A method and apparatus for cross link (XL) establishment are disclosed. In the method and apparatus, a XL between a terminal wireless transmit/receive unit (T-WTRU) and a helper WTRU (H-WTRU) is established. The T-WTRU and the H-WTRU may be configured to operate in a plurality of RRC states and a plurality of RRC substates. To establish the XL, neighbor discovery, association information exchange, and a H-WTRU selection may be performed. Radio resource control (RRC) configuration of the T-WTRU and the H-WTRU may also be performed. In the method and apparatus, coverage for a T-WTRU may be handed over between a network and a H-WTRU or between two H-WTRUs.