EE5406 Wireless Network Protocols Network Architectures

Transcription

1 EE5406 Wireless Network Protocols Network Architectures Dr. David Wong Tung Chong Website: Academic Year 2010/2011

2 Outline Network Architectures GSM (2G Cellular) GPRS (2G+ Cellular) UMTS (3G Cellular) LTE (3.9G Cellular) LTE Advanced (4G Cellular) IEEE WiMAX WMAN IEEE WLAN IEEE Bluetooth WPAN IEEE Zigbee WPAN ECMA 368 (WiMedia) WPAN IEEE c WPAN ECMA 387 WPAN 2

3 PSTN, PLMN, ISDN MT BTS GSM (2G Cellular) BSS base station subsystem AuC, EIR HLR VLR GMSC BSC BTS BTS MSC BTS MT mobile terminal NSS network and switching subsystem OSS operation and support subsystem BTS base transceiver stations BSC base station controller AuC authentication center EIR equipment identity register HLR home location register VLR visitor location register MSC mobile switching center GMSC gateway MSC PSTN public switched telephone network PLMN public land mobile network ISDN integrated services digital network Figure 1. Global System for Mobile Communications (GSM) Network Architecture BSC BTS NSS BTS MT MT MT MT BSS OSS MT 3

4 GSM (2G Cellular) The GSM system consists of three subsystems Base station subsystem (BSS) Network and switching subsystem (NSS) Operation and support subsystem (OSS) Base station subsystem (BSS) BSS consists of Base transceiver stations (BTSs) Base station controller (BSC) The role of the BSS is to provide transmission paths between the mobiles and the NSS. The BTS is the radio access point. Each BTS serves one cell. The main functions of the BSC are cell management, control of a BTS and exchange functions. 4

5 GSM (2G Cellular) Network and switching subsystem (NSS) NSS includes switching and location management functions. NSS consists of mobile switching center (MSC) home location register (HLR) visitor location register (VLR) gateway MSC (GMSC) authentication center (AuC) equipment identity register (EIR) The MSC is a complete exchange with switching and signaling capabilities. GMSC provides interface between the mobile network and public switched telephone network (PSTN), public land mobile network (PLMN) and integrated services digital network (ISDN). MSC is capable of routing calls from the BTS and BSC to mobile users in the same network (through BSC and BTS) or to users in the PSTN, PLMN and ISDN (through GMSC) or to answering machines integrated within the MSC. 5

6 GSM (2G Cellular) HLR and VLR are databases for location management. The HLR stores the identity and user data of all subscribers belonging to the mobile operator for both local and aboard (roaming) users. The VLR contains the permanent data found in the HLR of the user s original network for all subscribers currently residing in its MSC serving area. That is, VLR contains data of its own subscribers of the network that are in its serving area, as well as that (temporary data) of roamers from other GSM networks. The AuC is related to HLR and contains sets of parameters needed for authentication procedures for the mobile stations. EIR is an optional database that contains numbers of the mobile phone equipments. The purpose of EIR is to prevent usage of stolen mobile stations or to bar malfunctioning equipment. 6

7 GPRS (2G+ Cellular) PSTN, PLMN, ISDN BSS BTS GSM core GMSC MSC/VLR BSC BTS BTS HLR GGSN Internet SGSN IP backbone network GPRS core GGSN Data network BSS base station subsystem MT mobile terminal BTS base transceiver stations HLR home location register VLR visitor location register GMSC gateway mobile switching center PSTN public switched telephone network PLMN public land mobile network ISDN integrated services digital network SGSN serving GPRS support node GGSN gateway GPRS support node MT MT MT MT Figure 2. General Packet Radio System (GPRS) Network Architecture 7

8 GPRS (2G+ Cellular) GPRS is a hardware and software upgrade to the existing GSM system. Two new network nodes are added: Serving GPRS support node (SGSN) Gateway GPRS support node (GGSN) SGSN is responsible for the delivery of packets from/to mobile stations within its service area. Its main tasks are Mobility management: Location management Attachment/detachment Packet routing Logical link management Authentication Charging functions 8

9 GPRS (2G+ Cellular) GGSN acts as an interface between the GPRS packet network and external packet-based networks like the Internet. It converts protocol data packet (PDP) address from the external packet-based networks to the GSM address of the specified user and vice versa. For each session in GPRS, a PDP context to describe the session is created. It describes PDP type (e.g., IPv4) PDP address assigned to the mobile station for that session only Requested quality of service (QoS) profile Address of the GGSN the access node to that packet network There may be several SGSNs or GGSNs. All GPRS support nodes are connected through an IP-based GPRS backbone network. 9

10 GPRS (2G+ Cellular) HLR stores the followings: User profile Current SGSN address PDP address(es) e.g., IP address for communication with Internet MSC/VLR is extended with additional functions that allows coordination between GSM circuit-switched services (e.g., telephony) and GPRS packet-switched services. Packet-switched services Real-time multimedia World Wide Web (WWW) File download Each of these services has different QoS requirements. 10

11 GPRS (2G+ Cellular) GPRS QoS profiles Service precedence High priority Normal priority Low priority Reliability - Transmission characteristics of the GPRS network Loss probability Duplication Misinsertion Handling of corruption of packets Delay Average delay Maximum delay 95% of all transfer Throughput Mean bit rate Maximum bit rate 11

12 GPRS (2G+ Cellular) GPRS has three states for location management: Idle Ready Standby In idle state, the network does not know the location of the mobile station and no PDP context is associated with the station. When the mobile station sends or receives packets, it is in ready state. In this state the network knows which cell the user is in. After being silent for a period of time, mobile station reaches standby state. 12

13 GPRS (2G+ Cellular) To locate a mobile, In standby state a GSM location area is divided into several routing areas (RAs) the network performs paging in the current RA In ready state there is no need for paging In idle state the network is paging all BTSs in the current location of the mobile station GPRS utilizes the same radio access network as GSM. Third generation mobile networks have defined different radio interfaces to provide higher bit rate services to users. 13

14 MT MT MT MT Node B : : Node B Node B : : Node B UTRAN UMTS (3G Cellular) RNC : : RNC MSC/ VLR HLR SGSN GMSC GGSN GGSN Core network CS domain PSTN, PLMN, ISDN PS domain Internet Other data network External networks MT mobile terminal Node B a network component that serves one cell RNC radio network controller HLR home location register VLR visitor location register MSC mobile switching center GMSC gateway MSC CS circuit-switched PS packet-switched PSTN public switched telephone network PLMN public land mobile network ISDN integrated services digital network SGSN serving GPRS support node GGSN gateway GPRS support node UTRAN UMTS Terrestrial Radio Access Network Figure 3. Universal Mobile Telecommunications System (UMTS) Network Architecture 14

15 UMTS (3G Cellular) UMTS s basic architecture is split into two domains: User equipment (UE) domain Infrastructure domain UE is used by users to access UMTS services. It includes identity module and mobile equipment. The mobile equipment performs radio communication with the network and contains applications for the services. The infrastructure domain is further split into two domains: Network access (NA) domain Core network (CN) domain 15

16 UMTS (3G Cellular) The NA domain consists of physical entities (nodes), which manage the radio resources. The CN domain consists of physical entities, which provide support for the features and telecommunication services like call management, mobility management, etc. There are two types of NA: Base station subsystem (BSS) Radio network system (RNS) BSS is the GSM radio access network solution, which is also used by GPRS. BSS consists of the base station controller (BSC) and base transceiver stations (BTSs). Each BTS serves one cell. Usually several BTSs are grouped in a base station and place on a single site. 16

17 UMTS (3G Cellular) For UTRAN, network elements are responsible for Radio resource management Handover management Power control RNS is the network system, which corresponds to the GSM BSS. However, RNS is significantly different from the GSM access operation. RNS consists of the radio network controller (RNC), which controls the radio access nodes called Node B. A Node B is a network component that serves one cell. There are different types of Node B like macrocells, microcells and picocells with different requirements in traffic, coverage and services. 17

18 UMTS (3G Cellular) There are two types of Node B: Node B FDD Node B TDD Node B FDD is planned for wider coverage area (macrocells, microcells). Node B TDD is targeted to hot spot in coverage. The core network consists of two domains: circuit-switched (CS) domain packet-switched (PS) domain These two domains in CN are overlapping in some common elements. CS mode is the GSM mode of operation, while PS mode is supported by GPRS. The entities specific to CS domain are MSC and GMSC. The entities specific to PS domain are GGSN and SGSN. 18

19 UMTS (3G Cellular) There are entities shared by both the CS and PS domains: Home subscriber server (HSS) Authentication center (AuC) Equipment identity register (EIR) Visitor location register (VLR) SMS-support nodes HSS is a master database for a given user with the following information: user identification (numbering, address information) user security information (authentication, authorization) user location information user profile information (to services the user has access) HLRs for CS and PS domains are subsets of HSS. HSS also provides IP multimedia functionality in the core network. Other common entities have similar functions as described for GSM and GPRS. 19

20 MT MT MT MT enode B enode B : : enode B enode B E-UTRAN LTE (3.9G Cellular) Serving GW MME HSS Other Access Types (WLAN, ) PDN GW EPC PCRF IMS P/I/S-CSCF IP network MGW MGCF PSTN External networks MT mobile terminal enode B an evolved network component that serves one cell Serving GW serving gateway MME mobility management entity HSS home subscriber server PDN GW packet data network gateway PCRF policy and charging rules functions EPC evolved packet core WLAN wireless local area network P/I/S-CSCF proxy/interrogating/serving call session control function MGCF media gateway control function MGW media gateway IMS IP multimedia subsystem IP internet protocol PSTN public switched telephone network E-UTRAN Evolved UMTS Terrestrial Radio Access Network Figure 4. Long Term Evolution (LTE) Network Architecture 20

21 LTE (3.9G Cellular) In the evolved UMTS evolution, also known as Evolved Packet System (EPS), the new blocks are the Evolved UTRAN (E-UTRAN), also known as the evolved access network. and the Evolved Packet Core (EPC), also known as the evolved packet core network. E-UTRAN consists of a networks of evolved nodebs (enodebs). There is no centralized controller in E-UTRAN. Thus, the E-UTRAN architecture is known to be flat. The enodebs are normally connected to each other by an interface known as X2. The enodebs are connected to the mobility management entity (MME) by an interface known as S1-MME and to the serving gateway (GW) by an interface known as S1-U. The protocols that is running between the enodebs and the MT (or user equipment (UE)) are known as the Access Stratum (AS) protocols. 21

22 LTE (3.9G Cellular) The E-UTRAN is responsible for all radio-related functions like Radio Resource Management All functions related to the radio bearers Radio bearer control Radio admission control Scheduling Dynamic allocation of resources to UEs in both the uplink and downlink Header Compression Compress IP packet headers Otherwise, significant overhead for small packets such as voice over IP (VoIP) Security Encrypted all data that are sent over the radio interface Connectivity to the EPC This consists of the signalling towards the MME and the bearer path towards the serving GW. 22

23 LTE (3.9G Cellular) The EPC consists of several functional entities Mobility management entity (MME) Serving gateway (GW) Packet data network (PDN) gateway Policy and charging rules function (PCRF) MME In charge of all the control plane functions related to subscriber and session management Security procedures Terminal-to-network session handling Idle terminal location management The MME is connected to the home subscriber server (HSS) through an interface known as S6. HSS is the concatenation of the home location register (HLR) and the authentication center (AuC). HSS supports the database containing all subscription information. 23

24 LTE (3.9G Cellular) Serving GW Termination point of packet data interface towards E-UTRAN Serves as local mobility anchor when UEs move across enodebs Packets are routed through this point for intra E-UTRAN mobility and mobility with other 3GPP technologies such as 2G GSM and 3G UMTS. PDN GW Termination point of packet data interface towards PDN. Anchor point for sessions towards the PDN. Supports policy enforcement features (which apply operatordefined rules for resource allocation and usage) Packet filtering (like deep packet inspection for virus signature detection) Evolved charging support (like per URL charging) URL is an address of a web page on the world wide web (WWW). 24

25 LTE (3.9G Cellular) Policy and charging rule functions (PCRF) Responsible for policy control decision-making and for controlling the flow-based charging functionalities in the PDN GW. Provides QoS authorization of data flow through PDN GW. Ensures user s subscription profile. The IP multimedia subsystem (IMS) is a generic platform offering IP-based multimedia services. The call session control function (CSCF) play a key role in IMS architecture. CSCF has three types Proxy Interrogating Serving CSCF establishes, terminates and modifies IMS sessions. 25

26 LTE (3.9G Cellular) Multimedia gateway control function (MGCF) Supports call control protocol conversion. Supports media gateway (MGW). Supports interrogating CSCF. MGW Responsible for media conversion. Responsible for bearer control. Payload processing (e.g., codec, echo canceller, ). 26

27 MT MT MT MT MT RN LTE Advanced (4G Cellular) enode B enode B HeNode B HeNode B E-UTRAN Serving GW MME HeNB -GW Other Access Types (WLAN, ) HSS PDN GW EPC PCRF P/I/S-CSCF IP network MGW MGCF PSTN External networks Figure 5. Long Term Evolution (LTE) Advanced Network Architecture IMS MT mobile terminal RN relay node enode B an evolved network component that serves one cell HeNodeB an evolved network component that serves one femtocell Serving GW serving gateway MME mobility management entity HSS home subscriber server PDN GW packet data network gateway PCRF policy and charging rules functions EPC evolved packet core WLAN wireless local area network P/I/S-CSCF proxy/interrogating/serving call session control function MGCF media gateway control function MGW media gateway IMS IP multimedia subsystem IP internet protocol PSTN public switched telephone network E-UTRAN Evolved UMTS Terrestrial Radio Access Network 27

28 LTE Advanced (4G Cellular) The E-UTRAN for LTE Advanced can support Home enodeb (HeNodeB) which is also known as a femtocell. HeNodeB are basically enodeb of lower cost for indoor coverage improvement. HeNodeB can be connected to the evolved packet core (ECP) directly or via a HeNodeB gateway (GW) which provides support for a large number of HeNodeBs. The E-UTRAN for LTE Advanced is also considering support of relay nodes and enhanced relaying strategies for increased coverage, higher data rates and better QoS performance and fairness for different users. The EPC is not undergoing major changes from the standardized system and architecture evolution (SAE) project. 28

29 IEEE WiMAX WMAN ASN Wimax BS MHR mode RN PMP mode ASN GW Wimax BSs MS MS MS CSN CSN Other operator CSN Mesh mode MS Internet PSTN 3G BS base station RN relay node MS mobile subscriber/station ASN access services network ASN GW ASN gateway CSN core services network PSTN public switched telephone network PMP point-to-multipoint MHR multi-hop relay MS RN RN RN MS MS MS MS MS MS Figure 6. IEEE WiMAX Wireless Metropolitan Area Network (WMAN) Network Architecture 29

30 IEEE WiMAX WMAN The access services network (ASN) is the access network of WiMAX. ASN provides the interface between the user and the core services network (CSN). ASN Handover Authentication through the proxy authentication, authorization and accounting (AAA) server Radio resource management Interoperability with other ASNs Relay of functionality between CSN and mobile station (MS), e.g., IP address allocation 30

31 IEEE WiMAX WMAN ASN gateway Connection and mobility management. Interservice provider network boundaries through processing of subscriber control and bearer data traffic. Serves as an extensible authentication protocol (EAP) authenticator for subscriber identity. Acts as a remote authentication dial-in user service (RADIUS) client to the operator s AAA servers. CSN Transport, authentication and switching part of the network. Represents the core network in WiMAX. Consists of home agent (HA), AAA system and IP servers (gateways to other networks like Internet, public switched telephone network (PSTN), 3G, etc.) 31

32 IEEE WLAN Infrastructure Mode Extended service set Distribution system IEEE 802.x LAN Portal AP access point STA station LAN local area network Basic service set AP/STA1 Basic service set AP/STA5 STA2 STA3 STA4 STA6 STA7 STA8 Figure 7. IEEE WLAN (Infrastructure Mode) Network Architecture 32

33 IEEE WLAN Infrastructure Mode The smallest building block of a wireless LAN is a basic service set (BSS). BSS consists of a number of stations (STAs) executing the same medium access control (MAC) protocol and competing for access to the same shared wireless medium. A BSS may be isolated or it may be connected to a backbone distribution system (DS) through an access point (AP). The access point functions as a bridge. The MAC protocol may be fully distributed or controlled by a central coordination function housed in the access point. The BSS generally corresponds to a cell. The DS can be a switch, a wired network or a wireless network. The figure above shows the simplest configuration, where each station belongs to a single BSS. That is, each station is within wireless range only of other stations within the same BSS. It is also possible for two BSSs to overlapped geographically, so that a single station could participate in more than one BSS. 33

34 IEEE WLAN Infrastructure Mode Furthermore, the association between a station and a BSS is dynamic. Stations may turn off, come within range, and go out of range. An extended service set (ESS) consists of two or more basic service sets (BSSs) interconnected by a distribution system (DS). Typically, the distribution system is a wired backbone LAN but can be any communications network. The extended service set appears as a single logical LAN to the logical link control (LLC) level. Figure 7 shows the access point (AP) is implemented as part of a station. The AP is the logic within a station that provides access to the DS by providing DS services in addition to acting as a station. A portal is used to integrate the IEEE architecture with a traditional wired LAN (IEEE 802.x). The portal logic is implemented in a device such as a bridge or a router, that is part of the wired LAN, and is attached to the distribution system (DS). 34

35 IEEE WLAN Ad Hoc Mode STA1 STA2 STA4 STA station STA3 Figure 8. IEEE WLAN (Ad Hoc Mode) Network Architecture 35

36 IEEE WLAN Ad Hoc Mode In the ad hoc network architecture, stations are connected directly to each other in an ad hoc manner without an AP. This is like a mesh network topology or sometimes known as peer-to-peer network topology. This mode of operation is also known as an independent BSS (IBSS). 36

37 IEEE WLAN Wireless Mesh Mode Extended service set B S S Distribution system IEEE 802.x LAN Portal AP/STA5 AP access point STA station LAN local area network BSS basic service set STA2 STA3 STA4 B S S AP/ STA 9 B S S AP/ STA 12 STA6 STA7 STA8 B S S STA 10 STA11 STA 13 STA14 Figure 9. IEEE WLAN (Wireless Mesh Mode) Network Architecture 37

38 IEEE WLAN Wireless Mesh Mode In the wireless mesh network topology, the distribution system can be a wireless mesh network among the access points. 38

39 IEEE Bluetooth WPAN Wired LAN Bluetooth piconet PSTN Cellular Network AP access point STA station LAN local area network PSTN public switched telephone network BTS base transceiver station BTS Figure 10. Bluetooth Network Architecture 39

40 IEEE Bluetooth WPAN Bluetooth can be used to connect different devices like mobile phone, printer, walkman, etc., to a laptop in a small personal area network called a piconet. The laptop can be connected to the LAN via an access point. A mobile phone can also be connected to a base station in a cellular network which in turn is connected to a PSTN. 40

41 IEEE Zigbee WPAN PANC Personal area network coordinator PANC Full-function device (FFD) PANC Reduced-function device (RFD) (a) (b) Figure 11. IEEE Zigbee Network Topologies (a) star; (b) peer-to-peer 41

42 IEEE Zigbee WPAN The PAN coordinator is the principal controller of a PAN. PANC is a full-function device (FFD). PANC can initiate a communication, terminate the communication and route it around the network. An IEEE network has exactly one PANC. An FFD can connect to both FFDs and reduced-function devices (RFDs). A RFD can connect to only a FFD. Simple applications of a RFD are a light sensor and a lighting controller. A FFD can take up roles of a coordinator and a router. 42

43 ECMA 368 (WiMedia) WPAN Wired LAN AP access point STA station PSTN LAN local area network PSTN public switched telephone network ECMA 368 piconet PNC Cellular Network BTS base transceiver station PNC piconet coordinator BTS Figure 12. ECMA 368 Network Architecture 43

44 ECMA 368 (WiMedia) WPAN WiMedia can be used to connect different devices like mobile phone, printer, storage device, MP3/4 player, etc., to a laptop in a small wireless personal area network (WPAN) such as a piconet as known in Bluetooth. A WPAN for WiMedia is shown in Figure 12. The connectivity between the laptop and the devices can be done using Wireless USB. Wireless USB makes use of a type of reservation known as Private Distributed Reservation Protocol in WiMedia medium access control. The laptop can be connected to the local area network (LAN) via an access point. A mobile phone can also be connected to a base station in a cellular network which in turn is connected to a public switched telephone network (PSTN). This example shows a star topology but WiMedia does not need to be in this topology only. As it has a distributed medium access control, WiMedia can have other topologies, e.g., those with mesh-connectivity. 44

45 IEEE c WPAN Wired LAN IEEE c piconet PNC PSTN Cellular Network AP access point STA station LAN local area network PSTN public switched telephone network BTS base transceiver station PNC piconet coordinator HDTV BTS Figure 13. IEEE c Network Architecture 45

46 IEEE c WPAN The PHY specifies three modes and one common mode. The three PHY modes are as follows: Single carrier (SC) mode optimized for low power and low complexity. High-speed interface (HSI) mode optimized for low-latency bidirectional data transfer. Audio/video (AV) mode optimized for the delivery of uncompressed, high-definition video and audio. Also defined as a part of the alternate PHY is commonmode signaling, which is a PHY mode that allows devices using different PHY modes to communicate. 46

47 ECMA 387 WPAN Wired LAN AP access point STA station LAN local area network PNC piconet coordinator HDTV high definition television ECMA 387 piconet PNC HDTV HDTV HDTV B A A A A B B B B HDTV (a) A A (b) Figure 14. ECMA 387 Network Topologies (a) star; (b) mesh (types A and B devices) 47

48 ECMA 387 WPAN The standard provides high rate wireless personal area network (including point-to-point) transport for both bulk data transfer and multimedia streaming. The key usage cases and applications are: High definition (uncompressed / lightly compressed) AV streaming Wireless docking station Short Range Sync & Go. The standard defines two device types that interoperate with their own types independently and that can coexist and interoperate with the other types. Thus, it offers a heterogeneous network solution that provides interoperability between all device types. 48

49 ECMA 387 WPAN The two device types are defined as follows: A type A device offers video streaming and WPAN applications in 10- meter range line-of-sight (LOS)/non-line-of-sight (NLOS) multipath environments. It uses high gain trainable antennas. This device type is considered as the high end - high performance device. A second type B device offers video and data applications over shorter range (1-3 meters) point-to-point LOS links with non-trainable antennas. It is considered as the economy device and trades off range and NLOS performance in favour of low cost implementation and low power consumption. 49

50 References David Tung Chong Wong, Peng-Yong Kong, Ying-Chang Liang, Kee Chaing Chua and Jon W. Mark, Wireless Broadband Networks, John Wiley and Sons, Yang Xiao and Yi Pan (Editors), Emerging Wireless LANs, Wireless PANs, and Wireless MANs, John Wiley and Sons, P. Lescuyer and T. Lucidarme, Evolved Packet System (EPS), John Wiley and Sons, Stefania Sesia, Issam Toufik and Matthew Baker, LTE The UMTS Long Term Evolution: from Theory to Practice, John Wiley and Sons, Yan Zhang (Editor), WiMax Network Planning and Optimization, CRC Press, Tony Janevski, Traffic Analysis and Design of Wireless IP Networks, Artech House, William Stallings, Wireless Communications and Networks, Prentice Hall, Amjad Umar, Mobile Computing and Wireless Communications, NGE Solutions, Ecma/TC48/2010/025 (Rev June 2010), ECMA-387 2nd Edition: High Rate 60GHz PHY, MAC and HDMI PAL Whitepaper, June