The Office for Interoperability and Compatibility (OIC) is an S&T technology center that ensures first responders and DHS programs can exchange voice, video and data across any network. OIC develops interoperability requirements, standards coordination, R&D/testing and real‑world evaluations, validates nonproprietary capabilities for procurements, runs pilot projects, and advises S&T programs on resilient network solutions (e.g., small cells, FirstNet, private networks, satellite) to keep responders connected.
Direct‑to‑cell (D2C) satellites act like cellular base stations in space: an LEO satellite’s large phased‑array antennas receive/transmit signals from ordinary unmodified phones, relay them via gateways into a partner mobile operator’s network, and backhaul over inter‑satellite links or ground stations. Limitations operators should expect: higher per‑user/service cost and subscription/partnering fees; finite shared bandwidth and cell capacity (providers advertise tens to ~120 Mbps per space‑cell in commercial designs); increased propagation delay and Doppler effects (LEO adds tens of milliseconds and requires gateway compensation); device and spectrum compatibility and regulatory coordination; and lower aggregate capacity and higher per‑bit cost than dense terrestrial networks.
Push‑to‑talk (PTT) interoperability is governed by standards and profiles built on cellular and land mobile radio standards (notably 3GPP standards for LTE/5G Mission‑Critical Push‑to‑Talk — MCPTT — and evolving NTN work), plus industry bodies and public‑safety forums that define operational profiles. Key standard authors/owners include 3GPP (MCPTT, Mission Critical Services), TIA/ETSI/IEEE for radio interfaces, and public‑safety stakeholders (SAFECOM, NPSTC); vendors (e.g., Motorola, L3Harris, AT&T/Verizon public‑safety solutions) implement and certify to those standards.
First responders can recognize illegal jamming by sudden simultaneous loss/degradation of multiple radio/ cellular signals in a localized area, intermittent or repeating loss patterns, unusually high noise floor on receivers, or alerts from RF monitoring tools. Immediate steps: move to a safe area (if possible), switch to alternate frequency bands or prebriefed backup channels/networks (e.g., FirstNet, encrypted talkgroups), enable known resilient modes (satellite/mesh radios or hardened PTT apps), report the incident to communications/technical leads and spectrum authorities (FCC/CISA/DHS), and use RF‑directional detection equipment or S&T/CISA guidance teams when trained to locate emitters.
S&T tests and evaluates multiple counter‑jamming technologies including detection systems (RF spectrum monitoring and anomaly detection), direction‑finding/location (triangulation/DF antennas), selective signal filtering and resilient waveforms, and redundant/back‑up paths (satellite links, private networks, mesh radios, FirstNet). Testing covers jammer resilience, mitigation algorithms, and operator training to identify and respond to interference.
By engaging in 5G/6G standards work, S&T seeks to embed DHS resilience and interoperability requirements into early technical specifications (chipset, radio stack, core network, management APIs). Concretely this informs DHS Component procurement/specs (non‑proprietary, standards‑based requirements), guides vendor selection and test criteria (validated interoperability/resilience), supports pilot/demonstration buys, and yields operational guidance/configurations and test results Components can adopt for hardened 5G/6G deployments.