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Underground Communications

London Underground is the oldest underground tube that exists in the world and it is used by millions of Londoners. However, it has one major fault compared to any other metropolitan cities' underground networks. It doesn't have a cellular network so the Londoners, who use the tube stations, will experience a few inconveniences. The UK government recently announced that the mobile coverage for London underground should be installed before the 2012 London Olympic. And the installation has been postponed several times because of economic costs and suppliers' unwillingness. Therefore, our group wanted to research about any possible technologies which we can employed in order to install a mobile coverage for London underground.

There are three main systems that we have found out: wireless underground sensor network (WUSN) using electricalmagnetic (EM) waves or using magnetic induction (MI) system or using leaky coaxial cable. EM waves system, mainly microwave, uses several antennas to transmit and receive the signal, but it has three main faults in underground environment: the high path loss, the dynamic channel condition and the large antenna size. Unlike EM waves system, MI system uses a coil of wire for reception and transmission of the signal. Furthermore, it can resolve the problems faced by EM system. Be aware before using both systems because both of their transmission ranges are less than 10 metres. It thus makes them inefficient to apply in real world. Nowadays there is not any technical improvement made to solve this problem so for now the leaky coaxial cable is the best system for us.

 

Video Interview

We interviewed a few people to get their opinion on whether implementing underground communications is feasible or not. The video can be found below.

 

 

 

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