Pulse or digital communications – Equalizers
Reexamination Certificate
2005-07-05
2005-07-05
Burd, Kevin (Department: 2631)
Pulse or digital communications
Equalizers
Reexamination Certificate
active
06914934
ABSTRACT:
Signal processing operations are performed in a digital communication system receiver on a sequence of received symbols, each representing a number of information bits. The symbols correspond to points in a given modulation constellation generated by applying a predetermined rotation, e.g., a 45° rotation, to an otherwise conventional modulation constellation, e.g., a QPSK constellation, a 16-QAM constellation, etc. The use of the rotated constellation allows certain signal processing operations, such as filtering, Least-Mean-Squares (LMS) estimation, and Maximum-Likelihood (ML) sequence detection via the Viterbi algorithm, to be performed without the need for multipliers. By eliminating or substantially reducing the number of required multiplication operations, the invention significantly reduces the complexity and delay associated with the corresponding signal processing circuitry. Advantageously, this reduction in complexity and delay is accomplished without the use of any approximation or other reduction in precision.
REFERENCES:
patent: 4381546 (1983-04-01), Armstrong
patent: 4520490 (1985-05-01), Wei
patent: 5289501 (1994-02-01), Seshadri et al.
patent: 6233271 (2001-05-01), Jones et al.
patent: 6611567 (2003-08-01), Balakrishnan et al.
Randy H. Katz, Contemporary Logic Design, The Benjamin/Cummings Publishing Company, Inc, pp. 266-269.
Durant et al, “Implementation of a Broadband Equalizer for High-Speed Wireless Data Communications”, IEEE, 1015-1020.
S. Ariyavisitakul et al, “Reduced-complexity equalization techniques for broadband wireless channels,” IEEE Journals of Selected Areas in Communications, vol. 15, pp 5-15, Jan. 1997.
G.M. Durant et al., “Implementation of a Broadband Equalizer for High-Speed Wireless Data Applications,” Proc. IEEE ICUPC 98, Florence, Italy, pp. 1015-1020, Oct. 1998.
T.A.C.M. Claasen et al., “Comparison of the Convergence of Two Algorithms for Adaptive FIR Digital Filters,” IEEE Trans. on Acoustics, Speech and Signal Processing, vol. ASSP-29, No. 3, pp. 670-678, Jun. 1981.
D.L. Duttweiler, “A Twelve-Channel Digital Echo Canceler,” IEEE Trans. on Communications, vol. COM-26, No. 5, pp. 647-653, May 1978.
R.D. Gitlin et al., “On the Design of Gradient Algorithms for Digitally Implemented Adaptive Filters,” IEEE Trans. on Circuit Theory, vol. CT-20, No. 2, pp. 125-136, Mar. 1973.
M.D. Meyer et al., “A Modular Pipelined Implementation of a Delayed LMS Transversal Adaptive Filter,” Proc. of ISCAS, New Orleans, pp. 1943-1946, 1990.
P. Kabal, “The Stability of Adaptive Minimum Mean Square Error Equalizers Using Delayed Adjustment,” IEEE Trans. on Communications, vol. COM-31, No. 3, pp. 430-432, Mar. 1983.
G. Long et al., “The LMS Algorithm with Delayed Coefficient Adaptation,” IEEE Trans. on Acoustics, Speech and Signal Processing, vol. 37, No. 9, pp. 1397-1405, Sep. 1989.
G. Long et al., “Corrections to ‘The LMS Algorithm with Delayed Coefficient Adaptation’,” IEEE Trans. on Signal Processing, vol. 40, No. 1, pp. 230-232, Jan. 1992.
M. Rupp et al., “Analysis of LMS and NLMS Algorithms with Delayed Coefficient Updated Under the Presence of Spherically Invariant Processes,” IEEE Trans. on Signal Processing, vol. 42, No. 3, pp. 668-672, Mar. 1994.
E. Bjarnason, “Active Noise Cancellation Using a Modified Form of the Filtered-X LMS Algorithm,” Proc. Eusipco Signal Processing VI, Brüssel, pp. 1053-1056, 1992.
T. Kimijima et al., “A Pipelined Architecture for DLMS Algorithm Considering Both Hardware Complexity and Output Latency,” Proc. Eusipco, Patras, Greece, pp. 503-506, Sep. 1998.
Lou Hui-Ling
Rupp Markus
Agere Systems Inc.
Burd Kevin
LandOfFree
Multiplier-free methods and apparatus for signal processing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multiplier-free methods and apparatus for signal processing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multiplier-free methods and apparatus for signal processing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3379860