A first wireless device receives, from a base station, configuration parameters of a scheduling request for a sidelink buffer status report (BSR) of a sidelink between the first wireless device and a second wireless device. The scheduling request is triggered for the sidelink BSR in response to data becoming available for transmission to the second wireless device via the sidelink. The first wireless transmits, based on the triggering and to the base station, a preamble for a random access procedure to obtain a first uplink grant to transmit the sidelink B SR. The sidelink BSR is transmitted via a second uplink grant different from the first uplink grant indicated in a random access response corresponding to the preamble. The random access procedure is stopped in response to transmitting the sidelink BSR.