The growing demand for multimedia services over wireless networks requires significant enhancements to the user’s entertainment experience. In the digital home where multimedia content is wirelessly distributed across different devices and locations (Figure 1) the problem of providing reliable audio/video services is becoming very important now.

In spite of the fact that the modern technology offers attractive wireless solutions with the throughput performance of up to 108 Mbps, the existing wireless networks do not meet the special needs of digital audio/video streaming. Distribution of multimedia content in wireless environment may encounter a number of problems. For example, a user watching wirelessly streamed video on his laptop may constantly experience video quality degradation with occasional picture distortions and breakups if one of the following takes place:

• the user runs several applications simultaneously (e.g. video session and ftp download)
• there are other users on the network who run their applications
• a microwave oven is in use in the kitchen
• a person walks in the way of the network’s radio waves (“human traffic”)
• the user moves around with a laptop

The acceptable video quality for these very simple scenarios can not be guaranteed with the widely available WLAN products today. The problem is that the wireless channel is not stable. Due to interference and mobility, the available bandwidth and error rates are highly variable. This project is related to the new mechanisms that are needed to be deployed in the network to provide a certain level of quality (Quality of Service) for multimedia applications.

The research subjects under this project deal with various QoS mechanisms at different levels spanning over physical, data link, network and application layers.

• Jochen Miroll