Utran Concepts

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utran concepts

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RNC - AN INTRODUCTIONSlide title In CAPITALS 50 pt Slide subtitle 32 pt
RNC - AN INTRODUCTION
Slide title In CAPITALS 50 pt Slide subtitle 32 pt
UTRAN TOPOLOGY
Top right corner for field-mark, customer or partner logotypes. See Best practice for example.
Slide title 40 pt Slide subtitle 24 pt Text 24 pt Bullets level 2-5 20 pt
2008-03-11
Radio Access Network (RAN)
When evolving into the third generation, the mobile access network will use ATM and IP to provide efficient and flexible transport and routing capabilities. Packet switching technologies will also be adapted to support real-time voice traffic all the way up to and including the terminals. An important component of the new mobile networks is the Cello transport platform for access products. Initially optimised for mobile technology, Cello is now being introduced as a switching node for packet transport. Several Ericsson products are being built on this platform, including media gateways, IP routers, Radio Base Stations (RBSs) and Radio Network Controllers (RNCs).
UMTS Radio Access Network (UTRAN)
UMTS Terrestrial RAN (UTRAN) consists of RNCs, RBSs, Radio Access Sub network Operations Support (RANOS) and the Tools for Radio Access Management (TRAM).
The RBS provides radio resources and maintains the radio links to end-user equipment. The main tasks of the RNC are to manage radio access bearers for user data transport to manage and optimise radio network resources and to control mobility.
UTRAN employs two Asynchronous Transfer Mode (ATM) Adaptation Layers (AAL). The new specially designed AAL2 is used for low-delay real-time connections and AAL5 is used for packet-switched connections not sensitive to delays, and for control and network management signaling.
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Slide title 40 pt Slide subtitle 24 pt Text 24 pt Bullets level 2-5 20 pt
2008-03-11
Iub
(NBAP)
Iu Interface between an RNC and Circuit Switched and Packet Switched Core Networks. The interface is used for traffic related signaling. This includes both RANAP control signaling and user data transfer using frame protocols and tunnelling protocols.
Iub Interface between an RNC and an RBS used for traffic related signaling. This includes both NBAP control signaling and user data signaling using frame protocols.
Uu Interface between an RNC and a UE. The layer 1 part of Uu is terminated in the RBS. Layer 2 part is terminated in RNC. Part of layer 3 is terminated in RNC.
Mur Management interface provided by the RNC. It is used for element management and network management. Users of the interface may be a thin client or RANOS.
Mui Management interface provided by the OMINF. OMINF includes functions to support the infrastructure of the Operation and Maintenance network for UTRAN.
Iur This interface is between an RNC and another RNC. The interface is used for user data and control related signaling.The control signaling is done over the RNSAP protocol and the user data transfer is using Frame Protocols
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Slide title 40 pt Slide subtitle 24 pt Text 24 pt Bullets level 2-5 20 pt
2008-03-11
SRNS
Iur
DRNS
UE
Iu-cs
Iu-ps
Each RNS is responsible for the resources of its set of cells.
For each connection between User Equipment and the UTRAN, One RNS is the Serving RNS. When required, Drift RNSs support the Serving RNS by providing radio resources as shown in figure. The role of an RNS (Serving or Drift) is on a per connection basis between a UE and the UTRAN
Controlling RNC: role an RNC can take with respect to a specific set of Node B's
There is only one Controlling RNC for any Node B. The Controlling RNC has the overall control of the logical resources of its node B's.
Radio Network Subsystem: RNS can be either a full UTRAN or only a part of a UTRAN. An RNS offers the allocation and release of specific radio resources to establish means of connection in between an UE and the UTRAN
A Radio Network Subsystem contains one RNC and is responsible for the resources and transmission/reception in a set of cells.
Serving RNS: role an RNS can take with respect to a specific connection between an UE and UTRAN. There is one Serving RNS for each UE that has a connection to UTRAN. The Serving RNS is in charge of the radio connection between a UE and the UTRAN. The Serving RNS terminates the Iu for this UE.
Drift RNS: role an RNS can take with respect to a specific connection between an UE and UTRAN. An RNS that supports the Serving RNS with radio resources when the connection between the UTRAN and the UE need to use cell(s) controlled by this RNS is referred to as Drift RNS.
Slide title In CAPITALS 50 pt Slide subtitle 32 pt
RADIO ACCESS BEARERS
Slide title In CAPITALS 50 pt Slide subtitle 32 pt
A UMTS Bearer is a UMTS service providing an application using the UMTS network with the ability to send and receive data over the UMTS network with a specific Quality of Service (QoS).
Network Services are considered end-to-end, this means from a Terminal Equipment (TE) to another TE. An End-to-End Service may have a certain Quality of Service (QoS) which is provided for the user of a network service. It is the user that decides whether he is satisfied with the provided QoS or not.
To realise a certain network QoS a Bearer Service with clearly defined characteristics and functionality is to be set up from the source to the destination of a service. A bearer service includes all aspects to enable the provision of a contracted QoS. These aspects are among others the control signalling, user plane transport and QoS management functionality.
A Radio Access Bearer (RAB) represents a bearer between the UMTS Core Network Edge Node (SGSN) and the UE. Each Bearer is associated with either the Packet Switched or Circuit Switched domain and provides a specific Quality of Serivce. Quality Of Service in UMTS is divided into four classes, Conversational, Streaming, Interactive and Background and is also characterised by maximum bitrate, guaranteed bitrate, transfer delay, priority, error rate etc.
RNC Concepts - Radio Access Bearer
Slide title In CAPITALS 50 pt Slide subtitle 32 pt
RNC Concepts - Radio Access Bearer
TE
MT
RAN
CN
EDGE
NODE
CN
Gateway
TE
UMTS
Bearer Service
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Slide title 40 pt Slide subtitle 24 pt Text 24 pt Bullets level 2-5 20 pt
2008-03-11
Interactive RAB (Internet access - PS)
Conversational RAB for UDI of 64 kbps (H.324M multimedia - CS)
Streaming RAB (CS) offers support for variable rate circuit switched data up to 57.6 kbps
Streaming RAB (PS) offers support for guaranteed rate packet switched data
Multiple RABs offers support for multiple RABs configured simultaneously to the same UE
one or more PS RABs together with maximum one CS RAB
Multiple PS RABs
Two classes of Radio Access Bearer Services are provided:
a) Services with resource reservation and fixed throughput, e.g. speech.
b) Services tolerating a variable throughput, e.g. Best Effort IP Packet Data.
The function is initiated from CN, over the Iu interface, by sending the RANAP message RAB Assignment Request towards UTRAN, asking for a RAB to be set up towards a UE for which an RRC connection already exists. RNC then checks if the requested type of bearer can be provided or not (admission control).
If the request comes from the circuit switched core network (request of type a above), RNC then sets up a terrestrial link (AAL2 connection) between CN and UTRAN. Resources in RNC and Node B are allocated (including among other things allocation of new uplink and downlink channelisation codes for the physical channel, if there is a need to increase the bandwidth), a terrestrial link (AAL2 connection) is set up between RNC and Node B, and Node B connects the new bearer service to the existing dedicated radio link upon request from RNC. The UE is then informed about the new RAB via Radio Resource Control (RRC) signaling from RNC. Finally, CN is informed that the new RAB is established through the RANAP message RAB Assignment Complete.
If the request instead comes from the packet switched core network (for R1 only request of type b above) the handling is the same as above except that no terrestrial link needs to be set-up between CN and UTRAN since the transport layer for user data is already established via network management (O&M) functions in this case.
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Slide title 40 pt Slide subtitle 24 pt Text 24 pt Bullets level 2-5 20 pt
2008-03-11
RAB Id
Included in the RANAP RAB Assignment Request to identify a specific RAB instance for a specific UE connection. Unique to the CN and UE connection
Internal RAB Id
RNC internal identifier representing the RAB type. Where multiple instances of a RAB type are supported, multiple Internal RAB Ids are defined
RNC Concepts - Radio Access Bearer Identities
SRB Only: 0
Conv CS Unknown Second (reserved): 3
Conv PS Speech: 4
Conv PS Unknown Second (reserved): 6
Streaming CS Unknown: 7
Streaming PS Unknown Second (reserved): 9
Interactive PS First: 10
interactive PS Second: 11
Interactive PS Third: 13
Internal RAB Id Mapping
a) Services with resource reservation and fixed throughput, e.g. speech.
b) Services tolerating a variable throughput, e.g. Best Effort IP Packet Data.
The function is initiated from CN, over the Iu interface, by sending the RANAP message RAB Assignment Request towards UTRAN, asking for a RAB to be set up towards a UE for which an RRC connection already exists. RNC then checks if the requested type of bearer can be provided or not (admission control).
If the request comes from the circuit switched core network (request of type a above), RNC then sets up a terrestrial link (AAL2 connection) between CN and UTRAN. Resources in RNC and Node B are allocated (including among other things allocation of new uplink and downlink channelisation codes for the physical channel, if there is a need to increase the bandwidth), a terrestrial link (AAL2 connection) is set up between RNC and Node B, and Node B connects the new bearer service to the existing dedicated radio link upon request from RNC. The UE is then informed about the new RAB via Radio Resource Control (RRC) signaling from RNC. Finally, CN is informed that the new RAB is established through the RANAP message RAB Assignment Complete.
If the request instead comes from the packet switched core network (for R1 only request of type b above) the handling is the same as above except that no terrestrial link needs to be set-up between CN and UTRAN since the transport layer for user data is already established via network management (O&M) functions in this case.
Slide title In CAPITALS 50 pt Slide subtitle 32 pt
RADIO BEARERS
Top right corner for field-mark, customer or partner logotypes. See Best practice for example.
Slide title 40 pt Slide subtitle 24 pt Text 24 pt Bullets level 2-5 20 pt
2008-03-11
Control Plane
The Control Plane implements the control of the Radio Access Bearers and the connection between the UE and the Network from different aspects (Requesting the service, controlling different transmission resources, handover etc). Also a mechanism for the transparent transfer of NAS messages is included.
The Control Plane Includes the Application Protocol, i.e. RANAP, RNSAP or NBAP, and the Signalling Bearer for transporting the Application Protocol messages.
User Plane
The User Plane implements the actual radio access bearer service, i.e. carrying user Data/Data Stream(s) through the access stratum The Data Stream(s) is/are characterised by one or more frame protocols specified for that interface.
RNC Concepts - Control and User Planes
NAS - Non Access Stratum
e.g. messages that are ‘transparent’ to the RNC, Location Area Update or if UE is on CS call and wants to set-up a PS call it will send a transparent message through the RNC to the PS CN to initiate call set up.
These messages are passed transparently through the RNC as the RNC will not perform any action upon them. If a UE is not connected to the UTRAN then its location is only known by the CN, thus if the UE moves into a new location area then it must report this to the CN, it will send this location area update as a NAS message. The NAS message is received by the RNC which peeks at it to see that it is a NAS message and forwards it toward the CN (see later slide on Location Area Update)
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Slide title 40 pt Slide subtitle 24 pt Text 24 pt Bullets level 2-5 20 pt
2008-03-11
RNC Concepts - Radio Interface Protocol Architecture
The radio interface protocols are required to set up, reconfigure and release radio bearer services
L3 - Network Layer
L2 - Datalink Layer
L1 Physical layer
L3 Radio Resource Control (RRC)
Establishment, maintenance and release of Radio Bearers (RB) for control and user data
Establishment, maintenance and release of related radio resources between UE and UTRAN
L2 Packet Data Convergence Protocol (PDCP)
IP header compression
L2 Radio Link Control (RLC)
Segmentation and re-transmission services for both control and user data
L2 Media Access Control (MAC)
Mapping of Logical channels to Transport channels
Transport Format and Transport Format Combination selection
Execution of switching between common and dedicated transport channels.
Slide title In CAPITALS 50 pt Slide subtitle 32 pt
A Radio Bearer (RB) represents a bearer between the UTRAN and the UE. Therefore RABs are realised via bearers between the Core Network and UTRAN and Radio Bearers between UTRAN and UE. In general there is a one to one mapping between RABs and RBs. Speech RAB is an exception where each 20ms sample of speech is coded into three classes, A, B and C with different requirements on channel coding due to different sensitivity to errors. Each class is transferred via a separate radio bearer.
Signalling Radio Bearers (SRB) are defined to allow control plane signalling between UTRAN and the UE and between the UMTS Core Network (Non Access Stratum) and the UE. They represent the bearer between the UTRAN and the UE over which such signalling is transferred. There are four SRBs, SRB 1, 2, 3 and 4 for dedicated control channel (DCCH) signalling with:
SRB 1 used for RRC unacknowledged mode
SRB 2 for RRC acknowledged mode
SRB 3 for Non Access Stratum high priority Signalling
SRB 4 for Non Access Stratum low priority Signalling
SRB 0 is used for common control channel (CCCH) signalling
Signalling between the UTRAN and the Core Network is via Signalling Connection Control Part (SCCP) connections, with a SCCP connection (a logical connection over a physical link) established for each UE to each Core Network (PS and CS) as needed.
RNC Concepts - Radio Bearers
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Slide title 40 pt Slide subtitle 24 pt Text 24 pt Bullets level 2-5 20 pt
2008-03-11
RB Identity
UTRAN identifier configured in UE to represent a specific Radio Bearer
RNC is responsible for allocation of RB Identity, based on hardcoded table
Incoming CN Relocation can trigger flexible allocation of RB Identity
RNC Concepts - Radio Bearer Identities
SRB1: 1
SRB2: 2
SRB3: 3
SRB4: 4
Conv CS Unknown: 12
RB Id Mapping
a) Services with resource reservation and fixed throughput, e.g. speech.
b) Services tolerating a variable throughput, e.g. Best Effort IP Packet Data.
The function is initiated from CN, over the Iu interface, by sending the RANAP message RAB Assignment Request towards UTRAN, asking for a RAB to be set up towards a UE for which an RRC connection already exists. RNC then checks if the requested type of bearer can be provided or not (admission control).
If the request comes from the circuit switched core network (request of type a above), RNC then sets up a terrestrial link (AAL2 connection) between CN and UTRAN. Resources in RNC and Node B are allocated (including among other things allocation of new uplink and downlink channelisation codes for the physical channel, if there is a need to increase the bandwidth), a terrestrial link (AAL2 connection) is set up between RNC and Node B, and Node B connects the new bearer service to the existing dedicated radio link upon request from RNC. The UE is then informed about the new RAB via Radio Resource Control (RRC) signaling from RNC. Finally, CN is informed that the new RAB is established through the RANAP message RAB Assignment Complete.
If the request instead comes from the packet switched core network (for R1 only request of type b above) the handling is the same as above except that no terrestrial link needs to be set-up between CN and UTRAN since the transport layer for user data is already established via network management (O&M) functions in this case.
Top right corner for field-mark, customer or partner logotypes. See Best practice for example.
Slide title 40 pt Slide subtitle 24 pt Text 24 pt Bullets level 2-5 20 pt
2008-03-11
RB Type
RNC MOM enum used to distinguish Radio Bearer specific MO instances (UeRcRb, UeRcTrCh etc)
Used internally in UEH to distinguish different services (speech, packet, etc)
Used in UEH for transport bearer handling (determination of transport bearers to add/remove, identifying specific transport bearer instances etc.)
RNC Concepts - Radio Bearer Types
uehRbRrc: 0
uehRbSpeech: 1
uehRbPacket: 2
uehRbCsFix: 3
uehRbCsVar: 4
uehRbPsStreaming 5
uehRbPacketAdch 6
uehRbPacketHs 7
uehRbPacket2: 8
uehRbPacket3: 9
uehRbPacketHs2: 10
uehRbPacketHs3: 11
uehRbpacketAdch2: 12
uehRbPacketAdch3: 13
uehRbPsStreamingHs: 14
uehRbPsStreamingAdch 15
a) Services with resource reservation and fixed throughput, e.g. speech.
b) Services tolerating a variable throughput, e.g. Best Effort IP Packet Data.
The function is initiated from CN, over the Iu interface, by sending the RANAP message RAB Assignment Request towards UTRAN, asking for a RAB to be set up towards a UE for which an RRC connection already exists. RNC then checks if the requested type of bearer can be provided or not (admission control).
If the request comes from the circuit switched core network (request of type a above), RNC then sets up a terrestrial link (AAL2 connection) between CN and UTRAN. Resources in RNC and Node B are allocated (including among other things allocation of new uplink and downlink channelisation codes for the physical channel, if there is a need to increase the bandwidth), a terrestrial link (AAL2 connection) is set up between RNC and Node B, and Node B connects the new bearer service to the existing dedicated radio link upon request from RNC. The UE is then informed about the new RAB via Radio Resource Control (RRC) signaling from RNC. Finally, CN is informed that the new RAB is established through the RANAP message RAB Assignment Complete.
If the request instead comes from the packet switched core network (for R1 only request of type b above) the handling is the same as above except that no terrestrial link needs to be set-up between CN and UTRAN since the transport layer for user data is already established via network management (O&M) functions in this case.
Top right corner for field-mark, customer or partner logotypes. See Best practice for example.
Slide title 40 pt Slide subtitle 24 pt Text 24 pt Bullets level 2-5 20 pt
2008-03-11
dedicated to the transfer of a…