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Radio-over-fibre brings broadband to remote areas Malaysian researchers have developed and lab-tested a simple yet high speed radio-over-fibre transmission system that promises cost effective broadband Internet service for rural areas in developing nations. Led by Dr Amin Malek Mohammadi, a team at the University of Nottingham Malaysia Campus (UNMC) is now negotiating with industry players to roll out a scaled-up trial.
TECHNOLOGY
The UNMC technology uses a new type of optical encoding, which can simultaneously convert and transmit multiple radio frequencies to optical signals, including mobile phone, 3G and Wi-Fi. It can transmit these signals on a single optical fibre link between five and 50 kilometres long, and convert them back to radio signals for users equipped with appropriate radioenabled Internet devices at the other end. In addition to handling multiple frequencies, the coding algorithm converts each user’s data stream into a unique optical feed that re-converts back to the appropriate radio frequency at the receiving end. In essence, the clever coding, called a mapping multiplexing technique, can “see” extra space on a fibre-optic cable. This enables the transmission of more bits per symbol compared with older, more limited binary coding, which can send only one bit per symbol. Mapping multiplexing thus allows more operators and users to efficiently share the optical fibre’s bandwidth without noticing slowdowns. The exact numbers of potential users depend on individual bandwidth use and other variables. The UNMC system also uses a novel embroidered radio antenna, sewn onto thin, flexible fabric or plastic patches that are less than half the size of a normal business card. The antenna design can be varied to improve performance, and many users in a single facility, each wearing their own patch, can use the antennas to connect their devices individually to a central 3G or Wi-Fi enabled modem. The researchers say their antennas have potential uses in medical and military applications, in environmental monitoring and for tracking miners. The team’s long term plans include further development of the mapping multiplexing technique, as well as research on advanced modulation and signal processing. The ultimate goal, say the researchers, is to send more information through optical fibres.
For further information contact: Dr Amin Malek Mohammadi and Dr Belle Ooi Faculty of Engineering The University of Nottingham Malaysia Campus E-mails: Amin.Malek@nottingham.edu.my, Belle.Ooi@nottingham.edu.my
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Dr Amin Malek sets up a horn-shaped antenna to conduct measurements in an anechoic chamber.