Discontinuous Reception Analysis and Optimization
Lowering the power consumption is among the primary requirements for MTC applications because most of the MTC devices are powered by battery. To achieve this, discontinuous reception (DRX) is employed in LTE/LTE-A network. With DRX, a UE only turns on the receiver at some pre-defined time points while sleeps at others. However, DRX mechanism provides a power saving capability at the expense of an extra delay. Therefore it is preferred that the DRX parameters are selected such that the power saving is maximized while the application delay constraint is satisfied.
We provide two methods to analyze the detailed DRX mechanism in LTE/LTE-A. The first method deals with MTC applications with Poisson traffic. With this method, one can calculate the power saving factor and latency for a given DRX parameter set, which can be used to select the suitable DRX parameter. The second method is applicable to analyze the DRX performance with sporadic traffic. Based on this method, we also provide a simple method to find the optimal DRX parameter which maximizes the power saving factor while maintaining the latency requirement. The result was published in.
• Zhou, Kaijie; Nikaein, Navid; Spyropoulos, Thrasyvoulos, » LTE/LTE-A discontinuous reception modeling for machine type communications », IEEE Wireless Communications Letters, vol.2, no.1, pp.102-105, 2013. and will be submitted as one part of.
• Zhou, Kaijie; Nikaein, Navid; Spyropoulos, Thrasyvoulos, « DRX modeling and optimization for sporadic machine type communications », under preparation. In addition to the above contributions which comprise this thesis, some work on traffic modeling for MTC is carried out.
• Navid Nikaein, Markus Laner, Kaijie Zhou, Philipp Svoboda, Dejan Drajic, Milica Popovic, Srdjan Krco, « Simple traffic modeling framework for MTC », 10th International Symposium on Wireless Communication Systems (ISWCS), 27-30 August 2013, Ilmenau, Germany.
Machine Type Communications
Machine type communication MTC (or Machine to Machine (M2M) communications) is seen as a form of data communication that does not necessarily require human interaction . In parallel to the evolving of mobile communication systems, the application of machine type communications (MTC) has been growing very fast as well, for example: remote monitoring/ control, intelligent transport system (ITS), e-health, fleet-tracing, smart grid, etc. One of the real deployment is ekobus , where the public vehicles are used to monitor environmental parameters and to provide traffic information. It is predicted the MTC promises huge market growth with expected 50 billion connected devices by 2020 . However, different from the conventional human-to-human (H2H) communications, such as voice or web surfing, MTC has some specific characteristics and requirements, which requires significant improvements in the wireless communication system.
MTC is a very active area under discussion in 3GPP for integration within the LTE/LTE-A framework and more generally within European Telecommunications Standardization Institute (ETSI) M2M adhoc group. It would not be surprising to find more and more work related to the constraints imposed by M2M in 3GPP RAN groups in the coming years. MTC poses many interesting problems with respect to traffic modeling and the related PHY/MAC procedures (HARQ, adaptive coding and modulation, MAC layer scheduling, etc.). Another key aspect is the design of low -layer signaling which allows for extremely short acquisition times for event -driven traffic and switching between idle, sleep, and active states. In this section, we provide a brief introduction to MTC. We introduce the network architecture, applications, and benefits of MTC and then discuss the challenges of MTC and the efforts to address these challenges.
Network Architecture for Machine Type Communications
Fig. 2.11  demonstrates the M2M network architecture proposed by ETSI, which includes the device and gateway domain as well as network domain. The device and gateway domain includes the following components :
• M2M device: a device which runs M2M applications by the use of M2M service.
• M2M area network: connects M2M device and M2M Gateway. Usually personal area network (PAN) is used as M2M Area network such as: Zigbee, Bluetooth, IEEE 802.15, etc.
• M2M Gateway: a gateway acts as a proxy between M2M devices and Network domain; it collects and transmits information from M2M device.
The network domain consist of the following elements :
• Access network: provides communications between core networks and m2M device and gateway domain.
Table of contents :
List of Abbreviations
List of Figures
List of Tables
1.3 Organization of the Thesis
2.2 Machine Type Communications
3 Random Access Optimization
3.2 Random Access in LTE
3.3 Packet Aggregation for Machine Type Communications with Random Access
3.4 TTI Bundling for Machine Type Communications with Random Access
3.5 Usage of the Proposed Methods
4 Contention Based Access
4.2 Contention Based Access
4.3 Implementation of Contention Based Access in LTE
4.4 Resource Allocation Scheme for Contention Based Access
4.5 Simulation Results
4.6 Application Scenario for Contention Based Access
5 Discontinuous Reception Modeling and Optimization
5.2 DRX Mechanism in LTE
5.3 DRX Modeling for Poisson Distributed Traffic
5.4 DRX Modeling and Optimization for Sporadic Traffic
6 Conclusion and Future Work
6.2 Future Work
A Abstract for thesis in French
A.2 Optimisation de l’accès alé atoire
A.3 Accès basé Contention
A.4 La modélisation de la réception discontinue et l’optimisation