The present disclosure provides a method and a device in a UE and a base station used for wireless communication. A first node operates first information; and transmits a first radio signal in M1 out of M frequency sub-band(s). Herein, the first information is used for determining S candidate integers; K1 of K bit block group(s) is(are) used for generating the first radio signal, any of the K bit block group(s) comprises a positive integer number of code block(s); K is a candidate integer of the S1 candidate integer(s), M is used for determining the S1 candidate integer(s) out of the S candidate integers; the first node is a base station, the operating action is transmitting; or the first node is a UE, the operating action is receiving. The above method helps reduce the amount of data retransmitted due to LBT failure of partial frequency sub-bands.