The artificial noise (AN) shielded frequency-hopping (FH) architecture can effectively resist wiretapping and electromagnetic interference, but its wide hopping bandwidth will raise a non-negligible in-phase quadrature (IQ) imbalance at transceiver oscillators, yielding significant signal distortions during IQ mixing. Considering this, first, raised by imbalances are modelled in this study, their characteristics mathematically investigated as well. Next, the to distortion-plus-noise ratio...

The orthoimage usually serves as a valuable base layer in GIS. With an increasing demand many urban GIS applications, orthoimages areas are required to represent spatial objects their true positions. However, the traditional methods for generation did not consider features (e.g. occlusion, shadow, etc.) of bridges and buildings), resulting that created cannot be located This paper presents our research experimental results extremely tall using lidar multi-view large-scale aerial images....

In physical layer security, imperfect time synchronization results in random mismatch between the received cooperative jamming (CJ) and reconstructed CJ, leading to performance degradation of CJ cancellation at authorized receiver. this letter, with is analyzed evaluated by ratio (JCR). Then, assuming that timing error uniformly distributed within accuracy, expectation cumulative distribution function (CDF) JCR are provided. Experimental confirm theoretical analysis causes dramatic...

Ambient backscatter (AB) communication enables the devices to modulate and transmit data by reflecting surrounding digital video broadcasting (DVB) signals, has emerged as a promising solution connect low-power small-sized in Internet of Things (IoT). Unfortunately, AB receiver may suffer from strong direct-link interference (DLI) transmitted ambient DVB station, making it difficult decode backscattered signal (BS) directly. In this paper, tackle issue, we propose DLI cancellation method for...

To further protect frequency-hopping (FH) systems against severe wiretapping, an architecture of artificial noise (AN) shielded FH (ANS-FH) is proposed, wherein AN cancellation utilized at the authorized receiver, and secrecy performance analyzed in presence eavesdropper. First, inter-frequency interference (IFI) model employed to depict residual after cancellation. Then, tolerable range frequency deviation given, signal plus ratio (SANR) provided measure performance. Finally, using capacity...

To protect military broadcasting against both hostile interference and eavesdropping, an artificial noise (AN) sheltered frequency hopping (FH) (ANS-FHB) architecture is proposed in this paper, the secrecy capacity employed to measure its performance. Besides, considering inevitable mismatch after synchronization will degrade system practical applications, optimal transmitting power allocation (PA) for confidential information (CI) AN provided maximize presence of mismatch. Moreover, be...

A segmented self-interference cancellation (SSIC) method is proposed for frequency-modulated continuous-wave phased-array radar canceling wideband multipath (SI) signals. radio frequency canceller based on the SSIC that uses time-frequency segmentation equivalence of linear (LFM) signal designed can convert SI (SIC) into several narrowband SICs. Numerical and simulation results show achieve better performance with lower hardware complexity than conventional multi-tap (MTSIC) method....

In single-input multi-output (SIMO) systems, imperfect time alignments result in random mismatch among the signals at receiving antennas, leading to performance degradation of maximum ratio combining (MRC). this letter, by considering timing errors each antenna, closed-form expression output signal-to-noise (SNR) after performing MRC is calculated, and its statistical properties are investigated. Theoretical simulation results show that alignment significantly degrades SNR, especially for...

This paper adopts an artificial noise (AN) shielded frequency hopping (FH) architecture to counteract both wire-tapping and hostile attack, but the inevitable phase will degrade AN cancellation secrecy performance. Considering this, first, performance is analyzed by separating received into cancellable common component (CPC) non-cancellable inter-carrier interference (ICI). On top of system via capacity, degradation for extracted in terms 3 dB coherence bandwidth adopted oscillators,...

Full-duplex technology can effectively alleviate the problem of tight spectrum resources at battlefields, but non-ideal self-interference (SI) cancellation full-duplex nodes worsens signal reception quality. Considering phase noise is major limiting factor SI performance, in this paper, a scenario with independent transceiver oscillators considered, multiple mathematically modelled, distortions for extracted frequency domain, and closed-form expressions signal-to-noise ratios (SNRs) are...

To further enhance the security of wireless communication systems, an architecture cooperative jamming (CJ) assisted slow frequency-hopping (FH) systems is proposed in this paper. Then, after CJ cancellation operation, residual raised from synchronization error analyzed, where inter-symbol interference (ISI) employed to depict time misalignment between received signal and local reference at receiver, inter-hop (IHI) introduced describe frequency misalignment. In addition, closed-form...

In the communication systems employing cooperative jamming (CJ), frequency mismatch will degrade its suppression performance. This paper aims to investigate performance degradation of CJ sheltered hopping (FH) under unknown mismatch. First, system transceiver architecture is detailed illustrated. Then, residual after mathematically depicted, and closed-form expression for ratio (CJSR) provided. Finally, expectation cumulative distribution function (CDF) CJSR are derived measure Theoretical...

In spread spectrum systems, the performance of time synchronization determines communication quality, whereas existing algorithms do not consider impact information symbols' polarity on performance. Besides, despreading operation is carried out at a low signal-to-noise ratio (SNR), and hence it requires number hardware resources for to achieve high-precision synchronization. view this, paper proposes algorithm based correction. Firstly, mathematical model transceivers established. Next,...

In single-input single-output (SISO) systems, transmitting the expected signals with artificially generated noise can effectively enhance physical layer security (PLS). However, traditional suppression at intended receivers will increase algorithm complexity, particularly over multi-path fading channels, which poses challenges for some massive Internet-of-Things (IoT) networks that take advantage of low-cost and resource-constrained nodes. this paper, we design a novel self-noise (SN)...

Full-duplex wireless communication can double the spectral efficiency by transmitting and receiving information simultaneously, but it suffers from strong self-interference (SI). Baseband SI cancellation (SIC) estimate subtract signal, while perfect SIC is unachievable for existence of intended signal. To enhance capability, we propose a two-stage recursive least squares (RLS) filter architecture with low computation complexity environmental robustness. In first stage, acts as traditional...

The early procedures and algorithms for national digital orthophoto generation in the National Digital Orthophoto Program (NDOP) were based on earlier USGS mapping operations, such as field control, aerotriangulation (derived 1920s), quarter-quadrangle-centered (3.75 minutes of longitude latitude geographic extent), 1:40,000 aerial photographs, 2.5 D elevation models. However, large-scale city orthophotos using have disclosed many shortcomings, e.g., ghost image, occlusion, shadow. Thus, to...

Artificial noise (AN) is an effective physical security measure against eavesdropping in wireless communication. In previous literatures, AN generally analyzed multiple transmit antenna systems and suppressed by zero-forcing algorithm, which implemented using the spatial degrees of freedom. this paper, suppression model under single-input multi-output (SIMO) presented, impact imperfect frequency synchronization on performance analyzed. Specifically, we first analyze single branch with...