docslide.us c01 wcdma rno qos in umts network (1)
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April 20, 2023 By Ying weiminApril 20, 2023 By Ying weimin
QoS in UMTS Network
UMTS QoSUMTS QoS
UMTS QoS conceptQoS requirement on UMTSQoS mechanism in UMTS QoS in UMTS network UTRAN mechanism
CONTENT:
UMTS QoS conceptUMTS QoS concept
Quality of Service (QoS) refers to the collective effect of service performance that determines the degree of satisfaction of the end-user of the service.
Why UMTS QoS is so important -1G cellular system (AMPS) Analog voice/ circuit switch -2G cellular system (GSM) Digital voice/circuit switch -2.5G cellular system (GPRS) Digital data/ packet switch Address QoS issues but not required to implement. -3G cellular system (wcdma) Digital voice/data/ packet switch QoS features are designed in and ready for providing packet multi-medium service. Cellular system can server as “mobile internet”.
UMTS QoS conceptUMTS QoS concept
UMTS QoS conceptUMTS QoS concept
UMTS QoS classes(1) :
Conversational class speech, video telephony most delay sensitive Streaming class can tolerate some delay jitter should be minimized
Interactive class web browsing less stringent delay better error rate
UMTS QoS conceptUMTS QoS concept
UMTS QoS classe(2) :
Background class
Email, downloads
Error rate minimized
Lower priority in scheduling than interactive class
Uses resource only when interactive class don’t need the them
UMTS QoS conceptUMTS QoS concept
Delay tolerant
Bit error tolerant
background
conversational
streaming
interactive
UMTS QoS classe(3) :
UMTS QoS conceptUMTS QoS concept
Qos impact on resources
RequiredNetwork
Resources
Delay Delay
RequiredBufferingResources
UMTS QoS conceptUMTS QoS concept
QoS attibutes(1):Traffic Class:
Conversational , Streaming, Interactive, Background;
Traffic class indicates the type of application for which the UMTS bears is optimized.
Max Bit Rate
Maximum bit rate is defined as maximum number of bits delivered by the UMTS and within a period of time, divided by the duration of the period.
Guaranteed Bit Rate
Guaranteed bit rate is defined as the guaranteed number of bits delivered by the UMTS within a period of time, divided by the duration of the period.
UMTS QoS conceptUMTS QoS concept
QoS attibutes(2):Delivery Order
Delivery order indicates whether the UMTS bearer service should offer in-sequence SDU delivery or not.
Max SDU Size
Maximum SDU size indicates the maximum allowed size of an SDU.
Transfer Delay
Transfer delay is defined as the maximum delay for the 95th percentile of the distribution of delay for all delivered SDUs during the lifetime of the bearer service.
UMTS QoS conceptUMTS QoS concept
QoS attibutes(3):SDU Format Information
List of possible exact sizes of SDUs. SDU Error Ratio
SDU error is defined as the fraction of lost or erroneous SDUs.
Residual Bit Error Ratio
Residual bit error ratio indicates the undetected bit error ratio in the delivered SDUs if error detection has been requested, otherwise it indicates the bit error ratio (BER) in the delivered SDUs.
UMTS QoS conceptUMTS QoS concept
QoS attibutes(4):Delivery of Erroneous SDUs
Indicates whether SDUs detected as erroneous shall be delivered or discarded Traffic Handle Priority
Specifies the relative importance for handling of all SDUs belonging to the UMTS bearer compared to the SDUs of other bearers.
Allocation/Retention Priority Specifies the relative importance compared to other
UMTS bearers for allocation and retention of the UMTS bearer. The Allocation/Retention Priority attribute is a subscription attribute which is not negotiated from the mobile terminal.
UMTS QoS conceptUMTS QoS concept
Call Setup Quality:― Accessibility
• No coverage• Network equipment down• Cell barred• Generic call setup failure (signaling or other
reason)― Call Blocking Probability
• A blocking event occurs when the network admission controller denies the user’s access attempt.
― Call Setup Delay• The call setup delay is measured from the time
instant when the user places an access request, or query, to the instant when the user data exchange become possible with the other end of the call entity.
UMTS QoS conceptUMTS QoS concept
Call Quality ( Key parameters are covered by QoS Atributes )― Acceptable Delay Variation
• This is used to define how much jitter the application can tolerate, beyond which the packet is treated as being lost.
― Acceptable Transport Service Interruption Duration
• This defines to what degree an interrupt to transport services is regarded as acceptable, provided it happens only occasionally during a call.
― Call Drop Probability
• A call drop is defined as an event where the communication connection has
UMTS QoSUMTS QoS
UMTS QoS conceptQoS requirement on UMTSQoS mechanism in UMTS QoS in UMTS network UTRAN mechanism
CONTENT:
QoS requirement on UMTSQoS requirement on UMTS
Errortolerant
Errorintolerant
Conversational(delay <<1 sec)
Interactive(delay approx.1 sec)
Streaming(delay <10 sec)
Background(delay >10 sec)
Conversationalvoice and video
Voice messagingStreaming audio
and videoFax
E-mail arrivalnotificationFTP, still image,
paging
E-commerce,WWW browsing,Telnet,
interactive games
Conversational voice and video
Voice messaging Streaming audio
and video Fax
E-mail arrival notification FTP, still image,
paging
E-commerce, WWW browsing, Telnet,
interactive games
QoS requirement on UMTSQoS requirement on UMTS
Traffic class
conversational class
Streaming class
Interactive class
Background class
Maximum bit rate (kbps)
< 2048 < 2048 < 2048 < 2048
Delivery order Yes/No Yes/No Yes/No Yes/No
Maximum SDU size <=1500 <=1500 <=1500 <=1500
Delivery of erroneous SDU
Yes/No Yes/No Yes/No Yes/No
Residual BER 5*10-2 – 10-6 5*10-2 – 10-6 4*10-3 – 6*10-8 4*10-3 – 6*10-9
SDU error ratio 10-2 – 10-5 10-1 – 10-5 10-3 – 10-6 10-3 – 10-6
Transfer delay100ms upto FFS
250ms upto FFS
Guaranteed bit rate < 2048 < 2048 Traffic handling priority
1,2,3
Allocation and retention priority
1,2,3 1,2,3 1,2,3 1,2,3
QoS attributers (Profile) :
QoS requirement on UMTSQoS requirement on UMTS
QoS example(1):
AMR speech codec payloadBit rate: 4,75 - 12,2 kbit/sDelay: end-to-end delay not to exceed 300ms BER: < 10-3
FER < 1 % (with graceful degradation for higher erasure rates)
QoS requirement on UMTSQoS requirement on UMTS
QoS example(2):
Videophone carries both video and audio and intended for use in a conversational environment. As such, in principle the same delay requirements as for conversational voice will apply, In fact, due to the long delays incurred in even the latest video codecs, it will be difficult to meet these requirements.
Once again, the human eye is tolerant to some loss of information, so that some degree of packet loss is acceptable depending on the specific video coder and amount of error protection used. It is expected that the latest video codecs will provide acceptable video quality with frame erasure rates up to about 1%.
UMTS QoSUMTS QoS
UMTS QoS conceptQoS requirement on UMTSQoS mechanism in UMTS QoS in UMTS network QoS mechanism in UTRAN
CONTENT:
QoS in UMTSQoS in UMTS
Subscriber#1
PDP context #3PDP context #2
PDP context #1-----------------
PDP context IDAPN Qos Profile
RNC SGSN GGSNUEHLR
UMTS QOS Classes :
Conversational class Steaming classInteractive class
Background class
QoS profile configuration:
QoS in UMTS networkQoS in UMTS network
PDP context
PDP context
1
2
3
3’
4’
4
5’
5
5
5’
Attach
PDP Context Activation
Subscribe time
IP Qos mapping & establishment
RAB establishment
QoS map to radio access bearers
PDP modification
IP-QoS remapping if required
RL/RB estabilishment
RRM to map QoS to channals
RNC SGSN GGSNUE HLR
General idea:
QoS in UMTS networkQoS in UMTS network
Subscriber#1
PDP context #3PDP context #2
PDP context #1-----------------
PDP context IDAPN Qos Profile
SGSN GGSNUE HLR
Subscriber#1
PDP context #3
PDP context #2
PDP context #1-----------------
PDP context IDAPN PDP address Qos Profile
1.Attach Req2.Insert Sub.Data
4.Attach Acpt
3.Insert sub. Data Ack
Subscribers attach to net work
QoS in UMTS networkQoS in UMTS network
Subscriber#1
PDP context #3
PDP context #2
PDP context #1-----------------
PDP context IDAPN PDP address Qos Profile
SGSN GGSNUE
Host RNC
1 Activate PDP Context Req (QoS Req)
4 RAB Setup (QoS Neg)
5 RL/RB Establishment
6 RAB Est.Rsp
2 Activate PDP Context Req (QoS Neq)
3 Activate PDP Context Rsp (QoS Neq)
SGSN may restrict requested QoSGiven its capabilities, load and the
Subscribed QoS
SGSN selects radio priority based on QoS negotiated
GGSN may further restrict the QoS given its capabilities
and load
RRM Algorithms
Admission control and QoS session establishment:
QoS in UMTS networkQoS in UMTS network
Subscriber#1
PDP context #3
PDP context #2
PDP context #1-----------------
PDP context IDAPN PDP address Qos Profile SGSN GGSN
UEHost RNC
9 Active PDP context Acpt (QoS Neg)
7 Update PDP Context Req (QoS Neq)
8 Update PDP Context Rsp (QoS Neq)
In case QoS was downgraded by RNC , SGSN may inform GGSN about the new QoS
MS either accepts the QoS or deactivates the PDP context
Admission control and QoS session establishment:
QoS in UMTS networkQoS in UMTS network
New SGSN Old SGSNUE
GGSN RNC
5 RA Update Acpt / Complete
1 RA Update Req
4 Update PDP Context Rsp (QoS Neq)
2 SGSN Context Req/Ack.(QoS profile)
3 Update PDP Context Req (QoS Neq)
Inter SGSN RA update:
QoS in UMTS networkQoS in UMTS network
Old SGSN New SGSNUE GGSN Target RNC
6 Relocation command
1 Relocation required (Source ID, target ID, SRNC-TRNC container)
4 Relocation Req ack ( RABS ok, RABS fail)
2 Forward Rel. Req( PDP Context)
3 Relocation Req (SRNC-TRNC container,RABS)
Serving RNC Relocation:
Source RNC
5 Forward Rel. Rsp
7 Relocation commit
8 Relocation of data
Establishment of RABs, RBs
QoS in UMTS networkQoS in UMTS network
Old SGSN New SGSNUE GGSN Target RNC
15 Iu release command
9 Relocation detect
12 Relocation Comlete
10 Update PDP context Req(Qos.neq)
Source RNC
13 Forward Rel. comp
11 Update PDP context Rsp
14 Forward Rel. comp.ack
16 Iu release complete
Serving RNC Relocation:
UMTS QoSUMTS QoS
UMTS QoS conceptQoS requirement on UMTSQoS mechanism in UMTS QoS in UMTS network
QoS mechanism in UTRAN
CONTENT:
QoS mechanism in UTRANQoS mechanism in UTRAN
PHY
MAC
RLC
RRC
PDCP
BMC
L1
L2
L3
Signaling Radio Bearers
User Plane Radio Bearers
Transport channel
Logical channel
Radio interface protocals:
QoS mechanism in UTRANQoS mechanism in UTRAN
PDCP
Packet data convergence protocol :Header compression and decompression of IP data
stream.Maintenance of PDCP sequence number for radio
bearers that are configured to support lossless SRNS relocation.
QoS mechanism in UTRANQoS mechanism in UTRAN
RLC
RLC mode Transparent mode : no overhead is added to higher layer
data. Unacknowledged mode: no retransmission protocol is
used and data delivery in not guaranteed. Acknowledged mode: Automatic repeat request (ARQ)
mechanism is used for error correction.RLC function: segmentation and reassemble ; ARQ error correction ciphering
QoS mechanism in UTRANQoS mechanism in UTRAN
TFCS
TrCH#1
TFS
TF
TrCH#2TrCH#3TrCH#4
TFC
MAC function:
• Priority handling between different data flow is done by MAC;
• Transport Formation Selection , It control transport format for each flow.
QoS mechanism in UTRANQoS mechanism in UTRAN
Prameters valueRadio resource
mapping
Maximum bit rate (kbps) 128 Spreading factor =16
Maximum SDU size 1500 map to transport format
Residual BER 10-6 1/3 Turbo codec,Acknowledged RLC
Delivery of erroneous SDU No RLC configuration
Transfer delay Na interlever 10-80 ms
Guaranteed bit rate 64 Spreading factor =64
SDU error ratio 1%Set appropriate
threshold for open loop power control
delivery order yes RLC configuration
Mapping from QoS attributers to radio resource
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