D2D LTE and IoT Cdric Adjih, Inria Indo/French Workshop on D2D fo - PowerPoint PPT Presentation

D2D LTE and IoT Cédric Adjih, Inria Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris

Context & Outline • Inria in CEFIPRA “D2D” project: protocols, multihop wireless networks (MAC, Routing, … ), Internet of Things (IoT) • Objective: identify techniques/algorithms/protocols/ … that could be used for D2D-LTE/5G+ Outline: state of the art of some protocols/methods 1. Background: IoT in cellular context 2. Random Access (Media Access Control, MAC) 3. Routing, Neighbor/Link Discovery "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 2

Background • Cellular network "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 3

Background • D2D Communications (device to device) "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 4

The advent of IoT • 5G+/Internet of Things – dense deployments "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 5

The advent of IoT • Massive Machine Type Communication: – Low volume traffic (1/hour) – Small packets (100 bytes) – Many devices (~10000) – (energy saving) • Uncertainty about transmitters "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 6

Issue: Massive Access • Inefficent to allocate ressource blocks (slots hannel ... C(1,1) C(2,1) C(3,1) C(1,1) C(2,1) C(3,1) C(1,1) 1 in a TDMA schedule) hannel C(1,2) ... C(1,2) C(2,2) C(3,2) C(1,2) C(1,2) C(2,2) C(3,2) 2 • Inefficient to trigger the access procedure to the base station (eNodeB) for every small Ex: Rach Configuration Index 6 packet – Random Access Channel (RACH) Contention-based random access procedure (from [1]) • How about using random access directly? • Addressed by 4.5G/5G proposals • See also [1]: [1] Laya, A., Alonso, L., & Alonso-Zarate, J. (2014). “Is the random access channel of LTE and LTE-A suitable for M2M communications? A survey of alternatives.” IEEE Communications Surveys & Tutorials, 16(1), 4-16. "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 7

2 Random Access Protocols "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 8

Fundamentals: Multiple Access Protocols • Multiple access on shared transmission medium • Fixed assignment • Polling • Reservation and scheduling • Random access • Random Multiple Access (1970+; see [1]) • Access the channel and send the packet: success / collision / idle • Channel Access Algorithms (CAA): - when to access the channel • Conflict Resolution Algorithms (CRA): (see overview in [2]) - when several nodes collides, how to solve collision [1] IEEE Transactions on Information Theory, Issue 2 - March 1985, Special Issue on “Random Access Protocols” [2] Molle & Polyzos, “Conflict Resolution Algorithms and their Performance Analysis”, Research Report, 1993 "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 9

Fundamentals: Aloha, Binary Exponential Backoff • Random access: ALOHA System [1] • 1/(2e) ~ 0.184% at most • Slotted Aloha: • Maximum throughput: e − 1 = 0.3679 From: Lam & Kleinrock 1975 [2] • Stabilizing Aloha: consider events on the channel • Maintain a learning variable S k where each node transmits with probability 1/S k • The k th slot is either: idle, successful transmission, collision • Update S k as S k+1 based on the outcome (for instance add a constant depending on the outcome) • Adaptive backoff algorithms (Binary Exponential Backoff) • E.g.[2]: After the m th collision, defer by time in window K m ; example: K m = 2 m [1] N. Abramson (1970). "The ALOHA System - Another Alternative for Computer Communications” Proc. 1970 Fall Joint Computer Conference. AFIPS Press. [2] Simon S. Lam and L. Kleinrock, “Dynamic Control Schemes for a Packet Switched Multi-Access Broadcast Channel”, NCC, Anaheim, May 1975, AFIPS, Vol. 44, AFIPS Press "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 10

Fundamentals: Tree Protocol (CRA) A,B,C C A,B A,B A B • Standard Tree Protocol (Capetanakis-Tsybakov-Mikhailov tree algorithms, 1978+), • Modified Tree Protocol (Massey 1981, known collisions are avoided) , 0.375 - 0.381 (with bias) "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 11

Fundamentals: CRA Performance • (See textbooks [1], [2], or overview [3]) • First-Come First-Serve - FCFS 0.487(1) • Independently discovered by Gallager [Galla78], Tsybakov and Mikhailov [Tsyba80], and others (G. Ruget and/or J. Pellaumail [Ruget81]) • Deliver packets in First-Come First-Serve Order (good delay) • Variant: 0.487760, Mosely and Humblet 1985 • Protocol bounds: • C ≤ 0.5 for in-order (FCFS) type of access [Panwar, Towsley and Wolf, 1985] • C ≤ 0.505 for any free access algorithm [Mikhailov and Tsybakov, 1985] • C f ≤ 0.568, [Tsybakov and Likhanov, 1987] [1] Bertsekas, D. P., Gallager, R. G., & Humblet, P. (1992). “Data networks” New Jersey: Prentice-Hall International. [2] Kumar A, Manjunath D, Kuri J. “Wireless Networking”. Morgan Kaufmann; 2008 [3] Molle & Polyzos, “Conflict Resolution Algorithms and their Performance Analysis”, Research Report, 1993 "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 12

Fundamentals: Carrier Sense Multiple Access • Carrier Sense Multiple Access (CSMA)/Listen Before Talk (LBT) Packet 1 a From: Kleinrock& Tobagi,1975 [1] Sensed Idle energy • Persistent/non-persistent • CSMA/CD (collision detection) 0 • CSMA/CA (collision avoidance), • Performance [1]: è 1 when a è 0 (with high G) [1] Kleinrock, L., & Tobagi, F. A. ”Packet switching in radio channels: Part I--carrier sense multiple-access modes and their throughput-delay characteristics”. IEEE Transactions on Communications, 23(12), 1400-1416., 1975 [2] “Delay distributions of slotted ALOHA and CSMA”, Y Yang, TSP Yum - IEEE Transactions on Communications 2003 "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 13

Actual Protocols: LoRaWAN • LoRa (Cycleo/Semtech) / LoRaWAN: Sub-Ghz, Low-Power Wide-Area Network (LPWAN) • LoRa Alliance (MAC Features), unlicensed band • Mostly uplink only • Efficient physical layer (up to -137 dBm sensitivity /155 budget) - regional ISM band (EU 868 MHz, 125/250 kHz of channel bandwidth, 250 bps to 50 kbps, 10 channels) • Variant of chirp-spread spectrum (CSS) • Different spreading factors (SF=7 to 12), and coding rates http://www.link-labs.com/what-is-lora/ Ethernet / cellular / … backhaul Network server Gateway Node Node Node Gateway Node Gateway (multichannel LoRa Demodulator) Node Node Node [1] Claire Goursaud, Jean-Marie Gorce. “Dedicated networks for IoT : PHY / MAC state of the art and challenges.” EAI endorsed transactions on Internet of Things, 2015, "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 14

Actual Protocols: LoRaWAN – MAC Layer • Class A (All): RX1 RX2 Transmission • One transmission, RX DL opp. (Aloha type protocol, free choice of freq.) • EU 868: Aloha + <1% duty-cycle limit (alternate: ETSI - LBT AFA) ; EU 433: same • Class B (Beacon): “synchronous network initiated” • Beaconing from the gateways: devices listen for “beacon slot” and “ping slot” beacon beacon beacon “ping” • Class C (Continuous): always on + randomization of slot • Possible control by the network server: indexes (offset) • Duty-cycle, rate, tx-power, repetition rate, channel "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 15

Actual Protocols: Wi-Fi - 802.11- Distributed Coordination Function (DCF) Contention Idealized Window (CW) view Moment of Contention Window, doubled (CW) local packet arrival CSMA with binary exponential backoff Channel View Channel Busy Channel Busy Transmit Transmit ACK No ACK = collision "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 16

Actual Protocols: Wi-Fi - 802.11 Access with priority Ack • Priority, different IFS Channel Busy … • 802.11e (2005): EDCA … • Enhanced Distributed Channel Access • NAV (virtual carrier sensing) and RTS-CTS mechanism, B • For “multi-hop reservation” (MACAW) A RTS . . A B . . C D CTS • Several variants: Data • 802.11 Point Coordination Function “PCF” - Polling (but not part of Wi-Fi Alliance interoperability) ACK • 802.11e: HCCA = HCF [Hybrid Coord. Func.] Controlled Channel Access • 802.11s (mesh): MCCA = MCF [Mesh Coord. Func.] Controlled Channel Access • 802.11ah (Wi-Fi HaLow), sub-Ghz (802.11ac down-clocked by 10): PV1, RAW (Restricted Access Window), TWT (Target Wake Time) [ex: Newracom NRC7191], sectorisation, NDP,... • 802.11ax (~2018+): “color” DCF, increase CCA & ignore packets from other access points. "D2D LTE and IoT" - C. Adjih - Indo/French Workshop on D2D fo 5G/IoT 21 June 2016, Paris - 17