Interference alignment on multigroup multi way relay channels

Okutan, Mehmet Akif
Interference is a major problem for reliable multiuser communications. There are several ways to manage interference which are applied according to the power of interference compared to the power of desired signal. If interference is powerful than the desired signal then interference signal is decoded. Otherwise if it is much weaker than the desired signal it may be considered as noise. If signal powers of the desired signal and the interference are comparable then orthogonalizing all the signals from all the users can be a solution. By orthogonalizing user signals, capacity is shared in between users. Interference alignment is a relatively new technique used for interference cancellation in multiuser networks. It is based on aligning unwanted signals and desired signals into distinct and orthogonal subspaces. Theoretically, in a K user interference channel, every user can use half of the sum capacity by applying interference alignment. In this work, we consider interference alignment on multi group multi way relaying channels. Each node in each group is interested in the data streams transmitted by other nodes in the same group. Data streams of the other groups are considered as interference. We develop an interference alignment solution for this scenario, by aligning M nodes in each group into the same subspace at the relay. Therefore the number of antennas needed at the relay are reduced by an order of M. The price paid for this is the increase in the number of time slots needed for the communication between nodes.


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Citation Formats
M. A. Okutan, “Interference alignment on multigroup multi way relay channels,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Electrical and Electronics Engineering., Middle East Technical University, 2019.