Energy-efficient and RRC state aware radio resource allocation
Techniques of preserving UE and network resources while performing a paging procedure during cell congestion includes a network node informing a UE if the cell to which the UE is attempting to access is too congested to serve the UE. When a gNB, serving a cell, receives a paging request for the gNB to serve a UE, the gNB first performs a pro-active admission control operation to determine whether there are sufficient resources to serve the UE. When there is too much congestion, the gNB may not admit the UE to the cell and sends RAN raging with a paging flag indicating that the gNB will not serve the UE. The UE in response does not trigger a service request, but rather sends an ACK paging over RRC to the gNB, which in turn notifies the AMF of non-service and that the UE is present.
1. A system, comprising:
a Next Generation Node B (gNB);
an access and mobility management function (AMF);
a user equipment (UE) within the wireless network;
at least one processor; and
at least one memory including computer program code;
the at least one memory and the computer program code configured to cause the system at least to:
camp the UE in a cell of the gNB, wherein the UE is in radio resource control (RRC) Idle mode;
process, by the AMF, a notification from the UE concerning incoming downlink data;
trigger, by the AMF, a timer;
receive, by the gNB from the AMF, a first trigger message providing an indication of downlink data and associated service incoming to the wireless network,
wherein the first trigger message is a second paging message,
wherein the first trigger message includes:
assistance information including parameter values to enable the gNB to determine that the gNB is not able to serve the UE, and
protocol data unit session information to enable the gNB to identify the service;
perform, by the gNB, a proactive admission control operation to produce a determination that the gNB does not have enough radio resources to serve the UE, wherein the proactive admission control operation is performed by the gNB in response to receiving the first trigger message,
transmit, by the gNB to the UE, a first paging message providing an indication that the gNB is unable to serve the UE for service which has triggered the first paging message, wherein the UE is in RRC Idle mode,
wherein the first paging message is transmitted in response to the gNB performing the proactive admission control operation,
wherein the first paging message includes:
a first one-bit acknowledgement (ACK) paging flag indicating that the first paging message should not trigger a service request from the UE, and
a second one-bit ACK paging flag configured to indicate that the gNB should avoid escalating the first paging message based on a geographical area of the UE that is not admitted to the gNB, and
wherein an acknowledgment of the first paging message is received by the gNB over a paged cell served by the gNB;
receive, by the gNB from the UE, a random access preamble as part of a random access procedure;
in response to receiving the random access preamble, transmit, by the gNB to the UE, a random access response;
receive, by the gNB from the UE, an acknowledgment of the first paging message, in place of a service request to terminate the random access procedure;
transmit, by the gNB to the AMF, an acknowledgment of the second paging message;
transmit, by the gNB to the AMF, a non-access stratum (NAS) non-delivery message indicating that the gNB is not serving the UE due to insufficient radio resources, wherein the NAS non-delivery message indicates that the UE is present in the paged cell;
increasing, by the AMF, a time period of the timer that is configured to reduce a number of paging message retransmissions, in response to receiving the NAS non-delivery message, wherein the NAS non-delivery message includes a field for reporting, to the AMF, a lack of radio resources and a presence of the UE in the paged cell;
refrain, by the gNB from sending further radio paging messages to cells other than the paged cell and to other radio access nodes; and
limit, by the gNB, the sending of further radio paging messages to other cells based on their location or a neighbor relationship with the paged cell.