Distributed Transmission in Relay Coordinated Multi-point (COMP) Networks

Pilaram, Hossein | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 43411 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Hossein Khalaj, Babak; Behroozi, Hamid
  7. Abstract:
  8. Time offset (TO) at an orthogonal frequency division multiplexing (OFDM) system destroys orthogonality of subcarriers and causes interchannel interference (ICI) and inter symbol interference (ISI). This problem is more challenging in multi-user multi-input multi-output (MU-MIMO) OFDM systems such as coordinated multi-point (CoMP) uplink transmission where joint processing is performed at base stations (BSs) and different delays form users to BSs cannot be compensated by timing strategies. In this thesis, we use delay-amplify and forward relays and post processing at receivers to decrease signal to interference plus noise ratio (SINR) degradation due to large TOs at insufficient cyclic prefix (CP) length case in CoMP uplink direction. In addition, we optimize adjustable manual delays at both users and BSs sides. The design goal is determine manual delays at users, relays, and BSs at first level that an iteration algorithm is proposed. Then, we optimize relay’s weights and post processing matrices at receiver at constraint of total relay transmitted power using an iterative method by fixing one of them at each iteration that converts the problem to two simple subproblem consisting of designing a minimum mean square error (MMSE) receiver and a feasibility convex second order cone programming (SOCP) problem. Numerical results show these methods improve SINR of the system.

  9. Keywords:
  10. Relay Channel ; Beamforming ; Orthogonal Frequency Division Multiplexing (OFDM) ; Synchronisation ; Multi-Cell Networks ; Coordinated Multipoint (CoMP)Networks

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