J4 ›› 2013, Vol. 40 ›› Issue (4): 79-84+154.doi: 10.3969/j.issn.1001-2400.2013.04.013

• Original Articles • Previous Articles     Next Articles

Beamforming assisted successive interference cancellation initial ranging algorithm for OFDMA systems

XIA Yujie1,2;REN Guangliang1   

  1. (1. State Key Lab. of Integrated Service Networks, Xidian Univ., Xi'an  710071, China;
    2. School of Physics and Electronic Information, Luoyang Normal Univ., Luoyang  471022, China)
  • Received:2012-03-20 Online:2013-08-20 Published:2013-10-10
  • Contact: XIA Yujie E-mail:yjxia@mail.xidian.edu.cn

Abstract:

According to the effect of the frequency selectivity of multipath channel and multiuser access interference (MAI) on the initial ranging system in the orthogonal frequency division multiple access (OFDMA) network, a novel beamforming assisted successive interference cancellation initial ranging algorithm is presented by utilizing smart antennas at the base station in the next generation wireless communication systems. In the algorithm, the cell is divided into many small ranging sectors in the spatial domain by a group of beamforming vectors. The proposed algorithm is able to improve the signal-to-interference-plus-noise ratio of the desired ranging users in a given sector and suppress the MAI from other ranging sectors. In the small ranging sector, the multiuser ranging code detection and timing offset estimation are conducted by the simplified successive multiuser detection and interference cancellation (SMUD) method and the adaptive threshold. Simulation results show that the correct detection probability of the proposed algorithm is improved by 80% than that of the SMUD algorithm, with 15 ranging users in the ranging channel when the SNR is -6dB.

Key words: orthogonal frequency division multiple access, beamforming, initial ranging, successive interference cancellation