Adaptive modulation in MIMO optical wireless communication systems  

多输入多输出无线光通信系统中的自适应调制技术（英文）

作　　者：吴斌[1] 吴亮[1] 邹采荣[1] 

机构地区：[1]东南大学信息科学与工程学院,南京210096

出　　处：《Journal of Southeast University(English Edition)》2015年第2期175-180,共6页东南大学学报（英文版）

基　　金：The National High Technology Research and Development Program of China(863 Program)(No.2013AA013601);the National Science and Technology M ajor Project of China(No.2015ZX03004009)

摘　　要：In the intensity modulation and direct detection （IM/DD） multiple-input multiple-output （MIMO） optical wireless communication systems, a direct-current-biased adaptive modulation scheme is proposed to guarantee the nonnegative property of transmitted signals, and the MIMO channel is converted to a parallel channel by using a singular value decomposition. Besides, a QR decomposition and successive interference cancellation based adaptive modulation scheme is proposed, and the MIMO channel can be simplified to a parallel channel under the bit error ratio （BER） target constraint. The power is optimally allocated to each sub-channel to maximize the data rate. Simulation results show that the proposed adaptive modulation schemes can effectively improve the transmission rate of the systems under the BER target and constant optical power constraints. The proposed adaptive modulation schemes make use of the multiplexing gain of the MIMO techniques, and can further improve the spectrum efficiency of optical wireless systems.在基于强度调制、直接检测的多输入多输出无线光通信系统中,为了保证发射信号非负特性,提出一种基于直流偏置的自适应调制技术,并且利用奇异值分解将多输入多输出信道转换为并行信道.此外,提出一种基于QR分解、逐次干扰消除的自适应调制技术.在目标误比特率性能条件下,利用QR分解、逐次干扰消除的特性将多输入多输出信道等效为并行信道.根据最大化可达速率的优化目标,最优地给各个子信道分配功率.仿真结果表明所提出的2种自适应调制方法在保证误比特率性能和平均发射光功率恒定的前提下,有效地提高了系统的传输速率.这2种自适应调制技术在利用多输入多输出技术空分复用增益的同时,进一步提高了无线光通信系统的频谱利用率.

关 键 词：optical wireless communication multiple inputand multiple output （MIMO） adaptive modulation 

分 类 号：TN92[电子电信—通信与信息系统]