SIGFOX VERIFIED - OVH · ry x sigfox_verified ultra narrow band modem requirements specification...

SIGFOX

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SIGFOX_VERIFIED ULTRA NARROW BANDMODEM REQUIREMENTS SPECIFICATION FOR

RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0

DATE: 2017, APR 14TH

SIGFOX_VERIFIEDULTRA NARROW BAND MODEM REQUIREMENTS SPECIFICATION

FOR RC1-UDL

NOTICE: THE CONTENT OF THIS DOCUMENT IS THE SIGFOX PROPRIETARY AND SHALL NOT BEDISCLOSED, DISSEMINATED, COPIED, OR USED EXCEPT FOR PURPOSES EXPRESSLY AUTHORIZED IN

WRITING BY SIGFOX.

COPYRIGHT SIGFOX. ALL RIGHTS RESERVED PAGE 1 OF 21

SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


Revision HistoryRevision Number Date (MM/DD/YYYY) Change Description

0.1 2012 Sept 20th Draft revision

1.0 2012 Nov 16th Released for RF

1.1 2013 March 11th Remove Tx and Tx consumption and Rx consumption

1.2 2013 April 9th Add prerequisite for protocol.

1.3 2013 Sept 10th Add error baudrate requirement, Add requirements for class and carrier frequency

1.4 2013, October 11th Change Baudrate in RX mode and RX requirements

1.5 2013, October 31st Add requirement for test modes in RX and TX, Mention on the 2 RX modes sup-ported by SIGFOX network.

1.6 2013, Nov 7th Specify static absolute frequency carrier.

1.7 2014,Jan 28th Numbering of requirements, specify input power requirement for modulation.

1.8 2014, Feb 10th specify the downling modulation df and BT

1.9 2014,Feb 21th Remove spec unused, add test conditions for spectrum, Carrier frequency val-ues/bandwidth

2.0 2014,March 18 Add mode 2 and 3 for RX part. Add 100 bps RX 600bps RX and 1000bps RXBPSK

2.1 2014 June 18 Change 600bps uplink for FCC spectrum requirement and Downlink specificationsrf.

2.2 2014 July 15 Mention for FCC requirements.

2.3 2014, July 16 Add some protocol overview

2.4 2014, July 28 Add details on test bitstream description (ramp up and down)

2.5 2014, August 2 Modification for output power FCC class.

2.6 2014, September 29 Add table for ETSI/FCC frequency allocations.

2.7 2014, November 17th Correction value for carrier frequency stability requirement. 4 symbols duration inFCC mode. 4*1.66ms 3.2.6 Noise figure requirement not mandatory.

2.8 2014, Feb 19th Mention optional requirement concerning downlink selectivity, blocking .. Change600bps spectrum shaping

2.9 2015, April 1st Add requirements for oscillator accuracy

2.A 2015,April 10th Specify oscillator for static drift.

2.B 2015, May 18th Add ramp up and down specification for modulation.

2.C 2015, June 18th Define uplink/downlink frequencies for FCC US devices, Add note for maximumoutput radiated power definition.

2.D 2015, July 28th Update the FCC device class information

2.E 2015, Sept 29th Rework the document to be generated with latex

2.F 2016, May 23th Change test ID,key value for certification. RCZx radio conf SIGFOX new formatreplacing ETSI, FCC old modes

2.G 2016, Sep 28th Change the RCZ3j config for excursion 36KHz , and frequency accuracy from20ppm to 5ppm requirement (SPEC-113)

2.H 2016, Oct 20th Change the baudrate tolerance criteria (SPEC-117) and add RCZ3 36kHz to192kHz information.(SPEC-116)

2.I 2016, Nov 29th Update SIGFOX Logos (SPEC-127)

2.J 2017, 4th Add mandatory RX_GFSK test mode with RSSI value returned. Change all SIG-FOX Ready and P1 by SIGFOX Verified naming rules (SPEC-130)

2.K 2017, 30th Fix an issue in requirement numbering for RCZ3J (SPEC-132)

2.L 2017, 23rd Rename RCZ3j and RCZ3k into RCZ3a RCZ7 respectively (SPEC-133 134),change RF output level measurements (SPEC-135)

3.0 2017, Apr 14th Generation of specification based on activated features (SPEC-137) - rework afterreview


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


Contents

1 Introduction 41.1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.2 Requirements coding rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 Acronyms and abbreviations 5

3 SIGFOX Verified Candidate 63.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63.2 Pre-requisites for Tests execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63.3 Pre-requisite for Certificate delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4 Manufacturing / Production Requirements 84.1 Pre-requisites for production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

5 Operational Requirements 105.1 Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105.2 TX RF modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105.3 TX Baudrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115.4 Output Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.5 Carrier frequency stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.6 RX Demodulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.7 Rx Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.8 Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145.9 Timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155.10 Operational Frequency Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

6 Additional Measurements 176.1 Conducted TX Output power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176.2 Validation of the information contained in the OOB Frame . . . . . . . . . . . . . . . . . . . . 17

A Appendix: Guidelines to design an UNB_MODEM 18A.1 Implement the TX Modulation - DBPSK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18A.2 Implement the TX Baudrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20A.3 Implement the AES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20A.4 Implement the Non Volatile Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20A.5 Implement the SIGFOX Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21A.6 Implement the RX Demodulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


1 IntroductionThis document is intended to specify technical operational requirements for a SIGFOX Verified UNB_MODEM:

• RF requirements,• SIGFOX Protocol Requirements.

This document gives also some guidelines on the design of a SIGFOX UNB_MODEM and thus identify theoperational constraints and dependancies.

1.1 ScopeUNB_MODEM is a part of the SIGFOX system as briefly described by simplified diagram below.This document describes product requirements for SIGFOX_VERIFIED UNB_MODEM.Reader has to notice that the present document focuses on SIGFOX system.A commercial product might also integrate other systems, such as Bluetooth, Wifi, ... (multi-system device)All following requirements are mandatory to create a SIGFOX network compliant modem.

This document describes Uplink and Downlink aspects.SIGFOX network is bi-directional. Anyway, only the Uplink mode is mandatory. The Downlink mode is op-tional.


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


1.2 Requirements coding rulesIn order to enable requirement traceability, each requirement is referenced as following:

[<Document Code>-<product mnemonic>-<chrono number>]

[PRS-UNB_MODEM-xxx]requirement body

2 Acronyms and abbreviations- 2GFSK: 2-Level Gaussian Frequency Shift Keying

- AES: Advanced Encryption Standard

- Att: Attenuator

- CAB: Client Application Board

- CBC: Cipher Block Chaining

- CS: Carrier Sense

- DBPSK: Differential Binary Phase-Shift Keying

- DUT: Device Under Test

- LBT: Listen Before Talk

- NVM: Non Volatile memory

- PAC: Porting Authorization Code

- PER: Packet Error Rate

- PMR: Private Mobile Radio

- RF: Radio Frequency

- SMIQ: Vector Signal Generator

- SOC: System On Chip

- UNB_MODEM: Ultra Narrow Band MODEM

- UNBT: Ultra Narrow Band Transceiver


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


3 SIGFOX Verified Candidate

3.1 Overview

3.2 Pre-requisites for Tests execution[PRS-UNB_MODEM-10] Input Power Supply

Pre-Requisite Description: Manufacturer has to provide the nominal value and the range of input powersupply voltage that will be available for the final customer. (Operational Test will be executed on min, maxand nominal values)

[PRS-UNB_MODEM-11] Input Power Supply Testability

Pre-Requisite Description: Manufacturer has to provide a way to test the full range of power supplydelivered in previous pre-requisite.

[PRS-UNB_MODEM-12] Operational Temperature

Pre-Requisite Description: Manufacturer has to provide the range of temperature where the device isoperational.

[PRS-UNB_MODEM-13] Oscillator datasheet

Pre-Requisite Description: Manufacturer has to provide the datasheet of the radio oscillator.

[PRS-UNB_MODEM-14] RF connector


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


Pre-Requisite Description: UNB_MODEM must have an RF connector (SMA, ... ) to be able to performmeasurements in conducted mode.

[PRS-UNB_MODEM-15] Software version flashed

Pre-Requisite Description: UNB_MODEM must have the software version, candidate for the certificationflashed in it.

[PRS-UNB_MODEM-16] Software version check

Pre-Requisite Description: UNB_MODEM must provide a way to check the Software version numberflashed. SW version is applicable only for the SIGFOX Modulation and Protocol modem critical part.

[PRS-UNB_MODEM-17] Prototype closed to pre-production sample

Pre-Requisite Description: UNB_MODEM candidate must be as close as possible to the pre-productionsample.

[PRS-UNB_MODEM-18] Candidate Power Supply

Pre-Requisite Description: UNB_MODEM candidate must be powered by the same power supply as thefinal product.

[PRS-UNB_MODEM-19] Frequency Calibration

Pre-Requisite Description: UNB_MODEM candidate must be calibrated in Frequency +/- 500 Hz.

[PRS-UNB_MODEM-20] Modulated Continuous Wave CM test mode available

Pre-Requisite Description: Manufacturer has to provide a way to generate a modulated continuous wavesignal at 868.1300 MHz +/- 500 Hz .

[PRS-UNB_MODEM-21] RX RSSI Calibration DOWNLINK-MODEM

Pre-Requisite Description: UNB_MODEM candidate must be calibrated in RX RSSI level +/- 2 dBm .

[PRS-UNB_MODEM-22] RX GFSK Reporting DOWNLINK-MODEM

Pre-Requisite Description: UNB_MODEM candidate must provide a way to know that the frame isreceived.


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


[PRS-UNB_MODEM-23] User Manual

Pre-Requisite Description: The Device Maker must provide a User Manual with all the information to beable to execute the tests. The final certification will only apply to the commands used during SIGFOX TestExecution. Any other command, part of the User Manual will not be considered.

[PRS-UNB_MODEM-24] Test Modes availability

Pre-Requisite Description: UNB_MODEM must provide an interface to activate all SIGFOX Library testmodes. This can be done through AT commands, Built-in tests (hardcoded functions), GPIOs, ...

[PRS-UNB_MODEM-25] Specific ID and Key

Pre-Requisite Description: UNB_MODEM must be flashed with a specific test Key and test ID for thecertification.

• ID = 0xFEDCBA98 ( ID[3]=FE, ID[0]=98 )• KEY = 0123456789ABCDEF0123456789ABCDEF ( KEY[0]=01, KEY[15]=EF )

[PRS-UNB_MODEM-26] Public Key

Pre-Requisite Description: UNB_MODEM must be flashed with a second key called public key for au-thentication with ID and public key. The device must allow a way to switch from private to public key to becompatible with SIGFOX Network Emulator Kit (SNEK). This requirement is only applicable for Module,Reference Design and Development solutions.

• KEY = 00112233445566778899AABBCCDDEEFF ( KEY[0]=00, KEY[15]=FF )

3.3 Pre-requisite for Certificate delivery[PRS-UNB_MODEM-30] Documentation

Pre-Requisite Description: Manufacturer has to provide to SIGFOX the following documentation to beable to get its SIGFOX Verified Certificate :

• Build of Material ( BOM ) with version number• Schematics with version number• PCB Layout with version number• SIGFOX Modulation and Protocol firmware version number• Datasheet

4 Manufacturing / Production Requirements


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


4.1 Pre-requisites for production[PRS-UNB_MODEM-40] Frequency Offset Calibration parameter

Pre-Requisite Description: Manufacturer has to provide a way to set the Frequency offset of the devicefor Calibration purpose (This offset should be apply to Uplink and Downlink Frequency) .

[PRS-UNB_MODEM-41] RX RSSI Offset Calibration parameter DOWNLINK-MODEM

Pre-Requisite Description: Manufacturer has to provide a way to set the RX RSSI offset of the device forCalibration purpose.

[PRS-UNB_MODEM-42] RX GFSK test mode available DOWNLINK-MODEM

Pre-Requisite Description: Manufacturer has to provide a way to test the downlink feature on the modemthrough the RX_GFSK.

[PRS-UNB_MODEM-43] RX RSSI value available DOWNLINK-MODEM

Pre-Requisite Description: Manufacturer has to provide a way to get the RSSI level through theRX_GFSK.

[PRS-UNB_MODEM-44] TX BPSK test mode available

Pre-Requisite Description: Manufacturer has to provide a way to test the uplink modulated feature on themodem through the TX_BPSK SIGFOX library test mode.

[PRS-UNB_MODEM-45] Continuous Wave CW test mode available

Pre-Requisite Description: Manufacturer has to provide a way to generate a continuous wave unmodu-lated signal at a specific frequency +/- 500 Hz.

[PRS-UNB_MODEM-46] Access to ID and PAC

Pre-Requisite Description: UNB_MODEM must provide a way to get ID and initial PAC.

• ID = Unique ID (4 bytes length)• PAC = Initial PAC used for Device registering on SIGFOX network (8 bytes length) : mandatory to

give to customer for registering


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


5 Operational RequirementsThe following operational requirements have to be followed on all range of the input power supply. Testswill be executed on min and max value of the range.

5.1 Synthesizer[PRS-UNB_MODEM-50] Frequency Steps

Specification Description: UNB_MODEM unmodulated carrier frequency synthesis must have a maxi-mum ”minimum programmable step” of 500 Hz.

[PRS-UNB_MODEM-51] Carrier Frequency

Specification Description: UNB_MODEM must respect the operational central frequency +/- 500 Hz, ofSIGFOX network.See the following table:

SIGFOX zone Uplink (MHz) Downlink (MHz) Bandwidth (KHz)

RC1 868.1300 869.5250 192(+/- 96)

[PRS-UNB_MODEM-52] Static Frequency Tolerance

Specification Description: UNB_MODEM carrier frequency (absolute value) must be at +/- 20 ppm foroperational bands.These 20 ppm are managed by the SIGFOX system (network + Firmware library) .This requirement respects the ETS 300-220.One solution is to use a crystal or TCXO with these characteristics:

• Static Frequency Tolerance: precision is not so important if this parameter is calibrated at factory inorder to cancel this static imprecision.

• Temperature Frequency tolerance added to Ageing frequency tolerance must be less or equal to +/-20 ppm during all the product life.

All other system can be used if the global imprecision is +/- 20 ppm for operational bands all over theproduct life.

5.2 TX RF modulation[PRS-UNB_MODEM-60] DBPSK Modulation envelop

Specification Description: UNB_MODEM must use DBPSK modulation. Modulation mapping (0: modu-late 1: do not modulate)

[PRS-UNB_MODEM-61] Phase Measurement


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


Specification Description: UNB_MODEM DBPSK modulation must be compliant with following perfor-mances : Phase error : 180 degree Celsius +/- 10 % Max from one signal to another.

[PRS-UNB_MODEM-62] Extra symbols before the first SIGFOX bit of the frame

Specification Description: Transmission must include an extra symbol timing from 0 to 2 symbols timebefore the first SIGFOX bit. No phase shifting is allowed during this phase except at the symbol time.

• Extra symbols timing before the first SIGFOX bit of the frame

[PRS-UNB_MODEM-63] Extra symbols after the last SIGFOX bit of the frame

Specification Description: Transmission must include an extra symbol timing from 0 to 2 symbols timeafter the transmission of the last SIGFOX bit. No phase shifting is allowed during this phase except at thesymbol time.

• Extra symbols timing after the last SIGFOX bit of the frame

5.3 TX Baudrate[PRS-UNB_MODEM-70] TX Baudrate

Specification Description: UNB_MODEM must be able to transmit at a baudrate of 100 bps (standardSIGFOX rate for ETSI) with DBPSK modulation with following tolerances:

• Symbol duration : +/- 1 %• Cumulated error rate : 0.1 % of the whole ideal transmission time. (i.e : for a 26 bytes frame (2.08

s duration), tolerance of 2.08 ms )


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


5.4 Output Spectrum[PRS-UNB_MODEM-80] Spectrum and Spurious

Specification Description: UNB_MODEM must respect spectrum occupation for a 100 bps:

• -20dBc @ +/- 100Hz• -40dBc @ +/- 300Hz• -50dBc @ +/- 500Hz

Above these frequencies, must respect ETS 300-220.

Note on Spurious: SIGFOX will not certify your module for ETSI, but gives you advices and referenciesfor customer to ensure transceivers will satisfy also ETSI.UNB_MODEM must be compliant with ETS 300-220.

5.5 Carrier frequency stability[PRS-UNB_MODEM-90] Frequency Dynamic Drift


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


Specification Description: UNB_MODEM carrier frequency, during transmission from bit sync to end offrame, must respect a max frequency shifting about :

• Drift average of 20 Hz/s from end of synchro bits to the end of a transmission of the maximumSIGFOX frame. Method the least squares will be used for the measurement.

• Drift peak of 30 Hz/s from the first quarter of the synchro bits to the end of the synchro bits

See the following Frequency Drift graph:

5.6 RX Demodulation[PRS-UNB_MODEM-100] 2GFSK 600bps DOWNLINK-MODEM

Specification Description: UNB_MODEM must be able to demodulate 2GFSK at 600bps (BT = 1.0,delta_f = +/- 800Hz).

5.7 Rx Sensitivity[PRS-UNB_MODEM-110] RX Sensitivity 2GFSK 600bps DOWNLINK-MODEM

Specification Description: UNB_MODEM sensitivity for a single link for standard mode (600bps 2GFSK): Sensitivity should be <= -125 dBm with a PER at 10 % on 100 frames sent.

[PRS-UNB_MODEM-111] SIGFOX RX Sensitivity DOWNLINK-MODEM

Specification Description: UNB_MODEM sensitivity for a single link for standard mode (600bps 2GFSK): Sensitivity should be <= -126 dBm with a PER at 10 % on 1000 frames sent.


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


5.8 Protocol[PRS-UNB_MODEM-120] AES

Specification Description: UNB_MODEM must include an AES module with CBC mode with a 16 byteskey (Hardware or Software) for authentication on network. The Init Vector (IV) is set to 0.

[PRS-UNB_MODEM-121] NVM Frequency Storage

Specification Description: UNB_MODEM must include a non volatile memory for frequency carrier stor-age (at least 2 bytes).

[PRS-UNB_MODEM-122] NVM Sequence Number Storage

Specification Description: UNB_MODEM must include a non volatile memory for a protocol sequencenumber storage (at least 2 bytes), not readable by application.

[PRS-UNB_MODEM-123] NVM ID

Specification Description: UNB_MODEM must include a Non Volatile Read Only Memory to store ID(32bits).ID must be Read Only.

[PRS-UNB_MODEM-124] NVM KEY

Specification Description: UNB_MODEM must include a Non Volatile Read Only Memory to storeKey(128bits). KEY must be Read Only by AES Module.

[PRS-UNB_MODEM-125] Number of frames per message in Uplink mode

Specification Description: In normal operational mode, the UNB_MODEM must send 3 SIGFOX RFframes per customer message.

[PRS-UNB_MODEM-126] Uplink

Specification Description: The device has to be able to send SIGFOX Frame through the SIGFOX LibraryTest Mode function.

[PRS-UNB_MODEM-127] Downlink DOWNLINK-MODEM

Specification Description: The device has to be able to receive SIGFOX Frames using the RX_GFSK .

[PRS-UNB_MODEM-128] Downlink-rssi DOWNLINK-MODEM

Specification Description: The device must return the RSSI level when receiving a GFSK frame inRX_GFSK .


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


[PRS-UNB_MODEM-129] Number of repeated Uplink frame in bi-directional modeDOWNLINK-MODEM

Specification Description: UNB_MODEM must send 3 SIGFOX RF frames maximum per customer mes-sage for a message requesting a downlink response.The repetition may be configured by the manufacturer through the tx_repeat parameter.

5.9 Timings[PRS-UNB_MODEM-130] TX Interframe Timing in Uplink mode

Specification Description: In normal operational mode, the TX interframe duration in Uplink mode has tobe between 0 ms and 2000 ms .

[PRS-UNB_MODEM-131] TX Interframe Timing in Bi-directional mode DOWNLINK-MODEM

Specification Description: In normal operational mode, the TX interframe duration in Uplink/Downlinkmode has to be between 500 ms and 525 ms, in case of frame repetition (tx_repeat parameter greatherthan 0). .

[PRS-UNB_MODEM-132] RX Listening Window duration DOWNLINK-MODEM

Specification Description: The UNB_MODEM must be able to receive the Downlink frame sent in a RXListening window of 25 s, following the implementation described in the graph:

Figure 1: Downlink Timings

[PRS-UNB_MODEM-133] RX Wait time before Rx Listening Window DOWNLINK-MODEM

Specification Description: After sending the first Uplink frame, the device has to wait for 20 s beforeentering the RX Listening window, following the implementation described in the figure 1.


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


[PRS-UNB_MODEM-134] RX to OOB(ack) Timing DOWNLINK-MODEM

Specification Description: After receiving the downlink frame, the device has to wait 1.4 s and no laterthan 4 s before sending the acknowlegement frame (OOB), following the implementation described in thefigure 1.

5.10 Operational Frequency Range[PRS-UNB_MODEM-140] Operational Frequency Range

Specification Description: Range of frequencies used during transmission to be less than 192 kHzaround the Central frequency. The distribution has to be uniform.


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


6 Additional Measurements

6.1 Conducted TX Output power[PRS-UNB_MODEM-150] Conducted Output Power

Measurement: To be able to benefit from optimal Quality of Service with a balanced budget link ,SIGFOXrecommends to respect the following maximum output radiated power : 14dBm ERP( or 16dBm EIRP).Device or module can output more than 14dBm in conducted mode due to some antenna loss in thecomplete end product.

6.2 Validation of the information contained in the OOB Frame[PRS-UNB_MODEM-160] RSSI level DOWNLINK-MODEM

Measurement: At a specific Downlink Frame level, the OOB shall return the same level of RSSI of thereceived GFSK ( tolerance ) or 0 is the device is not able to return it.

[PRS-UNB_MODEM-161] DUT Temperature level

Measurement: The OOB shall return the level of Temperature at which the test is executed or 0 is thedevice is not able to return it.

[PRS-UNB_MODEM-162] DUT Voltage level

Measurement: The OOB shall return the level of Voltage at which the test is executed or 0 is the deviceis not able to return it.


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


A Appendix: Guidelines to design an UNB_MODEMThis chapter will only guide you on the choice of the RF chipset and micro-crontroller, and are not in anyway mandatory for the implementation of a SIGFOX_READY UNB_MODEM. The mandatory require-ments that need to be filled in by the UNB_MODEM are described in section "Operational Requirements".

A.1 Implement the TX Modulation - DBPSKThis modulation can be built by hardware (not available in all RF chipsets) or by software.Even if the RF chipset supports the DBPSK modulation, manufacturers have to takecare of the SIGFOXrequirements regarding the spectral occupation.

Here are the main parameters of the DBPSK modulation used by the SIGFOX protocol:

• Binary (Pi) Phase-Shift Keying with following mapping: 0: change phase, 1:keep phase.• Amplitude modulation ( ramp-down and ramp-up of the signal amplitude at each phase change ). It

reduces the spectral occupation.

To be able to build this modulation in software, the PA and the Frequency Steps of the RF chipset have tobe controlled by the host micro-controller.There could be 2 ways to implement the DBPSK modulation:

• Using Continuous Wave• Using 4GFSK Modulation

DBPSK Using Continuous Wave

Continuous wave mode (also known as CE/FCC certification test mode) is often available in the RF Chipset.This mode offers the ability to modify dynamically the carrier frequency and the PA power.

PrincipleThe Pi phase shifting is obtained by accumalating several frequency steps during a certain amount of time.The spectral spread is limited by decreasing the PA power during the carrier frequency change.Therefore, the host micro-controller has to be able to control the PA and Frequency Steps, and both in away that allow to execute these commands in less time than a symbol.

Chip requirementsAs a consequence, here are the following guidelines:

PA Steps

Recommendation: As PA ramping up and down (AM) is a way to ensure SIGFOX spectrum requirementacceptance, RF Chipset shall have a minimum number of steps available.Profiles available are composed of at least more than 32 PA steps.RF Chipset PA must control an output power range from the maximum output power required in the spec-ification to minimum of -70dBm to have the best results.

Frequency Steps


SIGFOX

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RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


Recommendation: If your RF chipset has no direct phase control, you must ensure to have the access tosteps resolution of at least 100Hz.If phase is directly tunable by user, you must ensure there is filter on this command to ensure filteredphase shift.

Many RF chipsets do not allow to control the frequency out of a well known state of the internalyRF Chipset state machine, make sure that this is possible to control it without restriction.

CPU load/ressources

Recommendation: The software modulation needs a real time control of the RF Chipset during the mod-ulation procedure. To have it working you need:

• A symbol rate preemptive (and not nested) timer interruption with a callback for the Transmit function.• A sufficient flash storage for the PA / Frequency modulation tables.• Regular timing in commands of the PA and Frequency programmation of the RF Chipset. ( Curently

observed timing is around 12 us for ETSI)

DBPSK Using 4GFSK Modulation

PrincipleThe DBPSK may be built from a 4GFSK, using 3 patterns.Example of such an implementation followed:

• 11 : Used for Positive Frequency Excursion• 00 : Used for Center Frequency• 10 : Used for Negative Frequency Excursion• 01 : Unused

The Frequency excursion is programmed into the RF Chip to ensure Pi radian phase.Negative and Positive excursions alternatively are used to ensure a symetric spectrum.

Here is the data to push into a 4GFSK @ 500 bps to modulate a DBPSK @ 100bps, for an examplebitstream ’0101’ to be send on the air.

’0’ ’1100000000’ Use the 11 symbol to execute phase shifting (Pi) and follow this symbol withCenter frequency symbol 00

’1’ ’0000000000’ Use the 00 to ensure there is no change in phase when transmitting a ’1’

’0’ ’1000000000’ Use the 01 symbol ( as 11 was used previously ) to execute phase shifting (Pi)and follow this symbol with Center frequency symbol 00

’1’ ’0000000000’ Use the 00 to ensure there is no change in phase when transmitting a ’1’

Once the phase shifting is in place with the 4GFSK, the amplitude has to be handled by synchronizingthe ramp-down, ramp-up of the PA with the phase change.

Chip requirementsAs a consequence, here are the following guidelines:


SIGFOX

PROPRIETA

RY


RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


Synchonization PA and Frequency

Recommendation: Synchronization between the PA ramp-down, ramp-up and the phase shifting isimportant for the spectral occupation.This may be done with an interrupt when FIFO is emptying. Real time is critical for the success of themodulation, as well as the spectral occupation: PA has to be at the minimum when the frequency is at itsmaximum.

Frequency Steps

Recommendation: The frequency execursion value must be programmable so that we can use it to havethe accurate Pi phase shifting.Many RF Chipset do not allow to set a custom value for this excursion: the feature has to be available inthe chip to build the DBPSK modulation.

A.2 Implement the TX BaudrateClock and Bitrate

Recommendation: As modulation bitrate is software dependent, you must ensure the clock used to se-quence the symbol will have enough precision to achieve the TX Baurate specification.Bitrate precision has a direct impact on the Base Station demodulation.

A.3 Implement the AESAES Hardware or software

Recommendation: Your micro-controller (or RF Chipset) must include an AES module (Hardware orSoftware) for authentication on network.If hardware AES module does not exist in hardware, AES software is possible but takes 5KB (or 1.8KB)more.

A.4 Implement the Non Volatile MemoryNVM - Non volatile memory such as EEPROM


SIGFOX

PROPRIETA

RY


RC1-UDL

REF: PRS-UNB_MODEM

REVISION: 3.0


Recommendation: Micro-controller must include a Non Volatile Memory for protocol library informationstorage.The SIGFOX library needs to store 4 bytes in that NVM at each frame sent on the air.

A.5 Implement the SIGFOX ProtocolTo faster manufacturers development of SIGFOX UNB_MODEM, SIGFOX provides a Software protocol li-brary.This library is compiled by SIGFOX on the targetted microprocessor ( with all necessary compilation options) and delivered to the partner as a binary.Manufacturer’s role is then to implement the Upper Level appplication and the Low Level drivers accord-ing to the RF chipset.

ROM or Flash

Recommendation: Micro-controller must have a minimum of Read-Only Memory for SIGFOX binary Li-brary and RF Firmware storage. About 7KBytes in library.Additional information, such as identifier ( Read Only ) and key ( Read Only by the AES Module ) will needto be stored too.

RAM

Recommendation: Micro-controller must include some RAM or SRAM to run the whole firmware ( appli-cation, SIGFOX protocol library and Low Level drivers ).RAM used by the library: 100 bytes.

A.6 Implement the RX DemodulationRX Demodulation DOWNLINK-MODEM

Recommendation: SIGFOX network does not need any reception part on devices to be operated. If man-ufacturer wants to have the opportunity to implement the reception part for bi-directional applications, ithas to ensure the UNB_MODEM is able to support demodulation described into the "Operational require-ments".


SIGFOX VERIFIED - OVH · ry x sigfox_verified ultra narrow band modem requirements specification...

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