Random access process of an unlicensed cell in a wireless device

Abstract

A wireless device receives a message indicating a maximum counter value. A listen-before-talk (LBT) is performed for transmission of a preamble for a random access (RA) procedure. When a corresponding RA response is not received: a preamble transmission opportunity counter is increased based on the LBT being performed; a preamble transmission counter is increased based on the LBT being successful; the RA procedure is considered unsuccessfully completed in response to the preamble transmission counter reaching the maximum counter value; and the RA procedure is considered unsuccessfully completed in response to the preamble transmission opportunity counter reaching the maximum counter value.

Dependencies are inferred from the claim text.