1. A method of wireless communications, comprising:determining a number of relevant synchronization signal blocks (SSBs) with respect to a communication based on one or more of: a maximum number of SSBs for a frequency band of the communication, a state of a user equipment (UE), or whether the SSBs are for a serving cell or neighbor cell;
determining a compressed index length based on the number of relevant SSBs;
transmitting or receiving the communication including a compressed index value indicating a single SSB, the compressed index value having the compressed index length; and
mapping between the compressed index value and an SSB index value for the single SSB based on the compressed index length and the number of relevant SSBs, wherein determining the number of relevant SSBs comprises determining a subset of the maximum number of SSBs that are configured for a base station based on an indication from the base station, and the compressed index length is zero when a single SSB is configured.