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 ad hoc position-location networks, location information is obtained through the sequential estimation of node locations. An unlocalized node can estimate its location based on range and location estimates of nearby localized (";anchor";) nodes, and subsequently provide range and location information to other unlocalized nodes in its vicinity. In such distributed location-estimation scenarios,...
This paper proposes a fast joint frame synchronization and frequency offset acquisition algorithm for OFDM systems. A training sequence composed by linear frequency modulation signals is superimposed on the data signal at the transmitter side. Then, by fractional Fourier transform the frame synchronization and frequency offset acquisition can be obtained from the received signal simultaneously. Even...
We consider a scenario in which frequency agile radios opportunistically share a fixed spectrum resource with a set of primary nodes. We develop a collaborative scheme for frequency agile radios to estimate the maximum power at which they can transmit, without causing harmful interference to the primary receivers. The proposed scheme relies on signal strength measurements, which are used to localize...
Localization is one of the fundamental problems in many wireless sensor networks applications. They require sensor nodes to obtain their absolute or relative geographical position. Although many localization algorithms have been proposed recently, most of them require the node to equip special range-determining or angel-determining hardware in order to obtain the position related information. In this...
Relying on a simple flag-assisted mechanism, a multi- group priority queueing (MGPQ) medium access control (MAC) protocol is proposed for the multipacket reception (MPR) channel. The proposed MGPQ scheme is capable of overcoming two major performance bottlenecks inherent in the existing MPR MAC protocols. First, the proposed solution can automatically produce the list of active users by observing...
This paper presents a distributed estimation scheme (DES) along with the bit allocation algorithm, which minimizes the total required bandwidth while ensuing a given average estimation mean-squared error (MSE). The DES comprises of a probabilistic Lloyd-Max quantization rule, and a best linear unbiased estimation (BLUE). Since the optimum bit allocation problem does not have a closed form, we present...
High node mobility and transient connectivity in vehicular ad hoc networks have introduced numerous challenges in the design of efficient communication protocols for these networks. Toward the goal of efficient design of such networks, the focus of this work is to develop methods that will allow the estimation of a wireless link's future quality and the remaining (residual) time for which this will...
Signal-to-noise ratio (SNR) estimation is an important issue in many communication systems. This paper proposed a new non-data-aided (NDA) SNR estimator for BPSK and QPSK modulated signals. The estimation is based on pseudo-error probability (PEP), which can be estimated without additional cost for sampled systems. The performance of the proposed estimator is examined numerically in terms of its bias...
The inter-modulation and cross-modulation products of interferences introduced by nonlinearities of the receiver could significantly degrade system performance, and should be properly estimated when determining system design specifications. In MB-OFDM UWB systems, the traditional two- tone technique is still widely used to estimate nonlinear effects. However, this technique is not accurate enough...
This paper presents a novel ring-based approach to analyze the inter-flow capacity of a backhaul wireless mesh networks (WMNs) with centralized scheduling. Based on the property of symmetric MAC protocols, an optimistic channel reuse distance is defined, which enables us to accurately describe a bottleneck collision area for a mesh network. Then, the upper bound of inter-flow capacity is derived by...
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.