Cheolhyo Lee

A study on proposed IEEE 802.15 WBAN MAC protocols

Sensor networks are being researched and deployed in wide range of applications in healthcare. These networks when centered on the proximity of human body create an unique structure. The IEEE 802.15 Task Group 6 (TG6), Body Area Networks (BAN) or Wireless BAN (WBAN) is formed to address specific needs of this area. The task group is developing a communication standard optimized for low power devices and operation in, on or around the human body. The purpose is to serve a variety of applications including medical, and non-medical such as consumer electronics/personal entertainment and others. It is still in developing stage and implementation of the standard is not finalized yet. Various institutes/groups have proposed MAC protocols specifically to address the needs of WBAN. In this paper we present an analysis of these protocols. We compared and analyzed each protocol on fifteen diverse points starting from BAN requirements to energy efficiency.

Physical layer designs for WBAN systems in IEEE 802.15.6 proposals

This paper presents the trend of physical layer designs for WBAN systems in IEEE 802.15.6 proposals. According to the technical requirement of the WBAN task group, many companies and research institutes have proposed physical layer architectures to provide fundamental technologies for the WBAN communication systems. Since there are various service scenarios for in-body or on-body applications, the physical layer proposals include UWB as well as narrowband techniques. Hence we summarize the design issues for the physical layer proposals with the category of narrowband and UWB signals. The key features of the proposals are described with the frequency bands, modulations, and other technical aspects.

An enhanced MAC protocol of IEEE 802.15.4 for wireless body area networks

As the demand for personalized service increases, many researchers are interested in the wireless body area network (WBAN) including in-body and on-body communications. This paper provides an enhanced MAC framework based on IEEE 802.15.4 which may be one of the promising technologies for WBAN. The proposed scheme covers the functions of polling access, emergency transmission, and 2-hop network extension considering in-body and on-body communication environments. Also we set up test environment to operate the proposed MAC scheme.

Numerical Analysis of CSMA/CA for Pattern-Based WBAN System

This paper presents a numerical analysis of a CSMA/CA mechanism for a pattern-based WBAN system. Several equations are derived to observe the number of back-off periods required by high, medium, and low traffic BAN Nodes (BNs). Numerical results show that CSMA/CA mechanism is not suitable for medium and low traffic BNs, and high traffic BNs encounter heavy collision problems. This suggests the use of a TDMA-based solution that can solve a range of problems including traffic heterogeneity and correlation problems.

Performance of a one-way ranging method for WBAN healthcare services

Localization is an important factor to enhance availability of healthcare monitoring systems for the patient and asset tracking. This paper provides an efficient ranging measurement technique of OWR method based on the impulse radio UWB for the WBAN healthcare services. When fixed reference nodes broadcast the ranging messages in a network, the mobile nodes measure the time of arrived messages and retrieve the time information written by the reference nodes. For the performance evaluation, the ranging and positioning error are investigated using the proposed method.

Multi-metric geo-routing protocol for tactical ad hoc networks

Tactical ad hoc networks equipped with multiple radios have been considered as the basis of future force communication networks envisioned for use in the network-centric warfare paradigm. In this paper, we propose a new geographical routing protocol for such a multi-radio, multi-band tactical ad hoc networking environment. Our protocol is designed to use more than a single routing metric with multiple radio interfaces, each of which runs on different frequency bands. The idea behind the proposed scheme is to choose the right metric and radio for QoS provisioning. Simulation results using the well-known OPNET simulator confirm that the proposed scheme can enhance the routing performance in terms of efficiency and QoS requirement in tactical ad hoc networks.

UWB communication and networking systems with chaotic oscillator for low rate WPAN

This paper focused on the chaotic UWB (ultrawide band) systems for low rate WPAN. According to the UWB signal generation methods, there are three types of signals such as impulse, chaos, and chirp suggested by IEEE WPAN TG4a. The chaotic UWB signal generation has advantage of arbitrary wide band pulse shape. Based on chaotic signal, chaotic UWB communication systems are implemented, which is composed of RF blocks and digital blocks. And then they are interconnected as star topology with coordinator and several end nodes and shown the functions of image transferring

A 3D object measurement method using a single view camera

For the inspection of 3D objects, machine vision systems require information on the height and size resolution of the 3D object. Most camera calibration methods use a stereo-camera system or two cameras with laser, which is expensive and involves difficult configuration related to specific variables, such as the power and position of laser and the position of camera. To overcome these problems, a new calibration method is proposed for inspecting 3D objects using a single camera. 3D spatial resolution information is obtained from the images using a new 3D calibration frame. The accuracy of the proposed method is compared with ground truth data for a 3D donut-shape component and a test component manufactured by a CNC machine. The maximum errors for the 3D donut-shape and the test component were less than 0.5 mm and 1 mm, respectively.

MAC hardware platform for on-body WBAN applications

This paper shows the design of MAC hardware platform based on IEEE 802.15.6 for on-body WBAN applications. Considering beacon mode with sperframe boundaries, several types of access functions are implemented such as random access and scheduled accesses. And high resolution timers and status control logics are embedded in the FPGA devices for the operation of Tx and Rx control, protocol control, and several interfaces.

The Implementation of the IEEE 802.15.4a MAC and Location Application System for Low Rate WPAN

The ranging functions for the low rate WPAN have been one of the attractive issues to provide diverse applications. The IEEE 802.15.4a Task Group has specified alternative PHY and partially modified MAC using UWB signals to support more precise ranging accuracy. Based on the standard PHY and MAC of IEEE, this paper describes the implementation of the IEEE 802.15.4a MAC and for ranging and data communication functions. Also we suggest the location application system implemented with the indoor positioning algorithm and data processing functions, as well as data acquisition procedure from the end devices in the WPAN1.