, prioritized unlicensed user traffic is considered...
In this paper we analyze mechanisms of coexistence between different cognitive radio systems operating as secondary users in white space frequency bands. In particular, our focus is coexistence mechanisms that can be provided by IEEE 802.19.1 coexistence system. IEEE 802.19.1 standard is at the early stage of its development. At this stage it is very important to consider different design directions...
A new censoring cooperative spectrum sensing scheme in cognitive radio (CR) network is proposed in this paper, which is based on stochastic resonance (SR) technique and optimal censoring interval. The selection strategy for the optimal censoring interval is derived. The observations of the cooperative secondary users (SUs) whose statistics fall into the censoring interval are processed by SR system...
Incentive protocols are crucial for enhancing contribution and cooperation among nodes in P2P networks. In this paper, we consider an analytical framework wherein peers learn the gains of different strategies and evolve adaptively towards the better performance strategy. While a unitary incentive policy in the system may exhibit its incentive capability on itself, the competition among different incentive...
Compared with the conventional one-way counterpart, two-way cooperative communications can significantly improve spectrum efficiency. When no channel state information is available at the receivers, we propose optimal non-coherent detector based on maximum likelihood rule for frequency-shift keying modulated two-way amplify-and-forward (AF) cooperative communications in Rayleigh fading channels. We...
It has been well recognized that channel state information (CSI) feedback is important for dowlink transmissions of closed-loop wireless networks. In this paper, we investigate the CSI feedback rate control problem in the analytical setting of a game theoretic framework, where a multiple-antenna base station (BS) communicates with a number of co-channel mobile stations (MS) through a minimum mean...
Due to the massive use of parallel and distributed operations of inputs and outputs, iterative scheduling algorithms are attractive in finding a maximal size matching for an input-queued switch. For constructing a large high-speed switch, a distributed multi-chip implementation of an iterative scheduling algorithm should be followed. Since different chips may locate on different switch linecards and...
Femtocells have been considered by the wireless industry as a promising solution not only to improve indoor coverage, but also to unload traffic from already overburdened macrocells. In spite of potentially excessive interference caused by densely deployed femtocells, macrocells may have to share the same spectrum with femtocells, due to spectrum availability and network infrastructure considerations...
IEEE 802.11ac is enhancing the throughput beyond IEEE 802.11n using the 80 MHz channel bonding technique. In this paper, we first overview the static 40 MHz and the dynamic 20/40 MHz bandwidth channel access schemes defined in 802.11n. We then extend the schemes to the IEEE 802.11ac for the 80 MHz wide channel and study the static and dynamic channel access schemes. The simulation results show that...
Lagrange dual optimization technique (LDO) is a powerful tool for solving constrained optimization problems in multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing systems (OFDM) and is generally considered to be optimal in the literature. LDO relaxes a constrained problem into an unconstrained dual problem using Lagrange multipliers. To solve the dual problem, the optimal...
How to design the next-generation Internet is an open technique issue. One of the mainstream ideas is to enhance network routers with application-oriented intelligence. For example, firewalls,Web proxies/caches, mobile gateways, and multicast capable nodes are equipments with application-oriented intelligence for security/performance enhancement. However, there is no systematic study on what intelligence...
Recently, cognitive radio has become a hot spot, in which secondary users could use the frequency bands when primary users are absent. Hence, the detection of primary users' presence plays an important role in cognitive radio networks. In this paper, a cognitive radio network with multiple licensed users is considered. Secondary users cooperatively detect the presence of primary users using energy...
Compressed sensing is an emerging theory which provides a new framework for sampling and compressing a sparse signal simultaneously at a reduced sampling rate. Besides this, compressed sensing also provides a new approach for the task of detection. Detection from compressive measurements without reconstructing the signals remains as a challenging problem. In this paper, we investigate the performance...
Fractional frequency reuse (FFR) is an efficient method to suppress inter-cell interference (ICI) in multi-cell OFDMA networks. In this paper, the optimal threshold is designed for FFR schemes to identify cell central and edge users. We first derive throughput of the FFR scheme considering small-scale fading channels and different scheduling strategies. Then we conclude from the analysis and simulation...
BitTorrent has been a very successful peer-to-peer (P2P) file-sharing application, and several BitTorrent-based P2P video streaming systems have been proposed in the literature. Nowadays, network address translation (NAT) has been widely used since it reduces the usage of IP addresses, but it is also considered as a factor that degrades the performance of P2P systems because NAT limits the direction...
We study a network structure for efficient information dissemination that leverages location-based real-time applications operating in a distributed system. Gossip-based information dissemination is a promising method for a large-scale system to keep nodes in the network quickly updated with new information. The information dissemination efficiency depends strongly on the underlying network structure,...
Multimedia sensor networks (MSNs), which allow capturing acoustic and visual information, provide an unprecedented opportunity for variety of applications. This paper investigates the heterogeneous coverage problem in MSNs, i.e., how many multimedia sensors should be deployed to guarantee that each point in the monitored region is covered by multiple types of heterogeneous sensors. It is different...
In this paper, channel assignment in cooperative spectrum sensing is studied for multi-channel cognitive radio networks. Based on the information from each secondary user, e.g., primary signal-to-noise ratios over all channels, a centralized scheme is proposed, which assigns channels to different secondary users for sensing so that the number of available channels, which meet the sensing performance...
In this paper, we consider the BER analysis of the constellation rearrangement (CoRe), which is not subject to the Gray-encoding constraint for the first transmission. This type of CoRe can be applied in a parallel transmission system such as cooperative relaying networks. Furthermore, it allow us to construct the accumulate constellation, which obtained by separating and rearranging the received...
Podaj zakres dat dla filtrowania wyświetlonych wyników. Możesz podać datę początkową, końcową lub obie daty. Daty możesz wpisać ręcznie lub wybrać za pomocą kalendarza.