A first repeater obtains a second set of MT baseband signals, with each baseband signal in the second set corresponding to one of the MT transmission antennas, and MT being a positive integer. The first repeater divides the MT transmission antennas into groups, with each group containing a predetermined number of antennas not exceeding NR, and NR being the number of reception antennas at a UE and a positive integer. The first repeater allocates a first subset of L second transmission time intervals associated with a second SCS to the groups of transmission antennas, with the L second transmission time intervals corresponding to a first transmission time interval associated with a first SCS. The first repeater transmits RF signals on a second carrier frequency and carrying a subset of the second set of MT baseband signals, in each interval of the first subset of the L second transmission time intervals.