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This paper aims to offer insight into the topic of discrete-time ΣΔ ADCs. More specifically, we investigate the impact of non-ideal analog subcircuit parameters on the performance of a 16-bit, 1 kHz, differential second order, 1-bit quantizer, sigma-delta modulator in a 180 nm technology. The parameters in question are OPAMPs slew rate and gain which fulfill the role of fully differential, discrete-time...
Thermal stress is one of many possible failure causes of power electronics systems; thermal cycles are known to produce mechanical fatigue on power electronic devices, thus leading to their failure in time. Temperature swing can be somehow controlled, if some decrease in efficiency can be tolerated by the power system, changing gate driver parameters to heat up the device in low load conditions. This...
Research conducted in the field of localization with passive light, or using the intrinsic properties of light to determine a person's location, has seen increased growth in recent years. Specifically, fluorescent lights have been shown to exhibit distinct frequencies which can be recorded, along with their positions, for future lookup and positioning. Developments have been made in utilizing this...
Jitter is inherent to the breakpoints of measured genome somatic copy number alterations (SCNAs). Therefore, an analysis of jitter is required to reduce errors in the SCNA estimation. The high resolution technologies of hybridization are used to detect SCNAs. However, the SCNA measurements are accompanied with intensive noise that may cause errors and ambiguities in the breakpoint detection with low...
High fluctuation of signal strength is evident in wireless channel under mobile environment. IEEE 802.11n and IEEE 802.11ac based wireless technologies experience a challenge for selecting link configuration parameters, like number of spatial streams, channel bonding, advanced modulation and coding schemes, frame aggregation etc., dynamically under mobility. Selection of the best possible data rate...
Viterbi algorithm (VA) applied to time frequency (TF) distribution is a highly performed instantaneous frequency (IF) estimator, but it suffers from switch problem (SP) at the intersected points of multi-components on the TF plane. In order to suppress the SP in VA, an improved VA (IVA) in this paper assumes the IF variation trends between two adjacent IF points are not large, then a new penalty function...
Visible light communication (VLC) offers the usage of visible light for data transmission as well as illumination, and is suitable for vehicle-to-vehicle/infrastructure-to-vehicle communication. However, existing VLC systems require high-speed camera to achieve high data rate. To achieve VLC with sufficient data rate using commercial devices (e.g., smartphones), VLC using low-speed image sensor and...
Transmission techniques based on channel coding with feedback are proposed in this paper to enhance the security of wireless communications systems at the physical layer. Reliable and secure transmission over an additive noise Gaussian wiretap channel is investigated using Bose-Chaudhuri-Hocquenghem (BCH) and Low-Density Parity-Check (LDPC) channel codes. A hybrid automatic repeat-request (HARQ) protocol...
In this paper, we investigate the cryptanalysis of stream ciphers, and evaluate the enhancement to security that can be gained when the ciphertext is error prone by analyzing specific attack algorithm. The stream ciphers that we investigate here have a keystream generator that is based on linear-feedback shift registers (LFSRs). In particular, we characterize the security of these ciphers when the...
In this paper, the system-level performance of nonorthogonal multiple access (NOMA) in coordinated direct and relay transmission (CDRT) is investigated. Considering a successive interference cancellation (SIC) receiver under the 3D channel model for LTE, the system-level performance of the NOMA-CDRT is compared to the NOMA in non-coordinated direct and relay transmission (nCDRT). Simulation results...
The integration of Device-to-Device (D2D) communication into a cellular network improves system spectral efficiency, increases capacity, reduces power consumption and also reduces traffic to the evolved NodeB (eNB). However, D2D communication generates interference to the conventional cellular network which deteriorates the system performance. In this paper, we propose a radio resource allocation...
In this paper, as a basic study for combination of turbo equalizer and 4D-8PSK-TCM (4 Dimensional 8 Phase Shift Keying Trellis Coded Modulation) system, which is recommended for X-band band satellite communication in CCSDS, a system combining 8PSK-TCM system and turbo equalizer has been designed and performance evaluation of the system has been performed. BER performance of 8PSK and 8PSK-TCM systems...
Recently, Single-Cell Point-to-Multipoint (SC-PTM) has been studied in 3GPP as an agile broadcast/multicast mechanism. Due to cell-level support of the multicast service, SC-PTM can adjust the service area dynamically and its scheduling is quite agile. In the conventional SC-PTM, however, a single multicast transmission is set for the worst user and provided for all the users regardless of their channel...
A new detection algorithm for direct sequence spread spectrum (DSSS) signals using peak-to-average power ratio (PAPR) is proposed. The received signals are divided into several blocks. Then we calculate peak-to-average power ratio of each block and we use the average of peak-to-average power ratios as test statistics. The advantage of the proposed algorithm is no need to estimate noise variance. Additionally,...
This paper considers a frequency-division-duplexing (FDD) massive multiple-input multiple-output (MIMO) system that operates with two-stage beamforming based on user grouping. In this system, we propose a first stage beamformer and a user grouping method for the two-stage beamforming. The proposed first stage beamformer maximizes an approximate sum rate calculated from the second-order statistic of...
This paper addresses the problem of acoustic noise reduction and speech enhancement in new telecommunication systems by adaptive filtering algorithms. We propose a new two-channel forward BSS algorithm based on signal prediction to give an automatic algorithm with a very nice behavior at the output. This algorithm is called the two-channel fast normalized least mean square (TCFNLMS) algorithm. This...
Polar coding is a low-complexity method for communication over noisy classical channels, which is capable of providing highly reliable data transmission. This paper proposes an enhanced polar codec scheme for mission critical applications in train-to-ground wireless communications. Firstly, we develop an enhanced polar coding scheme to support reliable data transmission under time-varying channel...
The explosive growth of wireless devices requires more aggressive and balanced spectrum sharing and the listen-before-talk (LBT) is still a superior candidate protocol for a high device density. The Modified hardcore point process (HCPP) type II model provides mathematically tractable performances for such LBT networks, but it underestimates the LBT performances. In this regard, this paper evaluates...
In our paper, a novel method is proposed to obtain the optimal positions of secondary base stations (SBSs) for cognitive radio Internet of Things (IoT) sensor networks and to select the optimal operating channel in order to maximize the secondary capacity, while also protecting the primary systems. We proposed an appearance probability matrix for secondary IoT sensor devices in order to maximize the...
In this paper, an effective method for minimizing a convex criterion is proposed to allow its application in solving inverse problems related to the X-ray tomography. Proximal algorithms associated to total variation regularization are used knowing that they have high quality to converge. The main objective is to obtain high quality reconstructed images. We applied this algorithm to non-destructive...
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