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IEEE International Symposium on Intelligent Control

作者： Terki, N Doghmane, N Terki, A Univ Annaba Dept Elect Annaba Algeria

ISBN: (纸本)078037620X

In this paper we introduce a compression algorithm using wavelet transform.. The principle of wavelet transform is to decompose hierarchically the input image into a series of successively lower resolution reference images and detail images that contain the information needed to be reconstructed back to the next higher resolution level. The histogram of image sub bands;provide us with information on the distribution of the coefficient values in this sub image. The sub band images resulting from wavelet transform are not equal significance. Some sub bands contain more information than others. The total number of available bits describe an image is however, inevitably limited. Therefore, it is desirable to allocate more bits to those sub band images and can be coded more accurately than others. The objective of such bit allocation method is to optimize the overall coder performance and minimize the quantization error. In determining which wavelet filter is to be used for image compression, some of the properties considered are:- vanishing moments;the phase nonlinearity of the filter can cause sever degradation in the subjective quality of an image. It is related to the symmetry of the filter coefficients. The wavelet transform is implemented using a linear-phase biorthogonal filter(16,4) with 4 level of decomposition. For this study, we used a scalar quantization with uniform threshold quantizers. The quantization method is PCM (pulse code modelation) for the coefficients in all high-pass sub bands. The coefficients of low-pass sub band are DPCM (Differential PCM) quantized per region.

关键词： image compression daubechies fillters biorthogonal wavelet bit allocation algorithm quantization

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Two-stage bit allocation algorithm for stereo audio coder

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IEE PROCEEDINGS-VISION IMAGE AND SIGNAL PROCESSING 1996年第5期143卷 331-336页

作者： Jean, FR Long, CF Hwang, TH Wang, HC NATL TSING HUA UNIV DEPT ELECT ENGNHSINCHU 30043TAIWAN

A new bit allocation algorithm is proposed and applied in a stereo transform coder. This algorithm is a two-stage approach based on the minimisation of perceptual distortion measured by artificial ears. At the first stage, the use of minimum frequency-weighted reconstruction error is exploited, in which the weighting factors are related to the masking threshold and the absolute hearing threshold. The bit assignment obtained at the first stage is fine tuned by a greedy algorithm of perceptual distortion versus bit rate at the second stage. A joint stereo perceptual transform coder is implemented and incorporated with this two-stage bit allocation algorithm. The listening tests show that this coder performs better than MPEG layer 2 at bit rates below 128 kbps and has the comparative quality of MPEC layer 2 at higher bit rates.

关键词： bit allocation algorithm stereo transform coder

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Efficient bit allocation algorithm for ISO/MPEG audio encoder

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ELECTRONICS LETTERS 1998年第8期34卷 721-722页

作者： Teh, DH Koh, SN Tan, AP Nanyang Technol Univ Sch Elect & Elect Engn Singapore 2263 Singapore Panason Singapore Labs Pte Ltd Singapore Singapore

An efficient bit allocation algorithm for the ISO/MPEG audio layer 2 encoder is proposed. The resulting encoder is able to produce an ISO/MPEG compliant bit stream which is almost identical to the bit stream produced by the reference ISO/MPEG encoder suggested in IS 11172-3. More importantly, the number of computational steps is greatly reduced as compared to the method recommended by the ISO/MPEG Committee because the efficient bit allocation algorithm significantly reduces the number of iterations required. It was found that the efficient bit allocation algorithm works best when the bit rate demanded by the psychoacoustic model in order to keep the quantisation noise below the masking threshold is almost equal to the operational bit rate.

关键词： ISO/MPEG audio encoder telecommunication standards operational bit rate audio coding data compression ISO standards bit allocation algorithm masking threshold quantisation noise ISO/MPEG compliant bit stream Codes quantisation (signal) computational steps reduction Audio equipment and systems Signal processing and detection 96 kbit/s psychoacoustic model

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Low-complexity energy-efficient resource allocation for delay-tolerant two-way orthogonal frequency-division multiplexing relays

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IET COMMUNICATIONS 2016年第17期10卷 2488-2495页

作者： Yu, Tiantian Jin, Yanliang Guo, Weisi Fang, Changli Deng, Wei Wang, Tao Shanghai Univ Sch Commun & Informat Engn Shanghai Peoples R China Univ Warwick Sch Engn Coventry W Midlands England

Energy-efficient wireless communication is important for wireless devices with a limited battery life and cannot be recharged. In this study, a bit allocation algorithm to minimise the total energy consumption for transmitting a bit successfully is proposed for a two-way orthogonal frequency-division multiplexing relay system, whilst considering the constraints of quality-of-service and total transmit power. Unlike existing bit allocation schemes, which maximise the energy efficiency (EE) by measuring bits-per-Joule' with fixed bidirectional total bit rates constraint and no power limitation, their scheme adapts the bidirectional total bit rates and their allocation on each subcarrier with a total transmit power constraint. To do so, they propose an idea to decompose the optimisation problem. The problem is solved in two general steps. The first step allocates the bit rates on each subcarrier when the total bit rate of each user is fixed. In the second step, the Lagrangian multipliers are used as the optimisation variants, and the dimension of the variant optimisation is reduced from 2N to 2, where N is the number of subcarriers. They also prove that the optimal point is on the bounds of the feasible region, thus the optimal solution could be searched through the bounds.

关键词： relay networks (telecommunication) OFDM modulation optimisation low-complexity energy-efficient resource allocation delay-tolerant two-way orthogonal frequency-division multiplexing relays system energy-efficient wireless communication bit allocation algorithm M2M communications spectral efficiency EE variant optimisation Lagrangian multipliers Internet-of-things

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An efficient data rate maximization algorithm for OFDM based wireless networks

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WIRELESS NETWORKS 2010年第1期16卷 17-25页

作者： Ilic, Zeljko Bazant, Alen Modlic, Borivoj Univ Zagreb Fac Elect Engn & Comp Zagreb 10000 Croatia

In this paper we present a computationally efficient, suboptimal integer bit allocation algorithm that maximizes the overall data rate in multiuser orthogonal frequency division multiplexing (OFDM) systems implemented in wireless networks Assuming the complete knowledge of a channel and allowing a subchannel to be simultaneously shared by multiple users we have solved this data rate maximization problem in two steps The first step provides subchannel assignment to users considering the users. requests on quality of service (QoS) expressed as the minimum signal-to-noise ratio (SNR) on each subchannel. The second step provides transmit power and bit allocation to subchannels in order to maximize the overall data rate To reduce computational complexity of the problem we propose a simple method which assigns subchannels to users and distributes power and bits among them We have analyzed the performance of our proposed algorithm simulation ill a multiuser frequency selective fading environment for various signal-to-noise ratios and Various numbers of users in the system. We have Concluded that our algorithm, unlike other similar algorithms, is Suitable for OFDM wireless networks, especially when signal-to-noise ratio in the channel is low. Also, the results have shown that the total data rate grows with the number of users in the system

关键词： Wireless networks Multiuser OFDM system bit allocation algorithm Power allocation algorithm QoS

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Efficient audio coding with optimized subband configurations

Efficient audio coding with optimized subband configurations

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Workshop on Applications of Signal Processing to Audio and Acoustics

作者： Ali, MT Mian, MS Univ Engn & Technol Dept Elect Engn Lahore Pakistan

ISBN: (纸本)0780391543

A dynamic subbands design selection scheme for perceptual audio coding is presented which optimizes the coding efficiency in association with all improved utilization of the masking potential of the signal. The choices for subbands design Selection include critical hands, uniform subbands, uniform subbands with a non-uniform last hand and a non-uniform-non-critical (NUNC) subbands distribution. A particular consideration is given to corresponding critical band boundaries while formulating NUNC subbands, to minimize the perception of coding noise. The design selection decision is made by First identifying the best tradeoff between empty quantizer slots and amount of side information, followed by a minimization or the perceptual entropy (PE) estimates. A further analysis is carried Out to identify the prominent spectral peaks (PSPs), with a view to efficiently utilize their masking potential by the bit allocation algorithm which makes a bit cut first to subbands with PSPs. Test results based oil ITU-R recommendation BS.1 116 show that Our coding scheme performs slightly better as compared to MPEG-4 AAC verification model (V-M) for a majority of signal types from the SQAM database. The paper Concludes with a discussion Of future research implications of the work.

关键词： audio coding entropy ITU-R recommendation BS.1116 MPEG-4 AAC verification model SQAM database bit allocation algorithm coding efficiency coding noise critical bands dynamic subbands design selection scheme nonuniform last band nonuniform-noncritical subb Audio coding Subbands allocation algorithm critical band entropy code efficiency side information

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