Купить СНПЧ А7 Архангельск, оперативня доставка

Transmissão de Imagens e Sinais de Voz Quantizados Vetorialmente em Canais com Desvanecimento

DOI: http://dx.doi.org/10.12702/DW-000000001

 downloadpdf

LOPES, Waslon Terllizzie Araújo

 

Resumo: A quantização vetorial tem sido bastante estudada para aplicações envolvendo sinais de voz e imagens, permitindo altas taxas de compressão. Contudo, os dados provenientes da quantização vetorial são bastantes sensíveis aos erros introduzidos pelo canal de comunicações. Neste trabalho, o desempenho de um sistema de comunicações, baseado na quantização vetorial, é avaliado sob o ponto de vista da transmissão através de canais com desvanecimento. A transmissão por intermédio de múltiplas antenas transmissoras também é analisada. Duas técnicas, que não aumentam a complexidade do sistema, são apresentadas para a melhoria de desempenho. A primeira se baseia na rotação da constelação de sinais transmitidos e no entrelaçamento das transmissões. A segunda consiste na organização do dicionário para quantização vetorial com o objetivo de minimizar os efeitos provocados por erros no canal. A avaliação das técnicas apresentadas é feita por meio de simulações da transmissão de sinais de voz e imagens.

 

Abstract: Vector quantization has been widely studied in connection with problems of signal and image compression, allowing high compression ratios. On the other hand, the data signal produced by the vector quantizer is very sensitive to errors introduced by the communication channel. In this work, the performance of a communication system, based on vector quantization, is evaluated, considering the transmission over a fading channel. The transmission using multiple antennas is also analyzed. Two techniques, which do not increase the system complexity, are presented to improve the system performance. The first is based on rotating the transmitted signal constellation and interleaving. The second consists in organizing the vector quantizer dictionary, in order to minimize the effect of errors in the signal to noise ratio. The evaluation of the cited techniques involves simulating the transmission of voice signals and images.

 

Literatura Citada

[1] “Special Issue on the European Path Towards UMTS”, IEEE Personal Commun. Mag., Feb 1995. 

[2] A. F. Naguib, V. Tarokh, N. Seshadri and A. R. Calderbank. “A Space-Time Coding Modem for High-Data-Rate Wireless Communications”. IEEE Journal on Selected Areas in Communications, 16(8):1459–1478, October 1998. doi

[3] A. Gersho. “On the Strucuture of Vector Quantizers”. IEEE Transactions on Information Theory, 28:157–166, March 1982. doi

[4] A. Gersho and R. M. Gray. “Vector Quantization and Signal Compression”. Kluwer Academic Publishers, Boston, MA, 1992. doi

[5] A. Lau and F. R. Kschischang. “A Sequential Soft-Decision Decoder for Reed-Solomon Codes Aplied to Encoded PSK in Rayleigh Fading Channels”. IEEE Transactions on Vehicular Technology, 45(1):97–104, February 1996. doi

[6] A. Lowry, H. Sqama and W. Millar. “Binary Search Trees for Vector Quantization”. Proc. ICASSP’87, 4:2205–2208, April 1987. 

[7] M. S. Alencar. “Comunicações Móveis Celulares”. Apostila, Universidade Federal da Paraíba, 1998. 

[8] M. R. Anderberg. “Cluster Analysis for Applications”. Academic Press, New York, NY, 1973. 

[9] B. D. Jelicic and S. Roy. “Design of Trellis Coded QAM for Flat Fading and AWGN Channels”. IEEE Transactions on Vehicular Technology, 44:192–201, February 1995. doi

[10] C. Leung L. Chan. “Transmission of Vector Quantized Data over a Noisy Channel”. IEEE Transactions on Neural Networks, 8(3):582–589, May 1997. doi

[11] H. Abut. “Vector Quantization”. IEEE Press, New York, 1990. 

[12] D. Divsalar and M. K. Simon. “The Design of Trellis Coded MPSK for Fading Channels: Performance Criteria”. IEEE Transactions on Communications, 36(9):1004–1012, 1988. doi

[13] E. Zehavi. “8-PSK Trellis Codes for a Rayleigh Channel”. IEEE Transactions on Communications, 40:873–884, May 1992. doi

[14] P. Elias. “Coding for Noisy Channels”. IRE Conv. Record, Part 4, pages 37–44, 1955. 

[15] R. M. Fano. “A Heuristic Discussion of Probabilistic Decoding”. IEEE Transactions on Information Theory, pages 64–74, April 1963. doi

[16] G. D. Forney Jr. “The Viterbi Algorithm”. Proceedings of the IEEE, 61:268–278, March 1973. doi

[17] G. D. Forney Jr. “Geometrically Uniform Codes”. IEEE Transactions on Information Theory, 37:1241–1260, 1991. doi

[18] G. J. Foschini and M. J. Gans. “On Limits of Wireless Communications in a Fading Environment When Using Multiple Antennas”. Wireless Personal Communications, 6(3):311, March 1998. doi

[19] J. C. Guey, M. P. Fitz, M. R. Bell and W. Y. Kuo. “Signal Design for Transmitter Diversity Wireless Communication Systems over Rayleigh Fading Channels”. Proceedings of the IEEE 46th Vehicular Technology Conference – VTC’96, pages 136–140, 1996. 

[20] J. Makhoul, S. Roucos and H. Gish. “Vector Quantization in Speech Coding”. Proceedings of the IEEE, 73:1551–1558, November 1985. doi

[21] F. Jelinek. “A Fast Sequential Decoding Algorithm Using a Stack”. IBM Journal of Research and Development, 13:675–685, November 1969. doi

[22] F. M. Bernadino Jr. “Quantização Vetorial Aplicada à Compressão de Sinais de Voz e Imagem”. Dissertação de mestrado, Universidade Federal da Paraíba, Março 1998. 

[23] K. Zeger and A. Gersho. “Pseudo-Gray Coding”. IEEE Transactions on Communications, 38(12):2147–2157, December 1990. doi

[24] T. Kohonen. “Self Organization and Associative Memory”. Spring-Verlag, Berlin, 1989. 

[25] T. Kohonen. “The Self-Organizing Map”. Proceedings of the IEEE, 78(9):1464–1480, September 1994. doi

[26] W. C. Y. Lee. “Mobile Communications Engineering”. McGraw-Hill, New York, 1982. 

[27] N. Farvardin. “A Study of Vector Quantization for Noisy Channels”. IEEE Transactions on Information Theory, 36(4):799–809, July 1990. doi

[28] N. Farvardin andd J. W. Modestino. “Optimum Quantizer Performance for a Class of Non-Gaussian Memoryless Sources”. IEEE Transactions on Information Theory, IT-30(3):485–497, May 1984. 

[29] N. S. Jayant and P. Noll. “Digital Coding of Waveforms”. Prentice-Hall, Englewood Cliffs, NJ, 1984. 

[30] N. Seshadri and C. W. Sundberg. “Multilevel Trellis Coded Modulations for the Rayleigh Fading Channel”. IEEE Trans. Communications, 41(9), Sept 1993. doi

[31] B. G. Aguiar Neto. “Processamento e Transmissão Digital de Voz”. Apostila, Universidade Federal da Paraíba, 1995. 

[32] J. K. Omura. “On the Viterbi Decoding Algorithm”. IEEE Transactions on Information Theory, IT-15:6–12, September 1969. 

[33] A. Papoulis. “Probability, Random Variables, and Stochastic Processes”. McGraw-Hill, New York, 1984. 

[34] J. G. Proakis. “Digital Communications”. McGraw-Hill, New York, 1989. 

[35] R. M. Gray. “Vector Quantization”. IEEE ASSP Magazine, 1:4–29, April 1984. doi

[36] R. M. Gray and E. D. Karnin. “Multiple Local Optima in Vector Quantizers”. IEEE Transactions on Information Theory, IT-28(2):256–261, March 1982. doi

[37] S. B. Slimane. “An Improved PSK Scheme for Fading Channels”. IEEE Transactions on Vehicular Technology, 47(2):703–710, May 1998. doi

[38] S. B. Wicker. “Error Control Systems for Digital Communication and Storage”. Prentice Hall., New Jersey, 1995. 

[39] S. Carrato. “Image Vector Quantization Using Ordered Codebooks: Properties and Applications”. Signal Processing, 40:87–103, 1994. doi

[40] S. Sampei and T. Sunaga. “Rayleigh Fading Compesation for QAM in Land Mobile Radio Communications”. IEEE Transactions on Vehicular Technology, 42(2):137–147, May 1993. doi

[41] C. E. Shannon. “A Mathematical Theory of Communication”. Bell System Technical, 28:379–423 and 623–635, 1948. 

[42] T. Lookbaugh and R. M. Gray. “High-resolution Quantization Theory and Vector Quantizer Advantage”. IEEE Transactions on Information Theory, 35:1020–1033, September 1989. doi

[43] V. Tarokh, A. Naguib, N. Seshadri and A. R. Calderbank . “Space-Time Codes for High Data Rate Wireless Communication: Performance Criteria in the Presence of Channel Estimation Errors, Mobility and Multiple Paths”. IEEE Transactions on Communications, 47(2):199–207, February 1999. doi

[44] V. Tarokh, N. Seshadri and A. R. Calderbank . “Space-Time Codes for High Data Rate Wireless Communication: Performance Criterion an Code Construction”. IEEE Transactions on Information Theory, 44(2):744–765, March 1998. doi

[45] A. J. Viterbi. “Errors Bounds for Convolutional Codes and Asymptotically Optimum Decoding Algorithm”. IEEE on Communications Technology, COM-19:260–269, April 1967. 

[46] A. J. Viterbi. “Convolutional Codes and Their Performance in Communication Systems”. IEEE Transactions on Communication Technology, COM-19(5):751–772, April 1971. doi

[47] Waslon T. A. Lopes and Marcelo S. Alencar. “Improving the Space-Time Decoding Time”. In IEEE International Symposium on Wireless Communications - ISWC’99, pages 23–24, Victoria, Canada, June 1999. 

[48] A. Wittneben. “A New Bandwidth Efficient Transmit Antenna Modulation Diversity Scheme for Linear Digital Communications”. in Proc. IEEE ICC’93, pages 1630–1634, 1993. 

[49] J. M Wozencraft and I. M. Jacobs. “Principles of Communication Engineering”. John Wiley and Sons, 1965. 

[50] J. M. Wozencraft and B. Reiffen. “Sequential Decoding”. MIT Press., Cambridge, MA, 1961. 

[51] Y. Linde, A. Buzo and R. M. Gray. “An Algorithm for Vector Quantizer Design”. IEEE Transactions on Communications, COM-28:84–95, January 1980. doi

[52] Waslon T. A. Lopes, F. Madeiro, M. S. Alencar e B. G. Aguiar Neto. “Uso de Codificação na Transmissão de Imagens Quantizadas Vetorialmente em Canal Gaussiano com Desvanecimento”. XVII Simpósio Brasileiro de Telecomunicações, Vila Velha, ES, Setembro 1999.