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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Codebook design for distributed relay beamforming system

Zheng, Min 01 April 2012 (has links)
In FDD amplify-and-forward distributed relay network, codebook techniques are utilized to feedback quantized CSI with limited cost. First, this thesis focuses on the phaseonly codebook and with-power-control codebook design methods under individual relay power constraints. Phase-only codebooks can be generated off-line with the Grassmannian beamforming criterion. Due to non-uniform distribution of the optimal beamforming vector in the vector space, The Lloyd’s algorithm is proposed for with-power-control codebook designs. To reduce search complexity, a suboptimal method for the codebook update stage in the Lloyd’s algorithm is proposed. Its performance is compared to the performance of the global search method which provides the optimal solution but incurs high computation complexity. Second, this thesis investigates the performance difference between phaseonly and with-power-control codebooks. It is found that the power control gain is tightly related to the relay locations. When the relays are close to the source node, the gain from power control is negligible and using phase-only codebooks becomes a viable choice for feedback due to its simple implantation and off-line computation. Finally, the problem of codebook design extends to the total relay power constraint case, and the Lloyd’s algorithm with primary eigenvector method is proposed to design a suboptimal codebook. / UOIT

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