Cellular IoT: A Comprehensive Overview

This section provides a tutorial on Cellular IoT (Internet of Things).

Introduction to IoT

We are all familiar with the internet, a network of interconnected computers designed for sharing information and resources. It’s essentially an Inter-Connection of Networks. Traditionally, the internet primarily connects people.

The Internet of Things (IoT) expands this concept by connecting “things,” devices, and objects to the internet, as illustrated in Figure 1. IoT has shifted the focus from merely connecting people to connecting everything. In its simplest form, IoT can be defined as extending the current internet to enable connection, communication, and interaction between physical devices or “things.”

The IoT market is experiencing rapid growth. According to Cisco, there will be approximately 50 billion connected devices using IoT technology by 2020. To achieve this, wireless devices and networks will be adapted to support IoT.

As depicted in Figure 1, sensors are interfaced with an IoT device. This IoT device can connect to a PAN (Personal Area Network), LAN (Local Area Network), Wi-Fi (Wireless LAN), or a cellular network. The cellular network can be any existing one, such as GSM, LTE, or CDMA.

Because an official IoT standard is not yet finalized, companies are working towards making their existing IPs (Intellectual Property) compliant with IoT requirements. Changes will primarily occur at the physical layer, while the upper layer protocol stack will largely remain the same.

In the network architecture, as shown in Figure 1, the IoT device connects to a device gateway, which in turn interfaces with the internet via a WAN (Wide Area Network) connection. This setup allows two IoT devices to communicate with each other.

IoT Applications

IoT applications are vast, with significant potential in sectors like medical, retail, industrial, and automotive.

IoT can be conceptually divided into four layers:

1. Sensing and Identification Layer: This layer deals with data acquisition from sensors and identification of devices.
2. Network Construction: This layer focuses on converting data into a format suitable for wireless cellular connection or any other required network.
3. Information Processing: This layer handles the processing and analysis of the data received.
4. Application Layer: This layer provides the interface for various IoT applications.

Major IoT Device Requirements

Figure 2 illustrates a typical IoT device. These devices are usually battery-powered and need to operate for extended periods. The physical layer might require modifications to accommodate the conversion of sensor data into a format suitable for transmission over a cellular network.

Companies are striving to meet the following key requirements to ensure the success of IoT devices in the market:

• Long Battery Life: Devices should ideally operate for at least 10 years on a single battery.
• Improved Receiver Sensitivity: Better receiver sensitivity compared to standard devices is crucial.
• Scalability: The system should support a large number of devices.
• Low Cost: The cost should be less than $5 to capture a significant market share.

Companies like Ericsson and Huawei are taking the lead in providing cellular solutions to meet the extensive needs of IoT devices. Ericsson is focusing on GSM and LTE, while Huawei is exploring narrowband M2M solutions based on the FDM (Frequency Division Multiplexing) concept.