M2M Terminals Research Articles

Sharing It My Way: Efficient M2M Access in LTE/LTE-A Networks

When a large number of machine-to-machine (M2M) terminals attempt to access the Long-Term Evolution (LTE)/LTE Advanced (LTE-A) cellular network using the physical random access channel (PRACH), congestion and overload may result, which can lead to serious degradation of performance for both M2M and human-to-human (H2H) terminals. The main cause for this is the inherent complexity of the four-way handshake used for random access, which is well suited for H2H terminal access but unsuitable for massive M2M access. In this paper, we describe an efficient scheme for concurrent M2M and H2H access on the PRACH, which separates the resources for M2M and H2H access at the level of preamble codes and avoids the use of the four-step handshake for M2M terminals by implementing a carrier sense multiple access with collision avoidance (CSMA/CA) overlay network using the designated preamble codes. We analyze the performance of the scheme for both H2H and M2M traffic and show the values of the most important design parameters that enable this scheme to support concurrent access by H2H and M2M terminals with little performance degradation.

Coverage enhancement techniques for machine-to-machine communications over LTE

The tremendous growth of machine-tomachine (M2M) applications has been a great attractor to cellular network operators to provide machine-type communication services. One of the important challenges for cellular systems supporting M2M terminals is coverage, because terminals can be located in spaces in buildings and structures suffering from significant penetration losses. Since these terminals are also often stationary, they are permanently without cellular coverage. To address this critical issue, the third generation partnership project (3GPP), and in particular its radio access network technical specification group, commenced work on coverage enhancement (CE) for long-term evolution (LTE) systems in June 2013. This article reviews the CE objectives defined for LTE machine-type communication and presents CE methods for LTE downlink and uplink channels discussed in this group. The presented methods achieve CE in a spectrally efficient manner and without notably affecting performance for legacy (non- M2M) devices.

QoE preserving resource scheduling for M2M terminals and human users in LTE networks

We study in this paper the impact of supporting a large number of machine to machine M2M communication terminals in the 4th generation 4G long term evolution LTE wireless networks. Our main focus in the study is on how to accommodate the large number of M2M devices without negatively impacting the human subscribers' quality of experience QoE. We propose dividing the available radio resources between human users and M2M devices such that human users' QoE is preserved. Our proposal adds new M2M-specific quality of service QoS class indicators QCIs for classifying M2M traffic bearers. We use the new classes in a new priority-based scheduler to allocate radio resources to preserve human users' QoE and fairly fulfil M2M terminals' communication requests.

Practical aspects of cellular M2M systems design

This paper highlights some crucial design challenges of Machine-to-Machine (M2M) systems. The focus is on the cellular based, wireless wide area network systems. Design of M2M terminals, used as wireless sensor nodes, is covered in detail, including the criteria for selecting appropriate core and hard- ware peripherals. Discussion is extended to modeling and design of terminal?s embedded software. Communication using framework and backend application software architectures are explored. Practical examples of the described design principles are demonstrated.

Medium access control techniques in M2M communication: survey and critical review

AbstractMachine‐to‐machine (M2M) communication has received increasing attention in recent year. An M2M network exhibits some salient features such as large number of machines/devices, low data rates, delay tolerant/sensitive, small packets, energy constrained and low or no mobility. A large number of M2M terminals may exist in a small area with many trying to simultaneously and randomly access for channel resources, which will result in overload and access problem. This increased signalling overhead and diverse requirements of machine‐type communication (MTC) devices call for the development of flexible and efficient scheduling and random access techniques. In an M2M scenario, where the network is operating at high offered load with a large number of contending transmitters, distributed random access techniques are more appropriate than centralised scheduling techniques because of less control messages and better channel utilisation. There is a need for comparison of various medium access methods that can be used in the development of an efficient hybrid M2M and human to human network. In this article, we review and compare various scheduling and random access techniques in cellular networks, particularly in Long‐Term Evolution. We also discuss how successful they are to fulfill the unique requirements of M2M communication and networking. Resource management in M2M networks with a large number of MTC devices is also discussed from the access point of view. Energy efficiency, being one of the main challenges of quality‐of‐service‐constrained M2M communication, is also discussed. Minimisation of the energy consumption is tightly bound to channel access and hence considered in the comparison of various medium access control protocols. Finally, some potential research directions related to access control and resource allocation are presented for future work. Copyright © 2014 John Wiley & Sons, Ltd.

M2M 단말간 직접통신을 위한 PHY 프레임구조 설계

본 논문에서는 셀룰라시스템이 운용중인 Licensed 주파수 대역에서 M2M 단말간 직접통신을 공존운용하기 위한 PHY 프레임구조를 제안한다. 최근 들어 SmartGrid, Mobile Health, Smart Car를 포함한 M2M(Machine to Machine) 서비스 시장이 빠른 속도로 성장하고 있다. 이러한 M2M 서비스를 Licensed 주파수 대역 기반의 셀룰라시스템을 통해서 제공하는 경우 자원의 낭비를 초래할 수 있다. 일예로, 서로 인접하여 위치하는 시나리오에서는 M2M 단말간 직접통신을 하는 것이 자원 활용 측면에서 효율적이다. 본 논문에서는 기존 셀룰라 통신시스템의 PHY 프레임구조를 변경하지 않는 것을 중요한 요구사항으로 정한다. 이러한 하위호환성 요구사항을 만족시키면서, 기존 셀룰라시스템과 동일한 licensed 주파수 대역에서 공존운용이 가능한 M2M 단말간 직접통신시스템의 PHY 프레임구조를 제안한다. 따라서, 본 논문에서 제안하는 M2M 직접통신을 위한 프레임 구조는 기존 셀룰라시스템과의 호환성을 유지하면서, M2M 단말간 직접통신을 위한 추가적인 주파수 소요 없이 한정된 주파수 자원을 효율적으로 활용할 수 있는 방안이 되리라 예상된다.

Proposal of Data-Centric Network for Mobile and Dynamic Machine-to-Machine Communication

Machine-to-Machine (M2M) communication is expected to grow in networks of the future, where massive numbers of low cost, low function M2M terminals communicate in many-to-many manner in an extremely mobile and dynamic environment. We propose a network architecture called Data-centric Network (DCN) where communication is done using a data identifier (ID) and the dynamic data registered by mobile terminals can be retrieved by specifying the data ID. DCN mitigates the problems of prior arts, which are large size of routing table and transaction load of name resolution service. DCN introduces concept of route attraction and aggregation in which the related routes are attracted to an aggregation point and aggregated to reduce routing table size, and route optimization in which optimized routes are established routes to reduce access transaction load to the aggregation points. These allow the proposed architecture to deal with ever increasing number of data and terminals with frequent mobility and changes in data.

Machine-to-Machine Communications and Security Solution in Cellular Systems

This paper introduces an efficient machine-to-machine (M2M) communication model based on 4G cellular systems. M2M terminals are capable of establishing Ad Hoc clusters wherever they are close enough. It is also possible to extend the cellular coverage for M2M terminals through multi-hop Ad Hoc connections. The M2M terminal structure is proposed accordingly to meet the mass production and security requirements. The security becomes more critical in Ad Hoc mode as new nodes attach to the cluster. A simplified protocol stack is considered here, while key components are introduced to provide secure communications between M2M and the network and also amongst M2M terminals.