Asynchronous Connectionless Research Articles

Low Power Multi-Hop Networking Analysis in Intelligent Environments.

Intelligent systems are driven by the latest technological advances in many different areas such as sensing, embedded systems, wireless communications or context recognition. This paper focuses on some of those areas. Concretely, the paper deals with wireless communications issues in embedded systems. More precisely, the paper combines the multi-hop networking with Bluetooth technology and a quality of service (QoS) metric, the latency. Bluetooth is a radio license-free worldwide communication standard that makes low power multi-hop wireless networking available. It establishes piconets (point-to-point and point-to-multipoint links) and scatternets (multi-hop networks). As a result, many Bluetooth nodes can be interconnected to set up ambient intelligent networks. Then, this paper presents the results of the investigation on multi-hop latency with park and sniff Bluetooth low power modes conducted over the hardware test bench previously implemented. In addition, the empirical models to estimate the latency of multi-hop communications over Bluetooth Asynchronous Connectionless Links (ACL) in park and sniff mode are given. The designers of devices and networks for intelligent systems will benefit from the estimation of the latency in Bluetooth multi-hop communications that the models provide.

Performance analysis of Bluetooth asynchronous connection-less service

In recent years Bluetooth has been a growing technology for ad-hoc wireless communication between embedded devices, in a range of 10 m. Such a network is called a piconet, in which a master employs round-robin mechanism to poll and serve the slaves. Many new products have become Bluetooth enabled recently, which may cause a complex mix of traffic. Two types of connection are being offered in this network: the Synchronous Connection-Oriented (SCO), and the Asynchronous Connection-Less (ACL). ACL is proper for best-effort service as in IP networks, which has gained more importance as now a day’s most of the applications have moved to IP, and may carry bursty traffic. In this paper, to analyze the Bluetooth ACL, a general model for complex mix of traffic, which is the superposition of many ON–OFF mini-sources, is considered. Moreover, due to unreliable nature of wireless media, a Channel Failure Rate (CFR) has been assumed. This system has been investigated analytically and its performance has been evaluated. The effects of channel failure and packet size on the mean delay and waiting time have been studied by simulations as well.

INTERFERENCE OF 802.11B WLAN AND BLUETOOTH: ANALYSIS AND PERFORMANCE EVALUATION

IEEE 802.11 and Bluetooth, these two operating in the unlicensed 2.4 GHz frequency band are becoming more and more popular in the mobile computing world. The number of devices equipped with IEEE 802.11 and Bluetooth is growing drastically. Result is the number of co-located devices, say within 10 meters, grown to a limit, so that it may causes interference issues in the 2.4 GHz radio frequency spectrum. Bluetooth supports both voice synchronous connection oriented (SCO) data and asynchronous connection less (ACL) packets. In this paper, we investigate the interference issues of 2.4 GHz frequency band. In addition, this paper presents a new Bluetooth voice packet Synchronous Connection Oriented with Repeated Transmission (SCORT) scheme to optimize the performance of 2.4 GHz frequency band by minimizing the interference between Bluetooth and 802.11 wireless networks. For the sake of experimental verifications, we provide a comprehensive simulation results using Matlab Simulink.

Neuro-Fuzzy Control for MPEG Video Transmission Over Bluetooth

The application of a neuro-fuzzy (NF) controller to moving picture expert group (MPEG-2) video transmission over a Bluetooth asynchronous connectionless (ACL) is presented in this paper. MPEG variable bit rate (VBR) data sources experience unpredictability, long delay, and excessive loss, due to sudden variations in bit rate. Therefore, it is practically impossible to transmit MPEG-2 VBR video sources over a Bluetooth channel with a limited transmission speed and considerable wireless interferences without loss of data or image quality degradation. In this work, a traffic-shaping buffer is introduced before the host controller interface (HCI) of the Bluetooth protocol stack to obstruct excessive MPEG VBR data sources during the peak transmission periods. An integrated neuro-fuzzy controller monitors and reduces the burstiness of the traffic-shaper output rate to facilitate the MPEG VBR video sources to conform to the token-bucket contract before entering the Bluetooth channel. A conventional rule-based-fuzzy (RBF) controller oversees the arrival rate to the traffic-shaper to avoid saturation or starvation of the buffer. The computer simulation results demonstrate that applications of the NF and RBF schemes reduce excessive delay and data loss at the HCI as compared with conventional video transmission in Bluetooth ACL links

유비쿼터스 지능형 공간에서의 로봇 에이전트 설계 및 응용

This paper presents a robotic agent design and application in the ubiquitous intelligent space. We set up an experimental environment with Bluetooth host, Bluetooth client, furniture and home appliance, and robotic agents. First, the agents basically performed patrol guard to detect unexpected penetration, and to keep home safely from gas-leakage, electric leakage, and so on. They were out to patrol fur a robbery while navigating in a living room and a private room. In this task, we used an area-based action making and a hexagon-based Q-learning to control the agents. Second, the agents communicate with Bluetooth host device to access and control a home appliance. The Bluetooth host offers a manual control to person by inquiring a client robot when one would like to check some place especially. In this exercise, we organize asynchronous connection less (ACL) between the host and the client robots and control the robot maneuver by Bluetooth host controller interface (HCI).