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In order to use the idle spectrum effectively and improve the spectrum efficiency, cognitive radio technology has attracted ex-tensive attention. On account of low detection probability and low spectrum efficiency of previous spectrum sensing framework, a relay-based cooperative spectrum sensing framework is pro-posed and multiple narrow-band waveforms are required for different users which could...
In this paper, a distributed fair algorithm is proposed to address the resource allocation problem in the cognitive femtocell network. The cognitive functionalities equipped in femtocells enable us to effectively identify the qualified resource blocks (RBs), thus we can mitigate inter-cell interference. By exploiting the satisfaction degree and the channel state difference, the proposed distributed...
Orthogonal frequency division multiplexing (OFD-M)based cognitive radio networks (CRNs) is a promising paradigm to increase spectrum efficiency and achieve flexible resource allocation. However, previous works either lack the consideration of channel uncertainties or ignore the effect of imperfect spectrum sensing. In this paper, we focus on the power control for a downlink OFDM-based CRN with the...
Even though databases are currently favored in spectrum sharing scenarios, sensing is still needed. Spectrum sensing has a future in several existing and novel situations and applications. Those include crisis situations, local and indoor networks like wireless local area networks (WLAN) and battery-oriented applications like future intelligent Internet of Things (IoT). In this paper, the future of...
2.4GHz Industrial Scientific Medical(ISM) Band is shared by both WLAN and IEEE 802.15.4. Therefore, WLAN and IEEE 802.15.4 get interfered by each other where WLAN and IEEE 802.15.4 deploy locally. Especially, IEEE 802.15.4 devices are more influenced by the interference from LWAN devices because WLAN devices transmit data with higher power than IEEE 802.15.4 devices. In this paper, we proposed a possible...
In this work, we consider an underlay cognitive radio networks where the secondary transmitter transmits signal with power based on sensing result of the signal power transmitted by the primary transmitter. To improve the signal quality of the secondary transmission, we proposed an recursive algorithm to alternatively optimize multi-level power allocation and quantization regions of the sensing result...
Gait characterization and monitoring technologies are useful for the purposes of biometrics tracking and monitoring subjects (e.g., the elderly, at risk, and patients). Traditional techniques of measuring gait employ image processing or special sensors, which require either direct line of sight or physically attached sensors and thus, are cumbersome and costly. We propose Hoble that uses Wi-Fi signals...
In this paper, we address the challenges in facilitating the intra-band coexistence of WiFi and LTE technologies in multi-RAT networks and propose a semantic coordination protocol that improves the communication performance among inter-network devices. Effective communication in LTE networks is a critical task to achieve as the heterogeneity of the devices and coexisting technologies arises. This...
We study the problem of finding an efficient schedule for convergecast in a wireless sensor network, using the SINR model of interference, and a TDMA protocol for medium access. We compare two approaches to computing a minimum length schedule for the TDMA frame. In the first approach, called the TC-approach, a multi-set of transmission configurations that are interference-free and that cover the convergecast...
This paper introduces an extension of a methodology for calculating the average delay in a cognitive radio network using the slotted aloha technique for medium access. This extension includes two new aspects: imperfect sensing and different transmission power levels in the secondary stations regarding the channel state decision. The performance of the network is evaluated and numerical results are...
When wireless communication technologies are used in industrial networking, interference to these wireless devices is a major problem. This problem is more in ISM bands. Using licensed bands for industrial sensors and controllers by way of opportunistic spectrum access is being explored in the recent times. But searching by these wireless devices for the available vacant spectrum is a hectic task...
The Cognitive Radio is a smart wireless communication system that provides awareness about the radio frequency spectrum of its surroundings and rapidly reconfigures its operating parameters dynamically. It is a methodology to use the currently available spectrum momentarily without interfere the licensed user. This paper focuses on the challenges associated with network spectrum sensing, by employing...
Interference between automotive radars decreases the sensors' detection capabilities. It is possible to use digital beamforming (DBF) in multi-antenna systems to reduce the power received from certain directions of arrival (DoA). If digital beamforming is used to mitigate the effect of an interferer, it is shown that it is not sufficient to cancel the DoA of an interferer alone, if an I-Q mixer is...
Cognitive radio technology, which is designed to enhance spectrum utilization, depends on the success of opportunistic access, where secondary users (SUs) exploit spectrum void unoccupied by primary users (PUs) for transmissions. We note that the system behaviors are very similar to the interactions among different species coexisting in an ecosystem. However, SUs of a selfish nature or of misleading...
It was reported for specific bats, that they use a certain scheme to shift the frequencies of their echo location calls to counteract interferences with conspecifics. As in road traffic, an increasing number of cars is equipped with radar sensors, there is also the problem of mutual interference. The available frequency bands are limited, so a randomized frequency hopping will not be the best solution...
In this paper, we investigate the major trade-offs that relates to the energy efficiency in cognitive radio networks. We address five main trade-offs (QoS, network architecture, primary user interference, fairness and security) that are vital since they affect all the components of cognitive radio network's operability, design and implementation. The relationship between these trade-offs and how they...
The Internet-of-Things (IoT) is promising to inter-connect physical objects and machines in an intelligent network. In this context, scalable and resilient Machine-to-Machine (M2M) communication protocols are required, and the new Device-to-Device (D2D) feature of the 4G system constitutes an appealing solution. Standardization activities are still in progress, but the rapid diffusion of both LTE...
Currently, a number of different radio systems which are set up and work during a mission is growing rapidly. A traditional way to ensure coexistence of the radio systems and minimize interferences is a frequency allocation plan (pre-assigned frequencies) which is believed to be inefficient, whereas Dynamic Spectrum Access (DSA) is thought to introduce a more efficient spectrum usage. By using policy...
For search and rescue (SAR) missions in emergency and disaster scenarios, unmanned robotic technologies offer an opportunity to save human lives and speed up the rescue process. Communication among the unmanned devices and with the command and control station plays a key role in detecting, locating, and rescuing affected persons. To establish this communication network, ease of deployment provided...
The need for extra spectrum to support future 5G networks and the fact that a large amount of spectrum below 6 GHz is allocated for different radar systems have motivated regulatory bodies and wireless researchers to investigate the feasibility of Dynamic Spectrum Access (DSA) in radar bands. Moreover, the next generation of infrastructures and devices will need to be more flexible to support a much...
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