Impact of Access Barring Schemes for Delay Tolerant MTC Devices on Energy Consumption

Cellular mobile communication systems have evolved from voice-centric to universal communication systems. After release 10 of the 3GPP standard, the group started working on specific enhancements tailored for machine-type communication (MTC), e.g. improving energy consumption, coverage enhancements and support for massive number of devices per cell. During the study for MTC enhancements, congestion on the random access channel was identified as a major issue in case a very high number of MTC devices tries to simultaneously access the cell. The existing access class barring (ACB) is a threshold based approach affecting all devices in a cell. Thus a new barring mechanism for latency-tolerant MTC devices was introduced: enhanced access barring (EAB). There have been numerous publications in the last years on how to optimize ACB and EAB for throughput and latency but only very few considered the major important impact on the overall energy consumption of the devices. Unlike previous publications, this paper investigates the effect of different access barring schemes on the energy consumption of MTC devices in case of high load on the random access channel and compares static and dynamic ACB settings as well as EAB-based solutions.