Journal of Digital Convergence (디지털융복합연구)

The Society of Digital Policy and Management (한국디지털정책학회)
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The Performance Improvement Method using Decision Feedback Channel Estimation Scheme in PB/MC-CDMA System

PB/MC-CDMA 시스템에서 결정 귀한 채널 추정 기법을 이용한 성능 향상 방법

  • Received : 2014.10.03
  • Accepted : 2014.12.20
  • Published : 2014.12.28
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Abstract

In this paper, to improve the performance of PB/MC-CDMA system, we have researched about the decision feedback channel estimation method using the pilot symbol with data symbol. The PB/MC-CDMA system is able to obtain the improved BER by frequency diversity gain and frequency domain equalizer in the frequency selective fading channel. However, when it is not the estimating of channel exactly, it is degrading the performance of BER in the system for occurred the interference among users. To improve the performane system in the multi-user environment the proposed system is using the decision feedback to estimate channel using the channel estimated value of the first stage and second stage. The proposed system is evaluated by computer simulation. The proposed system is not only able to improve the performance of BER by decreasing the interference to each user, but also the proposed system is possible to reduce number of pilot symbol to estimate the channel. Therefore, it confirmed the proposed system improves the performance than the conventional system.

본 논문에서는, PB/MC-CDMA 시스템의 성능을 향상시키기 위한 방법으로 파일롯 심볼 및 데이터 심볼을 이용한 결정 귀환 채널 추정 기법에 대하여 연구하였다. PB/MC-CDMA 시스템은 주파수 선택적 페이딩 채널 환경에서 주파수 다이버시티 이득 및 주파수 영역 등화기를 통하여 좋은 비트오율을 얻을 수 있다. 그러나 정확한 채널 추정이 되지 않을 경우 사용자간의 심각한 간섭이 발생하기 때문에 성능 저하가 일어난다. 제안 시스템은 1차 채널 추정 값과 2차 채널 추정된 값을 결정 귀환시켜 채널을 추정함으로써 다중사용자 환경에서 시스템의 성능을 향상 시킨다. 제안시스템의 성능 평가는 컴퓨터 시뮬레이션을 통하여 수행하였다. 본 논문에서 제안시스템을 통해 사용자간의 간섭으로 인한 성능 저하를 보상하여 비트오율이 향상될 뿐만 아니라 채널 추정을 위한 파일롯 심볼의 수를 줄일 수 있어 기존의 시스템보다 더 우수한 성능을 가지는 것을 확인 하였다.

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References

  1. 3gpp: http://www.3gpp.org/Future-Radio-in3GPP-300-attend
  2. S. Hara and R. Prasad, Overview of Multicarrier CDMA. IEEE commun. Magazine. pp. 126-133, 1997.
  3. K. Adachi, F. Adachi and M. Nakagawa, Channel Capacity of MC-CDMA and Impact of Residual ICI. IEICE Trans. Commun., Vol.E92-B No.1, pp.219-227, 2009. https://doi.org/10.1587/transcom.E92.B.219
  4. J. Ahmed and K. Hamdi, Spectral Efficiency of Asynchronous MC-CDMA with Frequency Offset over Correlated Fading. IEEE Transactions on Vehicular Technology, Vol. 62, Issue 7, pp. 3423-3429, 2013. https://doi.org/10.1109/TVT.2013.2253339
  5. K. Lee and K. Lee, Adaptive Resource Allocation for the PB/MC-CDMA system in Frequency Selective Fading Channels. IEICE Trans. Commun., vol. E91-B, no. 12, pp.583-586, 2008.
  6. K. Lee and K. Lee, Joint Carrier Distribution and Frequency Hopping Scheme for Improving the BER Performance in PB/MC-CDMA Systems. IEICE Trans. Commun., vol. E92-B, no. 10, pp.3270-3273, 2009. https://doi.org/10.1587/transcom.E92.B.3270
  7. Kyujin LEE, Yan SUN and Kyesan LEE, The Joint Transmit Power Control and Frequency Band Rearrangement Shceme for PB/MC-CDMA System. IEICE Trans. Commun., vol. E94-B, no2. 2011.
  8. S. Hara and R. Prasad, Design and performance of multicarrier CDMA system in frequency-selective Rayleigh fading channels. IEEE Trans. on Vehicular Technology, vol.48, no.4, pp.1584-1595, 1999. https://doi.org/10.1109/25.790535
  9. C. Fujita, Y. Hara and Y. Kamio, Multiuser interference suppression in uplink multicarrier CDMA systems. IEICE Trans. Fundamentals, vol. E85-A, no.10, 2002.
  10. F. Adachi, T. Sao and T. Itagaki, Performance of multicode DS-CDMA using frequency domain equalization in frequency selective fading channel. Electron. Lett., vol.39, no.2, pp.239-241, 2003. https://doi.org/10.1049/el:20030160
  11. T. Uchiumi, T. Obara, Kazuki Takeda, and F. Adachi, Iterative Superimposed Pilot-Assisted Channel Estimation Using Sliding Wiener Filtering for Single-Carrier Block Transmission. IEICE Trans. Commun., Vol.E95-B, No.3, pp.924-932, 2012. https://doi.org/10.1587/transcom.E95.B.924
  12. E. Panayirci, H. Senol and H. V. Poor, Joint Channel Estimation, Equalization, and Data Detection for OFDM Systems in the Presence of Very High Mobility. IEEE Transactions on Signal Processing, Vol. 58, No. 8, pp. 4225-4238, 2010. https://doi.org/10.1109/TSP.2010.2048317
  13. Ye-Shun Shen, Fang-Biau Ueng, Wei-Liang Sung, Chiang-Chun Lee and Hsien-Chi Chang, Iterative Data Detection for Multi-Carrier Communications in Multipath Channels. 2014 IEEE International Conference on information Science, Electronics and Electrical Engineering (ISEEE), vol. 3, pp.1387-1391, 2014.
  14. T. Fujii, Y. Kamiya and Y. Suzuki, Multi-stage RLS Subcarrier Combining Method for Uplink Quasi-synchronous MC-CDMA. IEEE Trans. on Vehicular Technology, vol.56, no.6, pp.3739-3748, 2007. https://doi.org/10.1109/TVT.2007.904538
  15. G. G. Proakis and M. Salehi, Digital Communication, 5th edition, McGraw-Hill, 2008.
  16. P. Dent, G.E. Bottomly and T. Croft, Jakes fading model revisited. Electron. Lett., vol.29, no.13, pp.1162-1163, 1993. https://doi.org/10.1049/el:19930777