Thread and Multi-Protocol Solutions for the IoT

The emergence of the Internet of Things (IoT) and emerging wireless connectivity technologies are changing the protocol landscape. Value in integrating end-device (sensor) data with operational systems and different domains is presenting new opportunities for wireless protocols to be used in a variety of systems.  Today, sensors and measurement devices are the primary wireless protocol users. The protocol and connectivity requirements vary across the network hierarchy based on application need which defines parameters such as range, power consumption, reliability, data rate, security, and addressing.  The most common wireless technologies include 802.11.x Wi-Fi, Bluetooth, Cellular, proprietary unlicensed ISM radio and 802.15.4 based protocols such as ZigBee.

These protocols serve various purposes and each protocol has advantages and disadvantages.  Bluetooth, for instance, has a limited range of about 30 feet, and devices can only connect in pairs of two. This limits the usefulness of Bluetooth in applications like smart homes because it makes managing multiple smart devices much more difficult.  Wi-Fi is a good choice when high-bandwidth is a requirement but it is not ideal for “always on” battery operated applications due to higher power consumption.  The ZigBee protocol has seen adoption in home and lighting applications, however, it is not IP addressable, can be cumbersome to implement and is not as standardized as consumers would like. To address these gaps in the protocol landscape, the Thread networking protocol was created in 2014.

The Thread stack is based on the IEEE 802.15.4 standard (Fig 1) operating at 250Kbps in the 2.4GHz band.  It is an open standard for reliable, cost-effective, low-power device-to-device communication. It is designed specifically for applications where IP-based networking is desired.

Figure 1: Protocol Stack Comparison

The following sections provide an overview of the Thread protocol –advantages, applications and use cases where Thread will be used in a multi-protocol environment.  Further, Arrow’s offerings for chip and module level designs are provided.

Overview of the Thread Protocol

The Thread stack is based on the IEEE 802.15.4 standard (Fig 2) operating at 250Kbps in the 2.4GHz band.  Using 6LoWPAN protocol for IP addressability, Thread allows devices on the network access Wi-Fi via a router, and communicate with each other.  Over 250 devices can be connected to a single network. While Thread was primary built for home automation, it is finding relevance in several industrial settings such as street lighting, and building automation.  These applications can leverage Thread’s strengths in direct device addressability and no-single-point of failure advantage.  

Figure 2a: Thread Protocol Stack Figure 2b: A Thread-Based Home Network

Advantages of The Thread protocol include: 

• IP addressable: Direct addressability to all devices – device to device or device to cloud.   Seamless connectivity to user interaction on device of choice in the home (dedicated display, smartphone, tablet, etc.)
• Simple network installation, start-up and operation: Simplified commissioning process, devices can come and go from the network and can be easily removed permanently. Further, management is simplified as Thread Networks allow systems to self-configure and fix routing problems as they occur.
• Secure: Devices do not join the Thread Network unless authorized and all communications are encrypted and secure. Banking-class AES security and commissioning features are included across all layers of the IP stack. 
• No single point of failure: The stack provides secure and reliable operations even with the failure or loss of individual devices.
• Low power: Host devices can typically operate for several years on AA type batteries using suitable duty cycles. Interoperability with a wide variety of applications.
• Flexibility with application layer:  Thread does not define the Application Layer.  This gives Thread-based implementations flexibility to implement industry standards such as ZigBee, Weave, All Joyn, and IoTivity (Figure 3).
• Fast growing network: Since The Thread Group was formed in 2014membership comprises 300+ industry leaders across consumer and industrial segments.  This fast growing network points to a fast adoption rate and the wide variety of Thread-based products that will launch in the coming years.
• Certifiable:  Starting in Q4’16, Thread-based products can be certified.  This will ensure interoperability with other Thread devices across many domains and application segments.

Figure 3:  Thread Offers Flexibility to Include any Application Layer

Multi-Protocol Environment with Thread

The evolving nature of IoT requires devices to support multiple protocols to stay competitive and increase market acceptance.  To enable multi-protocol implementations, Silicon providers like NXP offer chips and modules (directly or via eco-system partners) that support multiple wireless standards including Thread, Bluetooth, ZigBee and others.  Below are use-cases for enabling multiple protocols on a single platform.

1. Future proof technology:  ZigBee is a dominant protocol in applications such as lighting and Thread will quickly become a prevailing player in the lighting market.  OEMs need to future-proof their products and combine both options so they keep future options open with no extensive re-design and time-to-market trade-offs.
2. Gateways, hubs, and routers:  Gateways serve as integration points for various data nodes like sensors, meters, and controls across multiple domains (ex: HVAC, lighting, security, appliances, etc.).   Further, they act as crucial connectivity enablers to remote application platforms.  To support these functions, gateways must support multiple protocols to interface seamlessly with many applications and products. 
3. Bluetooth or NFC commissioning of Thread-based products:  All devices must be initially provisioned and configured for access and connectivity. This initial set up can be highly resource intensive and often lead to user-frustration and security and authentication problems. Compounding the challenge, many of the end devices operate with minimal resources and may not have traditional input interfaces like keyboards and rich displays that make commissioning easier. As device manufacturers explore easier mechanisms for initial commissioning of Thread devices – Bluetooth or NFC can be a preferred mechanism for commissioning devices and easily add them on to the network. 
4. Capability both for remote and local management:  By combining point-to-point interfaces (like Bluetooth) with networked protocols (like Thread) offers users flexibility to control or monitor devices locally or remotely.  Products like door locks and HVAC systems can be controlled locally with a smartphone using Bluetooth, or remotely managed via Thread. 

Arrow-NXP Solutions for Thread

IP-addressability, no single point of failure, flexible application layer, secure authentication, and commissioning are advantages that will propel the adoption of Thread.   While it is hard to predict the adoption rate, expectations for Thread are high.  OEMs will benefit from incorporating Thread into their products as a means to future-proof their applications and avoid costly design re-spins or worse, miss the market window. 

Arrow Electronics provides expertise, resources, and products to help OEMs successfully implement Thread into their latest designs.  Arrow is closely aligned with NXP to offer OEMs a wide selection of Thread based devices.   In addition, Arrow is a Thread Member and is committed to developing the market for Thread. The table below summarizes the Arrow’s NXP-Based Thread offerings.

Table 1: Summary of Arrow’s NXP-Based Thread Offerings

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