Abstract
It is known that the capacity of parallel (multicarrier) Gaussian point-to-point, multiple access and broadcast channels can be achieved by separate encoding for each subchannel (carrier) subject to a power allocation across carriers. In this paper we show that such a separation does not apply to parallel Gaussian interference channels in general. A counterexample is provided in the form of a 3 user interference channel where separate encoding can only achieve a sum capacity of 2 log(1 + 3 SNR) while the actual capacity, achieved only by joint encoding across carriers, is 3 log(1 + 2 SNR). As a byproduct of our analysis, we propose a class of multiple-access-outer bounds on the capacity of the 3 user interference channel.
Original language | English (US) |
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Pages (from-to) | 3983-3990 |
Number of pages | 8 |
Journal | IEEE Transactions on Information Theory |
Volume | 55 |
Issue number | 9 |
DOIs | |
State | Published - 2009 |
All Science Journal Classification (ASJC) codes
- Information Systems
- Computer Science Applications
- Library and Information Sciences