GSM and CDMA are competing cellular wireless technologies used by carriers that support machine-to-machine (M2M) communications. Understanding the difference between the technologies can help M2M users evaluate which carrier best fits their needs.
Aeris Communications provides network and data analytics services for M2M applications for our customers using both technologies, including the 2G and 3G GSM and CDMA family of cellular technologiesthe predecessors to the 4G cellular technology, called LTE, currently in deployment.
In the U.S., CDMA (code division multiple access) is used by the carriersSprint, Verizon and U.S. Cellular, and thus has the more dominant position. AT&T and T-Mobile use GSM (global system for mobile communications). Globally, GSM is the most-used standard, with more than 80 percent usage.
The Aeris white paper, GSM v. CDMA: Technical Comparison of M2M Technologies, offers an in-depth explanation of both technologies, their origins, and their makeup.
GSM is a standard created by the European Telecommunications Standards Institute (ETSI) to describe protocols for second generation (2G) digital cellular networks used by mobile phones. It was developed as a replacement for first generation (1G) analog cellular networks, and originally supported a digital, circuit-switched network optimized for full duplex voice telephony. It was later expanded to include data communications, first by circuit-switched transport, then packet data transport via GPRS (General Packet Radio Services) and EDGE (Enhanced Data rates for GSM Evolution or EGPRS). The 3GPP established third generation (3G) UMTS standards, and then fourth generation (4G) LTE Advanced standards.
CDMA is a communication channel access concept that employs spread-spectrum technology and a coding scheme (where each transmitter is assigned a code). CDMA also refers to digital cellular telephony systems that use this multiple access scheme, developed by Qualcomm, and W-CDMA by the International Telecommunication Union (ITU), which is used in GSMs UMTS.
In the U.S., the 2G GSM / GPRS, 2G 1XRTT and 3G EV-DO networks provide the largest physical coverage footprint for cellular service today.
Internationally, 2G GSM / GPRS services are far more common than 2G or 3G CDMA technologies, and this service is projected to operate for much longer than in the U.S.
However, as noted in the Aeris whitepaper, AT&Ts 2G GSM Sunset, the 2G GSM network is being shut down in a few years by AT&T, the largest provider of that servicethe 2G CDMA network is expected to operate much longer.
From a technology perspective, both technologies are similar in their support of cellular text and IP data servicesalthough there are clear data rate differences.
However, in most M2M applications, the technology performance is not a major factor todayeventually, the availability of much higher data rates and lower latency from 4G LTE will make that a preferred platform in the future.
Thus, for M2M devices, the choice of whether to use CDMA or GSM devices and services is generally dependent on the needs of the application, the cost of radio modules, SIM handling and management capability, deployment locations, and technology service longevity. A few Aeris customers choose to deploy both families of cellular radiosusing CDMA in the USA and GSM elsewhere in the worldfor their M2M applications.
Contact Aeris firstname.lastname@example.org or 1-888-GO-AERIS for more information.
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