在無線光通信非視線傳輸系統中使用多個光子量測器之接收分集技術

Receive Diversity with Multiple Photon-Counting Receivers in Non-Line-of-Sight Optical Wireless Communication

在紫外線非視線傳輸光通信系統中，為了增進接收信號之品質，我們提出了兩種接收分集架構，其中包括了一個光發射器與多個光子量測接收器。符元階層決策合成架構是基於硬式決策法則，每個光子量測接收器獨立做出決策並將其結果傳到共同的接收器。共同的接收器再根據多數法則做出最終的決策。第二種架構則是基於軟式決策法則，每個光子量測接收器將片元階層所收集到的數據直接傳送到共同的接收器。共同的接收器再根據這些傳送來的數據做出最終的決策。考慮M-ary脈波位置調變（MPPM）在布阿松統計特性之通道下，我們推導出上述兩種架構之符元錯誤率（SER），此外，我們利用電腦模擬在不同的環境下兩種架構之性能。模擬之結果證實了與傳統單一接收機系統比較起來，兩種架構均提供了可觀的性能增益。

To improve the received signal quality in ultraviolet non-line-of-sight optical communication channels, we propose two receive diversity schemes, one with a single optical transmitter and the other with multiple photon-counting receivers. The symbol-level decision fusion scheme is hard decision-based, and each photon-counting receiver sends its local decision to a common receiver. The common receiver makes a final decision according to the majority voting rule. Alternatively, the chip-level data fusion scheme is soft decision-based, and each local receiver sends its observed value directly to the common receiver. The common receiver combines these values and makes a final decision. We determine the symbol error rate of both schemes for m-ary pulse-position modulation using the Poisson channel statistic. Performance of both schemes under different scenarios was extensively evaluated using computer simulation. Simulation results demonstrated that compared with a conventional single-receiver system, both schemes exhibit considerable improvement in performance.