The main challenge in visible light communications (VLC) is the low modulation bandwidth of light-emitting diodes (LEDs). This forms a barrier towards achieving high data rates. Moreover, the implementation of high order modulation schemes is restricted by the requirements of intensity modulation (IM) and direct detection (DD), which demand the use of real unipolar signals. In this paper, we propose a novel amplitude, phase and quadrant (APQ) modulation scheme that fits into the IM/DD restrictions in VLC systems. The proposed scheme decomposes the complex and bipolar symbols of high order modulations into three different symbols that carry the amplitude, phase and quadrant information of the intended symbol. The constructed symbols are assigned different power levels and are transmitted simultaneously, i.e. exploiting the entire bandwidth and time resources. The receiving terminal performs successive interference cancellation to extract and decode the three different symbols, and then uses them to decide the intended complex bipolar symbol. We evaluate the performance of the proposed APQ scheme in terms of symbol-error-rate and achievable system throughput for different setup scenarios. The obtained results are compared with generalized spatial shift keying (GSSK). The presented results show that APQ offers a higher reliability compared to GSSK across the simulation area, while providing lower hardware complexity.

可见光通信 (VLC) 的主要挑战是发光二极管 (LED) 的低调制带宽。这形成了实现高数据速率的障碍。此外，高阶调制方案的实施受到强度调制 (IM) 和直接检测 (DD) 要求的限制，这需要使用真实的单极信号。在本文中，我们提出了一种新的幅度、相位和象限 (APQ) 调制方案，它适合 VLC 系统中的 IM/DD 限制。所提出的方案将高阶调制的复数和双极性符号分解为三个不同的符号，这些符号携带了预期符号的幅度、相位和象限信息。构造的符号被分配不同的功率电平并同时传输，即 充分利用整个带宽和时间资源。接收端执行连续干扰消除以提取和解码三个不同的符号，然后使用它们来决定预期的复双极符号。我们在不同设置场景的符号错误率和可实现的系统吞吐量方面评估了所提出的 APQ 方案的性能。将获得的结果与广义空间移位键控（GSSK）进行比较。所呈现的结果表明，与 GSSK 相比，APQ 在整个模拟领域提供了更高的可靠性，同时提供了更低的硬件复杂性。我们在不同设置场景的符号错误率和可实现的系统吞吐量方面评估了所提出的 APQ 方案的性能。将获得的结果与广义空间移位键控（GSSK）进行比较。所呈现的结果表明，与 GSSK 相比，APQ 在整个模拟领域提供了更高的可靠性，同时提供了更低的硬件复杂性。我们在不同设置场景的符号错误率和可实现的系统吞吐量方面评估了所提出的 APQ 方案的性能。将获得的结果与广义空间移位键控（GSSK）进行比较。所呈现的结果表明，与 GSSK 相比，APQ 在整个模拟领域提供了更高的可靠性，同时提供了更低的硬件复杂性。