密集阵列可见光通信系统多域协作的调制多址技术研究

Visible light communication (VLC) technology uses dense LED array as a natural data transmitter to support high-rate wireless transmission and thus, has been considered as a promising technological candidate for indoor high-rate high-density wireless network. However, due to the intensity modulation and direct detection of VLC, its transmitted signal and channel coefficients are non-negative real-valued numbers. For this reason, the equivalent channe matrix of multiuser VLC systems based on dense LED array is usually highly rank-deficient. In addition, when we design the transmitted signals for VLC, we must consider the constraints from both sufficient illumination and reliable communications. Consequently, for the transmission of dense array VLC multiuser systems, we can not straightforwardly follow the well-established theory and techniques for multiuser radio frequence wireless communications. Therefore, to solve the above-mentioned problems, this application first investigates the management techniques of inter-user interference based on the user-domain space-time collaboration to establish a general uniquely identificable space-time constellation structure for the highly rank-deficient nonnegative channels. With this, we take advantage of the Frobenius norm theory to attain the best tradeoff region of illumination and communication, and, then, design the energy-efficient space-time signals for the dense array multiuser visible light communication systems. Then, based on the additively uniquely decomposable constellation group theory, we consider the energy-efficient modulation division scheme with low-complexity detection. Through the deep investigation of the application, we aim at providing a theoretical base for the dense array multiuser visible light communication systems and modulation division methods with practical applications.

室内可见光通信利用密集LED阵列作为发射终端，具有实现高速传输的天然优势，被视为室内高速高密度无线网络的优选技术之一。然而，可见光通信采用强度调制能量检测方式，信号及信道系数均为非负实数，其多用户等效信道矩阵高度缺秩，且信号传输要兼顾照明需求。因此，密集阵列可见光通信多用户中的高效传输无法直接袭用多用户无线电通信中的现有理论和方法。针对上述问题，本项目首先研究基于用户域空时协作的多用户干扰管理策略，建立实现高度缺秩非负信道中实现空时信号唯一可辨识的高效空时星座结构。在此基础上，基于Frobenius矩阵范数理论求解舒适照明与可靠通信的有效折中区域，进一步设计融合照明与通信的高效空时传输信号。最后，研究实现加性唯一可分解的空时映射方案，并设计基于用户域空时协作的高效调制分多址及其低复杂度检测算法。通过深入研究，本项目力求为室内密集阵列多用户可见光通信高效传输提供理论依据和技术支撑。

本项目围绕如何利用泛在的照明阵列实现可见光通信高速传输等关键科学问题，主要研究了以下内容：（1）实高度缺秩非负信道中实现空时信号唯一可辨识的高效空时星座结构；（2）设计融合照明与通信的效空时传输信号；（3）研究高效调制分多址及其低复杂度检测算法。通过深入研究。通过持续研究，本项目建立了阵列可见光通信内生关联传输理论，发现了实现内生关联特性的传输结构，设计了高效的空间关联传输方法。具体包括以下三个方面结果：（1）针对阵列传输中的低复用增益和阵列信道信息难以获取的问题，揭示了阵列可见光通信系统所独有的内生关联特性：阵列可见光通信只需要知道有限状态信道信息就可以实现最大复用增益。围绕该发现形成了指导阵列可见光通信实现高速传输的内生关联传输理论。（2）发现了实现阵列可见光通信内生关联的最优传输结构。在内生关联特性的基础上，通过优化求解得到了实现最优复用增益的传输结构：传输信号在空间维度上实现关联，满足加性唯一可分解特性。该成果为破解阵列可见光通信高速传输难题指明了实现的途径，为有效解决密集场景中的自适应全分集传输问题提供了具体传输结构。（3）构建了阵列可见光通信实现高效传输的空间关联方法。 基于加性唯一可辨识星座理论框架，提出了全速率内生关联传输技术方案。项目实施期间，在IEEE Journal on Selected Areas in Communications、IEEE Transactions on Wireless Communications、IEEE Transactions on Communications、IEEE Transactions on Information Theory等权威期刊发表学术论文18篇，出版学术专著2部，指导研究生16人次，获得河南省自然科学三等奖1项。