192620010 Mobile & Wireless Networking Lecture 6: Cellular - PowerPoint PPT Presentation

192620010 Mobile & Wireless Networking Lecture 6: Cellular Systems (UMTS / LTE) (2/2) & Other systems [Reader, Part 5] [Optional: Schiller, Section 4.2, 4.3, 5, 6] Geert Heijenk Mobile and Wireless Networking 2013 / 2014

Outline of Lecture 6 q Cellular Systems (UMTS / LTE) (2/2) q UMTS High Speed Downlink Packet Access (HSDPA) q UMTS High Speed Uplink Packet Access (HSUPA) q Long Term Evolution (LTE) q Other systems q DECT q TETRA q Satellite Systems 2 Mobile and Wireless Networking 2013 / 2014

HSDPA (The downlink) Main improvements: q MAC-layer: from RNC to base station q Improved radio: higher order modulation initially 16-QAM, newer releases 64 QAM Techniques used: q Fast Adaptive Modulation & Coding q Fast Channel-Dependent Scheduling q Fast Hybrid ARQ Result: q increases throughput ( → 14.4 Mbps) q reduces latency q increases data capacity q newer releases promise throughputs up to 86.4 Mbps (with MIMO, 64-QAM, and multiple carriers (dual-cell)) Introduction: q 2006 (in NL, max 28.8 Mbps (2012)) 3 Mobile and Wireless Networking 2013 / 2014

Fast Channel-Dependent Scheduling Schedule a packet for transmission to a certain user when it has a “good” channel Increases throughput • May decrease fairness between users • à trade-off 4 Mobile and Wireless Networking 2013 / 2014

Example of Fast Channel-Dependent Scheduling Proportional Fair Scheduling: R m ( n ): achievable data rate of user m in the n th slot / subframe T m ( n ): average data rate of user m in the the last t c slots / subframes base station will transmit to user m * in the nth slot / subframe: R m ( n ) m * ( n ) = arg max T m ( n ) m = 1,2,..., M average data rate is updated after each slot / subframe: # (1 ! 1 ) T m ( n ) + (1 m = m * ( n ) ) R m ( n ) % t c t c % T m ( n + 1) = $ (1 ! 1 % m " m * ( n ) ) T m ( n ) % t c & 5 Mobile and Wireless Networking 2013 / 2014

HSUPA (the enhanced uplink) Main improvements: q MAC-layer: from RNC to base station (as HSDPA) l no higher order modulation Techniques used: q Fast Channel-Dependent Scheduling q Fast Hybrid ARQ Result: q increases throughput ( → 5.76 Mbps) q reduces latency q increases data capacity q newer releases promise throughputs up to 23 Mbps (with higher order modulation, and multiple carriers (dual-cell)) Introduction: q 2008 (in NL, max 5.76 Mbps (2012)) 6 Mobile and Wireless Networking 2013 / 2014

Outline of Lecture 6 q Cellular Systems (UMTS / LTE) (2/2) q UMTS High Speed Downlink Packet Access (HSDPA) q UMTS High Speed Uplink Packet Access (HSUPA) q Long Term Evolution (LTE) q Other systems q DECT q TETRA q Satellite Systems 7 Mobile and Wireless Networking 2013 / 2014

Long Term Evolution: Background Evolution of 3G UMTS radio access technology • Supporting (only) (IP) packet-based services • Targets: • Increased data rates ( ê 100 Mbit/s, é 50 Mbit/s) • Increased capacity (3 – 4 x Rel. 6 (HSDPA)) • Improved spectrum efficiency (x3) • Reduced latency: <5 ms RTT, <100ms channel setup, • Reduced cost • Spectrum flexibility • 8 Mobile and Wireless Networking 2013 / 2014

LTE Characteristics Flexible channel bandwidth: • 1.4, 3, 5, 10, 15, 20 MHz • Duplexing: • FDD, TDD, and combined FDD/TDD (half duplex) • Downlink: • OFDMA • Uplink: • Single Carrier FDMA (OFDMA with extra Discrete Fourier Transform) • MIMO: • up to 4x4 in downlink, or multi-user MIMO (down-/uplink) • Hybrid ARQ: • multiple parallel stop-and-wait, with soft combining / incremental • redundancy Max Data Rates: • 75 Mbit/s (uplink), 300 Mbit/s (downlink, with MIMO) • New core network: • Evolved Packet Core (EPC) / Evolved Packet System (EPS) • 9 Mobile and Wireless Networking 2013 / 2014

LTE Resource Blocks • Resource Blocks (RB) is the smallest resource unit that can be assigned to a mobile (2 at a time) • RB lasts 0.5 ms (6 or 7 OFDM symbols) • RB spans over a 180 kHz sub-channel (containing 12 15 kHz subcarriers) • Number of sub-channels depends on channel bandwidth Source: Capozzi, Piro, Grieco, Boggia & Camarda: Downlink Packet Scheduling in LTE Cellular Networks In: IEEE Communications Surveys & Tutorials, Early Access Article, IEEE Xplore, 2012, pp. 1 - 8. � 10 Mobile and Wireless Networking 2013 / 2014

Mobile and Wireless Networking 2013 / 2014

LTE Network Architecture: Evolved Packet System UE: User Equipment eNodeB: evolved Node B MME: Mobility Management Entity HSS: Home Subscriber Server SGW: Serving GateWay PGW: Packet data network GateWay 12 Mobile and Wireless Networking 2013 / 2014

EPS user-plane protocols 13 Mobile and Wireless Networking 2013 / 2014

EPS control-plane protocols 14 Mobile and Wireless Networking 2013 / 2014

Outline of Lecture 6 q Cellular Systems (UMTS / LTE) (2/2) q UMTS High Speed Downlink Packet Access (HSDPA) q UMTS High Speed Uplink Packet Access (HSUPA) q Long Term Evolution (LTE) q Other systems q DECT q TETRA q Satellite Systems 15 Mobile and Wireless Networking 2013 / 2014

Digital Enhanced Cordless Telecommunication (DECT) q DECT (Digital European Cordless Telephone) standardized by ETSI for cordless telephones, renamed for international marketing reasons into „Digital Enhanced Cordless Telecommunication“ q standard describes air interface between base-station and mobile phone q Characteristics q frequency: 1880-1990 MHz q channels: 120 full duplex q duplex mechanism: TDD (Time Division Duplex) with 10 ms frame length q multiplexing scheme: FDMA with 10 carrier frequencies, TDMA with 2x 12 slots q modulation: digital, Gaußian Minimum Shift Key (GMSK) q power: 10 mW average (max. 250 mW) q range: approx. 50 m in buildings, 300 m open space 16 Mobile and Wireless Networking 2013 / 2014

DECT Dynamic Channel Allocation q periodically (< 30s) measure RSSI on all frequency/timeslot combinations q keep list of combinations with least RSSI for setting up new channels q listen to channels with high RSSI to see what is strongest base- station 17 Mobile and Wireless Networking 2013 / 2014

Outline of Lecture 6 q Cellular Systems (UMTS / LTE) (2/2) q UMTS High Speed Downlink Packet Access (HSDPA) q UMTS High Speed Uplink Packet Access (HSUPA) q Long Term Evolution (LTE) q Other systems q DECT q TETRA q Satellite Systems 18 Mobile and Wireless Networking 2013 / 2014

Trunked Radio Systems q many different radio carriers q assign single carrier for a short period to one user/group of users q police, ambulance, rescue teams, taxi service, fleet management q interfaces to public networks, voice and data services q very reliable, fast call setup, local operation 19 Mobile and Wireless Networking 2013 / 2014

TETRA - Terrestrial Trunked Radio q ETSI standard q formerly: Trans European Trunked Radio q offers Voice+Data and Packet Data Optimized service q point-to-point and point-to-multipoint q ad-hoc and infrastructure networks q several frequencies: 380-400 MHz, 410-430 MHz q FDD, DQPSK q group call, broadcast, discrete listening q Netherlands: C2000 project 20 Mobile and Wireless Networking 2013 / 2014

Outline of Lecture 6 q Cellular Systems (UMTS / LTE) (2/2) q UMTS High Speed Downlink Packet Access (HSDPA) q UMTS High Speed Uplink Packet Access (HSUPA) q Long Term Evolution (LTE) q Other systems q DECT q TETRA q Satellite Systems 21 Mobile and Wireless Networking 2013 / 2014

Satellite Basics q elliptical or circular orbits q complete rotation time depends on distance satellite-earth q inclination: angle between orbit and equator q elevation: angle between satellite and horizon q LOS (Line of Sight) to the satellite necessary for connection è high elevation needed, less absorption due to e.g. buildings q Uplink: connection base station - satellite q Downlink: connection satellite - base station q typically separated frequencies for uplink and downlink q transponder used for sending/receiving and shifting of frequencies q transparent transponder: only shift of frequencies q regenerative transponder: additionally signal regeneration 22 Mobile and Wireless Networking 2013 / 2014

Orbits I Four different types of satellite orbits can be identified depending on the shape and diameter of the orbit: q GEO: geostationary orbit, ca. 36000 km above earth surface q LEO (Low Earth Orbit): ca. 500 - 1500 km q MEO (Medium Earth Orbit) or ICO (Intermediate Circular Orbit): ca. 6000 - 20000 km q HEO (Highly Elliptical Orbit) elliptical orbits 23 Mobile and Wireless Networking 2013 / 2014

Orbits II GEO (Inmarsat) HEO MEO (ICO) LEO inner and outer Van (Globalstar, Allen belts Irdium) earth 1000 10000 Van-Allen-Belts: 35768 km ionized particles 2000 - 6000 km and 15000 - 30000 km above earth surface 24 Mobile and Wireless Networking 2013 / 2014