Goldberg Hadar, Pinchas Monika
Department of Electrical and Electronic Engineering, Ariel University, Ariel 40700, Israel.
Entropy (Basel). 2020 Jun 26;22(6):708. doi: 10.3390/e22060708.
A single-input-multiple-output (SIMO) channel is obtained from the use of an array of antennas in the receiver where the same information is transmitted through different sub-channels, and all received sequences are distinctly distorted versions of the same message. The inter-symbol-interference (ISI) level from each sub-channel is presently unknown to the receiver. Thus, even when one or more sub-channels cause heavy ISI, all the information from all the sub-channels was still considered in the receiver. Obviously, if we know the approximated ISI of each sub-channel, we will use in the receiver only those sub-channels with the lowest ISI level to get improved system performance. In this paper, we present a systematic way for obtaining the approximated ISI from each sub-channel modelled as a finite-impulse-response (FIR) channel with real-valued coefficients for a 16QAM (16 quadrature amplitude modulation) source signal transmission. The approximated ISI is based on the maximum entropy density approximation technique, on the Edgeworth expansion up to order six, on the Laplace integral method and on the generalized Gaussian distribution (GGD). Although the approximated ISI was derived for the noiseless case, it was successfully tested for signal to noise ratio (SNR) down to 20 dB.
单输入多输出（SIMO）信道是通过在接收机中使用天线阵列获得的，其中相同的信息通过不同的子信道进行传输，并且所有接收到的序列都是同一消息的明显失真版本。目前，接收机不知道每个子信道的符号间干扰（ISI）水平。因此，即使一个或多个子信道会导致严重的ISI，接收机仍会考虑所有子信道的所有信息。显然，如果我们知道每个子信道的近似ISI，我们将在接收机中仅使用那些ISI水平最低的子信道，以提高系统性能。在本文中，我们提出了一种系统的方法，用于从每个被建模为具有实值系数的有限脉冲响应（FIR）信道的子信道中获取近似ISI，用于16QAM（16正交幅度调制）源信号传输。该近似ISI基于最大熵密度近似技术、高达六阶的埃奇沃思展开、拉普拉斯积分方法和广义高斯分布（GGD）。尽管该近似ISI是针对无噪声情况推导出来的，但它已成功地在低至20 dB的信噪比（SNR）下进行了测试。
