Building Intelligent and Interoperable Smart Homes with Wi-Fi 7

Today’s smart homes are more complex than ever before — many households now support more than 50 wireless devices. Thermostats, cameras, door locks, and appliances compete for airtime with smartphones, tablets, and gaming consoles across congested 2.4- and 5-GHz Wi-Fi bands. Overlapping networks from adjacent residences add interference and contention, reducing throughput, destabilizing connections, and increasing battery drain.

Setting up and managing smart home devices can also be frustrating for users. The average U.S. household has three users setting up, managing, and controlling their smart home devices. A smart TV, dishwasher, and door lock may be controlled through separate manufacturer apps, often with different setup and control methods.

At the same time, smart home devices are evolving beyond simple connectivity as AI transforms user experiences. Devices now incorporate voice, vision, and wireless sensing capabilities, placing new demands on wireless platforms. Cameras run AI-based object recognition, thermostats adapt to occupancy patterns, and door locks authenticate entry using precise wireless ranging.

Beyond higher throughput, these systems require contextual sensing, coordinated power management, and interoperability across wireless protocols.

Optimized for IoT Devices: Wi-Fi 7 for IoT

Wi-Fi standards have historically evolved to deliver higher peak throughput and greater network capacity. Wi-Fi 7 introduces several high-performance features, including 4096-QAM modulation, 320-MHz channels, and simultaneous multi-link operation across radios. These capabilities primarily target access points (APs) and high-throughput clients such as laptops, gaming consoles, and augmented- or virtual-reality devices.

IoT devices operate under different constraints than high-bandwidth clients. They typically use only a single antenna, must support multi-year battery life, and operate in 20-MHz-wide channels while transmitting and receiving small, intermittent payloads. The wide channel bandwidths of Wi-Fi 7 provide limited benefit for low-data-rate IoT traffic while increasing RF and baseband complexity, cost, and power consumption.

To address these requirements, the Wi-Fi Alliance introduced Wi-Fi 7 certification for 20-MHz-only station devices in January 2026. This specification allows IoT devices to maintain narrowband operation while supporting Wi-Fi 7 MAC-layer innovations such as multi-link operation (MLO), multiple resource units (MRUs), and restricted target wake time (R-TWT).

For example, Infineon’s AIROC ACW741x, the first Wi-Fi 7 device designed for IoT applications, implements MLO using a multi-link single radio (MLSR) architecture with adaptive band switching. A single RF chain maintains logical associations across the 2.4-, 5-, and 6-GHz bands and transitions efficiently between them. When congestion or interference affects one band, the device automatically switches to a cleaner band.

Compared with fixed-band Wi-Fi 6 designs, this approach improves link reliability by up to 3X without additional hardware or power overhead.

Low Power for IoT

In the smart home, low-power operation is essential for battery-powered accessories such as cameras and smart door locks. Wi-Fi sleep and standby power are critical for minimizing battery consumption when devices aren’t actively transmitting or receiving data from a Wi-Fi access point.

The ACW741x family achieves 70-µW Wi-Fi connected standby power at DTIM10, approximately 15X lower than comparable devices. Bluetooth-connected idle power measures 120 µW, roughly 8X lower than competing devices, while active Wi-Fi receive power is 59 mW, about 3X lower. A smart door lock using the ACW741x and four AA batteries, with 10 access events per day, can operate for more than three years, about two years longer than today’s competing solutions.

Additional Wi-Fi 7 MAC-layer mechanisms implemented in the ACW741x further improve IoT traffic efficiency. For example, MRU extends orthogonal frequency-division multiple access (OFDMA) by allowing a device to occupy multiple non-contiguous resource units within a single transmission opportunity. For the short, burst-oriented packets typical of IoT traffic, this improves spectrum utilization and reduces latency, particularly when interference affects portions of the channel.

R-TWT, also implemented in the ACW741x, coordinates groups of IoT devices into shared, scheduled wake windows based on traffic characteristics and latency requirements. Instead of independently negotiated wake schedules that increase contention, the access point centrally schedules transmissions. Devices remain in deep sleep longer and wake during protected transmission windows, reducing collisions in dense networks.

Interoperability: Matter, Thread, and Tri-Radio Smart Home Platforms

Smart home interoperability has historically been fragmented. Devices from different manufacturers often rely on incompatible protocols and require proprietary hubs or gateways for communication. The Matter standard addresses this issue by defining a common IP-based application layer that operates over Wi-Fi and the IEEE 802.15.4 Thread protocol, allowing products from different vendors to discover, commission, and control one another.

Thread provides low-power wireless transport for many battery-operated Matter devices. Built on IEEE 802.15.4, it forms a self-healing mesh network that connects sensors, switches, and other constrained nodes while maintaining native IP connectivity. Multi-hop mesh routing extends coverage throughout the home without increasing device transmit power.

The Infineon ACW741x integrates Wi-Fi 7, Bluetooth Low Energy, and IEEE 802.15.4/Thread in a tri-radio SoC with full Matter support. Wi-Fi brings high-throughput connectivity to the home network and cloud services, Thread connects low-power mesh nodes, and Bluetooth supports device onboarding and Wi-Fi provisioning.

Smart home appliances with Thread Border Router functionality connect Thread devices to the Wi-Fi network. Refrigerators, ovens, or washing machines equipped with the ACW741x can route Thread traffic from battery-powered sensors while maintaining Wi-Fi connectivity to cloud services and mobile applications. In this configuration, the appliance becomes part of the home’s network infrastructure rather than simply another endpoint.

Tri-band Wi-Fi operation offers additional advantages for kitchen appliances that encounter interference from microwave ovens operating in the 2.4-GHz band. Adaptive band switching allows devices to migrate to 5- or 6-GHz channels when interference occurs, maintaining reliable connectivity. Low standby power during DTIM (delivery traffic indication map) sleep intervals also supports compliance with emerging EU regulations that impose near-zero standby power limits on connected appliances.

Intelligence: Sensing the Environment Without Dedicated Hardware

Many smart home devices monitor their physical surroundings and execute control decisions at the edge to reduce latency and enable real-time user experiences. Wi-Fi channel state information (CSI) can detect motion in the environment by analyzing how Wi-Fi signals propagate within an environment.

CSI captures variations in signal propagation, making it possible for systems to infer presence, occupancy, and motion without specialized hardware or additional sensors. The ACW741x enables CSI exchange between Wi-Fi devices to support this sensing capability.

Smart thermostats use CSI measurements to detect room occupancy and adjust HVAC operation. They activate when people enter and suspend operation when the space is empty.

Unlike passive infrared sensors, which require line of sight and often fail to detect stationary occupants, CSI sensing operates through walls and, when combined with AI at the edge or in the cloud, can detect subtle motion patterns. The same sensing data can also trigger broader automation sequences, such as activating lights and audio when someone enters a room or alerting users when someone approaches the front door.

While Wi-Fi CSI enables environmental sensing, other smart home applications require precise device-to-device ranging for proximity-based actions. Bluetooth Channel Sounding measures the phase and time of flight of Bluetooth signals with centimeter-level accuracy for device authentication and keyless entry.

Channel Sounding significantly improves security compared with RSSI-based proximity detection used in legacy smart locks, where signal strength can be manipulated or spoofed. In door-lock applications, it enables keyless entry by activating only when an authenticated device is within a defined range, reducing the risk of relay attacks. Between access events, Bluetooth LE remains in a low-power idle and advertising state, helping extend battery life.

By integrating Bluetooth Channel Sounding alongside Wi-Fi CSI, the ACW741x supports both ranging and environmental sensing. Together, these techniques enable local detection of presence, motion, and proximity without dedicated sensing hardware or cloud processing.

Conclusion

Smart home systems require wireless platforms that do more than connect devices. They must sense their physical environment, maintain low-power connectivity in congested deployments, and interoperate seamlessly across protocols and vendors.

Devices like the AIROC ACW741x address these requirements. The 20-MHz tri-radio system-on-chip (SoC) integrates Wi-Fi 7 (802.11be), Bluetooth Low Energy with Channel Sounding (Core spec 6.0), and IEEE 802.15.4/Thread with Matter support in a single chip. This architecture ushers in three key capabilities for modern smart home systems: intelligence, efficiency, and interoperability.