The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper proposes a new algorithm for missile-borne SAR which has acceleration and velocity for vertical dimension, side dimension and azimuth dimension. The 3-dimension acceleration results in stronger coupling between range and azimuth signal which makes missile-borne SAR imaging more difficult. The algorithm decreases the coupling with range walk correction in range frequency domain, azimuth...
Abstract-As we know, SC-FDMA has been adopted as the uplink access technique in 3GPP LTE standard due to its low PAPR. However, PAPR is still an issue for SC-FDMA, especially with the localized subcarrier allocation scheme. In this paper, we propose a new SLM method with feedback searching, where, ZC (Zandoff-chu) sequence is considered as the initial phase rotation factor, and feedback searching...
Cooperative relaying has played an important role in the rapid evolution of wireless communications. The cooperative performance strongly depends on the selected relays. In this paper, an improved Least Maximum Pathloss (LMP) method is analyzed for the relay node selection. Both the direct transmission as well as the traditional LMP and the improved LMP under the condition of cooperative amplify-and-forward...
In a wireless network, multi-user diversity can be employed to improve system throughput performance by scheduling the channel to the user with the best instantaneous channel state information (CSI). However, the overhead induced by polling CSIs of a large number of users can overshadow the multi-user diversity gain. In our previous work, a user identification approach (UIDA) was proposed to reduce...
Circular SAR (CSAR) can obtain images of high resolution. However, the image quality is very sensible to sub-wavelength motion errors caused by platform position uncertainty. Due to the limit of accuracy of the inertial measurement units (IMU) systems, a robust autofocus technique has to be used to cope with the demands of CSAR image formation. Because of the serious coupling between range and azimuth,...
Visual Computational Theory that was founded by Marr plays an extraordinarily important role in Visual Science. There is still lot of research to do for this theory, such as building it in spatial frequency domain. Our research will be mainly on Visual Computational theory in spatial frequency domain and an application of the theory, which is the simulation of dynamic radiated fringes.
In this paper, we propose a scheme of waveforms for cognitive ultra-wideband radio transmission, based on Gaussian pulses, where the influences of performance parameters of Gaussian base pulse including the differential orders and shaping factors on the transmission waveform spectrum are discussed, and then a scheme of generating combinative waveforms based on Gaussian derivative function pulses is...
In this thesis, the statistical characteristics of ship-radiated noise are discussed. Then, a mathematical model of the noise reconstruction is established for given sea depth and straight distance. The model includes the main characteristics of ship-radiated broadband noise: the continuous power spectrum, the line spectrum, the envelope spectrum, the total radiated sound power and the sound level...
There are many abstract concepts and mathematic theory in electron information specialty which are difficult to understand. Experimentation is the necessary part of teaching process. Simulation analysis of SystemView can renovate experiment contents expediently. This paper discusses the application of SystemView in experiment teaching of electron information specialty. The practice shows that the...
A key aspect of a previously proposed undersampled digitally heterodyned stepped frequency GPR is the capability to generate and acquire a large band of frequencies. This is obtained by moving most of the analog domain functionalities of the SFGPR into the digital one. In this paper an analysis of the aliased images generated by the digital frequency generator is performed. Its necessity is dictated...
This paper presents a new time-domain design procedure for three-stage amplifiers with reversed nested Miller compensation (RNMC). By utilizing this method, the values of the compensation capacitors are properly selected to achieve the best settling time. To demonstrate the effectiveness of the proposed method, a three-stage amplifier is designed and simulated in a 1V, 90nm CMOS technology. Simulation...
In Single carrier system with frequency domain equalization (SC-FDE) equalization is playing a crucial role for the system performance. A simple equalization scheme is proposed for precoding SC-FDE. This scheme doesn't need complex computation and is easy to implement. Simulations are used to demonstrate the performance of the scheme.
The concept of using unique word (UW) prefixes instead of cyclic prefixes (CPs) is already well investigated for single carrier systems with frequency domain equalization (SC/FDE). In OFDM (orthogonal frequency division multiplexing), where the data symbols are specified in frequency domain, the introduction of UWs - which are specified in time domain - is not that straight forward. In this paper...
A semi-blind equalization method is proposed for precoding single carrier system with frequency domain equalization(SC-FDE). The method is modified according to Bussgang algorithm and the implementation is easy because it does not need complex computation. Simulations are used to demonstrate the proposed method.
Single-carrier frequency division multiple access (SC-FDMA) with iterative multiuser detection, called grouped FDMA (GFDMA), allows several users to share a common set of subcarriers. In order to improve user fairness and guarantee quality-of-service (QoS) of users who share subcarrier sets, we propose a proportional fair (PF) scheduling algorithm satisfying QoS constraints. For each user selection...
Single carrier frequency division multiple access (SC-FDMA), which combines the single carrier frequency domain equalization (SC-FDE) and frequency division multiple access (FDMA) techniques is a promising broadband wireless access scheme. However, previous research has shown that the peak-to-average power ratio (PAPR) of SC-FDMA is high especially in the case of localized subcarrier mapping. In this...
A novel method to simulate the FIR filter based on GUI(Graphic User Interface) is introduced in this paper. This method not only depended on Matlab code, but also made use of controls which generate a GUI. All the operations have been done by GUI. This paper took window-function method to realize FIR filter for example to design digital low-pass, high-pass and band-pass filters. The simulation results...
Rapid development of wireless communications gives prominence to simulation. Simulated methods of modeling wireless channel are of significance to wireless communications simulation on both link and system levels. There have been quite a lot of theoretical models which have accurately described the characteristics of wireless channel. However when it comes to the realization of wireless channel in...
Conventional polarization filters can mitigate an interference by using the orthogonal vector of the interference polarization, but leading to distortion of the target signal in its amplitude and phase. A null phase-shifting polarization filter can reconstruct the original target signal. However, it needs some complex operations, such as a linear polarization-vector translation and compensations in...
This paper presents the novel multi-bit bitwise adaptive embedding algorithms for data hiding. These embedding algorithms can embed multi-bit (k-bit, k ≥ 1 ) secret data into cover data only introduce minimum embedding error smaller than (2k-1-1)2i-k according to the embedding location i. To achieve such a goal, the proposed embedding algorithm adaptively evaluates the most similar value to replace...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.