A data transmission method and apparatus are disclosed. The method includes: determining, by a source base station of a terminal in a handover process, first data and a radio air interface protocol sequence number of a data unit used to carry the first data, where the first data includes data that is not acknowledged by a terminal for correct reception during data transmission between the source base station and the terminal. The method further includes sending, by the source base station, the first data and the radio air interface protocol sequence number to a target base station; where the core network connected to the target base station is different from the core network connected to the source base station.

A first base station receives, from a wireless device, a measurement result of a cell of a second base station, and sends, to the wireless device and based on the measurement result, a command of a conditional handover towards the cell of the second base station. The command comprises at least one handover execution condition comprising at least one of a reference signal received power, a reference signal received quality, a first time value indicating a time offset for a decision of a handover execution, or a second time value indicating a time duration when the command of the conditional handover is valid. The first base station receives, from the wireless device and based on the wireless device determining that at least one criteria of the at least one handover execution condition is met by the cell, a handover execution notification indicating a random access procedure.

A first base station receives, from a wireless device, a measurement result of a cell of a second base station, and sends, to the wireless device and based on the measurement result, a command of a conditional handover towards the cell of the second base station. The command comprises at least one handover execution condition comprising at least one of a reference signal received power, a reference signal received quality, a first time value indicating a time offset for a decision of a handover execution, or a second time value indicating a time duration when the command of the conditional handover is valid. The first base station receives, from the wireless device and based on the wireless device determining that at least one criteria of the at least one handover execution condition is met by the cell, a handover execution notification indicating a random access procedure.

A first method (and related first apparatus) includes transmitting, in a handover request message, an indication of a first protocol version; a second method (and related second apparatus) includes receiving, in the handover request message, the indication, deciding, based on the received indication and a second protocol version, on a value of an information element included in a handover request acknowledgement message to be transmitted, the information element indicating usage of a first or second signaling scheme, and transmitting the handover request acknowledgement message including the information element; and in the first method receiving the handover request acknowledgement message including the information element; and a third method (and related third apparatus) including receiving the handover command message including the information element, and configuring according to one of the first and second signaling schemes indicated by the information element.

Conditional handover (CHO) configurations may include random access channel (RACH) configuration information (e.g., beam quality thresholds, beam quality threshold offsets, one or more beams associated with configured contention free random access (CFRA) resources, one or more beams associated with configured contention based random access (CBRA) resources, or some combination thereof). A user equipment (UE) may, upon detection that a handover condition in a CHO configuration has been satisfied, select a target cell beam for transmission of a random access request based on the RACH configuration information included in the CHO configuration. In various examples, the selected beam may correspond to a highest quality beam with a highest quality beam measurement value above the beam quality threshold, a beam with an earliest configured CFRA resource or an earliest configured CBRA resource (e.g., if a corresponding beam measurement at least falls within the beam quality threshold offset), etc.

Conditional handover (CHO) configurations may include random access channel (RACH) configuration information (e.g., beam quality thresholds, beam quality threshold offsets, one or more beams associated with configured contention free random access (CFRA) resources, one or more beams associated with configured contention based random access (CBRA) resources, or some combination thereof). A user equipment (UE) may, upon detection that a handover condition in a CHO configuration has been satisfied, select a target cell beam for transmission of a random access request based on the RACH configuration information included in the CHO configuration. In various examples, the selected beam may correspond to a highest quality beam with a highest quality beam measurement value above the beam quality threshold, a beam with an earliest configured CFRA resource or an earliest configured CBRA resource (e.g., if a corresponding beam measurement at least falls within the beam quality threshold offset), etc.

A technique for implementing an untethered access point (UAP) mesh involves enabling AP-local switching at one or more UAPs of the mesh. A system constructed according to the technique may include an untethered access point (UAP), including: a radio; a backhaul service set identifier (SSID) stored in a computer-readable medium; an anchor access point (AAP) selection engine embodied in a computer-readable medium. In operation, the AAP selection engine may use the radio to attempt to associate with the AAP if a beaconed backhaul SSID matches the stored backhaul SSID. A method according to the technique may include beaconing with a backhaul SSID, acting in concert with an upstream switch as an authenticator for a downstream station that responds to the beacon; providing limited local switching functionality for the downstream station.

A technique for implementing an untethered access point (UAP) mesh involves enabling AP-local switching at one or more UAPs of the mesh. A system constructed according to the technique may include an untethered access point (UAP), including: a radio; a backhaul service set identifier (SSID) stored in a computer-readable medium; an anchor access point (AAP) selection engine embodied in a computer-readable medium. In operation, the AAP selection engine may use the radio to attempt to associate with the AAP if a beaconed backhaul SSID matches the stored backhaul SSID. A method according to the technique may include beaconing with a backhaul SSID, acting in concert with an upstream switch as an authenticator for a downstream station that responds to the beacon; providing limited local switching functionality for the downstream station.

According to some embodiments, a network node is capable of operating as an integrated access and backhaul (IAB) node comprising a distributed unit (DU) and a mobile termination (MT). The IAB node performs a method comprising: obtaining (2012) configuration information for establishing an interface between the IAB node DU and a target IAB donor central unit (CU); and after a handover of the IAB node to the target donor, establishing (2114) the interface between the IAB node DU and the target IAB donor CU based on the obtained configuration information.

According to some embodiments, a network node is capable of operating as an integrated access and backhaul (IAB) node comprising a distributed unit (DU) and a mobile termination (MT). The IAB node performs a method comprising: obtaining (2012) configuration information for establishing an interface between the IAB node DU and a target IAB donor central unit (CU); and after a handover of the IAB node to the target donor, establishing (2114) the interface between the IAB node DU and the target IAB donor CU based on the obtained configuration information.