With new frequency bands opening up, emerging wireless IoT devices are capitalizing on an increasingly divergent range of frequencies. However, existing coverage provisioning practice is often tied to specific standards and frequencies. There is little shareable wireless infrastructure for concurrent links on different frequencies, across networks and standards.

6G is on the horizon. A key paradigm being proposed for 6G involves a shift from device-centric to user-centric services, i.e., multiple devices collaborate to serve user demands. This paradigm shift and the potential applications require handling wireless signals from multiple sources collectively in a 3D space and potentially at close proximity to the end user. Conventional approaches of optimizing individual communication endpoints are ill-suited to collaborative 3D signal shaping. Recent smart surface proposals to program the radio environments appear a better fit, but existing designs implicitly require planar, rigid substrates. Optimizing 3D coverage would require very large surface implementations and incur many scalability and deployment challenges. In this paper, therefore, we propose a notion of metamorphic smart surfaces, i.e., shape-changing smart surfaces to cater to complex 3D propagation environments. Based on early explorations with HFSS simulations and two simple prototypes, we discuss the pros and cons of metamorphic surfaces and potential future directions.

Small IoT devices deployed in challenging locations suffer from uneven 3D coverage in complex environments. This work optimizes indoor coverage with LAVA, a Large Array of Vanilla Amplifiers. LAVA is a standard-agnostic cooperative mesh of elements, i.e., RF devices each consisting of several switched input and output antennas connected to fixed-gain amplifiers. Each LAVA element is further equipped with rudimentary power sensing to detect nearby transmissions. The elements report power readings to the LAVA control plane, which then infers active link sessions without explicitly interacting with the endpoint transmitter or receiver. With simple on-off control of amplifiers and antenna switching, LAVA boosts passing signals via multi hop amplify-and-forward. LAVA explores a middle ground between smart surfaces and physical-layer relays. Multi-hopping over short inter-hop distances exerts more control over the end-to-end trajectory, supporting fine-grained coverage and spatial reuse. Ceiling testbed results show throughput improvements to individual Wi-Fi links by 50% on average and up to 100% at 15 dBm transmit power (193% on average, up to 8x at 0 dBm). ZigBee links see up to 17 dB power gain. For pairs of co-channel concurrent links, LAVA provides average per-link throughput improvements of 517% at 0 dBm and 80% at 15 dBm.