The Dirty MIMO Multiple-Access Channel

• Published in: IEEE transactions on information theory 2017-09, Vol.63 (9), p.6031-6040
• Main Authors: Khina, Anatoly, Kochman, Yuval, Erez, Uri
• Format: Article
• Language: English
• Subjects: Communication channels; Decomposition; dirty-paper coding; Encoding; Interference; Matrix decomposition; MIMO; Multiple-access channel; multiple-input multiple-output channel; physical-layer network coding; Random noise; Receivers; Scaling factors; Signal to noise ratio; Transmitters; two-way relay channel
• ISSN: 0018-9448; 1557-9654
• DOI: 10.1109/TIT.2017.2698443

In the scalar dirty multiple-access channel, in addition to Gaussian noise, two additive interference signals are present, each known non-causally to a single transmitter. It was shown by Philosof et al. that for strong interferences, an independent identically distributed ensemble of codes does not achieve the capacity region. Rather, a structured-codes approach was presented that was shown to be optimal in the limit of high signal-to-noise ratios, where the sum capacity is dictated by the minimal ("bottleneck") channel gain. In this paper, we consider the multiple-input multiple-output (MIMO) variant of this setting. In order to incorporate structured codes in this case, one can utilize matrix decompositions that transform the channel into effective parallel scalar dirty multiple-access channels. This approach, however, suffers from a "bottleneck" effect for each effective scalar channel and, therefore, the achievable rates strongly depend on the chosen decomposition. It is shown that a recently proposed decomposition, where the diagonals of the effective channel matrices are equal up to a scaling factor, is optimal at high signal-to-noise ratios, under an equal rank assumption. This approach is then extended to any number of transmitters. Finally, an application to physical-layer network coding for the MIMO two-way relay channel is presented.