Method for low layer inter-cell mobility management

1. A serving base station (BS), comprising:

a transceiver configured to transmit and receive wireless communications; and

a processor, coupled to the transceiver, configured to:

determine Synchronization Signal Block (SSB) or Channel-State Information-Reference Signal (CSI-RS) measurements to be performed on a neighboring cell as a Channel Measurement Resource (CMR) in a reportConfig;

transmit, using the transceiver, the reportConfig to a user equipment (UE);

collect data comprising a physical cell ID of the neighboring cell based at least on the reportConfig;

configure N groups of Transmission Configuration Indication (TCI) states for the UE, wherein a first group of the N groups corresponds to a serving BS cell and a second group of the N groups corresponds to the physical cell ID of the neighboring cell;

decide to perform a handover based at least on the data; and

perform the handover from a first TCI state of the first group to a second TCI state of the second group.

2. The serving BS of claim 1 , wherein to collect the data, the processor is further configured to:

trigger a layer 3 (L3) results report; and

receive the L3 results report from the UE via an Uplink Control Information (UCI) signal, wherein the L3 results report comprises: a L3-Reference Signal Received Power (RSRP), a L3-Reference Signal Received Quality (RSRQ), or a L3-Signal to Noise & Interference Ratio (SINR).

3. The serving BS of claim 2 , wherein to trigger the L3 results report, the processor is configured to:

use Radio Resource Control (RRC) signaling, Media Access Control (MAC) Control Element (CE) signaling, or Downlink Control Information (DCI) signaling.

4. The serving BS of claim 2 , wherein the UCI signal comprises a Physical Uplink Control Channel (PUCCH) signal or a Physical Uplink Shared Channel (PUSCH) signal.

5. The serving BS of claim 1 , wherein the processor is further configured to:

determine an event that triggers an event-based report;

reserve a resource in a Physical Uplink Control Channel (PUCCH) signal or a Physical Uplink Shared Channel (PUSCH) signal that enables the UE to provide the event-based report; and

transmit, using the transceiver, the event that triggers the event-based report and the reserved resource to the UE.

6. The serving BS of claim 5 , wherein the processor is further configured to:

receive the event-based report from the UE via an Uplink Control Information (UCI) signal, wherein the event-based report comprises: a layer 3 (L3)-Reference Signal Received Power (RSRP), a L3-Reference Signal Received Quality (RSRQ), or a L3-Signal to Noise & Interference Ratio (SINR).

7. The serving BS of claim 1 , wherein the processor is further configured to:

trigger a layer 1 (L1) results report; and

receive the L1 results report from the UE via an Uplink Control Information (UCI) signal, wherein the L1 results report comprises: a L1-Reference Signal Received Power (RSRP), a L1-Reference Signal Received Quality (RSRQ), or a L1 Signal to Noise & Interference Ratio (SINR).

8. The serving BS of claim 7 , wherein the processor is further configured to:

receive an indication of whether the L1 results report is received from a same downlink reception beam as a previous L1 results report;

determine based on the indication that the L1 results report is from the same downlink reception beam as the previous L1 results report;

perform layer 3 (L3) filtering based on the previous L1 results report and the L1 results report; and

configure the N groups of TCI states based at least on a result of the L3 filtering, and wherein the decision to perform the handover is based at least on the result of the L3 filtering.

9. The serving BS of claim 7 , wherein the processor is further configured to:

receive an indication of whether the L1 results report is received from a same downlink reception beam as a previous L1 results report;

determine based on the indication that the L1 results report is from a different downlink reception beam than the previous L1 results report;

perform layer 3 (L3) filtering on the L1 results report; and

configure the N groups of TCI states based at least on a result of the L3 filtering, and wherein the decision to perform the handover is based at least on the result of the L3 filtering.

10. The serving BS of claim 1 , wherein to perform the handover, the processor is configured to:

use a Media Access Control (MAC) Control Element (CE) to switch from the first TCI state to the second TCI state.

11. The serving BS of claim 1 , wherein to perform the handover, the processor is configured to:

use a Downlink Control Information (DCI) signal to switch from the first TCI state to the second TCI state, wherein the DCI signal comprises a downlink assignment, an uplink grant, or a dedicated DCI format.

12. A user equipment (UE), comprising:

a transceiver configured to transmit and receive wireless communications; and

a processor, coupled to the transceiver, configured to:

receive instructions from a serving base station (BS) to report measurements;

transmit, using the transceiver, a report based on the instructions to the serving BS;

subsequent to transmitting the report, receive from the serving BS via a Media Access Control (MAC) Control Element (CE) or a Downlink Control Information (DCI) signal, a new Transmission Configuration Indication (TCI) state of a neighboring cell; and

switch from a TCI state of a serving BS cell to the new TCI state; and

communicate, using the transceiver, with the neighboring cell via the new TCI state.

13. The UE of claim 12 , wherein the instructions comprise a request for a layer 3 (L3) results report, the processor is configured to:

transmit, using the transceiver, the L3 results report via a Physical Uplink Control Channel (PUCCH) signal or a Physical Uplink Shared Channel (PUSCH) signal.

14. The UE of claim 12 , wherein the instructions comprise an event that triggers an event-based report and a reserved resource, the processor is configured to:

determine that the event is triggered; and

transmit, using the transceiver, the event-based report according to the reserved resource via a Physical Uplink Control Channel (PUCCH) signal or a Physical Uplink Shared Channel (PUSCH) signal.

15. The UE of claim 14 , wherein the processor is further configured to:

determine that the PUCCH signal or the PUSCH signal collides with a second signal;

drop the PUCCH signal or the PUSCH signal; and

subsequently resend the PUCCH signal or the PUSCH signal.

16. The UE of claim 15 , wherein the second signal is: a Physical Random Access Channel (PRACH) signal, a Scheduling Request (SR) signal, or a Hybrid Automatic Repeat Request (HARQ)-ACK signal.

17. The UE of claim 12 , wherein the instructions comprise an event that triggers an event-based report, the processor is configured to:

determine that the event is triggered; and

request a resource by dedicated or normal scheduled request (SR) to transmit the event-based report.

18. The UE of claim 12 , wherein to communicate with the neighboring cell via the new TCI state, the processor is configured to:

start a confirmation timer;

receive a dedicated Physical Downlink Control Channel (PDCCH) from the neighboring cell via the new TCI state;

in response to the PDCCH, stop the confirmation timer; and

apply a new Timing Advance Group (TAG) corresponding to the neighboring cell before transmitting an uplink signal.

19. A method, comprising:

defining, by a serving base station (BS), a reportConfig comprising a physical cell ID of a neighboring cell;

transmitting, by the serving BS, the reportConfig to a user equipment (UE);

receiving, by the serving BS, a results report based on the reportConfig;

grouping, by the serving BS, a first group of Transmission Configuration Indication (TCI) states corresponding to a serving BS cell, and a second group of TCI states corresponding to a neighboring cell, for the UE;

deciding, by the serving BS, to perform a handover based at least on the results report; and

performing, by the serving BS, the handover from a first TCI state of the first group to a second TCI state of the second group.

20. The method of claim 19 , wherein the performing the handover comprises:

using a Media Access Control (MAC) Control Element (CE) or a Downlink Control Information (DCI) signal, to switch from the first TCI state to the second TCI state.