Interference as Noise: Friend or Foe?
Interference as Noise: Friend or Foe?
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DOI：
10.1109/tit.2016.2553098
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发表时间：
2016-06-01
影响因子：
2.5
通讯作者：
Devroye, Natasha
中科院分区：
文献类型：
--
作者：
Dytso, Alex;Tuninetti, Daniela;Devroye, Natasha
本文展示了两个用户,高斯干扰信道(G-IC)治疗干扰噪声没有时间分享(TINnoTS)达到关闭能力区域在一个恒定的差距,或在一个空白订单的O (log (ln (min (S I)) /γ))一组的勒贝格测度γ的成分(0,1),S是最大的信噪比直接联系,我是最大的干扰噪声比在十字架上链接。因此，从广义自由度（gDoF）的角度来看，TINnoTS对除零测量子集外的所有信道增益都是最优的。已知具有高斯输入的TINnoTS在弱干扰区域的子集中在1/2位内是最佳的。令人惊讶的是，本文表明TINnoTS在所有参数域中都是gof最优的，即使在高斯输入的联合解码是最优的强和很强的干扰域中也是如此。对于TINnoTS在所有参数范围内的近似最优性，使用非高斯输入至关重要。因此，本文建议使用混合输入作为G-IC的通道输入，其中混合输入是离散和高斯随机变量的和。有趣的是，参考Han-Kobayashi可实现方案，混合输入的离散部分在某种意义上表现为有效的公共信息，尽管被视为噪声，但其对可实现速率区域的影响就像它在非预期的接收器上与期望的信息一起被解码一样。实际含义是，离散干扰输入是朋友，而高斯干扰输入通常是敌人。本文还讨论了混合输入的TINnoTS方案的其他实际意义。由于TINnoTS既不需要显式联合解码，也不需要时间共享，因此本文的结果适用于各种无关或异步信道，例如块异步G-IC（不是信息稳定信道）和在一个或多个接收器处具有部分码本知识的G-IC。
This paper shows that for the two-user Gaussian interference channel (G-IC) treating interference as noise without time sharing (TINnoTS) achieves the closure of the capacity region to within either a constant gap, or to within a gap of the order O(log(ln(min(S, I))/gamma)) up to a set of Lebesgue measure gamma is an element of (0, 1], where S is the largest signal to noise ratio on the direct links and I is the largest interference to noise ratio on the cross links. As a consequence, TINnoTS is optimal from a generalized degrees of freedom (gDoF) perspective for all channel gains except for a subset of zero measure. TINnoTS with Gaussian inputs is known to be optimal within 1/2 bit for a subset of the weak interference regime. Rather surprisingly, this paper shows that TINnoTS is gDoF optimal in all parameter regimes, even in the strong and very strong interference regimes where joint decoding of Gaussian inputs is optimal. For approximate optimality of TINnoTS in all parameter regimes, it is critical to use non-Gaussian inputs. This paper thus proposes to use mixed inputs as channel inputs for the G-IC, where a mixed input is the sum of a discrete and a Gaussian random variable. Interestingly, with reference to the Han-Kobayashi achievable scheme, the discrete part of a mixed input is shown to effectively behave as a common message in the sense that, although treated as noise, its effect on the achievable rate region is as if it were jointly decoded together with the desired messages at a non-intended receiver. The practical implication is that a discrete interfering input is a friend, while an Gaussian interfering input is in general a foe. This paper also discusses other practical implications of the proposed TINnoTS scheme with mixed inputs. Since TINnoTS requires neither explicit joint decoding nor time sharing, the results of this paper are applicable to a variety of oblivious or asynchronous channels, such as the block asynchronous G-IC (which is not an information stable channel) and the G-IC with partial codebook knowledge at one or more receivers.