Pulse or digital communications – Repeaters – Testing
Patent
1994-02-15
1995-10-31
Swann, Tod R.
Pulse or digital communications
Repeaters
Testing
380 34, H04B 169
Patent
active
054636574
ABSTRACT:
A detector of a multiple-sequence spread spectrum signal uses a Hadamard transform (106) to simultaneously correlate a received signal comprising two sequences (64) with a plurality of candidate sequences. The received signal is stripped of the first sequence (65, 66), and the signal is permuted (via a table lookup) (104). A Hadamard transform is performed on the permuted data and the candidate sequences (106). After transformation, the data is permuted again (112 ) to determine the symbol (sequence) transmitted. Alternatively, Fast Fourier Transforms (FFTs) (FIG. 3), Winograd Fourier Transform Algorithms (WFTA), or other cyclic correlation algorithms (FIG. 5) may be used to compute the transformation. In a preferred embodiment, a "pilot" signal is transmitted in quadrature (90 degrees phase offset) with an information-bearing signal. And, a block error correcting code (150) (e.g., a modified Reed-Solomon code) is transmitted with the information-bearing signal a(t). The block length of the block error correcting code (150) is equal to an integral multiple of the period of the pilot signal. The period of the pilot signal is an integral multiple of the information bearing signal. Thus, carrier recovery, sequence synchronization, and block code synchronization are all achieved simultaneously by correlating (synchronizing) the received signal with a baseband version of the pilot signal.
REFERENCES:
patent: 4672629 (1987-06-01), Beier
patent: 5022047 (1991-06-01), Dixon et al.
patent: 5063571 (1991-11-01), Vancraeynest
patent: 5210770 (1993-05-01), Rice
patent: 5218619 (1993-06-01), Dent
patent: 5267271 (1993-11-01), Rice
patent: 5341395 (1994-08-01), Bi
patent: 5341396 (1994-08-01), Higgins et al.
M. Leonard, "Networked Controllers Talk Over Power Lines, " Electronic Design, Sep. 17, 1992, vol. 40, No. 19.
P. Enge and D. Sarwate, "Spread-Spectrum Multiple-Access Performance of Orthogonal Codes: Linear Receivers," IEEE Transactions on Communications, vol. COM-35, No. 12, pp. 1309-1319, Dec. 1987.
K. Pahlavan and M. Chase, "Spread-Spectrum Multiple-Access Performance of Orthogonal Codes for Indoor Radio Communications, " IEEE Transactions on Communications, vol. 38, No. 5, pp. 574-577, May 1990.
W. E. Stark and B. D. Woerner, "The Application of Trellis Coding Techniques to Direct-Sequence Spread-Spectrum Multiple Access Communications," Proc. 26th Allerton Conf. on Communications, Control, and Computing, pp. 1070-1079, 1988.
B. F. Rice, "A Transceiver Design for a High Information Rate LPI Network, "Proc. Milcom '90, pp. 49.1.1-49.1.4.
R. Kerr, "The CDMA Digital Cellular System: An ASIC Overview, " Proc. of the Third IEEE International Symposium on Personal, Indoor and Mobile Radio Communications,. pp. 2.2.1-2.2.6, Oct. 1992.
F. J. MacWilliams and N. J. A. Sloan, The Theory of Error Correcting Codes, North Holland Publishing Company, 1978.
N. Kuroyanagi and L. Guo, "Proposal of an Alternate M-Sequence Spread Spectrum System, "Proceedings Milcom '93, Oct. 1993.
R. Gold, "Optimal Binary Sequences for Spread Spectrum Multiplexing," IEEE Trans. On Information Theory, vol. IT-13, pp. 119-121, Oct. 1967.
M. Simon, J. Omura, R. Scholtz, and B. K. Levitt, Spread Spectrum Communications, vol. 1, Computer Science Press, 1985, pp. 326-339.
D. Sarwate and M. Pursley, "Crosscorrelation Properties of Pseudorandom and Related Sequences," Proc. of the IEEE, vol. 68, No. 5, pp. 593-619, May 1980.
D. King, T. Mullen, B. Rice, P. Topping, N. Weyland, "Knowledge-Based FFT and Convolution Synthesis for Any Number of Points," Mathematics and Computers in Simulation 31 (1989), pp. 441-451.
J. C. Gower, "The Yates Algorithm," Utilitas Mathematica, vol. 21B, pp. 99-115, 1982.
Leon W. Couch II, Digital and Analog Comunication Systems, MacMillan Press 1990, pp. 130-133.
Joseph W. White, "What is CDMA?", Applied Microwave & Wireless, Fall 1993, pp. 5-8.
Bart F. Rice, "Sequence Generation and Detection for Variable Rate CDMA Networks" Proceedings of the Second Annual Wireless Symposium, Feb. 15-18, 1994.
Cary Judson D.
Lockheed Missiles & Space Company Inc.
Radlo Edward J.
Swann Tod R.
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