DocumentCode :
2325872
Title :
CTH06-6: Optimized Transmission for Upstream Vectored DSL Systems Using Zero-Forcing Generalized Decision-Feedback Equalizers
Author :
Chen, Chiang-Yu ; Seong, Kibeom ; Zhang, Rui ; Cioffi, John M.
Author_Institution :
Dept. of Electr. Eng., Stanford Univ., Stanford, CA
fYear :
2006
fDate :
Nov. 27 2006-Dec. 1 2006
Firstpage :
1
Lastpage :
5
Abstract :
In upstream vectored DSL transmission, the far-end crosstalk (FEXT) can be completely cancelled by using zero- forcing generalized decision-feedback equalizers (ZF-GDFE). When the spatially correlated alien crosstalk is present, the achievable data rates of DSL lines with ZF-GDFE depend on their decoding orders at each DMT tone. Given a weighted sum-rate maximization problem, the optimal orderings for all DMT tones can be found by the Lagrange dual decomposition method. However, the computational complexity of such approach grows with the factorial of the number of users, which makes the optimal search infeasible with a large number of vectored lines. This paper presents a modified greedy algorithm (MGA) that performs close to the optimal search of decoding orders. The complexity of MGA is only proportional to the cube of the number of users, which is the same as it of QR decomposition. With a significant reduction of complexity, MGA is a promising technique for practical DSL systems.
Keywords :
computational complexity; crosstalk; decision feedback equalisers; decoding; digital subscriber lines; greedy algorithms; optimisation; search problems; DMT tone; FEXT; Lagrange dual decomposition method; QR decomposition; ZF-GDFE; computational complexity; digital subscriber line systems; discrete multitone symbol; far-end crosstalk; modified greedy algorithm; optimal decoding order search; optimized upstream vectored DSL transmission system; spatial correlated alien crosstalk; weighted sum-rate maximization problem; zero-forcing generalized decision-feedback equalizer; Computational complexity; Crosstalk; DSL; Decision feedback equalizers; Decoding; Lagrangian functions; Noise cancellation; OFDM modulation; Optical network units; Optical receivers;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Global Telecommunications Conference, 2006. GLOBECOM '06. IEEE
Conference_Location :
San Francisco, CA
ISSN :
1930-529X
Print_ISBN :
1-4244-0356-1
Electronic_ISBN :
1930-529X
Type :
conf
DOI :
10.1109/GLOCOM.2006.69
Filename :
4150699
Link To Document :
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