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Channel coding for progressive images in a 2-D time-frequency OFDM block with channel estimation errors.

Toni, L; Chan, YS; Cosman, PC; Milstein, LB; (2009) Channel coding for progressive images in a 2-D time-frequency OFDM block with channel estimation errors. IEEE Trans Image Process , 18 (11) pp. 2476-2490. 10.1109/TIP.2009.2026676. Green open access

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Abstract

Coding and diversity are very effective techniques for improving transmission reliability in a mobile wireless environment. The use of diversity is particularly important for multimedia communications over fading channels. In this work, we study the transmission of progressive image bitstreams using channel coding in a 2-D time-frequency resource block in an OFDM network, employing time and frequency diversities simultaneously. In particular, in the frequency domain, based on the order of diversity and the correlation of individual subcarriers, we construct symmetric n -channel FEC-based multiple descriptions using channel erasure codes combined with embedded image coding. In the time domain, a concatenation of RCPC codes and CRC codes is employed to protect individual descriptions. We consider the physical channel conditions arising from various coherence bandwidths and coherence times, leading to a range of orders of diversities available in the time and frequency domains. We investigate the effects of different error patterns on the delivered image quality due to various fade rates. We also study the tradeoffs and compare the relative effectiveness associated with the use of erasure codes in the frequency domain and convolutional codes in the time domain under different physical environments. Both the effects of intercarrier interference and channel estimation errors are included in our study. Specifically, the effects of channel estimation errors, frequency selectivity and the rate of the channel variations are taken into consideration for the construction of the 2-D time-frequency block. We provide results showing the gain that the proposed model achieves compared to a system without temporal coding. In one example, for a system experiencing flat fading, low Doppler, and imperfect CSI, we find that the increase in PSNR compared to a system without time diversity is as much as 9.4 dB.

Type: Article
Title: Channel coding for progressive images in a 2-D time-frequency OFDM block with channel estimation errors.
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1109/TIP.2009.2026676
Publisher version: https://doi.org/10.1109/TIP.2009.2026676
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: OFDM modulation;channel coding;channel estimation;convolutional codes;cyclic redundancy check codes;diversity reception;image coding;intercarrier interference;mobile radio;multimedia communication;time-frequency analysis;CRC code;OFDM network;RCPC code;channel coding;channel erasure code;channel estimation error;channel variation;convolutional code;fading channel;frequency diversity;frequency domain code;frequency selectivity;image coding;image quality;intercarrier interference;mobile wireless environment;multimedia communication;n-channel FEC;progressive image bitstream transmission;time diversity;time-frequency OFDM;Channel coding;cross-layer design;diversity;multimedia communications;multiple description coding;orthogonal frequency division multiplexing (OFDM);progressive transmission;wireless video
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng
URI: https://discovery.ucl.ac.uk/id/eprint/1533114
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