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 paper, the problem of distributed beamforming for cognitive radio systems with frequency-selective channel is studied. Our proposed scheme is based on the filter-and-forward (FF) relay beamforming approach and aims to maximize the received signal to interference plus noise ratio (SINR) at the secondary destination, while suppressing the interference introduced to the primary user. This scheme...
In this work, we study the problem of interference in a two-tiered uplink network which contains a macro-cell and multiple small-cells. We null the interference from small-cells to macro-cell by using Vandermonde-subspace frequency division multiplexing (VFDM). VFDM can exploit frequency selectivity and null space generated by the cyclic prefixes (CP) used by the macro-cell communication. We use an...
Optimal power control for relay-assisted cognitive radio networks in which secondary users are assisted by cognitive relays is investigated. A monomial approximation based distributed geometric programming algorithm (MaDGP) is developed to maximize the secondary system utility under the individual and total power constraints of secondary users as well as the interference temperature limits of the...
Optimal power control for relay-assisted cognitive radio networks in which secondary users are assisted by cognitive relays is investigated. A monomial approximation based power control algorithm (MaPC) is developed to 1) maximize the secondary system weighted sum rates; 2) minimize the secondary system weighted sum powers under the individual and/or total power constraints of secondary users as well...
Many papers have studied the joint optimal transceiver design based on the assumption that channel state information (CSI) is perfect at both sides of transceiver, the same imperfect CSI is available at both ends or that transmitter has knowledge of channel distribution. To our knowledge, little effective work has been done on the practical situation that transmitter only knows the imperfect CSI different...
Because of the lack of dedicated frequency bands, the TD-LTE system is possibly deployed in the same band with other existed mobile systems. In this paper, the coexistence studies for the TD-LTE system with the radar system which has been widely deployed in the band 2300-2400 MHz, is presented. The dynamical system simulation methodology is utilized in the coexistence studies, and simulation results...
Cognitive radio is observed as a new approach, which could be cope with the spectral limitations. This approach is designed to detect whether a particular segment of the radio spectrum is currently in use and to jump into the temporarily unused spectrum rapidly without interfering with the transmissions of other users. CR is the promising radio technology which aims to detect and utilize the temporally...
In cognitive radio networks, secondary users (SUs) opportunistically exploit the spectrum unutilized by primary users (PUs). In this paper, we study the secondary communication where secondary transmitters and receivers have different available spectrum. Considering the spectrum diversity and the space distance between different PUs, we introduce cognitive relay node into the secondary communication...
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.