Distributed control in wireless systems
Systems, procedures, and instrumentalities are disclosed for distributed control in wireless systems, such as 5G flexible radio access technology (RAT) (5gFLEX). Example procedures are provided for WTRU and network operation associated with a distributed control plane architecture, connectionless data transfer and dedicated system information acquisition. Distributed control may be provided, for example, by replicating a plurality of access control functions (ACFs) using a plurality of instances in a plurality of different transmission/reception points (TRPs) with multi-connectivity. The plurality of TRPs may concurrently provide control services to a WTRU. Centralized control functions may manage core network connectivity and/or a plurality of user plane instances for the WTRU and/or may facilitate coordination between the plurality of ACF instances for the WTRU in the plurality of different TRPs of the WTRU's configuration.
1. A wireless transmit/receive unit (WTRU) in communication with a communication network, the WTRU comprising:
a memory;
a processor, the processor configured at least to:
determine to request one or more system information (SI) messages from the communication network; and
determine whether a transmission of the one or more SI message from the communication network will utilize at least one beamformed communication or a non-beamformed communication based on one or more communication parameters, wherein the one or more communication parameters include a frequency band of the transmission or a quality of a downlink signal; and
a transceiver, the transceiver configured at least to:
receive at least one of the one or more SI messages from the communication network via the at least one beamformed communication or the non-beamformed communication in accordance with a result of determining whether the transmission of the one or more SI message from the communication network will utilize the at least one beamformed communication or the non-beamformed communication,
wherein the one or more communication parameters further include information provided in a broadcast message, the transceiver being further configured to:
receive the broadcast message,
the processor being further configured to:
identity the information in the broadcast message; and
determine that the transmission of the one or more SI messages from the communication network utilizes at least one beamformed communication based on the information in the broadcast message.
2. The WTRU of claim 1 , wherein the one or more communication parameters include the frequency band of the transmission, the processor being further configured to:
compare the frequency band of the transmission to a predetermined threshold; and
determine that the transmission of the one or more SI messages from the communication network utilizes at least one beamformed communication based on the frequency band of the transmission exceeding the predetermined threshold.
3. The WTRU of claim 1 , wherein the one or more communication parameters further include a characteristic of the downlink signal, the transceiver being further configured to:
receive the downlink signal,
the processor being further configured to:
identify the characteristic of the downlink signal; and
determine that the transmission of the one or more SI messages from the communication network utilizes at least one beamformed communication based on the identified characteristic of the downlink signal.
4. The WTRU of claim 3 , wherein the downlink signal includes a reference signal.
5. The WTRU of claim 4 , wherein the characteristic of the downlink signal includes one or more of: a type of the reference signal, a system signature, a root signature, a basis sequence, or one or more predefined sequence numbers.
6. The WTRU of claim 5 , wherein the type of the reference signal is a synchronization signal.
7. The WTRU of claim 1 , wherein the information provided in the broadcast message is included in at least one of: a master system information block (MIB), or a system information block (SIB), or a system information message.
8. The WTRU of claim 1 , wherein the one or more communication parameters include the quality of the downlink signal, the transceiver being further configured to:
receive the downlink signal,
the processor being further configured to:
measure the quality of the downlink signal; and
determine that the transmission of the one or more SI messages from the communication network utilizes at least one beamformed communication based on the quality of the downlink signal being below a predetermined threshold.
9. The WTRU of claim 8 , wherein the downlink signal includes a reference signal; and the quality of the downlink signal includes a received power of the reference signal.
10. The WTRU of claim 1 , wherein the processor is further configured to initiate an uplink (UL) request to the communication network for the one or more SI messages.
11. A wireless transmit/receive unit (WTRU) in communication with a communication network, the WTRU comprising:
a memory;
a processor, the processor configured at least to:
determine to request one or more system information (SI) messages from the communication network;
conduct a beam sweep operation of one or more downlink (DL) beams transmitted from the communication network:
identify at least one DL beam of the one or more DL beams via which to receive the one or more on-demand SI messages based at least in part on the beam sweep operation;
determine one or more uplink (UL) resources with which to communicate information for a WTRU reception of the one or more on-demand SI messages based on a mapping between the one or more UL resources and the at least one DL beam of the one or more DL beams and on the requested one or more on-demand SI messages, the information for the WTRU reception including the at least one DL beam; and
initiate the request fix the one or more on-demand SI messages from the communication network; and
a transceiver, the transceiver configured at least to:
send the request for the one or more on-demand SI messages to the communication network using the one or more UI, resources, the request including the information for the WTRU reception of the one or more on-demand SI messages; and
receive at least one of the one or more on-demand SI messages from the communication network via the at least one DL beam.
12. The WTRU of claim 11 , wherein the one or more UL resources are mapped to the at least one DL beam.
13. The WTRU of claim 11 , wherein the processor is further configured such that the one or more UL resources are determined further based on the at least one DL beam of the one or more DL beams.
14. The WTRU of claim 11 , wherein the processor is further configured such that the request for the one or more on-demand SI messages is sent as part of a Random Access Channel (RACH) transmission.
15. The WTRU of claim 11 , wherein the processor is further configured such that the at least one DL beam of the one or more DL beams is identified based on which of the one or more DL beams at least one of: a synchronization signal, a master system information block (MIB), or essential system information is received in the beam sweep operation.