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Wireless communications offers its own particular set of problems. More specifically, wireless networks are characterized by the frequent occurrence of transmission errors along with a low bandwidth. Hence, they put strong constraints on the transmission of digital images. Since JPEG2000 provides high compression efficiency, it is a good candidate for wireless multimedia applications. Moreover, due to its high scalability, JPEG2000 enables a wide range of Quality of Service (QoS) strategies for network operators.

To be widely adopted for wireless multimedia applications, JPEG 2000 has to be robust to transmission errors. To address this issue, the JPEG committee has established a new work item, JPEG 2000 Wireless (JPWL), as Part 11 of the standard. Its purpose is to standardise tools and methods to achieve the efficient transmission of JPEG 2000 imagery over an error-prone wireless network.

The main functionality of the JPWL system is to protect the codestream against transmission errors. More precisely, the protection technique modifies the codestream to make it more resilient to errors, e.g. by adding redundancy or interleaving the data. The decoding process detects the occurrence of errors and corrects them whenever possible.  

A second functionality is to describe the degree of sensitivity of different parts of the codestream to transmission errors. This information can subsequently be used for unequal error protection. More specifically, sensitive parts of the codestream can be more heavily protected than less sensitive parts.

A third functionality is to describe the locations of residual errors in the codestream. This information can subsequently be used to make a decoder aware of the information loss and to prevent decoding corrupted parts of the stream.

Using the technologies standardised in JPWL, JPEG2000 becomes very resilient to transmission errors. Therefore, JPEG2000 is an ideal candidate for the efficient transmission of digital images and video in wireless applications. Indeed, recent studies have shown that Motion JPEG2000 is very well suited for video transmission over wireless channels. Specifically, it has been shown that Motion JPEG2000 outperforms the state-of-the-art MPEG-4 in terms of coding efficiency, error resilience, complexity, scalability and coding delay.

While the proposed solutions are not tuned to a specific network protocol, particular attention has been paid to three important use cases: 3^rd generation wireless phone networks (3GPP/3GPP2), WLAN (IEEE 802.11 family of standards) and Digital Radio Mondiale (DRM).

Among potential killer applications for JPWL, Multimedia Messaging Service (MMS) knows a very rapid growth and is widely seen has one of the only bright spot in the wireless telecom industry. Other potential applications include video streaming and video conferencing.
For further information, please contact:

Didier Nicholson, THALES Communications, chair of JPWL Ad hoc group.
or
Frederic Dufaux, EPFL, co-chair of JPWL Ad hoc group.