Sung-Min Oh

An Efficient Small Data Transmission Scheme in the 3GPP NB-IoT System

This letter proposes an efficient small data transmission scheme in the narrow band (NB)-Internet of Things (IoT) system. For the efficient use of radio resources, the proposed scheme enables devices in an idle state to transmit a small data packet without the radio resource control connection setup process. This can improve the maximum number of supportable devices in the NB-IoT system which has insufficient radio resources. Numerical results have shown that the proposed scheme can increase the maximum number of supportable devices by about 60% compared with the conventional scheme.

Resource allocation for device-to-device communications based on graph-coloring

In device-to-device (D2D) systems, neighboring D2D pairs provide unavoidable interference when a same resource is allocated to multiple D2D pairs. And, this interference acts as a major bottleneck which significantly deteriorates the link quality and prevents from achieving the spatial reuse gain. Hence, in this paper, we introduce the graph-coloring theory and propose a resource allocation algorithm for D2D systems in order to properly avoid dominant interference from neighboring D2D pairs. Throughout simulations results, we show that the proposed scheme provides fairly good performance compared to the optimal resource allocation, while drastically reducing the computational complexity, and performance gain over conventional schemes with respect to sum rate of D2D pairs. Moreover, the results on the outage probability illustrate that the proposed scheme improves the link quality compared to that of conventional schemes.

Dynamic RACH preamble allocation scheme

Machine-to-Machine (M2M) communication is used for automated data transmission and measurement between remote electronic devices. Every device that can use M2M communication will become a significant component of the Internet of Things (IoT) and Big Data. And there are many different applications of M2M communication (e.g., fleet management, smart metering, smart grid, and home/factory/city automation). Machine-Type-Communication (MTC) is a new service defined by the 3GPP to enable M2M devices to communicate with each other over LTE-Advanced cellular networks. Since the number of M2M devices can be fairly large compared to the H2H devices, current RACH procedure may cause a QoS degradation of H2H devices. In this paper, we propose a novel dynamic RACH preamble allocation scheme that can adjust the range of available RACH preamble according to network condition dynamically. The dynamic RACH preamble allocation scheme can be an efficient solution that can alleviate the overload problem.

Radio resource management for moving small-cells with proactive content cache

The moving small-cell (mSC) is one of solutions to accommodate traffic of the moving users cost-effectively. Due to cache storage in mSC, an mSC can directly send its data for its serving users without any intermediate. In the mSC network, broadcast and multicast protocols are utilized to push the cache contents from macro-cell base station to mSCs by using via wireless backhaul (BH) link. In this paper, we propose the radio resource management scheme for wireless BH link. In the proposed scheme, MBSs select one transmission mode between broadcast and multicast modes based on the popularity distribution of cache contents. By performance evaluation, we confirm that the proposed scheme can adaptively enhance the network performance.

Random access method with access time distribution scheme

Machine-to-Machine (M2M) communication, a promising technology enables ubiquitous connection between massive autonomous devices without human intervention. M2M communication is one of the core technologies supporting data exchange among sensing devices, processing devices, and actuating devices to facilitate various M2M applications (e.g., telematics, smart metering, smart grid, and home/factory/city automation). Machine Type Communication (MTC) is a new service defined by the 3GPP to enable M2M devices to communicate with each other over LTE-Advanced cellular networks. For huge numbers of MTC devices, one of the challenging issues is to provide an efficient way for multiple access in the network. In this paper, we propose a novel scheme named Access Time Distribution (ATD) that can distribute access time to reduce a random access overload. The ATD scheme can be an effective solution that can alleviate the overload problem.

CAN gateway for fast vehicle to vehicle (V2V) communication

Intelligent transport systems (ITS) use information and communication technologies to improve vehicle safety on roadways and effective traffic flow management. A vehicle communicates with other vehicles and/or infrastructures with wired/wireless communication technologies. In-vehicle networks are composed of numerous electronic control units (ECUs) according to the type of service in various domains (e.g. powertrain domain, body domain, and chassis domain). Vehicle to vehicle (V2V) messages related to vehicle safety should meet low-latency requirements. In addition, the information contained in V2V messages is associated with specific ECUs. For the interworking between the V2V communications and in-vehicle networks, we should consider a new method that responses necessary ECUs for specific V2V message. In this paper, we propose an effective controller area network (CAN) gateway method. This method uses CAN gateway searching for a network table based on the CAN frame for V2V message. Because of simple structure and method, the proposed method can be a good solution that controls the ECUs with ease. And it also can make V2V messages at high speed.

Development of system level simulator for evaluating performance of moving personalcell network

Due to the rapid growth of mobile traffic, most of the mobile network operators (MNOs) recently consider the deployment of heterogeneous network (HetNet) including small- and personal-cell. Since small- and personal-cells in HetNet distribute the mobile traffic concentrated on a few macro-cells and reuse the frequency bandwidth allocated in macro-cell, they can alleviate the traffic load of macro-cell and enhance the system capacity in overall network. However, the drawback due to the cross- and co-tier interference between various cells decreases the gain obtained by the deployment of small- and personal-cell. In this paper, we develop a system-level simulator for HetNet based on LTE-Advanced (LTE-A) system in order to carefully analyze these effects of small- and personal-cell deployment before their release. For the purpose, we consider three HetNet scenarios, macro-cell only, macro- and small-cell, and macro- and personal-cell scenarios, and adopt the cell layout for each scenario, the realistic wireless channel models, and the real time graphic user interface (GUI) to the developed simulator. Through the performance evaluation by utilizing the developed simulator, we confirm that the overall performance in HetNet is affected by the characteristics of small- and personal-cell.