A Primer on 3G Modules

3G Benefit: 3G modules offers more benefits interms of speed and performance compared to the 2G modules.

  •  Compared to GPRS and EDGE modules, 3G modules offer higher downlink and uplink data rates. See speed comparision below.
  • Latenties on 3G network is considerably better than 2G networks – WCDMA (150 ms), HSPA (100 ms), HSPA+ (5ms).
  • For network operators, 3G networks provides better use of wireless spectrum compared to the 2G networks.

 3G Standards: The air interface standards for GSM-based 3G modules are developed by 3rd Generation partnership Project (3GPP) which is a collaboration between groups of telecommunication associations. For CDMA-based 3G modules, the standards are developed through 3GPP2 group.

 3G Speed: The speed of 3G modules depends on the network conditions and the performance of the device. The actual speeds are usually lower than the theoritical speeds shown below,

  Downlink (Theoritical Max Speed) Downlink (Typical Average Speed) Uplink (Theoritical Max Speed) Uplink (Typical Average Speed)
UMTS 384 Kbps 220-320 Kbps 384 Kbps 220-320 kbps
HSDPA 1.8 Mbps 500-800 Kbps 384 Kbps 200-300 Kbps
EVDO Rev A 3.1 Mbps 450-850 Kbps 1.8 Mbps 300-400Kbps

3G Frequency Bands: 3G Modules operate at varierty of frequency bands depending on the carrier network. Typically a module SKU will be configured to support certain frequency bands to operate on a certian geographic region or a certain carrier.

Operating Band Frequency band (MHz) Uplink Frequency (MHz) Downlink Frequency (MHz)
1 2100 1920-1980 2110-2170
2 1900 1850-1910 1930-1990
3 1800 1710-1785 1805-1880
4 1700 1710-1755 2110-2155
5 850 824 - 849 869 - 894
6 800 830 - 840 875 - 885
7 2600 2500-2570 2620-2690
8 900 880 - 915 925 - 960
9 1700 1749.9 - 1784.9 1844.9 - 1879.9
10 1700 1710-1770 2110-2170
11 1500 1427.9 - 1447.9 1475.9 - 1495.9
12 700 698 - 716 728 - 746
13 700 777 - 787 746 - 756
14 700 788 - 798 758 - 768
15 800 832.4 - 842.6 877.4 - 887.6

3G Module Form Factors: PCIe is the most common form factor avaialble through many module vendors. However for devices that have size constraints, modules incorporating surface mount technologies such as Land Grid Array (LGA) or Ball Grid array (BGA) offer smaller sizes. Modules with propreitery form factor are also offered by vendors. Lack of M2M module standards is one of the barriers for adoption and there are efforts underway by the indutry to address this issue.

3G Module Interfaces: Interfaces are capabilities supported by the modules through hardware and/or software. Some of the common interfaces supported on 3G modules are,

  • Power : Power interface is mandatory for all modules and the supply ranges from 3.0V – 4.5V.
  • UART (Universal Asynchronous Receiver/Transmitter):  Some host devices might use UART, though mostly it is used for debugging purpose. UART rates vary from 1200bps to 115200bps.
  • USB (Universal Serial Bus): USB is usually the primary data interface used on 3G modules since it supports higher data rates.
  • UICC (Universal Integrated Circuit Card): GSM-based 3G modules will have UICC interface which is based on IS0 7816-3.
  • Antenna: Antenna connectors are generally availble on-board the 3G modules. To improve receiver performance, a diversity antenna connector is also sometimes avaialble on the modules.
  • GPS (Global Positioning System): Many of the 3G modules have integrated GPS solution.GPS antenna port may be on a separate port or shared with the diversity antenna port.
  • SPI(Serial Peripheral Interface) :SPI interface is genrally used to connect to the external display devices.
  • I2C (Inter-Integrated Circuit Bus): I2C interface is used to communicate with external display device or storage device.
  • SDIO (Secure Digitial Input/Output): SDIO interface is used for interfacing with external SD card.
  • PCM (Pulse Code Modulation): PCM interface in 3G modules is used for digital audio transfer.
  • Analog Audio Interface: For devices that require voice support, 3G modules will provide analog audio interfaces.

3G Module Certification

Before the 3G module can be commercially used with in a device, it has go  through several certification process.

  • Global certification Forum (GCF) : GCF enables certification of any mobile device based on 3GPP technologies. GCF certification is supported by leading operators from every region of the world. GCF approval requires both conformance lab testing and field trials.
  • PTCRB : PTCRB is the North American operators certification body.It provides a framework within which device certification can take place for members of teh PTCRB.3G modules are tested at PTCRB accredited labs which manage the certification process.
  • FCC : In order to obtain a modular approval teh FCC has identified requirements that must be addressed in the application for equipment authorization. These requrirments are specified in this FCC document.
  • Network Operator Certification: In addition to PTCRB/GCF & FCC, the module should also be certified by the network operator. In fact, the network operators might have industry certifications as a pre-condition for lab entry.



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