LTE RRM introduction ITRI u DCell demo 20170115

LTE RRM introduction & ITRI u. D-Cell demo 顏鴻傑 資通所 2017/01/15 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 Copyright ITRI 業技術研究院 (Source: LONG TERM EVOLUTION: 3 GPP LTE Radio and Cellular Technology, Auerbach Publications, 2009) 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) receive level q-Rx. Lev. Min. Offset TS 36. 304 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 TS 36. 304 Copyright ITRI 業技術研究院 26

Handover Procedure Copyright ITRI 業技術研究院 27

L 3 Measurement • Measurements configuration • In RRC connection reconfiguration • Each UE may have different config Copyright ITRI 業技術研究院 28

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 condition matched Measurement Report #2 time. To. Trigger report. Interval Measurement Event Report #1 condition matched time. To. Trigger report. Interval report. Amount: r 2 Start point of measurement Measurement Report #2 report. Amount: r 2 Report. Strongdest. Cells Measurement Report #1 report. Interval Measurement Report #2 report. Interval Start point of measurement Measurement Report #3 report. Interval Measurement Report #4 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 29

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 30

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. 31 Copyright ITRI 業技術研究院 31

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 32

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 33

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 34

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 35 Copyright ITRI 業技術研究院 35

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 36 Copyright ITRI 業技術研究院 36

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, … 37 Copyright ITRI 業技術研究院 37

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 38 Copyright ITRI 業技術研究院 38

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 40 Copyright ITRI 業技術研究院 40

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: • enbdsrcrrcinterface Copyright ITRI 業技術研究院 41

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 42

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 43

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 44

Software component (5/5) • Other libraries: – Raw socket wrapper: • enbdsrcdrv – Common & Sys lib: • enbdsrc Copyright ITRI 業技術研究院 45

External interface • RRC interface: – Initialize socket • rrc_sock_init() – Send message to RRC handler • rrc_send() via socket – Receive message from RRC • rrc_receive() RRC – Process message from RRC • rrc_process_lower() – Encode message to be sent to RRC • Ex. rrc_cell_create_Conn. Setup(), … Copyright ITRI 業技術研究院 46

External interface • S 1 AP interface: – Initialize socket • s 1 ap_sock_init() – Send message to MME S 1 AP handler • s 1 ap_send() via socket – Receive message from MME • s 1 ap_receive() MME – Process message from MME • s 1 ap_process_sctp() – Encode message to be sent to MME • Ex. s 1 ap_client_create_Init. Ue. Msg(), … Copyright ITRI 業技術研究院 47

External interface • X 2 AP interface: – Initialize socket • x 2 ap_sock_init() – Send message to MME X 2 AP handler • x 2 ap_send() via socket – Receive message from other e. NB • x 2 ap_receive() – Process message from other e. NB Other e. NB • x 2 ap_process_sctp() – Encode message to be sent to other e. NB • Ex. x 2 ap_peer_create_Ho. Req. Ack(), … Copyright ITRI 業技術研究院 48

Internal interface • RRC handler: – Send message to S 1 AP handler • rrc_ctx_send_s 1 prim() – Send message to X 2 AP handler • rrc_ctx_send_x 2 prim() – Receive internal message • rrc_receive_prim() – Process internal message • rrc_cell_process_rrm() Copyright ITRI 業技術研究院 49

Internal interface • S 1 AP handler: – Send message to RRC handler • s 1 ap_ctx_send_prim() – Receive internal message • s 1 ap_receive_prim() – Process internal message • s 1 ap_client_process_rrm() Copyright ITRI 業技術研究院 50

Internal interface • X 2 AP handler: – Send message to RRC handler • x 2 ap_ctx_send_prim() – Receive internal message • x 2 ap_receive_prim() – Process internal message • x 2 ap_client_process_rrm() Copyright ITRI 業技術研究院 51

RRM procedure in ENBD • • • RAC development RBC development CMC-HO development CMC-Idle development LB development L 2 measurement 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 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 54

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 55

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 56

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 57

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 58

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 59

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 Target e. NB RRM 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 9. RRC_CON_REL_CFM Copyright ITRI 業技術研究院 7. X 2 AP_UE_RELEASE Trigger RBC? 60

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 61

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 62

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 63

ITRI u. D-Cell brochure Copyright ITRI 業技術研究院 64

Specification (1/2) • 3 GPP R 8/R 9 Compliant / FAPI Compliant • PHY L 1 Software on TI 66 xx Series DSP • L 2/L 3/RRM Software on TI 66 xx Series DSP/ARM core u. D-Cell Housing (388 mm x 235 mm x 67 mm) Copyright ITRI 業技術研究院 65

Specification (2/2) Support 20 MHz, TD-LTE Band 40 2 x 2 MIMO Transmit Diversity, Spatial Multiplexing All L 1 Control, Data Physical Channels Maximum Throughput : DL/UL 100 Mbps/ 10 Mbps (w/ TDD Config 3 : 1) • 16 Concurrent UEs always on • Tx power : 24 d. Bm • Power Interface: 12 V DC, Po. E++ • • Copyright ITRI 業技術研究院 66

Interoperability Testing • Commercial LTE Handheld Devices – – – i. Phone 5 S, 6 Plus Handset, i. Pad (Qualcomm LTE Chipset) Foxconn in. Focus Handset (Qualcomm LTE Chipset) ALU Handset (MTK LTE Chipset) HTC Handset (Qualcomm LTE Chipset) Samsung Note 4 (Qualcomm LTE Chipset) • Commercial LTE Dongles – Band. Rich LTE Dongle (Qualcomm LTE Chipset) – Mitra. Star LTE Dongle (Altair LTE Chipset) • Commercial EPCs – NSN (CHT Lab) / Cisco (ITRI Field Trial) Copyright ITRI 業技術研究院 67

Demo Copyright ITRI 業技術研究院 68

E-UTRAN & EPC logical view Internet UE Core Network LTE-Uu UE Small Cell S 1 MME, S-GW & P-GW X 2 Small Cell OS: TI ARM Linux Copyright ITRI 業技術研究院 Application Servers OS: Linux (desktop version) 69

ITRI test environment • EPC: run MME software and configure NAT – WAN IP: 140. 117. XXX. xxx – LAN IP: 10. 101. 131. 254 • Small cell: run L 1/L 2/L 3 and RRM software, ex: IP Cell Identity Carrier frequency: (serving, neighbors) Physical cell ID e. NB #8 e. NB #14 10. 101. 131. 8 10. 101. 131. 14 8 14 2320 MHz, 2350 MHz, 2320 MHz, 8 14 Default gateway 10. 101. 131. 254 MME IP 10. 101. 131. 254 Copyright ITRI 業技術研究院 EARFCN=39150 EARFCN=38850 70

DEMO • UE idle/connected switching: try the commands Steps enbd mmed Command 1 show active UE list: “s” show registered UE list: “s” Command 2 release a active UE: “r ue_id” release all active UE : “r” release a active UE: “r ue_id_mme” Command 3 Copyright ITRI 業技術研究院 do paging of all idle UE: “s 255” do paging of a idle UE: “s ue_id_mme” 72

DEMO • UE (inter-freq) handover: Steps enbd (#6) Command 1 show neighbor list: “s” Command 2 do handover: “s ue_id -h 8” Command 3 Copyright ITRI 業技術研究院 enbd (#8) show neighbor list: “s” do handover: “s ue_id -h 6” 73

DEMO • UE dedicated GBR bearer: Steps mmed Command 1 show registered UE list: “s” Command 2 show EPS bearer info of a UE: “s ue_id” Command 3 add a dedicated EPS bearer (using only remote port# 5001 as the packet filter) where QCI=1, MBR_DL=5000 kbps, MBR_UL=1500 kbps, GBR_DL=1000 kbps, GBR_UL=500 kbps: “add_bc ue_id_mme 5006 1 5000 1500 1000 500” Command 4 show EPS bearer info of a UE: “s ue_id” Command 5 delete a dedicated EPS bearer where beare_ID=6: “del_bc ue_id_mme 6” – Performance test: iperf • Console 1: “iperf -u -c 10. 101. 131. 100 -t 100 -i 1 -b 20 m -p 5001” • Console 2: “iperf -u -c 10. 101. 131. 100 -t 100 -i 1 -b 20 m -p 5006” Copyright ITRI 業技術研究院 74

Thanks for your time. We hope this introduction is helpful. Copyright© 2013 業技術研究院 75