Channel estimation in OFDMA communication systems requires transmission of pilot symbols. For a frequency selective fading channel, multiple pilots are needed in a single OFDM frame for the receivers/users to perform channel estimation. Comb-type pilots are a commonly used pilot allocation technique. However, such estimation techniques may have high computational complexity. In this work, we propose a matched pilot resource allocation approach which concentrates allocation of pilot subcarriers to particular users, to reduce the computational complexity at each of the receivers. In particular, we show that the proposed pilot assignment technique’s reduction in complexity improves as the number of channel taps increases. We also show that the proposed technique’s complexity reduction scales well in NOMA-OFDMA systems, where multiple users’ information may be multiplexed on a single subcarrier.

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A Matched Pilot Resource Allocation Scheme for Downlink OFDMA Systems

  • Krishnan B. Iyengar,
  • Raghavendra Pal,
  • Upena D. Dalal,
  • Anupam Shukla

摘要

Channel estimation in OFDMA communication systems requires transmission of pilot symbols. For a frequency selective fading channel, multiple pilots are needed in a single OFDM frame for the receivers/users to perform channel estimation. Comb-type pilots are a commonly used pilot allocation technique. However, such estimation techniques may have high computational complexity. In this work, we propose a matched pilot resource allocation approach which concentrates allocation of pilot subcarriers to particular users, to reduce the computational complexity at each of the receivers. In particular, we show that the proposed pilot assignment technique’s reduction in complexity improves as the number of channel taps increases. We also show that the proposed technique’s complexity reduction scales well in NOMA-OFDMA systems, where multiple users’ information may be multiplexed on a single subcarrier.