A device may use sidelink request and sidelink response (e.g., DSS/STS and DRS) resources (in a sub-band) of different sizes depending on whether the sub-band is a primary sub-band or secondary sub-band. The device may transmit more information in the request/response resources of a primary sub-band than in the request/response resources of a secondary sub-band. The device may transmit small amounts of information in its request/response resources in secondary sub-bands. The resources in the secondary sub-bands may include, for example, reference signals, and signals indicating occupation of the sub-band. The device may utilize tone signaling for request/response signaling in the secondary sub-bands (at least because the amount of information being conveyed in the secondary sub-bands is small) and digital signaling in the primary sub-band (at least because the amount of information being conveyed in the primary sub-band is large in comparison to that being conveyed in the secondary sub-bands).