Beamforming with Limited Feedback in Amplify-and-Forward Cooperative Networks

— A relay selection approach has previously been shown to outperform repetition-based scheduling for both amplify-and-forward (AF) and decode-and-forward (DF) cooperative networks. The selection method generally requires some feedback from the destination to the relays and the source, raising the issue of the interplay between performance and feedback rate. In this letter, we treat selection as an instance of limitedfeedback distributed beamforming in cooperative AF networks, and highlight the differences between transmit beamforming in a traditional multi-input single-output (MISO) system and the distributed case. Specifically, Grassmannian line packing (GLP) is no longer the optimal codebook design, and orthogonal codebooks are no longer equivalent to each other. We derive the high signal-to-noise ratio expressions for outage probability and probability of symbol error for unlimited-feedback and selection schemes, which are then used for performance comparisons. The selection prot...

• Type: Conference
• Year: 2007
• Where: GLOBECOM
• Authors: Yi Zhao, Raviraj Adve, Teng Joon Lim
• Keywords: GLOBECOM 2007, Relay Selection Approach, Selection, Selection Protocol, Telecommunications