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Erik Dahlgren

Communication Protocols in IoT – Part 3

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This is the third part of the series ” Communication Protocols in IoT”. The first part can be found here

Bluetooth is a technology that is probably not unfamiliar to anyone today since literally every smartphone comes with the technology as standard. But how is this technology that historically is most known for audio streaming/handsfree use cases relevant for IOT?

Early history
The roots of Bluetooth can be traced back to 1994 when an engineer working for Ericsson, Jaap Haartsen was tasked to develop a wireless alternative to RS-232 (serial cables). Similar ideas also emerged in other companies around the same time and it quickly became clear that for products from different vendors to be compatible and interoperable. Some sort of standardization was required. In 1996 five companies (Ericsson, Nokia, Intel, Toshiba, and IBM) met in Lund Sweden and agreed that a Special Interest Group (SIG) was to be formed to drive and standardize the technology. Two years later in 1998, the Bluetooth Special Interest Group (Bluetooth SIG) was officially established.

Technicalities and Standards
The Bluetooth technology standard(s) and specification(s) are governed by the Bluetooth SIG. Membership is free for any company (Adopter level) but a higher-level membership (Associate) is available for a yearly fee. Associate membership brings several possibilities for companies who wants to actively participate in working groups, have early access to new specifications and contribute to the development of the Bluetooth standard. There is also a higher (Promoter) level membership which you cannot pay for, this small group of companies consists of the most active contributors to the standard and each company has one seat on the highest governing body of the SIG, The Board of Directors.

Since the release of Bluetooth 1.0 in 1998, a large amount of work has been done to the specifications and profiles covered within Bluetooth technology and the most recent core specification (2018) is at 5.0.

To sell a product with Bluetooth branding/technology, certification is mandatory. This is mainly enforced to secure interoperability between different devices and brands. Although the certification historically has not guaranteed a 100% interoperability between every device supporting the same profile(s) on the market. It does provide a quite rigorous suite of tests and requirements to push for well-implemented products.

Protocol Basics
When talking about Bluetooth technology it is nowadays a bit problematic to talk about “one technology” due to a significant change that was introduced in the core 4.0 standard in 2010. The introduction of Bluetooth Low Energy (BLE) meant that Bluetooth now consisted of 2 different stacks from the physical layer up to the application. Some parts were of course reused and there are absolutely no problems finding chipsets that support both the traditional (Basic Rate (BR)/Enhanced Data Rate (EDR)) standard as well as the new (BLE) standard.

BR/EDR
The traditional Bluetooth stack which is still very relevant today (although maybe not so much in an IoT context) contains profiles for media streaming and control (A2DP/AVRCP), Handsfree (HFP), serial port emulation (SPP), Text message synchronization (MAP) and internet tethering (PAN) to mention some of the most commonly known profiles and use cases. All profiles are described in detail in specifications that are released by the Bluetooth SIG and all vendors are required to implement mandatory parts to enable interoperability. The maximal theoretical (not practical!) transfer speed using EDR is 3 Mbit/s (a “High Speed” (HS) standard also exist where actual data transfer is handed over to WiFi, but this is very seldom used).

BLE
Bluetooth low energy (BLE) on the other hand, was specifically developed and tailored to be used for IoT use cases. The standard offers very low power consumption with several powerful features suitable for IoT use cases.

  • Broadcasts:
    Devices can broadcast limited amounts of data even to devices that are not trusted/paired.
  • Dedicated advertising channels:
    Compared to BR/EDR, BLE uses 3 dedicated advertising channels allowing for a much quicker device discovery (scan 3 physical channels instead of 79 as is the case with BR/EDR). Limiting advertising to only 3 channels also has a positive impact on energy consumption.
  • Flexible protocol definition:
    While some common profiles defined by the Bluetooth SIG exists (Blood Pressure Profile, Heart Rate Profile and Insulin Delivery profile to name a few). BLE makes it very easy to define and create your own profile for your specific needs. By using the protocols and capabilities available in the BLE stack you can easily implement your use case(s).

To improve things further, the latest core specification (Bluetooth 5.0) and the additional MESH specification adds a few more powerful features:

  • 2 Mbit/s PHY:
    Compared to Bluetooth 4.0/4.1/4.2, it’s now possible to have 2x the maximum throughput if your IoT use case require some heavier data transfer (theoretically up to 2 Mbit/s compared to 1 Mbit/s for earlier BLE standards. It is however important to mention that these numbers are solely theoretical and deals mainly with modulation, practical data throughput is far less.).
  • 4x Range:
    The Bluetooth 5.0 standard also introduces another new PHY (Physical layer) that allows Bluetooth to achieve up to 4x the range compared to Bluetooth 4.0/4.1/4.2. Note that despite some less than clear claims during the release of the standard stating “2x the speed and 4x the range”, you can only get one of these properties at a time. You don’t get both since the PHY is significantly different.
  • Mesh:
    BLE now supports Mesh technology making it a suitable technology candidate for large-scale deployments and use cases where each edge device doesn’t need to have a direct connection to a more central node.

Use cases:
Bluetooth is a huge technology (the core 5.0 specification alone is over 2800 pages!) so it’s safe to claim that the technology can support a vast number of different use cases. This is also obvious when looking at the market. Bluetooth has an extremely impressive market penetration since its available in more or less every smartphone. A list of all even common use cases would be extremely long, but you can easily find it in everything from common products such as smart watches, fitness trackers and smart lighting to more exotic implementations in toasters, toilets, and toothbrushes.

 

//Erik Dahlgren, Software Developer

Communication Protocols in IoT – Part 2

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This is the second part of the series “Communication Protocols in IoT”, the first part can be found here 

NFC
NFC or “Near Field Communication” is a wireless technology that is used for communication over extremely small distances (WPAN category, for NFC we are talking in terms of centimeters). While “NFC” sounds like one unified technology, it could when taking a closer look more be viewed as a collection of protocols and sub-standards that lets you design your product to your needs.  

Technicalities and standards
NFC is one of many defined RFID (Radio Frequency identification) standards and operates in the 13.56 MHz ISM-band. The base standard for NFC physical layer and RF is ISO-18092 (Near Field Communication) while parts of an older ISO-14443 (Contactless integrated circuit cards) are also fully inherited or reused.
On top of the bottom layers, it immediately gets more interesting and diversified when different manufacturers and organizations have defined different protocols all the way up to the application layer.  

[Image source: https://upload.wikimedia.org/wikipedia/commons/3/33/NFC_Protocol_Stack.png]

 

While not every protocol is interesting to cover in detail in a brief overview, it is worth mentioning that that tag types (1-4 and MiFARE) and the NDEF (NFC Data Exchange Format) are very central when working with NFC in order to read, write and interpret data. 

Protocol Basics

The NFC technology can work in both active and passive mode where the passive mode is the most well-known one (think of reading data from an NFC tag/card). In this mode, NFC uses induction between the two communicating devices which gives the very nice property of one device (initiator) powering the other device. This means that a tag/card (target) does not need its own power source but is instead powered by the other device and transmits data by modulating the already generated electromagnetic field. 

NFC can also operate in active or “peer-to-peer” mode where both devices have a power source and alternates between generating an RF field (sending) and being passive (receiving). 

In terms of data transfer speed, NFC is not designed nor used to shuffle large amounts of data. A few different standards and modulation exist which allows NFC to transfer data with a bit rate of 106, 212 or 424 Kbit/s respectively.  

Use Cases
Despite being a wireless technology with an extremely short range and limited transfer speed, there are quite a few use cases where NFC is a suitable and widely adopted technology:

  • Contactless payment
    A large use case today which currently is seeing large penetration in quite a few markets. This appears in many forms, everything from public transport access cards and NFC enabled credit cards to cellphone-based payment apps.    
  • Identification
    With a very low cost for NFC tags/stickers, it’s a very efficient way of storing identification data. Everything from single shirts in a store, car parts in a factory to large containers can carry their unique information with them through the supply chain in a small and cheap tag. The fact that the only thing you need to access/read the data is a semi-modern smartphone also gives this use-case quite a boost. 
  • Access control
    The traditional badge or access card, while of course not every implementation of RFID based access control is based on the actual NFC standard. It’s easy to see why it’s a popular and fine-grained solution. Compare it to having physical keys or a key panel where a lost key/code could be very costly and/or unsecure (even with a unique code per user). An NFC card allows for instant revocation of access as well as a possibility to log who is accessing a secure/limited area at a certain time at a low cost. 
  • Bootstrapping/setup
    A quite popular use case today where NFC is used to bootstrap and simplify the setup of other wireless technologies such as Bluetooth and/or WiFi. Instead of manually struggling with pairing processes, scanning, and manual key entry, simply bring the devices to close together and setup is complete. 
  • Medical
    A growing use case today, NFC can (and is) used in everything from labeling lab samples to reading your blood glucose levels with your cell phone. 

 

 

Do you have questions about NFC technology or its use cases? Drop us an email at info@scionova.com or post in any of our social media channels. 

 

// Erik Dahlgren

Communication protocols in IoT – part 1

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This is the first part of the blog series “Communication protocols in IoT” by Erik Dahlgren.

Introduction

With an ever-growing buzz about IoT and new connected products constantly introduced to the market, it can sometimes be difficult to get a clear overview and understanding of all the underlying wireless connectivity technologies that enable these products and use cases. When is it suitable to use Bluetooth vs NB-IoT? What properties does Zigbee provide for a product? How is Thread different from Wi-Fi?  

In a series of blog posts, we will explain each communication protocol in a simple way and provide some insight into how and where these technologies are used in the industry today. 

 

Coverage areas and included protocols 

To provide some logical grouping of protocols/networks, it’s very common to divide them into groups describing their coverage or operating area. If you have ever taken a course in Networking/Communication, the expressions below should be familiar (Although the definitions can vary a bit): 

PAN (Personal Area Network): Very close proximity. Typically, a few square meters. 

LAN (Local Area Network): Historically a few hundreds of meters, it might also be suitable to think in terms of “sites”. E.g. your office or home most likely have one (or more) LAN:s. 

MAN (Metropolitan Area Network): Covering tens of kilometers, e.g. a city or metropolitan area. 

WAN: (Wide Area Network): Covering large distances, from kilometers out to space… 

As mentioned above, the definitions might vary quite a bit for several reason when we try to assign a technology into one of the categories above. Should LTE be considered MAN or WAN? And what about Bluetooth which has typically been a school book example of PAN? With the introduction of Bluetooth Mesh, we can today easily cover a whole building with the technology. To simplify and limit our scope to technologies that are interesting in an IoT-context, we will cover these groups, definitions, and technologies: 

WPAN (Wireless Personal Area Network)
-NFC (Near Field Communication)

WLAN (Wireless Local Area Network, not to be confused with “WiFi“)
-Bluetooth
-WiFi
-Zigbee
-Z-Wave
-Thread

LPWAN (Low-Power Wide Area Networks)
-LoRa
-Sigfox
-NB-IoT
-LTE cat M1

Hope you enjoyed this introduction of my blog series ” Communication Protocol in IoT”. Next time I will talk about NFC or “Near Field Communication” that is a wireless technology which is used for communication over extremely small distances.

/Erik Dahlgren, Software Developer at Scionova