Voice and Audio Compression for Wireless Communications

Hanzo, Lajos; Somerville, F. Clare; Woodard, Jason

doi:10.1002/9780470516034

Cited by 60 publications

(118 citation statements)

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“…In this section, the attainable performance of the proposed scheme is characterised in terms of BER and Segmental Signal to Noise Ratio (SegSNR) [2] simulation parameters were described in Section 2. In our simulations, a single three-stage "system iteration" is constituted by two inner iterations followed by an outer iteration.…”

Section: Performance Resultsmentioning

confidence: 99%

“…The employment of joint source and channel coding techniques has been motivated by the fact that the classic Shannonian source and channel coding separation theorem [1] has limited applicability in practical speech systems [2]. This is due to the delay-and complexity constraints of practical speech transmission systems.…”

Section: Motivation and Backgroundmentioning

confidence: 99%

“…The AMR-WB speech codec is capable of supporting nine different bit rates [15], each of which may be activated in conjunction with different-rate channel codecs and different-throughput adaptive modem modes [16]. Similar nearinstantaneously adaptive speech and video systems were designed in [2,17]. In our prototype system investigated here the AMR-WB codec operates at 23.05 kbps, generating a set of 52 speech parameters encoded by a total of 461 bits per 20 ms frame for representing the 8 kHz bandwidth speech signal sampled at 16 kHz.…”

Section: Transmittermentioning

confidence: 99%

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Over-Complete Source-Mapping Aided AMR-WB MIMO Transceiver Using Three-Stage Interative Detection

Othman

El‐Hajjar

Pham

et al. 2008

2008 IEEE International Conference on Communications

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-In this paper we propose an iteratively detected Sphere Packing (SP) aided Differential Space-Time Spreading (DSTS) scheme using a Recursive Systematic Convolutional (RSC) code, for protecting the soft-bit assisted Adaptive Multi Rate Wideband (AMR-WB) decoder's bitstream, which is also protected by a novel over-complete source-mapping scheme. The convergence behaviour of the Multiple-Input Multiple-Output (MIMO) transceiver advocated is investigated with the aid of both threedimensional (3D) and two-dimensional (2D) Extrinsic Information Transfer (EXIT) charts. The proposed system exhibits an E b /N0 gain of about 2.5 dB in comparison to the benchmark scheme carrying out iterative source-and channel-decoding as well as DSTS aided SP-demodulation, but dispensing with the over-complete source-mapping, when using I system = 3 system iterations. MOTIVATION AND BACKGROUNDThe employment of joint source and channel coding techniques has been motivated by the fact that the classic Shannonian source and channel coding separation theorem [1] has limited applicability in practical speech systems [2]. This is due to the delay-and complexity constraints of practical speech transmission systems. For example, iterative turbo decoding can be used to exploit the residual redundancy found in the encoded bitstream of finite-delay lossy speech codecs. This residual redundancy is inherently present owing to the limitedcomplexity, limited-delay source encoders' failure to remove all the redundancy from the correlated speech source signal.Vary and his team [3,4] developed the concept of soft speech bits exploiting the residual redundancy. Their work culminated in the formulation of iterative source and channel decoding (ISCD) [5]. More explicitly, in order to improve the overall system performance, extrinsic information is exchanged between the constituent decoders including the source decoder. As a further development, in [6] and [7] the inherent residual redundancy of the encoded bitstream was deliberately increased using redundant index assignments and multi-dimensional mapping schemes, which resulted in an enhanced soft-bit source decoder performance.In [6], the iterative decoding behaviour of an ISCD scheme was studied using Extrinsic Information Transfer (EXIT) charts [8], for characterizing the achievable performance of the ISCD scheme exploiting the residual redundancy inherent in the source encoded bitstream. In this contribution we propose and investigate the jointly optimised ISCD scheme of Figure 1 by using the novel Over-Complete source-Mapping (OCM) of [10], which is protected by a Recursive Systematic Convolutional (RSC) code. The resultant bitstream is transmitted using Differential SpaceTime Spreading (DSTS) combined with Sphere Packing (SP) modulation [11] over a temporally correlated narrowband Rayleigh fading channel. More explicitly, in the resultant multi-stage scheme extrinsic information is exchanged amongst the three constituent decoders, namely the source decoder, the channel decoder and the DSTS-...

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Section: Performance Resultsmentioning

confidence: 99%

Section: Motivation and Backgroundmentioning

confidence: 99%

Section: Transmittermentioning

confidence: 99%

See 1 more Smart Citation

Over-Complete Source-Mapping Aided AMR-WB MIMO Transceiver Using Three-Stage Interative Detection

Othman

El‐Hajjar

Pham

et al. 2008

2008 IEEE International Conference on Communications

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“…By determining the total distortion D as a sum of the inner distortion D i (11) and the outer distortion D o (21), the signal to quantization noise ratio can be determined [Jayant and Noll, 1984;Hanzo et al, 2007]:…”

Section: Design Of Novel Piecewise Uniform Scalar Quantizermentioning

confidence: 99%

“…The common approach to solving constrained optimization problems is based on the method of Lagrange multipliers [Jayant and Noll, 1984;Hanzo et al, 2007]. This method converts the constrained optimization problem:…”

Section: Design Of Novel Piecewise Uniform Scalar Quantizermentioning

confidence: 99%

Design of novel piecewise uniform scalar quantizer for Gaussian memoryless source

Velimirović¹,

Perić²,

Nikolić³

2012

Radio Science

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[1] In this paper we propose a novel piecewise uniform scalar quantizer model designed for a Gaussian memoryless source. The segment thresholds of this quantizer model are equidistant while the number of reproduction levels inside segments is determined by optimizing the inner distortion and under the constraint of total number of reproduction levels. For the proposed quantizer model the quantization efficiency and signal to quantization noise ratio (SQNR) is studied. On the basis of the comparison with the efficiency and SQNR of uniform quantizer advantages of the proposed quantizer model are shown. Particularly, it is shown that with the proposed quantizer the correlation between the input signal and the quantization error can be eliminated more than by using the uniform quantizer as well as that the proposed quantizer provides higher level of SQNR.Citation: Velimirović, L., Z. Perić, and J. Nikolić (2012), Design of novel piecewise uniform scalar quantizer for Gaussian memoryless source, Radio Sci., 47, RS2005,

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