MIPI specifications in the Internet of Things

MIPI IoT White Paper: Enabling the IoT Opportunity

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Contents

Executive Summary
1. Introduction
2. Defining the “Internet Of Things”
     2.1. What is the Internet of Things?
     2.2. The IoT Opportunity
     2.3. The IoT Market
3. Meeting Key IoT Needs
     3.1. Technical Advantages
     3.2. Commercial Advantages
4. Specifications for the IoT
     4.1. Mapping IoT Requirements to MIPI Specifications
     4.2. Brief Overview of the MIPI Specifications
5. Example Use of MIPI Specifications in IoT
     5.1. MIPI—In the Smart Home 
     5.2. MIPI—In Consumer IoT
     5.3. MIPI—In Wearables
     5.4. MIPI—In the Smart Factory
     5.5. MIPI—In the Smart City
     5.6. MIPI—In Healthcare
     5.7. MIPI—In Utilities
     5.8. MIPI—In Drones
     5.9. MIPI—In Smart Agriculture
6. Conclusion
Annex A. Overview of MIPI Specifications (Download the PDF)

 

Executive Summary

In Brief

MIPI interfaces are used to connect sensors, cameras, displays and other key electronic components. Readily available and used ubiquitously within smartphones, many MIPI interfaces can be highly beneficial for use in IoT devices that require high bandwidth, low power consumption and low electromagnetic interference.

The Internet of Things (IoT) and its unprecedented integration of the physical, social and digital worlds are set to enhance the lives of virtually every citizen on the planet and unleash global economic growth. Technological advances in the electronics, telecom and software industries underpin the rollout of the IoT. Expanded wireless connectivity, smaller, faster and more power-efficient electronic components and more capable software are fueling a highly competitive IoT device market that

is expected to double in size to over 24 billion devices by 2025.1 It is essential that developers understand the technology building blocks available to them and make the best choices to ensure technical and commercial success.

MIPI Alliance’s specifications can help developers produce winning IoT device designs, with a portfolio of physical layer, protocol layer, software, test and debug specifications that are already ubiquitous for connecting sensors, cameras, displays and other key components in smartphones. A whole ecosystem of components, software and tools has developed around the use of MIPI’s interfaces delivering high bandwidth, low power consumption and low electromagnetic interference (EMI). MIPI is augmenting its portfolio with the launch of a new generation of specifications and software tools for helping IoT developers optimize device designs, including:

  • The recently released MIPI I3C interface (the successor of the hugely successful I2C interface) that is specifically designed to connect the latest sensors, actuators and controls
  • The MIPI A-PHY physical layer specification, which meets the needs of specific IoT use cases requiring long reach (up to 15m), high reliability and low latency
  • New software resources for a variety of specifications, including a Linux-based I3C host controller interface driver, and additional software discovery and configuration tools

More information on MIPI Alliance and its specifications can be found at www.mipi.org

Introduction

This white paper describes MIPI specifications that are most relevant to the rapid growth of the IoT over the next five  years. It is intended to show how the specifications can help satisfy key engineering design goals such as low hardware/ development costs, very low power consumption, long product life-cycles and security. After reading the paper, technical design engineers and managers should have a high-level understanding of the relevant MIPI specifications and be able to determine which specifications are potentially applicable to their target IoT device designs.

Defining the “Internet Of Things”

2.1. What is the Internet of Things?

There is no uniform industry definition for the IoT, despite efforts within the research and academic communities. The principal challenge being wrestled with when trying to agree upon a definition is how to resolve and encapsulate the huge, diverse set of potential IoT use cases covering the huge, diverse set of industries enveloped by the IoT.
For the purpose of this paper, we will assume a simple, high-level definition suggested by the Gartner research and advisory company:

“The Internet of Things (IoT) is the network of physical objects that contain embedded technology to communicate and sense or interact with their internal states or the external environment.” 2

2.2. The IoT Opportunity

The IoT offers the vision of a hyper-connected world where practically all physical objects and people seamlessly interconnect, exchanging data and making insightful decisions using artificial intelligence for the benefit of both individuals and society as a whole. Many IoT services already are widely adopted in the market today, with use cases covering virtually all sectors including automotive, consumer electronics, enterprise, healthcare, industrial, smart buildings, smart cities, smart homes and utilities.

IoT white paper - Figure 1

FIGURE 1
Global IoT Connections by 2025 (Estimated).
Source: GSMA Intelligence3

While the ultimate scale and impact of the IoT is not in doubt, the timescale for such a vision to be realized is in   question. In the past, a key factor inhibiting growth was the need for widespread and cost-effective, machine-centric wireless connectivity, but solutions are quickly becoming ubiquitous with the advent of today’s wide-area 4G and 5G cellular networks. IoT-centric connectivity is also becoming mainstream, including low-power-wide-area technologies such as LTE-M (Long Term Evolution for Machines), NB-IoT (Narrowband IoT) and LoRaWAN (Long Range Wide Area Network), and local area wireless technologies such as Bluetooth® LE, Wi-Fi®, Zigbee®, Z-wave® and Thread®. Future 5G network upgrades—introducing support for massive machine type communication (mMTC), ultra-reliable low-latency communications (URLLC) and ultra-high device densities—will be deployed in the coming years to accelerate IoT market growth.

With IoT-optimized, wireless network connectivity in place globally, new key factors influencing the growth of IoT services have taken the fore:

  • A valid business case—Can sufficient value be generated from the service?
  • Technical feasibility—Can a solution be developed within the power, size and cost constraints defined within the business case?
  • Market adoption—Can the end customer realize the value of the service?

MIPI specifications, through adherence to critical technical and commercial attributes for the smartphone industry (and described in Section 3 of this paper), help IoT developers address many of the challenging power, size and cost constraints demanded of their devices by many new and emerging IoT business cases.

IoT white paper - Figure 2

FIGURE 2
IoT connections 2019 to 2025 (includes impact of COVID-19 on the market)
Source: Source: GSMA Intelligence5

2.3. The IoT Market

The IoT market is expected to rapidly grow in all industry sectors over the next five years. According to the Ericsson Mobility Report4 published in June 2020 and the GSMA Intelligence IoT Connections Forecast5 published in June 2020 (which includes the impact of the COVID-19 pandemic on the IoT market as shown in Figure 2), the number of IoT device connections across all IoT markets is forecast to exceed 24 billion devices by 2025. This figure includes all types of IoT devices from all industry sectors and across both consumer and enterprise applications.

The breakdown of these headline figures by IoT market sector is also highly relevant to ascertain which sectors and  use cases are driving significant growth. According to the GSMA Intelligence report6 the principal sources of growth in consumer IoT are forecast to come from smart home, consumer electronics, wearables and smart vehicles sectors, as shown in Figure 3.

IoT white paper - Figure 3

FIGURE 3
Consumer IoT connections (adjusted to include impact of COVID-19)
Source: GSMA Intelligence6

IoT white paper - Figure 4

FIGURE 4
Enterprise IoT connections (adjusted to include impact of COVID-19)
Source: GSMA Intelligence7

In the enterprise IoT market, the GSMA Intelligence report7 forecasts that the key areas of growth are in the smart buildings, utilities, retail, smart city, manufacturing and health sectors, as shown in Figure 4.

2.3.1. Consumer IoT Categories

This section provides an overview of some consumer IoT vertical sectors and categories where use of MIPI specifications is highly applicable. This section is not intended to be a definitive guide to each vertical sector but to give a little more detail on the types of IoT devices that fit in each sector.

2.3.2. Enterprise IoT Categories

This section provides an overview of some enterprise IoT vertical sectors and categories where use of MIPI specifications  is highly applicable. Again, this section is not intended to be a definitive guide but to give a little more detail on the types of IoT devices that fit in each sector.

IoT white paper - Table 1

TABLE 1
Consumer IoT categories

IoT white paper - Table 2

TABLE 2
Enterprise IoT categories

2.3.3. IoT Use Cases

The scope of IoT use cases is huge, covering numerous different consumer and enterprise market sectors as described in the previous section. To help showcase the use of MIPI specifications in a variety of IoT services, we have selected nine example market sectors, each covering several IoT device use cases. A summary of use-case examples detailed later in this paper is shown in Figure 5.

IoT white paper - Figure 5FIGURE 5
Summary of IoT use case examples contained in this paper

Additionally, when selecting the example IoT use cases for inclusion in this paper, we applied the following criteria:

  • The IoT use case must require connected devices that use embedded electronics (such as microprocessors, sensors, actuators and communication hardware) to collect, share and act on data they acquire from their local environments.
  • The IoT use case must require connectivity. The connectivity can be direct to a network access point or “multi-hop” via a gateway device and provided by public or private network.
  • To avoid duplication with traditional MIPI use cases centered on mobile devices, we will exclude smartphones, tablets, laptops and other traditional personal computing devices from the IoT use cases.
  • Embedded (by OEM) smart vehicle services, although within the stated IoT definition, are excluded from this white paper because the use cases are already documented in another MIPI Alliance white paper, “Driving the Wires of Automotive.”9 Aftermarket automotive products and services are still within scope.

Meeting Key IoT Needs

MIPI Alliance develops and maintains a set of interfaces and protocols to connect the key embedded electronic components within electronic devices, including those for the IoT. The mission of MIPI Alliance is simple: to provide the key interface specifications, conformance test suites, debug tools, software and other resources that developers need to create state-of-the-art, innovative, connected devices—accelerating time to market and reducing costs.

3.1. Technical Advantages

Aligning to this mission, MIPI specifications are developed according to a set of technical attributes to ensure they support the key design goals of the mobile and mobile-influenced markets: high-bandwidth (highly scalable) performance, low power consumption and low EMI.

3.1.1. High Bandwidth

MIPI specifications define high-speed, highly scalable, flexible, ultra-low-latency interfaces for connecting electronic systems and components. Key for many IoT devices, the interfaces provide highly data-efficient modes of operation to support the requirements of a wide range of imaging and sensing components, from the most advanced cameras to the most basic, low-speed sensor components. MIPI specifications enable developers to optimize their connectivity solutions to address particular use cases—whether a high- or low-bandwidth application.

3.1.2. Low Power Consumption

MIPI specifications have been designed from the outset to enable highly power-efficient and flexible data transmission among components. In this way, the specifications enable very low power consumption in both “active” modes where data is being sent and received, in ‘’active-standby” modes when data transmission is low and interrupt-driven and ‘full- standby” mode when there is no data transmission.

With high energy-efficiency, MIPI specifications can enable an IoT device to be powered from a battery over many years or be powered from a constrained power source such as solar or wind energy.

3.1.3. Low EMI

With the drive toward designing ever-smaller devices, with the tighter packaging of components and less room for electromagnetic shielding, internal device interfaces must produce minimal levels of EMI. Many IoT devices need to meet strict EMI design goals to ensure both product reliability and to adhere to strict, sector-specific electromagnetic compatibility (EMC) regulations, particularly in health, industrial and automotive applications.

MIPI specifications help reduce EMI through a combination of factors, including low-voltage swings on high-speed physical layers and the support of slew rate control—giving developers the flexibility to adjust the EMI profile of the physical layer interface to the EMI needs of the end device. Where necessary, MIPI Alliance has developed specific solutions (such as A-PHY for the automotive industry) to meet the EMI needs of specific industry sectors.

MIPI sets lower EMI targets as new specifications are delivered and seeks to lower the EMI properties of its interfaces whenever current specifications evolve—a good example being the next revision of the MIPI SoundWire interface, SoundWire I3S (SWI3S), which targets lower EMI to minimize cross-coupling noise within audio applications.

3.2. Commercial Advantages

In addition to the technical attributes of MIPI specifications, they also serve to support the commercial aims of the IoT market as they drive economies of scale, have low cost of ownership, reduce design complexity, aid software development, are 5G ready and enable security.

3.2.1. Drive Economies of Scale

A commercial benefit of leveraging MIPI hardware and software interfaces is that they ensure interoperability between the different electronic components and products that support the specifications. This interoperability, in turn, drives huge economies of scale within the market.

To ensure interoperability is achieved, MIPI Alliance develops and maintains conformance test suites that MIPI members use to test that their implementations are conformant with the specifications. This resultant interoperability provides major benefits to the IoT market:

  • It removes market fragmentation and drives the industry toward common technical solutions. This, in turn, drives economies of scale within the electronics component market—eliminating unnecessary implementation costs within the vendor community, reducing integration costs within the developer community and enabling non- recoverable engineering costs to be amortized over large volumes of components rather than just a few.
  • It allows customers to source the components for their IoT device designs from different vendors, based on price and performance, knowing that the overall solution design will function based on the use of compatible interfaces and protocols.
  • It allows customers to dual-source components to give supply-chain flexibility and ensure continuity of supply should the supply chain be impacted.
  • It drives up quality and reduces errors, through use of industrywide conformance testing processes and the use of bug reporting schemes to ensure that any errors within the specification are addressed across the industry.

3.2.2. Low Cost of Ownership

MIPI specifications are designed from the outset to be developer-friendly, resulting in a low overall cost of ownership. Wherever possible, MIPI Alliance aims to:

  • Produce comprehensive connectivity solutions covering physical and protocol layers with associated common software components, conformance test suites and debug interfaces.
  • Ensure its technical specifications are both backward and forward compatible. Use of evolutionary, “long-lived” specifications means that developers do not have to learn completely new skillsets for each new release and also enables developers to maximize any investment in existing test suites.
  • Support devices that have long lifecycles and that may require developer support for many years within the market (e.g., for automotive and embedded smart building technologies), by ensuring the core specifications will be supported for long periods and that upgrade paths are readily available should they be required (e.g., if a sub- component needs to be replaced many years into a support contract).
  • Ensure its specifications are subject to a well-defined, royalty-free (intellectual property rights (IPR) policy.

3.2.3. Reduce Design Complexity

MIPI Alliance delivers high-performance serial interfaces, using a minimum number of wire conductors to allow chip, device and module manufacturers to minimize pin counts—leading to fewer interconnections on chips and across printed circuit boards. The resulting reduced complexity cuts manufacturing costs, supports ever-tighter packaging of components inside ever-smaller devices, and reduces weight—enabling new use cases to be addressed in the IoT space.

3.2.4. Software Development

Use of MIPI interfaces can accelerate software development and reduce development effort.

There are large numbers of developer kits and reference design boards available from multiple vendors that support the MIPI CSI-2 and DSI-2 interfaces. These kits are supported by software development resources (drivers, open source sample code, tutorials, etc.) as described in a recent MIPI blog article10.

The MIPI Software Working Group develops software resources to streamline the integration of MIPI protocols. These include the MIPI DisCoSM specifications, which aid the discovery and configuration of many MIPI protocols, and a MIPI I3C HCISM (Host Controller Interface), which provides an open source implementation of an I3C master controller for use in system-on-a-chip (SoC) designs.

3.2.5. 5G Ready

MIPI Alliance is future focused, producing specifications that will meet the demands of forthcoming market and technology requirements. The MIPI white paper11 “Making the 5G Vision a Reality: A 5G Readiness Assessment of MIPI Specifications” explains how existing MIPI specifications are capable of supporting 5G services, which will include 5G IoT devices. The paper explains how MIPI will support new 5G IoT capabilities:

  • Enhanced Mobile Broadband: Supporting gigabit peak data rates and per-device data rates of 100 Megabits per second (Mbps).
  • mMTC: Supporting ultra-high IoT device densities of up to 1 million devices per km2 and ultra-low power IoT communications.
  • URLLC: Supporting safety-critical applications that have strict requirements for throughput, latency and availability

3.2.6. Security

There are many important security issues that need to be considered when implementing an IoT service, as described in IoT security guidelines such as ETSI EN 303 64512, NIST IR8259a13 and guidelines from other organizations. Virtually all the guidelines state that it is critical for IoT developers to perform security risk assessments and then implement appropriate attack-mitigation strategies for new IoT services at the outset of their development. With security always being more costly to retrofit into a design, failing to follow best practice or make the right security choices will inhibit the successful deployment of new IoT services.

Industry IoT security guidelines recommend a multi-layer approach to address common risks, meaning that security mechanisms should, wherever possible, be considered within all layers of a device’s protocol stack. It is clear from the guidelines that simply adopting a traditional, internet-style security approach of implementing security only at the Internet Protocol (IP) communication layer will be insufficient to address many of the attack models that are specific to IoT services.

MIPI Alliance recognizes that security is critical to the success of many IoT use cases. These security challenges are particularly acute for the physical attack scenarios (i.e., the cases where IoT devices are physically “opened up” by the attacker and internal interfaces accessed) that many IoT devices are likely to be subjected to—particularly IoT devices that must adhere to functional safety standards.

The MIPI Security Group is overseeing the development of a MIPI security framework that will steer the development of new security capabilities across the suite of MIPI specifications—providing a pathway for IoT developers to implement multi-layer security into future IoT devices and helping them adhere to the most stringent guidelines. The initial framework will focus on the authentication of connected devices, and the confidentiality and integrity protection of messages sent from an application processor host to its suite of connected peripherals, such as cameras and displays.

While differentiated from security, the support of functional safety requirements for automotive applications and the support of content-protection requirements (such as High-Bandwidth Digital Content Protection) for display applications also are being addressed within MIPI’s technical working groups.

Specifications for the IoT

MIPI Alliance currently maintains numerous specifications that are beneficial to the development of IoT devices. The specifications cover physical, protocol and software layers and are applicable for use within all types of IoT devices. The specifications define interfaces that connect application processors to sensors, cameras, displays, audio, storage, actuators and other components. The majority are augmented with conformance test suites, readily available test tools, software and debug interfaces, allowing IoT developers to focus their engineering resources on product differentiation and reduced time to market, rather than on the basic development of these core underlying technical interfaces.

IoT white paper - Table 3

IoT white paper - Table 4

TABLE 3
Examples of typical IoT device requirements

TABLE 4
Summary of MIPI specifications applicable to IoT devices
Note: The Annex is available in the PDF version of the paper.

In short, if the answer to any of the following questions regarding an IoT device is “Yes,” then the device is highly likely to benefit from the use of MIPI specifications:

  • Does the IoT device require a sensor and/or actuator?
  • Does the IoT device require a camera?
  • Does the IoT device require a simple user interface (e.g., using switches, LEDs, small dot matrix display or buzzer)?
  • Does the IoT device require an advanced display (e.g., using high-resolution display and potentially a touchscreen)?
  • Does the IoT device require advanced audio (e.g., high-quality speakers and/or microphones)?
  • Does the IoT device developer require debug capabilities during the design of the device?
  • Does the IoT device require an integrated wireless communication capability?
  • Does the IoT device require low powered interfaces (e.g., to enable extended battery-powered operation)?
  • Would the IoT device benefit from reduced pin counts (e.g., to enable a compact design)?
  • Is EMI a concern?

4.1. Mapping IoT Requirements to MIPI Specifications

Mapping the requirements for some example IoT device types that fit into the different markets mentioned in Section 3.3, it quickly becomes apparent how broadly applicable MIPI specifications are to the many different types of IoT devices, as illustrated in Table 3.

Figure 6 shows the typical use of MIPI physical and protocol layer specifications within a hypothetical, generic IoT device with wireless connectivity that requires all the capabilities stated in Table 3.

IoT white paper - Figure 6

FIGURE 6
Example use of MIPI specifications in a generic IoT device with cellular connectivity

IoT white paper - Figure 7

FIGURE 7
Mapping between IoT use case categories, device types and MIPI specifications

Example Use of MIPI Specifications in IoT

This section contains a set of example IoT use cases, showing the use of applicable MIPI specifications within numerous types of IoT devices. A summary table, showing a mapping between the use case categories, device types and MIPI specifications is provided.

Preview - IoT Use Case: Smart Homes

Preview - IoT Use Case: Consumer IoT

Preview - IoT Use Case: Wearables

Preview - IoT Use Case: Smart Factory

Preview - IoT Use Case: Smart City

In the Smart Home
In Consumer IoT
In Wearables
In the Smart Factory
In the Smart City

Preview - IoT Use Case: Healthcare

Preview - IoT Use Case: Utilities

Preview - IoT Use Case: Drones

Preview - IoT Use Case: Agriculture

 
In Healthcare
In Utilities
In Drones
In Agriculture
 

Conclusion

The growth of the IoT presents huge opportunities to those organizations in both the consumer and enterprise sectors that can derive value from the tighter coupling of the physical, social and digital worlds. As with any new market there will be winners and losers, and a key factor in market success will be the successful design and development of the IoT devices upon which services depend. Those developing the most efficient, capable device designs will give themselves the best chance of market success.

In this paper, we reviewed the requirements of the devices expected to drive huge growth within the IoT market over the next five years. We found that the need for flexible, low-power and highly efficient solutions to connect the sensors, cameras, displays, audio and other components would be critical to the design of these devices. We then reviewed the

current MIPI specifications, developed for use primarily within mobile devices, and found that the key technical attributes and commercial benefits of the MIPI specifications matched closely with the key design requirements of these key IoT devices:

  • MIPI physical layer specifications (C-PHY / D-PHY / M-PHY / A-PHY) are applicable for use across a huge range of IoT devices to connect sensors, cameras, displays and enable Universal Flash Storage and inter-processor communication.
  • MIPI I3C is universally applicable for use in all IoT devices that require sensors, actuators and controls.
  • MIPI CSI-2 and its associated control interface should be the de-facto choice of camera (and other high-bandwidth sensor) interface for IoT devices.
  • MIPI DSI-2 and its in-band control protocol should be the clear choice of display interface for IoT devices.
  • MIPI SoundWire should be the leading choice of audio interface for IoT devices.
  • MIPI debug and trace interfaces and MIPI software-integration resources will accelerate any IoT device development.

More information on MIPI Alliance and its specifications can be found at www.mipi.org


1https://data.gsmaintelligence.com/research/research/research-2020/iot-co...
2https://www.gartner.com/en/information-technology/glossary/internet-of-t...
3https://data.gsmaintelligence.com/research/research/research-2019/iot-co...
Note: GSMA Intelligence definition for IoT is “Devices capable of two-way data transmission (excluding passive sensors and RFID tags). It includes connections using multiple communication methods such as cellular, short range and others. It excludes PCs, laptops, tablets, e-readers, data terminals and smartphones”.
4https://www.ericsson.com/en/mobility-report/reports
5https://data.gsmaintelligence.com/research/research/research-2020/iot-co...
6 & 7https://data.gsmaintelligence.com/research/research/research-2020/iot-co...
8https://mipi.org/mipi-white-paper-driving-wires-automotive
9https://mipi.org/mipi-white-paper-driving-wires-automotive
10https://resources.mipi.org/blog/developer-kits
11https://resources.mipi.org/5g-readiness-white-paper
12https://www.etsi.org/deliver/etsi_en/303600_303699/303645/02.01.00_30/en...
13https://www.nist.gov/publications/iot-device-cybersecurity-capability-co...