Time and frequency alignment is critical for ensuring QoS for application such as voice, real-time video, wireless hand-off, and data over a converged access medium. To satisfy the accuracy of time synchronization, both adjusting Communication path asymmetry and ratio of frequency between the time-aware systems are important. Network Time Protocol (NTP) is not satisfies time-sensitive applications. IEEE 1588 Precision Time Protocol (PTP) and IEEE 802.1AS don' t calculate the communication path asymmetry. We propose the Single-TimeSync frame for reducing the number of control frames, adjusting propagation delay asymmetry and ratio of frequency originated with slave time-aware station clock. We simulate with base model in OPNET.

An efficient method for transmitting the robot control data over wireless Internet based on UDP protocol is proposed. The method allocates the highest priority to the robot control data and transmits them multiply from the base station. Simulation results show that very low packet delay and low packet errors can be achieved by the proposed method.

Time and frequency alignment is critical for ensuring QoS for applications such as voice, real-time video, wireless hand-off, and data over a converged access medium. To satisfy the accuracy of time synchronization, propagation delay measurement is required between time-sensitive devices. There is existing network technology for time synchronization, such as network time protocol (NTP), IEEE 1588 precision time protocol (PTP), and IEEE 802.1AS. NTP, however, is not suitable for synchronization in time-sensitive applications. IEEE 1588 PTP and IEEE 802.1AS have problems where there are too many messages in LAN. We propose a single frame format and a method of propagation delay measurement using a single frame in bridged LANs. The experiment results show that the proposed method reduces time variation from NTP and control messages about 47% from IEEE 802.1AS.

Today, A matter of concern of home network technology increase. The standard of communication between home network devices are required. IEEE 802.1 AVB(Audio/Video Bridging) specifies transmission method for time-sensitive data between these devices using Ethernet in bridged local area networks. IEEE 802.1 AVB and IEEE 1588 PTP(Precision Time Protocol) have various message type for grandmaster selection and synchronize the devices. These messages bring on complexity protocol. We propose a method that uses Single TimeSync frame in order to the problem. Our proposal is appropriate process complexity and low transmission delay for home network by using the TimeSync frame. Furthermore, after all devices are adjusted to the single TimeSync frame, a resource reservation, a forwarding and queueing rule are needed for a time-sensitive application.

With the growth of digital media devices, researchers are developing techniques for transmission of real-time trafficover the network. Above all, network techniques that utilize Ethernet are in the limelight because of the advantages of Ethernet. A standardized network technique for isochronous traffic over Ethernet is in progress in IEEE 802.1 Audio/Video Bridge Task Group (AVB TG). This paper proposes a network technique for real-time traffic over an Ethernet model, that is, a AVB model with a synchronization method between devices. This paper proposes time synchronization and resource reservation for transmission of real-time traffic in synchronized devices. In this paper, we implement a AVB model through OPNET, and analyze the efficiency of the proposed methods.

Improving the performance of delay-constrained video streaming over wireless networks is one of the most important issues for various multimedia-related applications, as well as for the efficient overall utilization of the wireless medium. In this paper, we propose a scheme for adaptive admission control and scheduling for frame-based multimedia traffic in the 802.11 wireless local area networks. The conventional scheduler used for IEEE 802.11e is not suitable for VBR traffic such as MPEG-4 because only a single fixed TXOP is allocated from the hybrid Coordinator. In our scheme, we divide an MPEG flow into three different classes of video-frames depending on the user-QoS, and Our scheme is distributed admission control for each divided videoframe types and poll scheduling adaptive admission control for the flow.

By growth of digital media devices, a number of researches are in progress for transmission of isochronous traffic over network. Above all, network techniques that apply Ethernet, are in the limelight because of advantages of Ethernet. A standardization of network technique for isochronous traffic over Ethernet is in progress in IEEE 802.1 AVB TG. This paper proposed network technique for isochronous traffic over Ethernet model, that is, synchronous Ethernet model with synchronization method between devices. And this paper proposed bandwidth reservation method for transmission of isochronous traffic in synchronized devices. In this paper, synchronous Ethernet model is implemented through OPNET, efficiency of proposed methods is analyzed.