"FMeXtra: Another On-Channel Solution"

"Eventually DRE asked the NRSC to reactivate the DAB subcommittee.
Early on, we saw that IBOC was going nowhere as long as there were
multiple proponents, and even in the best estimates, it would be many
years before there would be any return on investment. So we decided to
license our patent portfolio for use in IBOC to USA Digital Radio,
which eventually merged with Lucent’s IBOC group to form Ibiquity. We
are an Ibiquity shareholder... There is no significant difference in
spectrum occupancy between the 'extended hybrid' mode of IBOC today
and these earlier systems, which were deemed by the NRSC and others to
be incompatible with the host analog FM signal."

http://www.bext.com/RW/RWFMeXtraDec05.pdf