LTE (Long-Term Evolution) radio access was initially designed for high-speed communications, taking into account high mobility and low latency for data transport.
Using LTE radio access for connected objects exposes different constraints such as battery life and terminal cost, and decreases the speed and latency requirements.
The reduction of the radio channel bandwidth is one of the factors making it possible to keep the objectives fixed for the connected objects:
- – the bandwidth is reduced to 1.4 MHz or 5 MHz for the LTE-M radio interface;
- – the bandwidth is reduced to 180 kHz for the NB-IoT (NarrowBand Internet of Things) radio interface.
The reduction of the modulation index and the absence of a MIMO (Multiple Input Multiple Output) mechanism also contribute to reducing energy consumption and lowering terminal costs.
The power saving mode (PSM), on the one hand, and the extended discontinuous reception (eDRX), on the other hand, are complementary mechanisms that reduce the terminal power consumption during standby or when the terminal radio interface and the functions relating to radio resource control (RRC) are switched off.
11.2. Special features
11.2.1. PSM feature
The PSM feature is designed to help terminals to reduce battery consumption and potentially reach 10 years of battery life.
The PSM feature is similar to a power off, but the terminal maintains the context, which avoids turning off the terminal and reconnecting ...