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Geo-locating moving targets using sequential imaging while exploiting their spatio-temporal proximity is addressed in this paper for bistatic Linear Frequency Modulation (LFM) and Orthogonal Frequency-Division Multiplexing (OFDM) scenes. The approach consists of three major steps (i) Synthetic Aperture Radar/Along-Track Interferometry (SAR/ATI) imaging for moving target detection; (ii) target velocity...
The performance of Device-to-Device (D2D) commu- nications in a cellular network depends on the resource sharing scheme between D2D links and cellular users. Existing research on resource sharing mainly focuses on power allocation under the condition that each D2D pair shares one cellular user's entire resources upon approval. Unlike conventional resource sharing schemes, this paper focuses on the...
Increasing demand by wireless communication applications for spectrum bands predominately occupied by radar applications has led to challenging resource allocation issues in the congested spectrum environment. A new resource allocation scheme based on Marginal Fisher's Information (MFI), is proposed to address the issue of spectrum congestion. Using MFI, which in some cases is identical to integrated...
Optical orthogonal frequency division multiplexing (O-OFDM) technology, which divides fiber bandwidth into multiple OFDM subcarriers, enables high bandwidth and fine granularity intra data center networks (DCNs) to provide powerful platform for cloud computing. An important issue raised in such O-OFDM based intra-DCNs is how to assign contiguous subcarriers for connection requests with the aim to...
Orthogonal Frequency Division Multiplexing (OFDM) is designed to combat the effect of multipath reception, by dividing the wide band frequency selective fading channel into many narrow flat sub- channels, which improves the spectral efficiency and significantly mitigates the intersymbol interference (ISI). However, OFDM can not meet the demand for 5G heterogeneous service scenarios since it has a...
Inter-cell interference (ICI) is one of the most important problems facing the planning of cellular networks which depends on Orthogonal Frequency-Division Multiple Access (OFDMA). Mainly, it affects the throughput performance of the cellular system. Many schemes are adopted to mitigate ICI. This paper deals with the co-channel interference (CCI) coordination and avoidance method defined as Fractional...
A method for joint estimation of the speed of a vehicle and its distance to a road side unit (RSU) for narrowband orthogonal frequency-division multiplexing (OFDM) communication systems is presented. Spatial filtering and a Maximum Likelihood (ML) algorithm are developed for distance estimation. The vehicle speed is calculated using a kinematics model based on the estimated distance. Numerical simulations...
Many-element antenna arrays, used for multi-user MIMO, are expected to be one of the cornerstone technologies for 5G wireless systems. Large arrays also offer the opportunity to average out some of the transceivers' analog imperfections, potentially enabling a lower-power implementation. In this paper we study the effect of local oscillator phase noise on beamforming MU-MIMO-OFDM systems. We show...
Adjacent channel interference (ACI) is often not considered when spectrum sharing schemes are designed for cognitive radio networks (CRNs). In practice, it is necessary to avoid interference by deploying guard bands between two distinct receptions. However, using guard bands typically reduces spectrum efficiency. In this work, we study the impact of guard bands on spectrum efficiency under different...
Research in Underwater Communications is tremendously growing now-a-days. Because of changes in undersea environment and multipath fading, it has become a challenging task for the researchers and scientists to communicate underwater. This paper describes various signals that can be passed through underwater and also the factors influencing them. Various techniques used for underwater communication,...
Non-orthogonal multiple access (NOMA) is a key enabling technology for fifth generation (5G) wireless networks because of its ability to provide greater spectral efficiency. However, a conventional NOMA scheme offers significant interference and higher outage probability especially when the number of users in the network is large. Therefore, in this paper, we propose a suboptimal algorithm which uses...
Channel aggregation (CA) techniques can offer flexible channel allocation and improve overall system performance in multi-channel cognitive radio networks (CRNs). Although many CA techniques have been proposed and studied, the impact of guard-band on CA for channel access has not been addressed in-depth. In this paper, we study the guard-band allocation mechanisms in discontinuous-orthogonal frequency...
Enhanced-Multimedia Broadcast Multicast Service (eMBMS) technology enables Long Term Evolution (LTE) networks to provide an efficient delivery of broadcast services. When eMBMS is applied for TV broadcast over large areas, the durations of Cyclic Prefixes (CPs) in the current 3rd Generation Partnership Project standard limit the network deployment options that can be used in practice. This paper considers...
In an SC-FDMA uplink network, where the universal frequency reuse factor is one, heavy inter-cell interference in the same sub-band between adjacent cells is induced and it significantly degrades the system performance. Current interference suppression methods focus on power control and resource allocation without considering the signal's time-frequency distribution characteristics. Different from...
In this paper we investigate the mobility effects impact on the millimeter-wave (mmWave) communication system performance. At the first step we introduce the mobility model on the example of the pedestrian motion and discuss its parameters for different environments. The impact of mobility on the system performance is estimated by comparison of channel properties vs. mmWave IEEE 802.11ad system parameters...
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...
The ever increasing number of mobile broadband users requires the availability of enhanced data services. Long Term Evolution or LTE is the evolution of High Speed Packet Access (HSPA), which was standardized by third generation partnership project (3GPP) Release 8 in order to meet the increasing demand of faster and more efficient mobile internet access today by supporting the larger bandwidth. This...
The Physical Downlink Shared Channel (PDSCH) is the supreme data-carriage downlink channel in Long Term Evolution (LTE). The PDSCH has Downlink Control Information (DCI) code words of varying length based on the LTE specifications such as DCI format and bandwidth. In this paper, different modules of Transceiver architecture for PDSCH are realized. The PDSCH transmit processing incorporates scrambling,...
This paper designs an underlay control channel for noncontiguous-OFDM-based cognitive networks. Noncontiguous OFDM (NC-OFDM) provides a fast and flexible manner of accessing disjoint parts of the spectrum and is ideally suited for dynamic spectrum access. While similar to OFDM, NC-OFDM explicitly restricts transmission to only certain subcarriers that are free of incumbent transmissions. In particular,...
We consider the resource allocation (RA) optimization problem in shared spectrum access communications system, and propose efficient solutions for both inter-operator and intra-operator RA optimization problems. For inter-operator RA optimization, we present a spectrum sharing framework that primarily focuses on fairness issues for the spectrum sharing operators, by taking care of the sharing policy...
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