Carrier configuring and signalling scheduling in co-existing radio access systems

A method for operating a radio access system comprises configuring a first carrier and a second carrier for use for radio access in a first radio access system. The second carrier is configured for frequency division duplex signalling. A useful frequency band of the second carrier is defined to, at least partially, overlap in frequency with a useful frequency band of a third carrier of a second radio access system. At least a part of the useful frequency band of the second carrier overlaps in frequency with guard bands of the third carrier. A method for signal scheduling comprises scheduling, in a first radio access system having a first carrier with a first carrier frequency band and a second carrier with a second carrier frequency band, uplink signals in the second carrier. Network nodes for carrying out the methods are also presented.