DOI QR코드

DOI QR Code

공간 채널 모델의 통계적 특성을 반영한 다중 랭크 코드북의 설계 및 성능 이득 평가

Design and Performance Gain Evaluation of a Multi-Rank Codebook Utilizing Statistical Properties of the Spatial Channel Model

  • Kim, Changhyeon (Sogang University Department of Electronic Engineering) ;
  • Sung, Wonjin (Sogang University Department of Electronic Engineering)
  • 투고 : 2016.05.10
  • 심사 : 2016.06.23
  • 발행 : 2016.07.31

초록

5G 이동무선통신에서 요구되는 증가된 데이터 속도를 제공하기 위한 핵심적인 기술 축은 대규모 어레이를 활용하는 MIMO 전송을 통한 주파수 효율의 향상이다. MIMO 전송을 위해서는 CSI-RS (channel state information-reference signaling)를 이용하는 채널 추정 및 추정 결과에 적합한 빔포밍이 필요하며, 따라서 빔포밍 벡터를 정의하는 코드북의 설계는 매우 중요한 이슈이다. 본 논문에서는 공간채널모델을 이용하여 생성된 채널의 통계적인 특성을 활용하여 DFT (discrete Fourier transform) 행렬 기반 다중 랭크 코드북의 설계 방안을 제안하였다. 제안 방식은 인접한 안테나 원소 간 위상차의 분포와 전송 레이어 별 선택되는 코드벡터의 특징을 고려하여 PMI (precoding matrix indicator)의 구조 변경을 하였으며, LTE (long-term evolution) 시스템에서 사용 중인 3GPP 표준 코드북과의 성능 비교를 통하여 제안 방식의 이득을 산출하고 검증하였다.

A core technological base to provide enhanced data rates required by 5G mobile wireless communications is the improved bandwidth efficiency using massive multiple-input multiple-output (MIMO) transmission. MIMO transmission requires the channel estimation using the channel state information reference signaling (CSI-RS) and appropriate beamforming, thus the design of the codebook defining proper beamforming vectors is an important issue. In this paper, we propose a multi-rank codebook based on the discrete Fourier transform (DFT) matrix, by utilizing statistical properties of the channel generated by the spatial channel model (SCM). The proposed method includes a structural change of the precoding matrix indicator (PMI) by considering the phase difference distributions between adjacent antenna elements, as well as the selected codevector characteristics of each transmission layer. Performance gain of the proposed method is evaluated and verified by making the performance comparison to the 3GPP standard codebooks adopted by Long-Term Evolution (LTE) systems.

키워드

참고문헌

  1. J. Ahn and P. Song, "Further development perspectives of 5G mobile communications (3GPP 기반 5G 이동통신 기술 발전 전망)," KICS, vol. 30, no. 5, pp. 37-50, Dec. 2013.
  2. D. Kim, A. Park, and C. Kang, "Vision and Strategy for 5G mobile communications (5G 이동통신 비젼 및 추진전략)," KICS, vol. 30, no. 5, pp. 3-11, Dec. 2013.
  3. C. Lim, T. Yoo, B. Clerckx, B. Lee, and B. Shim, "Recent trend of multiuser MIMO in LTE-advanced," IEEE Commun. Mag., vol. 51, no. 3, pp. 127-135, Mar. 2013. https://doi.org/10.1109/MCOM.2013.6476877
  4. T. Shuang, et al., "Design and evaluation of LTE-Advanced double codebook," in Proc. VTC-spring 2011, pp. 1-5, Yokohama, JPN, May 2011.
  5. Y. Han, X. Li, Y. Huang, L. Jiang, and G. Wang, "Design of double codebook based on 3D dual-polarized channel for multiuser MIMO system," EURASIP J. Advances in Signal Processing, vol. 2014, no. 1, Dec. 2014.
  6. X, Yun, et al., "Investigation of optimum double codebook design for downlink MIMO in LTE-A," in Proc. VTC-spring 2011, pp. 1-5, Budapest, Hungary, May 2011.
  7. Y. Dai, et al., "A PMI feedback scheme for downlink multi-user MIMO based on dualcodebook of LTE-advanced," in Proc. VTC-Fall 2012, pp. 1-5, Quebec City, Canada, Sept. 2012.
  8. T. Hiltunen, M. Lampinen, and M. Valkama, "Codebook design and link level performance of closed-loop 4x2 MIMO in HSDPA," in 2013 IEEE Int. Wirel. Symp. (IWS), Bejing, China, Apr. 2013.
  9. 3GPP, Evolved universal terrestrial radio access, (E-UTRA); Physical channels and modulation, 3GPP TS 26.211 v10.7.0(2013), Retrieved April 27, 2016, from http://www.3gpp.org/ftp/Specs/archive/36_series/36.211/36211-a70.zip
  10. R1-156217, WF on class A and class B CSI reporting for EB/FD-MIMO
  11. 3GPP, Technical specification group radio access network; Study on 3D channel model for LTE, 3GPP TR. 36.873 v12.2.0(2015), Retrieved April 27, 2016, from http://www.3gpp.org/ftp/Specs/archive/36_series/36.873/36 873-c20.zip
  12. Y. Xie, et al., "A limited feedback scheme for 3D multiuser MIMO based on Kronecker product codebook," in 2013 IEEE 24th Int. Symp. PIMRC, pp. 1130-1135, London, UK, Sept. 2013.
  13. J. Ahn, D. Lee, C. Park, H. Kim, and J. Chung, "Code-book based beamforming techniques for improving SIR," J. KICS, vol. 15, no. 8, pp. 1469-1476, Aug. 2015.