Variable Length Coding

The new video coding standard, H.264/MPEG-4 AV C, uses an intra prediction mode with 4x4 blocks and 16x16 blocks sizes for luma component and 8x8 blocks size for chroma component. This new feature of H.264/AVC offers a considerably higher improvement in coding efficiency compared to other compression standards. In order to achieve this, a robust Rate-distortion optimization (RDO) technique is employed to select the best coding mode for each block sizes. However, the computational complexity of H.264 encoder is drastically increased due to the various intra prediction modes. In this paper, we propose a fast mode decision algorithm for intra prediction to reduce the complexity of H.264 video coding. The proposed algorithm based the fact that the dominating direction of a smaller block is similar to that of bigger block, the directional correlation of each block is consistent with directions of the edges, and the prediction modes of each block are also correlated with those of neighboring modes. The experimental results show that the fast intra mode decision algorithm is able to reduce on the average 84.68% encoding time, with a negligible peak signal-to noise ratio loss of 0.19dB or, equivalently, a bit rate increment of 1.88%.

Serially concatenated and iteratively decoded Irregular Variable Length Coding (IrVLC) combined with precoded Fast Frequency Hopping (FFH) M-ary Frequency Shift Keying (MFSK) is considered. We employ EXtrinsic Information Transfer (EXIT) charts to investigate the 3-stage concatenation of the FFH-MFSK demodulator, the rate-1 decoder and the outer IrVLC decoder. The proposed joint source and channel coding scheme is capable of operating at low Signal-to-Noise Ratio (SNR) in Rayleigh fading channels contaminated by Partial Band Noise Jamming (PBNJ). The IrVLC scheme is comprised of a number of component Variable Length Coding (VLC) codebooks employing different coding rates for encoding particular fractions of the input source symbol stream. These fractions may be chosen with the aid of EXIT charts in order to shape the inverted EXIT curve of the IrVLC codec so that it can be matched with the EXIT curve of the inner decoder. We demonstrate that using the proposed scheme an infinitesimally low bit error ratio may be achieved at low SNR values.

Serially concatenated and iteratively decoded Irregular Variable Length Coding (IrVLC) combined with precoded Fast Frequency Hopping (FFH) M -ary Frequency Shift Keying (MFSK) is considered. We employ EXtrinsic Information Transfer (EXIT) charts to investigate the 3-stage concatenation of the FFH-MFSK demodulator, the rate-1 decoder and the outer IrVLC decoder. The proposed joint source and channel coding scheme is capable of operating at low Signal-to-Noise Ratio (SNR) in Rayleigh fading channels contaminated by Partial Band Noise Jamming (PBNJ). The IrVLC scheme is comprised of a number of component Variable Length Coding (VLC) codebooks employing different coding rates for encoding particular fractions of the input source symbol stream. These fractions may be chosen with the aid of EXIT charts in order to shape the inverted EXIT curve of the IrVLC codec so that it can be matched with the EXIT curve of the inner decoder. We demonstrate that using the proposed scheme an infinitesimally low bit error ratio may be achieved at low SNR values.

Serially concatenated and iteratively decoded Irregular Variable Length Coding (IrVLC) combined with precoded Fast Frequency Hopping (FFH) M-ary Frequency Shift Keying (MFSK) is considered. We employ EXtrinsic Information Transfer (EXIT) charts to investigate the 3-stage concatenation of the FFH-MFSK demodulator, the rate-1 decoder and the outer IrVLC decoder. The proposed joint source and channel coding scheme is capable of operating at low Signal-to-Noise Ratio (SNR) in Rayleigh fading channels contaminated by Partial Band Noise Jamming (PBNJ). The IrVLC scheme is comprised of a number of component Variable Length Coding (VLC) codebooks employing different coding rates for encoding particular fractions of the input source symbol stream. These fractions may be chosen with the aid of EXIT charts in order to shape the inverted EXIT curve of the IrVLC codec so that it can be matched with the EXIT curve of the inner decoder. We demonstrate that using the proposed scheme an infinitesimally low bit error ratio may be achieved at low SNR values.

To achieve the best coding efficiency, H.264 encoder has to evaluate exhaustively all the mode combinations of intra and inter predictions for deciding coding mode. The computational complexity and time taken for deciding modes and encoding are more than any other previous standards. The RD-Cost based mode decision is used generally, which will consume more time and has more computational complexity. Estimation of bitlength (rate) based on Context based Adaptive Variable Length Coding (CAVLC) and Exp-Golomb Coding tables is proposed during RD-cost calculation avoiding real entropy encoding. The experimental results demonstrate that proposed method reduces at least 40% of computation complexity without compromising the coding efficiency and performance.

In this contribution, we propose two successive
interference cancellation (SIC) schemes for a fast frequency
hopping (FFH) multiple access (MA) system using M-ary frequency
shift keying (MFSK) and invoking multi-user detection
(MUD). One of the proposed schemes invokes clipped combining,
while the other scheme employs both product combining and
clipped combining. The SIC schemes are adapted from a scheme
proposed by U.-C. Fiebig in 1996. The basic principle of the SIC
schemes is that detection is carried out in multiple stages and
during each stage, only the most reliable symbols are detected.
In subsequent stages, the interference contributed by the already
detected symbols may be removed. The performance of the
proposed schemes is evaluated and compared to that of Fiebig’s
scheme, when the FFH-MFSK system operates in a Nakagamim
fading MA channel. The simulation results demonstrate that
the proposed schemes attain a better bit error rate performance
than Fiebig’s scheme.

Serially concatenated and iteratively decoded Irregular
Variable Length Coding (IrVLC) combined with precoded
Fast Frequency Hopping (FFH) M-ary Frequency Shift Keying
(MFSK) is considered. We employ EXtrinsic Information
Transfer (EXIT) charts to investigate the 3-stage concatenation
of the FFH-MFSK demodulator, the rate-1 decoder and the outer
IrVLC decoder. The proposed joint source and channel coding
scheme is capable of operating at low Signal-to-Noise Ratio
(SNR) in Rayleigh fading channels contaminated by Partial Band
Noise Jamming (PBNJ). The IrVLC scheme is comprised of a
number of component Variable Length Coding (VLC) codebooks
employing different coding rates for encoding particular fractions
of the input source symbol stream. These fractions may be chosen
with the aid of EXIT charts in order to shape the inverted EXIT
curve of the IrVLC codec so that it can be matched with the
EXIT curve of the inner decoder. We demonstrate that using the
proposed scheme an infinitesimally low bit error ratio may be
achieved at low SNR values.

—Iterative decoding of an irregular variable-length coding (IrVLC) scheme concatenated with precoded fast frequency-hopping (FFH) M-ary frequency-shift keying (MFSK) is considered. We employ EXtrinsic Information Transfer (EXIT) charts to investigate the three-stage concatenation of the FFH-MFSK demodulator, the rate-1 decoder, and the outer IrVLC decoder. The proposed joint source and channel coding scheme is capable of operating at low signal-to-noise ratios (SNRs) in Rayleigh fading channels contaminated by partial-band noise jamming (PBNJ). The IrVLC scheme is composed of a number of component variable-length coding (VLC) codebooks employing different coding rates that encode particular fractions of the input source symbol stream. These fractions may be chosen with the aid of EXIT charts to shape the inverted EXIT curve of the IrVLC codec so that it can be matched with the EXIT curve of the inner decoder. We demonstrate that using the proposed scheme, an infinitesimally low bit error ratio (BER) may be achieved at low SNR values. Index Terms—FEC, irregular channel coding, iterative detection of fast frequency-hopping (FFH) M-ary frequency-shift keying (MFSK), turbo-detection, unity-rate coding, variable-length coding (VLC).

Serially concatenated and iteratively decoded Irregular Variable Length Coding (IrVLC) combined with precoded Fast Frequency Hopping (FFH) M -ary Frequency Shift Keying (MFSK) is considered. The proposed joint source and channel coding scheme is capable of low Signal-to-Noise Ratio (SNR) operation in Rayleigh fading channels contaminated by Partial Band Noise Jamming (PBNJ). The IrVLC scheme is comprised of a number of component Variable Length Coding (VLC) codebooks employing different coding rates for encoding particular fractions of the input source symbol stream. These fractions may be chosen with the aid of EXtrinsic Information Transfer (EXIT)