Visible light communication (VLC) is seen as a potential access option for fifth-generation (5G) wireless communication (Wang et al., 2014) and (Ayyash et al., 2016) and beyond 5G (Strinati et al., 2019). A reliable VLC system benefits from an accurate estimate of the receiver’s position and orientation. In many cases, the orientation of the receiver is estimated with an external orientation estimation device. However, these devices generally suffer from drift and misalignment, causing an uncertainty in the orientation presented to the receiver. Hence, the external device can only provide a probability distribution of the orientation to the position estimator, which can be used as prior information for the position estimation. Since the orientation of a receiver greatly affects the performance of a visible light system, the orientation uncertainty will degrade the performance of standard positioning algorithms, implying it should be taken into account when designing a robust positioning algorithm. In this paper, we design an received signal strength (RSS)-based hybrid position and orientation estimation algorithm using the hybrid maximum likelihood (ML)/maximum a posteriori (MAP) (HyMM) principle for a multiple LEDs - multiple photodiodes (PDs) (MLMP) system to take into account the presence of prior information on the orientation. The proposed HyMM estimator is compared with three existing estimators, i.e., the simultaneous position and orientation (SPO) estimator, the misspecified maximum likelihood (MML) estimator and the first-order-approximation-based positioning algorithm, subject to the orientation uncertainty. Further, in order to analytically assess the performance of the proposed estimator, the theoretical lower bound on the mean squared error (MSE), i.e. the hybrid Cramér-Rao bound (HCRB) for HyMM is derived. Computer simulations show an asymptotic tightness between the performance of the estimator and its associated theoretical lower bound.

中文翻译：

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存在方向先验信息的可见光系统的混合位置和方向估计


可见光通信 (VLC) 被视为第五代 (5G) 无线通信（Wang 等人，2014 年）和（Ayyash 等人，2016 年）以及 5G 之外的潜在接入选项（Strinati 等人，2019 年） 。可靠的 VLC 系统受益于对接收器位置和方向的准确估计。在许多情况下，接收器的方向是使用外部方向估计设备来估计的。然而，这些设备通常会遭受漂移和未对准的影响，从而导致接收器呈现的方向不确定。因此，外部设备只能向位置估计器提供方向的概率分布，其可以用作位置估计的先验信息。由于接收器的方向极大地影响可见光系统的性能，因此方向不确定性会降低标准定位算法的性能，这意味着在设计鲁棒定位算法时应考虑到这一点。在本文中，我们使用混合最大似然 (ML)/最大后验 (MAP) (HyMM) 原理为多个 LED - 多个光电二极管 (PD) 设计基于接收信号强度 (RSS) 的混合位置和方向估计算法（MLMP）系统考虑到先验信息的存在。将所提出的 HyMM 估计器与三种现有估计器进行比较，即同时位置和方向（SPO）估计器、错误指定最大似然（MML）估计器和基于一阶近似的定位算法，受方向不确定性的影响。此外，为了分析评估所提出的估计器的性能，均方误差（MSE）的理论下界，即 推导出 HyMM 的混合 Cramér-Rao 界 (HCRB)。计算机模拟显示估计器的性能与其相关的理论下限之间存在渐近紧密性。