Cellular Product Regulatory Pathway Whitepaper

PREFACE

Building a new cellular-based product requires various technical and regulatory considerations. We will examine possible product cellular certification paths, requirements, and suggestions useful for project planning; specifically, we will examine the subject in the following order:

• Introduction
• General Regulations
• Relevant LTE Bands
• Carrier Comparisons
• Specific Carries’ Certification Flow
• Regulatory Cost Analysis
• References

INTRODUCTION

To develop a successful cellular product to market, three pillars must be simultaneously considered during project planning and execution – development, regulatory, and manufacturing. This whitepaper will address the regulatory portion.

Common questions regulatory certification groups will ask:

1. What chipset/module is the device based on? What is the FCC ID and (if applicable) PTCRB certification?
2. Will the device be used fewer than 20 cm from a person?
   1. If yes, specific Absorption Rate (SAR) Tests are required. Otherwise not.
3. Does the device have an internal or external antenna?
   1. If the cabling to antenna less than 20 cm?
      1. If yes, carrier OTA tests are required.
4. How many SIM cards are present? Are they removable or soldered?
5. What technology (i.e. LTE CAT M1) is used? What bands are enabled?
   1. A module can be programmed to only enable certain bands of interest, helping limit regulatory testing by targeting the optimal market.
6. Does the device use special command software, such as AT commands for settings or configuration?

GENERAL REGULATIONS

• FCC (All Carriers)
  • If using a pre-approved module, submission for an FCC cert or ID is not required. Instead, the FCC requires the manufacturer to put a label specifying which pre-certified module is in the device.
  • Unintentional emission tests are still required and can be performed by a third-party lab. No submission of the test results to the FCC is required. This is referred to the Suppliers Declaration of Conformity (SDoC) [1].

• PTCRB (AT&T and T-Mobile, not Verizon carriers)
  • With a pre-certified module, there are the following tests:
    • OTA (TRP, TIS)
    • RSE
    • U-SIM
  • Additional requirements require OTA and cybersecurity considerations
  • Manufacturer submitted for a PTCRB cert will still need to register device on the PTCRB website, even if using a pre-approved chipset
• Carrier specific testing (subsequently described)

Important consideration:

Not all carriers mandate PTCRB. For example, Verizon does not need PTCRB and runs its own certification process known as the open development initiatives (ODI). This process can be custom and based on the number of simultaneous radios (referred to as coexistence); the cost can be substantial for complex designs. However, if the end goal is to ensure carrier operation on AT&T or T-Mobile, PTCRB would be required.

Additionally, every three years, a PTCRB recertification is required; however, an abbreviated effort is allowed (typically one-third the original cost) if the design is unmodified. If the design is modified, such as due to an antenna change, then an engineering change order (ECO) is required, and the cost is still typically a fraction of the original certification cost.

RELEVANT LTE BANDS

Band	Uplink (Lo)		Uplink (Hi)	Downlink (Lo)		Downlink (Hi)
2	1850 MHz	–	1910 MHz	1930 MHz	–	1990 MHz
4	1710 MHz	–	1755 MHz	2110 MHz	–	2155 MHz
5	824 MHz	–	849 MHz	869 MHz	–	894 MHz
12	699 MHz	–	716 MHz	729 MHz	–	746 MHz
13	777 MHz	–	787 MHz	746 MHz	–	756 MHz
14	788 MHz	–	798 MHz	758 MHz	–	768 MHz
17	704 MHz	–	716 MHz	734 MHz	–	746 MHz
25	1850 MHz	–	1915 MHz	1930 MHz	–	1995 MHz
26	814 MHz	–	849 MHz	859 MHz	–	894 MHz
29	N/A			717 MHz	–	728 MHz
30	2305 MHz	–	2315 MHz	2350 MHz	–	2360 MHz
41	2496 MHz		2690 MHz	2496 MHz		2690 MHz
48	3550 MHz	–	3700 MHz	3550 MHz	–	3700 MHz
66	1710 MHz	–	1780 MHz	2110 MHz	–	2200 MHz
71	663 MHz	–	698 MHz	617 MHz	–	652 MHz

CARRIER COMPARISON

A device operating on a specific carrier does not necessarily need all the possible bands, since the exact chosen bands depend on the operating location.

	AT&T	T-Mobile	Sprint	Verizon
PTCRB required	Yes	Yes	No	No
Possible 4G LTE Bands	2, 4, 5, 12, 14, 17, 29, 30, 66	2, 4, 12, 48, 66, 71	25, 26, 41	2, 4, 5, 13, 66

SPECIFIC CARRIERS’ CERTIFICATION FLOW

AT&T:

Trendi testing is the Testing Requirements for Network Ready Devices for IoT, an AT&T process. This is a 24-hour test in which the carrier sends test SMS messages to the device. The user is expected to interact with the cellular device to allow the carrier to baseline device performance and data usage.

Expected Behavior:

• Ensure devices is not aggressive when unable to reach network.
• Route device reset is permitted. However, steady state behavior must not exceed once every four hours.
• Number of authentication requests must be fewer than 19 per hour. Ideal target is fewer than 6.
  

Verizon:

T-Mobile:

REGULATORY COST ANALYSIS

The following variables impact the certification cost:

• Technology (CAT M1 vs CAT M1 + NBIoT)
• Specific Bands
• Supported Carries
• Multiple Radios
• Fallback Mechanism (if LTE not available)
• Antenna Cable Length

Carriers and specific bands impact the certification costs. Also, integrating multiple radios (Bluetooth, Wi-Fi, Cellular, etc.) require coexistence to limit radio cross talk and would increase cert cost. Note that the exact chipset that is chosen does not significantly impact the regulatory cost, if it is already pre-certified and used as an integrated device.

Pre-certification could be used during development to mitigate the final certification effort.

In general, the rough cost (on the low end) for the simplest cellular regulatory certification is in the low five-figures, taking into consideration FCC, PTCRB testing + registration, and a carrier cert. However, the exact cost varies significantly based on the exact bands and carriers that are used.

REFERENCES

[1] – FCC Supplier’s Declaration of Conformity Guide https://apps.fcc.gov/kdb/GetAttachment.html?id=cPjFB7kIR2TMlwiHUNAbvA%3D%3D&desc=896810%20D01%20SDoC%20v02.pdf

[2] – 3GPP TS 36.101 V17.1.0 (2021-03) Standard. [https://www.etsi.org/deliver/etsi_ts/136100_136199/136101/10.17.00_60/ts_136101v101700p.pdf]