Wi-Fi 6 beats 5G in the race to cut the cables from surgical navigation

Operating rooms are among the most technologically saturated spaces in medicine, yet many of the devices that surround the surgical table remain tethered to the wall by a web of cables and tubing. Those tangles are more than an aesthetic nuisance. Studies of operating room workflow have repeatedly identified cabling as a cause of trips and falls, detours, and heightened mental load for staff, particularly circulating nurses who must manoeuvre around obstacles in an already crowded space. In navigated surgery, where a tracking camera, a display and a planning workstation must all be connected to each other and often to a CT scanner, the problem is especially acute. A research team at RWTH Aachen University has now put two of the most promising wireless technologies, private 5G cellular networks and sixth-generation Wi-Fi, through a rigorous head-to-head test to determine whether either can finally cut the cord on surgical navigation.

The team, led by Noah Wickel and colleagues at the Chair of Medical Engineering, built a prototype wireless tracking system designed around the ISO/IEEE 11073 Service-oriented Device Connectivity standard, known as SDC. This interoperability standard, which has recently entered clinical use in patient monitoring for operating rooms and intensive care units, allows medical devices from different manufacturers to discover each other and exchange data over a network. The researchers mounted a surgical tracking camera, an embedded Linux computer, a lithium battery and power electronics on a mobile base with a medical holding arm, creating a self-contained unit that can run for more than 24 hours on a single charge. The embedded computer calculates surgical tool poses from the raw camera data and broadcasts them to navigation software over the network, using either a private 5G standalone network or an off-the-shelf Wi-Fi 6 router.

The choice of these two technologies reflects a broader debate in industrial and medical connectivity. Wi-Fi is cheap and ubiquitous, but its shared spectrum and collision-avoidance mechanisms make it difficult to guarantee the very low, bounded latencies that safety-critical applications demand. Fifth-generation cellular networks, by contrast, use licensed private spectrum and a strictly scheduled air interface, which has fuelled expectations that they could serve demanding medical control loops. The Aachen team operated their own private 5G campus network in the 3.7 to 3.8 GHz band licensed in Germany, running the open-source OpenAirInterface software for both the core network and the radio access network, connected to a low-power O-RAN radio unit over fibre. The tracking system was the only device on the network, giving 5G the most favourable possible conditions.

To measure end-to-end latency in a realistic way, the researchers devised an elegant experimental trick. The navigation computer controlled an infrared LED through a USB-to-serial adapter, and the tracking camera registered that LED as a fiducial marker. By timestamping the moment the LED was switched on and the moment the corresponding tracking message arrived at the navigation software, the team captured the entire acquisition and transmission chain, including the camera’s internal image processing that earlier measurements had omitted. Each configuration was measured for a full hour in an underground laboratory whose characteristics resemble a medium-sized operating room. As a benchmark for unimpeded surgical performance, the team adopted 100 milliseconds as an upper latency bound, drawing on studies of visual delay in laparoscopic and telesurgical settings showing that delays up to 100 milliseconds do not degrade task completion time or error rates, while longer delays double execution times and significantly increase errors.

The wired Ethernet baseline set a demanding standard. At a 100 Hz update rate, mean latencies of about 11 to 14 milliseconds were achieved with no packet loss, depending on whether the tracking system acted as the SDC provider sending reports or as a consumer triggering operations on the navigation computer. The Wi-Fi 6 configuration came remarkably close to this benchmark. At 50 Hz, mean latencies of 16.5 and 26.2 milliseconds were recorded in the conventional and reversed role set-ups respectively, with worst-case values of 36.7 and 97.2 milliseconds. Even at 100 Hz, the system operated without congestion or dropped messages, though maximum outliers grew larger. Crucially, the updated prototype consistently kept tracking events below 30 milliseconds on average and below 100 milliseconds in the worst case, a substantial improvement over the team’s earlier Wi-Fi 5 generation, which had shown unacceptable outliers exceeding 300 milliseconds.

The 5G results told a strikingly different story. Even at reduced update rates of 10, 20 and 50 Hz, the cellular link produced mean latencies roughly an order of magnitude higher than Ethernet, reaching 94.3 milliseconds at 10 Hz in the conventional configuration. Maximum delays approached 300 milliseconds, and at 100 Hz the system consistently descended into congestion, with messages arriving out of order, high drop rates of up to 16.85 percent, and subscription renewal failures that severed the SDC connection entirely. In the reversed role set-up, where the tracking system triggered operations on the navigation provider rather than streaming reports, the 5G link sustained 20 and 50 Hz without losses, but mean latencies of about 49 to 61 milliseconds still fell short of the Wi-Fi performance, and every 5G-based configuration saw at least one percent of data points arrive later than the critical 100-millisecond threshold.

Digging into the 5G uplink behaviour revealed why the cellular link struggled. In a series of controlled experiments using timestamped UDP packets, the researchers found that latency was highly sensitive to packet frequency: round-trip times changed little between 5 and 50 Hz but deteriorated sharply at 100 Hz and above. A clever mitigation strategy of bundling multiple tracking values into single packets, trading a small buffer delay for a lower packet rate, produced a remarkably stable transmission delay of 24 to 26 milliseconds and allowed simulated data rates of up to 800 Hz to be delivered within 45 milliseconds at the 99th percentile. That would be fast enough for the quickest clinical tracking systems on the market, which run at 400 to 500 Hz. However, maximum delays above 100 milliseconds reappeared whenever packet rates exceeded 20 Hz or background uplink traffic was present, underscoring the non-deterministic character of the link. Parallel downlink traffic was largely harmless, but even modest competing uplink traffic above 30 Mbit/s quickly congested the cell entirely.

The authors point to a likely culprit for the 5G shortcomings: the software-based radio access network. Their analysis of the literature shows that the OpenAirInterface implementation suffers from unpredictable jitter and frequent user-equipment disconnects, with comparable studies reporting outliers of 200 to 500 milliseconds, while alternative software stacks and dedicated hardware radio networks achieve far more stable results. The uplink also bears a structural handicap, since a device must first request a transmit grant from the network before sending, adding scheduling delay that downlink traffic avoids. Even so, neither the tested software radio network nor the dedicated hardware networks described in comparable studies currently meet the 3GPP standardisation target of 4 milliseconds user-plane latency, suggesting that the gap between cellular promise and surgical reality remains substantial.

The practical implications are significant. Wi-Fi 6, in this configuration, already delivers latencies compatible with the hand-eye coordination demands of navigated procedures such as neurosurgical spine instrumentation, meaning a wireless tracking camera could be prepped outside the sterile field, rolled in without cables, and repositioned freely to maintain line of sight to the instruments. That would ease set-up schedules, reduce trip hazards, and free mental capacity for the surgical team. Yet the researchers are careful not to write off 5G. Cellular networks handle dense user populations far better than Wi-Fi, and their behaviour in obstructed hospital environments remains an open question. Future work will explore higher 5G numerologies, pre-scheduled uplink grants, alternative radio network implementations, and deeper integration of SDC signalling into the 5G core, alongside Wi-Fi 7 features such as restricted target wake time that promise a further 30 percent latency reduction. For now, the cable-free operating room is closer than ever, and it will likely arrive first over Wi-Fi.

Subject of Research: Evaluation of 5G and Wi-Fi 6 wireless networks for latency-critical cable-free surgical navigation using the ISO/IEEE 11073 SDC standard

Article Title: Evaluation of 5G cellular and Wi-Fi 6 for cable-free surgical navigation using ISO/IEEE 11073 SDC

Article References: Wickel, N., Schollmaier, P., Radermacher, K., & Janß, A. (2026). Evaluation of 5G cellular and Wi-Fi 6 for cable-free surgical navigation using ISO/IEEE 11073 SDC. International Journal of Computer Assisted Radiology and Surgery. https://doi.org/10.1007/s11548-026-03774-1

Image Credits: AI Generated

DOI: 10.1007/s11548-026-03774-1

Keywords: 5G, Wi-Fi 6, surgical navigation, ISO/IEEE 11073 SDC, wireless medical devices, operating room, latency, tracking camera, private cellular networks, medical device interoperability, computer-assisted surgery, RWTH Aachen