WIRELESS
COMMUNICATION
DEVICES
Full-stack wireless communication and PTT electronics engineering — P25 Phase 1 and Phase 2 CAI compliant radio electronics, TETRA V+D protocol stack, DMR Tier II and III, MCPTT 3GPP Release 13/14, custom RF transceiver design, AMBE+2 codec integration, AES-256 with OTAR encryption, high-noise audio system engineering, ATEX Zone 1 intrinsically safe radio electronics, and FCC Part 90 and ETSI EN 300 113 type approval.
The Engineering Problem
Custom Wireless Communication Development Is the Most Standards-Complex Domain in Commercial Electronics
P25 CAI, ETSI TETRA EN 300 392, and ETSI DMR TS 102 361 are multi-thousand-page specifications. A radio that transmits on P25 frequencies but whose CAI implementation does not correctly handle the IMBE frame format, FNE handshake, or DFSI timing passes superficial testing but fails at the protocol exchange the operational use case requires.
OTAR failure modes — out-of-coverage during broadcast, power-cycle during transfer, partial receipt — produce communications silence in the encrypted group at the worst possible moment. RF type approval compounds this: a transmitter designed for maximum output then filtered for spurious emissions loses output power through filter insertion loss, forcing either a higher-power PA or a coverage compromise — non-compliance discovered at the type approval lab, not at schematic review.
Three converging drivers are expanding the market: FirstNet/ESN moving public safety from narrowband LMR to broadband LTE/5G with MCPTT-to-P25/TETRA interworking requirements; Phase 1 FDMA-to-Phase 2 TDMA network upgrades demanding H-DQPSK radio electronics for specific sub-band allocations; and oil, gas, utilities, and mining operators requiring ATEX-certified, AES-256 encrypted, GPS-equipped radios for hazardous area and lone worker applications that commercial enterprise radio cannot satisfy.
Public Safety P25 & TETRA Radio Electronics
Enterprise DMR & PoC Communication Devices
MCPTT & 3GPP Broadband Communications
ATEX & Industrial Communications Electronics
Marine VHF & GMDSS Communications
Satellite PTT & Hybrid Coverage Electronics
Ruggedised Audio Accessories & Speaker-Microphones
Underground & Mine Communications
RF Transceiver Design & Link Budget
Custom RF transceiver PCB design for VHF (136-174MHz), UHF (380-520MHz), 700/800MHz, and 900MHz LMR band operation. Fractional-N PLL frequency synthesiser achieving sub-1ppm stability across -30°C to +60°C. Class C and E PA design for 1-25W with above 65% efficiency. PA harmonic filter co-designed with FCC Part 90 and ETSI EN 300 113 spurious emission limits from the first schematic. LNA and SAW bandpass front-end achieving sub-0.5µV sensitivity with -70dBm adjacent channel selectivity. Link budget analysis for deployment site coverage prediction.
P25 & TETRA Protocol Stack
P25 CAI Layer 1 CQPSK Phase 1 and H-DQPSK Phase 2 modulation compliant with TIA-102.BABA physical layer specification. P25 Layer 2 MAC and Layer 3 network protocol for conventional and trunked mode operation with TSBK channel access. TETRA V+D π/4 DQPSK physical layer with TDMA slot management and ACELP voice codec. TETRA DMO peer-to-peer operation. TETRA SIM authentication interface. DFSI, CSSI, and ISSI electronics for network integration. P25 CAP compliance assessment.
DMR & Enterprise Radio Electronics
DMR Tier II ETSI TS 102 361-1 compliant two-slot TDMA on 12.5kHz channel. DMR Tier III CSBK trunking protocol electronics for channel grant and denial management. AMBE+2 vocoder chip interface. NXDN FDMA 6.25kHz channel electronics for Kenwood/Icom IDAS systems. dPMR European enterprise radio. CTCSS and DCS tone generation and detection for analogue coexistence. PoC SIP/RTP with sub-500ms call setup. Enterprise PoC platform API integration — Motorola WAVE PTX, Zetron ACOM.
MCPTT & Broadband PTT
3GPP Release 13/14/15 MCPTT application layer protocol stack over LTE and 5G NR. MCPTT Floor Control Protocol for half-duplex group PTT. MCX services — MCPTT, MCVideo, MCData. FirstNet Band 14 (758-768/788-798MHz) and ESN compatible radio module interface. LTE Direct ProSe for direct mode without network coverage. MCPTT-to-LMR interworking gateway for P25 and TETRA bridge. PoC SIP/RTP with sub-500ms call setup.
Encryption & Communications Security
AES-256 hardware encryption engine for P25 E2EE in full and limited IV modes. OTAR electronics implementing P25 KMF protocol with explicit handling of seven documented failure scenarios — out-of-coverage during broadcast, power cycle during transfer, partial receipt. TETRA TEA2 and TEA3 Air Interface Encryption hardware. FIPS 140-2 Level 2 HSM awareness. KFD RS-232/USB interface for key loading. SRTP for MCPTT encrypted voice. PKI certificate management for LTE/5G MCPTT authentication.
Audio System Design for Mission-Critical
Electret and MEMS microphone signal conditioning for 100dB+ ambient noise rejection in first responder and industrial environments. Active noise cancellation feedforward and feedback electronics for speaker-microphone accessories. 1-3W audio amplifier for high-SPL outdoor output. AGC and audio companding for intelligibility across dynamic voice level range. PTT button hardware debounce achieving sub-5ms latency from button press to transmission. Acoustic seal design and transducer selection for earpiece isolation. VOX electronics with configurable threshold.
Type Approval & Regulatory Certification
FCC Part 90 type acceptance — conducted power, spurious emissions below -36dBm VHF, adjacent channel power ratio, modulation accuracy, frequency error measurement. ETSI EN 300 113 European analogue and digital narrow-band PMR type approval. FCC Part 80 marine VHF. IC RSS-119 Canadian LMR. CE RED for European market. P25 CAP for US public safety network compatibility. TETRA MoU type approval and interoperability testing. DMR Association Type Approval process management.
Environmental Qualification & ATEX
MIL-STD-810H Method 512.6 immersion; Method 516.8 shock; Method 514.8 vibration; Method 509.7 salt fog. IP67 and IP68 enclosure and connector sealing design. IECEx Ex ia Zone 1 intrinsically safe electronics with full entity parameter calculation for Group IIA/IIB/IIC gas classifications — Group IIC hydrogen minimum ignition energy 17µJ. ATEX Zone 1 Ex ia and Zone 2 Ex ec certification. IECEx coal mine intrinsically safe for underground mining. Man-down inactivity detection. GPS GNSS integration for CAD dispatch.
Chipsets & Platforms
Tested silicon and proven stacks — no experimental platform dependencies.
P25 CAI, TETRA V+D & Public Safety Communications Electronics
P25 Phase 2 TDMA: The Air Interface Engineering That Doubles System Capacity
A P25 radio on a public safety network must correctly implement CAI for trunked talkgroup calls, emergency pre-emption, AES-256 OTAR key management, GPS dispatch reporting, and ISSI inter-agency roaming — failing any one isolates the operator from their talkgroup when it matters most. Phase 2 doubles voice capacity by allocating two calls per 12.5kHz channel via two-slot TDMA, but H-DQPSK modulation requires a different signal processing chain from Phase 1 CQPSK with tighter frequency error requirements. Phase 1/Phase 2 hybrid coexistence requires the radio to determine network operational phase and switch accordingly — all implemented from the TIA-102.BABA specification, not from a compatibility claim.
DMR Tier III, ATEX Zone 1 & Industrial Communications Electronics
ATEX Zone 1 Ex ia: The Intrinsic Safety Engineering Challenge of an RF Transmitter
Enterprise and industrial PTT spans the widest requirements range of any wireless domain: low-cost PoC for logistics, IECEx Zone 1 AES-256 encrypted GPS radios with man-down for offshore platforms, DMR Tier III trunked systems with dispatcher console for transport control rooms. The technology selection is a fundamental architecture decision, not a feature comparison. IEC 60079-11 intrinsically safe electronics must limit released energy below the target gas group minimum ignition energy — Group IIA 180µJ, Group IIB 60µJ, Group IIC hydrogen 17µJ. A 1W RF PA dissipates 4–5W in the switching transistor, far exceeding every gas group budget, requiring hard separation between the PA and intrinsically safe circuits. Ankh designs ATEX radio electronics from the IS physics of the specific gas group, with entity parameters verified by a BASEEFA-approved certification body.
Marine VHF GMDSS, Satellite PTT & Specialist Audio Electronics
ITU-R M.493 DSC Format: The Standard Marine Electronics Engineers Evaluate Vendors On
Marine VHF DSC operates under the ITU Radio Regulations and IMO SOLAS framework — channel allocations, ITU-R M.493 DSC format, distress alert protocols, and GMDSS type approval entirely distinct from FCC Part 90 and ETSI EN 300 113. Class A DSC must correctly format and parse all message categories (distress, urgency, safety, routine, geographic area, group) to achieve GMDSS compatibility under SOLAS. Satellite PTT faces a different challenge: geostationary 250–600ms round-trip latency fundamentally changes the half-duplex user experience, requiring PTT floor control adaptation and visual floor status feedback. Ankh designs from the ITU-R M.493 recommendation and IEC 60945 marine standard — not from compatibility claims.
P25 and TETRA Compliance From the Protocol Specification, Not the Compatibility Claim
Transmitting on P25 frequencies is not P25 CAI compliance. CAI requires implementing CQPSK deviation and symbol rate, Layer 2 MAC frame formats, TSBK trunked channel access, DFSI base station timing, and FNE authentication — all defined across thousands of pages in the TIA-102 series. Ankh implements P25 CAI from the TIA-102 specification and validates against P25 CAP test procedures, not from reverse-engineering network traffic.
RF Type Approval Designed From the First PCB Layout
Filtering a maximum-power transmitter for spurious emission compliance introduces insertion loss that reduces conducted output below specification — requiring either a higher-power PA or a coverage compromise. Ankh designs the PA, harmonic filter, and antenna interface together from the first schematic, with FCC Part 90 and ETSI EN 300 113 emission limits as design constraints. The type approval test reveals compliance margin, not compliance failure.
Audio System Characterised for the Deployment Noise Environment
A -42dBV/Pa microphone calibrated in a 40dB test chamber produces noise-dominated, unintelligible transmitted audio when worn by a firefighter at 100dB ambient. Designing for first responder and industrial environments requires specifying microphone polar pattern, ANC algorithm tuning, and AGC at the deployment noise level — not the chamber measurement. Ankh characterises the audio system against the specific ambient noise of the target deployment environment.
OTAR Key Management Implemented for Operational Failure Mode
OTAR works when every radio is on-network and receives the broadcast cleanly. The failure mode — out-of-coverage during key changeover, partial receipt due to bit errors, power cycle during transfer — leaves the radio holding an invalid key set, producing communications silence in the encrypted talkgroup. Ankh designs OTAR with explicit handling of every failure scenario in the P25 KMF specification: the failure mode is a radio that retries on re-entry to coverage, not one that silently fails to decrypt.
P25 Phase 2 Trunked Portable Radio for a Public Safety Technology Company
P25 Phase 2 trunked portable radio for state and city public safety networks requiring TIA-102.BABA CAI compliance, dual Phase 1/Phase 2 operation, AES-256 OTAR with complete UKEK failure-mode handling, FCC Part 90 type acceptance across 700MHz and 800MHz, and P25 CAP validation against four incumbent system controller platforms.
Dual-mode CQPSK Phase 1 and H-DQPSK Phase 2 TDMA portable radio with modulation accuracy within ±1% of TIA-102.BABA deviation standard; TSBK channel grant and TDMA slot assignment; IMBE/AMBE+2 codec with SINAD above 12dB at -100dBm; AES-256 OTAR with explicit handling of seven failure scenarios; P25 CSSI dispatcher interface; 4-second GPS location reporting; MIL-STD-810H Methods 514.8/516.8/512.6/509.7; FCC Part 90 spurious below -36dBm; man-down detection with emergency auto-activation.
- FCC Part 90 type acceptance at first test submission across 700MHz and 800MHz sub-bands — spurious emissions below -36dBm at type approval laboratory
- P25 CAP validation achieved across four incumbent P25 system controller platforms — TSBK channel grant and TDMA slot assignment handling validated against each
- AES-256 OTAR UKEK protocol implemented with explicit handling of seven documented failure scenarios including power cycle during key transfer and out-of-coverage during OTAR broadcast
- MIL-STD-810H Methods 514.8/516.8/512.6/509.7 qualification achieved at first test submission — man-down detection and emergency auto-activation validated in qualification test programme
IECEx Zone 1 ATEX DMR Portable Radio for an Industrial Communications Technology Company
IECEx Zone 1 Ex ia certified DMR portable radio for North Sea offshore platforms and UK onshore refineries, requiring Group IIB entity parameter calculation, ETSI EN 300 113 European type approval, and a custom audio solution validated for 90dB pump house environments.
IECEx Zone 1 Ex ia DMR Tier II portable radio with full entity parameter calculation achieving Voc 4.5V and Isc 100mA with 100% margin to Group IIB IS standards; ETSI TS 102 361-1 CAI compliant DMR/analogue FM dual-mode; AES-256 E2EE; GPS with man-down and emergency priority call; custom noise-cancelling speaker-microphone achieving -12dB rejection at 90dB background; IP68 enclosure; MIL-STD-810H Method 516.8 1.5m drop; ATEX and IECEx certification by BASEEFA.
- IECEx and ATEX Zone 1 Ex ia certification issued by BASEEFA notified body — zero queries raised on entity parameter calculation at certification submission
- 340 radios deployed across 6 North Sea offshore platforms and 2 UK onshore refineries — zero ATEX safety incidents in 36 months of operational deployment
- Custom noise-cancelling speaker-microphone achieving -12dB noise rejection at 90dB background noise — designed and validated for refinery pump house acoustic environment
- FCC Part 90 UHF and ETSI EN 300 113 dual type approval — single hardware platform certified for North American and European market deployment
Building custom wireless communication or PTT electronics? Let's make every transmission count.
P25 and TETRA compliance from the TIA-102 and ETSI specifications, not from compatibility claims. RF type approval engineered from the first PCB layout, not discovered at the compliance test laboratory. Full-stack delivery from RF transceiver design through protocol stack through encryption through audio system through FCC Part 90 and ETSI type approval.
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