LED luminaries are now deployed densely in indoor areas to provide uniform illumination. Visible Light Communication (VLC) can also benefit from this dense LED infrastructure. In this paper, we propose DenseVLC, a cell-free massive MIMO networking system enabled by densely distributed LEDs, that forms different beamspots to simultaneously serve multiple receivers. This is a cell-free system, as there is no notion of autonomous cells and transmitters cooperate to jointly serve the users. Given a power budget for communication, DenseVLC assigns the power budget among the distributed LEDs to optimize the system throughput and user fairness. We formulate an optimization problem to derive the optimal policy for the power allocation. Our insights from the optimal policies allow us to simplify DenseVLC’s system design and propose a heuristic algorithm that can reduce the complexity by 99.96%. Besides, we propose a novel synchronization method using non-line-of-sight VLC to synchronize all the transmitters that will form a beamspot to serve the same receiver. We implement DenseVLC with off-the-shelf devices, solve practical challenges in the system design, and evaluate it with extensive and realistic experiments in a system of 36 transmitters and 4 receivers in an area of $3\:\text{m}\,\,\times 3\:\text{m}$ . Our results show that DenseVLC can improve the average system throughput by 45%, or improve the average power efficiency by 2.3 times, while maintaining the requirement for uniform illumination. Finally, we demonstrate that DenseVLC is robust against blockage.

中文翻译：

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无可见光的无单元网络系统

现在，LED灯具密集地部署在室内区域，以提供均匀的照明。可见光通信（VLC）也可以从这种密集的LED基础设施中受益。在本文中，我们提出了DenseVLC，这是一种由密集分布的LED组成的无单元大规模MIMO网络系统，它形成不同的波束斑，同时为多个接收器提供服务。这是一个无蜂窝系统，因为没有自治蜂窝的概念，并且发射机合作共同为用户服务。给定用于通信的功率预算，DenseVLC在分布式LED之间分配功率预算，以优化系统吞吐量和用户公平性。我们制定了一个优化问题，以得出功率分配的最优策略。我们从最佳策略中得出的见解使我们能够简化DenseVLC的系统设计，并提出一种启发式算法，可以将复杂度降低99.96％。此外，我们提出了一种新颖的同步方法，该方法使用非视距VLC来同步将形成波束斑的所有发射机以为同一接收机提供服务。我们使用现成的设备来实现DenseVLC，解决系统设计中的实际挑战，并在一个由36个发射器和4个接收器组成的系统中，通过大量实际的实验对其进行评估。 $ 3 \：\ text {m} \，\，\ times 3 \：\ text {m} $ 。我们的结果表明，DenseVLC可以将平均系统吞吐量提高45％，或将平均功率效率提高2.3倍，同时保持对均匀照明的要求。最后，我们证明DenseVLC具有强大的抗阻塞能力。