The present disclosure provides a method and a device in a communication node used for wireless communications. A communication node first receives first information and second information; and then transmits a first radio signal; and monitors a first signaling in a first time window; the first information is used to determine a time length of the first time window, an interval between an end for a transmission of the first radio signal and a start of the first time window is a first time interval, and the second information is used to determine a time length of the first time interval; a bit output by a first bit block through channel coding is used to generate the first radio signal, the first bit block carries a first identity, and a second identity is used for monitoring the first signaling. The present disclosure helps improve the performance of random access.