LONG TERM EVOLUTION LTE ECE 2526 MOBILE COMMUNICATION

LONG TERM EVOLUTION (LTE) ECE 2526 -MOBILE COMMUNICATION Monday, 25 March 2019 1

WHAT IS LTE? 1. LTE stands for Long Term Evolution and it was started as a project in 2004 by the Third Generation Partnership Project (3 GPP). 2. LTE evolved from an earlier 3 GPP system known as the Universal Mobile Telecommunication System (UMTS), 3. UMTS, on the other hand, had evolved from the Global System for Mobile Communications (GSM). 4. LTE is an all IP based network, supporting both IPv 4 and IPv 6 4 th Generation LTE 3 rd Generation CDMA 2000, WCDMA, UMTS 2 nd Generation GSM, DAMPS 1 st Generation AMPS, ETACS 2

MOTIVATION FOR LTE 1. By 2004, there was a rapid increase of mobile data usage and emergence of new applications such as MMOG (Multimedia Online Gaming), mobile TV, Web streaming contents, etc which required high speeds. 2. Long-Term Evolution (LTE) was proposed as a set of standards to support movement from 3 rd to 4 th generation mobile communication. 3

GOALS OF LTE The Goals of LTE were to provide: 1. Higher data rates (300 Mbps peak downlink and 75 Mbps peak uplink) 2. Low latency (Time required to connect to the network or enter power saving states). This is necessary to support gaming and interactive data transfer 3. Packet optimized radio access technology 4. Seamless mobility; and 5. Higher Quality of Service (Qo. S). 4

MILESTONES IN THE DEVELOPMENT OF LTE 2000 - UMTS/WCDMA 2002 - High Speed Downlink Packet Access (HSDPA) 2005 - High Speed Uplink Packet Access (HSUPA) 2007 - MIMO, IP Multimedia Subsystem(IMS) 2004 - Work started on LTE specification 2008 – Specifications finalized and approved with UMTS Release 8 2010 - First deployment 5

LTE SPECIFICATIONS PARAMETER DETAILS Data type All packet switched data (voice and data). No circuit switched elements Peak downlink speed 100 (SISO), 172 (2 x 2 MIMO), 326 (4 x 4 MIMO) Peak uplink speeds (Mbps) 50 (QPSK), 57 (16 QAM), 86 (64 QAM) Channel bandwidths (MHz) 1. 4, 3, 5, 10, 15, 20 Duplex schemes FDD and TDD Mobility 0 - 15 km/h (optimised), 15 - 120 km/h (high performance) Latency Idle to active less than 100 ms Small packets ~10 ms Spectral efficiency Downlink: 3 - 4 times Rel 6 High Speed Downlink Packet Access (HSDPA) Uplink: 2 -3 x Rel 6 High Speed Uplink Packet Access(HSUPA ) Access schemes Orthogonal Frequency Division Multiple Access (OFDMA) -Downlink Frequency Division Multiple Access (SC-FDMA) - Uplink Modulation types supported QPSK, 16 QAM, 64 QAM (Uplink and downlink) 6

COMPARISON OF PERFORMANCE 3 RD & 4 TH GENERATION WCDMA (UMTS) HSPA HSDPA / HSUPA HSPA+ LTE Max downlink 384 kbps speed Max uplink speed 128 kbps 14 Mbps 28 Mbps 100 Mbps 5. 7 Mbps 11 Mbps 50 Mbps Latency round trip time approx 3 GPP releases 150 ms 100 ms 50 ms (max) ~10 ms Rel 99/4 Rel 5 / 6 Rel 7 Rel 8 Approx years of initial roll out 2003 / 4 2005 / 6 HSDPA 2007 / 8 HSUPA 2008 / 9 2009 / 10 Access methodology CDMA OFDMA / SCFDMA 7

LTE HIGH LEVEL ARCHITECTURE The high-level network architecture of LTE is comprised of following three main components: 1. The User Equipment (UE) 2. The Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) 3. The Evolved Packet Core (EPC) Packet Switched 8

E-UTRAN OPERATING FREQUENCY BANDS 9

USER EQUIPMENT 1. The internal architecture of the user equipment for LTE is the same as the one used by UMTS and GSM. 2. The mobile equipment comprised of the following modules: a) Mobile Termination (MT) : This handles all the communication functions. b) Terminal Equipment (TE) : This terminates the data streams. c) Universal Subscriber Identity Module (USIM): Stores user-specific data including user's phone number, home network identity and security keys etc. Similar to 2 G and 3 G. 10

ARCHITECTURE OF E-UTRAN The Evolved UTRAN (E-UTRAN) handles the radio communications between the User Equipment (UE) and the Evolved Packet Core (EPC). Evolved Node B Evolved Packet Core 11

EVOLVED BASE STATION (e. Node. B) 1. The Evolved base stations (e. Node. B or e. NB) controls the mobiles in one or more cells. 2. The base station that is communicating with a mobile is known as its serving e. NB. 12

HOME e. NB 1. Home e. NB (He. NB) is a base station that has been purchased by a user to provide femtocell coverage within the home or enterprise. 2. A home e. NB belongs to a closed subscriber group (CSG) and can only be accessed by mobiles with a USIM that also belongs to the closed subscriber group. 3. The coverage area of a He. NB is called a Femto cell. 13

LTE FEMTO CELLS 1. LTE Femto cells are low power cellular base stations that employ licenced spectrum. 2. They are deployed in residential, enterprise, metropolitan hot spots. 3. They provide excellent user experience through enhanced coverage, performance and location-based services. 14

EVOLVED PACKET CORE (EPC) The Evolved Packet Core (EPC) consists of the following: 1. Mobility Management Entity (MME) 2. Home Subscriber Server (HSS) 3. Packet Data Network Gateway (PGW): 4. Serving Gateway (S-GW): Acts as a router by forwards data between the base station and the P-GW. Public Data Networks 15

FUNCTIONS OF MOBILITY MANAGEMENT ENTITY (MME) • Mobility Management Entity (MME) Controls the high-level operation of the mobile by interpreting signalling messages by using information from the Home Subscriber Server (HSS). 16

HOME SUBSCRIBER SERVER (HSS) 1. Home Subscriber Server (HSS) is a central database that contains information about all the network operator's subscribers. 2. It is an evolved version of the Home Location Register (HLR) in GSM and UMTS. 17

PACKET DATA NETWORK GATEWAY (P-GW) 1. Packet Data Network Gateway (PGW) communicates with the outside world using SGi interface. 2. Each packet data network is identified by an Access Point Name (APN). 3. P-GW has the same role as the GPRS support node (GGSN) in UMTS and GSM. 18

SERVING GATEWAY (S-GW) Serving Gateway (S-GW): Acts as a router by forwards data between the base station and the P-GW. 19

LTE NETWORK ARCHITECTURE - SUMMARY e. Node. B: Manages all radio access functions Radio admission control Scheduling of UL and DL data Scheduling and transmission of paging and system broadcast • IP header compression (PDCP) • Outer-ARQ (RLC) • • Mobility Management Element (MME) • Authentication • Tracking area list management • Idle mode UE reachability • S-GW/PDN-GW selection • Inter core network node signaling for mobility between 2 G/3 G and LTE • Bearer management functions. Serving Gateway (S-GW) • Serving a large number of e. Node. Bs, • focus on scalability and security Policy and Charging Rules Function (PCRF) • Network-wide control of flows: detection, gating, Qo. S and flow-based charging • authorizes network-wide use of Qo. S resources. Packet Data Network (PDN) Gateway • IP anchor point for bearers • UE IP address allocation • Per-user based packet filtering • Connectivity to packet data network

SUMMARY OF FUNCTIONS OF E-UTRAN & EPC 21

LTE NETWORK AREA An LTE network area is divided into three different types of geographical areas, i. e 1. MME Pool Area: Area where a UE can move without a change of serving MME. 2. S-GW Service Area: An area served a serving gateway (S-GW). The UE can move in this area without a change of S-GW. 3. Tracking Area: Smaller areas used to track the locations of mobiles that are on standby mode. Same as a Location Area(LA) in GSM. 22

LTE RADIO PROTOCOL ARCHITECTURE The radio protocol architecture for LTE is made of two main parts, i. e 1. 2. control plane; and user plane. CONTROL PLANE The radio resource control (RRC) protocol writes the signalling messages that are exchanged between the base station (e. Node. Bs) and the UE. USER PLANE The application creates data packets that are processed by protocols such as TCP, UDP and IP 23