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 method for communicating with a communication network, the method comprising:
determining to request other system information (other-SI) from the communication network;
initiating the request for the other-SI from the communication network as part of a Radom Access Channel (RACH) procedure;
transmitting a RACH signal, the RACH signal including the request for the other-SI in a random access preamble of the RACH signal;
monitoring for a message that includes a minimum SI from the communication network for a predetermined period of time following the transmission of the RACH signal;
determining if the requested other-SI is included in the message that includes the minimum SI upon a detection of the message that includes the minimum SI; and
initiating one or more retransmissions of the RACH signal upon at least one of: the message that includes the minimum SI not being detected, or the other-SI is determined to not be included in a detected message that includes the minimum SI.
2. The method of claim 1 , wherein the predetermined period of time occurs within a random access response time window.
3. The method of claim 2 , further comprising monitoring for a predefined identifier in a control channel within the random access response time window.
4. The method of claim 3 , wherein the predefined identifier is specific to the request of the other-SI.
5. The method of claim 3 , wherein the predefined identifier is a Radio Network Temporary Identifier (RNTI).
6. The method of claim 2 , wherein the message that includes the minimum SI is at least one of: one or more random access response messages, and wherein the method further comprises processing the at least one of the one or more random access response messages within the random access response time window.
7. The method of claim 6 , wherein a format of the at least one of the one or more random access response messages is specific to the request for the other-SI.
8. The method of claim 1 , further comprising initiating a power ramping of the random access preamble in the one or more retransmissions.
9. The method of claim 1 , further comprising initiating the one or more retransmissions of the RACH signal upon at least one of: no response to the RACH signal being detected in the predetermined period of time; or a limit of a preamble counter associated with the RACH signal not being reached.
10. The method of claim 1 , wherein the message that includes the minimum SI is at least one of: a random access response message that corresponds to the random access preamble of the RACH signal, or a random access response message that does not correspond to the random access preamble of the RACH signal.
11. The method of claim 1 , wherein at least one of the one or more retransmissions have been initiated, the method further comprises:
ceasing an initiation of any further retransmissions of the one or more retransmissions upon:
a detection of the message that includes the minimum SI; and
a determination that the requested other-SI is included in the detected message that includes the minimum SI.
12. 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 other system information (other-SI) from the communication network;
initiate the request for the other-SI from the communication network as part of a Radom Access Channel (RACH) procedure; and
a transceiver, the transceiver configured at least to:
transmit a RACH signal, the RACH signal including the request for the other-SI in a random access preamble of the RACH signal, the processor being further configured to:
monitor for a message that includes a minimum SI from the communication network for a predetermined period of time following the transmission of the RACH signal;
determine if the requested other-SI is included in the message that includes the minimum SI upon a detection of the message that includes the minimum SI; and
initiate one or more retransmissions of the RACH signal upon at least one of: the message that includes the minimum SI not being detected, or the other-SI is determined to not be included in a detected message that includes the minimum SI.