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This paper presents a study on interference caused by Secondary Users (SUs) due to miss-detection and its effects on the capacity-outage performance of the Primary User (PU) in a cognitive network for two scenarios of beacon transmitter placement: beacon transmitter located at PU transmitter or at PU receiver. Interference analysis shows that aggregate interference power from SUs has a Gamma distribution...
The cognitive radio allows spectrum sharing between licensed users (primary users) and many unlicensed users (secondary users). The secondary users are only allowed to use a licensed spectrum in the absence of its rightful owner. Thus, the ability to accurately sense the presence of the rightful owners is highly essential. In this paper, a novel cooperative spectrum sensing (CSS) approach to efficiently...
In this paper, we propose a new cooperative spectrum sensing scheme to minimize the false alarm probability while satisfying the detection probability at a desired level. To improve the spectrum sensing performance, it is desirable for the cognitive base station to combine binary local decisions of secondary users by considering the local sensing reliability. In the proposed scheme, the local decisions...
In this paper, we introduce a new technique that allows the coexistence of secondary users (SUs) with a primary user (PU), in the same frequency and time. The proposed technique (i.e., the cluster-based spatial opportunistic spectrum sharing (CB-SOSS) technique) exploits the spatial degrees of freedom resulting from the use of multiple antennas at both the secondary base station (SBS) and SUs; also...
Secondary users, which base on the spectrum pricing function given by primary users, can compete the spectrum resource with each other through game theory in cognitive radio system. It can be divided into cooperative game and noncooperative game according to whether the secondary users cooperate or not in the spectrum sharing. In this paper, based on the Nash bargaining in cooperative game, an improved...
In this paper, we study the dynamic uplink power allocation problem in a multi-cell multi-user CDMA-based cellular cognitive radio (CR) system, in which the concept of hierarchical interference bound is introduced to describe the coexistence of the multi-user interference. We propose a novel differential game-based dynamic power allocation model via two formulated cost functions. Furthermore, we present...
Recently many papers proposed some game model for spectrum leasing in cognitive radio. But some of them just consider that how primary users manage the leasing spectrum, some of them just consider that how the secondary users to do their best to use the spectrum efficiency. So we propose a game model combining the advantages of their model and algorithm. In our model, the primary users manage the...
Collaborative spectrum sensing among secondary users (SUs) in cognitive networks is shown to yield a significant performance improvement. In this paper, we study the dynamics of a network of SUs in order to reduce the interference on the PU through collaborative sensing. While existing literature mainly focused on centralized solutions for collaborative sensing, we propose a collaboration formation...
The digital dividend has the goal to achieve a more efficient utilization of the UHF broadcasting bands by permitting access to cognitive radio devices. Thus, the conventional use of analog, narrow band devices by secondary users of the same frequency range is supressed. One traditional application of this type are common Professional Wireless Microphone Systems (PWMS). To maintain the production...
Cognitive radio has been proposed as the means for secondary users to promote the efficient utilization of the spectrum by exploiting the existence of spectrum holes. Meanwhile, cooperative diversity techniques can improve the transmission rate and reliability of wireless networks. In this paper, both the case of relay participating in the cognitive networks and the case of relay selection are considered...
Cognitive radio networks (CRNs) are envisioned to eradicate the artificial scarcity caused by today's stringent spectrum allocation policy. In this article, we develop a comprehensive statistical framework to study the transmission capacity (TC) of the primary network in the presence of collocated CRN operating under self-coexistence constraint. Considering a system model based on stochastic geometry...
We propose an adaptive resource allocation algorithm for a multiple-input multiple-output (MIMO) orthogonal frequency division multiple access (OFDMA) based downlink cognitive radio network (CRN). The CRN has multiple secondary users (SUs) coexisting with multiple primary users (PUs). The aim is to maximize the total data throughput of SUs while ensuring interference leakage to PUs is below a threshold...
The goal of this paper is to propose a distributed resource allocation strategy for the access of opportunistic users in cognitive networks. The opportunistic, or secondary, users are modeled as a set of agents looking for the most appropriate slots to use, in the time-frequency domain, with the goal of avoiding conflicts among themselves and to yield possibly no interference to the primary users...
This paper deals with dynamic resource allocation problem for OFDMA-based cognitive radio systems. The proposed solution is specifically tailored for a secondary base stations (SBS) transmitting to secondary users (SUs) over the same bands of the licensed primary users (PUs) in underlay fashion. The downlink transmission goodput is thereby maximized while keeping the interference on the PUs within...
We propose a robust signal to interference and noise ratio (SINR) balancing beamforming technique for a multiple input and multiple output (MIMO) based cognitive radio (CR) network. The aim is to design transmitter and receiver beamformers for multiple secondary users (SUs) while ensuring interference leakage to multiple primary users (PUs) is below a prescribed threshold. We use an iterative approach...
Orthogonal frequency division multiplexing (OFDM) suffers from significant out-of-band radiation due to high sidelobes of modulated subcarriers. In a cognitive radio (CR) system this effect results in high interference between secondary and primary users (PUs). Existing methods for reducing this interference have the drawbacks of significant data transmission rate reduction or power peak to average...
Dynamic spectrum access has become a promising approach to fully utilize the scarce spectrum resources. In this paper, two new dynamic spectrum access schemes for secondary users are proposed, which are based on continuous-time Markov chains (CTMC). Both the interactions between primary and secondary users and the effects of imperfect spectrum sensing(i.e. miss-detection and false alarm) are considered...
Cognitive Radio technology releases the spectrum from shackles of authorized licenses and facilitates the trading of spectrum bands. In the spectrum market, primary users (PUs) set prices for their vacant bands and sell them for monetary gains, and secondary users (SUs) buy the bands and opportunistically use them to satisfy their service demands when the PUs are not active. However, when there are...
It is widely accepted that the emergence of cognitive radio (CR) will lead to a wireless communication revolution. Spectrum sensing is one key process of CR, which makes effective use of scarce spectrum. Two novel schemes, clustering and locating schemes, are presented for spectrum sensing based on energy detection on the condition that there are multiple primary users in the cognitive radio network...
This paper focuses on the unslotted cognitive radio networks in which the secondary users (SUs) are not synchronized with the primary users (PUs). The SUs can opportunistically utilize the wireless channel as long as the channel is not occupied by the PUs. Due to the half-duplex nature of the wireless medium, the SUs may inevitably impose interference to the PUs because the SUs cannot precisely predict...
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