I. What are NB-IoT and eMTC?

NB-IoT: Narrow Band Internet of Things (NB-IoT) is a narrowband low-power wide-area network technology based on cellular networks, focusing on low-speed, wide-coverage, and high-connectivity IoT scenarios. It uses Frequency Division Duplex (FDD) mode, occupying 180kHz of narrowband spectrum, and can be directly deployed on GSM, LTE, or 5G networks without the need for separate network construction. NB-IoT has a maximum transmission rate of up to 250kbps, supports deep sleep mode, has extremely low device power consumption, and a transmission distance of over 10 kilometers in open areas, achieving coverage of about 5 kilometers in urban building environments. It is a core technology for the intelligentization of "dumb terminals" such as water meters, electricity meters, and gas meters.

eMTC: Enhanced Machine-Type Communication (eMTC) is an LTE enhancement technology defined by 3GPP for the Internet of Things (IoT), belonging to the category of broadband IoT. It adopts Time Division Duplex (TDD) or Frequency Division Duplex (FDD) modes, supports a 1.4MHz wideband spectrum, and has a maximum transmission rate of 1Mbps. It features low power consumption, low latency, and mobility support. Compared to NB-IoT, eMTC adds voice call and high-speed data transmission capabilities, making it suitable for IoT scenarios requiring a certain level of mobility and medium data rates, such as shared bicycles and smart wearable devices.

II. Protocol Characteristics of NB-IoT and eMTC

NB-IoT Core Features

1. Ultra-wide Coverage: Utilizing technologies such as repeated transmission and orthogonal frequency division multiplexing, it boasts extremely strong signal penetration, covering areas that traditional cellular network signals struggle to reach, such as underground parking garages, basements, and remote mountainous regions. Coverage is more than 20dB better than LTE.

2. Massive Connectivity: A single sector can support more than 100,000 terminal devices, far exceeding traditional cellular networks, perfectly adapting to large-scale terminal deployment scenarios such as smart cities and smart metering.

3. Ultra-low power consumption: Terminal devices support PSM (Power Saving Mode) and eDRX (Extended Discontinuous Receiver) modes, with sleep current as low as microamps, providing 5-10 years of battery life without frequent battery replacements.

4. Low cost: NB-IoT module chips have high integration and simple peripheral circuits, keeping module costs below $10 and eliminating the need for additional spectrum fees, significantly lowering the barrier to entry for device intelligence.

5. High reliability: Employing AES-128 encryption algorithm, it supports end-to-end data encryption and possesses anti-interference and anti-fading characteristics, maintaining stable communication even in harsh environments.

eMTC Core Features

1. Medium speed: Transmission speeds are significantly higher than NB-IoT, supporting uplink 1Mbps and downlink 500kbps data transmission, suitable for scenarios requiring image and short video transmission, such as video surveillance and smart wearables.

2. Mobility support: Inheriting LTE's mobility management capabilities, terminal devices maintain stable connections even during high-speed movement, suitable for mobile IoT scenarios such as shared bicycles and logistics tracking. 3. Low Latency: Latency can be controlled within 100ms, far lower than the second-level latency of NB-IoT, meeting the needs of scenarios requiring fast response times, such as smart parking and remote control.

4. Voice Capability: Supports VoLTE voice calls, enabling voice interaction for IoT devices, such as the one-click SOS function on elderly wristbands, expanding the application boundaries of IoT.

5. Flexible Deployment: Can be co-located with LTE networks, utilizing existing base station resources without the need for large-scale infrastructure construction, resulting in low deployment costs and short deployment cycles.

III. Network Architecture of NB-IoT and eMTC

Both are based on cellular network architecture and adopt a layered networking design. The complete architecture includes four parts: terminal equipment, base stations, core network, and application platform.

1. Terminal Equipment: Sensors or actuators integrating NB-IoT/eMTC modules, such as smart water meters and shared bicycle locators, responsible for data collection, command execution, and wireless transmission.

2. Base Station: Utilizing existing LTE or 5G base stations, software upgrades can support NB-IoT/eMTC protocols, enabling signal reception and forwarding. The base station is only responsible for radio frequency signal processing and does not participate in business logic.

3. Core Network: Core network elements include AMF (Access and Mobility Management), SMF (Session Management), and UDM (Unified Data Management), responsible for terminal access authentication, mobility management, session management, and data routing.

4. Application Platform: Includes an IoT platform and a business application platform. The IoT platform is responsible for terminal device management, data parsing, and protocol conversion; the business application platform implements functions such as data visualization, anomaly warning, and remote control according to different scenarios.

Common IoT Platforms

1. Huawei OceanConnect: Supports multiple IoT protocols such as NB-IoT, eMTC, and LoRa, providing one-stop services for device access, device management, and data analysis, suitable for enterprise-level IoT solutions.

2. Alibaba Cloud IoT Platform: Provides access and management capabilities for massive numbers of devices, supports seamless integration with Alibaba Cloud's big data and artificial intelligence services, and facilitates the intelligent upgrade of IoT applications. 3. China Mobile OneNET: An open IoT platform for developers and enterprises, supporting rapid access for NB-IoT/eMTC terminals, providing rich API interfaces, and lowering the threshold for application development.