Chapter 19: Turbo Principle and Iterative Receivers

Learning Objectives

• Explain the turbo principle: iterative exchange of extrinsic information between coupled soft-input soft-output blocks
• Construct and interpret EXIT charts to predict decoding convergence and the turbo cliff
• Derive the MMSE-PIC turbo equalizer and analyse its fixed points
• Design and analyse iterative MIMO detection with soft feedback from a channel decoder
• Formulate expectation propagation as projection of intractable messages onto a Gaussian family via moment matching
• Relate EP to loopy belief propagation and to LMMSE-based iterative receivers