Intae Ryoo

A hybrid Wi-Fi P2P with bluetooth low energy for optimizing smart device's communication property

Recently, due to the popularity of smart devices, a need for various types of wireless communication has been tremendously increasing and several types of radio technologies for easy and quick communication with peripherals have appeared. In order for implementing a Personal Area Network (PAN), low power ZigBee and Bluetooth technologies have been generally used. On the other hand, Wi-Fi Local Area Network (LAN) technology has many advantages in implementing a PAN as it’s chipset is integrated and it’s transmission speed is relatively higher than the others. As the size of multimedia data like photos, videos, and music files has increased, more efficient communication environment for faster connection establishment and higher data transmission speed should be supported for end users accordingly. Because Bluetooth technology has intrincic limitations like transmission speed and coverage, new technologies are expected to provide longer transmission distances and higher transmission rates. Further, if the full functionality of Wi-Fi P2P standard would be implemented for today’s smart devices, it would be possible to provide various kinds of mobile innovative services that could maximize user experience.Transmission rate of Bluetooth technology in early stages was only up to 1Mbps. Although this speed is as fast as 6-fold compared to existing techniques, Bluetooth can hardly support a satisfied level of services to transfer large amounts of data such as high quality musics and videos. Therefore, Bluetooth has been used only for specific communication services with limitations. Transmission speed of Bluetooth, however, has been significantly improved as time goes. That is, Bluetooth 2.0 released in 2004 supports maximum speed of 3Mbps, and Bluetooth 3.0 released in 2 009 supports up to 24Mbps. Bluetooth 4.0 released in 2 010 has low energy mode while maintaing 24Mbps and also supports coin cell with low power consumptioin.Wi-Fi P2P is a direct communication technology between terminals without any intermediate devices such as routers and access point (AP). Wi-Fi module is basically mounted on most of smart devices. Therefore, once Wi-Fi P2P technology is adapted to mobile terminals or mobile devices such as TV, laptop, printer, and camera, all the communication services and multimedia contents can be simply provided for these devices by using the Wi-Fi P2P.In this study, we have proposed a cross-layer system design for optimizing smart devices’ communication property by utilizing the characteristics of high-speed data transmission rate of Wi-Fi P2P and low power consumption communication of Bluetooth. We have also verified that the proposed technique outperforms the existing Bluetooth and Wi-Fi P2P in the comparison of throughput as well as transmission delay through OPNET simulations, which leads to faster user connections and provides better quality of services to end users.

Non-Contact Plant Growth Measurement Method and System Based on Ubiquitous Sensor Network Technologies

This paper proposes a non-contact plant growth measurement system using infrared sensors based on the ubiquitous sensor network (USN) technology. The proposed system measures plant growth parameters such as the stem radius of plants using real-time non-contact methods, and generates diameter, cross-sectional area and thickening form of plant stems using this measured data. Non-contact sensors have been used not to cause any damage to plants during measurement of the growth parameters. Once the growth parameters are measured, they are transmitted to a remote server using the sensor network technology and analyzed in the application program server. The analyzed data are then provided for administrators and a group of interested users. The proposed plant growth measurement system has been designed and implemented using fixed-type and rotary-type infrared sensor based measurement methods and devices. Finally, the system performance is compared and verified with the measurement data that have been obtained by practical field experiments.

The internet of everything based on energy efficient P2P transmission technology with Bluetooth low energy

This paper introduces a fundamental energy efficient hybrid P2P transmission technology for P2P networking environment as well as Internet of Everything (IoE) infrastructure. Based on the transmission characteristics of wireless communication technologies of Bluetooth and Wi-Fi, the proposed P2P transmission technique integrates them into an energy efficient hybrid transmission technology and provides the IPification for specific group, society, and the entire world. We have shown that the proposed hybrid transmission technology outperforms the existing transmission technologies in the aspects of initial connection establishment time and overall data transmission capability.

A 3-dimensional group management MAC scheme for mobile IoT devices in wireless sensor networks

We are truly entering the era of Internet of Things (IoT) in which all things are connected and can be used in a variety of ways regardless of time and place. Various types of sensor devices using advanced technology will gather data around us and deliver the information wherever we want. In this paper, we propose an energy efficient MAC scheme for IoT ecosystem environments that include mobile IoT sensor devices. The mobile sensor devices in a target IoT ecosystem gather and collect any required data while moving and transmitting the collected data to a sink node. Energy consumption of the sensor devices depends on the distance from the sink node and also affects overall lifetime of the IoT ecosystems. The proposed 3-D group management MAC (3-D GM MAC) scheme groups sensor devices based on the distance (hop) from the sink node and transmits the collected data only to the next higher group level. That is, the data is transmitted only in the direction to the sink node. In addition, the energy efficiency of the entire IoT ecosystem can be improved by transmitting data based on pre-configured buffer threshold values that are set differently for each group and consequently minimizing the energy consumption of sensor devices near the sink node. When any sensor device cannot transmit data to the next higher group level due to movement, it is newly assigned an appropriate group number and transmits data using a new route. We have shown that the proposed 3-D GM MAC scheme shows excellent behavior in the aspect of energy efficiency for the target IoT ecosystem by simulation. Therefore, the proposed scheme might be adaptable for mobile sensor devices used in various kinds of computing and networking environments such as IoT, big data, cloud computing, and fog computing.

Energy Efficient MAC Scheme for Wireless Sensor Networks with High-Dimensional Data Aggregate

This paper presents a novel and sustainable medium access control (MAC) scheme for wireless sensor network (WSN) systems that process high-dimensional aggregated data. Based on a preamble signal and buffer threshold analysis, it maximizes the energy efficiency of the wireless sensor devices which have limited energy resources. The proposed group management MAC (GM-MAC) approach not only sets the buffer threshold value of a sensor device to be reciprocal to the preamble signal but also sets a transmittable group value to each sensor device by using the preamble signal of the sink node. The primary difference between the previous and the proposed approach is that existing state-of-the-art schemes use duty cycle and sleep mode to save energy consumption of individual sensor devices, whereas the proposed scheme employs the group management MAC scheme for sensor devices to maximize the overall energy efficiency of the whole WSN systems by minimizing the energy consumption of sensor devices located near the sink node. Performance evaluations show that the proposed scheme outperforms the previous schemes in terms of active time of sensor devices, transmission delay, control overhead, and energy consumption. Therefore, the proposed scheme is suitable for sensor devices in a variety of wireless sensor networking environments with high-dimensional data aggregate.

Design and implementation of tiny-WiMAX connection manager (t-WCM) for specific purposed devices

WiMAX network services cannot generally be provided for special purpose devices such as credit card systems and surveillance systems since they are designed to operate only with WCM which should be installed on personal computer/smart card (PC/SC) with Windows platform. In this paper, we propose a design and implementation technique called tiny-WiMAX connection manager (t-WCM) for non-PC/SC WCM to provide WiMAX services to special purpose devices. The t-WCM is composed mainly of three units; WiMAX module control unit (WCU), data surveillance unit (DSU), and external device program unit (EPU). It also has TCP/IP protocol stack and RTOS kernel, and performs data transmission between external end users device and remote server system over WiMAX networks. For the performance evaluation of the proposed t-WCM, we have implemented the t-WCM and tested it under a commercial mobile WiMAX network environment. From the experimental results, the t-WCM is verified to show almost equal stability and delay performances with the legacy WCM and xDSL, and especially better than 1xEV-DO. As a result, it has a strong possibility to apply the t-WCM to many types of special purpose embedded systems, and consequently to provide various WiMAX network services to them.

A Smart Sensor Data Transmission Technique for Logistics and Intelligent Transportation Systems

When it comes to Internet of Things systems that include both a logistics system and an intelligent transportation system, a smart sensor is one of the key elements to collect useful information whenever and wherever necessary. This study proposes the Smart Sensor Node Group Management Medium Access Control Scheme designed to group smart sensor devices and collect data from them efficiently. The proposed scheme performs grouping of portable sensor devices connected to a system depending on the distance from the sink node and transmits data by setting different buffer thresholds to each group. This method reduces energy consumption of sensor devices located near the sink node and enhances the IoT system’s general energy efficiency. When a sensor device is moved and, thus, becomes unable to transmit data, it is allocated to a new group so that it can continue transmitting data to the sink node.