Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may receive, from a second UE on a sidelink channel, an indicator of a state of the sidelink channel. Accordingly, the first UE may transmit, to a base station, a request for an additional resource for the sidelink channel, based at least in part on determining that the indicator of the state of the sidelink channel satisfies a condition. For example, the first UE may determine that a modulation and coding scheme (MCS) supported by a current resource for the sidelink channel is outside a range of MCSs granted by the base station. In some aspects, the request may include a negative-acknowledgement (NACK) signal, and the first UE may also transmit a scheduling request for transmitting the indicator of the state of the sidelink channel Numerous other aspects are provided.