A method for transmitting and/or receiving wireless data and an apparatus therefor are provided. The method includes the steps of (a) when the length of a collection of data in an application layer is longer than the length of the payload of a protocol which the lower layer supports, dividing the collection of data into a plurality of protocol units, and transmitting the protocol units of data after adding at least one of the length information and location information of the data divided into the protocol units; and (b) determining whether or not a loss of data occurred, by referring to the information on the length and location of data divided into the protocol units in the step (a), and inserting blank data into the part corresponding to the lost data to re-form the entire collection of data.

Apparatus for transmitting/receiving wireless data and method thereof

We examine the rationale for and systems aspects of using layered coding for the transmission of images and video over heterogeneous communication networks. We advocate multi-resolution layered coding (MLC) and present architectural alternatives that can support it within the scope of existing standards and technologies. Since the premise of layered coding is controlled loss, the issues of error control and concealment are central. We demonstrate that MLC exhibits good error tolerance, effectively compensating for errors in situations where traditional error concealment schemes, based on the interpolation of pixels in adjacent blocks, are ineffective. In particular, MLC yields a higher peak signal-to-noise ratio (PSNR) than two-layer coding when packet loss occurs in the base layer. Finally, we show that MLC can effectively exploit efficient network error control strategies which distribute redundancy non-uniformly and provide unequal levels of protection across layers.

Multi-resolution Layered Coding for Real-Time Image Transmission

Kompressionsverfahren für Video und Audio

When a system is teleoperated in the indoor environment through the wireless LAN, the communication time delay that is due to the inherent characteristic and surrounding environment is random and unbounded. The time delay has a significant effect on the stability and performance of the teleoperating system. In this paper, we present the method that is the image compression to reduce the time delay, measuring time delay, and switching control-mode corresponding to time delay automatically, to improve stability and performance. The simple experiment is conducted to demonstrate the feasibility.

The Mobile Robot Teleoperation to Consider the Time–Delay of Wireless Network

Video streaming over wireless networks has undergone enormous development recently due to the continuing growth in wireless communication, especially since the emergence of 3G wireless networks. The new generations of wireless networks pose many challenges, including supporting quality of service over wireless communication links. This is due to the time-varying characteristics of wireless channel. Therefore, a more flexible and efficient bandwidth allocation scheme is needed. This paper is a part of ongoing work to come up with a more robust scheme that is capable of rapidly adapting to changes in network conditions. The proposed scheme focuses on the wireless part of the network, providing high quality video service and better network resource utilization.

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Video Delivery over Broadband Mobile Networks

Hierarchical coding of images and continuous media can be used to effectively control congestion in high-speed networks supporting interactive multimedia communications. However, the tradeoffs of the use of hierarchical coding have not yet been adequately investigated. We have undertaken an empirical study to investigate the effectiveness of hierarchical coding through the hierarchical mode of JPEG from a network perspective. A static analysis of hierarchical JPEG images in comparison to baseline JPEG images in terms of QoS management by packet discarding is provided. We also share our experiences in the implementation of hierarchical JPEG.

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J.K. Han

Papers

Networking applications of the hierarchical mode of the JPEG standard