A Note on Capacity Computation for the Discrete Multiple Access Channel
A Note on Capacity Computation for the Discrete Multiple Access Channel
复制标题
离散多址信道容量计算的一个注解
DOI：
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复制
发表时间：
2011
影响因子：
2.5
通讯作者：
G. Wunder
中科院分区：
文献类型：
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作者：
Jörg Bühler;G. Wunder
本文研究了离散无记忆多址信道(MAC)的容量域的计算，它等价于求解一个困难的非凸优化问题。在文献中，声称对于基本MAC，即其输出字母表的大小大于或等于所有输入字母表的大小的MAC，Karush-Kuhn-Tucker条件提供了和速率最优的充要条件。在这篇文章中，我们证明了这一主张不成立，即使对于具有二进制输入和二进制输出字母表的两用户通道也是如此。因此，离散MAC层的容量计算问题仍然是一个有趣且大部分未解决的问题。
This paper deals with computation of the capacity region of the discrete memoryless multiple-access channel (MAC), which is equivalent to solving a difficult nonconvex optimization problem. In the literature, it is claimed that for elementary MACs, i.e., MACs for which the size of output alphabet is greater or equal to the sizes of all input alphabets, the Karush-Kuhn-Tucker conditions provide a necessary and sufficient condition for sum-rate optimality. In this paper, we demonstrate that this claim does not hold, even for two-user channels with binary input and binary output alphabets. Consequently, the capacity computation problem for the discrete MAC remains an interesting and mostly unsolved problem.