GPRS Modem benefits: GPRS Modems enable wireless communication to variety of M2M devices.
- GPRS modems are lowest in cost compared to 3G & 4G modems.
- GPRS networks are ubiquitous, so GPRS modems works on most carrier networks through out the world.
- Carrier networks are switching to 3G & 4G networks, so many of them are phasing out support for GPRS modems.
GPRS Modem Standards: GPRS modem standard is managed by 3GPP standards body. GPRS was originally standardized by European Telecommunications Standards Institute (ETSI). The throughput and latency of GPRS netwroks depend on number of concurrent users that are on the network. GPRS is integrated into GSM Release 97.
GPRS Modem classes: GPRS modems are divided in to 3 classes,
- Class A: Can be connected to GPRS service and GSM service (voice, SMS), using both at the same time.
- Class B:Can be connected to GPRS service and GSM service (voice, SMS), but using only one or the other at a given time.
- Class C:Are connected to either GPRS service or GSM service (voice, SMS). Must be switched manually between one or the other service.
GPRS Modem Speed: Data rates of GPRS modems depends on the network conditions and performance of the device.
|GPRS||80 Kbps||20 kbps( Class 8 & 10)|
|GPRS||60 Kbps||40 Kpbps (Class 10)|
|EGPRS||236.8 Kbps||59.2 Kbps (Class 8,10)|
|EGPRS||117.6 Kbps||118.4 Kbps 9Class 10)|
GPRS Frequency Bands: GPRS modems can operate on following bands. The band configurations of the modules are dependent on the carrier network.
GPRS Modem Form Factors: GPRS modems are predominantly used in M2M applications. So the form factors have been proprietary to the vendors. However 2 common types of forms factors are connectorized module and surface mount module (LGA or BGA).
GPRS Modem Interfaces: Interfaces are capabilities supported by the modules through hardware and/or software. Some of the common interfaces supported on GPRS modems are,
- Power : Power interface is mandatory for all modules and the supply ranges from 3.0V – 4.5V.
- 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 GPRS modules will have UICC interface which is based on IS0 7816-3.
- Antenna: Antenna connectors are generally availble on-board the GPRS modems. To improve receiver performance, a diversity antenna connector is also sometimes avaialble on the modules.
- GPS (Global Positioning System): Many of the GPRS modems have integrated GPS solution.GPS antenna port may be on a separate port or shared with the diversity antenna port.
- PCM (Pulse Code Modulation): PCM interface in GPRS modem is used for digital audio transfer.
- Analog Audio Interface: For devices that require voice support, GPRS moedms will provide analog audio interfaces.
GPRS Modem Certification
Before the GPRS modem 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.