Sliced-LLDN: Hardware-Governed Deterministic Wireless Communication for Intra-Spacecraft and Intra-Launcher Applications

Abstract

Wireless sensor networks can reduce the mass and integration complexity of spacecraft and launch vehicle harnesses, yet existing flight-heritage implementations do not meet the determinism required by attitude control loops and launcher functional chains. This article presents Sliced-LLDN, a wireless sensor network protocol that binds MAC processing, radio access, upper-layer data handling, and sensor sampling to a single hardware-governed timeline. The protocol modifies the IEEE 802.15.4e LLDN MAC, operates over an impulse radio ultra-wideband physical layer, and is implemented bare-metal on a ZYNQ System-on-Chip platform. Each 1.0 ms timeslot is subdivided into hardware-timed slices to which all in-slot processes are pinned, yielding data latency that is constant rather than merely bounded and supporting up to five sensor nodes within a 10 ms superframe. Two data acquisition modes are formalized: synchronous sampling for network-wide time-aligned measurements and uniform-latency sampling for slot-position-independent sub-millisecond delivery. Experimental evaluation on a four-node network demonstrates timestamping accuracy within $\pm 4~\mu $ s, synchronous sampling accuracy within $\pm 2~\mu $ s, per-node latency of approximately $930~\mu $ s in uniform-latency mode, RMS jitter below $1.1~\mu $ s, and zero packet loss over one million superframes per node. These results satisfy the timing requirements of spacecraft attitude and orbit control systems and a subset of launch vehicle requirements.