A method comprising: determining a time division duplex "TDD" group by a base station in a mobile communication network, wherein the TDD group contains multiple TDD UL-DL configurations, referred to as TDD configurations, and wherein each configuration indicates which subframe is an uplink "UL" subframe, a downlink "DL" subframe, and a special subframe, respectively; broadcasting a TDD configuration selected from the TDD group, referred to as TDD reference configuration, to a first UE via a system information block "SIB", and wherein the first UE is a legacy UE that does not support dynamic TDD adaptation and wherein a legacy UE is a UE released before LTE Release 12; transmitting a TDD configuration selected from the TDD group, referred to as instantaneous TDD configuration, to a second UE, wherein the second UE is a new-released UE that supports dynamic TDD adaptation and wherein a new-released UE is a UE released in or after LTE Release 12; scheduling downlink "DL" data transmission in a DL subframe for legacy UE whereby a corresponding hybrid automatic repeat request "HARQ" feedback for the DL data transmission is transmitted in a common UL subframe of the TDD group; and/or allocating an UL grant for legacy UE in a DL subframe for UL data transmission whereby UL data is transmitted in a common UL subframe of the TDD group; and/or scheduling UL data transmission in a UL subframe for legacy UE whereby a corresponding hybrid automatic repeat request "HARQ" feedback for the UL data transmission is transmitted in a common DL subframe of the TDD group, characterized in that the multiple TDD UL-DL configurations in the TDD group are determined prior to selecting the TDD reference configuration from the TDD group. determining a time division duplex "TDD" group by a base station in a mobile communication network, wherein the TDD group contains multiple TDD UL-DL configurations, referred to as TDD configurations, and wherein each configuration indicates which subframe is an uplink "UL" subframe, a downlink "DL" subframe, and a special subframe, respectively; broadcasting a TDD configuration selected from the TDD group, referred to as TDD reference configuration, to a first UE via a system information block "SIB", and wherein the first UE is a legacy UE that does not support dynamic TDD adaptation and wherein a legacy UE is a UE released before LTE Release 12; transmitting a TDD configuration selected from the TDD group, referred to as instantaneous TDD configuration, to a second UE, wherein the second UE is a new-released UE that supports dynamic TDD adaptation and wherein a new-released UE is a UE released in or after LTE Release 12; scheduling downlink "DL" data transmission in a DL subframe for legacy UE whereby a corresponding hybrid automatic repeat request "HARQ" feedback for the DL data transmission is transmitted in a common UL subframe of the TDD group; and/or allocating an UL grant for legacy UE in a DL subframe for UL data transmission whereby UL data is transmitted in a common UL subframe of the TDD group; and/or scheduling UL data transmission in a UL subframe for legacy UE whereby a corresponding hybrid automatic repeat request "HARQ" feedback for the UL data transmission is transmitted in a common DL subframe of the TDD group, characterized in that the multiple TDD UL-DL configurations in the TDD group are determined prior to selecting the TDD reference configuration from the TDD group.