Start of frame delimiter (SFD) is of critical importance for frame synchronization of packet communication systems. IEEE 802.15.4f defines the SFD as a 16-bit binary sequence and defines the preamble as a 16-bit alternating $\{+1,-1,\ldots, +1,-1\}$ sequence. In addition, direct current (DC) balance is important and always preferred in circuit design. With respect to the preamble and the DC balance constraints, in this letter, we study the performance bound of frame synchronization via SFD. We provide a mathematical modeling of SFD and show that for any SFD, the strongest side lobe yielded can never be less than 2, regardless of the lengths of the SFD and the preamble. As a special case of the more general case considered in this letter, the SFDs in 802.15.4f, achieves the performance bound for synchronization accuracy.

中文翻译：

---

帧分隔符开始的性能界限

帧起始定界符 (SFD) 对分组通信系统的帧同步至关重要。IEEE 802.15.4f 将 SFD 定义为 16 位二进制序列，并将前导定义为 16 位交替 $\{+1,-1,\ldots, +1,-1\}$ 序列。此外，直流 (DC) 平衡很重要，并且在电路设计中始终是首选。关于前导码和 DC 平衡约束，在这封信中，我们研究了通过 SFD 进行帧同步的性能界限。我们提供了 SFD 的数学模型，并表明对于任何 SFD，产生的最强旁瓣永远不会小于 2，无论 SFD 和前导码的长度如何。作为这封信中考虑的更一般情况的特例，802.15.4f 中的 SFD 实现了同步精度的性能限制。