Lect 8 Cellular Internet Access 4G LTE.pdf

University of Science & Technology Faculty of Computer Science & Information Technology Department of information for communication and technology Mobile communications & wireless technology_ it 709 4year/sem 7 Tawffeeg Mohammed Tawfeeg 4G LTE Ar...

University of Science & Technology Faculty of Computer Science & Information Technology Department of information for communication and technology Mobile communications & wireless technology_ it 709 4year/sem 7 Tawffeeg Mohammed Tawfeeg 4G LTE Architecture 2  Overview of LTE LTE stands for Long Term Evolution and it was started as a project in 2004 by telecommunication body known as the Third Generation Partnership Project (3GPP). LTE evolved from an earlier 3GPP system known as the Universal Mobile Telecommunication System (UMTS), which in turn evolved from the Global System for Mobile Communications (GSM). 3  Overview of LTE SAE (System Architecture Evolution) is the corresponding evolution of the GPRS/3G packet core network evolution. The term LTE is typically used to represent both LTE and SAE. Even related specifications were formally known as the evolved UMTS terrestrial radio access (E- UTRA) and evolved UMTS terrestrial radio access network (E-UTRAN). First version of LTE was documented in Release 8 of the 3GPP specifications. 4 Why LTE? The rapid increase of mobile data usage and emergence of new applications such as MMOG (Multimedia Online Gaming), mobile TV, Web 2.0, streaming contents have motivated the 3rd Generation Partnership Project (3GPP) to work on the Long-Term Evolution (LTE) on the way towards fourth-generation mobile. 5 LTE Goals The main goal of LTE is to provide a high data rate, low latency and packet optimized radio access technology supporting flexible bandwidth deployments. Same time its network architecture has been designed with the goal to support packet-switched traffic with seamless mobility and great quality of service. 6  Advantages of LTE High throughput: High data rates can be achieved in both downlink as well as uplink. This causes high throughput. Low latency: Time required to connect to the network is in range of a few hundred milliseconds and power saving states can now be entered and exited very quickly. FDD and TDD in the same platform: Frequency Division Duplex (FDD) and Time Division Duplex (TDD), both schemes can be used on same platform. 7  Advantages of LTE Seamless Connection: LTE will also support seamless connection to existing networks such as GSM, CDMA and WCDMA. Plug and play: The user does not have to manually install drivers for the device. Instead system automatically recognizes the device, loads new drivers for the hardware if needed, and begins to work with the newly connected device. Simple architecture: Because of Simple architecture low operating expenditure (OPEX). 8  LTE 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). The evolved packet core communicates with packet data networks in the outside world such as the internet, private corporate networks or the IP multimedia subsystem. 9  LTE Architecture Con, The interfaces between the different parts of the system are denoted Uu, S1 and SGi as shown below: 10  The User Equipment UE The internal architecture of the user equipment for LTE is identical to the one used by UMTS and GSM which is actually Mobile Equipment ME. The mobile equipment comprised of the following important modules: Mobile Termination MT : This handles all the communication functions. Terminal Equipment TE : This terminates the data streams. 11  The User Equipment UE Universal Integrated Circuit Card UICC : This is also known as the SIM card for LTE equipments. It runs an application known as the Universal Subscriber Identity Module USIM. A USIM stores user-specific data very similar to 3G SIM card. This keeps information about the user's phone number, home network identity and security keys etc. 12 The E-UTRAN The access network The architecture of evolved UMTS Terrestrial Radio Access Network E − UTRAN has been illustrated below 13 The E-UTRAN The access network The E-UTRAN handles the radio communications between the mobile and the evolved packet core and just has one component, the evolved base stations, called eNodeB or eNB. Each eNB is a base station that controls the mobiles in one or more cells. The base station that is communicating with a mobile is known as its serving eNB. LTE Mobile communicates with just one base station and one cell at a time. 14 The E-UTRAN The access network There are following two main functions supported by eNB: 1- The eBN sends and receives radio transmissions to all the mobiles using the analogue and digital signal processing functions of the LTE air interface. 2- The eNB controls the low-level operation of all its mobiles, by sending them signalling messages such as handover commands. 15 The E-UTRAN The access network Each eBN connects with the EPC by means of the S1 interface and it can also be connected to nearby base stations by the X2 interface, which is mainly used for signalling and packet forwarding during handover. 16 The Evolved Packet Core EPC (The core network) The architecture of Evolved Packet Core EPC has been illustrated below. 17 The Evolved Packet Core EPC (The core network) Below is a brief description of each of the components shown in the above architecture: The Home Subscriber Server HSS component is a central database that contains information about all the network operator's subscribers. The Packet Data Network PDN Gateway P − GW communicates with the outside world ie. packet data networks PDN, using SGi interface. The PDN gateway has the same role as the GPRS support node GGSN and the serving GPRS support node SGSN with UMTS and GSM. 18 The Evolved Packet Core EPC Con. The Serving gateway S − GW acts as a router, and forwards data between the base station and the PDN gateway. The Mobility Management Entity MME controls the high-level operation of the mobile by means of signalling messages to the Home Subscriber Server HSS. The interface between the serving and PDN gateways is known as S5/S8. This has two slightly different implementations, namely S5 if the two devices are in the same network, and S8 if they are in different networks. 19 Functional split between the E-UTRAN and the EPC Following diagram shows the functional split between the E- UTRAN and the EPC for an LTE network: 20 Thanks for attentions These slides are adapted from Computer Networking: A Top Down Approach Jim Kurose, Keith Ross Addison- Wesley March 2012 21