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On-chip wireless links operating at millimeter wave frequencies offer the most promising solution to overcome the multi-hop latency and high power consumption of metal interconnects in Network-on-Chip (NoC) platforms. Design of efficient transceivers, that are resilient to channel effects is essential to achieve high performance on-chip wireless communication. In this work, we present a spectrally...
This paper considers a K-cell multiple access channel with inter-symbol interference (ISI). The primary finding of this paper is that, without instantaneous channel state information at a transmitter, the interference-free sum degrees of freedom of K is asymptotically achievable when the number of users per cell is sufficiently large, and also when the number of channel-impulse-response taps of desired...
5G New Radio (NR) is envisioned to support three broad categories of services: evolved mobile broadband (eMBB), ultra-reliable and low-latency communications (URLLC), and massive machine-type communications (mMTC). The URLLC services refer to future applications that require secure data communications from one end to another with ultra-high reliability and deadline-based low latency requirements....
In this paper, we investigate the joint resource allocation policy for an orthogonal frequency division multiplexing (OFDM)-based cooperative cognitive radio network with statistical delay quality of service (QoS) guarantees. In the CR network, the spectrum leasing scheme operates in a situation where the primary users (PUs) lease part of its licensed spectrum to the secondary users (SUs) in exchange...
In target searching stage of radar seeker in modern encounter, the transmitted signal is required to have characteristics of high resolution, low probability of intercept and high Doppler tolerance. In order to overcome the disadvantage of OFDM signal's low Doppler tolerance, a new type of multicarrier signal with nonuniform frequency density is proposed, whose subcarriers and amplitude weighting...
We propose a method for channel estimation in orthogonal frequency division multiplexing (OFDM) systems with an array of receiving elements. In contrast to traditional methods, which target the equivalent sample-spaced channel taps, this method targets the physical propagation paths whose delays are not restricted to the sample-spaced grid. The path delays are estimated jointly with the path gains...
In this paper, we investigate the impact of linear mode coupling on the efficiency of intermodal four-wave mixing and on the group delay statistics in few-mode fibres. The investigation will include not only the weak or strong linear coupling regimes, but also the transition region between them, the intermediate coupling regime. This analysis will allow to assess the level of coupling strength require...
The satellite navigation is supposed to be used in applications that need coordinates generally. However we can meet a plenty of satellite signal reception problems in a real environment, often called as difficult conditions. The difficult conditions hinder reliable positioning with required accuracy, often in applications that are important for saving or securing the safety of human lives (work of...
Long Term Evolution (LTE) holds the promise to enhance the capacity and speed of mobile communication by supporting Multimedia Broadcast/Multicast Services (MBMS) over a single frequency network (MBSFN), where numerous cells transmit an identical waveform that is synchronized in time for a specific time interval. For improving the performance of SFN, ultra-extended cyclic prefix duration has been...
Intercell interference (ICI) is one of the major factors that limit the performance of wireless cellular network systems. Soft frequency reuse (SFR) as well as its modified algorithms such as Soft fractional frequency reuse (Soft FFR) and Distributed fractional frequency reuse (Distributed FFR) have been introduced as an effective way to optimize spectrum and control the ICI. However, the comparison...
In this paper, the time dispersion propagation measurements and the performance study of an OFDM system in a millimeter wave underground mine wideband wireless channel are addressed. Time dispersion and coherence bandwidth results are analyzed at both 40 m and 70 m levels of the mine. Different antenna configurations such as horn-horn and horn- omni in a line of sight (LOS) situation have been considered...
To reduce an adjacent channel interference (ACI) by sharpening the spectrum edges of the orthogonal frequency division multiplexing (OFDM) signal in the frequency domain, an windowing function is applied to the individual OFDM symbols in time domain. A commonly used windowing function is the raised cosine function with a roll-off factor. In this paper, the spectrum of an OFDM signal and −45 dB bandwidth...
The safety of on-duty firefighters in indoor environments could be increased by ensuring reliable, high-data rate communication in potentially life-threatening situations. This increases their situational awareness, strengthens their decision making and decreases response time by ensuring efficient indoor communication of sensor data, biometric data, pictures or videos. Therefore, a real-life rescue...
Due to the very large transmission bandwidth of millimeter wave (mmWave) communications, the fading channel is expected to be frequency selective. Recent work in this field has mainly focused on cyclic-prefixed OFDM as a method to combat the frequency selectivity. But in this paper, we shift the focus on the novel method of time delay compensation to obtain a flat channel over wide bandwidth since...
The millimeter Wave (mmWave) is considered as a promising technology of the future fifth-generation wireless systems due to the currently underutilized multi-GHz spectrum surrounding the 60GHz carrier frequency, particularly with the recent advances in low cost sub-terahertz semiconductor circuitry. Since the mmWave suffers high attenuation during transmission, the repeater is a key technique to enable...
In anticipation of the increasing demand of wireless traffic, WiFi standardization efforts have recently focused on two key technologies for capacity improvement: multi-user MIMO and wider bandwidth. However, users experience heterogeneous channel orthogonality characteristics across sub-carriers in the same channel bandwidth, which prevents ideal multi-user gain. Moreover, frequency selectivity increases...
In this paper, performance analysis and the effectiveness of Orthogonal Frequency Division Multiplexing (OFDM) for different channels environment has been analyzed and investigated. In order to accomplish these tasks, an OFDM system model has been considered where a random bit sequence is generated and subsequently converted into decimal value depending on the word size of the system. In order to...
Due to the rapidly time-varying nature of wireless channels, it is not possible to obtain accurate instantaneous channel state information (CSI). However, predicting and obtaining the velocity of the moving terminals is not difficult, where the velocity (mobility) can be considered as a large scale metric. A new concept called mobility adaptation is proposed for OFDM systems under rapidly time-varying...
This paper strives to improve the energy efficiency (EE) of wireless systems by resource allocation for delay sensitive traffic with the statistical quality of service (QoS) requirement, where a delay bound and a small violation probability is ensured. To avoid wasting energy when serving random traffic, we turn the QoS exponent, a key parameter to characterize statistical QoS guarantee under the...
Mobile Internet and Internet of Thing (IoT) have been widely recognized as the two major driven forces of next generation mobile systems (IMT-2020 or 5G). Key performance indicators (KPI) of 5G are identified to satisfy the needs of these applications, such as 10Gbps peak data and 1000× capacity increase. A common census has been reached in industry that high frequency and ultra dense small cell (5G...
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