Robust multiple description distributed video coding using optimized zero-padding

Distributed video coding （DVC） arouses high interests due to its property of low-complexity encoding. This paper proposes a robust multiple description DVC （MDDVC） under the constraint of low-complexity encoding. In MDDVC, zeros are padded to each frame and the resulting big-size video is divided into multiple descriptions. Then, each description is compressed by s hybrid DVC （HDVC） codec and trans- mitted over different channel. When one channel does not work, the lost HDVC description is estimated by the received from other channel, which guarantees the robustness of the system; MDDVC moves the complex motion estimation totally to the decoder so it features low-complexity encoding. In the pre-processing, an optimized zero-padding is also proposed to improve the performance. Experimental results exhibit that the proposed MDDVC scheme achieves better rate-distortion performance and robustness than the referenced especially when packet-loss rate is high.

A block zero-padding method based on DCFT for L1 parameter estimations in weak signal and high dynamic environments

Weak L1 signal acquisition in a high dynamic environment primarily faces a challenge： the integration peak is neg- atively influenced by the possible bit sign reversal every 20 ms and the frequency error. The block accumulating semi-coherent integration of correlations （BASIC） is a state-of-the-art method, but calculating the inter-block conjugate products restricts BASIC in a low signal-to-noise ratio （SNR） acquisition. We propose a block zero-padding method based on a discrete chirp-Fourier transform （DCFT） for parameter estimations in weak signal and high dynamic environments. Compared with the conventional receiver architecture that uses closed-loop acquisition and tracking, it is more suitable for open-loop acquisition. The proposed method combines DCFT and block zero-padding. In this way, the post-correlation signal is coherently post-integrated with the bit sequence stripped off, and the high dynamic parameters are precisely estimated using the threshold set based on a false alarm probability. In addition, the detection performance of the proposed method is analyzed. Simulation results show that compared with the BASIC method, the proposed method can precisely detect the high dynamic parameters in lower SNR when the length of the received signal is fixed.

Edge Effect Correction in the S-A Method for Geochemical Anomaly Separation

Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and holes (with missing data) often causes frequency distribution distortion in the frequency domain. For example, bright strips are commonly seen in frequency distribution when using a Fourier transform. Such edge effect distortion may affect information extraction results; sometimes severely, depending on the edge abruptness of the image. Traditionally, edge effects are reduced by smoothing the image boundary prior to applying a Fourier transform. Zero-padding is one of the most commonly used smoothing methods. This simple method can reduce the edge effect to some degree but still distorts the image in some cases. Moreover, due to the complexity of geoscience images, which can include irregular shapes and holes with missing data, zero-padding does not always give satisfactory results. This paper proposes the use of decay functions to handle edge effects when extracting information from geoscience images. As an application, this method has been used in a newly developed multifractal method (S-A) for separating geochemical anomalies from background patterns. A geochemical dataset chosen from a mineral district in Nova Scotia, Canada was used to validate the method.

ZP-CI/OFDM:A Power Efficient Wireless Transmission Technology

Low power efficiency is a deficiency in traditional Orthogonal Frequency Division Multiplexing （OFDM） systems. To counter this problem, a new wireless transmission technology based on Zero-Padding Carrier Interferometry OFDM （ZP-CI/OFDM） is proposed. In a ZP-CI/OFDM system, transmission symbols are spread to all OFDM subcarriers via carrier interferometry codes. This reduces the Peak-to-Average Power Ratio （PAPR） that traditional OFDM suffers and also exploits frequency diversity gain. By zero-padding at the transmitter, advanced receiver technologies can be adopted for ZP-CI/OFDM so that frequency diversity gain can be further utilized and the power efficiency of the system is improved.