Comparison of Optical OFDM and M-PAM for LED-Based Communication Systems
Comparison of Optical OFDM and M-PAM for LED-Based Communication Systems
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DOI：
10.1109/lcomm.2019.2891593
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发表时间：
2019-01
期刊：
影响因子：
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通讯作者：
Jie Lian;M. Noshad;M. Brandt-Pearce
中科院分区：
文献类型：
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作者：
Jie Lian;M. Noshad;M. Brandt-Pearce
基于发光二极管（LED）的通信，诸如可见光通信和红外通信，是提供短距离和高速数据传输的候选技术。在这封信中，$M$ -ary脉冲幅度调制（M-PAM），作为一种高带宽效率的方案，与三个著名的光正交频分复用（OFDM）方案进行了比较。考虑到LED的带宽限制和受限的峰值发射功率特性，比特加载算法和具有优化调制指数的单抽头均衡器被用于测试的光OFDM方案。为了减小信道带宽受限引起的码间干扰，对M-PAM系统采用了优化的脉冲波形和最小均方误差均衡器。从数值结果来看，M-PAM可以提供比OFDM更高的数据速率。当信道带宽与符号速率相比比较充裕时，光OFDM的性能优于M-PAM。
Light-emitting diode (LED)-based communications, such as visible light communications and infrared communications, are candidate techniques to provide short-range and high-speed data transmission. In this letter, $M$ -ary pulse amplitude modulation (M-PAM), used as a high bandwidth efficiency scheme, is compared with three well-known optical orthogonal frequency-division multiplexing (OFDM) schemes. Considering the bandwidth limit and constrained peak transmitted power characteristics of LEDs, a bit loading algorithm and a single-tap equalizer with an optimized modulation index are used for the optical OFDM schemes tested. To reduce the inter-symbol interference caused by the bandlimited channel, an optimized pulse shape and a minimum mean squared error equalizer are applied to the M-PAM system. From numerical results, M-PAM can provide a substantially higher data rate than OFDM for bandlimited channels. When the channel bandwidth is ample compared with the symbol rate, optical OFDM outperforms M-PAM.