Resource Management and Quality of Service in 3G

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Resource Management and Quality of Service in 3G
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Introduction

• With the increase of mobile phone users and
  packet-based multimedia services, its natural to
  provide
• More capacity in the mobile network
• Higher bandwidth in the radio link
• Radio access network (RAN)
• Core network

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Introduction (cont.)

• Supporting QoS to meet the needs of the dominant
  data traffic should evolve
• Current infrastructure
• Network services
• End-user applications toward an end-to-end IP
  solution

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Introduction (cont.)

• Three types of 2G digital networks
• GSM
• TDMA
• CDMA
• 2.5G interim data transport standards based on
• user demand
• regulatory conditions (spectrum availability)
• cost (of equipment and spectrum license)

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Introduction (cont.)

• What is 3G?
• Mobile multimedia
• Personal services
• The convergence of digitalization
• Mobility
• The Internet
• New technologies based on global standards

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Introduction (cont.)

• Leading standards of 3G
• Wideband CDMA (W-CDMA)
• International Mobile Telecommunication in 2000
  (IMT-2000)
• Universal Mobile Telecommunications System (UMTS)
• W-CDMA enables maximum speed of 2 Mb/s in static
  mode

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Introduction (cont.)

• Evolution of GSM standards
• Higher data rates using circuit-switched paradigm
  like HSCSD
• GPRS using GSM/TDMA radio interfaces and RAN
  technologies in the core network with SGSN and
  GGSN (Gn is the interface between SGSN and GGSN)
• EDGE increase the throughput per time slot for
  both HSCSD and GPRS, called ECSD and EGPRS

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Introduction (cont.)

• 3G standardization work has been progressing in
  3GPP
• UMTS network architecture is an evolution of
  GSM/GPRS including
• RAN or UMTS terrestrial RAN (UTRAN)
• The circuit-switched domain (CS)
• The packet-switched domain (PS)

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Introduction (cont.)

• UMTS R00 define 2 types of RAN
• GPRS/EDGE radio access network (GERAN)
• Wideband CDMA RAN (UTRAN)
• Both connect to the same packet-switched core
  network (CN) over an Iu interface
• One main object of R00 is to use the same UMTS CN
  for the 2 RAN and possibly connect with other
  types of access networks (e.g., WLAN, BRAN)
• UMTS R99 only support WCDMA , ATM

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Introduction (cont.)

• UMTS QoS model started in 1999
• Based on
• Operation and QoS provisioning needed to be
  possible in the wireless environment
• Usage of the Internet QoS mechanisms ,
  applications, interoperability, and future QoS
  need
• IP real-time traffic, IP multimedia systems and
  applications

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Introduction (cont.)

• Interoperation between the different nodes of the
  UMTS network architec-ture is defined through
  standard
• interfaces
• Uu between UE and UTRAN, based on WCDMA physical
  layers
• Iu between UTRAN and the CN
• Gn between the 3G-SGSN and the GGSN

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Introduction (cont.)

• Resource management and QoS issues in 3G networks
• UMTS QoS architecture and requirements
• QoS challenges in the 3G air interfaces and RANs
• Common core network connects with UTRAN
• Prognosis for the future

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UMTS QoS Architecture and Requirements

• Main goal provide data delivery with appropriate
  end-to-end (E2E) QoS guarantees
• Key elements
• Mapping of E2E service to services
• Traffic classes and associated QoS parameters
• Location of QoS functions
• QoS negotiation
• Multiplexing of flows onto network resources
• An E2E data delivery model

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UMTS QoS Architecture and Requirements (cont.)

• QoS parameters
• Traffic classes
• E2E data delivery model
• Mapping of E2E services to the services provided
  by the network elements of the UMTS

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Layered bearer QoS Service Architecture

• Network bearer service
• describe how a given network provide QoS.
• Defined by
• Signaling protocol
• User plane transport
• QoS management functions

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Layered bearer QoS Service Architecture(cont.)

• E2E bearer service is the composition of the
  services of the different networks
• E2E Bearer service in the UMTS
• The terminal equipment (TE)/MT local bearer
  service
• The external local bearer service
• The UMTS bearer service

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Layered bearer QoS Service Architecture(cont.)

• TE/MT local bearer service
• Enables communication between the different
  components of mobile station (MS)
• The external bearer service
• Connects the UMTS CN and the destination node
  located in an external network
• The UMTS bearer service
• Use radio access bearer service (RAB) and the
  core network bearer service (CNB)

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Layered bearer QoS Service Architecture(cont.)

• RAB
• Provides confidential transport of signaling and
  data between the MT and the CN Iu
• With the QoS by the UMTS bearer service or with
  the default QoS for signaling
• The services is based on the characteristics of
  the radio interface and is maintained for a
  moving MT

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Layered bearer QoS Service Architecture(cont.)

• RAB is realized by
• Radio bearer service the role is to cover all
  the aspects of the radio interface transport
• Iu-bearer service provide the transport between
  UTRAN and CN
• Uses the UTRA frequency-/time-division duplex
  (FDD/TDD) and physical bearer

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Layered bearer QoS Service Architecture(cont.)

• CNB
• Connects the UMTS CN Iu with the CN gateway to
  the external network
• Role to efficiently control and utilize the back
  bone network in order to provide the contracted
  UMTS bearer service
• UMTS packet CN shall support different backbone
  bearer services for a variety of QoS options

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Layered bearer QoS Service Architecture(cont.)

• CN bearer service
• Uses a generic backbone network service
• Backbone network service
• Covers layer1, 2 functionality

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QoS Requirements

• UMTS bearer service components
• Traffic class classifies flows according to
  their real-time needs
• Conversational class
• Streaming class
• Interactive class
• Background

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QoS Requirements (cont.)

• Maximum bit rate peak rate
• Guaranteed bit rate mean rate
• Delivery order
• specifies in-sequence delivery of SDUs or not
• Maximum SDU size
• SDU format information
• A list of the possible exact sizes of SDUs
• Optimize scheduling over the radio interface

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QoS Requirements (cont.)

• SDU error ratio
• Fraction of SDUs lost or detected as error
• Transfer delay
• Maximum delay of 95 distribution delay for all
  delivered SDUs during lifetime of a bearer
  service
• Traffic handling priority
• Relative importance of SDUs using the bearer
  service
• Allocation/retention priority
• Relative importance for allocation and retention
  of resources between bearers

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Convergence to an IP-Based solution

• IP bearer service manager
• control the external IP bearer service
• Uses standard IP mechanisms in which may be
  different from those used within the UMTS and
  have different parameters
• Exist both in the UE and the gateway node
• Mapping function for interworking between
  mechanisms and parameters

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QoS in 3G Air Interfaces

• Internet service need to extent to MTs
• QoS mechanism on 3G air interface
• QoS framework for 3G air interface
• Be flexible for building various services
• Provide a means for effective negotiation between
  the service provider and end user
• Be practical low complexity of implementation
  and low volume of control signaling

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CDMA Air Interface

• CDMA was selected as the preferred technology for
  the air interface
• Existing QoS schemes for the CDMA air interface
  focus on satisfying the needs of specific
  applications
• Real-time hard QoS guarantees
• Non real-time best effort service

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CDMA Air Interface (cont.)

• Class I real-time traffic
• Is supporting using connection-oriented code
  channels
• Class II non-real-time traffic
• Is transmitted in a best-effort manner through a
  transmission-rate request access scheme which
  utilizes the bandwidth left unused by class I
  traffic

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CDMA Air Interface (cont.)

• QoS scheme that is flexible for
• a wide range of services
• practical to implement
• optimized for supporting Internet services
• Service-class-based QoS framework
• Consider a system with 3 classes
• Premium, gold, and silver

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CDMA Air Interface (cont.)

• Each class offers a characteristic performance to
  its customer, defined as group behavior
• Group behavior
• Premium service offer the negotiated bandwidth
  at all times, regardless of congestion,
  interference, or degradation in the channel
  quality
• Gold and silver service has a certain elasticity
  associated with it
• Implemented by power control and spreading control

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CDMA Air Interface (cont.)

• Class-based bandwidth scheduling scheme is used
  to attain differentiated QoS on the CDMA air
  interface
• Achieved by selectively reducing the transmission
  rates of users when congestion on the air
  interface occurs
• Facilitates services negotiation over the air
  interface
• Radio resource allocation framework that
  characterizes the capacity of a CDMA air
  interface is needed

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CDMA Air Interface (cont.)

• Band-width scheduling scheme can effectively
  achieve QoS differentiation (e.g., mean delay)
  for users in different service classess
• 3G operators can define their own
• Set of service classes
• Choose a preferred way for group behavior
• Offer a class-based pricing scheme

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TDMA Air interface

• EGPRS
• 3G wireless networks based on TDMA
• TDMA-based packet-switched radio technology
• An evolved packet-switched GPRS core network
• EDGE to support higher data rate

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TDMA Air interface (cont.)

• 3G EGPRS system using different scheduling
  mechanisms
• Weighted round-robin type schedulers are
  investigated
• Radio-aware packet scheduler at the RAN
• Conventional packet scheduler at the edge of the
  core network
• Incorporation radio link conditions and radio
  resource management into scheduling can improve
  the overall delay performance
• Using multiple time slots assignments to provide
  differentiated services

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QoS in the Radio Access Network

• RAN provides an access platform for MTs to all
  core networks and network services
• Hides all radio-access-technology-dependent and
  mobility functions from the core network
• Transport technology interconnect the network
  elements like BSs and RNCs
• Diverse QoS requirements of the applications
  themselves combined with the requirements imposed
  by advanced radio control function
• require the transport technologies to provide
  differentiated QoS to multiple classes of traffic

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QoS in the Radio Access Network

• WCDMA radio control of delay on UTRAN transport
  network
• For real-time traffic
• Less than 7 ms in the current 3GPP specification
• For non-real-time traffic
• UTRAN transport delay is governed by the radio
  functions
• outer-loop power control
• soft-handoff control

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QoS in the Radio Access Network

• The jitter requirement for UTRAN transport is in
  general should be less than 10 percent of the
  transport delay
• The loss ratio for UTRAN transport should be at
  least one order less than that of air interface
• Real-time mission-critical

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ATM-Based Transport solution

• ATM currently has relatively mature schemes to
  support QoS (UMTS-gtUTRAN)
• Network dimensioning, traffic management, and
  resource management
• Delay requirement for ATM/ALL2 transport should
  not be too stringent
• to avoid poor bandwidth utilization caused by
  packet-scale congestion

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ATM-Based Transport solution

• CPSdeal with the CBR caused by the periodic
  nature of MAC layers of UMTS radio interface
• CPS packet shaping will significantly reduce the
  bandwidth requirement
• Statistical multiplexing

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IP-Based transport solutions

• Motivations for use of IP transport in the RAN
• IP QoS management is approaching maturity
• IP as a network layer protocol is carefully
  designed to be independent of link/physical
  layers
• IP is quickly becoming the basis for
  packetization of voice, data, signaling,
  operation, administration, and management (OAM)
  in the networking world
• 3G core network is IP-based

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IP-Based transport solutions

• Shortcoming
• Delay-insensitive data applications
• IP header overhead is higher than ATM for voice
• be enhanced to provide QoS support including
  delay, jitter, and loss
• Should support real-time signaling transport,
  reliability and security
• Transport efficiency for a qualified IP solution

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IP-Based transport solutions

• RTP
• SigTran
• IntServ
• RSVP
• DiffServ
• MPLs
• IPHC

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QoS in the Core Network

• CN contains a CS and a PS domain
• Use ATM between CN and Iu
• Usage of PVCs will provide load sharing
  capability and redundancy
• IP layer provide Iu network layer services such
  as routing, addressing, load sharing, and
  redundancy

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QoS in the Core Network

• GPRS Tunneling Protocol (GTP)
• GTP allows multiprotocol packets to be tunneled
  through the backbone over the Iu and Gn
  interfaces
• Iu bearer service and CN bearer service provide
  the transport between the UTRAN and the external
  IP backbone
• QoS should be provided, on ATM-based and
  IP-based, such as DiffServ

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conclusions

• All three types of 2G digital networks will
  converge to 3G digital networks
• Future-proofing is enabled by the concept of PDP
  context per PDP address together with a TFT
  concept
• Developing an all-IP solution for 3G networks
  remains the ultimate goal, where QoS will
  decidedly be supported