EC-GSM-IoT overview

EC-GSM-IoT, or Extended Coverage GSM IoT was proposed as part of the 3GPP Release 13 specification (as an eGPRS-specific feature of Release 13 of 3GPP) and it provides an additional toolset for those IoT use cases that require a better coverage, while not being so demanding of the bandwidth.

With this premise, it made sense to leverage the ubiquitous presence of GSM/GPRS, without the need for a new network infrastructure. In this landscape, proven and robust second-generation cellular technology is more than just a good combination of coverage with a low deployment cost.

For a network operator, the deployment of EC-GSM-IoT is as simple as dedicating one GSM carrier to the service, as it is an in-band technology. It can be used as part of wider frequency redeployments or farming. The standard is a set of enhancements in the air interface standards of GSM.

The achievable data rates depend on the actual modulation, either via GSMK (Gaussian Minimum Shift Keying, the original modulation of GSM) or 8PSK modulation. The basic device capability is mandated to be EGPRS MC1 to MCS4, while the support of circuit-switched functionalities or GPRS is not needed for this standard.

EC-GSM-IoT can be deployed easily on existing 2G infrastructures and the standard foresees that the enhancements in the air interface will have a minimal impact on the hardware requirements for the base station hardware. The standard does mention backward compatibility with GSM/GPRS, coexistence, and design reuse.

The receiver models proposed in the EC-GSM-IoT standard do fulfill the battery life expectation of 10 years, in most of the use cases. One of the contributors to longer battery life is the Power Saving Mode of EC-GSM-IoT.

The EC-GSM-IoT has improved security, compared to the existing GSM/GPRS networks, offers integrity protection, and mutual authentication, and requires stronger ciphering algorithms.

The latency is in the range of medium to high, as it could be derived from the known latency values of existing GSM/GPRS networks. Latency, while an important aspect of the technology choice for IoT, should not be an obstacle for certain applications.