A guard period for switching between uplink and downlink subframes is created by shortening an uplink subframe, i.e., by not transmitting during one or more symbol intervals at the beginning of the subframe interval. A grant message includes signaling indicating when a shortened subframe should be transmitted. An example method is implemented in a first wireless node configured to transmit data in transmit subframes occurring at defined subframe intervals and having a predetermined number of symbol intervals. This example method includes determining (1620) that a transmit subframe is to be shortened, relative to the predetermined number of symbol intervals and, in response to this determination, shortening (1630) transmission of the transmit subframe by not transmitting during a beginning portion of the subframe interval for the transmit subframe and transmitting during the remainder of the subframe interval.