TRANSACTIONS ON EMERGING TELECOMMUNICATIONS TECHNOLOGIES Trans. Emerging Tel. Tech. (2013) Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/ett.2629 SPECIAL ISSUE - M2M Analytical modelling and performance evaluation of realistic time-controlled M2M scheduling over LTE cellular networks Antonis G. Gotsis*, Athanasios S. Lioumpas and Angeliki Alexiou Department of Digital Systems, University of Piraeus, Piraeus, Greece ABSTRACT Supporting emerging machine-to-machine (M2M) communications over Long-term Evolution (LTE)/LTE Advanced cel- lular networks in an efficient way will be beneficial for both telecommunication communities. The first step to migrate to an M2M-enabled cellular standard is to provide these new services through the existing architectures and protocols, while maintaining seamless backward compatibility. To this end, we thoroughly examined a key LTE Medium Access Control entity, which is the packet scheduler, and proposed solutions based on the time-controlled M2M feature, to deal with the diverse M2M traffic characteristics and quality-of-service requirements. Starting from the single M2M class case, we extended our study to more realistic scenarios, involving more M2M classes with diverse quality-of-service require- ments. We defined analytical models for predicting the system performance on the basis of queueing theory concepts and considered the interaction between classes with different priorities. The proposed analytical models are validated through extensive system-level simulations. On the basis of the insight obtained from our analytical approach, we modified an existing scheduling algorithm to improve the performance of low-priority M2M device groups, and we demonstrated its superior performance both experimentally and analytically. Copyright © 2013 John Wiley & Sons, Ltd. *Correspondence Antonis G. Gotsis, Department of Digital Systems, University of Piraeus, 126 Grigoriou Lampraki Street, Office 501, GR18532, Piraeus, Greece. E-mail: agotsis@unipi.gr Received 28 May 2012; Revised 30 November 2012; Accepted 2 February 2013 1. INTRODUCTION The machine-to-machine (M2M) communications paradigm complementing the classical human-to-human (H2H) interaction model constitutes an emerging market, for which recent market analyses predict more than 500 mil- lion embedded M2M connections by 2014 [1, 2]. Mobile broadband stakeholders, including standardisation organ- isations, have identified the need for supporting M2M applications through cellular networks. The 3rd Generation Partnership Project (3GPP) has formed dedicated study items under the umbrella term of ‘machine-type communi- cations’ (MTC) for Release 10 and beyond [3–5], whereas IEEE has initiated the IEEE 802.16p and 802.16.1b projects oriented towards amending the latest IEEE 802.16m standard with M2M support (for example, [6]). The M2M ecosystem spans a wide range of applications, including smart metering (industrial and energy/smart grid), health monitoring and alerting, and intelligent transportation (fleet management, car-to-car collision avoidance, etc.) [7], characterised by the following: (i) the large number of simultaneously connected devices; (ii) small data volume transmissions; and (iii) vastly diverse quality-of-service (QoS) requirements compared with classical mobile broadband services. In this work, we focus on how M2M communications could be efficiently supported by current and future 3GPP mobile broadband standards beyond Wideband Code Divi- sion Multiple Access/High-Speed Packet Access, provid- ing a smooth evolution of Long-term Evolution (LTE) and LTE Advanced towards M2M-enabled cellular networks. Packet scheduling is the key radio resource management mechanism for guaranteeing QoS requirements while min- imising the overall resource usage [8]. Assuming that the existing cellular resources will initially support both H2H and M2M services and taking into account that M2M applications significantly differ from H2H appli- cations, in terms of traffic and QoS profiles, designing efficient M2M-over-LTE scheduling schemes constitutes a major challenge. Copyright © 2013 John Wiley & Sons, Ltd.