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The underlay cognitive radio that allows an unlicensed user to access the spectrum owned by the primary user even during its transmission but under tight interference constraint that protects the primary user which in the contrary affects the performance of the secondary one, is a very challenging investigation. We reduce the symbol error probability by improving the performance of the instantaneous...
The underlay cognitive radio that allows an unlicensed user to access the spectrum owned by the primary user even during its transmission but under tight interference constraint that protects the primary user which in the contrary affects the performance of the secondary one, is a very challenging investigation. Benefiting from antenna selection spatial diversity technique, we develop the instantaneous...
Visible light communication (VLC) systems have significant potential for enabling broadband data rates by relying on existing lighting infrastructure. In this paper, we investigate the performance of multi-element VLC transmitter architecture for different transmitter configurations. In particular, we consider multi- element transmitters with three, seven, and nineteen light emitting diodes (LEDs)...
Licensed-Assisted Access (LAA) using Long Term Evolution (LTE) is a promising technique to extend the available bandwidth by aggregating the unlicensed spectrum. To guarantee fair co-existence of nodes deployed by different operators and different RATs, listen-before-talk (LBT) mechanism and carrier selection can be adopted by LAA as efficient candidates. In this paper, we provide insight into the...
In this paper performance of a cognitive relay network (CRN) is studied under imperfect channel state information (CSI) where a secondary user (SU) transmits using a decode and forward (DF) relay. The DF relay is assumed to harvest energy from the radio frequency (RF) signal transmitted by SU. The performance is evaluated in terms of throughput in an underlay scenario with the energy harvesting relay...
In order to optimize the use of the frequency spectrum is often performed frequency sharing between two or more service providers. The Government of Indonesia through PERMENKOMINFO number 25 in 2014 allow the use of frequency sharing between the Fixed Satellite Service and Fixed Service in extended C-Band frequency. Frequency sharing conditions can lead to potential interference so both services need...
We study the robust security-aware beamforming optimization for cognitive interference channel with confidential messages under the imperfect channel state information (CSI) at each cognitive transmitter. The considered problem is formulated as minimizing the total secondary transmitter power under the subject of the each secondary transmitter constraint while guaranteeing the security communication...
Energy-efficiency, high data rates and secure communications are essential requirements of the future wireless networks. In this paper, we develop a framework to study the energy efficiency for enhancing physical layer security (PLS) in large-scale random cognitive radio networks (CRNs) considering the node spatial distribution, wireless propagation medium and aggregate network interference. Using...
We investigate a cellular-aided overlay device-to-device (D2D) network where a base station (BS) has a perfect control of all D2D operations such as pairing and link scheduling, and there exist no mutual interference between D2D communication and cellular communication because they do not share radio resource. Although optimal sum-rate can be theoretically achieved if the BS has perfect channel state...
This paper studies the feasible solution of power control for cognitive radio networks in the presence of primary user. The primary user (PUs) allows the secondary users (SUs) to spatially reuse the spectrum as long as they do not disrupt the communication of the former user. In addition, the primary user is willing to adjust its transmit power to meet the Signal to Interference Ratio (SIR) target,...
In this paper we investigate energy-efficient cooperation for secrecy in cognitive radio networks. We consider a four-node cognitive scenario where the secondary receiver is treated as a potential eavesdropper with respect to the primary transmission. In particular we consider three transmission schemes for the secondary transmitter, namely pure cooperative jamming, clean relaying, and interference...
In this paper, joint beamforming and power allocation via cooperation feedback and local feedback is considered in cognitive radio (CR) downlink where primary user (PU) coexists with multiple secondary users (SUs). The objective is to maximize the sum-rate of SUs while satisfying interference power constraint to PU and the total transmission power constraint of SUs. To effectively mitigate the interference...
Databases have been considered in the context of spectrum sharing systems to collect information on spectrum usage by primary users and to provide information on spectrum opportunities to secondary users. We develop a database-aided distributed channel assignment protocol (CAP) for secondary access control in a spectrum sharing system. Based upon a slotted, multichannel random access system model,...
In an underlay cognitive radio network, the secondary (underlay) transmitters generate interference to a primary receiver, while an underlay receiver is subject to interference from both the primary transmitters and other underlay transmitters not associated with it. Although guard regions, maximum allowable underlay transmit powers, and contention distances help guarantee a minimum performance to...
Transform domain communication system (TDCS) is a multi- carrier cognitive radio (CR) technique which uses cyclic code shift keying (CCSK) for overlay opportunistic spectrum access. Specifically, at any given time, a TDCS system cyclically shifts a fundamental modulation waveform (i.e., a CR sequence satisfying a dynamic spectrum hole constraint) according to specific input data symbol. In practical...
Interference in the vicinity of a receiving radio system can cause serious degradation of the radio communication performance. This may even result in disruptions and lost calls. Existing analysis tools to analyze interference problems in advance are often specialized at certain radio technologies or so complicated that they can only be used by experienced specialists. To foresee and prevent such...
In this paper, we build a unified analytical framework that allows for analysis and comparison of three device-to-device (D2D) mode selection schemes proposed in the literature to date, namely the distance cut-off scheme, the link gain scheme and the guard zone scheme. In the framework we adopt Poisson point process (PPP) assumptions to model the cellular and D2D interference, respectively. Using...
In recent years, the device-to-device (D2D) proximity services in the long term evolution advanced (LTE-A) system drew much attention and was standardized in LTE Release-12 (R12). Device discovery is a fundamental aspect of D2D proximity services, allowing discovery user to advertise its presence and/or discover others in its neighborhood. In this paper, the main D2D discovery aspects defined in LTE-A...
We consider a two-user interference channel assisted by a relay. Treating interference as noise at the receivers, and adopting an amplify and forward (AF) strategy at the relay, we derive achievable rates of both users, for given powers. Next, we solve the optimal power allocation problem maximizing the weighted sum rate of both users with and without relay power optimization. In particular, we propose...
We study the energy-optimal subcarrier power allocation for OFDM-based cognitive radio (CR) networks. A CR transmitter communicates with CR receivers on a channel borrowed from licensed primary users (PUs) when PUs' transmission are detected absence on those channels. Due to non-orthogonality of the transmitted signals in the adjacent bands, both the PU and the secondary user (SU) cause mutual-interference...
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