Scheduled System Maintenance:
Some services will be unavailable Sunday, March 29th through Monday, March 30th. We apologize for the inconvenience.
By Topic

On Improving the Efficiency of the Fixed-Complexity Sphere Decoder

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

The purchase and pricing options are temporarily unavailable. Please try again later.
2 Author(s)
Mohaisen, M. ; Grad. Sch. of IT & T, Inha Univ., Incheon, South Korea ; KyungHi Chang

Fixed-complexity sphere decoder (FSD), which consists of ordering stage and tree-search stage, achieves a quasiML performance while requiring a fixed computational effort independent of the noise power and channel conditioning. Nevertheless, it requires a specific signal ordering using the VBLAST algorithm which has a high complexity due to the iterative pseudo-inversion of the channel matrix. In this paper, we propose two schemes to reduce the complexity of FSD algorithm in the ordering and tree-search stages, respectively, while achieving quasi-ML performance. In the ordering stage, we propose QR-decomposition-based FSD signal ordering (FSDSQRD) that requires only a few number of additional complex flops compared to the unsorted QRD. In the tree-search stage, we introduce a threshold-based complexity reduction approach for FSD depending on the reliability of the signal with the lowest received SNR. Numerical results show that in a 4×4 system, the proposed FSD-SQRD requires only 17.2% of the computational efforts required by a reduced-complexity VBLAST approach. Moreover, using 16-QAM, simulation results show that when the proposed threshold-based approach is employed, FSD requires only 69.5% of its full complexity.

Published in:

Vehicular Technology Conference Fall (VTC 2009-Fall), 2009 IEEE 70th

Date of Conference:

20-23 Sept. 2009