Opt Lett. 2018 Oct 15;43(20):4859-4862. doi: 10.1364/OL.43.004859.
A novel radio-over-fiber system with enhanced spectral efficiency is proposed by using a building-block-sparse-constellation-based orthogonal multiple access (BOMA) technique, and orthogonal frequency-division multiplexing with offset quadrature amplitude modulation (OFDM/OQAM) technique. With the help of BOMA, a user with good signal-to-noise ratio (SNR) can use the frequency band of a user with poor SNR to transmit extra information by sharing the same well-designed constellation. Moreover, the cycle prefix in OFDM is no longer required due to the properly designed prototype filters in OFDM/OQAM, contributing to maximum spectral efficiency (SE). To optimize transmission performance, four types of sparse constellations with different Euclidean distances between constellation points are designed. In our experiment, BOMA-OFDM/OQAM signals with a total net rate of 1.84 Gb/s and average SE of 4.6 bit/s/Hz are successfully transmitted over 25.2 km standard single-mode fiber for two users with wireless distances of 0.8 m and 0.3 m, respectively. Experimental results show that SE is increased by 37.7% compared with the traditional orthogonal frequency-division multiple access technique.
提出了一种基于分块稀疏星座的正交多址接入（BOMA）技术和带偏移正交幅度调制（OFDM/OQAM）技术的新型光纤无线电系统，提高了频谱效率。借助 BOMA，具有良好信噪比（SNR）的用户可以使用 SNR 较差的用户的频带通过共享相同设计良好的星座来传输额外信息。此外，由于 OFDM/OQAM 中设计了适当的原型滤波器，因此不再需要 OFDM 中的循环前缀，从而实现了最大频谱效率（SE）。为了优化传输性能，设计了四种具有不同星座点之间欧几里得距离的稀疏星座。在我们的实验中，成功地在两个无线距离分别为 0.8 m 和 0.3 m 的用户之间传输了总净速率为 1.84 Gb/s 且平均 SE 为 4.6 bit/s/Hz 的 BOMA-OFDM/OQAM 信号，距离为 25.2 km 的标准单模光纤。实验结果表明，与传统的正交频分多址技术相比，SE 提高了 37.7%。
