LTE RRM introduction ITRI L 3 RRM SW

LTE RRM introduction & ITRI L 3 -RRM SW 顏鴻傑 資通所 2015/08/25 Copyright ITRI 業技術研究院 1

Outline • RRM concept and key functions • Sample code for RRM development Copyright ITRI 業技術研究院 2

RRM concept and key functions Copyright ITRI 業技術研究院

What’s RRM • Definition: – to allocate and manage the limited radio resource to maximize the system performance and capacity. • Goal: – ensure planned Qo. S of traffic – ensure cell coverage – ensure spectrum utilization Copyright ITRI 業技術研究院 4

LTE features (1/6) • RAN structure – Most of RRM functions are located in e. NB due to lack of the RRM server (a node to do multi-cell RRM) in E-UTRAN. Copyright ITRI 業技術研究院 5

LTE features (2/6) • System bandwidth allocation – E-UTRAN supports 1. 4/3/5/10/20 MHz bandwidths, while UTRAN FDD supports only 5 MHz bandwidth. – RRM is concerned that different bandwidths lead to different available resources and performance in frequency-selective scheduling. Copyright ITRI 業技術研究院 6

LTE features (3/6) • Multiple access techniques – CDMA in UTRAN: both intra-cell and inter-cell UEs may generate interference. – OFDMA/SC-FDMA in downlink/uplink in E-UTRAN: only inter-cell interference. Copyright ITRI 業技術研究院 7

LTE features (4/6) • Multiple antenna techniques – LTE supports many MIMO modes and can dynamical switching among them. – Physical resources in space dimension are different in the MIMO modes. Copyright ITRI 業技術研究院 8

LTE features (5/6) • Optimization of PS domain – No CS domain in LTE. All traffic in PS domain are packets (i. e. , variable length, bursty) and are defined by different parameters compared to CS domain. The parameters of each traffic are determined by many RRM processes. Copyright ITRI 業技術研究院 9

Qo. S Class Identifier (QCI) Copyright ITRI 業技術研究院 10

LTE features (6/6) • Share channel – No dedicated channel in LTE. All traffic share the physical resources which are allocated by packet scheduler. – Specifically, e. NB tells the UE the transmission resources (via control signaling) and takes back them when transmission completed. – Packet scheduler in UMTS is constrained by the dedicated channel design. Copyright ITRI 業技術研究院 11

LTE Interface for RRM Copyright ITRI 業技術研究院 12

RRM key functions (Source: 3 GPP TS 36. 300) Copyright ITRI 業技術研究院 13

Radio Admission Control • RAC purpose: to admit or reject establishment requests for new radio bearers. • RAC goal: to ensure high radio resource utilization by accepting radio bearer requests if radio resources are available. This simultaneously ensures proper Qo. S for inprogress sessions by rejecting radio bearer requests when they cannot be accommodated. Copyright ITRI 業技術研究院 14

RAC process • RAC is triggered when – UE requests serving e. NB to do RRC Connection establishment (i. e. add SRB configuration) – MME requests serving e. NB to do ERAB setup/modification (i. e. add/change DRB configuration such as Qo. S info) – Source e. NB requests target e. NB to do handover preparation (i. e. add SRB and DRB configuration) Copyright ITRI 業技術研究院 15

RAC process • Example: bearer setup (Source: LONG TERM EVOLUTION: 3 GPP LTE Radio and Cellular Technology, Auerbach Publications, 2009) Copyright ITRI 業技術研究院 16

RAC process (Source: LONG TERM EVOLUTION: 3 GPP LTE Radio and Cellular Technology, Auerbach Publications, 2009) Copyright ITRI 業技術研究院 17

Radio Bearer Control • RBC involves the establishment, maintenance and release of radio bearers. • RBC is also concerned with the maintenance of radio bearers of in-progress sessions at the change of the radio resource situation due to mobility and so on. • RBC is involved in the release of radio resources associated with radio bearers including at-session termination and handover. Copyright ITRI 業技術研究院 18

RBC process • When? Copyright ITRI 業技術研究院 19

RBC process Copyright ITRI 業技術研究院 20

RBC 提供 DRA 的 Qo. S 參數 Copyright ITRI 業技術研究院 21

Connection Mobility Control • CMC oversees the management of radio resources related to idle or connected mode mobility. • In connected mode, handover decisions may be based on UE/e. NB measurements, neighbor cell load, traffic distribution, transport, hardware resources, and operator defined policies. Copyright ITRI 業技術研究院 22

CMC process 23 Copyright ITRI 業技術研究院 23

Cell Selection (1/2) • Initial Cell Selection – Scan all RF channels in the E-UTRA bands – Only search for the strongest cell on each carrier frequency – Once a suitable cell is found this cell shall be selected • Stored Information Cell Selection – Stored information of carrier frequencies & optionally also information on cell parameters • Cell Selection when leaving RRC_CONNECTED state – According to redirected. Carrier. Info in RRCConnection. Release if present (left to Redirect topic discusses) Copyright ITRI 業技術研究院 24

Cell Selection (2/2) q-Rx. Lev. Min. Offset receive level q-Rx. Lev. Min max((p-MAX – 23), 0) [d. B] quality q-Qaul. Min-r 9 q-Qaul. Min. Offset-r 9 From PHY after Layer 1 Filtering, -140 ~ -44 [d. Bm] From PHY after Layer 1 Filtering, -19. 5 ~ -3 [d. B] q-Rx. Lev. Min in cell. Selection. Info IE in RRC SIB 1, -70 ~ -22 [d. BM] q-Qual. Min-r 9 in Cell. Selection. Info-v 920 IE in RRC SIB 1, -34 ~ -3 [d. B] Avoid “ping-pong” between different PLMNs q-Rx. Lev. Min. Offset n cell. Selection. Info IE in RRC SIB 1, 1 ~ 8 [d. B] Avoid “ping-pong” between different PLMNs q-Qual. Min. Offset-r 9 in Cell. Selection. Info-v 920 IE in RRC SIB 1, 1 ~ 8 [d. B] p-MAX in RRC SIB 1, -30 ~ 33 [d. Bm] Until now, only 1 UE power class defined, it specifies +23 d. Bm Copyright ITRI 業技術研究院 25

Cell Re-selection Procedure Copyright ITRI 業技術研究院 26

Cell Re-selection (1/7) • Methods to provide cell reselection related information to the UE – System information – RRCConnection. Release message – Inheriting from another RAT at inter-RAT cell (re)selection • Absolute priority – For inter-frequency & inter-RAT frequency cell reselection only Copyright ITRI 業技術研究院 27

• Cell Re-selection (2/7) Step 1. Perform Measurements – Intra-frequency s-Intra. Search. P-r 9 or s-Intra. Search • If serving cell Srxlev > SIntra. Search. P && Squal > SIntra. Search. Q – May not perform intra-freq. measurements • Otherwise – Shall perform intra-freq. measurements – Inter-frequency & Inter-RAT • Inter-freq. or Inter-RAT freq. with higher priority than serving freq. – Shall perform inter-freq. or inter-RAT freq. measurements • Inter-freq. or Inter-RAT freq. with equal or lower priority than serving s-Non. Intra. Search. P-r 9 freq. or s-Non. Intra. Search – If serving cell Srxlev > Snon. Intra. Search. P && Squal > Snon. Intra. Search. Q • May not perform inter-freq. or inter-RAT freq. measurements – Otherwise • Shall perform inter-freq. or inter-RAT freq. measurements Copyright ITRI 業技術研究院 28

• Cell Re-selection (3/7) Step 2. Criteria (1/2) – Higher priority E-UTRAN frequency than serving frequency • If thresh. Serving. Low. Q is present in SIB 3 – A cell fulfils Squal > Thresh. X, High. Q during Treselection. EUTRA – More than 1 second has elapsed since the UE camped on the current serving cell • Otherwise thresh. X-High – A cell fulfils Srxlev > Thresh. X, High. P during Treselection. EUTRA – More than 1 second has elapsed since the UE camped on the current serving cell – Lower priority E-UTRAN frequency than serving frequency • If thresh. Serving. Low. Q is present in SIB 3 – Serving cell fulfils Squal < Thresh. Serving, Low. Q && a cell fulfils Squal > Thresh. X, Low. Q during Treselection. EUTRA – More than 1 second has elapsed since the UE camped on the current serving cell • Otherwise thresh. Serving. Low thresh. X-Low – Serving cell fulfils Srxlev < Thresh. Serving, Low. P && a cell fulfils Srxlev > Thresh. X, Low. P during Treselection. EUTRA – More than 1 second has elapsed since the UE camped on the current serving cell – Equal priority E-UTRAN frequency & Intra-frequency • Fulfilling Criterion S during Treselection. EUTRA • More than 1 second has elapsed since the UE camped on the current serving cell Copyright ITRI 業技術研究院 29

Cell Re-selection (4/7) • Step 2. Criteria (2/2) [d. B] From PHY after Layer 1 Filtering, -140 ~ -44 [d. Bm] From PHY after Layer 1 Filtering, -19. 5 ~ -3 [d. B] q-Rx. Lev. Min in Inter. Freq. Carrier. Freq. Info IE in RRC SIB 5, -70 ~ -22 [d. BM] q-Qual. Min-r 9 in Inter. Freq. Carrier. Freq. Info IE in RRC SIB 5, -34 ~ -3 [d. B] p-MAX in RRC SIB 5, -30 ~ 33 [d. Bm] Until now, only 1 UE power class defined, it specifies +23 d. Bm Copyright ITRI 業技術研究院 30

Cell Re-selection (5/7) • Step 3. Ranking (1/2) Intra-frequency: 0 or q-Offset. Cell Inter-frequency: (q-Offset. Freq + q-Offset. Cell) or q-Offset. Freq From PHY after Layer 1 Filtering, -140 ~ -44 [d. Bm] Copyright ITRI 業技術研究院 31

Cell Re-selection (6/7) • Step 3. Ranking (2/2) t-Reselection. EUTRA in RRC SIB 3 or SIB 5 Copyright ITRI 業技術研究院 32

Handover Procedure Copyright ITRI 業技術研究院 33

L 3 Measurement • Measurements configuration • In RRC connection reconfiguration • Each UE may have different config Copyright ITRI 業技術研究院 34

L 3 Measurement – Trigger Type Event • Event – – – – Event A 1 Event A 2 Event A 3 Event A 4 Event A 5 Event B 1 (Inter RAT) Event B 2 (Inter RAT) • Periodical – Report. Strongest. Cells – Report. CGI Measurement Event Report #1 Report #2 condition matched time. To. Trigger report. Interval report. Amount: r 2 Start point of measurement report. Amount: r 2 Report. Strongdest. Cells Measurement Report #1 Report #2 Report #3 Report #4 report. Interval Start point of measurement report. Interval report. Amount: r 4 Report. CGI Measurement Report Start point of report. Amount: r 1 measurement (always set to r 1) Copyright ITRI 業技術研究院 35

Measurement Report 用途 Event Type 用途 A 1 Serving becomes better than threshold 關閉量測 A 2 Serving becomes worse than threshold 打開量測 A 3 Neighbor becomes offset better than serving Intra/Inter-frequency handover A 4 Neighbor becomes better than threshold Loading balance A 5 Serving becomes worse than threshold 1 and neighbor becomes better than threshold 2 Intra/Inter-frequency handover, Loading balance Copyright ITRI 業技術研究院 36

Handover Type (1) Copyright ITRI 業技術研究院 (2) (1) (2) (3) (4) Intra E-UTRAN HO w/o S-GW relocation Intra E-UTRAN HO with MME/S-GW relocation Inter RAT HO 37

Dynamic Resource Allocation • DRA (or Packet Scheduling, PS) allocates and de-allocates resources including buffering and processing resources and resource blocks to user and control plane packets. 38 Copyright ITRI 業技術研究院 38

DRA jobs NRT: non real-time (a. k. a. non-GBR in LTE) • • • To determine the available radio resources for NRT bearers. To share the available radio resources between NRT bearers. To monitor the allocations for NRT bearers. To monitor the system loading. To perform load control actions for NRT bearers (optional). Copyright ITRI 業技術研究院 39

Basic scheduling policy • Round Robin (RR): – Channel condition is not taken into account. • Max Carrier-to-Interference (C/I) – User with the best channel quality is scheduled. • Proportional Fair (PF) – Short-term channel variations are exploited while maintaining long-term average user data rate. Algorithm Throughput Fairness Complexity Channel tracking Qo. S guarantee low best low no no Max C/I highest bad middle yes PF higher better higher yes RR Copyright ITRI 業技術研究院 40

L 2 Scheduler framework • Protocol stack (per UE/bearer) (DL process) (per TTI, per UE) (scrambled by RNTI) (per PRB, per TTI) Upper scheduler (UL process) Lower scheduler (per TTI, per UE) (scrambled by RNTI) (per PRB, per TTI) (MAC signaling) (Source: LONG TERM EVOLUTION: 3 GPP LTE Radio and Cellular Technology, Auerbach Publications, 2009) Copyright ITRI 業技術研究院 41

Load balancing • Task: to balance traffic load over multiple inter -frequency and inter-RAT cells. • Vertical v. s. horizontal LB: LB among (geographically) overlapped cells LB among neighbor cells 42 Copyright ITRI 業技術研究院 42

Load balancing RAC Overload indication • • 處理 e. NBs 常規性的負載 保持無線資源的高度利用 保證已存在的連線的Qo. S 維持較低的通話遺失率 LB 的主要目的 調整 Handover threshold CMC (Handover) LB 調整 Cell reselection 參數 CMC (Cell reselection) LB 與其他 RRM 模組的關係 43 Copyright ITRI 業技術研究院 43

Load balancing • Intra-LTE considerations: resource utilization, hardware load, transport layer load. • Inter-RAT considerations: available resource, maximum throughput, maximum UE number • other considerations: UE capability, current traffic status, subscriber’s priority, … 44 Copyright ITRI 業技術研究院 44

Inter-Cell Interference Coordination • ICIC manages radio resource blocks to keep inter-cell interference under control, based on the feedback from multiple cells. • Multi-cell RRM approach: to takes into account resources and loads situation in multiple cells 45 Copyright ITRI 業技術研究院 45

Sample code for RRM development – ENBD Copyright ITRI 業技術研究院

ENBD module decomposition RRM Config. & CLI RRC handler X 2 AP handler Serving e. NB (RRC) Neighbor e. NB S 1 AP handler MME User data forward ing Gateway/NAT (raw socket) Serving e. NB (PDCP) Control-plane data User-plane data 47 Copyright ITRI 業技術研究院 47

Software component (1/5) • RRM – Core RRM function development. – Source files: • enbdsrcrrm • RRC handler – Handle interaction of RRM with RRC about cell and UE control procedure. – Source files: • enbdsrcrrc – RRC interface files: • enbdsrcrrcnew Copyright ITRI 業技術研究院 48

Software component (2/5) • S 1 AP handler – Handle interaction of RRM with S 1 AP about cell and UE control procedure. – Source files: • enbdsrcs 1 ap • X 2 AP handler – Handle interaction of RRM with X 2 AP about cell and UE control procedure. – Source files: • enbdsrcx 2 ap Copyright ITRI 業技術研究院 49

Software component (3/5) • User data forwarding – Route user data from PDCP to LAN gateway and vice versa (on a per bearer basis). – Source files: • enbdsrcgtpu • Connection database – Maintain UE and its bearer contexts (shared among all components). – Source files: • enbdsrcconnection Copyright ITRI 業技術研究院 50

Software component (3/5) • Neighbor database – Maintain neighbor cell contexts (shared among all components). – Source files: • enbdsrcnbr • Config & CLI – Config: load software/cell/UE common parameters when ENBD software startup (called by main function). – CLI: implement user input command to dynamic configure parameters or trigger procedures. – Source files: • enbd Copyright ITRI 業技術研究院 *CLI: Command-line interface 51

Software component (5/5) • Other libraries: – Raw socket wrapper: • enbdsrcdrv – Common & Sys lib: • enbdsrc Copyright ITRI 業技術研究院 52

RAC development • Case 1: UE requests serving e. NB to do RRC Connection establishment (i. e. add SRB configuration) RRC UE RRM MME random access RRCConnection. Request 1. RRC_CON_IND RAC RRCConnection. Setup. Complete Copyright ITRI 業技術研究院 2. RRC_CON_SETUP_REQ 3. RRC_CON_SETUP_CFM 4. S 1 AP_INIT_UE_MSG 53

RAC development • Case 1: Call flow (1/2) rrc_receive() rrc_process_lower() rrm_process_prim() prim_Ue. Admission rrm_process_Ue. Admission() 1. RRC_CON_IND rrc_cell_process_Conn. Setup_requested() prim_Ue. Admission rrc_ctx_send_rrmprim() rrc_process_prim() prim_Conn. Setup. Req rrc_cell_process_rrm() rrc_cell_create_Conn. Setup() 2. RRC_CON_SETUP_REQ rrc_send() Copyright ITRI 業技術研究院 54

RAC development • Case 1: Call flow (2/2) rrc_receive() rrc_process_lower() 3. RRC_CON_SETUP_CFM rrc_cell_process_Conn. Setup_confirmed() prim_Init. Conn rrc_ctx_send_s 1 prim() Copyright ITRI 業技術研究院 s 1 ap_receive_prim() prim_Init. Conn s 1 ap_client_process_rrm() s 1 ap_client_create_Init. Ue. Msg() 4. S 1 AP_INIT_UE_MSG s 1 ap_send() 55

RAC development • Case 2: MME requests serving e. NB to do ERAB setup/modification (i. e. add/change DRB configuration such as Qo. S info) UE RRC RRM MME 1. S 1 AP_INIT_CTX_SETUP_REQ RAC + RBC RRCConnection. Reconfiguration 2. RRC_CON_RECONFIG_REQ w/ Meas. Config RRCConnection. Reconfiguration. Complete 3. RRC_CON_RECONFIG_CFM 4. S 1 AP_INIT_CTX_SETUP_RSP Copyright ITRI 業技術研究院 56

RAC development • Case 2: Call flow (1/3) s 1 ap_receive() s 1 ap_process_sctp() rrc_receive() rrc_process_prim() prim_Setup. Conn rrc_cell_process_rrm() 1. S 1 AP_INIT_CTX_SETUP_REQ s 1 ap_client_process_sctp() prim_Setup. Conn s 1 ap_ctx_send_prim() rrc_cell_create_Sec. Actv. Req() 1. 1 RRC_SEC_ACTV_REQ rrc_send() rrc_process_lower() 1. 2 RRC_SEC_ACTV_CFM rrc_cell_process_Sec. Actv_confirmed() prim_Setup. Conn. Ack rrc_cell_create_Ue. Cap. Req() 1. 3 RRC_UE_CAP_REQ rrc_send() Copyright ITRI 業技術研究院 57

RAC development • Case 2: Call flow (2/3) rrm_process_prim() rrc_receive() prim_Add. Drb rrm_process_Add. Bearer() rrc_process_lower() 1. 4 RRC_UE_CAP_CFM rrc_cell_process_Ue. Cap_confirmed() prim_Add. Bearer rrc_process_prim() prim_Add. Drb. Ack rrc_cell_process_rrm() rrc_ctx_send_internal() rrc_cell_create_Conn. Reconfig. Req() 2. RRC_CON_RECONFIG_REQ rrc_send() Copyright ITRI 業技術研究院 58

RAC development • Case 2: Call flow (2/3) rrc_receive() rrc_process_lower() 3. RRC_CON_RECONFIG_CFM rrc_cell_process_Conn. Reconf_confirmed() prim_Setup. Conn. Ack rrc_ctx_send_s 1 prim() Copyright ITRI 業技術研究院 s 1 ap_receive_prim() prim_Setup. Conn. Ack s 1 ap_client_process_rrm() s 1 ap_client_create_Init. Ctx. Setup. Rsp() 4. S 1 AP_INIT_CTX_SETUP_RSP s 1 ap_send() 59

RAC development • Case 3: Source e. NB requests target e. NB to do handover preparation (i. e. add SRB + DRB config) UE RRC Source e. NB 1. X 2 AP_HO_REQ RRM 2. RRC_HO_PREPAR_REQ MME 3. RRC_HO_PREPAR_CFM RAC + RBC 4. RRC_HO_RSV_REQ 5. RRC_HO_RSV_CFM 6. X 2 AP_HO_REQ_ACK RRCConnection. Reconfiguration (Mobility. Info of target cell) RRCConnection. Reconfiguration. Complete 7. RRC_HO_CFM_IND 8. S 1 AP_PS_REQ 9. S 1 AP_PS_RSP 10. RRC_HO_PS_IND Copyright ITRI 業技術研究院 11. X 2 AP_UE_RELEASE 60

RAC development • Case 3: Call flow (1/5) x 2 ap_receive() rrc_process_prim() prim_Setup. Ho. Conn x 2 ap_process_sctp() rrc_cell_process_rrm() 1. X 2 AP_HO_REQ x 2 ap_client_process_sctp() prim_Setup. Ho. Conn x 2 ap_ctx_send_prim() Copyright ITRI 業技術研究院 rrc_cell_create_Ho. Prep. Req() 2. RRC_HO_PREPAR_REQ rrc_send() 61

RAC development • Case 3: Call flow (2/5) rrm_process_prim() rrc_receive() rrc_process_lower() 3. RRC_HO_PREPAR_CFM rrc_cell_process_Ho. Prep_confirmed() prim_Ho. Admission rrm_process_Ho. Admission() rrc_process_prim() prim_Ho. Admission. Ack rrc_cell_process_rrm() rrc_ctx_send_internal() rrc_cell_create_Ho. Rsv. Req() 4. RRC_HO_RSV_REQ rrc_send() Copyright ITRI 業技術研究院 62

RAC development • Case 3: Call flow (3/5) rrc_receive() rrc_process_lower() 5. RRC_HO_RSV_CFM rrc_cell_process_Ho. Rsv_confirmed() prim_Setup. Ho. Conn. Ack rrc_ctx_send_x 2 prim() Copyright ITRI 業技術研究院 x 2 ap_receive_prim() prim_Setup. Ho. Conn. Ack x 2 ap_client_process_rrm() x 2 ap_peer_create_Ho. Req. Ack() 6. X 2 AP_HO_REQ_ACK x 2 ap_send() 63

RAC development • Case 3: Call flow (4/5) rrc_receive() rrc_process_lower() 7. RRC_HO_CFM_IND rrc_cell_process_Ho. Cmp_confirmed() prim_Path. Switch rrc_ctx_send_s 1 prim() Copyright ITRI 業技術研究院 s 1 ap_receive_prim() prim_Path. Switch s 1 ap_client_process_rrm() s 1 ap_client_create_Ps. Req() 8. S 1 AP_PS_REQ s 1 ap_send() 64

RAC development • Case 3: Call flow (5/5) s 1 ap_receive() rrc_process_prim() x 2 ap_receive_prim() prim_Path. Switch. Ack s 1 ap_process_sctp() rrc_cell_process_rrm() prim_Ue. Release x 2 ap_client_process_rrm() 9. S 1 AP_PS_RSP s 1 ap_client_process_sctp() prim_Path. Switch. Ack s 1 ap_ctx_send_prim() rrc_cell_create_Ps. Ind() x 2 ap_peer_create_Ue. Release() 11. X 2 AP_UE_RELEASE 10. RRC_HO_PS_IND x 2 ap_send() rrc_send() prim_Ue. Release rrc_ctx_send_x 2 prim() Copyright ITRI 業技術研究院 65

RBC development • Case 1: MME requests serving e. NB to do ERAB setup (i. e. add DRB configuration such as Qo. S info) UE RRC RRM MME 1. S 1 AP_ERAB_SETUP_REQ RAC + RBC RRCConnection. Reconfiguration 2. RRC_CON_RECONFIG_REQ RRCConnection. Reconfiguration. Complete 3. RRC_CON_RECONFIG_CFM 4. S 1 AP_ERAB_SETUP_RSP Copyright ITRI 業技術研究院 66

RBC development • Case 1: Call flow (1/2) rrm_process_prim() s 1 ap_receive() prim_Add. Drb rrm_process_Add. Bearer() s 1 ap_process_sctp() 1. S 1 AP_ERAB_SETUP_REQ s 1 ap_client_process_sctp() prim_Add. Drb rrc_process_prim() prim_Add. Bearer. Ack rrc_cell_process_rrm() s 1 ap_ctx_send_prim() rrc_cell_create_Conn. Reconfig. Req() 2. RRC_CON_RECONFIG_REQ rrc_send() Copyright ITRI 業技術研究院 67

RBC development • Case 1: Call flow (2/2) rrc_receive() rrc_process_lower() 3. RRC_CON_RECONFIG_CFM rrc_cell_process_Conn. Reconf_confirmed() prim_Add. Bearer. Ack rrc_ctx_send_s 1 prim() Copyright ITRI 業技術研究院 s 1 ap_receive_prim() prim_Add. Bearer. Ack s 1 ap_client_process_rrm() s 1 ap_client_create_Erab. Setup. Rsp() 4. S 1 AP_ERAB_SETUP_RSP s 1 ap_send() 68

RBC development • Case 2: MME requests serving e. NB to do ERAB modify (i. e. change DRB configuration) UE RRC RRM MME 1. S 1 AP_ERAB_MOD_REQ (RAC) + RBC RRCConnection. Reconfiguration 2. RRC_CON_RECONFIG_REQ RRCConnection. Reconfiguration. Complete 3. RRC_CON_RECONFIG_CFM 4. S 1 AP_ERAB_MOD_RSP Copyright ITRI 業技術研究院 69

RBC development • Case 2: Call flow (1/2) rrm_process_prim() s 1 ap_receive() s 1 ap_process_sctp() 1. S 1 AP_ERAB_MOD_REQ s 1 ap_client_process_sctp() prim_Mod. Bearer rrm_process_Modify. Bearer() rrc_process_prim() prim_Mod. Bearer. Ack rrc_cell_process_rrm() s 1 ap_ctx_send_prim() rrc_cell_create_Conn. Reconfig. Req() 2. RRC_CON_RECONFIG_REQ rrc_send() Copyright ITRI 業技術研究院 70

RBC development • Case 2: Call flow (2/2) rrc_receive() rrc_process_lower() 3. RRC_CON_RECONFIG_CFM rrc_cell_process_Conn. Reconf_confirmed() prim_Mod. Bearer. Ack rrc_ctx_send_s 1 prim() Copyright ITRI 業技術研究院 s 1 ap_receive_prim() prim_Mod. Bearer. Ack s 1 ap_client_process_rrm() s 1 ap_client_create_Erab. Mod. Rsp() 4. S 1 AP_ERAB_MOD_RSP s 1 ap_send() 71

RBC development • Case 3: MME requests serving e. NB to do ERAB release (i. e. delete DRB configuration). RBC may adjust other DRBs as well. UE RRC RRM MME 1. S 1 AP_ERAB_REL_CMD RBC RRCConnection. Reconfiguration 2. RRC_CON_RECONFIG_REQ RRCConnection. Reconfiguration. Complete 3. RRC_CON_RECONFIG_CFM 4. S 1 AP_ERAB_REL_RSP Copyright ITRI 業技術研究院 72

RBC development • Case 3: Call flow (1/2) s 1 ap_receive() rrm_process_prim() prim_Rel. Bearer s 1 ap_process_sctp() rrm_process_Release. Bearer() 1. S 1 AP_ERAB_REL_CMD s 1 ap_client_process_sctp() prim_Rel. Bearer s 1 ap_ctx_send_rrmprim() rrc_process_prim() prim_Rel. Bearer. Ack rrc_cell_process_rrm() rrc_cell_create_Conn. Reconfig. Req() 2. RRC_CON_RECONFIG_REQ rrc_send() Copyright ITRI 業技術研究院 73

RBC development • Case 3: Call flow (2/2) rrc_receive() rrc_process_lower() 3. RRC_CON_RECONFIG_CFM rrc_cell_process_Conn. Reconf_confirmed() prim_Rel. Bearer. Ack rrc_ctx_send_s 1 prim() Copyright ITRI 業技術研究院 s 1 ap_receive_prim() prim_Rel. Bearer. Ack s 1 ap_client_process_rrm() s 1 ap_client_create_Erab. Rel. Rsp() 4. S 1 AP_ERAB_REL_RSP s 1 ap_send() 74

CMC-HO development • Part 1: Source e. NB may setup/modify/remove L 3 measurement configurations for the UE dynamically. UE RRC RRM L 3_MEAS 1. RRC_CON_RECONFIG_REQ RRCConnection. Reconfiguration. Complete 2. RRC_CON_RECONFIG_CFM loop Measurement. Report Copyright ITRI 業技術研究院 3. RRC_MEAS_REPORT_IND 75

CMC-HO development • Part 1: Call flow (1/2) rrc_receive() rrm_cmc_evaluate_Meas. Config() rrc_process_lower() rrc_process_prim() 2. RRC_CON_RECONFIG_CFM prim_Meas. Config rrc_cell_process_rrm() rrc_cell_process_Conn. Reconf_confirmed() rrc_cell_create_Conn. Reconfig. Req() 1. RRC_CON_RECONFIG_REQ rrc_send() Copyright ITRI 業技術研究院 76

CMC-HO development • Part 1: Call flow (2/2) rrc_receive() rrc_process_lower() 3. RRC_MEAS_REPORT_IND rrc_cell_process_Conn. Reconf_confirmed() prim_Meas. Report rrc_ctx_send_internal() Copyright ITRI 業技術研究院 77

CMC-HO development • Part 2: Source e. NB make handover decision (i. e. , choose the target cell for the UE to be hand-off). UE RRC RRM Target e. NB HO decision 1. RRC_HO_INFO_REQ 2. RRC_HO_INFO_CFM 5. RRC_HO_CMD_REQ RRCConnection. Reconfiguration 3. X 2 AP_HO_REQ 4. X 2 AP_HO_REQ_ACK (w/ RRCConnection. Reconfiguration) 6. RRC_HO_CMD_CFM RRCConnection. Reconfiguration. Complete 8. RRC_CON_REL_REQ 7. X 2 AP_UE_RELEASE 9. RRC_CON_REL_CFM Copyright ITRI 業技術研究院 78

CMC-HO development • Part 2: Call flow (1/4) rrm_cmc_evaluate_Ho. Config() rrc_process_prim() prim_Ho. Required rrc_cell_process_rrm() rrc_receive() rrc_process_lower() 2. RRC_HO_INFO_CFM rrc_cell_process_Ho. Info_confirmed() prim_Prep. Ho. Conn rrc_cell_create_Ho. Info. Req() rrc_ctx_send_x 2 prim() 1. RRC_HO_INFO_REQ rrc_send() Copyright ITRI 業技術研究院 79

CMC-HO development • Part 2: Call flow (2/4) x 2 ap_receive_prim() x 2 ap_receive() prim_Prep. Ho. Conn x 2 ap_client_process_rrm() x 2 ap_process_sctp() 4. X 2 AP_HO_REQ_ACK x 2 ap_peer_create_Ho. Req() 3. X 2 AP_HO_REQ x 2 ap_send() Copyright ITRI 業技術研究院 x 2 ap_client_process_sctp() prim_Prep. Ho. Conn. Ack x 2 ap_ctx_send_prim() 80

CMC-HO development • Part 2: Call flow (3/4) rrc_process_prim() prim_Prep. Ho. Conn. Ack rrc_cell_process_rrm() rrc_receive() rrc_process_lower() 6. RRC_HO_CMD_CFM rrc_cell_create_Ho. Cmd. Req() 5. RRC_HO_CMD_REQ rrc_send() Copyright ITRI 業技術研究院 rrc_cell_process_Ho. Cmd_confirmed() prim_Prep. Ho. Conn rrc_ctx_send_x 2 prim() 81

CMC-HO development • Part 2: Call flow (4/4) x 2 ap_receive() x 2 ap_process_sctp() 7. X 2 AP_UE_RELEASE x 2 ap_client_process_sctp() prim_Ue. Release x 2 ap_ctx_send_prim() Copyright ITRI 業技術研究院 rrc_receive() rrc_process_prim() rrc_process_lower() prim_Ue. Release 9. RRC_CON_REl_CFM rrc_cell_process_rrm() rrc_cell_process_Conn. Re. L_confirmed() rrc_cell_create_Conn. Rel. Req() 8. RRC_CON_REL_REQ rrc_send() 82

CMC-Idle development • For UE cell reselection: (re-)configure cell broadcast info (i. e. , SIB 3 and SIB 4/SIB 5 parameters). RRC RRM CMC-Idle 1. RRC_SIB 3_CFG_REQ 2. RRC_SIB 3_CFG_CFM option 3. RRC_SIB 4_CFG_REQ 4. RRC_SIB 4_CFG_CFM option 5. RRC_SIB 5_CFG_REQ 6. RRC_SIB 5_CFG_CFM Copyright ITRI 業技術研究院 83

CMC-Idle development • Call flow rrm_cmc_evaluate_Cell. Cofig() rrc_process_prim() prim_Cell. Reconfig rrc_cell_process_rrm() rrc_receive() rrc_process_lower() 2. RRC_SIB 3_CFG_CFM rrc_cell_process_Sib 3_confirmed() rrc_cell_process_Cell. Reconfig_requested() rrm_cell_pack_cell. Setup() 1. RRC_SIB 3_CFG_REQ rrc_send() Copyright ITRI 業技術研究院 84

LB development • load control for idle UE • Configure SIB (similar to CMC-Idle). • load control for connected UE: • Reject lower priority UE/RB during RAC procedure. • Configure CMC-HO threshold. Copyright ITRI 業技術研究院 85

L 2 measurement • e. NB L 2 measurement provisioning • MAC provides cell-level load info to assist LB (and RAC/CMC as well) on demand. RRC RRM RRC_L 2_MEAS_REQ (type=PRB_USAGE, interval=T) RRC_L 2_MEAS_IND Copyright ITRI 業技術研究院 Interval=T 86

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