 Overview
Broadband mobile wireless communication services
are becoming widespread, such as IEEE802.11b
wireless LAN access services or third-generation
mobile communications services based on WCDMA
technology. This project is working on the
core technologies for Quality of Service
(QoS) control to provide high quality multimedia
streaming over broadband wireless channels.
3G and future wireless networks
 Research items
Wireless channels have unique features compared
to wired channels. Reception conditions such
as bandwidth, delay, and the distribution
of packet losses, are affected by user movements
and changes in the surrounding environment.
Therefore it is necessary to adapt the multimedia
streaming to changes of the wireless channel
conditions, minimizing the influences of
the changes on the quality of the streams
users receive.
We have established a framework specifying
functional module construction, interfaces,
and protocols for the QoS control of complete
systems required in mobile communications
environments, in order to continually provide
smooth streaming distribution services. This
technology has the following features:
We are exploring several techniques to offer
better QoS for streaming over a wireless
network.
 Publications
- Yamanouchi et al., ``Buffer control for multimedia
stream transfer over WCDMA packet mode with
ARQ,'' (in Japanese) IPSJ SIG-DPS, May 2001.
- Yasuki et al., ``A Framework of QoS control
for Mobile Streaming Services,'' (in Japanese)
Proc. of DICOMO2001, June 2001.
- Kushida et al., ``A Framework for mobile
wireless multimedia QoS,'' (in Japanese)
Proc. of DICOMO2001, June 2001.
- Onoe et al., ``Mobility Extensions for a
Multimedia Session Management Protocol,''
(in Japanese) IPSJ SIG-MBL, September 2001.
- Murao et al., ``A Video Streaming System
for Wireless Network,'' (in Japanese) IPSJ SIG-DPS, September 2001.
- Taniguchi et al., ``Bandwidth estimation
and multimedia contents transfer control
in a wireless network environment,'' (in
Japanese) IPSJ SIG-DPS, November 2001.
- Hagino et al., ``File Change Method for Mobile
Streaming QoS Server,'' (in Japanese) IPSJ SIG-MBL, March 2002.
- Komaki et al., ``A QoS Control for Wireless
Streaming with Intermediary Network Information,''
(in Japanese) IPSJ SIG-MBL, March 2002.
 Related information
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