I would like to know, for scheduling purposes, how long should it take to design a transceiver. Does the duration depend on frequency? How should I determine how long it should take?
Now depends. Is about an RFIC transceiver or a discrete components transceiver?
Other factors that set the complexity of a transceiver design are: communication type (full-duplex, half-duplex, semi-duplex), frequency range, modulation (digital modulation or analog modulation), modulation bandwidth, receiver sensitivity, transmitter output power, PLL phase noise, etc.