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.
This paper proposes a low-complexity signal detection algorithm for spatially correlated multiple-input multiple-output (MIMO) channels. The proposed algorithm sets a minimum mean-square error (MMSE) detection result to a starting point, and searches for signal candidates in multi-dimensions of the noise enhancement from which the MMSE detection suffers. The multi-dimensional search is needed because...
We consider the allocation of spectral and power resources every subframe (1~ms) on the uplink of the Long Term Evolution (LTE) wideband orthogonal frequency division multiple access (OFDMA) cellular network. System bandwidth is divided into multiple sub-bands. The fractional power control to manage interference is allowed to be a function of the sub-band. Moreover, the channel gains from the base-station...
Scheduling schemes of wireless networks determine packet transmission opportunities for each network node by considering network parameters such as link quality, transmission rate, and delay. However, security has not been taken into account in these schemes, although it plays a critical role in network performance. In this paper a new scheduling scheme is proposed to determine packet transmissions...
Cognitive radio (CR) has been recently proposed as a promising technology to improve the spectrum utilization. In this paper, we consider the spectrum sharing between CR users and a licensed primary user (PU) in order to enhance the spectrum efficiency. In the considered scenario, the PU is located at a far position from the primary base station (PBS) which makes it difficult to obtain a successful...
In this paper, optimal multiple channels cooperative spectrum sensing setting in non-identical environment is investigated. In previous work on cooperative sensing, all the secondary users have the same detection threshold and the noise received is independent identically distributed random variable. Thus researchers often assume that identical sensing time is assigned to the channels for spectrum...
We consider a simple closed-loop spatial multiplexing architecture which can be incorporated into an outer system with off-the-shelf single-input single-output encoders/decoders. Instead of relying on transmitter-side channel state information for matching the layers of the multidimensional signal to the eigenmodes of the multiple-input multiple-output channel through a precoding, the eigenmodes with...
Block Diagonalization (BD) algorithm is a generalization of channel inversion scheme in multiuser multi-input multi-output (MIMO) broadcast channels. Although the BD algorithm is effective in removing interuser interference, it has a drawback that additional information should be delivered to the receiver. Recent work on BD with vector perturbation (VP) avoids the need for additional information and...
In this paper, the impact of double-sided signal clipping on optical wireless communication (OWC) systems employing asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) is investigated. Time domain signal clipping is introduced due to biasing issues or physical limitations of the front-ends. These include insufficient forward biasing of the emitter and the maximum driving...
The identification of Internet applications is important for ISPs and network administrators to protect the network from unwanted traffic and prioritize some major applications. Statistical methods are widely used since they allow to classify applications according to their statistical signatures. They combine the statistical analysis of flow parameters, such as packet size and inter-packet time,...
This paper considers the problem of applying compressed sensing ideas to relay networks in order to increase the network throughput. We present a new method to perform forwarding which, when the signals transmitted by several sources are jointly sparse, enables to send a vector of dimension higher than the min-cut of the network. First, the jointly sparse source signals are mapped to a signal of lower...
Adaptive bit allocation for DMT-based systems is critical for preventing performance degradation due to poor allocation of bits given challenging channel conditions. In this paper, we extend the bit removal greedy algorithm to a multi-user environment. It has been proved that the proposed algorithm converges faster than the traditional multiuser greedy algorithm.
Communication via diffusion of molecules is an effective method for transporting information in nanonetworks. In this paper, novel modulation techniques called Concentration Shift Keying (CSK) and Molecule Shift Keying (MSK) are proposed for coding and decoding information of the so-called messenger molecule concentration waves in nanonetworks. The first technique, CSK, modulates the information via...
With recent advances in communication and data storage technology, an explosive amount of information is being collected and stored in the Internet. Even though such vast amount of information presents great opportunities for knowledge discovery, organizations might not want to share their data due to legal or competitive reasons. This posts the challenge of mining knowledge while preserving privacy...
The problem of spectrum sensing in multi-frequency cognitive radio systems is addressed. We show that as the sensed bandwidth increases, the primary user detection is governed by a low signal-to-noise ratio (low-SNR) regime. By means of low-SNR approximations, we show that the optimal generalized likelihood ratio test (GLRT) only depends on the second order statistics of the observations and on a...
A chaos-based key generation scheme is proposed and its performance analyzed. The method, the logistic map scheme, is applicable for use on wireless networks because it does not require devices to engage in computationally intensive algorithms. In addition, the method achieves reliability from the perspective of the communication agents, as well as randomness and unpredictability from the perspective...
Theoretical analysis has long indicated that feedback improves the error exponent but not the capacity of memoryless Gaussian channels. Recently, Chen et al. demonstrated that an incremental redundancy scheme can use noiseless feedback to help short convolutional codes deliver the bit-error-rate performance of a long blocklength turbo code, but with much lower latency. Such a latency improvement is...
Scaled largest eigenvalue based detection is an ideal solution to spectrum sensing problem in cognitive radio networks. However, results on the sensing performance are very limited. In this paper, we analytically investigate the detection performance by deriving simple and accurate test statistics distributions. These results are obtained by taking advantage of properties of the Mellin transform for...
High peak to average power ratio is a major drawback in orthogonal frequency division multiplexing (OFDM) systems. A high PAPR can lead to saturation in the power amplifier and consequently increase spectral spreading, distorts the signal, and reduces power amplifier efficiency. In this paper, we propose a method based on compressed sensing (CS) to recover nonlinearly distorted OFDM signals. The method...
Dynamic spectrum access has emerged as a promising paradigm for improving the Dynamic spectrum utilization efficiency of wireless networks. To enable this new paradigm, fast and accurate spectrum sensing has to be performed over very wide bandwidth in noisy channel environments under energy constraints. Cyclic feature based sensing approach works well under noise uncertainty, but requires very high...
Monitoring user states is one of the main applications in the e-Health field. This paper focuses on the assessment of speech discrimination for fitting the parameters of hearing aids using the electroencephalogram (EEG). The characteristic of our method is to utilize the event-related potentials (ERPs) to visual stimuli instead of the conventional auditory stimuli. A letter is played through a speaker...
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.