Narrowband LTE in Machine to Machine Satellite Communication Petri Niemelä School of Electrical Engineering Thesis submitted for examination for the degree of Master of Science in Technology. Espoo 28.5.2018 Thesis supervisor and advisor: Assistant Prof. Jaan Praks aalto university abstract of the school of electrical engineering master’s thesis Author: Petri Niemelä Title: Narrowband LTE in Machine to Machine Satellite Communication Date: 28.5.2018 Language: English Number of pages: 7+60 Department of Electrical Engineering and Automation Professorship: Control, Robotics and Autonomous Systems Supervisor and advisor: Assistant Prof. Jaan Praks Recent trends to wireless Machine-to-Machine (M2M) communication and Internet of Things (IoT) have created a new demand for more efficient low-throughput wireless data connections. Beside the traditional wireless standards, focused on high bandwidth data transfer, has emerged a new generation of Low Power Wide Area Networks (LPWAN) which targets for less power demanding low-throughput devices requiring inexpensive data connections. Recently released NB-IoT (Narrowband IoT) specification extends the existing 4G/LTE standard allowing easily accessible LPWAN cellular connectivity for IoT devices. Narrower bandwidth and lower data rates combined to a simplified air interface make it less resource demanding while still benefiting from the widely spread LTE technology and infrastructure. Applications, such as wide scale sensor or asset tracking networks, can benefit from a global scale network coverage and easily available low-cost user equipment which could be made possible by new narrowband IoT satellite networks. In this thesis, the NB-IoT specification and its applicability for satellite commu- nication is discussed. Primarily, LTE and NB-IoT standards are designed only for terrestrial use. Their utilization in Earth-to-space communication raises new challenges, such as timing and frequency synchronization requirements when uti- lizing Orthogonal Frequency Signal Multiplexing (OFDM) techniques. Many of these challenges can be overcome by specification adaptations and other existing techniques making minimal changes to the standard and allowing extension of the terrestrial cellular networks to global satellite access. Keywords: Machine Type Communication, Internet of Things, Cellular IoT, NB-IoT, LTE, Satellite Communication aalto-yliopisto diplomityön sähkötekniikan korkeakoulu tiivistelmä Tekijä: Petri Niemelä Työn nimi: Kapeankaistan LTE koneiden välisessä satelliittitietoliikenteessä Päivämäärä: 28.5.2018 Kieli: Englanti Sivumäärä: 7+60 Sähkötekniikan ja automaation laitos Professuuri: Säätötekniikka, robotiikka ja autonomiset järjestelmät Työn valvoja ja ohjaaja: Apulaisprof. Jaan Praks Viimeaikaiset kehitystrendit koneiden välisessä kommunikaatiossa (Machine to Machine Communication, M2M) ja esineiden Internet (Internet of Things, IoT) -sovelluksissa ovat luoneet perinteisteisten nopean tiedonsiirron langattomien standardien ohelle uuden sukupolven LPWAN (Low Power Wide Area Networks) -tekniikoita, jotka ovat tarkoitettu pienitehoisille tiedonsiirtoa tarvitseville sovel- luksille. Viimeaikoina yleistynyt NB-IoT standardi laajentaa 4G/LTE standardia mah- dollistaen entistä matalamman virrankulutuksen matkapuhelinyhteydet IoT laitteissa. Kapeampi lähetyskaista ja hitaampi tiedonsiirtonopeus yhdistettynä yksinkertaisempaan ilmarajapintaan mahdollistaa pienemmät resurssivaatimukset saman aikaan hyötyen laajalti levinneistä LTE teknologioista ja olemassa olevasta infrastruktuurista. Useissa sovelluskohteissa, kuten suurissa sensoriverkoissa, voitaisiin hyötyä merkittävästi globaalista kattavuudesta yhdistettynä edullisiin helposti saataviin päätelaitteisiin. Tässä työssä käsitellään NB-IoT standardia ja sen soveltuvuutta satellittitieto- liikenteeseen. LTE ja NB-IoT ovat kehitty maanpääliseen tietoliikenteeseen ja niiden hyödyntäminen avaruuden ja maan välisessä kommunikaatiossa aiheuttaa uusia haasteita esimerkiksi aika- ja taajuussynkronisaatiossa ja OFDM (Orthogo- nal Frequency Signal Multiplexing) -tekniikan hyödyntämisessä. Nämä haasteet voidaan ratkaista soveltamalla spesifikaatiota sekä muilla jo olemassa olevilla tek- niikoilla tehden mahdollisimman vähän muutoksia alkuperäiseen standardiin, ja täten sallien maanpäälisten IoT verkkojen laajenemisen avaruuteen. Avainsanat: Koneiden välinen kommunikaatio, Esineiden Internet, Cellular IoT, NB-IoT, LTE, Satelliittitietoliikenne iv Contents Abstract ii Abstract (in Finnish) iii Contents iv Abbreviations vi 1 Introduction1 1.1 Motivation................................. 1 1.2 Objective of the Thesis.......................... 2 1.3 Structure of the Thesis.......................... 2 2 Internet of Things4 2.1 The Internet of Things -trend...................... 4 2.2 Machine to Machine Communication.................. 5 2.3 Low Power Wide Area Networks..................... 6 2.4 Cellular Internet of Things........................ 9 2.5 Space-Enabled Internet of Things.................... 10 3 Satellite Communication 12 3.1 Background................................ 12 3.2 Challenges................................. 14 3.3 Satellite Broadcast Services....................... 17 3.4 Mobile Satellite Services......................... 18 3.5 Small satellites.............................. 20 4 4th Generation Mobile Cellular Network 21 4.1 LTE specification............................. 21 4.2 Network Architecture........................... 22 4.3 Protocol stack............................... 23 4.4 Air Interface................................ 24 4.4.1 Orthogonal Frequency Division Multiplexing.......... 25 4.4.2 Single-Carrier Frequency Division Multiple Access....... 27 4.4.3 Cyclic Prefixing.......................... 28 4.4.4 Frame and Protocol Structure.................. 29 4.4.5 Random Access.......................... 30 4.5 LTE in Machine to Machine communication.............. 32 5 Narrowband Internet of Things 33 5.1 Background................................ 33 5.2 Deployment................................ 34 5.3 Downlink................................. 35 5.4 Uplink................................... 37 5.5 Scheduling and Medium Access Control................. 40 v 5.6 User Equipment.............................. 41 6 Cellular Machine to Machine Satellite Network 42 6.1 Concept.................................. 42 6.2 Challenges................................. 44 6.3 Cellular Satellite Network........................ 46 6.4 Downlink................................. 47 6.5 Uplink................................... 49 6.6 Ground User Equipment......................... 52 7 Conclusion 53 References 55 vi Abbreviations 3GPP 3rd Generation Partnership Project 4G 4th Generation Mobile Communication Technology AWGN Additive White Gaussian Noise BPSK Binary Phase Shift Keying CIoT Cellular IoT CP Cyclic Prefix dBm Power in decibels (dB) referenced to one milliwatt (mW) DMRS Demodulation Reference Signal DL Downlink DVB-S2 Digital Video Broadcasting - Satellite - Second Generation eNB or eNodeB Evolved Node B, LTE basestation E-UTRA Evolved Universal Terrestrial Radio Access GEO Geostationary Earth Orbit (35 786 kilometers) HARQ Hybrid Automatic Repeat reQuest ICI Inter Carrier Interference IEEE Institute of Electrical and Electronics Engineers IoT Internet of the Things ISI Inter Symbol Interference ITU-R The Radiocommunication sector of the International Telecommunication Union kbps Kilobits per second Ku-band Ku frequency band according to IEEE standard (12 to 18 GHz) LPWAN Low-Power Wide-Area Network LTE Long Term Evolution LTE-A LTE-Advanced LTE-M LTE Category-M specification for Machine Type Communication M2M Machine to Machine MAC Media/Medium Access Control Mbps Megabits per second MTC Machine-Type Communication NAS Non-stratum Access NB-IoT Narrowband Internet of Things NPBCH Narrowband Physical Broadcast Channel NPDSCH Narrowband Physical Downlink Shared Channel NPRACH Narrowband Physical Random Access Channel NPSS Narrowband Primary Synchronization Signal NPUSCH Narrowband Physical Uplink Shared Channel NSSS Narrowband Secondary Synchronization Signal OFDM Orthogonal Frequency-Division Multiplexing OFDMA Orthogonal Frequency-Division Multiple Access PAPR Peak-to-Average Power Ratio PDU Protocol Data Unit PDCP Packet Data Convergence Protocol vii PRB Physical Resource Block PSK Phase Shift Keying QoS Quality of Service QAM Quadrature Amplitude Modulation QPSK Quadrature Phase Shift Keying RRC Radio Resource Control RLC Radio Link Control S-band S frequency band according to IEEE standard (2 to 4 GHz) SC-FDMA Single Carrier Frequency Division Multiple Access TTI Transmission Time Interval UE User Equipment UHF Ultra High Frequency -band (according to IEEE standard 300 - 1000 MHz) UL Uplink UMTS Universal Mobile Telecommunications System 1 Introduction This chapter is an introductory chapter for the general topic, the main concepts and the motivation for the work. The second half of the chapter describes the general objective and the structure of the thesis for guidance. 1.1 Motivation During the last two decades, the worldwide multiplication of connected devices has been driven by the growth of the personal mobile phone market. In urban areas, wireless communication networks have grown larger, offering high throughput connections for data-demanding customers. Recently, this trend has entered a new phase, offering even higher data rate connections to each user and enabling multiple connected devices for various applications. From recent development,