Cellular interference alignment.

摘要: Interference alignment promises that, in Gaussian interference channels, each link can support half of a degree freedom (DoF) per pair transmit-receive antennas. However, general, this result requires to precode the data bearing signals over signal space asymptotically large diversity, e.g., an infinite number dimensions for time-frequency varying fading or rationally independent levels, case invariant channels. In paper, we consider wireless cellular system scenario where promised optimal DoFs are achieved with linear precoding one-shot (i.e., single slot). We focus on uplink symmetric system, cell is split into three sectors orthogonal intrasector multiple access. our model, local, i.e., it due transmitters neighboring cells only. noniterative local cooperation scheme base stations pass their neighbors decoded messages such that from already be canceled. Therefore, given decoding order, between described by directed locally connected graph. The problem consists maximizing per-sector all possible orders and schemes. particular, provide order able achieve DoFs, up additive gap boundary effects, vanishes as size network becomes large. Then, extend treatment considering intersector joint processing sector at site. avoid signaling schemes relying strength interference, further introduce notion topologically robust schemes, which guarantee minimum rate (or DoFs) irrespectively interfering links. Toward end, design different scheme, still achieves same optimum DoFs. Finally, new downlink, based station cooperation, quantized version dirty-paper coded signals. For proposed downlink prove duality showing appropriate choice beamforming vectors, corresponding