US Patent 11464045 Random access

An apparatus is configured to transmit at least one first random access request by using a first preamble to a first handover target cell or to a first beam provided by a serving cell. If the first random access request is responded, the apparatus carries out a synchronization to the first handover target cell or to the first beam provided by the serving cell. If the first random access request is not responded, the apparatus transmits at least one second random access request by using at least one second preamble to at least one second handover target cell or to at least one second beam provided by the serving cell. The apparatus stores information on not-responded first or second random access requests or resources not used for random access requests, wherein the information comprises preambles used. The apparatus transmits, after being synchronized, the stored information to either the first handover target cell, the at least one second handover target cell or the serving cell for being used in random access resource allocation.