US-12621736-B2 - Methods and apparatuses for radio communication

US12621736B2US 12621736 B2US12621736 B2US 12621736B2US-12621736-B2

Abstract

A method for radio communication. The method includes: receiving at least one conditional handover execution condition for conducting a conditional handover; determining at least one future QoS that characterizes a quality of at least one radio channel between a radio terminal and a radio access node for at least one future time instant; and evaluating the at least one handover condition based at least on the at least one future QoS.

Inventors

Khaled Shawky HASSAN
Maximilian STARK

Assignees

ROBERT BOSCH GMBH

Dates

Publication Date: 20260505
Application Date: 20230403

Claims (14)

1 . A method comprising: receiving at least one handover condition for conducting a handover; determining at least one future QoS that characterizes a quality of at least one radio channel between a radio terminal and a radio access node for at least one future time instant; evaluating the at least one handover condition based at least on the at least one future QoS; and transmitting a reevaluation request when the at least one evaluated handover condition indicates an unfavorable future handover situation.
2 . The method according to claim 1 , further comprising: transmitting, when the at least one evaluated handover condition indicates an expected future handover from a serving cell to at least one candidate cell, a pre-trigger indication that indicates at least a probability of the expected future handover.
3 . The method according to claim 1 , further comprising: receiving, as a response to the transmitted reevaluation request, at least one further handover condition for conducting a handover; determining at least one further future QoS for at least one further future time instant; evaluating the at least one further handover condition based at least on the at least one further future QoS; and transmitting, when the at least one evaluated further handover condition indicates an expected future handover from a serving cell to at least one candidate cell, a pre-trigger indication.
4 . The method according to claim 1 , further comprising: receiving, as a response to the transmitted reevaluation request, at least one cancel message that indicates to cancel a present handover; and maintaining a connection to the serving cell upon reception of the cancel message.
5 . The method according to claim 1 , further comprising: evaluating the at least one handover condition based at least on at least one present QoS; detaching, upon the at least one handover condition being met, from the serving cell; and synchronizing, upon the at least one handover condition being met, to a target cell associated with the at least one handover condition that is met.
6 . The method according to claim 1 , wherein the determining of the at least one future QoS includes: determining the at least one future QoS associated with the serving cell, using at least one machine-trained model, wherein at least one present QoS that characterizes a quality of the at least one radio channel between the radio terminal and the serving radio access node for at least one present time instant and at least one motion information that characterizes a relative motion of the radio terminal to the serving radio access node is provided as an input of the at least one machine trained model, and wherein the at least one future QoS associated with the serving cell is provided as an output of the at least one machine trained model.
7 . The method according to claim 1 , wherein the determining of the at least one future QoS includes: determining the at least one future QoS associated with a candidate cell, using at least one machine-trained model, wherein at least one present QoS of the candidate cell that characterizes a quality of the at least one radio channel between the radio terminal and a candidate radio access node for at least one present time instant and at least one motion information that characterizes a relative motion of the radio terminal to the candidate radio access node is provided as an input of the at least one machine trained model, and wherein the at least one future QoS associated with the candidate cell is provided as an output of the at least one machine trained model.
8 . An apparatus, comprising: a receiver configured to receive at least one handover condition for conducting a handover; a determining device configured to determine at least one future QoS that characterizes a quality of at least one radio channel between a radio terminal and a radio access node for at least one future time instant; an evaluator configured to evaluate the at least one handover condition based at least on the at least one future QoS; and a transmitter configured to transmit a reevaluation request when the at least one evaluated handover condition indicates an unfavorable future handover situation.
9 . A method comprising: determining at least one handover condition for conducting a handover associated with a radio terminal; transmitting the at least one handover condition; receiving a pre-trigger indication that indicates a probability of an expected future handover that is associated with the at least one transmitted handover condition; re-scheduling, based on the received pre-trigger indication, radio resources; and transmitting a scheduling grant based on the re-scheduled radio resources.
10 . The method according to claim 9 , further comprising: transmitting, based on the received pre-trigger indication, a preparation message to at least one primary candidate radio access node indicating that the radio terminal will probably initiate the handover with the primary candidate radio access node.
11 . The method according to claim 9 , further comprising: transmitting, based on the received pre-trigger indication, a cancel message to at least one secondary candidate radio access node indicating a cancellation of a present potential handover associated with the radio terminal and the secondary candidate radio access node.
12 . A method comprising: determining at least one handover condition for conducting a handover associated with a radio terminal; transmitting the at least one handover condition; receiving a pre-trigger indication that indicates a probability of an expected future handover that is associated with the at least one transmitted handover condition; determining, upon reception of a reevaluation request, at least one further handover condition for conducting a conditional handover associated with the radio terminal; and transmitting the at least one further handover condition.
13 . A method comprising: determining at least one handover condition for conducting a handover associated with a radio terminal; transmitting the at least one handover condition; receiving a pre-trigger indication that indicates a probability of an expected future handover that is associated with the at least one transmitted handover condition; determining, upon reception of a reevaluation request, that the handover procedure associated with the radio terminal will be cancelled; and transmitting at least one cancel message.
14 . An apparatus, comprising: a determination device configured to determine at least one handover condition for conducting a handover associated with a radio terminal; a transmitter configured to transmit the at least one handover condition; a receiver configured to receive a pre-trigger indication that indicates a probability of an expected future handover that is associated with the at least one transmitted conditional handover condition; and a further transmitter configured to transmit a scheduling grant determined from a re-scheduling of radio resources based on the received pre-trigger indication.

Description

BACKGROUND INFORMATION There are provided advances in radio communication, in particular in cellular handover technology. In general, the QoS of a radio channel can be modeled in a stochastic manner. In turn, one can also describe analytically how specific channel characteristics vary over time and space. Nevertheless, the stochastic channel models cannot capture reality precisely which would only be possible using so-called ray tracing in simulations. Thus, the periodic monitoring of the channel is required to assess the channels. SUMMARY An aspect of the present invention is directed to the following subject matter: A method comprising receiving at least one conditional handover execution condition for conducting a conditional handover; determining at least one future QoS that characterizes a quality of at least one radio channel between a radio terminal and a radio access node for at least one future time instant; and evaluating the at least one handover condition based at least on the at least one future QoS. Advantageously, receiving the conditional handover execution condition allows a centrally managed handover actions. By injecting a predicted future QoS into the handover condition, the radio terminal is able to determine a future state of the handover situation. This forecast of QoS contributes to a reduction of actual handover actions and therefore provides means for reducing service interruptions and reduces management overhead on the side of the radio access network. An advantageous example embodiment of the present invention includes transmitting, if the evaluated at least one handover condition indicates an expected future conditional handover from a serving cell to at least one candidate cell, a pre-trigger indication that indicates at least a probability of the expected future conditional handover. A legacy handover, i.e., a handover specified in Rel. 16 is known to cause a notable handover interruption time. Either the measurement report from the UE might not reach the BS or the handover command does not reach the UE due to channel degradation. This induces unpredicted interruption time/failure. The transmission of the pre-trigger indication enables for the centrally managed handover that the expected future perspective of the radio terminal is taken into consideration. Interruption times can be reduced. If multiple cells need to be prepared to further increase robustness and in the best-case scenario the mobile terminal accesses one of them, a set of resources would need to be reserved while the UE is monitoring the condition and does not perform the handover. The network therefore needs to carefully select the target candidate and keep the number of target candidate cells to a reasonable amount, especially in a resource-constrained scenario like in a high load. Standardization supports two approaches: early data forwarding and late data forwarding. In early data forwarding, data is forwarded during the preparation phase and the main benefit is to enable similar interruption performance as legacy, while increasing robustness. In that solution, the complexity increases with the number of target candidates and the time it takes until the handover is actually performed. Late data forwarding is a simpler alternative, when data starts to be forwarded by the serving node when the UE accesses the target cell. Both, late and early data forwarding benefit as the handover is predicted. An advantageous example embodiment of the present invention includes transmitting a reevaluation request if the at least one evaluated handover condition indicates an unfavorable future handover situation. Advantageously, the radio terminal/UE can decide that the radio access node/gNB or another central entity should reevaluate the received handover conditions. Therefore, the UE has the obligation to decide about whether the handover conditions are reasonable from its perspective. An advantageous example embodiment of the present invention includes: receiving, as a response to the transmitted reevaluation request, at least one further conditional handover execution condition for conducting a handover; determining at least one further future QoS for at least one further future time instant; evaluating the at least one further handover condition based at least on the at least one further future QoS; and transmitting, if the evaluated at least one further handover condition indicates an expected future conditional handover from a serving cell to at least one candidate cell, the pre-trigger indication. Advantageously, the reevaluation request can result in a pre-trigger if the radio access node of the radio access network adapts the conditional handover appropriately. An advantageous example embodiment of the present invention includes: receiving, as a response to the transmitted reevaluation request, at least one cancel message that indicates to cancel the present conditional handover; and maintaining a connection to the