WO2022042948A1

WO2022042948A1 - Early pdcch / cg activation based on survival time

Info

Publication number: WO2022042948A1
Application number: PCT/EP2021/070252
Authority: WO
Inventors: Srinivasan Selvaganapathy; Ahmad AWADA; Jedrzej STANCZAK; Ömer BULAKCI; Muhammad NASEER-UL-ISLAM
Original assignee: Nokia Technologies Oy
Priority date: 2020-08-24
Filing date: 2021-07-20
Publication date: 2022-03-03

Abstract

An apparatus includes circuitry configured to: receive a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; select the at least one survival time preamble from a set of the at least one survival time preamble, based on a survival time headroom; compare the survival time headroom to the survival time headroom threshold; and transmit the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmit at least one preamble different from the at least one survival time preamble; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from a user equipment.

Description

EARLY PDCCH / CG ACTIVATION BASED ON SURVIVAL TIME

TECHNICAL FIELD

[ 0001 ] The examples and non-limiting embodiments relate generally to communications and, more particularly, to early PDCCH / CG activation based on survival time .

BACKGROUND

[ 0002 ] It is known to engineer communication networks based on quality of service ( QoS ) requirements .

SUMMARY

[ 0003 ] In accordance with an aspect , an apparatus includes at least one processor ; and at least one memory including computer program code ; wherein the at least one memory and the computer program code are configured to , with the at least one processor, cause the apparatus at least to : receive a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; select the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom; compare the survival time headroom to the survival time headroom threshold; and transmit the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmit at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from a user equipment .

[ 0004 ] In accordance with an aspect , an apparatus includes at least one processor ; and at least one memory including computer program code ; wherein the at least one memory and the computer program code are configured to , with the at least one processor, cause the apparatus at least to : receive a handover request comprising a survival time headroom status ; transmit an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and receive the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receive at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment .

[ 0005 ] In accordance with an aspect , an apparatus includes at least one processor ; and at least one memory including computer program code ; wherein the at least one memory and the computer program code are configured to , with the at least one processor, cause the apparatus at least to : transmit a handover request comprising a survival time headroom status ; receive an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and transmit the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

[ 0006 ] In accordance with an aspect , a method includes : receiving a handover command compri sing at least one survival time preamble respectively associated with at least one survival time headroom threshold; selecting the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom; comparing the survival time headroom to the survival time headroom threshold; and transmitting the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmitting at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from a user equipment . [ 0007 ] In accordance with an aspect , a method includes receiving a handover request comprising a survival time headroom status ; transmitting an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and receiving the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receiving at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment .

[ 0008 ] In accordance with an aspect , a method includes transmitting a handover request comprising a survival time headroom status ; receiving an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and transmitting the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete mes sage from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

[ 0009 ] In accordance with an aspect , an apparatus includes means for receiving a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; means for selecting the at least one survival time preamble from a set of the at least one survival time preamble, based on a survival time headroom; means for comparing the survival time headroom to the survival time headroom threshold; and means for, transmitting the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmitting at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from a user equipment .

[ 0010 ] In accordance with an aspect , an apparatus includes means for receiving a handover request comprising a survival time headroom status ; means for transmitting an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and means for, receiving the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receiving at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment .

[ 0011 ] In accordance with an aspect , an apparatus includes means for transmitting a handover request comprising a survival time headroom status ; means for receiving an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and means for transmitting the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

[ 0012 ] In accordance with an aspect , a non-transitory program storage device readable by a machine , tangibly embodying a program of instructions executable with the machine for performing operations is provided, the operations comprising : receiving a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; selecting the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom; comparing the survival time headroom to the survival time headroom threshold; and transmitting the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmitting at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from a user equipment .

[ 0013 ] In accordance with an aspect , a non-transitory program storage device readable by a machine , tangibly embodying a program of instructions executable with the machine for performing operations is provided, the operations comprising : receiving a handover request comprising a survival time headroom status ; transmitting an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and receiving the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receiving at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment .

[ 0014 ] In accordance with an aspect , a non-transitory program storage device readable by a machine , tangibly embodying a program of instructions executable with the machine for performing operations is provided, the operations comprising : transmitting a handover request comprising a survival time headroom status ; receiving an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and transmitting the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted . BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The foregoing aspects and other features are explained in the following description, taken in connection with the accompanying drawings, wherein:

[0016] FIG. 1 is a block diagram of one possible and nonlimiting system in which the example embodiments may be practiced .

[0017] FIG. 2 is a diagram illustrating the concept of survival time and the tolerance of packet loss within survival time requirements.

[0018] FIG. 3 is an illustration of survival time headroom including mobility interruption time during HO.

[0019] FIG. 4 is a message sequence diagram illustrating the early PDCCH transmission /early CG activation based on ST preamble.

[0020] FIG. 5 is a signaling diagram of early transmission based on ST preamble when the UE and network support a 2- step RACH procedure.

[0021] FIG. 6 is an example apparatus configured to implement early PDCCH / CG activation based on survival time, based on the examples described herein.

[0022] FIG. 7 shows an example method to implement early PDCCH / CG activation based on survival time, based on the examples described herein.

[0023] FIG. 8 shows another example method to implement early PDCCH / CG activation based on survival time, based on the examples described herein. [0024] FIG. 9 shows another example method to implement early PDCCH / CG activation based on survival time, based on the examples described herein.

[0025] FIG. 10 shows a user equipment method, based on the examples described herein.

[0026] FIG. 11 shows a target node method, based on the examples described herein.

[0027] FIG. 12 shows a source node method, based on the examples described herein.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0028] Turning to FIG. 1, this figure shows a block diagram of one possible and non-limiting example in which the examples may be practiced. A user equipment (UE) 110, radio access network (RAN) node 170, and network element (s) 190 are illustrated. In the example of FIG. 1, the user equipment (UE) 110 is in wireless communication with a wireless network 100. A UE is a wireless device that can access the wireless network 100. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver, Rx, 132 and a transmitter, Tx, 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. The one or more transceivers 130 are connected to one or more antennas 128 that may be part of or include an antenna array or other antenna configuration or antenna array configuration. The one or more memories 125 include computer program code 123. The UE 110 includes a module 140, comprising one of or both parts 140-1 and/or 140-2, which may be implemented in a number of ways. The module 140 may be implemented in hardware as module 140-1, such as being implemented as part of the one or more processors 120. The module 140-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 140 may be implemented as module 140-2, which is implemented as computer program code 123 and is executed by the one or more processors 120. For instance, the one or more memories 125 and the computer program code 123 may be configured to, with the one or more processors 120, cause the user equipment 110 to perform one or more of the operations as described herein. The UE 110 communicates with RAN node 170 via a wireless link 111.

[0029] The RAN node 170 in this example is a base station that provides access by wireless devices such as the UE 110 to the wireless network 100. The RAN node 170 may be, for example, a base station for 5G, also called New Radio (NR) . In 5G, the RAN node 170 may be a NG-RAN node, which is defined as either a gNB or an ng-eNB. A gNB is a node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface to a 5GC (such as, for example, the network element (s) 190) . The ng-eNB is a node providing E-UTRA user plane and control plane protocol terminations towards the UE, and connected via the NG interface to the 5GC. The NG-RAN node may include multiple gNBs, which may also include a central unit (CU) (gNB-CU) 196 and distributed unit(s) (DUs) (gNB-DUs) , of which DU 195 is shown. Note that the DU may include or be coupled to and control a radio unit (RU) . The gNB-CU is a logical node hosting radio resource control (RRC) , SDAP and PDCP protocols of the gNB or RRC and PDCP protocols of the en-gNB that controls the operation of one or more gNB-DUs. The gNB-CU terminates the Fl interface connected with the gNB-DU. The Fl interface is illustrated as reference 198, although reference 198 also illustrates a link between remote elements of the RAN node 170 and centralized elements of the RAN node 170, such as between the gNB-CU 196 and the gNB-DU 195. The gNB-DU 195 is a logical node hosting RLC, MAC and PHY layers of the gNB or en-gNB, and its operation is partly controlled by the gNB-CU 196. One gNB-CU 196 supports one or multiple cells. One cell is supported by only one gNB-DU. The gNB-DU 195 terminates the Fl interface 198 connected with the gNB-CU 196. Note that the DU 195 is considered to include the transceiver 160, e.g., as part of a RU, but some examples of this may have the transceiver 160 as part of a separate RU, e.g., under control of and connected to the DU 195. The RAN node 170 may also be an eNB (evolved NodeB) base station, for LTE (long term evolution) , or any other suitable base station or node.

[0030] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N/W I/F(s) ) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver, Rx, 162 and a transmitter, Tx, 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 may include the processor (s) 152, one or more memories 155, and network interfaces 161. Note that the DU 195 may also contain its own memory/memories and processor ( s ) , and/or other hardware, but these are not shown .

[0031] The RAN node 170 includes a module 150, comprising one of or both parts 150-1 and/or 150-2, which may be implemented in a number of ways. The module 150 may be implemented in hardware as module 150-1, such as being implemented as part of the one or more processors 152. The module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 150 may be implemented as module 150-2, which is implemented as computer program code 153 and is executed by the one or more processors 152. For instance, the one or more memories 155 and the computer program code 153 are configured to, with the one or more processors 152, cause the RAN node 170 to perform one or more of the operations as described herein. Note that the functionality of the module 150 may be distributed, such as being distributed between the DU 195 and the CU 196, or be implemented solely in the DU 195.

[0032] The one or more network interfaces 161 communicate over a network such as via the links 176 and 131. Two or more gNBs 170 may communicate using, e.g., link 176. The link 176 may be wired or wireless or both and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interface for other standards.

[0033] The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, wireless channels, and the like. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for gNB implementation for 5G, with the other elements of the RAN node 170 possibly being physically in a different location from the RRH/DU 195, and the one or more buses 157 could be implemented in part as, for example, fiber optic cable or other suitable network connection to connect the other elements (e.g., a central unit (CU) , gNB-CU 196) of the RAN node 170 to the RRH/DU 195. Reference 198 also indicates those suitable network link (s) .

[0034] It is noted that description herein indicates that "cells" perform functions, but it should be clear that equipment which forms the cell performs the functions. The cell makes up part of a base station. That is, there can be multiple cells per base station. For example, there could be three cells for a single carrier frequency and associated bandwidth, each cell covering one-third of a 360 degree area so that the single base station' s coverage area covers an approximate oval or circle. Furthermore, each cell can correspond to a single carrier and a base station may use multiple carriers. So if there are three 120 degree cells per carrier and two carriers, then the base station has a total of 6 cells.

[0035] The wireless network 100 may include a network element or elements 190 that may include core network functionality, and which provides connectivity via a link or links 181 with a further network, such as a telephone network and/or a data communications network (e.g., the Internet) . Such core network functionality for 5G may include access and mobility management function(s) (AMF(S) ) and/or user plane functions (UPF(s) ) and/or session management function(s) (SMF(s) ) . Such core network functionality for LTE may include MME (Mobility Management Entity) /SGW (Serving Gateway) functionality. These are merely example functions that may be supported by the network element (s) 190, and note that both 5G and LTE functions might be supported. The RAN node 170 is coupled via a link 131 to the network element 190. The link 131 may be implemented as, e.g., an NG interface for 5G, or an SI interface for LTE, or other suitable interface for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N/W I/F(s) ) 180, interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, with the one or more processors 175, cause the network element 190 to perform one or more operations.

[0036] The wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization. Network virtualization is categorized as either external, combining many networks, or parts of networks, into a virtual unit, or internal, providing network-like functionality to software containers on a single system. Note that the virtualized entities that result from the network virtualization are still implemented, at some level, using hardware such as processors 152 or 175 and memories 155 and 171, and also such virtualized entities create technical effects.

[0037] The computer readable memories 125, 155, and 171 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The computer readable memories 125, 155, and 171 may be means for performing storage functions. The processors 120, 152, and 175 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples. The processors 120, 152, and 175 may be means for performing functions, such as controlling the UE 110, RAN node 170, network element (s) 190, and other functions as described herein.

[0038] In general, the various embodiments of the user equipment 110 can include, but are not limited to, cellular telephones such as smart phones, tablets, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, tablets with wireless communication capabilities, as well as portable units or terminals that incorporate combinations of such functions.

[0039] UE 110, RAN node 170 and/or network element (s) 190 (and associated memories, computer program code and modules) may be configured to implement early PDCCH / CG activation based on survival time during mobility in a target cell, based on the examples described herein. Thus, computer program code 123, module 140-1, module 140-2, computer program code 153, module 150-1, module 150-2, and/or computer program code 173 may be configured to implement early PDCCH / CG activation based on survival time, based on the examples described herein.

[0040] Critical industrial loT (IIoT) traffic is typically defined with URLLC characteristics, requiring very high reliability of sending a packet within a strict delay budget. Nevertheless, various IIoT services can still continue the correct operation when a few packets are not correctly received. This notion is referred to as the survival time (ST) of the service.

[0041] The ST can be defined as in 3GPP TS 22.104 [refer to 3GPP TS 22.104, "Service requirements for cyber-physical control applications in vertical domains"] as: "The maximum survival time indicates the time period the communication service may not meet the application's requirement before there is a failure such that the communication service is deemed to be in an unavailable state" and "The time that an application consuming a communication service may continue without an anticipated message."

[0042] Furthermore, the ST can be inferred as the time or number of continuous packet losses or packets missing within required time budget for a given traffic flow. Beyond this limit the receiver of the traffic may, e.g., shut down the receiver operation due to safety measures. Hence, successful delivery of the packets before expiry of survival time can be taken as one main criterion or QoS requirement for the RAN network. A current 3GPP study item in SA2, see TR23.700-20 [refer to 3GPP TR 23.700-20, "Study on enhanced support of Industrial Internet of Things (IIoT) in the 5G System (5GS) ] , has introduced the issue of "Use of Survival Time for Deterministic Applications in 5GS" which studies the operation of including the ST information in the time sensitive communications assistance information (TSCAI) per QoS flow, which is provided from the 5G core network (5GC) to the RAN [refer to 3GPP TS 23.501, "System architecture for the 5G System (5GS) ] . The ST information can be obtained via the application function (AF) and can be provided to the session management function (SMF) . The ST can be utilized by the RAN to handle the QoS requirements of a service. The ST can be service dependent and can vary, e.g., in the order of 2 x transfer interval value where the transfer interval is 5 ms for the cooperative carrying use case [refer to 3GPP TS 22.104, "Service requirements for cyber-physical control applications in vertical domains"] . Accordingly, the ST may be obtained by the (radio) access network (R)AN from the core network (CN) . Nevertheless, there could be other means of obtaining the ST information, e.g., from a device or user equipment (UE) or configuration, e.g., from a management entity.

[0043] FIG. 2 illustrates the concept of survival time and the tolerance of packet loss within survival time requirements. Therein, an example packet flow is provided where the ST is equal to the 3 consecutive packet errors (which may be construed as 3 or more consecutive packet errors) . In Case A, since fewer than 3 consecutive packet errors are experienced, the service is in Up State. However, in case B, when 3 consecutive packet errors are experienced, the service enters the Down State, which may result in severe financial costs, as the production may stop .

[0044] Thus, FIG. 2 shows example cyclic traffic with the survival time equal to three consecutive packet errors. The system is considered unavailable if three or more consecutive packets are not delivered according to delay requirements. In Case A, one or two packets are not delivered according to delay requirements. In Case A, there is no service disruption since one or two errors can be tolerated. In Case B, the service is down since there are three consecutive errors. It is worth noting that in this example ST is based on consecutive packets. Nevertheless, other means for defining the ST can be utilized, e.g., in terms of absolute time.

[0045] The serving node (e.g. the gNB) can ensure the timely delivery of packets with survival time by mapping these packets to the configured grant or semi persistent scheduling (SPS) . Along with the fixed scheduling, the network can dynamically change the reliability of pending CG transmissions based on the delivery status of early transmissions. These changes can be managed by network scheduling .

[0046] When the UE is moving between nodes having traffic with survival time requirements, some additional changes are needed in the mobility procedure to minimize the interruption or to ensure that the interruption does not lead to ST expiry before handover execution.

[0047] The problem scenario is illustrated in FIG. 3. Specifically, FIG. 3 is an illustration of survival time headroom including mobility interruption time during HO. The problem addressed by the methods described herein is related to the mobility scenario where the UE 110 and network (e.g. source gNBl 170-1 and target gNB2 170-2) may only support classic handover mechanisms which have interruption starting from the handover command reception at the UE 110 until the RACH access success at the target node 170-2. In FIG. 3, the ST counter status is denoted by Y, the maximum tolerable ST is denoted by ST, ST headroom is denoted by ST-Y, and HO interruption time is denoted by X.

[0048] The source gNBl 170-1 and the target gNB2 170-2 as shown in FIG. 3 as well as in FIG. 4 and FIG. 5 may be implemented with the elements and features of the RAN node 170 of FIG. 1.

[0049] In case of classic handover there could be an impact to traffic with ST (survival time) requirements as given in the procedure below (see FIG. 3) . For classic handover scenarios, both the transmission and reception are suspended on sending a HO-command 302 to the UE 110 (part of the HO interruption time, denoted by X in FIG. 3) . The communication is resumed after the UE 110 completes the RACH access and sending a handover complete message. In case if the ST expires during this window, i.e., ST-Y < X, the handover is not beneficial for ST traffic as there is not enough survival time headroom to accommodate the delay in packet transfer during mobility interruption. [0050] Mechanisms are needed to reduce the HO interruption time and allow earlier resumption of transmission/reception with the target cell. This would especially be critical for UEs that start handover execution when the ST headroom is already lower or closer to the expected HO interruption time.

[0051] In classic handover scenarios, a contention-free random access (CERA) preamble is given to the UE to enable contention free RACH access to complete the handover execution. In this case, the communication between the UE and the target node, in either of the uplink or downlink direction, starts only after the UE sends the handover complete message using Msg3 of the RACH access procedure. Any pending packet transmission from the UE or network can happen after this step only.

[0052] RACH-less HO (defined in LTE Rel-14) can improve the mobility interruption time but requires a synchronized network (i.e. the source and target cells are frame/time slot aligned) .

[0053] The examples herein provide methods to enable early transmission of traffic having ST requirements during a RACH access procedure to avoid the ST expiry at the end of handover completion.

[0054] A method is provided where the UE decides to send a new preamble, referred to as ST preamble, if the available ST headroom (remaining time for ST expiry, see FIG. 3) is lower than a specific threshold (or higher than a specific threshold) to start immediate uplink and downlink transmissions associated with the ST traffic. An associated method is provided where the network provides one or more ST preamble ( s ) and an associated RACH configuration (which may of fer more frequent occasions in the target cell than the normal RACH resources ) for the ST preamble transmission . Another associated method i s provided where the network provides one or more thresholds for the ST headroom, which can be associated with the provided ST preambles .

[ 0055 ] A UE method is provided for starting early PDCCH monitoring and uplink transmi ssion . On sending a ST preamble , the UE starts monitoring PDCCH for its own C-RNTI rather than a RA-RNTI for receiving a PDSCH / PUSCH allocation or DCI indicating early activation of the configured grant for uplink and downlink . The PDCCH /PDSCH al so provides the timing advance value to be used for the uplink grant .

[ 0056 ] Further, a method is provided where the network may configure a fixed location from the time of preamble transmission where the UE can directly monitor using the configured grant configuration for DL to allow direct reception of PDSCH after ST preamble transmission . Yet another method is provided where the PDCCH indicates the activation of the uplink configured grant from a speci fic time of fset from the PDCCH reception .

[ 0057 ] Further, a method is provided where the UE informs of remaining ST headroom in the RRC-Reconf iguration- complete message to enable the target node to modi fy the pending configured grant according to the pending ST time . This method is needed if the ST headroom is not lower than the threshold at the time of preamble transmission but is reaching ST expiry on transmission of PUSCH . [0058] In some examples, the survival preamble can be configured with more number of repetitions to ensure higher reliability than the normal preamble.

[0059] The message sequence diagram illustrating the early PDCCH transmission / early CG activation based on an ST preamble is given in FIG. 4. Aspects of the modified handover procedure where the ST preamble is used to start early transmission at the target are given as follows.

[0060] Step 1 (item 401) : the UE 110 transmits a measurement report to the source node (source cell) 170-1.

[0061] Step 2 (item 402) : the source node (source cell) 170-1 transmits a handover request (including ST headroom status) to the target node (target cell) 170-2.

[0062] Step 3 (item 403) : the target node (target cell) 170-2 transmits a handover request ACK to the source node (source cell) 170-1, which includes a HO command including at least one additional ST preamble associated with an ST headroom threshold.

[0063] Step 4 (item 404) : the UE 110 is assigned with an 'ST preamble' in addition to the dedicated preamble for the target access. Particularly, in the example shown by FIG. 4, at 404 the UE 110 is provided with an RRC reconfiguration from the source node (source cell) 170-1. This is the HO command including the at least one additional ST preamble associated with the ST headroom threshold.

[0064] Step 5 (item 405) : the UE 110 evaluates ST headroom and picks one ST preamble among configured ST preambles. [0065] Step 6 (item 406) : the UE 110 selects between the ST preamble and a normal dedicated preamble for the target access based on the ST headroom threshold. In case if the ST headroom is good to select the normal RACH preamble for the first RACH attempt, but if there is no response from the network, the ST headroom may be reduced. In this case the UE switches to the ST preamble for retransmission. Thus, as shown by FIG. 4, at 406 the UE 110 compares the ST headroom against a configured threshold. If the ST headroom is higher than a threshold, the UE 110 sends the ST preamble corresponding to the threshold. Otherwise, the UE 110 sends an ordinary RACH preamble.

[0066] Step 7 (item 407) : the UE 110 sends the 'ST preamble' to indicate to the network a need to start early uplink and downlink transmission from RAR itself. Thus at 407, the UE 110 sends the ST Preamble to the target node (target cell) 170-2.

[0067] Step 8 (item 408) : the decision to use the ST preamble is based on the remaining ST value, i.e., the ST headroom ST-Y (see FIG. 3) . Thus at 408, based on the detected ST preamble, the target cell 170-2 might provide an additional UL grant and/or schedule DL data.

[0068] Step 9/10/11 (items 409, 410 and 411) : the network may activate DL/UL CG earlier based on the new DCI sent in PDCCH. As shown in FIG. 4, step 9 (item 409) represents a first option for early CG activation that includes items 410 and 411. At 410, the target node (target cell) 170-2 provides to the UE 110 DCI for activation of DL CG over PDCCH. At 411, the target node (target cell) 170-2 provides to the UE 110 DCI for activation of UL CG and timing advance . [0069] Step 12 (item 412) : the second option shown at step 12 (item 412) is early PDCCH monitoring performed by the system including UE 110, source node (source cell) 170- 1 and target node (target cell) 170-2.

[0070] Step 13/14 (items 413 and 414) : at 413 (step 13) , the NW (via the target node (target cell) 170-2) may assign to the UE 110 an additional uplink grant for uplink traffic or include the configured grant (CG) in the RAR. At 414 (step 14) , the NW may start scheduling downlink along with RAR itself without waiting for reception of RRC- Reconf iguration-Complete .

[0071] Step 15 (item 415) : the UE 110 sends an RRC Reconfiguration complete message to the target node (target cell) 170-2.

[0072] Step 16 (item 416) : HO completion occurs with the UE 110, the source node (source cell) 170-1 and target node (target cell) 170-2.

[0073] The early transmission based on ST preamble when the UE and network support the 2-step RACH procedure is illustrated in FIG. 5. Aspects of the modified handover procedure using the 2-step-RACH mechanism are given as follows .

[0074] Step 1 (item 501) : the UE 110 transmits a measurement report to the source node (source cell) 170-1.

[0075] Step 2 (item 502) : the source node (source cell) 170-1 transmits to the target node (target cell) 170-2 a handover request that includes ST headroom status. [0076] Step 3,4 (items 503 and 504) : A new CERA preamble which allows a larger Msg-A size is allocated in addition to the normal dedicated Msg-A preamble as the ST preamble. In particular, at 503, the target node (target cell) 170-2 transmits a handover request ACK to the source node (source cell) 170-1. The handover request ACK transmitted at 503 includes a HO command including at least one additional preamble associated with an ST headroom threshold. At 504, the source node (source cell) 170-1 transmits a RRC reconfiguration to the UE 110. The RRC reconfiguration transmitted at 504 includes the HO command including the at least one additional ST preamble associated with the ST headroom threshold.

[0077] Steps 5, 6 (items 505 and 506) : Based on the ST headroom (ST-Y) , see FIG. 3, the UE 110 may send Msg-A using a different preamble. Here, the UE 110 can include the pending uplink ST traffic information in the Msg-A itself. ST traffic also can be sent, if the Msg-A size allows. In particular, at 505 the UE 110 evaluates ST headroom. At 506, the UE 110 compares the ST headroom against a configured threshold. If the ST headroom is lower than the threshold, the UE 110 decides to send the ST preamble corresponding to the threshold. Otherwise, the UE 110 sends the ordinary RACH preamble.

[0078] Step 7 (item 507) : Msg-A also includes ST-headroom in this case for further decision on the target side uplink grant. In particular, at 507 the UE 110 transmits the ST preamble and Msg-A containing ST headroom information.

[0079] Step 8 (item 508) : the target node (target cell) 170-2, based on the detected ST preamble, allocates a larger payload for the next uplink grant. [0080] Step 9 (item 509) : item 509 is early PDCCH transmission based on Msg-A reception allocating more RUSCH for uplink ST traffic transmission along with RRC- Reconf iguration-Complete . In particular, at 509 the target node (target cell) 170-2 allocates PDCCH a larger payload for RRC-Reconf ig-Complete (carried on RUSCH) .

[0081] Step 10 (item 510) : the UE 110 transmits RRC- Reconf iguration-Complete and additional ST traffic on the allocated RUSCH. In particular, at 510 the UE transmits to the target node (target cell) 170-2 RUSCH containing RRC-Reconf iguration-Complete and uplink ST related traffic and/or the ST headroom.

[0082] Step 11 (item 511) : item 511 is PDSCH transmission for sending MsgB and also downlink ST traffic. In particular, at 511 the target node (target cell) 170-2 transmits to the UE 110 Msg-B containing DL ST related traffic .

[0083] Step 12 (item 512) : At 512, there is HO completion by the UE 110, the source node (source cell) 170-1 and the target node (target cell) 170-2.

[0084] FIG. 6 is an example apparatus 600, which may be implemented in hardware, configured to early PDCCH / CG activation based on survival time, based on the examples described herein. The apparatus 600 comprises a processor 602, at least one memory 604 including computer program code 605, wherein the at least one memory 604 and the computer program code 605 are configured to, with the at least one processor 602, cause the apparatus to implement a process, component, module, or function (collectively activation 606) to implement early PDCCH / CG activation based on survival time. The at least one memory 604 may comprise a non-transitory memory or a transitory memory. The apparatus 600 optionally includes a display and/or I/O interface 608 that may be used to display aspects or a status of any of the methods described herein (e.g., as one of the methods is being performed or at a subsequent time) , or to receive input for example via keypad. The apparatus 600 includes one or more network (NW) interfaces (I/F(s) ) 610. The NW I/F(s) 610 may be wired and/or wireless and communicate over the Internet /other network (s) via any communication technique. The NW I/F(s) 610 may comprise one or more transmitters and one or more receivers. The N/W I/F(s) 610 may comprise standard well-known components such as an amplifier, filter, frequency-converter, (de) modulator, and encoder/decoder circuitry ( ies ) and one or more antennas. In some examples, the processor 602 is configured to implement activation 606 without use of memory 604.

[0085] The memory 604 may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The memory 604 may comprise a database for storing data. Interface 612 enables data communication between the various items of apparatus 600, as shown in FIG. 6. Interface 612 may be one or more buses, or interface 612 may be one or more software interfaces configured to pass data within computer program code 605. For example, the interface 612 may be an object-oriented interface in software, or the interface 612 may be one or more buses such as address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. The apparatus 600 need not comprise each of the features mentioned, or may comprise other features as well.

[0086] The apparatus 600 may be an embodiment of any of the apparatuses shown in FIG. 1, FIG. 3, FIG. 4, and FIG. 5, including any combination of those. Thus, the apparatus 600 may be UE 110, RAN node 170, or Network Element (s) 190. Thus, processor 602 may correspond to processor (s) 120, processor (s) 152, or processor (s) 175, memory 3104 may correspond to memory (ies) 125, memory (ies) 155, or memory (ies) 171, computer program code 605 may correspond to computer program code 123, module 140-1, module 140-2, computer program code 153, module 150-1, module 150-2, or computer program code 173, and NW I/F(s) 610 may correspond to N/W I/F(s) 161 or N/W I/F(s) 180. Alternatively, apparatus 600 may not correspond to either of UE 110, RAN node 170, or Network element (s) 190 (for example, apparatus 600 may be a remote or a cloud apparatus) .

[0087] FIG. 7 is an example method 700 to implement early PDCCH / CG activation based on survival time, based on the examples described herein. At 702, the method includes receiving a handover command comprising at least one survival time preamble associated with a survival time headroom threshold. At 704, the method includes transmitting the at least one survival time preamble in response to a survival time headroom being lower or higher than the survival time headroom threshold, otherwise transmitting another preamble type. At 706, the method includes receiving an early configured grant for uplink or downlink activation with downlink control information over a physical downlink control channel based on the transmitted preamble . Method 700 may be implemented by UE 110 .

[ 0088 ] FIG . 8 is another example method 800 to implement early PDCCH / CG activation based on survival time , based on the examples described herein . At 802 , the method includes transmitting a handover request comprising a survival time headroom status . At 804 , the method includes receiving an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble associated with a survival time headroom threshold . At 806 , the method includes transmitting the handover command to a user equipment with a configuration message . At 808 , the method includes wherein the survival time preamble and survival time headroom threshold are used to determine whether the user equipment is provided an early configured grant for uplink or downlink . Method 800 may be implemented by RAN node 170 , such as source node 170- 1 .

[ 0089 ] FIG . 9 is another example method 900 to implement early PDCCH / CG activation based on survival time , based on the examples described herein . At 902 , the method includes providing a handover command comprising at least one survival time preamble associated with a survival time headroom threshold . At 904 , the method includes receiving the at least one survival time preamble in response to a survival time headroom being higher or lower than the survival time headroom threshold, otherwise receiving another preamble type . At 906 , the method includes providing an early configured grant for uplink or downlink activation with downlink control information over a physical downlink control channel at least in response to receiving the survival time preamble . Method 900 may be implemented by a RAN node 170 , such as target node 170-2 .

[ 0090 ] FIG . 10 shows a user equipment method 1000 , based on the examples described herein . At 1002 , the method includes receiving a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold . At 1004 , the method includes selecting the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom. At 1006 , the method includes comparing the survival time headroom to the survival time headroom threshold . At 1008 , the method includes transmitting the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmitting at least one preamble di f ferent from the at least one survival time preamble . At 1010 , the method includes wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from a user equipment . Method 1000 may be implemented by the UE 110 .

[ 0091 ] FIG . 11 shows a target node method 1100 , based on the examples described herein . At 1102 , the method includes receiving a handover request comprising a survival time headroom status . At 1104 , the method includes transmitting an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold . At 1106 , the method includes receiving the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receiving at least one preamble di f ferent from the at least one survival time preamble . At 1108 , the method includes wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from the user equipment . Method 1100 may be implemented by a RAN node 170 , such as target node 170-2 .

[ 0092 ] FIG . 12 shows a source node method 1200 , based on the examples described herein . At 1202 , the method includes transmitting a handover request comprising a survival time headroom status . At 1204 , the method includes receiving an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold . At 1206 , the method includes transmitting the handover command to a user equipment . At 1208 , the method includes wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment . At 1210 , the method includes wherein the at least one survival time preamble i s transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble different from the at least one survival time preamble is transmitted. Method 1200 may be implemented by a RAN node 170, such as source node 170- 1.

[0093] References to a 'computer' , 'processor' , etc. should be understood to encompass not only computers having different architectures such as single/multi-processor architectures and sequential (Von Neumann) /parallel architectures but also specialized circuits such as field- programmable gate arrays (FPGA) , systems on a chip (SoC) , application specific circuits (e.g. ASIC) , signal processing devices and other processing circuitry. References to computer program, instructions, code etc. should be understood to encompass software for a programmable processor or firmware such as, for example, the programmable content of a hardware device or instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device etc.

[0094] As used herein, the term 'circuitry' , 'circuit' and variants may refer to any of the following: (a) hardware circuit implementations, such as implementations in analog and/or digital circuitry, and (b) combinations of circuits and software (and/or firmware) , such as (as applicable) : (i) a combination of processor (s) or (ii) portions of processor ( s ) /software including digital signal processor ( s ) , software, and memory (ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor ( s ) or a portion of a microprocessor ( s ) , that require software or firmware for operation, even i f the software or firmware is not physically present . As a further example , as used herein, the term 'circuitry' would also cover an implementation of merely a processor ( or multiple processors ) or a portion of a processor and its ( or their ) accompanying software and/or firmware . The term ' circuitry' would also cover, for example and i f applicable to the particular element , a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device , or another network device . Circuitry or circuit may also be used to mean a function or a proces s used to execute a method .

[ 0095 ] An example apparatus includes at least one processor ; and at least one memory including computer program code ; wherein the at least one memory and the computer program code are configured to , with the at least one processor, cause the apparatus at least to : receive a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; select the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom; compare the survival time headroom to the survival time headroom threshold; and transmit the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmit at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from a user equipment .

[ 0096 ] The apparatus may further include wherein the survival time headroom comprises : a time remaining before a communication service transitions to a down state ; or a number of remaining consecutive errors that can be received before the communication service transitions to the down state .

[ 0097 ] The apparatus may further include wherein the at least one survival time headroom threshold comprises : a time before a communication service transitions to a down state ; or a number of consecutive errors that can be received before the communication service transitions to the down state .

[ 0098 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : perform a handover from a source node to a target node , based on the handover command .

[ 0099 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : decide whether to use the at least one survival time preamble based on the survival time headroom .

[ 00100 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : receive an indication of activation of a configured grant for early downlink transmission with downlink control information over a physical downlink control channel .

[ 00101 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : receive an indication of activation of a configured grant for early uplink transmission with downlink control information over a physical downlink control channel , together with a timing advance .

[ 00102 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : perform early monitoring of a physical downlink control channel upon transmitting of the at least one survival time preamble .

[ 00103 ] The apparatus may further include wherein the early monitoring is performed to monitor a cell radio network temporary identi fier rather than a random access radio network temporary identi fier for receiving a physical downlink shared channel or physical uplink shared channel allocation or downlink control information indicating early activation of a configured grant for uplink transmi ssion and downlink transmission, wherein the physical downlink shared channel or physical uplink shared channel provides a timing advance value to be used for an uplink grant .

[ 00104 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : receive the at least one preamble di f ferent from the at least one survival time preamble together with the at least one survival time preamble .

[ 00105 ] The apparatus may further include wherein the at least one survival time preamble is configured with more of a number of repetitions than the at least one preamble di f ferent from the at least one survival time preamble .

[ 00106 ] The apparatus may further include wherein the at least one preamble di f ferent from the at least one survival time preamble comprises a normal preamble .

[ 00107 ] The apparatus may further include wherein the handover command is received from a source node with a user equipment .

[ 00108 ] The apparatus may further include wherein the at least one survival time preamble or the at least one preamble di f ferent from the at least one survival time preamble is transmitted to a target node of a handover .

[ 00109 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : in response to the survival time headroom not being lower than the at least one survival time threshold at a time of receiving the at least one survival time preamble but reaching a survival time expiry on transmission of a physical uplink shared channel : inform a target node of the survival time headroom within a radio resource control reconfiguration complete message , to enable the target node to modi fy a pending configured grant based on a pending survival time . [ 00110 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : transmit the survival time headroom and/or the at least one survival time headroom threshold within a message of a random access channel procedure .

[ 00111 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : receive an early physical downlink control channel transmission based on the message ; wherein the early physical downl ink control channel transmi ssion allocates a larger payload for a radio resource control reconfiguration message ; wherein the early physical downlink control channel transmission allocates a larger payload for physical uplink shared channel survival time traf fic transmission .

[ 00112 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : transmit the radio resource control reconfiguration message and the survival time traf fic and/or the survival time headroom on the physical uplink shared channel .

[ 00113 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : receive a message related to a random access procedure over a physical downlink shared channel , the message comprising downlink survival time related traf fic . [ 00114 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : receive a configuration grant compris ing a fixed location from a time o f receipt o f the at least one survival time preamble ; and monitor with the user equipment using the configuration grant for downlink allowing reception of a physical downlink shared channel transmission after transmitting the at least one survival time preamble .

[ 00115 ] The apparatus may further include wherein the transmitting of the at least one survival time preamble occurs during mobility in a target cell of a target node .

[ 00116 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : obtain the survival time headroom threshold from a radio access network, the user equipment , or a management entity .

[ 00117 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : receive an indication within a physical downlink control channel of activation of an uplink configured grant from a speci fic time of fset from reception of the physical downlink control channel .

[ 00118 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : in response to transmitting the at least one preamble di f ferent from the at least one survival time preamble , and further in response to not receiving a response from the communication network, reduce the survival time headroom and transmitting the at least one survival time preamble .

[ 00119 ] An example apparatus includes at least one processor ; and at least one memory including computer program code ; wherein the at least one memory and the computer program code are configured to , with the at least one processor, cause the apparatus at least to : receive a handover request comprising a survival time headroom status ; transmit an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and receive the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receive at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment .

[ 00120 ] The apparatus may further include wherein the survival time headroom comprises : a time remaining before a communication service transitions to a down state ; or a number of remaining consecutive errors that can be received before the communication service transitions to the down state . [ 00121 ] The apparatus may further include wherein the at least one survival time headroom threshold comprises : a time before a communication service transitions to a down state ; or a number of consecutive errors that can be received before the communication service transitions to the down state .

[ 00122 ] The apparatus may further include wherein a handover from a source node to the target node is performed with the user equipment based on the handover command .

[ 00123 ] The apparatus may further include wherein the user equipment decides whether to use the at least one survival time preamble based on the survival time headroom .

[ 00124 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : transmit an indication of activation of a configured grant for early downlink transmission with downlink control information over a physical downlink control channel .

[ 00125 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : transmit an indication of activation of a configured grant for early uplink transmission with downlink control information over a physical downlink control channel , together with a timing advance .

[ 00126 ] The apparatus may further include wherein the user equipment performs early monitoring of a physical downlink control channel upon transmission of the at least one survival time preamble .

[ 00127 ] The apparatus may further include wherein the early monitoring is performed to monitor a cell radio network temporary identi fier rather than a random access radio network temporary identi fier for receiving a physical downlink shared channel or physical uplink shared channel allocation or downlink control information indicating early activation of a configured grant for uplink transmi ssion and downlink transmission, wherein the physical downlink shared channel or physical uplink shared channel provides a timing advance value to be used for an uplink grant .

[ 00128 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : transmit the at least one preamble di f ferent from the at least one survival time preamble together with the at least one survival time preamble .

[ 00129 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : configure the at least one survival time preamble with more of a number of repetitions than the at least one preamble di f ferent from the at least one survival time preamble .

[ 00130 ] The apparatus may further include wherein the at least one preamble di f ferent from the at least one survival time preamble comprises a normal preamble . [ 00131 ] The apparatus may further include wherein the handover command is transmitted from a source node to the user equipment .

[ 00132 ] The apparatus may further include wherein the at least one survival time preamble or the at least one preamble di f ferent from the at least one survival time preamble is transmitted to the target node of a handover .

[ 00133 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : in response to the survival time headroom not being lower than the at least one survival time threshold at a time of receiving the at least one survival time preamble but reaching a survival time expiry on transmission of a physical uplink shared channel : receive information comprising the survival time headroom from the user equipment within a radio resource control reconfiguration complete message , to enable the target node to modi fy a pending configured grant based on a pending survival time .

[ 00134 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : receive the survival time headroom and/or the at least one survival time headroom threshold within a message of a random access channel procedure .

[ 00135 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : transmit an early physical downlink control channel transmission based on the message ; wherein the early physical downl ink control channel transmi ssion allocates a larger payload for a radio resource control reconfiguration message ; wherein the early physical downlink control channel transmi ssion allocates a larger payload for physical uplink shared channel survival time traf fic transmission .

[ 00136 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : receive the radio resource control reconfiguration message and the survival time traf fic and/or the survival time headroom on the physical uplink shared channel .

[ 00137 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : receive a message related to a random access procedure over a physical downlink shared channel , the message comprising downl ink survival time related traf fic .

[ 00138 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : transmit a configuration grant comprising a f ixed location from a time of receipt o f the at least one survival time preamble ; wherein the user equipment monitors using the configuration grant for downlink allowing reception of a physical downlink shared channel transmission after survival time preamble transmission . [ 00139 ] The apparatus may further include wherein the receiving of the at least one survival time preamble occurs during mobility of the user equipment in a target cell of the target node .

[ 00140 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : obtain the survival time headroom threshold from a radio access network, the user equipment , or a management entity .

[ 00141 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : provide an indication within a physical downlink control channel of activation of an uplink configured grant from a speci fic time of fset from reception of the physical downlink control channel .

[ 00142 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor, cause the apparatus at least to : in response to receiving the at least one preamble di f ferent from the at least one survival time preamble , and further in response to the user equipment not receiving a response from a network, receive the at least one survival time preamble , wherein the survival time headroom is reduced .

[ 00143 ] An example apparatus includes at least one processor ; and at least one memory including computer program code ; wherein the at least one memory and the computer program code are configured to , with the at least one processor, cause the apparatus at least to : transmit a handover request comprising a survival time headroom status ; receive an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and transmit the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downlink transmi ssion prior to transmission of a handover complete message from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

[ 00144 ] The apparatus may further include wherein the survival time headroom comprises : a time remaining before a communication service transitions to a down state ; or a number of remaining consecutive errors that can be received before the communication service transitions to the down state .

[ 00145 ] The apparatus may further include wherein the at least one survival time headroom threshold comprises : a time before a communication service transitions to a down state ; or a number of consecutive errors that can be received before the communication service transitions to the down state . [ 00146 ] The apparatus may further include wherein a handover from a source node to the target node is performed with the user equipment based on the handover command .

[ 00147 ] The apparatus may further include wherein the user equipment decides whether to use the at least one survival time preamble based on the survival time headroom .

[ 00148 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : transmit an indication of activation of a configured grant for early downlink transmission with downlink control information over a physical downlink control channel .

[ 00149 ] The apparatus may further include wherein an indication of activation of a configured grant for early uplink transmission is transmitted with downlink control information over a physical downlink control channel , together with a timing advance .

[ 00150 ] The apparatus may further include wherein the user equipment performs early monitoring of a physical downlink control channel upon transmission of the at least one survival time preamble .

[ 00151 ] The apparatus may further include wherein the early monitoring is performed to monitor a cell radio network temporary identi fier rather than a random access radio network temporary identi fier for receiving a physical downlink shared channel or physical uplink shared channel allocation or downlink control information indicating early activation of a configured grant for uplink transmi ssion and downlink transmission, wherein the physical downlink shared channel or physical uplink shared channel provides a timing advance value to be used for an uplink grant .

[ 00152 ] The apparatus may further include wherein the acknowledgement comprises at least one preamble di f ferent from the at least one survival time preamble together with the at least one survival time preamble .

[ 00153 ] The apparatus may further include wherein the at least one survival time preamble is configured with more of a number o f repetitions than the at least one preamble di f ferent from the at least one survival time preamble .

[ 00154 ] The apparatus may further include wherein the at least one preamble di f ferent from the at least one survival time preamble comprises a normal preamble .

[ 00155 ] The apparatus may further include wherein the handover command is transmitted from a source node to the user equipment .

[ 00156 ] The apparatus may further include wherein the at least one survival time preamble or the at least one preamble di f ferent from the at least one survival time preamble is transmitted to a target node of a handover .

[ 00157 ] The apparatus may further include wherein : in response to the survival time headroom not being lower than the at least one survival time threshold at a time of receiving the at least one survival time preamble but reaching a survival time expiry on transmission of a physical uplink shared channel : information comprising the survival time headroom is transmitted with the user equipment within a radio resource control reconfiguration complete message , to enable the target node to modi fy a pending configured grant based on a pending survival time .

[ 00158 ] The apparatus may further include wherein the survival time headroom and/or the at least one survival time headroom threshold is transmitted to the target node within a message of a random access channel procedure .

[ 00159 ] The apparatus may further include wherein : an early physical downlink control channel transmission is transmitted with the target node based on the message ; the early physical downlink control channel transmi ssion allocates a larger payload for a radio resource control reconfiguration message ; and wherein the early physical downlink control channel transmi ssion allocates a larger payload for physical uplink shared channel survival time traf fic transmission .

[ 00160 ] The apparatus may further include wherein the radio resource control reconfiguration message and the survival time traf fic and/or the survival time headroom is transmitted with the user equipment to the target node on the physical uplink shared channel .

[ 00161 ] The apparatus may further include wherein a message related to a random access procedure is transmitted with the target node to the user equipment over a physical downlink shared channel , the message comprising downl ink survival time related traf fic .

[ 00162 ] The apparatus may further include wherein : a configuration grant comprising a fixed location from a time of receipt of the at least one survival time preamble is transmitted from the target node to the user equipment ; wherein the user equipment monitors using the configuration grant for downlink allowing reception of a physical downlink shared channel transmi ssion after survival time preamble transmission .

[ 00163 ] The apparatus may further include wherein the transmission of the at least one survival time preamble occurs during mobility of the user equipment in a target cell of the target node .

[ 00164 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : obtain the survival time headroom threshold from a radio access network, the user equipment , or a management entity .

[ 00165 ] The apparatus may further include wherein the at least one memory and the computer program code are further configured to , with the at least one processor , cause the apparatus at least to : provide an indication within a physical downlink control channel of activation of an uplink configured grant from a speci fic time of fset from reception of the physical downlink control channel .

[ 00166 ] The apparatus may further include wherein in response to the at least one preamble di f ferent from the at least one survival time preamble being transmitted, and further in response to the user equipment not receiving a response from a network, the at least one survival time preamble is transmitted and the survival time headroom is reduced . [ 00167 ] An example method includes receiving a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; selecting the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom; comparing the survival time headroom to the survival time headroom threshold; and transmitting the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmitting at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from a user equipment .

[ 00168 ] An example method includes receiving a handover request comprising a survival time headroom status ; transmitting an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and receiving the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receiving at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment .

[ 00169 ] An example method includes transmitting a handover request comprising a survival time headroom status ; receiving an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and transmitting the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

[ 00170 ] An example apparatus includes means for receiving a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; means for selecting the at least one survival time preamble from a set of the at least one survival time preamble, based on a survival time headroom; means for comparing the survival time headroom to the survival time headroom threshold; and means for, transmitting the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmitting at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from a user equipment .

[ 00171 ] An example apparatus includes means for receiving a handover request comprising a survival time headroom status ; means for transmitting an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and means for, receiving the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receiving at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from the user equipment .

[ 00172 ] An example apparatus includes means for transmitting a handover request comprising a survival time headroom status ; means for receiving an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and means for transmitting the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

[ 00173 ] An example non-transitory program storage device readable by a machine , tangibly embodying a program of instructions executable with the machine for performing operations is provided, the operations comprising : receiving a handover command compri sing at least one survival time preamble respectively associated with at least one survival time headroom threshold; selecting the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom; comparing the survival time headroom to the survival time headroom threshold; and transmitting the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmitting at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from a user equipment .

[ 00174 ] An example non-transitory program storage device readable by a machine , tangibly embodying a program of instructions executable with the machine for performing operations is provided, the operations comprising : receiving a handover request comprising a survival time headroom status ; transmitting an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and receiving the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receiving at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment .

[ 00175 ] An example non-transitory program storage device readable by a machine , tangibly embodying a program of instructions executable with the machine for performing operations is provided, the operations comprising : transmitting a handover request comprising a survival time headroom status ; receiving an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and transmitting the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete mes sage from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

[ 00176 ] It should be understood that the foregoing description is only illustrative . Various alternatives and modi fications may be devised by those s ki lled in the art . For example , features recited in any dependent claims could be combined with each other in any suitable combination ( s ) . In addition, features from dif ferent embodiments described above could be selectively combined into a new embodiment . Accordingly, the description is intended to embrace all such alternatives , modi fications and variations which fall within the scope of any claims .

[ 00177 ] The following acronyms and abbreviations that may be found in the speci fication and/or the drawing figures are defined as follows :

3GPP third generation partnership proj ect ( or proj ect partner )

4G fourth generation

5G fi fth generation

5GC 5G core network

5GS 5G system ACK acknowledgement

AF application function

AMF access (or core access) and mobility management function

ASIC application-specific integrated circuit

CFRA contention-free random-access

CG configured grant

C-RNTI cell RNTI

CU central unit or centralized unit

DCI downlink control indication/inf ormation

DL downlink

DSP digital signal processor

DU distributed unit eNB evolved/enhanced Node B (e.g., an LTE base station)

EN-DC E-UTRA-NR dual connectivity en-gNB node providing NR user plane and control plane protocol terminations towards the UE, and acting as a secondary node in EN-DC

E-UTRA evolved universal terrestrial radio access, i.e., the LTE radio access technology Fl control interface between CU and DU

FPGA field programmable gate array gNB next generation Node B, base station for

5G/NR, i.e., a node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface to the 5GC

HO handover

I/F interface

IIoT industrial loT loT internet of things I /O input/output LTE long term evolution ( 4G)

MAC medium access control MME mobility management entity

Msg3 message 3 Msg-A message A

MsgB message B ng or NG new generation ng-eNB new generation eNB NG-RAN new generation radio access network NR new radio ( 5G)

NW or N/W network PDCCH physical downlink control channel PDCP packet data convergence protocol PDSCH physical downlink shared channel

PHY physical layer

PUSCH physical uplink shared channel

QoS quality of service RACH random access channel

RAN radio access network

RAR random access response

RA-RNTI random access RNTI

Rel- release

RLC radio link control

RNTI radio network temporary identi fier

RRC radio resource conf iguration/control

RRH remote radio head

RU radio unit

Rx or RX receiver/ receive/ reception

SA2 service and system aspects working group 2

SDAP service data adaptation protocol SGW serving gateway SMF session management function

SoC system(s) on a chip

SPS semi persistent scheduling

ST survival time

TR technical report

TS technical specification

TSCAI time sensitive communications assistance information

Tx or TX transmitter/ transmit/ transmission

UE user equipment (e.g., a wireless, typically mobile device)

UL uplink

UPF user plane function

URLLC ultra-reliable low latency communication

Claims

CLAIMS What is claimed is :

1 . An apparatus comprising : at least one processor ; and at least one memory including computer program code ; wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to : receive a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; select the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom; compare the survival time headroom to the survival time headroom threshold; and transmit the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmit at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from a user equipment .

2. The apparatus of claim 1, wherein the survival time headroom comprises: a time remaining before a communication service transitions to a down state; or a number of remaining consecutive errors that can be received before the communication service transitions to the down state.

3. The apparatus of any one of claims 1 to 2, wherein the at least one survival time headroom threshold comprises: a time before a communication service transitions to a down state; or a number of consecutive errors that can be received before the communication service transitions to the down state .

4. The apparatus of any one of claims 1 to 3, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to: perform a handover from a source node to a target node, based on the handover command.

5. The apparatus of any one of claims 1 to 4, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to: decide whether to use the at least one survival time preamble based on the survival time headroom.

6. The apparatus of any one of claims 1 to 5, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to: receive an indication of activation of a configured grant for early downlink transmission with downlink control information over a physical downlink control channel.

7. The apparatus of any one of claims 1 to 6, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to: receive an indication of activation of a configured grant for early uplink transmission with downlink control information over a physical downlink control channel, together with a timing advance.

8. The apparatus of any one of claims 1 to 7, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to: perform early monitoring of a physical downlink control channel upon transmitting of the at least one survival time preamble.

9. The apparatus of claim 8, wherein the early monitoring is performed to monitor a cell radio network temporary identifier rather than a random access radio network temporary identifier for receiving a physical downlink shared channel or physical uplink shared channel allocation or downlink control information indicating early activation of a configured grant for uplink transmission and downlink transmission, wherein the physical downlink shared channel or physical uplink shared channel provides a timing advance value to be used for an uplink grant .

10 . The apparatus of any one of claims 1 to 9 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : receive the at least one preamble di f ferent from the at least one survival time preamble together with the at least one survival time preamble .

11 . The apparatus of any one of claims 1 to 10 , wherein the at least one survival time preamble is configured with more of a number of repetitions than the at least one preamble di f ferent from the at least one survival time preamble .

12 . The apparatus of any one of claims 1 to 11 , wherein the at least one preamble di f ferent from the at least one survival time preamble comprises a normal preamble .

13 . The apparatus of any one of claims 1 to 12 , wherein the handover command is received from a source node with a user equipment .

14 . The apparatus of any one of claims 1 to 13 , wherein the at least one survival time preamble or the at least one preamble di f ferent from the at least one survival time preamble is transmitted to a target node of a handover .

15 . The apparatus of any one of claims 1 to 14 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : in response to the survival time headroom not being lower than the at least one survival time threshold at a time of receiving the at least one survival time preamble but reaching a survival time expiry on transmission of a physical uplink shared channel : inform a target node of the survival time headroom within a radio resource control reconfiguration complete message , to enable the target node to modi fy a pending configured grant based on a pending survival time .

16 . The apparatus of any one of claims 1 to 15 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : transmit the survival time headroom and/or the at least one survival time headroom threshold within a message of a random access channel procedure .

17 . The apparatus of claim 16 , wherein the at least one memory and the computer program code are further configured to , with the at least one processor, cause the apparatus at least to : receive an early physical downl ink control channel transmission based on the message ; wherein the early physical downl ink control channel transmission allocates a larger payload for a radio resource control reconfiguration message ; wherein the early physical downl ink control channel transmission allocates a larger payload for physical uplink shared channel survival time traf fic transmission .

18 . The apparatus of claim 17 , wherein the at least one memory and the computer program code are further configured to , with the at least one processor, cause the apparatus at least to : transmit the radio resource control reconfiguration message and the survival time traffic and/or the survival time headroom on the physical uplink shared channel .

19 . The apparatus of any one of claims 1 to 18 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : receive a message related to a random access procedure over a physical downl ink shared channel , the message comprising downlink survival time related traf fic .

20 . The apparatus of any one of claims 1 to 19 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : receive a configuration grant comprising a fixed location from a time of receipt of the at least one survival time preamble ; and monitor with the user equipment using the configuration grant for downlink allowing reception of a physical downlink shared channel transmission after transmitting the at least one survival time preamble .

21 . The apparatus of any one of claims 1 to 20 , wherein the transmitting of the at least one survival time preamble occurs during mobility in a target cell of a target node .

22 . The apparatus of any one of claims 1 to 21 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : obtain the survival time headroom threshold from a radio access network, the user equipment , or a management entity .

23 . The apparatus of any one of claims 1 to 22 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : receive an indication within a physical downl ink control channel of activation of an uplink configured grant from a speci fic time offset from reception of the physical downlink control channel .

24 . The apparatus of any one of claims 1 to 23 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : in response to transmitting the at least one preamble di f ferent from the at least one survival time preamble , and further in response to not receiving a response from the communication network, reduce the survival time headroom and transmitting the at least one survival time preamble .

25 . An apparatus comprising : at least one processor ; and at least one memory including computer program code ; wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to : receive a handover request comprising a survival time headroom status ; transmit an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and receive the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receive at least one preamble dif ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from the user equipment .

26 . The apparatus of claim 25 , wherein the survival time headroom comprises : a time remaining before a communication service transitions to a down state ; or a number of remaining consecutive errors that can be received before the communication service transitions to the down state .

27 . The apparatus of any one of claims 25 to 26 , wherein the at least one survival time headroom threshold comprises : a time before a communication service transitions to a down state ; or a number of consecutive errors that can be received before the communication service transitions to the down state .

28 . The apparatus of any one of claims 25 to 27 , wherein a handover from a source node to the target node is performed with the user equipment based on the handover command .

29 . The apparatus of any one of claims 25 to 28 , wherein the user equipment decides whether to use the at least one survival time preamble based on the survival time headroom .

30 . The apparatus of any one of claims 25 to 29 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : transmit an indication of activation of a configured grant for early downl ink transmi ssion with downlink control information over a physical downlink control channel .

31 . The apparatus of any one of claims 25 to 30 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : transmit an indication of activation of a configured grant for early uplink transmission with downlink control information over a physical downl ink control channel , together with a timing advance .

32 . The apparatus of any one of claims 25 to 31 , wherein the user equipment performs early monitoring of a physical downlink control channel upon transmission of the at least one survival time preamble .

33 . The apparatus of claim 32 , wherein the early monitoring is performed to monitor a cell radio network temporary identi fier rather than a random access radio network temporary identi fier for receiving a physical downlink shared channel or physical uplink shared channel allocation or downlink control information indicating early activation of a configured grant for uplink transmission and downlink transmission, wherein the physical downlink shared channel or physical uplink shared channel provides a timing advance value to be used for an uplink grant .

34 . The apparatus of any one of claims 25 to 33 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : transmit the at least one preamble di f ferent from the at least one survival time preamble together with the at least one survival time preamble .

35 . The apparatus of any one of claims 25 to 34 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : configure the at least one survival time preamble with more of a number of repetitions than the at least one preamble di f ferent from the at least one survival time preamble .

36 . The apparatus of any one of claims 25 to 35 , wherein the at least one preamble di f ferent from the at least one survival time preamble comprises a normal preamble .

37 . The apparatus of any one of claims 25 to 36 , wherein the handover command is transmitted from a source node to the user equipment .

38 . The apparatus of any one of claims 25 to 37 , wherein the at least one survival time preamble or the at least one preamble di f ferent from the at least one survival time preamble is transmitted to the target node of a handover .

39 . The apparatus of any one of claims 25 to 38 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : in response to the survival time headroom not being lower than the at least one survival time threshold at a time of receiving the at least one survival time preamble

70 but reaching a survival time expiry on transmission of a physical uplink shared channel : receive information comprising the survival time headroom from the user equipment within a radio resource control reconfiguration complete message , to enable the target node to modi fy a pending configured grant based on a pending survival time .

40 . The apparatus of any one of claims 25 to 39 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : receive the survival time headroom and/or the at least one survival time headroom threshold within a message of a random access channel procedure .

41 . The apparatus of claim 40 , wherein the at least one memory and the computer program code are further configured to , with the at least one processor, cause the apparatus at least to : transmit an early physical downl ink control channel transmission based on the message ; wherein the early physical downl ink control channel transmission allocates a larger payload for a radio resource control reconfiguration message ; wherein the early physical downl ink control channel transmission allocates a larger payload for physical uplink shared channel survival time traf fic transmission .

42 . The apparatus of claim 41 , wherein the at least one memory and the computer program code are further configured

71 to , with the at least one processor, cause the apparatus at least to : receive the radio resource control reconfiguration message and the survival time traffic and/or the survival time headroom on the physical uplink shared channel .

43 . The apparatus of any one of claims 25 to 42 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : receive a message related to a random access procedure over a physical downl ink shared channel , the message comprising downlink survival time related traf fic .

44 . The apparatus of any one of claims 25 to 43 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : transmit a configuration grant comprising a fixed location from a time of receipt of the at least one survival time preamble ; wherein the user equipment monitors using the configuration grant for downlink allowing reception of a physical downlink shared channel transmission after survival time preamble transmission .

45 . The apparatus of any one of claims 25 to 44 , wherein the receiving of the at least one survival time preamble occurs during mobility of the user equipment in a target cell of the target node .

72

46 . The apparatus of any one of claims 25 to 45 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : obtain the survival time headroom threshold from a radio access network, the user equipment , or a management entity .

47 . The apparatus of any one of claims 25 to 46 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : provide an indication within a physical downl ink control channel of activation of an uplink configured grant from a speci fic time offset from reception of the physical downlink control channel .

48 . The apparatus of any one of claims 25 to 47 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : in response to receiving the at least one preamble di f ferent from the at least one survival time preamble , and further in response to the user equipment not receiving a response from a network, receive the at least one survival time preamble , wherein the survival time headroom is reduced .

49 . An apparatus comprising : at least one processor ; and at least one memory including computer program code ;

73 wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to : transmit a handover request compri sing a survival time headroom status ; receive an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and transmit the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

50 . The apparatus of claim 49 , wherein the survival time headroom comprises : a time remaining before a communication service transitions to a down state ; or

74 a number of remaining consecutive errors that can be received before the communication service transitions to the down state .

51 . The apparatus of any one of claims 49 to 50 , wherein the at least one survival time headroom threshold comprises : a time before a communication service transitions to a down state ; or a number of consecutive errors that can be received before the communication service transitions to the down state .

52 . The apparatus of any one of claims 49 to 51 , wherein a handover from a source node to the target node is performed with the user equipment based on the handover command .

53 . The apparatus of any one of claims 49 to 52 , wherein the user equipment decides whether to use the at least one survival time preamble based on the survival time headroom .

54 . The apparatus of any one of claims 49 to 53 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : transmit an indication of activation of a configured grant for early downl ink transmi ssion with downlink control information over a physical downlink control channel .

55 . The apparatus of any one of claims 49 to 54 , wherein an indication of activation of a configured grant for early uplink transmission is transmitted with downlink control

75 information over a physical downl ink control channel , together with a timing advance .

56 . The apparatus of any one of claims 49 to 55 , wherein the user equipment performs early monitoring of a physical downlink control channel upon transmission of the at least one survival time preamble .

57 . The apparatus of claim 56 , wherein the early monitoring is performed to monitor a cell radio network temporary identi fier rather than a random access radio network temporary identi fier for receiving a physical downlink shared channel or physical uplink shared channel allocation or downlink control information indicating early activation of a configured grant for uplink transmission and downlink transmission, wherein the physical downlink shared channel or physical uplink shared channel provides a timing advance value to be used for an uplink grant .

58 . The apparatus of any one of claims 49 to 57 , wherein the acknowledgement comprises at least one preamble di f ferent from the at least one survival time preamble together with the at least one survival time preamble .

59 . The apparatus of any one of claims 49 to 58 , wherein the at least one survival time preamble is configured with more of a number of repetitions than the at least one preamble di f ferent from the at least one survival time preamble .

60 . The apparatus of any one of claims 49 to 59 , wherein the at least one preamble di f ferent from the at least one survival time preamble comprises a normal preamble .

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61 . The apparatus of any one of claims 49 to 60 , wherein the handover command is transmitted from a source node to the user equipment .

62 . The apparatus of any one of claims 49 to 61 , wherein the at least one survival time preamble or the at least one preamble di f ferent from the at least one survival time preamble is transmitted to a target node of a handover .

63 . The apparatus of any one of claims 49 to 62 , wherein : in response to the survival time headroom not being lower than the at least one survival time threshold at a time of receiving the at least one survival time preamble but reaching a survival time expiry on transmission of a physical uplink shared channel : information comprising the survival time headroom i s transmitted with the user equipment within a radio resource control reconfiguration complete message , to enable the target node to modi fy a pending configured grant based on a pending survival time .

64 . The apparatus of any one of claims 49 to 63 , wherein the survival time headroom and/or the at least one survival time headroom threshold is transmitted to the target node within a message of a random access channel procedure .

65 . The apparatus of claim 64 , wherein : an early physical downlink control channel transmission is transmitted with the target node based on the message ;

77 the early physical downlink control channel transmission allocates a larger payload for a radio resource control reconfiguration message ; and wherein the early physical downl ink control channel transmission allocates a larger payload for physical uplink shared channel survival time traf fic transmission .

66 . The apparatus of claim 65 , wherein the radio resource control reconfiguration message and the survival time traf fic and/or the survival time headroom is transmitted with the user equipment to the target node on the physical uplink shared channel .

67 . The apparatus of any one of claims 49 to 66 , wherein a message related to a random access procedure is transmitted with the target node to the user equipment over a physical downlink shared channel , the message comprising downl ink survival time related traf fic .

68 . The apparatus of any one of claims 49 to 67 , wherein : a configuration grant compri sing a fixed location from a time of receipt of the at least one survival time preamble is transmitted from the target node to the user equipment ; wherein the user equipment monitors using the configuration grant for downlink allowing reception of a physical downlink shared channel transmission after survival time preamble transmission .

69 . The apparatus of any one of claims 49 to 68 , wherein the transmission of the at least one survival time preamble occurs during mobility of the user equipment in a target cell of the target node .

70 . The apparatus of any one of claims 49 to 69 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : obtain the survival time headroom threshold from a radio access network, the user equipment , or a management entity .

71 . The apparatus of any one of claims 49 to 70 , wherein the at least one memory and the computer program code are further configured to , with the at least one proces sor, cause the apparatus at least to : provide an indication within a physical downl ink control channel of activation of an uplink configured grant from a speci fic time offset from reception of the physical downlink control channel .

72 . The apparatus of any one of claims 49 to 71 , wherein in response to the at least one preamble di f ferent from the at least one survival time preamble being transmitted, and further in response to the user equipment not receiving a response from a network, the at least one survival time preamble is transmitted and the survival time headroom is reduced .

73 . A method comprising : receiving a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold;

79 selecting the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom; comparing the survival time headroom to the survival time headroom threshold; and transmitting the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmitting at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from a user equipment .

74 . A method comprising : receiving a handover request compri sing a survival time headroom status ; transmitting an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and receiving the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold,

80 otherwise receiving at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from the user equipment .

75 . A method comprising : transmitting a handover request comprising a survival time headroom status ; receiving an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and transmitting the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

76 . An apparatus comprising :

81 means for receiving a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; means for selecting the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom; means for comparing the survival time headroom to the survival time headroom threshold; and means for, transmitting the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmitting at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from a user equipment .

77 . An apparatus comprising : means for receiving a handover request comprising a survival time headroom status ; means for transmitting an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and

82 means for, receiving the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receiving at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from the user equipment .

78 . An apparatus comprising : means for transmitting a handover request compri sing a survival time headroom status ; means for receiving an acknowledgement of the handover request , the acknowledgement including information concerning a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and means for transmitting the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being

83 lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

79 . A non-transitory program storage device readable by a machine , tangibly embodying a program of instructions executable with the machine for performing operations , the operations comprising : receiving a handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; selecting the at least one survival time preamble from a set of the at least one survival time preamble , based on a survival time headroom; comparing the survival time headroom to the survival time headroom threshold; and transmitting the at least one survival time preamble in response to the survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise transmitting at least one preamble di f ferent from the at least one survival time preamble ; wherein the transmitted at least one survival time preamble indicates to a communication network a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from a user equipment .

80 . A non-transitory program storage device readable by a machine , tangibly embodying a program of instructions

84 executable with the machine for performing operations , the operations comprising : receiving a handover request compri sing a survival time headroom status ; transmitting an acknowledgement of the handover request , the acknowledgement including information concerning a handover command for a user equipment comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and receiving the at least one survival time preamble in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise receiving at least one preamble di f ferent from the at least one survival time preamble ; wherein the received at least one survival time preamble indicates to a target node a request to start early uplink and/or downl ink transmission prior to transmission of a handover complete message from the user equipment .

81 . A non-transitory program storage device readable by a machine , tangibly embodying a program of instructions executable with the machine for performing operations , the operations comprising : transmitting a handover request comprising a survival time headroom status ; receiving an acknowledgement of the handover request , the acknowledgement including information concerning a

85 handover command comprising at least one survival time preamble respectively associated with at least one survival time headroom threshold; and transmitting the handover command to a user equipment ; wherein the handover command is configured to be used with the user equipment to determine whether to transmit at least one survival time preamble that indicates to a target node a request to start early uplink and/or downlink transmission prior to transmission of a handover complete message from the user equipment ; wherein the at least one survival time preamble is transmitted in response to a survival time headroom being lower or higher than the at least one survival time headroom threshold, otherwise at least one preamble di f ferent from the at least one survival time preamble is transmitted .

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