多LED可见光定位通信一体化稳健功率分配

Robust Power Allocation for Multi-LED Integrated Visible Light Positioning and Communication

为了实现可见光定位(VLP)与可见光通信(VLC)一体化信号传输,保证稳健通信和有效定位,该文提出一种基于频分复用(FDM)的可见光定位通信一体化(VLPC)信号传输方案,并设计了一种多LED VLPC稳健功率分配方案。首先提出了一种基于频分复用的VLPC传输方案,实现两种信号一体化传输,频谱资源独立分配,从而降低传输时延,提高定位实时性;然后基于定位结果进行可见光信道估计,揭示了信道估计误差、通信速率与实际定位误差之间耦合关系与统计特性;更进一步,基于所得到的耦合关系,研究了多LED VLPC联合功率分配问题,从而最小化定位误差克拉默-拉奥下界(CRLB),并满足功率约束和通信速率中断概率约束,并利用半正定松弛、最差情况条件风险值和连续凸近似等方法,将难以求解的非凸问题转化为一系列凸半正定规划问题进行迭代求解,并获得高质量可行解;最后,经过数值仿真验证,所提出的方案能够同时实现稳健通信和有效定位。稳健传输速率超过350 Mbit/s,并且当最小速率门限为200 Mbit/s,最大中断概率门限为0.01时,在直射路径加散射路径场景中,可以实现厘米级定位。

In order to integrate signals of the Visible Light Positioning(VLP)and Visible Light Communication(VLC),a Frequency Division Multiplexing(FDM)based signal structure and a robust power allocation scheme for the multi-LED integrated Visible Light Position and Communication(VLPC)system are proposed.Firstly,an FDM-based VLPC signal structure is designed to carry two signals simultaneously with independent spectrum resource allocation,which can reduce transmission delay and improve real-time positioning.Then,the channel estimation based on positioning results is investigated,and the coupling relationship and statistical feature between the channel estimation error and positioning error are revealed.Furthermore,a VLPC robust power allocation problem is proposed to minimize the Cramér-Rao Lower Bound(CRLB)of the VLP under the power constraints and outage chance constraint of the communication rate.This nonconvex problem is transformed into a series of iterative convex semidefinite programming subproblems through semidefinite relaxation,worst-case conditional value-at-risk,and successive convex approximation.Finally,from the simulation results,it is verified that the proposed scheme can simultaneously achieve robust communication and effective positioning.The robust achievable rate exceeds 350 Mbit/s,and the centimeter-level positioning can still be achieved when the minimum rate requirement is 200 Mbit/s,and the maximum tolerable outage probability is 0.01.