研究了N+1用户、1 × N单输入多输出(SIMO)高斯干扰信道,其中每个发射机有一个单天线,每个接收机有N个天线。O(1)内的对称容量针对对称情况来表征,其中所有直接链路具有相同的信噪比(SNR),并且所有不期望的链路具有相同的干扰噪声比(INR)。精确容量的间隙是一个常数,与SNR和INR无关。为了得到这一结果,我们首先推广了由El Gamal和Costa引入的确定性干扰信道来建模具有多个天线的干扰信道。我们推导出这种确定性干扰信道的容量区域。基于确定性信道提供的见解,我们描述了高斯情况下的广义自由度(GDOF),这直接导致O(1)的容量近似。在可扩展性方面,一个有趣的结论是,在N+1用户、1 × N SIMO情况下,发现将干扰视为噪声的广义自由度(GDOF)机制在2用户干扰信道中是最优的。在相反的方面,新的多用户外部边界出现在这项工作中,并不直接遵循2用户的情况。除了GDOF区域之外,外部边界还标识了建立容量区域的强干扰机制。
英文摘要:
The N+1 user, 1 x N single input multiple output (SIMO) Gaussian interference channel where each transmitter has a single antenna and each receiver has N antennas is studied. The symmetric capacity within O(1) is characterized for the symmetric case where all direct links have the same signal-to-noise ratio (SNR) and all undesired links have the same interference-to-noise ratio (INR). The gap to the exact capacity is a constant which is independent of SNR and INR. To get this result, we first generalize the deterministic interference channel introduced by El Gamal and Costa to model interference channels with multiple antennas. We derive the capacity region of this deterministic interference channel. Based on the insights provided by the deterministic channel, we characterize the generalized degrees of freedom (GDOF) of Gaussian case, which directly leads to the O(1) capacity approximation. On the achievability side, an interesting conclusion is that the generalized degrees of freedom (GDOF) regime where treating interference as noise is found to be optimal in the 2 user interference channel, does not appear in the N+1 user, 1 x N SIMO case. On the converse side, new multi-user outer bounds emerge out of this work that do not follow directly from the 2 user case. In addition to the GDOF region, the outer bounds identify a strong interference regime where the capacity region is established.
In the two-user Gaussian interference channel with Gaussian inputs and treating interference as noise (TIN), improper complex signals can be beneficial if time-sharing is not allowed or if only the data rates are averaged over several transmit strategies (convex hull formulation). On the other hand, proper (circularly symmetric) signals have recently been shown to be optimal if coded time-sharing is considered, i.e., if both the data rates and the transmit powers are averaged. In this paper, we show that both conclusions remain the same if single-input multiple-output (SIMO) systems with multi…
The scaling of coherent and non-coherent channel capacity is studied in a single-input multiple-output (SIMO) block Rayleigh fading channel as both the bandwidth and the number of receiver antennas go to infinity jointly with the transmit power fixed. The transmitter has no channel state information (CSI), while the receiver may have genie-provided CSI (coherent receiver), or the channel statistics only (non-coherent receiver). Our results show that if the available bandwidth is smaller than a threshold bandwidth which is proportional (up to leading order terms) to the square root of the numbe…
In this paper, we derive the error vector magnitude (EVM) in a selection combining (SC) system experiencing co-channel interference, for arbitrary number of antennas and interferers when all the channels experience Rayleigh fading. We use a novel approach that uses the CCDF of SIR to derive EVM as using the conventional approach to derive EVM for a SC system is difficult. Considering two selection rules based on (a) maximum signal power (b) maximum signal to interference ratio, we observe that EVM is worse when maximum signal power based rule is used. Further, EVM is also derived considering (…
Quasi-Static SIMO Fading Channels at Finite Blocklength
我们研究了在准静态单输入多输出(SIMO)衰落信道下,给定块长和错误概率的最大可达速率。在温和的条件下的信道增益,它示出了信道色散是零,无论是否衰落实现在发射机和/或接收机。结果如下从计算和分析听话的逆和可扩展性的界限。通过数值计算,我们验证,在某些情况下,零色散确实需要快速收敛到中断容量的块长度的增加。在特定的1*2 SIMO Rician信道的示例中,与具有相同容量的AWGN信道所需的块长度相比,实现90%容量所需的块长度大约小一个数量级。
We derive inner and outer bounds on the capacity region for a class of three-user partially connected interference channels. We focus on the impact of topology, interference alignment, and interplay between interference and noise. The representative channels we consider are the ones that have clear interference alignment gain. For these channels, Z-channel type outer bounds are tight to within a constant gap from capacity. We present near-optimal achievable schemes based on rate-splitting and lattice alignment.
We obtain new sum capacity results for the Gaussian many-to-one and one-to-many interference channels in channel parameter regimes where the sum capacity was known only up to a constant gap. Simple Han-Kobayashi (HK) schemes, i.e., HK schemes with Gaussian signaling, no time-sharing, and no common-private power splitting, achieve sum capacity under the channel conditions for which the new results are obtained. To obtain sum capacity results, we show that genie-aided upper bounds match the achievable sum rate of simple HK schemes under certain channel conditions.
Previous works established the capacity region for some special cases of discrete memoryless degraded cognitive interference channel (CIC) with unidirectional destination cooperation (UDC). In this letter, we characterize the capacity region of the general discrete memoryless degraded CIC-UDC. The obtained results imply that the capacity region is achieved by the Gel'fand-Pinsker coding at the cognitive transmitter, superposition coding at the primary transmitter and decode-and-forward at the relay. Furthermore, using this general result and a novel converse analysis, we establish the capacity…
The Interference Channels (ICs) represent fundamental building blocks of wireless communication networks. Despite considerable progress in network information theory, available capacity results for ICs, specifically those with more than two users, are still very limited. One of the main difficulties in the analysis of these networks is how to establish useful capacity outer bounds for them. In this paper, novel techniques requiring subtle sequential application of Csiszar-Korner identity are developed to establish efficient single-letter outer bounds on the sum-rate capacity of interference ne…