Split synchronization signal configuration for unified synchronization channels and techniques for indicating communication block boundaries in wireless communication systems that use a unified synchronization signal configuration that may be used in different communication modes are described. The disclosed split synchronization signal configuration allows the same synchronization signal configuration to be used in different communication modes (or numerologies) that operate on different frequencies. The boundary indication techniques of embodiments allow efficient indication of the beginning of a communication block (such as a frame, subframe, or slot) relative to the beginning of a unified synchronization signal configuration.