In the United Kingdom, the roll-out of digital radio is proceeding since engineering test transmissions were started by the BBC in 1990 followed by a public launch in September 1995. The UK currently has the world's biggest digital radio network, with 103 transmitters, two national DAB ensembles and 48 local and regional DAB ensembles broadcasting over 250 commercial and 34 BBC radio stations across the UK. In the capital, London there are already more than 64 different digital stations available. In addition to DAB and DAB+, radio stations are also broadcast on digital television platform as well as internet radio in the UK. Between April 2007 and April 2008 the BBC trialled Digital Radio Mondiale on mediumwave and shortwave frequencies. Digital radio ensemble operators and stations need