Wireless advances boost mobile mulitimedia communications
A wide range of innovations being made at Southampton University’s Department of Electronics and Computer Science is enabling wireless telephone networks to be extended to carry high-quality video, speech, handwriting and graphics for advanced multimedia applications.
The work, by Southampton’s Mobile Multimedia Communications Team (MMCT) in Professor Raymond Steele’s Communications Group efficiently exploits available wireless ‘bandwidths’ to deliver robust, high-quality multimedia communications to anyone, at any location. The bandwidth of a communications link determines the amount of digital ‘bits’ of information it can carry. Speech conversations of acceptable quality can be encoded at rates as low as 5600 bits per second (bps), but moving-image video typically needs significantly higher transmission speeds.
How the Digital Assistant may look Multimedia communications can be handled reliably and efficiently using optical fibres, cables and other high-speed ‘broadband’ networks, which are relatively free from external interference. Users of wireless communications, however, move through a variety of environments, such as a tunnel, which are hostile to the propagation of radio waves. Maintaining consistent mobile reception quality therefore requires complex signal processing.
The MMCT has developed a range of bandwidth-efficient transmission methods for delivering multimedia services, including new encoder/decoder (codec) techniques. These translate video, speech and other signals into ‘compressed’ digital codes that need fewer bps during transmission, with the signal retranslated into the original format by the decoder. Codecs are implemented as micro-chips in users’ devices.
The MMCT’s innovations, many of which were made on EPSRC-funded projects, are targeted towards optimising the overall performance of wireless networks by creating systems that automatically adapt and reconfigure themselves to maintain optimum performance levels, for instance by programmable codecs. This ensures the ever-changing demands of mobile users are met in the most efficient way.
Such overall system optimisation is the team’s prime contribution to making feasible the ubiquitous use of ‘multimode’ devices which combine the capabilities of a mobile phone, hand-held ‘palmtop’ computer, radio receiver, videophone and electronic handwriting tablet. Much industrial interest has been shown in this work.
The MMCT has also been collaborating with academic/industrial consortia on the EU-funded FIRST programme developing a reconfigurable multimedia terminal and MEDIAN project for creating high-speed local wireless networks within buildings.