TY - GEN

T1 - Two new types of candidate symbol sorting schemes for complexity reduction of a sphere decoder

AU - Eun, Sung Jeon

AU - Yo, Han Kim

AU - Dong, Ku Kim

N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.

PY - 2007

Y1 - 2007

N2 - The computational complexity of a sphere decoder (SD) is conventionally reduced by decoding the order scheme which sorts candidate symbols in the ascending order of the Euclidean distance from the soft-output signal points of a zero-forcing (ZF) receiver. However, since the soft-output signal point of ZF may not be a reliable sorting reference, we propose two types of sorting schemes to allow faster decoding. The first is to use the newly found lattice points in the previous search round instead of the ZF solution (Type I). Since these lattice points are closer to the received signal than the ZF solution, they can serve as a more reliable sorting reference for finding the maximum likelihood (ML) solution. The second sorting scheme is to sort candidate symbols in descending order according to the number of candidate symbols in the following layer, which are called child symbols (Type II). These two proposed sorting schemes can be combined with layer sorting for more complexity reduction. Through simulation, the Type I and Type II sorting schemes were found to provide 12% and 20% complexity reduction respectively over conventional sorting schemes. When they are combined with layer sorting, Type I and Type II provide an additional 10-15% complexity reduction while maintaining detection performance.

AB - The computational complexity of a sphere decoder (SD) is conventionally reduced by decoding the order scheme which sorts candidate symbols in the ascending order of the Euclidean distance from the soft-output signal points of a zero-forcing (ZF) receiver. However, since the soft-output signal point of ZF may not be a reliable sorting reference, we propose two types of sorting schemes to allow faster decoding. The first is to use the newly found lattice points in the previous search round instead of the ZF solution (Type I). Since these lattice points are closer to the received signal than the ZF solution, they can serve as a more reliable sorting reference for finding the maximum likelihood (ML) solution. The second sorting scheme is to sort candidate symbols in descending order according to the number of candidate symbols in the following layer, which are called child symbols (Type II). These two proposed sorting schemes can be combined with layer sorting for more complexity reduction. Through simulation, the Type I and Type II sorting schemes were found to provide 12% and 20% complexity reduction respectively over conventional sorting schemes. When they are combined with layer sorting, Type I and Type II provide an additional 10-15% complexity reduction while maintaining detection performance.

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M3 - Conference contribution

AN - SCOPUS:52249087816

SN - 0769530486

SN - 9780769530482

T3 - Proceedings of Future Generation Communication and Networking, FGCN 2007

SP - 80

EP - 84

BT - Proceedings - CIS Workshops 2007, 2007 International Conference on Computational Intelligence and Security Workshops, CISW 2007

T2 - 2007 International Conference on Future Generation Communication and Networking, FGCN 2007

Y2 - 6 December 2007 through 8 December 2007

ER -