A user equipment, comprising: a receiver operative to receive a first group of Downlink Control Information, DCIs, and a second group of DCIs from a base station; and a circuitry operative to blindly detect the first group of DCIs, comprising DCI3_SL and DCI4_SL, wherein the first group of DCIs are DCIs for scheduling sidelink, SL, transmission between the user equipment and another user equipment, and the second group of DCIs comprising DCI1_uu and DCI2_uu, wherein the second group of DCIs are DCIs for scheduling transmission between the user equipment and the base station, wherein the size relation of said four DCIs is expressed as DCI1_uu > DCI4_SL > DCI2_uu > DCI3_SL, so as to perform transmission and/or reception based on a rule which is known by the base station and the user equipment beforehand, wherein said rule indicates that before being received by the user equipment, the first group of DCIs and the second group of DCIs have been subject to size alignment, comprising: aligning, for each DCI of the first group of DCIs, one of the size of the DCI of the first group and the size of a selected DCI of the second group of DCIs with the other based on said rule, if the size of the DCI of the first group is different from the size of each DCI of the second group of DCIs, wherein the selected DCI of the second group is a DCI whose size is closest to the size of the DCI of the first group among DCIs of the second group having sizes larger than the size of the DCI of the first group. a receiver operative to receive a first group of Downlink Control Information, DCIs, and a second group of DCIs from a base station; and a circuitry operative to blindly detect the first group of DCIs, comprising DCI3_SL and DCI4_SL, wherein the first group of DCIs are DCIs for scheduling sidelink, SL, transmission between the user equipment and another user equipment, and the second group of DCIs comprising DCI1_uu and DCI2_uu, wherein the second group of DCIs are DCIs for scheduling transmission between the user equipment and the base station, wherein the size relation of said four DCIs is expressed as DCI1_uu > DCI4_SL > DCI2_uu > DCI3_SL, so as to perform transmission and/or reception based on a rule which is known by the base station and the user equipment beforehand, wherein said rule indicates that before being received by the user equipment, the first group of DCIs and the second group of DCIs have been subject to size alignment, comprising: aligning, for each DCI of the first group of DCIs, one of the size of the DCI of the first group and the size of a selected DCI of the second group of DCIs with the other based on said rule, if the size of the DCI of the first group is different from the size of each DCI of the second group of DCIs, wherein the selected DCI of the second group is a DCI whose size is closest to the size of the DCI of the first group among DCIs of the second group having sizes larger than the size of the DCI of the first group. the first group of DCIs are DCIs for scheduling sidelink, SL, transmission between the user equipment and another user equipment, and the second group of DCIs comprising DCI1_uu and DCI2_uu, wherein the second group of DCIs are DCIs for scheduling transmission between the user equipment and the base station, wherein the size relation of said four DCIs is expressed as DCI1_uu > DCI4_SL > DCI2_uu > DCI3_SL, so as to perform transmission and/or reception based on a rule which is known by the base station and the user equipment beforehand, wherein said rule indicates that before being received by the user equipment, the first group of DCIs and the second group of DCIs have been subject to size alignment, comprising: aligning, for each DCI of the first group of DCIs, one of the size of the DCI of the first group and the size of a selected DCI of the second group of DCIs with the other based on said rule, if the size of the DCI of the first group is different from the size of each DCI of the second group of DCIs, wherein the selected DCI of the second group is a DCI whose size is closest to the size of the DCI of the first group among DCIs of the second group having sizes larger than the size of the DCI of the first group. the second group of DCIs are DCIs for scheduling transmission between the user equipment and the base station, wherein the size relation of said four DCIs is expressed as DCI1_uu > DCI4_SL > DCI2_uu > DCI3_SL, so as to perform transmission and/or reception based on a rule which is known by the base station and the user equipment beforehand, wherein said rule indicates that before being received by the user equipment, the first group of DCIs and the second group of DCIs have been subject to size alignment, comprising: aligning, for each DCI of the first group of DCIs, one of the size of the DCI of the first group and the size of a selected DCI of the second group of DCIs with the other based on said rule, if the size of the DCI of the first group is different from the size of each DCI of the second group of DCIs, wherein the selected DCI of the second group is a DCI whose size is closest to the size of the DCI of the first group among DCIs of the second group having sizes larger than the size of the DCI of the first group.