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 spatial aspect of distributed dynamic spectrum access (DSA) in a wireless ad hoc network is usually overlooked in the literature. By using tools from stochastic geometry, we analytically characterized the spatial distribution of users and subsequent interference in the network. Provided with multiple channels, users in the network interact in the sense that the channel selections they make affects...
In this paper, we propose an underlay spectrum sharing scheme where a secondary broadcast system shares the spectrum with a pair of primary users. Both primary and secondary users are discrete rate-power adaptive systems equipped with limited feedback of the channel quality information. By overhearing the primary feedback and receiving the feedback from each secondary receivers, the best secondary...
Due to the advancement of telecommunication platform, users are now demanding new applications such as Online Gaming, mobile TV, Web 2.0, and to meet this requirement operators needed to design more flexible network. For the deployment of this network, 3rd Generation Partnership Project (3GPP) works on the Long Term Evolution (LTE) and propose a system which has larger bandwidths (up to 20 MHz), low...
In this paper, we propose a statistical estimation framework to estimate Primary User (PU) transmitter locations by using the spatial characterization of spectrum usage in a collaborative spectrum sensing context in Dynamic Spectrum Access (DSA) networks. First, a statistical likelihood model of the received power by collaborating Secondary Users (SUs) is constructed by assuming a propagation model...
In a MIMO cognitive radio network, multiple secondary users sense the spatial channels and share the spectrum with incumbent primary users. Each secondary transmitter competes with others to increase its own information rate while limiting interference to the primary receivers. In this paper, we consider the interference constraint as the total interference power at the primary receiver caused by...
Cognitive-radio-networks with multiple input multiple output is an effective method to improve spectrum efficiency. Linear pre-coders is a crucial technology to realize this goal. However, most of existing algorithm developed based on the Gaussian input assumption. This assumption limited the application of linear precoding and caused great performance loss. In this paper, for such a problem, a linear...
Efficient spectrum utilization is of great importance in cognitive networks, however current spectrum sharing techniques in the temporal or spatial domains all have deficiencies. In this paper, we propose a joint spatial and temporal spectrum sharing scheme based on the concept of regions. We define four regions, namely a primary exclusive region (PER), a temporal spectrum sharing region (T-SSR),...
Cognitive radio is a promising technology to improve the spectrum utilization by allowing the unlicensed (secondary) user share a frequency bandwidth with the licensed (primary) owner under the condition that no harmful interference is imposed on the licensee. In this paper, we analyze the spatial spectrum utilization efficiency of underlay cognitive radio transmission. In particular, we apply the...
In this paper, we investigate the stability of a cooperative cognitive system. We propose a cooperative secondary transmitter-receiver system (CSTR), where, the secondary transmitter (ST) and the secondary receiver (SR) increase the spectrum availability for the ST packets by relaying the unsuccessfully transmitted packets of the primary transmitter (PT). We assume receiving nodes with multipacket...
Cross-border coordination of radiocommunications services is a very important aspect of spectrum engineering, crucial for network feasibility in countries' border areas. It is an ongoing activity, with a purpose to assure uninterrupted operation of different (or the same) radiocommunications networks between two or more neighboring countries. The ever-growing introduction of new technologies and services...
Protection of the primary users (PUs) from interference stemming from secondary user (SU) transmissions is one of the key issues in dynamic cognitive radio systems. Assuming elementary direction of arrival (DOA) or location estimation of PU devices can be carried out in the SU devices, appropriate directional transmission utilizing e.g. antenna arrays and null-steering can then be deployed to avoid...
In TV-band white space, the digital television (DTV) spectrum always make free or no-use spectrum when performing its actions in its spectrum range. So that, TV band devices (TVBDs) wishes to use this spectrum but not cause the harmful interference to DTV system. Besides, DTV spectrum can tolerate the interference from other system with their threshold. The sharing spectrum regulation that guarantee...
Long Term Evolution (LTE) is a standard for wireless communication of high speed data for mobile phones and data terminals. LTE is capable of delivering large data rate on the order of several megabits per second, which is even larger than the current 3G systems. This is very challenging as the wireless networks are subjected to interference, multipath and poor propagation channel characteristics...
With the rapid development of heterogeneous wireless technologies, the issue of how selfish wireless users can share spectrum is becoming increasingly relevant. In this paper we introduce the generalized spatial congestion game (GSCG), and use it to model wireless spectrum sharing over a large area. The idea behind the GSCG is to think of the players as vertices in a weighted graph. The amount of...
This paper presents the two strategies of jointly-optimized uncoordinated beamforming algorithms for cognitive radio networks. Here, we evaluate the performance of signal-to-interference-plus-noise ratio (SINR) and achievable sum rate of the system when both primary and secondary users transmit concurrently over the same spectrum. We present the optimum weight design to maximize the SINR and achievable...
In this paper, we propose a simple theoretical model to compute the maximum spatial reuse feasible in a VANET. We focus on the ad hoc mode of the IEEE 802.11p standard. Our model offers simple and closed formulae on the maximum number of simultaneous transmitters, and on the distribution of the distance between them. It leads to an accurate upper bound on the maximum capacity. In order to validate...
The Department of Defense (DoD) is developing policy-based spectrum management (PBSM) concepts, architectures, and capabilities to improve DoD's use of the electromagnetic spectrum, particularly in the area of edge networking. This use of PBSM is a paradigm shift in the way DoD will manage the use of the electromagnetic spectrum in support of Dynamic Spectrum Access (DSA) enabled Policy Based Radios...
There are two common spectrum sharing modes for cognitive radio (CR) networks: underlay and overlay. By a combination them, we propose here the hybrid spectrum sharing (HSS) model, where the transmission power is changed according to the states of the occupied sub carrier and interference constraints and thus, cognitive users can dynamically handoff between the overlay mode and the underlay mode....
In cognitive radio systems, the available frequency bands are usually non-contiguous, which may cause impact on the spectrum utilization efficiency (SUE).When the receiver has a limited sampling capability, the aliasing phenomenon may cause interference among the signals at different frequency points, thus causing the loss of channel capacity. Information theoretic analysis is carried out to quantify...
Simulation approaches and results are provided for Dynamic Spectrum Access (DSA) with remote wide-area spectrum monitoring equipment and moderate delay in spectrum data dissemination. Issues expected to arise using this approach include information delay time, failure to detect all transmitters, transmitter location errors, poor transmit-power estimates, and errors in the propagation model used to...
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.