A method for configuring an interlace structure in a wideband system, performed by a user equipment, LTE, wherein the wideband system comprises a bandwidth part, BWP, containing a plurality of subbands ( N; SB0, SB1), each subband, SB, being formed by resource blocks, RB, characterized in that the method comprises the steps of: - obtaining, for each SB within the BWP, at least two structure indications related to two structure parameters out of the three following structure parameters: ∘ a starting subband RB, SS-RB, defined as the first RB of a subband; ∘ a guardband, GB, defined as one or several consecutive RBs starting from the SS-RB; and ∘ a starting always-valid RB, AV-RB, defined as the first RB after the guardband ends; - obtaining a subcarrier spacing indication related to a subcarrier spacing, wherein the subcarrier spacing defines a pre-defined number of RBs forming an interlace and an interlace spacing between two RBs with a same interlace index; - obtaining at least one interlace index indication related to one location of an RB of interlace index i-th, i being either pre-defined or indicated with the location; and - configuring the interlace structure by: ∘ determining all interlaces within the BWP based on the at least one interlace index indication and the subcarrier spacing indication; and, for each SB, based on the at least two structure indications, by: ∘ determining a set of AV-RBs starting from the starting AV-RB and containing a number of consecutive RBs corresponding to the pre-defined number of RBs forming an interlace; and ∘ determining a set of potential-valid RBs, PV-RB, as all RBs other than the determined AV-RBs; so that based on the configured interlace structure, the UE determines an allocated frequency resource to transmit a physical uplink channel in a wireless communication system supporting an unlicensed band. - obtaining, for each SB within the BWP, at least two structure indications related to two structure parameters out of the three following structure parameters: ∘ a starting subband RB, SS-RB, defined as the first RB of a subband; ∘ a guardband, GB, defined as one or several consecutive RBs starting from the SS-RB; and ∘ a starting always-valid RB, AV-RB, defined as the first RB after the guardband ends; ∘ a starting subband RB, SS-RB, defined as the first RB of a subband; ∘ a guardband, GB, defined as one or several consecutive RBs starting from the SS-RB; and ∘ a starting always-valid RB, AV-RB, defined as the first RB after the guardband ends; - obtaining a subcarrier spacing indication related to a subcarrier spacing, wherein the subcarrier spacing defines a pre-defined number of RBs forming an interlace and an interlace spacing between two RBs with a same interlace index; - obtaining at least one interlace index indication related to one location of an RB of interlace index i-th, i being either pre-defined or indicated with the location; and - configuring the interlace structure by: ∘ determining all interlaces within the BWP based on the at least one interlace index indication and the subcarrier spacing indication; and, for each SB, based on the at least two structure indications, by: ∘ determining a set of AV-RBs starting from the starting AV-RB and containing a number of consecutive RBs corresponding to the pre-defined number of RBs forming an interlace; and ∘ determining a set of potential-valid RBs, PV-RB, as all RBs other than the determined AV-RBs; so that based on the configured interlace structure, the UE determines an allocated frequency resource to transmit a physical uplink channel in a wireless communication system supporting an unlicensed band. ∘ determining all interlaces within the BWP based on the at least one interlace index indication and the subcarrier spacing indication; ∘ determining a set of AV-RBs starting from the starting AV-RB and containing a number of consecutive RBs corresponding to the pre-defined number of RBs forming an interlace; and ∘ determining a set of potential-valid RBs, PV-RB, as all RBs other than the determined AV-RBs;