Network-assisted fallback to contention-based random access

An apparatus of a terminal connected to at least one network slice and being subject to a handover from a source access point to a target access point, the apparatus comprising

• at least one processor,
• at least one memory including computer program code, and
• at least one interface configured for communication with at least another apparatus,
• the at least one processor, with the at least one memory and the computer program code, being configured to cause the apparatus to perform:
• receiving a handover command message including a specification of random access channel resources to be used by said terminal for contention-free random access during a handover processing and handover assistance information indicative of a first pool of random access channel resources of a plurality of pools of random access channel resources to be used for contention-based random access processing, said first pool of random access channel resources being to be used by said terminal upon fallback to contention-based random access during said handover processing, and
• utilizing said first pool of random access channel resources upon fallback to contention-based random access during said handover processing.

An apparatus of a target access point being a target of a handover of a terminal connected to at least one network slice from a source access point, the apparatus comprising

• at least one processor,
• at least one memory including computer program code, and
• at least one interface configured for communication with at least another apparatus,
• the at least one processor, with the at least one memory and the computer program code, being configured to cause the apparatus to perform:
• receiving a handover request including information on said at least one network slice,
• selecting, from a plurality of pools of random access channel resources to be used for contention-based random access processing, a first pool of random access channel resources to be used by said terminal upon fallback to contention-based random access during a handover processing, wherein said selecting is based on at least one of network slice related information on terminals in radio resource control idle mode, on terminals in radio resource control inactive mode, and/or on terminals in radio resource control connected mode, and of available random access channel resources, and
• transmitting a handover request acknowledgement message including handover assistance information indicative of said first pool of random access channel resources.

An apparatus of a source access point being a source of a handover of a terminal connected to at least one network slice from said source access point to a target access point, the apparatus comprising

• at least one processor,
• at least one memory including computer program code, and
• at least one interface configured for communication with at least another apparatus,
• the at least one processor, with the at least one memory and the computer program code, being configured to cause the apparatus to perform:
• transmitting a handover request including information on said at least one network slice,
• receiving a handover request acknowledgement message including handover assistance information indicative of a first pool of random access channel resources of a plurality of pools of random access channel resources to be used for contention-based random access processing, said first pool of random access channel resources being to be used by said terminal upon fallback to contention-based random access during a handover processing, and
• transmitting a handover command message including a specification of random access channel resources to be used by said terminal for contention-free random access during a handover processing and said handover assistance information indicative of said first pool of random access channel resources.