UE RACH resource configuration selection function and resource prioritization to support slicing
A user device, UE, for a wireless communication network, is connectable to two or more of a plurality of network slices of the wireless communication network, wherein a slice specific random access channel, RACH, resource configuration is associated with one or more of the plurality of slices. Responsive to a first RACH event associated with a first slice, the UE is to determine whether there is an ongoing RACH procedure triggered by a second RACH event associated with a second slice. In case of an ongoing RACH procedure, the UE is to prohibit an additional RACH procedure triggered by the first RACH event associated with the first slice, and/or suspend the additional RACH procedure for a certain time, and/or stop the ongoing RACH procedure and start the additional RACH procedure, and/or modify the ongoing RACH procedure, and/or modify the ongoing RACH procedure to start the additional RACH procedure.
1 . A user device, UE, for a wireless communication network, the UE comprising:
one or more antennas or an antenna array having a plurality of antennas,
a signal processor, and
a transceiver,
wherein the transceiver is connectable to two or more of a plurality of network slices of the wireless communication network, wherein a slice specific random access channel, RACH, resource configuration is associated with one or more of the plurality of slices,
wherein, responsive to a first RACH event associated with a first slice, the signal processor is configured to determine whether there is an ongoing RACH procedure triggered by a second RACH event associated with a second slice, and
wherein, in case of the ongoing RACH procedure, the signal processor is configured to perform at least one of the following:
prohibiting an additional RACH procedure triggered by the first RACH event associated with the first slice,
suspending the additional RACH procedure for a certain time,
stopping the ongoing RACH procedure and start the additional RACH procedure,
modifying the ongoing RACH procedure, and
modifying the ongoing RACH procedure to start the additional RACH procedure.
2 . The user device, UE, of claim 1 , wherein the slice specific RACH resource configuration specifies one or more resource configurations and one or more parameters for a RACH procedure, including at least one of the following:
a physical random-access channel, PRACH, preamble, e.g., comprising a preamble format, a preamble sequence, a sequence length, a subcarrier spacing used for the preamble, a cyclic prefix, a guard time length,
a beam index,
a trigger to switch beams,
resources used for the PRACH, e.g., time and/or frequency and/or spatial resources,
one or more parameters for determining one or more root sequences and cyclic shifts of the root sequences in the PRACH preamble sequence,
an index to a logical root sequence table
a cyclic shift, N CS , and
a set type, e.g., unrestricted, restricted set A, or restricted set B.
3 . The user device, UE, of claim 1 , wherein the signal processor is configured to abort any additional RACH procedure in case there is an ongoing RACH procedure so that, at any point in time, there is only a single ongoing RACH procedure.
4 . The user device, UE, of claim 1 , wherein the signal processor is configured to suspend the additional RACH procedure until the ongoing RACH procedure is completed.
5 . The user device, UE, of claim 4 , wherein the signal processor is configured to store information related to the additional RACH procedure to be used when starting the additional RACH procedure on the second slice, once the ongoing RACH procedure on the first slice is completed.
6 . The user device, UE, of claim 5 , wherein, responsive to the ongoing RACH procedure having failed for a predefined number of times, the signal processor is configured to stop or defer the ongoing RACH procedure, and to start the additional RACH procedure.
7 . The user device, UE, of claim 1 , wherein the signal processor is configured to prohibit or suspend the additional RACH procedure in case at least any one of:
parallel RACH procedures using different slice specific RACH resource configurations are not allowed, e.g., by a certain standard specification, by the defined UE capabilities
parallel RACH procedures using different slice specific RACH resource configurations are disabled, e.g., for a certain cell, a certain UE, a certain service type, a certain priority level, a certain slice, or a certain RACH trigger,
the ongoing RACH procedure has a higher priority than the additional RACH procedure,
the additional RACH procedure uses a different configuration when compared to the ongoing RACH procedure, e.g., a different numerology, a different subcarrier spacing, a different frequency band or a bandwidth part, and
the additional RACH procedure is sent to a different Base Station, BS, or Distributed Unit, DU, than the ongoing RACH procedure.
8 . The user device, UE, of claim 1 , wherein the signal processor is configured to suspend the additional RACH procedure once the ongoing RACH procedure is partly completed.
9 . The user device, UE, of claim 8 , wherein the signal processor is configured to start the additional RACH procedure such that there are no parallel uplink transmissions associated with the ongoing RACH procedure and the additional RACH procedure.
10 . The user device, UE, of claim 8 , wherein the signal processor is configured to start the additional RACH procedure responsive to a certain event associated with the ongoing RACH procedure, the certain event comprising one or more of:
the UE sending a RRC Connection Request Message 3 for the ongoing RACH procedure in an uplink,
the UE receiving a RACH Response, RAR, Message 2 for the ongoing RACH procedure in a downlink,
the UE sending a RACH Preamble Message 1 for the ongoing RACH procedure in the uplink, and
the UE receiving an RRC connection reconfiguration message in the downlink.
11 . The user device, UE, of claim 1 , wherein the signal processor is configured to stop the ongoing RACH procedure and start the additional RACH procedure
during the whole ongoing RACH procedure or until a certain stage of the ongoing RACH procedure, and/or
responsive to one or more pre-emption criteria being fulfilled.
12 . The user device, UE, of claim 11 , wherein the one or more pre-emption criteria comprise one or more of the following:
certain parameters in the RRC RACH resource configuration, like a relative slice priority, or a QoS flow or a logical channel priority,
an event that triggered the RACH procedure, like a PDCCH order, or a handover, or a CHO, or an RRC re-establishment,
a type of user plane message pending for transmission, e.g., to which logical channel, or QoS flow, or PDN session, or slice identity the message belongs to,
a QoS attribute of a user plane message pending for transmission, like priority, or latency or reliability of the logical channel or data flow the message belongs to,
a type of message pending for transmission, e.g., prioritization of an RRC control plane message transmitted over a Signaling Radio Bearer over a user plane message transmitted over a of Data Radio Bearer, and
an entity that triggered the RACH procedure, e.g., prioritization of a UE triggered RACH procedure over a base station triggered RACH procedure or SL-UE triggered RACH procedure, like a group lead UE, or an RSU.
13 . The user device of claim 1 , wherein, to modify the ongoing RACH procedure, the signal processor is configured to modify a certain message, e.g. Msg3, transmitted by the transceiver during the ongoing RACH procedure by incorporating into the certain message, in addition to an indication of the first slice, an indication of the second slice so as to allow a base station to provide in response to the certain message parameters for a configuration of the first and second slices.
14 . The user device of claim 1 , wherein, to modify the ongoing RACH procedure to start the additional RACH procedure, the signal processor is configured to modify a certain message, e.g. Msg3, transmitted by the transceiver during the ongoing RACH procedure by replacing an indication of the first slice with an indication of the second slice so as to allow a base station to provide in response to the certain message parameters for a configuration of the second slice.
15 . The user device, UE, of claim 1 , wherein the additional RACH procedure and the ongoing RACH procedure are triggered at the same time or are triggered within a certain time window.
16 . The user device, UE, of claim 1 , wherein the signal processor is configured or pre-configured to support two or more parallel ongoing RACH procedures, the ongoing RACH procedures being associated with different slices.
17 . The user device, UE, of claim 16 , wherein the signal processor is only permitted to perform two or more PRACH procedures for different slices, if the slice is configured to one or more of
use of a different BWP, and
operate on a different carrier frequency with a frequency gap of delta x between a first radio frequency, e.g. operating on FR1, and a second radio frequency, e.g. operating on FR2.
18 . A wireless communication system, comprising
one or more user devices, UEs, for a wireless communication network,
wherein the UE is connectable to two or more of a plurality of network slices of the wireless communication network, wherein a slice specific random access channel, RACH, resource configuration is associated with one or more of the plurality of slices,
wherein, responsive to a first RACH event associated with a first slice, the UE is to determine whether there is an ongoing RACH procedure triggered by a second RACH event associated with a second slice, and
wherein, in case of an ongoing RACH procedure, the UE is to
prohibit an additional RACH procedure triggered by the first RACH event associated with the first slice, and/or
suspend the additional RACH procedure for a certain time, and/or
stop the ongoing RACH procedure and start the additional RACH procedure, and/or
modify the ongoing RACH procedure, and/or
modify the ongoing RACH procedure to start the additional RACH procedure,
and/or one or more base stations, BSs, for a wireless communication network,
wherein the BS is to support one or more of a plurality of slices of the wireless communication network, wherein a slice specific random access channel, RACH, configuration is associated with one or more of the plurality of slices,
wherein the BS is to configure one or more user devices, UEs, to enable or to disable parallel ongoing RACH procedures.
19 . The wireless communication network of claim 18 , wherein,
the wireless communication network provides the plurality of network slices, and
a radio access network of the wireless communication network, RAN, comprises a cloud-RAN, C-RAN, the C-RAN comprising a plurality of slice specific distributed units, DUs, and one or more central units, CUs, shared by some or all of the slices.
20 . A method for operating a user device, UE, for a wireless communication network, wherein the UE is connectable to two or more of a plurality of network slices of the wireless communication network, wherein a slice specific random access channel, RACH, resource configuration is associated with one or more of the plurality of slices, the method comprising:
responsive to a first RACH event associated with a first slice, determining whether there is an ongoing RACH procedure triggered by a second RACH event associated with a second slice, and
in case of an ongoing RACH procedure,
prohibiting an additional RACH procedure triggered by the first RACH event associated with the first slice, and/or
suspending the additional RACH procedure for a certain time, and/or
stopping the ongoing RACH procedure and start the additional RACH procedure, and/or
modifying the ongoing RACH procedure, and/or
modifying the ongoing RACH procedure to start the additional RACH procedure.