EE5406 Wireless
Network Protocols –
Network Architectures
Dr. David Wong Tung Chong
Email: [email protected]
Website: http://www1.i2r.a-star.edu.sg/~wongtc/course.html
Outline
• Network Architectures
– GSM (2G Cellular)
– GPRS (2G+ Cellular)
– UMTS (3G Cellular)
– LTE (3.9G Cellular)
– LTE Advanced (4G Cellular)
– IEEE 802.16 WiMAX WMAN
– IEEE 802.11 WLAN
– IEEE 802.15.1 Bluetooth WPAN
– IEEE 802.15.4 Zigbee WPAN
– ECMA 368 (WiMedia) WPAN
– IEEE 802.15.3c WPAN
GSM (2G Cellular)
BSS – base station subsystem 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 PSTN, PLMN, ISDN GMSC MSC AuC, EIR HLR VLR NSS BSC BTS BTS BTS OSS BSC BTS BTS BTS BSS MT MT MT MT MT MT
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.
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.
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.
GPRS (2G+ Cellular)
PSTN, PLMN, ISDN GMSC MSC/VLR HLR GSM core BSC BTS BTS BTS BSS SGSN IP backbone network Internet Data network GGSN GGSN GPRS core MT MTBSS – 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
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
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
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
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
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
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.
PSTN, PLMN, ISDN GMSC MSC/ VLR HLR Core network SGSN Internet Other data network GGSN GGSN CS domain PS domain External networks UTRAN Node B Node B Node B Node B RNC RNC : : : : : : MT MT 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
MT
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
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.
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.
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.
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.
PDN GW Serving GW EPC MME IP network PSTN P/I/S-CSCF PCRF External networks E-UTRAN eNode B eNode B eNode B eNode B : : MT MT 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
HSS MGW MGCF IMS Other Access Types (WLAN,…) MT MT
LTE (3.9G Cellular)
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.
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.
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).
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 operator-defined 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).
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
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.
LTE Advanced (4G Cellular)
PDN GW Serving GW EPC MME IP network PSTN P/I/S-CSCF PCRF External networks E-UTRAN eNode B eNode B HeNode B HeNode B MT MT MT – mobile terminal RN – relay nodeeNode 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
HSS MGW MGCF IMS Other Access Types (WLAN,…) HeNB -GW MT MT MT RN
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
IEEE 802.16 WiMAX WMAN
Internet RN RN RN RN Wimax BS Wimax BSs MS MS MS MS MS MS MS MS MS BS – base station RN – relay node MS – mobile subscriber/station ASN – access servicesnetwork
ASN GW – ASN gateway CSN – core services network PSTN – public switched telephone network PMP – point-to-multipoint MHR – multi-hop relay ASN GW ASN CSN CSN Other operator CSN PSTN 3G MS MS MHR mode Mesh mode PMP mode
IEEE 802.16 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
IEEE 802.16 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.
IEEE 802.11 WLAN –
Infrastructure Mode
Distribution system IEEE 802.x LAN Basic service set AP/STA1 STA2 STA3 STA4 Basic service set AP/STA5 STA6 STA7 STA8 Extended service set PortalFigure 7. IEEE 802.11 WLAN (Infrastructure Mode) Network Architecture
AP – access point STA – station
IEEE 802.11 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.
IEEE 802.11 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 802.11 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).
IEEE 802.11 WLAN – Ad Hoc
Mode
STA2 STA3 STA4 STA1 STA – stationIEEE 802.11 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).
IEEE 802.11 WLAN – Wireless
Mesh Mode
Distribution system IEEE 802.x LAN B S S STA2 STA3 STA4 B S S AP/STA5 STA6 STA7 STA8 Extended service set Portal AP – access point STA – station LAN – local areanetwork BSS – basic service set B S S STA 10 STA11 AP/ STA 9 B S S STA 13 STA14 AP/ STA 12
IEEE 802.11 WLAN – Wireless
Mesh Mode
• In the wireless mesh network topology, the
distribution system can be a wireless mesh
network among the access points.
IEEE 802.15.1 Bluetooth WPAN
Wired LAN Bluetooth piconet BTS PSTN Cellular Network AP – access point STA – stationLAN – local area network PSTN – public switched
telephone network BTS – base transceiver station
IEEE 802.15.1 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
IEEE 802.15.4 Zigbee WPAN
Full-function device (FFD)
Reduced-function device (RFD) PANC – Personal area network
coordinator
(a) (b)
Figure 11. IEEE 802.15.4 Zigbee Network Topologies (a) star; (b) peer-to-peer
PANC
IEEE 802.15.4 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 802.15.4 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.
ECMA 368 (WiMedia) WPAN
Wired LAN ECMA 368 piconet BTS PSTN Cellular Network AP – access point STA – stationLAN – local area network PSTN – public switched
telephone network BTS – base transceiver station PNC – piconet coordinator
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.
IEEE 802.15.3c WPAN
Wired LAN IEEE 802.15.3c piconet BTS PSTN Cellular Network AP – access point STA – stationLAN – local area network PSTN – public switched
telephone network BTS – base transceiver station PNC – piconet coordinator
PNC
IEEE 802.15.3c 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
common-mode signaling, which is a PHY common-mode that allows devices
using different PHY modes to communicate.
ECMA 387 WPAN
ECMA 387 piconet AP – access point STA – stationLAN – local area network PNC – piconet coordinator
HDTV – high definition television
PNC Wired LAN HDTV HDTV HDTV HDTV A A A A B B B B A A B
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.
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.
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, 2009.
• Yang Xiao and Yi Pan (Editors), Emerging Wireless LANs, Wireless PANs, and Wireless MANs, John Wiley and Sons, 2009.
• P. Lescuyer and T. Lucidarme, Evolved Packet System (EPS), John Wiley and Sons, 2008.
• Stefania Sesia, Issam Toufik and Matthew Baker, LTE – The UMTS Long Term Evolution: from Theory to Practice, John Wiley and Sons, 2009.
• Yan Zhang (Editor), WiMax Network Planning and Optimization, CRC Press, 2009.
• Tony Janevski, Traffic Analysis and Design of Wireless IP Networks, Artech House, 2003.
• William Stallings, Wireless Communications and Networks, Prentice Hall, 2002. • Amjad Umar, Mobile Computing and Wireless Communications, NGE Solutions,
2004.
• Ecma/TC48/2010/025 (Rev. 2 – 30 June 2010), ECMA-387 2nd Edition: High Rate 60GHz PHY, MAC and HDMI PAL Whitepaper, June 2010.