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Cognitive Radio (CR) is novel technology which provides a great solution to genuine lack of range and radio assets in today's situation, intellectual radio offers extraordinary arrangements. Cognitive radio is a pioneering technology which has a capability to improve the effective utilization of valuable natural resources. Cognitive Radio Network (CRN) is a vital wireless communication system that...
This paper describes an automated design approach to obtain continuous-time ΣΔ modulators with non-rectangular and even multiple DAC feedback waveforms using www.sigma-delta.de. There already exist well known techniques to calculate the necessary high-level coefficients for DAC waveforms other than non-return-to-zero. However, these calculations require expert understanding of ΣΔ modulators and get...
In this paper, the achievable rate of buffer-aided diamond relay systems under delay constraints is studied. The effective capacity, characterizing the maximum constant arrival rate to the source while satisfying the end-to-end delay constraints, is obtained for fixed decode-and-forward (DF) relaying schemes and selective relaying protocols. A selection relaying policy that maximizes the delay exponent...
With increasing data rates in communication systems, the call for wideband transceiver solutions capable of processing complex modulation schemes is getting stronger. Unfortunately, this goes along with power hungry systems and more complex integrated circuits. A novel receiver architecture, which addresses these issues, is based on the simultaneous phase and amplitude regenerative sampling system...
The rapid development of the Internet of Things (IoT) has brought big challenges to the traditional cellular networks such as super dense devices and deep fading channels. These new challenges will lead to a significant transmission efficiency degradation and increase the device's power consumption, especially in the uplink. A huge pressure will be also imposed to the enhanced Node B's (eNB) scheduler...
Abstract-In this paper, we develop a flexible and accurate analytical model of large networks with random base station (BS) placement, in order to understand the impact of key network parameters like BS density and load on the network performance. The main goal is to understand the flow level dynamics of such a system, assuming non-saturated users and studying the congestion statistics for BSs and...
A two-stage beamforming (BF) approach is proposed for millimeter wave (mmWave) cellular networks, wherein each base station (BS) first obtains wide beams to its users during the initial access (IA), then refines to narrow beams during the beam refinement phase (BRP). The performance of the proposed approach is derived under three IA protocols. Compared to a single-stage approach where beam searching...
We propose a compressive radar that uses single bit quantization of the received noisy signal. The one-bit quantization is performed by a comparator with a time-varying reference level. The problem is studied through a sparse method, leading to an optimization problem which can be solved numerically. Simulation results show that the proposed method has a promising performance.
As part of a larger scope work that studies network-based positioning, that employs timing measures, this article proposes a methodology to add Cramer-Rao Bounds (CRBs) information to the propagation model. Moreover, it enables a very quick computation of CRBs for timing, avoiding the growing computational effort resulting from Fisher's matrix formulation and its inversion for each required position...
With the rapid growth of capacity demand of railways around the world, Communication Based Train Control (CBTC) system, which is usually used in moving block signaling system to shorten the headway, is adopted by more and more countries. The railway operator in Beijing, the Beijing Subway, is no exception. In order to improve the train operation to meet the capacity demand, the Beijing Subway is interested...
In next generation networks, ultra-dense small cell networks are emerging to deal with exponential data traffic increasing. With the deployment of small cells (SCs) becoming increasingly dense, these cells may be under-utilized during quite a few period of time. Depending on this circumstance, we aim to maximize the network energy efficiency by deactivating such under-utilized cells, subjecting to...
In this paper, the effect of feedback delay and channel gain difference (CGD) on the performance of distributed transmit diversity (DTD) systems are analyzed over Rayleigh fading channels. We derive new expressions for the average error rate of DTD in the absence of receiver phase compensation (RPC), which is useful for a large number of modulation schemes. Furthermore, we analyze the effect of feedback...
Current public safety (PS) networks support mission critical voice communication, but are limited to narrowband data. As long term evolution (LTE) is the most widely deployed broadband communication technology so far, efforts are being made to develop LTE-based mission critical PS communication systems. In this paper, we propose delayed-response-based device discovery to support the application of...
In this paper, we study the secrecy outage probability (SOP) of an opportunistic relay selection scheme where an optimal relay is selected based on the delayed feedback from the multi-antenna destination. We present a new exact closed-form expression of the SOP, and two kinds of asymptotic form of SOP are further derived to explicitly show secrecy performance. In addition, we show that the SOP can...
In this paper, we propose a relay selection method in an amplify-and-forward (AF) scenario considering complete outdated channel state information (CSI) of all links. Differing from the methods in the literatures considering only outdated CSI over the link from the relay to the destination, another type of outdated CSI, i.e., the outdated CSI over the link from the source to the relay, is also considered...
The energy efficiency is important in all kinds of activities, and in industrial processes it's a very important factor both economically and environmentally. In the grinding processes, the energy efficiency is determined as much by the current that needs the motor of the mill as of the time that delays the grinding process, these two variables remain determined by the speed on which it feeds on product...
The operation algorithm of a multilateral time difference of arrival intelligence system, which enables to locate and to pursue the targets at the low signal to noise ratio at the output of intermediate frequency amplifier, is proposed in the paper.
Conventional echo hiding methods have simple encoding and decoding process, Robustness to MP3 compression, but the correct rate of extracted information need be improved. To copy with this problem, we propose a time-spread echo with random intervals. The encoding process generates an interval sequence to dominate the intervals of echoes. The echo is added into the audio according to the interval sequence,...
The Sub millimeter Array (SMA) was recently upgraded with a new wideband correlator that features a built-in beamforming system. This functionality enables the array to participate in a wider range of astronomical observations, such as Very Long Baseline Interferometry (VLBI) experiments, which require coherent combination of the signal-of-interest received by each element in the array. At millimeter...
In this paper, we investigate the impact of the pre-filtering method to generalized cross-correlation (GCC) based direction of arrival (DOA) estimation. The role of pre-filtering is either to emphasize or deemphasize certain frequency components before computing cross power spectrum. However, its impact or relation to environmental variation, e.g., in noisy environments, has not been clearly studied...
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