Terminology » Mobile Communication » LTE-M Device Categories: Cat-0, Cat-M1, and Cat-M2 Explained

LTE-M Device Categories: Cat-0, Cat-M1, and Cat-M2 Explained

lte m device category cellular iot cat m1 cat m2

This article delves into the differences between LTE-M device categories: Cat-0, Cat-M1, and Cat-M2. LTE-M, which stands for Long Term Evolution for Machine-Type Communications, is built upon 3GPP specifications, much like LTE technology.

LTE-M is specifically designed to cater to the objectives of cellular IoT devices, focusing on:

  • Low device cost
  • Deep coverage
  • Extended battery life
  • High cell capacity

Let’s explore each category in detail.

LTE-M Cat-0

  • Specification: Defined in 3GPP Release-12.
  • Peak Data Rates: 1 Mbps for both Downlink (DL) and Uplink (UL). (In comparison, Cat-1 supports 10 Mbps DL and 5 Mbps UL).
  • Receive Antennas: Employs a single receive antenna. (Cat-1 utilizes at least two).
  • Duplex Mode: Optional HD-FDD (Half Duplex Frequency Division Duplex).
  • Bandwidth: Operates on a 20 MHz bandwidth.
  • Device Power Class: Rated at 23 dBm.

LTE-M Cat-M1

  • Specification: Defined in 3GPP Release-13.
  • Key Features: Builds upon the cost-reduction features of Cat-0, incorporating additional improvements.
  • Duplex Modes: Supports HD-FDD, FD-FDD (Full Duplex Frequency Division Duplex), and TDD (Time Division Duplex).
  • Peak Data Rates:
    • 800 Kbps (DL) and 1 Mbps (UL) using FD-FDD, accounting for scheduling delays.
    • 300 Kbps (DL) and 375 Kbps (UL) using HD-FDD, accounting for scheduling delays.
  • Receive Antennas: Utilizes a single receive antenna.
  • Bandwidth: Operates on a 1.4 MHz bandwidth.
  • Maximum DL/UL Bandwidth: Limited to 6 PRBs (Physical Resource Blocks), equivalent to 1.080 MHz.
  • Modulation Scheme: Employs a higher modulation scheme, specifically 16 QAM (Quadrature Amplitude Modulation).
  • DL/UL Coding Scheme: Uses Turbo code.
  • Spatial Layers: Supports a maximum of 1 spatial layer in both DL and UL.
  • Maximum TBS (Transport Block Size): 1000 bits for both DL and UL.
  • Device Power Class: Rated at 20 dBm.
  • Coverage Enhancement (CE) Modes: This category supports CE Mode-A (Mandatory) and CE Mode-B (Optional).

LTE-M Cat-M2

  • Specification: Defined in 3GPP Release-14.
  • Bandwidth: Operates on a 5 MHz bandwidth, enabling transmission in PDSCH (Physical Downlink Shared Channel) and PUSCH (Physical Uplink Shared Channel) using 24 PRBs instead of 6 PRBs.
  • TBS (Transport Block Size): 4008 bits (DL), 6968 bits (UL)
  • Peak Data Rates: 4 Mbps (DL), 7 Mbps (UL)