International Journal of Computer Science & Network Security

국제컴퓨터통신보호논문지학회 (International Journal of Computer Science & Network Security)
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A 2×2 MIMO Spatial Multiplexing 5G Signal Reception in a 500 km/h High-Speed Vehicle using an Augmented Channel Matrix Generated by a Delay and Doppler Profiler

  • 투고 : 2023.10.05
  • 발행 : 2023.10.30
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초록

This paper proposes a method to extend Inter-Carrier Interference (ICI) canceling Orthogonal Frequency Division Multiplexing (OFDM) receivers for 5G mobile systems to spatial multiplexing 2×2 MIMO (Multiple Input Multiple Output) systems to support high-speed ground transportation services by linear motor cars traveling at 500 km/h. In Japan, linear-motor high-speed ground transportation service is scheduled to begin in 2027. To expand the coverage area of base stations, 5G mobile systems in high-speed moving trains will have multiple base station antennas transmitting the same downlink (DL) signal, forming an expanded cell size along the train rails. 5G terminals in a fast-moving train can cause the forward and backward antenna signals to be Doppler-shifted in opposite directions, so the receiver in the train may have trouble estimating the exact channel transfer function (CTF) for demodulation. A receiver in such high-speed train sees the transmission channel which is composed of multiple Doppler-shifted propagation paths. Then, a loss of sub-carrier orthogonality due to Doppler-spread channels causes ICI. The ICI Canceller is realized by the following three steps. First, using the Demodulation Reference Symbol (DMRS) pilot signals, it analyzes three parameters such as attenuation, relative delay, and Doppler-shift of each multi-path component. Secondly, based on the sets of three parameters, Channel Transfer Function (CTF) of sender sub-carrier number n to receiver sub-carrier number l is generated. In case of n≠l, the CTF corresponds to ICI factor. Thirdly, since ICI factor is obtained, by applying ICI reverse operation by Multi-Tap Equalizer, ICI canceling can be realized. ICI canceling performance has been simulated assuming severe channel condition such as 500 km/h, 8 path reverse Doppler Shift for QPSK, 16QAM, 64QAM and 256QAM modulations. In particular, 2×2MIMO QPSK and 16QAM modulation schemes, BER (Bit Error Rate) improvement was observed when the number of taps in the multi-tap equalizer was set to 31 or more taps, at a moving speed of 500 km/h and in an 8-pass reverse doppler shift environment.

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참고문헌

  1. Suguru Kuniyoshi, Rie Saotome, Shiho Oshiro and Tomohisa Wada, "An ICI Canceling 5G system receiver for 500km/h linear motor car," IJCSNS International Journal of Computer Science and Network Security, VOL.23, No.6, pp.27-34, June 2023.
  2. 3GPP TS38.211 V17.4.0: "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Physical channels and modulation" Dec. 2022.
  3. Erik Dahlman, Stefan Parkvall, Johan Skold (2021). 5G NR THE NEXT GENERATION WIRELESS ACCESS TECHNOLOGY SECOND EDITION. Academic Press.
  4. Mitsuru Nakamura, Makoto Itami, Kohji Itoh and Hamid Aghvami, "ICI Cancellation Technique based on Estimating Delay and Doppler Profile in OFDM Reception," The Institute of Image Information and Television Engineers, Vol. 56, No. 12, pp.1951-1958 (2002). https://doi.org/10.3169/itej.56.1951
  5. Mitsuru Nakamura, Masahiro Fujii, Makoto Itami and Kohji Itoh, "MMSE ICI Canceller for OFDM Mobile Reception," The Institute of Image Information and Television Engineers, Vol. 58, No. 1, pp.83-90 (2004). https://doi.org/10.3169/itej.58.83
  6. Akito Yamazaki, Mitsuru Nakamura, Masahiro Fujii, Makoto Itami, Kohji Itoh and Hiroki Ohta, "A Study on Improving Performance of an OFDM ICI Canceller," The Institute of Image Information and Television Engineers, Vol. 58, No. 1, pp.94-101 (2005). https://doi.org/10.3169/itej.59.94
  7. Suguru Kuniyoshi, Rie Saotome, Shiho Oshiro and Tomohisa Wada, "Delay and Doppler Profiler based Channel Transfer Function estimation for 2×2 MIMO Receivers in 5G system targeting a 500km/h linear motor car," IJCSNS International Journal of Computer Science and Network Security, VOL.23, No.9, pp.8-16, September 2023.