LONG TERM EVOLUTION (LTE) ECE 525E-MOBILE COMMUNICATION Thursday, - PowerPoint PPT Presentation

LONG TERM EVOLUTION (LTE) ECE 525E-MOBILE COMMUNICATION Thursday, 25 April 2019 1

WHAT IS IS LTE? 1. LTE stands for Long Term Evolution and it was 4 th Generation started as a project in 2004 by the Third Generation LTE Partnership Project (3GPP). 2. LTE evolved from an earlier 3GPP system known as 3 rd Generation the Universal Mobile Telecommunication System CDMA2000, WCDMA, UMTS (UMTS), 3. UMTS, on the other hand, had evolved from the 2 nd Generation Global System for Mobile Communications (GSM). GSM, DAMPS 4. LTE is an all IP based network, supporting both IPv4 1 st Generation and IPv6 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 (300Mbps 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 (QoS) . 4

MIL ILESTONES IN 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 (2x2 MIMO), 326 (4x4 MIMO) Peak uplink speeds (Mbps) 50 (QPSK), 57 (16QAM), 86 (64QAM) Channel bandwidths 1.4, 3, 5, 10, 15, 20 (MHz) Duplex schemes FDD and TDD Mobility 0 - 15 km/h (optimised), 15 - 120 km/h (high performance) Latency Idle to active less than 100ms 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, 16QAM, 64QAM (Uplink and downlink) 6

RD & 4 TH TH GENERATION COMPARISON OF PERFORMANCE 3 RD WCDMA HSPA HSPA+ LTE (UMTS) HSDPA / HSUPA Max downlink 384 kbps 14 Mbps 28 Mbps 100Mbps speed Max uplink speed 128 kbps 5.7 Mbps 11 Mbps 50 Mbps Latency round 150 ms 100 ms 50ms (max) ~10 ms trip time approx 3GPP releases Rel 99/4 Rel 5 / 6 Rel 7 Rel 8 Approx years of 2003 / 4 2005 / 6 HSDPA 2008 / 9 2009 / 10 initial roll out 2007 / 8 HSUPA Access OFDMA / SC- CDMA CDMA CDMA methodology FDMA 7

LTE HIG IGH 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 Packet Switched 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 2G and 3G. 10

ARCHITECTURE OF E-UTRAN The E volved UTRAN (E-UTRAN) handles the radio communications between the User Equipment (UE) and the Evolved Packet Core (EPC). E volved N ode B E volved P acket C ore 11

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

HOME eNB 1. Home eNB (HeNB) is a base station that has been purchased by a user to provide femtocell coverage within the home or enterprise. 2. A home eNB 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 HeNB is called a Femto cell . 4. Home eNB therefore resembles a CENTREX in the fixed/wired telephone networks. 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 (E (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 (P- GW): 4. Serving Gateway (S-GW): Acts as a router by forwards data between the base station and the P-GW. P ublic D ata N etworks 15

FUNCTIONS OF MOBILIT ITY MANAGEMENT ENTITY (M (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 (H (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 networks. 17

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

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

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

SUMMARY OF FUNCT CTIONS OF E-UTRAN & EPC Non-Access Stratum (NAS) A set of protocols used to convey non-radio signalling Radio Resource Management between the User (RRM) strategies and algorithms for Equipment (UE) and the controlling parameters such as Mobility Management transmit power, user allocation, Entity (MME) beamforming, data rates, handover criteria, modulation scheme, error coding scheme, etc RB Control Resource Block (RB) allocation (e.g. Universal Frequency Reuse technique). 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 IO PROTOCOL ARCHITECTURE The radio protocol architecture for LTE is made of two main parts, i.e 1. control plane; and 2. user plane. USER PLANE CONTROL PLANE The application creates The radio resource control data packets that are (RRC) protocol writes the processed by protocols signalling messages that are such as TCP, UDP and IP exchanged between the base station (eNodeBs) and the UE. 23