DAB radio was originally sold as the natural successor to AM and FM radio in the UK, providing better audio quality, easier tuning and extra station information. It's been a mixed bag though, with patchy coverage and many radio stations broadcasting in low bit-rates. The problem partly lies in the UK's infrastructure -- the existing transmitters and data streams lack the capacity to offer so many stations at a higher audio quality. The first commercial, national "multiplex" for DAB radio is already full and while a second is in the works, Ofcom wants to explore how service can be improved at the local level. It goes beyond the UK government's promise to part-fund new transmitters by 2016.