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Energy efficient cognitive radio networks can simultaneously improve spectrum efficiency (SE) and energy efficiency (EE) of wireless communication networks. This paper studies energy efficient spectrum sensing interval, spectrum sensing energy and transmit power allocation scheme of the secondary user (SU) in CR networks. The EE maximization problem subject to the transmit power constraint and average...
Interference alignment (IA) is a prospective method to manage interference between users in multi-user networks. On the other hand, jamming can be an effective way to combat adversarial eavesdropping for legitimate networks. In this paper, a beneficial jamming scheme is proposed for interference alignment networks. In the scheme, the jammer utilizes its precoding vector to constrain the jamming signal...
In recent years, numbers of non-orthogonal multiple access (NOMA) schemes have been proposed to support the great amounts of wireless connections. However, complex multi-user detection is needed in case that the user power differentiation is not available and simple successive interference cancellation cannot directly apply, which usually incurs unaffordable computational complexity. In this paper,...
Due to the low out-of-band emission and robustness against asynchronous transmissions, generalized frequency division multiplexing (GFDM) has potential to be a new modulation scheme for the foreseeable applications. In this paper, a novel precoding scheme with tunable band sizes is proposed for GFDM systems. The precoder and equalizer are jointly designed aiming at minimizing the system total mean...
The emerging market of the Internet of Things (IoT) requires new energy-efficient and low-complexity Multiple-Input-Multiple-Output (MIMO-) aided radio access technologies. This trend will have a profound impact on both the theory and practice of future communication networks, which will not be purely optimized for approaching the attainable capacity anymore, but will explicitly include the energy...
Indoor target tracking has garnered interest as communication systems and mobile device capabilities advance. Visible light communication (VLC) is an alternative to RF methods that uses light emitting diodes. In this paper, probabilistic filtering algorithms (particle and extended Kalman filters) are used for indoor tracking. The performance of the filters is compared with an another positioning method:...
We outline guiding principles for choosing the subband bandwidth of a multicarrier system with multiple antennas. Initially, we review considerations for the choice of bandwidth in fast-fading doubly dispersive channels. We append to these considerations those relevant to the use of multiple antennas for intereference rejection in the wideband regime. To weigh the benefits of narrow subbands, which...
Electromagnetic interference can cause severe performance degradation on wireless communication systems. In modern military platforms there are many closely located electronic systems, which could potentially cause interference. The performance degradation is largely affected by the characteristics of the interference. With knowledge of the actual interference environment, radio receivers can be adapted...
Compared to conventional radar systems, passive coherent location (PCL) systems utilize transmitters already deployed within an environment. In this paper, we investigate PCL systems to estimate an unknown target position in three dimensional space, and propose a target-tracking process of three steps: 1) receiver selection, 2) target-tracking algorithm, and 3) filtering process. To reduce an estimation...
Massive machine type communication (mMTC) is one of the three significant scenarios in 5G, which is characterized by massive connection and low energy consumption. To meet these requirements, the contention based grant-free sparse code multiple access (SCMA) transmission which can support a large number of devices and reduce the cost of signaling overhead caused by massive connection is proposed....
Although a number of asynchronous physical-layer network coding (PNC) schemes have been proposed, synchronous PNC may still be preferred for its simplicity. In this paper we propose a new symbol-level synchronization scheme which reduces the misalignment to less than one hardware clock cycle period. In addition, we prototype the proposed scheme on the Universal Software Radio Peripheral (USRP) platform...
Tire Pressure Monitoring Systems (TPMS) offer real-time diagnostics of the status of a vehicle's tires via a wireless communications link back to the vehicle. These links, which provide data, mandated by the NHTSA, generally possess low security/low privacy, leading to a demonstrated potential for spoofing attacks or tracking a person/vehicle through the unencrypted emission of the tire's unique identifier...
Dynamic Spectrum Access (DSA) based Cognitive Radio (CR) allows a secondary user (SU) to use spectrum in an opportunistic manner when the primary user (PU) of that spectrum is not transmitting. Conventional dynamic spectrum allocation methods deal with acquiring spectrum as fixed width channels. In this paper, we propose a novel technique where a node inside a network can dynamically access the spectrum...
In modern systems, where many equipment are controlled by electronic devices, power transmission and distribution networks are increasingly turning into “smart grids”. There is the question of the immunity of these equipment to the action of electromagnetic fields generated by other equipment, as well as the immunity of other control and monitoring devices to the action of electromagnetic fields generated...
A three dimensional (3-D) channel model including both stationary and moving scatterers for high altitude platforms (HAPs) multiple-input multiple-output (MIMO) communication systems is proposed in this paper. An M-step 2-state Markov process is incorporated into this model to depict the reappearance behavior of both scatterers. The survival probabilities of scatterers are derived by using Chapman-Kolmogorov...
In this paper, an adaptive error concealment method is proposed to recover the motion vectors of degraded macroblocks (MBs) in a frame, based on analyzing the behavior of the MBs in the frames. In this method, the behavior of the degraded MB is first estimated considering the obtained information from motion vectors of neighboring MBs in the current frame and collocated MBs in the previous frames...
We propose an underlay decode-and-forward cognitive (UDFC) scheme under joint effects of hardware impairments at secondary users and interference constraints at multi primary receivers. In this scheme, the transmit powers of a source node and relays are constrained by interference thresholds of primary receivers in which the best relay is selected has the highest decoding capacity from the source...
Recently underwater wireless communication has been receiving a lot of attention as it is essential to facilitate new industries and applications such as deep sea mining, ocean monitoring, submarine communication, and so on. Latest studies have showed Space-Frequency Block Code (SFBC) OFDM which was studied thoroughly in radio wireless communication is a promising candidate for underwater acoustic...
For mainland-island communication applications, radio-over-fiber (RoF) links which have been commonly designated for short-reach access networks need to be re-designed due to the long geogrgphical distance nature. In this paper, we present a calculating model of long-distance RoF communication systems that connect mainland and islands using intensity modulation (IM) technique, two erbium-doped fiber...
This paper proposes an enhanced version of multicarrier differential chaos-shift keying (MC-DCSK) scheme using quadrature modulation (QM), namely QMC-DCSK. In the proposed scheme, the chaotic spreading sequence is transmitted on a predefined frequency the same as in the conventional MC-DCSK, while each of the remaining frequencies is phase-shifted an 90◦ angle in order to produce two quadrature sub-carriers...
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