4.1. SCAP LTP overview

4.1.1. Overview

  • End-to-end security, from device to application, independent of operators or technologies

    • AES-256 GCM encryption

    • AES-256 GCM authentication with 96-bit tag

    • Anti-replay

    • LoRaWAN automatic join renewal

  • Improved QoS

    • Automatic switching between operators without roaming (Sigfox and LoRaWAN)

    • Automatic switching between private/public infrastructures (LoRaWAN)

    • MTU setting by route (Sigfox and LoRaWAN)

    • Automatic re-join after a number of attempts (LoRaWAN)

    • Management of retries by route (LoRaWAN)

    • Best radio parameter settings (no payload limitation)

  • Improved performance and simplified development (time-to-market reduction)

    • Payload size increase thanks to an on-the-fly segmentation and recombination process (2 patents pending)

    • Optimized data structure: RAW and BIN streams

    • Downlink padding management (Sigfox)

    • Device side generic interface (API and AT commands) -- Precompiled binaries available for several modems : Multitech, Murata, Nemeus, Telecom Design,

    • Server side generic interface REST APIs, operator agnostic (Sigfox, Orange, Loriot, TTN, Actility, )

    • Block size independent encrypted payload size

  • Integration

    • Device side (~30K bytes library)

      • Ready to flash binaries (Multitech, Murata, Nemeus, Telecom Design, )

      • SDK

      • Custom binary for SOC, micro-controllers or device

      • PLD reference design

    • Server side

      • SaaS platform

      • On premises

4.1.2. Description

The LPWAN networks allow wireless sensors to communicate with cloud-hosted or on-premises applications. These networks are characterized by a low throughput which enables very-long distance communication (up to 40km), and so a frugal base station territorial coverage. The sensors are generally ULP and may last for 10 years [^1]. These two key points make the LPWA networks very low cost and well suited for widely spread applications.

The thrifty nature of LPWA networks means they lack some features required for quick and robust application development. hl2gener provides theses features on top of the LPWA networks by implementing the SCAP and LTP protocols.

These protocols add the following features: segmentation, encryption/authentication, and generic variable encapsulation.

Communication layers from the LPWAN networks to the application

SCAP and LTP are meant to work together on an IoT device and a server. For uplinks [^2], the data is encoded by the device-side SCAP and LTP, and then decoded by the server-side SCAP and LTP. In addition to the SCAP/LTP features, the hl2gener device-side library implements an advanced network provider management system, which improves the QoS and offers a downlink data queuing mechanism.

4.1.3. Security

  • The S in IoT stands for security
  • - Chris Romeo - IoT-Inc
  • The IoT suffers from the image of a poorly secured solution because it always have to make a trade-off between security, range, battery-life, maximum payload, etc. Thanks to the patented SCAP/LTP segmentation, it is possible to add a strong security with a minimal down-side.

    Here is a preview of the different security features provided by the LPWAN networks and SCAP/LTP:

    Feature Sigfox LoRaWAN SCAP
    anti replay low medium high
    authentication low medium (32 bits CMAC) high (AES-GCM 96 bits)
    encryption low and optional medium (AES-128) high (AES-GCM-256)

    SCAP/LTP brings a strong security to your application.

    4.1.4. Application fast development

    Designing an application is straightforward thanks to the following points :

    • The variable oriented API provides an efficient way to built an application. Instead of building obscure and unmaintainable buffers, simply describe what your devices send and your application server will receive this.

    • All the network related work is reduced to a simple configuration.

    SCAP/LTP helps you to focus on the added value you build.

    4.1.5. No provider lock-in

    Using a provider-independent layer allows you to switch from a provider to another (public or private) easily. The application is not specifically designed for a given network and switching from a network technology to another is made at no cost.

    • The SCAP/LTP route management service allows to switch from a route to another. This configuration does not impact the application.

    • The SCAP/LTP segmentation removes the need of a high throughput network, switching to a lower throughput network (e.g. from LoRaWAN to Sigfox) may have no impact on the application.

    SCAP/LTP helps you to easily adapt your applications to the technology and market changes.

    4.1.5.1. QoS improvements

    Using several auto-chaining providers increases the QoS.

    Using a theoretical - and extremly low - success rate of 90.00 % and considering that all providers are independent, this is the total success rate depending on the number of providers:

    • 1 provider: 90.00 %

    • 2 providers: 99.00 %

    • 3 providers: 99.90 %

    • 4 providers: 99.99 %

    In practice, subscribing to several providers may be expensive, the common multi-providers solutions are:

    • Use a private LoRaWAN infrastructure (the global cost is high but the cost per device is low) backed by a public provider

    • Use basic plans for fallback providers: a provider may provide several subscription plans depending on the network usage. A fallback route does not use a lot of data.

    The LoRaWAN network reduces to maximum payload size when increasing the radio performances (it says fewer words when it shouts). Thanks to the automatic segmentation, the datarate and the maximum payload are not correlated: you can use the best radio performance settings without reducing the application maximum payload.

    SCAP/LTP helps you to build a robust application.

    4.1.6. Glossary

    4.1.6.1. LPWAN

    • Low Power Wide Area Network, namely Sigfox and LoRaWAN for now

    4.1.6.2. ULP

    • Ultra Low Power. A device may typically consume less than 1 A when idle, and less than 100 mA when acquiring data and sending it through the LPWA network

    4.1.6.3. MTU

    • Maximum Transfer Unit. The maximum payload size (typically in bytes) which may be sent at once

    4.1.6.4. IV

    • Initialization Vector. A value of a predefined size which but be different each time it is used.

    4.1.6.5. join

    • When using the LoRaWAN networks, a device must join the network before sending messages. When a device switches from one LoRaWAN network to another, it must join the new network and forget the old one. Alternating between a LoRaWAN network and a Sigfox network does not require to join the LoRaWAN network at each uplink

    4.1.6.6. REST

    • REpresentational State Transfer. Here, the REST API is a set of context-less HTTP requests using the json format

    4.1.6.7. API

    • Application Programming Interface. Here, the REST API is a set of context-less HTTP requests using the json format

    4.1.7. QoS

    • Quality of Service. Here, it refers to the received segments/sent segments ratio

    1. Depending on the communication rate. A sensor typically sends data 1 to 4 times a day 

    2. When data flows from a device to a server, this is called an uplink, When the data flows from a server to a device, this is called a downlink