The popularity of concurrent transmissions (CT) has soared after recent studies have shown their feasibility on the four physical layers specified by BLE 5, hence providing an alternative to the use of IEEE 802.15.4 for the design of reliable and efficient low-power wireless protocols. However, to date, the extent to which physical layer properties affect the performance of CT has not yet been investigated in detail. This paper fills this gap and provides an extensive study on the impact of the physical layer on CT-based solutions using IEEE 802.15.4 and BLE 5. We first highlight through simulation how the impact of errors induced by relative carrier frequency offsets on the performance of CT highly depends on the choice of the underlying physical layer. We then confirm these observations experimentally on real hardware and with varying environmental conditions through an analysis of the bit error distribution across received packets, unveiling possible techniques to effectively handle these errors. We further study the performance of CT-based data collection and dissemination protocols in the presence of RF interference on a large-scale testbed, deriving insights on how the employed physical layer affects their dependability.

翻译：并发传输（CT）的可行性近期在BLE 5所规定的四种物理层上得到验证后，其关注度急剧上升，从而为设计可靠高效的低功耗无线协议提供了IEEE 802.15.4之外的替代方案。然而迄今为止，物理层特性对CT性能的影响程度尚未得到深入研究。本文填补了这一空白，系统研究了基于IEEE 802.15.4和BLE 5的CT物理层影响。我们首先通过仿真揭示：由相对载波频率偏移所引入的误差对CT性能的影响，高度依赖于所采用的底层物理层选择。随后通过分析接收数据包中的误码分布，在实际硬件及变化环境条件下对上述观察进行了实验验证，揭示了有效处理这些误差的可行技术。进一步地，我们在大规模测试平台上研究了射频干扰环境下基于CT的数据收集与分发协议性能，得出了关于所采用物理层如何影响协议可靠性的重要见解。