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Channel Estimation in mmWave MIMO Systems

Bemani Zare Sharifabad, Ali | 2017

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50212 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Nasiri Kenari, Masoumeh
  7. Abstract:
  8. Millimeter-wave (mmWave) communication systems exhibit large bandwidth and severe channel attenuations. To maintain the received signal-to-noise ratio on an acceptable level, mmWave systems use large antenna arrays and directional beamforming at both transmitter and receiver. The existence of many antenna elements, however, challenges traditional approaches for pilot transmission and channel estimation wherein the number of pilots linearly scales up with the total number of transmit antennas. For instance, for the uplink channel estimation with a constant coherence interval, adding more antennas to the users comes at the expense of a linear penalty on the number of users, which can prohibit the application of mmWave networks to massive wireless access. In this thesis, we investigate the efficient pilot transmission and channel estimation procedures for mmWave networks. Given an error-free knowledge of the channel covariance matrix, we propose to use precoder for the pilot signals and find the optimal precoder. We show that the optimal precoding and combining vectors depend only on the second-order statistics of the channel, the maximum number of orthogonal pilots is the number of paths, which could be orders of magnitude smaller than the number of antennas, and the optimal power allocation follows a water-filling structure. Moreover, the proposed approach improves the channel estimation performance, which leads to a better design of the data beamforming phase. We investigate the performance of our approach when being designed based on a noisy channel covariance matrix. With extensive mathematical and numerical performance evaluations, we study the effect of important design parameters including the number of transmit/receive antennas, the number of paths, the number of users, in the performance of our proposed approach
  9. Keywords:
  10. Millimeter Wave ; Channel Estimation ; Multiple Input Multiple Output (MIMO)System

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