HSDPA Principles

HSDPA Principles Seminar

Corrado Carbone - RO/QoS South

2

Agenda

3. Channel Structure3. Channel Structure3. Channel Structure3. Channel Structure

2. Architecture2. Architecture2. Architecture2. Architecture

1. Overview1. Overview1. Overview1. Overview

5. InterFrequency Mobility Principles5. InterFrequency Mobility Principles5. InterFrequency Mobility Principles5. InterFrequency Mobility Principles

6. Capacity Management6. Capacity Management6. Capacity Management6. Capacity Management

4. Accessibility & Mobility Principles4. Accessibility & Mobility Principles4. Accessibility & Mobility Principles4. Accessibility & Mobility Principles

7. KPIs7. KPIs7. KPIs7. KPIs

3

Outline

• Let’s get used with the main concepts of the HSDPA.

• HSDPA introduces new technologies in the UMTS world and consequently a new way to manage PS traffic.

• The most important impacts of it are on:– Modulation

– Retransmission schemes

– Scheduling

– Usage of Power and Code

• This presentation reports an overview of the main issues to take in mind.

4

HSDPA Basic Principles

5

1 - Shared Channel Transmission (1/2)

• Shared-channel transmission implies that a certain amount of radio resources of a cell (codes and power) is seen as a common resource that is dynamically shared between users.– The idea is that a part of the total downlink code resource is dynamically shared between a set

of packet-data users, primarily in the time domain. – The codes are allocated to a user only when they are actually to be used for transmission,

leading to efficient code and power utilization.

• For P4 only 5 codes (SF = 16) will be available for the HSDPA feature and they will be shared on a time base.

Channelization codes allocatedfor HS-DSCH transmission

5 codes (example)SF=16

SF=8

SF=4

SF=2

SF=1

User #1 User #2 User #3 User #4

TTI

Shared channelization

codes

6

1 - Shared Channel Transmission (2/2)

• The Shared-channel transmission allows:– Higher peak bit rate: all the resource can be allocated to a single user in case of low

load.

– Better application performance being closer to the model TCP has being designed for.

– More efficient utilization of available code resources compared to the use of a dedicated channel, i.e. reduced risk for code-limited downlink.

• The Shared-channel transmission impacts:– Scheduling become more complex

7

2 - Short 2 ms TTI (1/2)

• The Transmission Time Interval becomes extremely short in HSDPA; 2 ms compared to the 10 ms used by R99 high bit rate radio bearer.

• The HS channels are organised in sub-frame of 3 slots each; this means that the slot time 2/3 ms/slot is the same as for R99 slots (10/15 ms/slot).

• The scheduling and the link adaptation algorithms work at this frequency!

10 ms20 ms40 ms80 ms

Earlier releases

2 msRel 5 (HS-DSCH)

2 ms

8

2 - Short 2 ms TTI (2/2)

• The shorter TTI allows:

– Reduced air-interface delay: this is required by the the TCP at high data rates to Improved end-user performance

• The shorter TTI is necessary to benefit from other HSDPA features:

– Fast Link Adaptation

– Fast hybrid ARQ with soft combining

– Fast Channel-dependent Scheduling

2 ms

9

3 - HSDPA – Power Allocation

• HS-DSCH allocated power is decided by the RNC, prioritizing the DCH channel

• HS-DSCH adjusts the data rate to match the instantaneous radio conditions and the available transmission power in the RBS– No closed loop power control is specified for HS-DSCH, unlike the DCH channel

• The system adjusts the data rate by– varying the effective code rate– changing the modulation scheme

• This leads to a higher efficiency in the usage of power.

Dedicated channels (power controlled)

Common channels

Power usage with dedicated channels channels

t

Unused power

Power

HS-DSCH with dynamic power allocationt

Dedicated channels (power controlled)

Common channels

HS-DSCH (rate controlled)

To

tal

ce

ll p

ow

er

Power

To

tal

ce

ll p

ow

er

3GPP Release 99 3GPP Release 5

10

Link Adaptation

Available Power

4 - Fast Link Adaptation (1/3)

• The target for the link adaptation is to select a TFRC (Transport Format and Resource Combination) resulting in transmitting an as large transport block as possible with a reasonable error probability.

Channel ConditionCoding

Modulation

TFC

Bit Bit RateRate

UE category

Traffic (buffers state)

11


• Adjust transmission parameters to match instantaneous channel conditions

• HSDPA: Adapt on 2 ms TTI basis the Rate (“constant” power)– Adaptive coding

– Adaptive modulation (QPSK or 16QAM)

• Link adaptation is implemented by allowing the MAC-hs to set the TFRC (Transport Format and Resource Combination) independently for each 2 ms HS-DSCH TTI

High data rate

Low data rate

feedback

12


• In order to estimate current channel conditions, an estimate of the Channel Quality is reported by the UE to RBS (CQI).

• Based on the channel conditions and the available power, the network will select the Transport Format to have the maximum throughput achievable

High data rate

Low data rate

feedback

13

• Scheduling = which UE to transmit to at a given time instant

• There is a main tradeoff to choose between:

fairness vs.vs. cell throughput

5 - Fast Channel-dependent Scheduling (1/2)

Every user has the same “rights to

access the resource”

The user with better radio condition transmit more

User1 User2 User3 User4

time2 ms 2 ms

14

5 - Fast Channel-dependent Scheduling (1/2)

• 2 opposite strategies are: – Round Robin: radio resources are allocated to communication links on a sequential

basis.

– Proportional Fair: transmit at fading peaks. This may lead to large variations in data rate between users.

high data rate

low data rate

Time

#2#1 #2 #2#1 #1 #1

User 2

User 1

Scheduled user

15

6 - Fast Hybrid ARQ with Soft Combining (1/2)

• HSDPA introduces a new retransmission level “under” the RLC scheme in the RNC.

• This new “level” allows rapid retransmissions of erroneous data:– Hybrid ARQ protocol terminated in RBS

short RTT (typical example: 12 ms)

– Soft combining in UE of multiple transmission attempts reduced error rates for retransmissions

P1,1

P1,1

NA

CK

P1,2

P1,2

AC

K

P2,1

P2,1

NA

CK

P2,2

P2,2

AC

K

P3,1

AC

K

P1,1 P2,1 P3,1

+ +

Transmitter

Receiver

16

6 - Fast Hybrid ARQ with Soft Combining (2/2)

• A fundamental difference between conventional ARQ (used in RLC) and HARQ is that:– in the latter case received data blocks that cannot be correctly decoded are not

discarded but buffered

– They are soft combined with later received retransmissions of the same set of information bits.

– Finally, decoding is applied to the combined signal.

17

7 - UE capabilities

• The UE capabilities are divided into a number of parameters:– Total RLC AM and MAC-hs buffer size

– Maximum number of HS-DSCH transport channel bits received within a HS-DSCH TTI

– Support of HS-PDSCH Yes/No

– Maximum number of HS-DSCH codes received

– Total number of soft channel bits in HS-DSCH

– Minimum inter-TTI interval in HS-DSCH

– Supporting 16QAM

• These physical layer UE capabilities can be translated in a limit on the requirements for 3 different UE resources: – the de-spreading resource (codes decoded in parallel)

– the soft buffer memory used by the hybrid ARQ functionality

– the turbo decoding speed (the maximum number of transport channel bits received within an HS-DSCH TTI and the minimum inter-TTI interval).

18

Throughput level: UE type cat 12

• There are several levels for throughput calculation: let’s clarify!

• The biggest MAC-HS transport block size is 3440 including HS header and padding bits:

X 10 = + + = 3440 bitsRLC SDU = 320

RLChead = 16

MAC- HS SDU head = 3360

MAC- HS head = 21

Padding bits = 59

That means the DSCH max scheduled bit rate could be 1720 kb/s: That is including headers, padding and every type of retransmission

This is the level used by the RBS counters and Couei!

This corresponds to a max RAB bit rate of 1600 kb/s =320*10/2

In reality considering at least the HS retransmissions at this level the maximum bit rate could not be higher

than 1600*0.9 =1440 bit/s

19

Agenda








20

Protocol stacks (1/4)

UE RBS SRNC

PHY

AAL2ATM

FPMAC-hs

L1

RLCUser Data

PHY PHY

AAL2ATM

AAL5ATM

GTP-UUDP/IP

FP

RLCMAC

CN

PHY

AAL5ATM

GTP-UUDP/IP

User Data

Uu Iub Iu

The figure shows the R99 protocol stack.Note in particular that MAC is a protocol between the RNC and the UE

MAC

L1

21


UE RBS SRNC

PHYL1

AAL2ATM

MAC-hs

HS-DSCHFP

MAC-d

MAC-hs

L1

RLCUser Data

PHY PHY

AAL2ATM

AAL5ATM

GTP-UUDP/IPHS-DSCH

FP

RLCMAC-d

CN

PHY

AAL5ATM

GTP-UUDP/IP

User Data

Uu Iub Iu

The new radio interface layer 2 functionality required by the HS-DSCH (hybrid ARQ signaling, scheduling, etc) was placed in a new functional entity of the MAC layer, called MAC-hs. The physical layer was updated with new functionalities for HS-DSCH (soft combining of retransmitted transport blocks, new physical channels, etc.).

22


UE RBS SRNC

PHYL1

AAL2ATM

MAC-hs

HS-DSCHFP

MAC-d

MAC-hs

L1

RLC

RRC

PHY PHY

AAL2ATM

AAL5ATM

GTP-UUDP/IPHS-DSCH

FP

RLCMAC-d

CN

PHY

AAL5ATM

GTP-UUDP/IP

RRC

Uu Iub Iu

A new user-plane frame-handling protocol (UP FP) between the SRNC, DRNC and Node B needed to be developed for the radio network layer (RNL). It was based on the release 99 DSCH UP FP used over Iur.The layer 3 control-plane protocols (RRC, RNSAP and NBAP) needed to be updated with control procedures, handling HS-DSCH.

23


UE RBS SRNC

PHYL1

AAL2ATM

MAC-hs

HS-DSCHFP

MAC-d

MAC-hs

L1

RLC

TCP/IP

PHY PHY

AAL2ATM

AAL5ATM

GTP-UUDP/IPHS-DSCH

FP

RLCMAC-d

CN

PHY

AAL5ATM

GTP-UUDP/IP

TCP/IP

Uu Iub Iu

Note that RLC does not have significant impactWhen the HS-DSCH transport channel is used with AM RLC, it is expected that RLC re-transmissions will be required only in rare circumstances where the inner hybrid ARQ fails.

E.g. in handover situations, the transmit and receive buffers in the MAC-hs layer may need to be re-initialized. This may cause data loss, which would be taken care of by RLC retransmission.

24

General impacts of the new architecture

• There will be impacts on the buffer capabilities– for data in the RBS a new buffer is needed to store data of different

users

– The mobile has to store erroneous PDU for Soft Combining

– Requirements on buffer could be different due to the new amount of transmitted data

• Algorithms have to be adapted:– Admission and Congestion Control for example need new way to

estimate the load and accept new users.

– Closed loop power control does not apply to HS.

– New algorithms that manage the new functionalities have to be introduced (buffer, scheduling).

• Mobility algorithm in particular is conditioned since the fast link adaptation does not allow the Soft Handover anymore.

• The e2e performance of the PS users significantly improves due to a smaller RTT.

25

• RBS– New TX board in RBS

• RNC– No HW upgrades

– Only SW!!

– Setup of HS-DSCH/HS-SCCH

HSDPA Basics: Node Impacts

R99: • Scheduling, • TF selection, • Link layer retransmission (ARQ)

Core Network

RNC

Node BHSDPA: • Scheduling, • Link Adaptation, • Hybrid ARQ

26

Node Functionality

Iub

Iur

Iu

Associated Dedicated ChannelsHS-DSCHHS-SCCH

HS-DPCCH

RNC Function:

RAB establishment & release

Channel switching

Mobility

Resource handling

Capacity management

L2 (MAC-d)

UL HS control channel power control

Certain flow control

RNC

27

Node Functionality

RBS Function:

L2 (MAC-hs)

Scheduling

HARQ process handling

Transport format selection

Certain flow control

DL HS shared control power control

Iub

Iur

Iu


HS-DPCCH

RNC

28

Agenda








29

HSDPA new channels

• HSDPA introduces specific channels, 1transport and 3 physical channels:– The transport channel High Speed Downlink Shared Channel (HS-DSCH) is a

resource existing only in downlink and carries user data in HSDPA.

– The High Speed Physical Downlink Shared Channel (HS-PDSCH) is a downlink physical channel, to which the HS-DSCH channels are mapped.

– The High-Speed Shared Control Channels (HS-SCCH) is used for downlink control signaling and carries indication about UE scheduling.

– One Associated Dedicated Channel (A-DCH) pair (UL & DL) per HSDPA user in connected state, used for control signaling and uplink data transmission. The uplink control information is carried by the Uplink High Speed Dedicated Physical Control Channel (HS-DPCCH).

A-DCHHS-DSCHHS-SCCHHS-DPCCH

30

Channel Structure


HS-DPCCH

Control ChannelControl Channel

HS-PDSCH High-Speed Physical Downlink Shared Channel (Physical)HS-PDSCH High-Speed Physical Downlink Shared Channel (Physical)

HS-DPCCH – High-Speed (related uplink) Dedicated Physical Control ChannelControl Channel (Physical)

HS-DPCCH – High-Speed (related uplink) Dedicated Physical Control ChannelControl Channel (Physical)

A-DCH – Associated Dedicated Channel – A-DCH (Transport)A-DCH – Associated Dedicated Channel – A-DCH (Transport)

HS-SCCH – High-Speed Shared Control Channel(s)Control Channel(s) (Physical)HS-SCCH – High-Speed Shared Control Channel(s)Control Channel(s) (Physical)

HS-DSCH – High-Speed Downlink Shared Channel (Transport)HS-DSCH – High-Speed Downlink Shared Channel (Transport)

31

An overview of HS-DSCH and its associated channels

CN RNC RBS UE

-

DPCCH

DPDCH

HS DPCCH

HS-SCCH

HS-PDSCHHS -DSCH

DCCH

DCCH

DTCHInteractive PS RAB



DCCHNAS

DCCHNAS

RRC

User 1

User 2

User n

For each user

Radio Access Bearers: - Interactive - Background

Logical Channels:-Dedicated Control Channel, DCCH-Dedicated Traffic Channel, DTCH

Transport Channels:-Dedicated Channel, DCH-High-Speed Downlink Shared Channel, HS-DSCH

Physical Channels:-Dedicated Physical Channel, DPCH -DPCCH, Dedicated Physical Control Channel-DPDCH, Dedicated Physical Data Channel-HS-DPCCH, HS-DSCH Dedicated Physical Control Channel-HS-DSCH Shared Control Channel, HS-SCCH-High Speed Physical Downlink Shared Channel, HS-PDSCH

DPCHDCH

DCH

Iu Iub Uu

32

HS-DSCH : High-Speed Dedicated Shared Channel

• HS-DSCH is the transport channel used for data transmission on the downlink and is shared by all users in the cell. In the HSDPA first phase product release:– the sharing of code resource is done in the time domain on a 2 ms time basis

(TTI).

– The shared code resource consists of 5 channelization codes with fixed spreading factor SFHS-DSCH = 16, in this time frame.

• The HS-DSCH cannot be in soft/softer handover and no fast power control is used.

• The HS-DSCH uses all the excess power from the available transmission power at the base station left from the common and dedicated channels

33

HS-SCCH: High-Speed Shared Control Channel

• HS-SCCH is a downlink physical channel used to carry HS-DSCH related control signaling (Physical Layer signaling).

• It is shared among the HSDPA users on time division basis (TTI), with the same scheduling as for HS-DSCH.

• All UEs listen to the same HS-SCCH channel and after decoding, decide whether the information to start listening the HS-PDSCH was intended to that UE.

• Informs the UE about:– HS-DSCH code set– Modulation scheme (QPSK/16QAM)– HS-DSCH transport format (number of transport blocks per TTI and number of

bits per transport block)– Hybrid ARQ information

• Never in soft handover

• The HS-SCCH has a spreading factor SFHS-DSCH = 128

34

A-DCH: Associated Dedicated Channel

• One A-DCH pair is set up for every HSDPA user in connected state.

• It is used for control signaling (RRC and NAS) in UL and DL.

• It is a new Radio Bearer corresponding to a 3.4 kbps SRB in the DL (Sf 256).

• In the uplink A-DCH is also used as the channel for data transmission, where the rate can be either 384 kbps or 64 kbps. – The uplink data rate 384 kbps is selected as first priority and 64 kbps is used as a

fall back rate if the path loss is judged to be too large or 384 kbps radio bearer setup fails for any reason (e.g. lack of radio or hardware resources).

• The uplink A-DCH channel also contains the High-Speed Dedicated Physical Control Channel (HS-DPCCH), the new physical channel that carries the L1 related signaling in UL.

35

HS-DPCCH: High-Speed Dedicated Physical Control Channel

• It is used for transmitting the following information from UE to RBS:– HARQ acknowledgement (1 bit coded in 10)

– Channel quality indicator (5 bits coded to 20 bits in 2 slots)– channel quality measurements based on CPICH– reporting rate is configurable through RRC/NBAP signaling– information reflecting the instantaneous downlink radio channel conditions to assist the

RBS in the transport format selection (fast link adaptation) and the scheduling

– The HS-DPCCH has a spreading factor SFHS-DSCH = 256

• The A-DCH both UL and DL can be in soft/softer handover whilst the HS-DPCCH can never be in soft handover (softer is possible).

• HS-DPCCH (UL) is transmitted within a dedicated channel. The main idea is that it is power controlled from the other part of the A-DCH.

36

HSDPA Channel Operation

HS-DPCCH: CQI

HS-SCCH: DL Transfer Information

HS-DSCH: Data Transfer

HS-DPCCH: ACK/NACK

Physical Channels:-Dedicated Physical Channel, DPCH -DPCCH, Dedicated Physical Control Channel-DPDCH, Dedicated Physical Data Channel-HS-DPCCH, HS-DSCH Dedicated Physical Control Channel-HS-DSCH Shared Control Channel, HS-SCCH-High Speed Physical Downlink Shared Channel, HS-PDSCH

37

UserPlane: Overview

• There are 8 steps to transmit on the HS-DSCH:– In the RNC, the Interactive RAB is mapped to a radio bearer to be transmitted on

the HS-DSCH.

– The radio bearer is then processed by the RLC and MAC-d layer 2 protocols in the RNC.

– The resulting MAC-d PDUs are transmitted over Iub to the RBS using the HS-DSCH frame protocol.

– The MAC–hs receive the Channel Quality Indicator “adjusted” by the Node B

– The MAC-hs scheduling function selects in each TTI the user to which the HS-DSCH is transmitted.

– Following the selection of a user, the user data to transmit on the HS-DSCH is put into one of several HARQ processes in the MAC-hs HARQ protocol.

– The amount of data to transmit is determined by the TFRC selection algorithm.

– Hence the data is transmitted to the UE over the air interface.

38

RAB/RB Combination – Overview

• Interactive and background Packet Service

• New RABs defined:– Interactive PS 64/HS

– PS 384/HS (optional)

• DL bit rate up to 4.32 Mbps in P4 (user data rate)

• About HS-DSCH:– Max. 5 codes

– DL: QPSK or

– DL: 16QAM (optional)

– UL 64 kbps interactive radio bearer

– Supported by symmetric 3.4 kbps signaling radio bearer (SRB)

39

Agenda








Accessibility:Accessibility:

Call setup phasesCall setup phases

Accessibility:Accessibility:

Call setup phasesCall setup phases

40

f2 HS

Radio network functions

RNC RNCIur

Iub Iub

Iu Iu


HS-DPCCH

Iub

f1 f1

f2 HS f2 HS

f1

f1 f1 f1

1

Camping in idle1Access the HSDPA system2

23

Move within the system3

4

Move out of the system4Control the power5

5

Decide which mobile and how much to transmit to it 6

6

RRM policy7

7

41

CS Streaming

SP0 not available

Note 1: It is possible to go to Idle from all states (Signaling connection release)Note 2: QoS profiling on the PS Int RAB is handled by Channel SwitchingNote 3: Same transitions is valid for PS Streaming 16/64 and PS Streaming 16/128Note 4: RAB establishment on FACH depending on the setting for parameter PacketEstMode

RAB Release

Channel Switching

RAB Establishment

UDI (CS64)PS Streaming+Int 8/8

SP0

SP64

UDI+Int. 8/8

Int. 64/128

Int. 64/384

Int. 64/64

Int. FACH

Speech

SRB

Other int. RAB state

SRBRAB est on FACH

New!

New!

New!

State Diagram – non HSDPA-P4

42

SRB-DCH

Idle

RAB Establishment

RAB Release

Signaling Connection handling

HS-DSCH(uplink 64 or 384)

The diagram is clearly much easier. What does it means?

Few transitions

Only 2 HS RABs existThe choice between 64 or 384 is done at the beginning and cannot be changed during the connection.

State Diagram – only HSDPA

43

Idle mode & RRC Connection Establishment

• In idle mode there is no difference between a user with HSDPA capability or not.

• The UEs select the the cell with best Ec/N0 with the procedure ”cell reselection” as in R99.

• In second carrier sites, HSDPA is deployed in the second carrier only– Most idle UEs will camp on f1

– Most HS users must be moved to f2 in order to get the ”HS service”

• There is no difference in the RRC Connection Establishment procedure between a user with HSDPA capability or not– RRC Connection Request and Radio Connection Setup Complete contains

information about the UE capability

f1 f1 f1

f2 HS f2 HS f2 HS

HS+ f1HS+f1

Ec/No

f1

f2

44

UTRAN

RANAP: RAB Assignment Request (establish PS Interactive/Background RAB)

Radio Bearer setup

RANAP: RAB Assignment Response

Serving HS-DSCH cell selection

SGSN UE

HSDPA capability analysis

SRB - DCH

Possible Inter frequency hard handover

RAB establishment

1

2

3

4

0

45

Capability analysis

• At the reception of RANAP RAB Assignment Request, if:– the present UE state is SRB-DCH and if the RAB mapping gives as result PS interactive

or PS background

– the “Access stratum release indicator” received from UE indicates Rel-5 or later release,

– the “Physical channel capability” received from UE indicates that the UE supports FDD HS-PDSCH (any HS-DSCH-physical-layer-category shall be supported),

– if the existing UE capability check for L2 are successful

The RNC performs the Serving HS-DSCH cell selection

UTRAN

RANAP: RAB Assignment Request (establish PS Interactive/Background RAB)


SGSN UE

HSDPA capability analysis

SRB - DCH

1

Otherwise the RAB is established in design base system.

46


• When, at RAB establishment, the UE starts the procedure 3 results are possible:

– If the HS-DSCH is enabled in the best cell, the connection is set up in that cell.

• Otherwise the RNC check the coverage relation of the best cell.

– If the HS-DSCH is enabled in the target cell, an hard handover is tried to the new selected cell.

– If no cells are available and the connection is established on an interactive DCH.

Current active set

New active set

DCH

2

47

Coverage relations

• The coverage relation is a unique uni-directional relation between two cells, a source and a target cell.

• The purpose of the coverage relation is to give the operator a possibility to distribute HSDPA downlink traffic among the cells of an RNC.

• The target cell covers almost the same area and can be assigned the same frequency or different ones. Typically the cells will be co-located.

A coverage relation is defined for a source cell with the parameters (3GPP R5 25.423):

hsPathLossThreshold utranCellRef (the target cell) coverageIndicator

2

48

Two Carriers scenario: IF HO

• In case the HSDPA is deployed on a second layer and the mobile access the network from the first layer the step will be the following:

f2 HS

f1

f2 HS f2 HS

f1 f1 f1

f1

Start the RAB establishment and the Cell Selection procedure..

When the attempt on the AS cells fails, check the coverage relation of the best cell and its path loss

2nd carrier

1st carrier

The mobile ask for a SRB establishment on a cell of Carrier 1

f1

If everything is ok, perform a BLIND IF-HO

f2 HS

f1 f1

f2 HS f2 HS

f1 f1 f1

f1If the IF HO succeed continue the RB set up on the new carrier..

Otherwise the RNC try to establish a R99 PS RAB on the first carrier

f2 HS

f1 f1

f2 HS f2 HS

f1 f1 f1

f1

3

49

Interfrequency load distribution

• It adds the possibility to configure a "load-sharing margin" which can be used to reserve output power, for e.g. HSDPA traffic, in selected cells

• It makes the cell appear more loaded than it actually is

• It can be used to push traffic on a specific carrier

50

8. Iub and Iur Transport Bearer setup, AAL2 Connection setup

7. NBAP: Radio Link Reconfiguration Ready

4. RNSAP: Radio Link Reconfiguration Prepare

9. Set Activation time

2. Allocate resources

1. Admission request

10. RRC: Radio Bearer Setup – R5

12. RRC: Radio Bearer Setup Complete

11. Perform actions at Activation time

UE SRNC DRNC

9. NBAP: Radio Link Reconfiguration Commit

9. NBAP: Radio Link Reconfiguration Commit

9.RNSAP: Radio Link Reconfiguration Commit

5. Allocate resources 5. Allocate resources

6. NBAP: Radio Link Reconfiguration Ready 6. RNSAP: Radio Link Reconfiguration Ready

4. NBAP: Radio Link Reconfiguration Prepare

3. NBAP: Radio Link Reconfiguration Prepare

4. Allocate resources

4. Admission request

RBS RBS DRNC

13. Release resources

RB setup (1/2)

• If the result from the “Serving HS-DSCH cell selection” gives that a Serving HS-DSCH cell is selected

-> the “RB setup, SRB-DCH to PS interactive (64 or 384)/HS - HS-DSCH transition” is performed

• If the result gives that no Serving HS-DSCH cell is selected, but UE connection is still maintained

-> the RAB establishment is performed as in the design base.

4

51

RB setup (2/2)

• Different levels of Admission control runs in the RNC– For the selected serving HS-DSCH cell, run Admission Control algorithm for the

A-DCH configuration and for HS-DSCH configuration (number of serving links).

– For the other cells within SRNC, run Admission Control algorithm for the A-DCH configuration.

• The RANAP RAB Assignment Response is sent to the CN when the Radio Bearer Setup Complete has been received.

• The handling of UL/DL user data on RLC level is done as in the R99 for PS interactive RB.

4

52

UL: 64 or 384?

• Which UL A-DCH to set is decided during the AC phase.

• From an AC point of view, there are 2 guaranteed-hs service types:– PS64/HS Interactive PS service with rate 64 kbps in uplink and HS-DSCH using

up to 5 HS-PDSCH codes in downlink.

– PS384/HS Interactive PS service with rate 384 kbps in uplink and HS-DSCH using up to 5 HS-PDSCH codes in downlink.

• A part from the other AC check there are 2 special checks for the UL A-DCH:– Histogram Admission Policy: requests demanding spreading factor 4 in uplink

(PS384/HS radio connection type) are compared with sf4AdmUl.

– The path loss is checked in order to understand if a 384 UL bearer can be sustained.

• If the 384 RB is denied (or is accepted but the RBS don’t find the synchronization in the establishment phase) the connection is established on the 64 RB.

4

53

Release of Iu-PS connection due to inactivity in HS-DSCH state (1/2)

• When a user finishes its transmission has to release the resources.

• The procedure is really simple:– An "HS-DSCH inactivity" timer is

started when there is no data to transmit.

– When the timer expires a Iu Release request is sent and the resources are released.

• The value of the timer is a system parameter hsdschInactivityTimer

54

Please note that..

• No Channel Switching, cell_DCH -> Idle:– No cell_FACH for HS users.

– No “soft” switch between HSDPA and DCH

– No transition between the UL rate is possible

– The UE can regulate its rate in UL depending on the cell interference level. Hence a 384 RB in UL has to be considered as the maximum bit rate.

SRB-

DCH Idle

HS-DSCH(uplink 64 or

384)

RAB Combinations:Interactive 64/HS kbps PS RAB UL: Interactive 64 kbps PS RB + 3.4 kbps

SRBs on DPCHDL: Interactive PS RB on HS-PDSCH + 3.4

kbps SRBs on DPCH

Interactive 384/HS kbps PSUL: Interactive 384 kbps PS RB + 3.4 kbps

SRBs on DPCHDL: Interactive PS RB on HS-PDSCH + 3.4

kbps SRBs on DPCH

55

Incoming CS call• A critical issue for the HSDPA in P4 is the

management of the incoming call.

• Subsequent RAB assignments are rejected by RNC

– no multi RABs f2 HSf HS f HSff

RNC

Iub

Iu

HS-DSCHHS-SCCH

HS-DPCCH

Speech call

Please note that..

UTRAN UE

1. RANAP: RAB Assignment Request (CS RAB)

MSC

2. RANAP: RAB Assignment Response

SGSN

PS Interactive 64/HS - HS-DSCH

If the current PS Interactive RB is allocated HS-DSCH resources, the RAB Assignment response includes the unmapped RAB IDs in the “RABs failed to setup or modify” IE.

56

Agenda








Mobility:Mobility:

Intra-HSDPA Intra-HSDPA

Mobility:Mobility:

Intra-HSDPA Intra-HSDPA

57

RNC RNCIur

Iub Iub

Iu Iu


HS-DPCCH

Iub

HSDPA Mobility: introduction (1/3)

• After the cell selection, the network has to guarantee the mobility of the HSDPA users

• Since No Soft/Softer HO exist for HS-DSCH, there will be only one serving cell for the HS-DSCH.

• 2 algorithms are interested in the mobility of HSDPA users in connected mode:– Serving HS-DSCH Cell Change

– A-DCH Soft/Softer HO

58


• The HSDPA mobility will be splitted here in different issues:– Measurement reporting

handling

– Handover for A-DCH

– Serving HSDPA cell change

59


• Note that when the UE is PS Interactive using HSDPA, the MEASUREMENT CONTROL includes only neighbor cells of type intra-frequency and no Compressed Mode is triggered, that means that Inter-Frequency and Inter-RAT Handover are not possible to be performed

• What happens when the mobile move to area without HSDPA coverage?

f2 HS

f1 f1

f2 HS f2 HS

f1

f1 f1 f1

2 layers

f2 HSHS HS ff

f

1 layer

60

Measurement reporting (1/2)

• While user moves in the network, it continues to perfom measurement on the CPICH of the detected cells.

• When a UE is setup on a dedicated channel:

– the SRNC sends a MEASUREMENT CONTROL (some information are broadcasted in the system information on the BCCH channel) orders the UE to start Intra frequency measurement.

– As soon as the triggering conditions are fullfilled, the UE sends a MEASUREMENT REPORT message to the SRNC indicating which event occurred and which among the measured cells fulfilled the event criteria.

61

Measurement reporting

• 4 types of intra-frequency measurements are defined in the 3GPP:– Event 1a: Add cell - A primary CPICH enters the reporting range

– Event 1b: Delete cell - A primary CPICH leaves the reporting range

– Event 1c: Replace cell - A Non-active primary CPICH becomes better than an active primary CPICH

– Event 1d: Change of best cell - A primary CPICH becomes better than the previously best primary CPICH

– Event 1e: A primary CPICH becomes better than an absolute threshold

– Event 1f: A primary CPICH becomes worse than an absolute threshold

• Note that the RNC can configure more than 1 measurement report for the same event.

62

Mobility Example

0 5 10 15-20

-15

-10

-5

0

time [s]

Ec/N

0 [dB

]

cell 1cell 2cell 3

event 1d: Change of best cell, to cell 3

Active set handling:(Max active set = 3)

event 1a: Add cell 2, to the ASAdd cell 3, to the AS

event 1b: Delete cell2

2

1 3

63

Measurement reporting for HSDPA

• When PS Interactive using HSDPA is started, an extra MEASUREMENT CONTROL related only to the event 1d HS , is sent to the UE having another MEASUREMENT ID than the ones dealing with the conventional event 1d for Soft Handover evaluation.

• The reason for having a separate event 1d HS is– to be able to get UE reports triggered by only Active Set cells

– to be able to use different hysteresis and time to trigger parameters to trigger HS-DSCH Cell Change.

– to use a different quality criteria (RSCP of the cells in the Active Set)

• Since the 1d Hs reported cell is already a member of the current Active Set, this event do not trigger any change in the AS.

64

R99R99 R99

A-DCH handover

• In the previous slide it is stated that “there will be only one serving cell for the HS-DSCH”. This does not mean that the UE is connected to only one cell.

• For what concerns the A-DCH they continue to perfrom soft and softer hand-over as in normal R99 case.

• Note that HS-DPCCH can be only in softer HO.

• In the example supposing the best server does not change...

HSHS HS

HSHS HS HS

HS-DSCHHS-DSCHA-DCHA-DCH

R99 HS

65

Serving HSDPA Cell Change (1/2)

• When the UE moves between cells, the HSDPA connection is maintained by means of intra frequency serving HS-DSCH Cell Change.

• HS-DSCH Cell Change evaluation performs the evaluation of a valid target cell within the current Active Set, only towards a “suitable HS-DSCH cell’s”.

• A suitable HS-DSCH Cell is a cell that satisfies the following conditions: – Cell in the current Active Set.

– Internal UTRAN cell.

– Cell having HS-DSCH enabled.

66

Serving HSDPA Cell Change (2/2)

• Serving HS-DSCH cell change is triggered by:– Change of “Best cell” as indicated by receiving an event 1d, UE measurement

report

– Removal of the Serving HS-DSCH cell from the active set due to receiving an event 1b, UE measurement report.

– Removal of the Serving HS-DSCH cell from the active set due to receiving an event 1c, UE measurement report.

– any other reason where the current serving HS-DSCH cell is to be removed from the active set.

• No support for HS-DSCH over Iur: – RRC Directed Signaling Connection Re-establishment

67

Soft/softer HO for A-DCH and cell change for HSDPA channels

Measurement quantity

time

P_CPICH 1

Reporting event 1d-hs

P_CPICH 2 hsdhysteresis 1_

Reporting event 1a

Rep. Range 1a

A-DCH in SHO with cell 1 and 2HSDPA channels cell change from cell 1 to cell 2

Rep. Range 1b

Reporting event 1b

A-DCH on cell 2 only

Initially A-DCH and HSDPA both only on cell 1

Note, there is of course a time-to-trigger also for event 1d-hs

68

R99f2 HS

HS HS

f2 HSf1 HS f1 HS

R99 R99

Serving HSDPA Cell Change

• If a suitable HS-DSCH cell can not be found within the current RNS a RRC connection release is triggered.

• After this a new cell selection can follow:– Another connection establishment with a new Cell selection

– normal connection establishment on R99

– A connection establishment on GSM

f2 HSf2 HS f2 HS

f2 HSHS HS

Ex1

Ex 2

Ex 5

f2 HSf1 HS f1 HS

Cell Selection

Cell Selection

RNC RNC

f2 HS

R99 R99

f2 HS f2 HS

R99R99 R99 R99

Ex3

R99 R99 R99R99 R99 R99

f2 HSHS HS

f2 HSf2 HS f2 HS

GSM GSM GSMGSM GSM GSM

Ex 4

69

Radio Connection Supervision

• Separate parameter hsdschRcLostT determines how long time a HS user can be out-of-sync before the connection is released

• For HS users only the RL in the serving HS-DSCH cell is supervised.– Sync status may change at serving HS-DSCH cell change

Whatever case

f2 HSf2 HS f2 HS


Radio Connection supervision is the algorithm monitoring the synchronization of a mobile, that is, if the mobile is still connected or not.

70

Agenda








71

“Carrier” mobility

• A user conected with a UMTS network on a certain carrier can move out of the its layer coverage.

• There are 2 mechanisms to avoid the drop, at least for some services:

– Inter-RAT Handover

– Inter-Frequency Handover

f2 HS

HS-SCCH

f1 f1

f2 HS f2 HS

f1

f1 f1 f1


GSM GSM

GSMGSM GSM

GSM

• Most of the time anyway the passage between carriers happens in idle mode

72

IRAT/IF Handover in five steps(IRAT HO in the example)

UTRAN

UE moves to poor carrier coverage area and reports to UTRAN

1

UTRAN commands CM measurements 2

UE finds suitable cells in another layer and when coverage is even

worse it reports the candidates3

UTRAN evaluates the candidates and

commands the HO4

UE gets access to the new LAYER5

Core Network

Core Network

GSM/Other Carrier

73

Layer Quality

time

Threshold 2

Threshold 3

Threshold 1

CM

Compressed ModeHO L2

L1

The problem is that there are several thresholds

IF&IRAT Handover: basic

• Main steps– When the quality of the connection overcomes a certain thresholds (event 2d or

6a) UE reports a Measurement report and the network orders the UE to activate the CM and check the other layer.

– If the connection quality further degrades and the other layer has a quality high enough the HO is triggered (events 3a and 2b).

– If the connection quality turns out to be good, the UE signals it to the network and the mobile stops the CM (events 2f or 6b).

74

IRAT & IFHO procedures

• The evaluation process for HO execution depends on the quantity that started measurements (CPM) among:

– CPICH RSCP– CPICH Ec/Io– UE TX power

• At the same time, the cell in the target layer should have the quality good enough. That means:– For GSM: the quality of the measured GSM cells is above a gsmThresh3a.

– For the second UMTS layer: the measured best cell on unused frequency is above both the thresholds nonUsedFreqThresh4_2bEcno and nonUsedFreqThresh4_2bRscp

• Both of the HO are hard HO:– This means that there will be small interruptions in the data flow to and from the

UE.

Evaluated In parallel

75

Initial Cell

Target Layer

CPICH Ec/No

HO trigg

Start CPM

UE TX power

HO trigg

Start CPM

Other layer good enough

CPICH RSCP

Start CPM

HO trigg

CPM start and HO trigger

76

IRAT HO and Cell Change

• Until here, concerning 3G to 2G switch, only IRAT HO has been mentioned. Anyway when the UE is in connected mode with a PS RAB, the switching procedure to 2G is called “IRAT Cell Change”.

• Compared to IRAT HO:

– There is no difference in the evaluation procedure.

– In the Inter-RAT Cell Change case there are no resources reserved in the target cell before the Inter-RAT Cell Change is executed.

– There is significant outage period and a certain number of lost packets when moving toward 2G that have to be carefully evaluated

• (If the Inter-RAT Cell Change is evaluated and executed by the UE in Idle mode or connected mode on common channels it is denoted Cell Reselection or Inter-RAT Cell Reselection, see Idle Mode and Common Channel Behaviour for more details)

77

IF or IRAT?

• A decision has to be made to evaluate either Inter-Frequency handover or Inter-RAT Handover/Cell Change. This decision is based on parameters on RNC level, cell level, and UeRc state.

– Inter-Frequency handover is only attempted if C_IfHoAllowed is set to Allowed for the current UeRc state, and FddIfHoSupp (RNC) is set to On .

– Inter-RAT handover is only attempted if C_GsmHoAllowed is set to Allowed for the current UeRc state, and FddGsmHoSupp (RNC) is set to On.

– If both the conditions are verified the decision is based on a configurable parameter, hoType (cell), defined per cell (IFHO preferred, GSM preferred, None).

• Hence, for a certain cell only one of the 2 Handover types will be allowed.

Where?

f1

f2 HS

f1

GSM

GSM

??

78

• Dimensioning example

CIPICH dimensioning

CPICH power = 0.87 W

In the dimensioning process the power found with CPICH is done in order to guarantee an adeguate CPICH level (Ec/N0 > -16) within the cell area (Range = 1.17 km).

Does that mean that the boundary of a UMTS cell

corresponds to CIPICH_EC/N0 = -16?

79

Which is the real area of a UMTS cell?

• When a GSM network or a second carrier is deployed the question is not easy to be answered.

• Only looking at the Ec/N0 suggested threshold for IF/IRAT HO we note that:

– usedFreqThresh2dEcno = -12– utranRelThresh3aEcno = -1 (relative to 2d thr.) = -13

• Different terminals have different behaviours.

• The load changes the cell border.

80

Impact on coverage

WCDMA RBSArea without CM

CM start Ec/No

HO Ec/N0

CM start RSCP

HO RSCP

CM start Tx Pwr

HO RSCP

New area the cell

81

Notes for HSDPA

• HSDPA users, when in connected mode with a HSDSCH: – will not be allowed to perform IF and IRAT HO.

– will not experience CM.

• Anyway:– they can experiment it when in connected mode with a R99 RAB or in other dedicated

connection.

– They can impact on other users behavior

Don’t forget idle mode!

Users change carrier or network even in idle mode and the coprresponding parameters have to be carefully tuned as well.

82

GSM coverage

GSM only area

IRAT Cell Reselection

WCDMA unacceptable area because of low RSCP

WCDMA unacceptable area because of low Ec/No

WCDMA acceptable area

WCDMA Service

RSCP>qRxLevMin +P

Ec/No>qQualMin

GSM->WCDMA entering area

Ec/No>FDDQMINRSCP>GSM_RLA +FDDQOFF

WCDMA->GSM normal reselection area

RSCP+qHyst1 > GSM_RSSI-qOffset1

Ec/No>qQualMin+sRATsearch

Overall description of thresholds

WCDMA RBS

Unstable areas

83

Agenda








Capacity ManagementCapacity Management

Algorithm Algorithm

Capacity ManagementCapacity Management

Algorithm Algorithm

84

Capacity Management (Overview)

• Capacity Management solution controls the load in the WCDMA cells.

• It includes 3 main algorithms:

Admission Control controls the utilization of dedicated monitored resources by accepting or refusing requests for utilization of these resources

Congestion Control detects overload situations on some dedicated monitored resources and initiates congestion resolve actions to decrease the load

Dedicated Monitored Resource Handling gathers and provides information about the current usage of critical resources

85

Dedicated Resources

• The Dedicated Monitored Resource Handling function collects and provides information about the current usage of resources that are critical to the load of the cell. There are three reasons for blocking:

• RF POWER:

the total transmitted carrier power is constantly monitored by the algorithm. When the value exceeds some configurable thresholds the admission/congestion take decisions for guaranteed and non-guaranteed service class connections

• CODE – Code Usage: the total number of codes is monitored.

– Code Hystogram: the number of codes used for each SF are monitored. The max number of code for each SF is configurable. A control is also done on the maximum number of compressed mode connections

• ASE (Air-Speech Equivalent):This monitor is based on the estimation of the air-interface usage per radio link type (RB type) in a cell. Thresholds can be defined separately for the uplink and downlink, for guaranteed or non-guaranteed connections

86

Admission Control Algorithm

Downlink Transmitted Carrier Power Monitor (for Admission purpose)

35% 75%

85%

default values

• Requests arrive to the AC at several moments:

– Radio Link Setup

– Radio Link Addition

– Radio Link Reconfiguration

– Compressed Mode Command

• Different thresholds exist for different types of request:

– (g,ho) guaranteed, handover

– (g,nho) guaranteed, non-handover

– (ng,ho) non-guaranteed, handover

– (ng,nho) non-guaranteed, non-handover

• The AC accepts requests until a certain threshold on a monitored resource (power in this case) is reached.

87

Congestion Control Algorithm

Downlink Transmitted Carrier Power Monitor (for Congestion control)

Default values:pwrOffset = +5% 90%pwrHyst = 600 ms

• The congestion control has an unique threshold for all the service types (pwrAdm+ pwrAdmOffset +pwrOffset) to regard the cell as “congested”.

• The action to decrease the load in the cell considers instead the different priorities of the services.

88

Traffic Algorithms

• The PS traffic (non-guaranteed) is managed by the RRM algorithms with a lower priority at several levels:– Lower threshold on AC

– First user to be considered for Congestion actions

• Besides RRM algorithms, even the Channel Switching algorithm acts to control the PS traffic.

89

HSDPA Monitored Resource Handling

• The way of measuring the resources has to be adapted to the HSDPA:

– The monitored power in the RNC keeps track only of the usage of total non-HS downlink transmitted carrier power. – The reports of the power measurements are adapted to the capability of a cell:

– HSDPA capable ‘Transmitted carrier power of all codes not used for HS-PDSCH or HS-SCCH transmission’

– HSDPA not capable ‘Transmitted carrier power’

– 2 new dedicated monitored resource is introduced: – the number of HS-serving links in a cell.– The usage of SF 4 in uplink (the usage of the optional PS384/HS radio connection type)

– The measurement of code tree utilization considers the codes allocated for HS-PDSCH and HS-SCCH channels.

90

HSDPA Admission Control Algorithm

• The AC receives requests from a HS users in 2 moments:

– At RAB establishment; in particular after the serving HS-DSCH cell selection.

– For mobility, e.g. A Radio link Addition for A-DCH handover

– No AC is performed within a Cell Change procedure

– Note that there are neither Compressed Mode requests nor Radio Link Reconfiguration

f2 HS

RNC Iur

Iub

Iu


HS-DPCCH

f HS f2 HSR99 R99 R99

1

AC

91

HSDPA Admission Control Algorithm

• The AC performs several types of check:

– A-DCH:– Total available codes (for A-DCH only).– ASE (for A-DCH only).– Power (for A-DCH) – Code with SF=4 in UL (for A-DCH PS 384 in UL)– (Hardware, new in P4)

– HS-DSCH:– Number of HS-serving links (for RAB set up only)

92

HSDPA - Code Control

• There is no check on HSDSCH and HSSCCH codes done by the AC.

• The operator configure and “reserve” the number of HS-PDSCH codes allocated in a cell for HSDPA (numHsPdschCodes)

– Increase lock of the cell and release of traffic

– Decrease no effect on ongoing traffic

• The number of HS-SCCH (SF=128) codes is one

16

8

4

2

1

SF

Common Channels;HS-SCCH

DedicatedChannels

HS-PDSCH (default)

93

HSDPA – Number of HS users

• The operator can limit the number of users that can be allocated to the HS-DSCH cell (hsdpaUsersAdm)

• This limit enables the users allocated to the HS-DSCH (shared channel) to experience a sufficient end-to-end quality

• The new policy is only applied to requests for new HSDPA connections

# users on HS-PDSCH / HS-SCCH

Only serving cellchange of HSDPAadmitted

Request forHSDPA resourcesalways admitted

hsdpaUsersAdm

94

HSDPA –UL Histogram AC

• The operator can set a limit for the ”guaranteed-hs” admission requests demanding spreading factor 4 in uplink that can be accepted (in cells where the PS384/HS is activated)

• The threshold is set according to the parameter sf4AdmUl

• This policy allows the operator to disable the PS384/HS feature on a cell basis

• sf4AdmUl can be reduced if the uplink is experienced as problematic, for example due to high Received Total Wideband Power or transport network problems

95

• New service class, ”guaranteed-hs”, assigned to the A-DCHs

• Highest priority for ”guaranteed-hs” service class in admission decisions to enable HSDPA users to use the excess power in high loaded (non-congested) cells

• Soft congestion is not affected by the introduction of HSDPA

Power

Adm

issi

on G

rant

edR

ejec

t

Adm

issi

on G

rant

edR

ejec

t

Adm

issi

on G

rant

edR

ejec

t

Rej

ect

Adm

issi

onG

rant

edno

n-gu

aran

teed

/no

n-ha

ndov

er

non-

guar

ante

ed /

hand

over

guar

ante

ed /

non-

hand

over

guar

ante

ed /

hand

over

Adm

issi

on G

rant

edR

ejec

tgu

aran

teed

-hs

/ non

-han

dove

r

Adm

issi

on G

rant

edR

ejec

tgu

aran

teed

-hs

/ han

dove

r

pwrAdm + pwrAdmOffset

pwrAdm

pwrAdm – beMarginPwrAdm

pwrAdm + pwrAdmOffset + pwrOffset

HSDPA DL Power Admission

96

HSDPA – “Link” Power Admission

HSDPAWhile the admission control on a ”session” level is performed by the RNC, it is important to take in mind that the RBS ”control” the HS access to the shared resources.

Common channels

Dedicated channels

To

tal

avai

lab

le c

ell

po

wer

97

HSDPA - Congestion Control

tmInitialGtmInitialGhstmCongActionNgRelease non-guaranteed traffictmCongActionGhsRelease guaranteed HS traffictmCongActionRelease guaranteed traffic

Time

Power

Congestion threshold

”guaranteed-hs” service class gets intermediate priority (between ”non-guaranteed” and ”guaranteed”)tmInitialGhs minimum time between start of DL congestions and initiation of congestion resolve action on HSDPA users

All non-guaranteed traffic released.tmCongActionGhs is restarted as tmInitialGhs has not expired.

This policy enforces the higher retention priority of CS services compared to interactive services

tmCongActionGhs time interval between congestion release actions on HSDPA

releaseAseDIGhs amount of ASE to be released at congestion resolve action

98

Agenda








Load Sharing Load Sharing

Techniques Techniques

Load Sharing Load Sharing

Techniques Techniques

99

Load Sharing (1/2)

• Load sharing features pool together resources from different parts of the entire network.

• 2 load-sharing features are available in the WCDMA RAN:

– Inter-Frequency Load Sharing

– Directed Retry to GSM

Both load-sharing features redirect calls during the connection setup phase:RRC connection setup for IF load SharingRAB setup for Directed retry

Both IF HO and Directed retry will be present at the same time but IF will act first!

100

• For load sharing purposes, cell load is defined as the ratio between the downlink transmitted carrier power and the admission limit, as given by the cell parameter pwrAdm.

• The load sharing algorithm acts only when the load of a cell overcomes a certain threshold:– For IF, the threshold is set to 50%

– For directed retry both the threshold and the percentage of users to be redirected can be tuned

Time

Cel

l L

oad

DR

thr

Time

Cel

l L

oad

IF

50%

Cell Load = Tx_power/PwrAdm

Load Sharing (2/2)

For HSDPA cells, only the non-HSDPA part is counted

101

Directed Retry algorithm

• Speech call (without packet connection) is the only service that is targeted since it is also the only one that is safe to divert to GSM

• Directed Retry is performed during the RAB establishment procedure; – the first request will be rejected with cause "Directed retry“

– a request is made to the core network to relocate the UE to a specific GSM cell, using the Inter-RAT handover procedure.

• This handover is a blind HO since the target cell is chosen not based on UE measurements. Therefore, the target cell must be co-located with the WCDMA cell.

There are 2 control parameters:

loadSharingGsmThreshold specifies the minimum cell load at which off-loading to GSM begins.

loadSharingGsmFraction specifies the percentage of Directed Retry candidates to be diverted to GSM

Time

Cel

l L

oad

DR

loadSharingGsmThreshold

102

Inter-Frequency Load Sharing (1/2)

UMTS L2

UMTS L1

GSM

If the target cell is less loaded, the UE will not be instructed directly to go to the target cell but it will be told to scan for a suitable cell in the frequency of the target cell, by sending an RRC Connection Reject message.

3

3

The mobile starts a RRC connection establishment procedure ( NO distinction in RRC cause is made)

1

1

2

If the cell load is higher than 50%, the load of the co-located load-sharing neighbor is compared with the accessed cell and the least loaded cell is chosen as target.

Lo

ad

Cell 2

Lo

ad

Cell 1

> = <

?

2

50%

103

Free Resource = R[2]

Power/pwrAdm

33%

100%

DL power in use 100%

Free Resource

Power/pwrAdm

33%

Second Carrier

First Carrier

L[1] < 50 %-> Don’t do anything


Power/pwrAdm

33%

100%


Free Resource

Power/pwrAdm

60%

Second Carrier

First Carrier

L[1] > 50 %-> Compare the load with the load sharing candidate


Second Carrier

Free Resource

Power/pwrAdm

33%

Free Resource

L[2] = 33% -- L[1] = 60% L[1] > L[2] Select R[2],

Power/pwrAdm

100%

First Carrier

60%


Power/pwrAdm

33%

L[2] = 33% -- L[1] = 60%L[1] - 20% > L[2] Select Second Carrier

100%

loadSharingThreshold (20%)


Free Resource

Power/pwrAdm

60%

To minimize excessive load sharing a hysteresis is used in the comparison,

loadSharingThreshold.

IF Load Sharing

Here an example of comparison between 2 different frequency is reported.

Layer 2

Layer 1

Lo

ad

Cell 2 Lo

ad

Cell 1

> = <

?

104

HSDPA – IF Load Sharing

Second CarrierLayer 2

Layer 1

Lo

ad

Cell 2 Lo

ad

Cell 1

> = <

? 50%

loadSharingMargin is a cell-specific parameter that specifies the amount of resource excluded from load-sharing use (as a percentage of pwrAdm). When loadSharingMargin is greater than 0, the cell appears to be more loaded than it really is, resulting in more traffic being directed away from it

This parameter gives the operator the possibility to reserve a higher priority to the HSDPA users on the second carriers (in case this is deployed and HSDPA is introduced there)


Power/pwrAdm

33%

100%

loadSharingThreshold (20%)

L[2] = 33% + 10% -- L[1] = 60%L[1] - 20% < L[2] 40% < 43%Stay on the First Carrier


Free Resource

Power/pwrAdm

60%

loadSharingMargin (10%)

105

• Apart from the load sharing algorithm, other aspects have to be managed and tuned with the introduction of the second layer:

– Mobility: – IF HO procedure is more critical compared to a normal SHO and has to be

verified and tuned.– The compressed mode activity increases in the border cells.

– Accessibility:– The first IF Load Sharing will increase the call set up time.

– Terminal equipment limitations:– At them moment, there are several terminal types not fully supporting the

features to manage a second layer. In particular several models are not IF HO capable.

Inter-Frequency Load Sharing

106

Agenda








Cell Breathing Cell Breathing Cell Breathing Cell Breathing

107

Coverage vs. traffic load

WCDMA RBS

DL high Load

UL high Load

UL low load

DL low load

A well known effect of WCDMA CPICH coverage is that it changes depending on the load.

The DL coverage (considering the Ec/N0 of the CPICH) in particular decreases with the DL total power (hence with the load).CPICH_Ec/N0 in a point:

Ec/N0Cpich = RSCP/RSSI = Pcpich/( (PtotIntra + Ptotinter + Noise)(*P = received power)

108

Low load CM Area

CM start

IRAT

UL high Load

DL Problem CPICH Ec/N0 triggering

DL high Load

High load CM Area

CM start

IRAT

WCDMA RBS

Expected cell area

109

Agenda








Accessibility KPIAccessibility KPIAccessibility KPIAccessibility KPI

110

Accessibility (CSSR) KPI

The IF Load Sharing feature impacts on the RRC Establishment Success Rate since several RRC Connection Attempts are rejected to be redirected towards the other frequency. So it is expected that, in case of IFLS activated, the number of RRC Connection Success will be reduced because of the Load Sharing Reject events. To take into account this fact the LoadSharingRejects must be subtracted from the total number of RRC_Attempts:

RRC Establishment Success Rate (IFLS) = RRC_Success / ( RRC_Attempts – LoadSharingRejects)

CSSR is currently calculated by two factors:RRC Establishment Success Rate = RRC_Success / RRC_Attempts *RAB Establishment Success Rate = RAB_Success / RAB_Attempts

However the counter for Load Sharing Rejects (pmNoLoadSharingRrcConn) is unique and it does not distinguish between CS, PS or any other kind of RRC Connection cause. This make not easy to adjust the RRC Success Rate for CS and for PS in case of IFLS.

111

Proposed new formulaeHere we tried to evaluate the performance of some formulae to derive the RRC_Estab_Succ_Rate for PS and CS in case of IFLS. (The results are taken from RNC???)

The tested formulae are:

ConnectReqpmTotNoRrcCsConnectReqpmTotNoRrc

nnaringRrcCopmNoLoadSh - CsConnectReqpmTotNoRrc

CsSuccConnectReqpmTotNoRrc __

CSSuccRRC

ConnectReqpmTotNoRrcPsConnectReqpmTotNoRrc

nnaringRrcCopmNoLoadSh - PsConnectReqpmTotNoRrc

PsSuccConnectReqpmTotNoRrc __

PSSuccRRC

The basic idea is to calculate the load sharing reject for PS and CS by a wheight factor given by the fraction of the RRC_CS (or PS) respect to the total number of RRCs. In case of RRC Succ general the formula is muche more simple instead....

nnaringRrcCopmNoLoadSh - ConnectReqpmTotNoRrc

SuccConnectReqpmTotNoRrc __ generalSuccRRC

112

RRC Connection Establishment Success Rate CS and PS in case of Load Sharing

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Days

0%

20%

40%

60%

80%

100%

120%

LoadSharingReject

RRC_SUC_CS_LS

RRC_SUC_PS_LS

Load Sharing Impact on Accessibility (CSSR) KPI - Results

The RRC Succ estimation CS and PS are disturbed by the Load Sharing rejects. We registered strong fluctuations of values expecially in case of high IFLS activity....

113

RRC Connection Establishment Success Rate General in case of Load Sharing

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

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0.0%

20.0%

40.0%

60.0%

80.0%

100.0%

120.0%

LoadSharingEvents

RRC_SUC_LS


In case of RRC Succ Rate calculated for all kinds of RRC, the estimation is much more stable instead and not affected by IFLS!

114

RRC Connection Estab. Succ. Rate comparison (General, CS, PS) including Load Sharing

80.0%

85.0%

90.0%

95.0%

100.0%

105.0%

110.0%

Days

RRC_SUC_LS

RRC_SUC_CS_LS

RRC_SUC_PS_LS


Here it is quite evident the noise introduced by the load sharing in CS and PS RRC Succ estimations.

>100% values

Strong KPI deterioration

Please consider that the values are calculated on daily base. So they should be quite stable

115

Conclusions (1/2)When Load sharing is introduce the accessibility formulae should be updated to take into consideration the RRC Connection Attempts rejected to be redirected towards the other frequency ().While no problem should exist for the tot accessibility formula:

2 new formulae are proposed for the CS and PS specific KPIs:

However the estimation given by this KPI is not extremely stable/reliable and accurate (the average error seems to be acceptable compared to the error that affects the other formulae but the fluctuation are high).

ConnectReqpmTotNoRrcCsConnectReqpmTotNoRrc

nnaringRrcCopmNoLoadSh - CsConnectReqpmTotNoRrc

CsSuccConnectReqpmTotNoRrc __

CSSuccRRC

ConnectReqpmTotNoRrcPsConnectReqpmTotNoRrc

nnaringRrcCopmNoLoadSh - PsConnectReqpmTotNoRrc

PsSuccConnectReqpmTotNoRrc __

PSSuccRRC

nnaringRrcCopmNoLoadSh - ConnectReqpmTotNoRrc

SuccConnectReqpmTotNoRrc __ generalSuccRRC

116

ConclusionsAn alternative suggestion could be to use the following formula for CSSR

CSSR_CS = RRC_Succ_Global x RAB_CS_SuccCSSR_PS = RRC_Succ_Global x RAB_PS_Succ The estimation given by this KPI is much more stable/reliable and the average error seems to be acceptable compared to the error that affects the other formulae.

The main drawback of this solution is that the Global RRC Succ is often a little bit worse compared with the real CS and PS values.

(This is probably related to different radio environment: i.e. the major part of RRC Connections are established for registration purpose, when the UE is entering back to 3G coverage; those radio procedures often occur at cell coverage borders and so are affected by a worse performance.)

117

Agenda







6. Capacity Management6. Capacity Management6. Capacity Management6. Capacity ManagementRBS KPIRBS KPIRBS KPIRBS KPI

118

RBS Counters KPIs

• This appendix reports the main KPIs that could be used for HS testing divided by:– Throughput

– Scheduling Ratio and Transmission efficiency

– CQI/ACK/NACK

– Power

– RBS RSSI

• Note that performing tests with a single HS user in a unloaded network is useful to:– Have specific user information for a user

– Verify counters/KPI meanings and compare them with UE based KPI

119

Throughput Counters

• Counters:– pmSumAckedBits: the number of Media Access Control high-speed (MAC-hs) bits received and

acknowledged by the UE.

– pmSumTransmittedBits: the number of transmitted bits at MAC-hs, level including retransmissions

– pmSumNonEmptyUserBuffers: The number of user buffers containing high-speed data.

– pmNoActiveSubFrames: the number of subframes containing high-speed data transmitted by the RBS.

– pmNoInactiveRequiredSubFrames: the number of empty subframes transmitted even though data is scheduled for priority queue.

• Still not used:– pmAverageUserRate (PDF): The distribution of the average user rate among all users allocated to

high-speed-DSCH in the cell.

120

Throughput KPIs

• DSCH UE Thr. NET = Av. Throughput (PS-HS) without retransmission: Sum(pmSumAckedBits)/(Sum(pmSumNonEmptyUserBuffers)*0.002s)

• DSCH UE Thr. GROSS = Av. Throughput (PS-HS) with retransmission: Sum(pmSumTransmittedBits)/(Sum(pmSumNonEmptyUserBuffers)*0.002)

• DSCH Cell Thr. NET = The MAC-hs throughput on cell level

pmSumAckedBits / (0.002s * pmNoActiveSubFrame)

• DSCH Cell Thr. GROSS = The MAC-hs data rate on cell level

pmSumTransmittedBits / (0.002 s* pmNoActiveSubFrame)

• Cell Thr. NET = The MAC-hs throughput on cell level

pmSumAckedBits / (ROP period)

• Cell Thr. GROSS = The MAC-hs data rate on cell level

pmSumTransmittedBits / (ROP period)

121

Throughput KPIs Values – Live Network

RBS NameRBS

Sector

RBS Sector Carrier

Average Number Of UE In a Queue

DSCH UE Throughput

NET

DSCH UE Throughput

GROSS

DSCH Cell Throughput

NET

DSCH Cell Throughput

GROSS

RBS32601-01 3 1 1 92.32 148.32 194.89 313.11RBS05314-01 2 2 1 164.11 221.32 265.44 357.98RBS37058-01 1 2 1 183.97 202.45 292.65 322.04RBS00003-01 3 2 1 218.77 259.69 218.77 259.69RBS34645-01 2 1 1 242.96 350.73 242.96 350.73RBS01281-01 3 1 1 248.4 405.3 248.4 405.3RBS37058-01 2 2 1 324.44 405.58 324.79 406.02RBS01780-01 1 1 1 352.6 566.15 491.79 789.63RBS00357-01 2 1 1 389 518.5 389 518.5RBS00429-01 1 2 1 399.94 542.16 399.94 542.16RBS37242-01 3 1 1 424.5 500.75 424.5 500.75RBS34375-01 2 1 1.01 449.73 749.43 461.94 769.76RBS01263-01 1 1 1 456.78 565.98 456.78 565.98RBS23074-01 3 2 1 509.66 552.27 509.66 552.27RBS23066-01 2 1 1 518.67 518.67 518.67 518.67RBS04995-01 1 2 1 556.41 648.95 557.03 649.67RBS00370-01 1 1 1 632.88 838.31 632.88 838.31RBS01546-01 2 1 1 652.58 878.57 751.29 1,011.47RBS01281-01 1 1 1 662.62 1,142.64 662.62 1,142.64RBS34375-01 3 1 1 710.73 1,071.00 710.73 1,071.00RBS23025-01 3 1 1.01 734.94 901.09 828.62 1,015.96RBS37058-01 3 2 1 764.56 995.06 817.15 1,063.51RBS00353-01 1 1 1 770.18 1,170.15 775.24 1,177.84RBS34645-01 1 1 1 828.63 1,319.63 933.18 1,486.14RBS23025-01 2 1 1 881.87 1,205.44 913.16 1,248.20RBS05314-01 1 2 1 1,183.36 1,390.58 1,193.88 1,402.94RBS00429-01 2 2 1 1,200.85 1,605.63 1,200.85 1,605.63RBS01164-01 3 2 1 1,285.29 1,503.11 1,285.65 1,503.53RBS01164-01 2 2 1 1,318.85 1,537.49 1,354.04 1,578.52

122

Transmission efficiency KPIs

• MAC Tx efficiency (or Efficiency factor ) =

Sum(pmNoActiveSubFrame )/ (Sum(pmNoActiveSubFrame)+Sum(pmNoInactiveRequiredSubFrame))

• Scheduling Ratio = This KPI simply highlights the percentage of time the HS-DSCH is used

Sum(pmNoActiveSubFrame)*0.002/ (ROP period)

• Transmission ratio = This highlight the percentage of time there is something to transmit. This is a good index on how efficiently the application level can exploit DSCH capabilities

(Sum(pmNoActiveSubFrame)+Sum(pmNoInactiveRequiredSubFrame))*0.002 /

(ROP period)

• Av.# UEs in queue

Sum(pmSumNonEmptyUserBuffers) / ( Sum(pmNoActiveSubFrame)+ Sum(pmNoInactiveRequiredSubFrames) )

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( + )

Transmission Efficiency (1/2)

• The first index to look at when talking about transmission efficiency is the ratio between the used TTI (the one where something is transmitted) and the total #TTI in the test period

Mac Tx Efficiency = 99.05%

Scheduling Ratio = 81.3%

Nothing transmitted

PDU is transmitted

Buffer not empty but PDU not transmitted

Transmission Ratio = 82.8%

( + )

( + )

( + + )

124

Transmission Efficient KPIs Values – Live Network

RBS Name Sector Carrier%

Scheduling Ratio

% Tranmission

Ratio

RBS32601-01 3 1 0.00% 0.00%RBS05314-01 2 2 1.54% 2.49%RBS37058-01 1 2 0.01% 0.02%RBS00003-01 3 2 0.00% 0.00%RBS34645-01 2 1 0.00% 0.00%RBS01281-01 3 1 0.00% 0.00%RBS37058-01 2 2 0.11% 0.11%RBS01780-01 1 1 0.00% 0.00%RBS00357-01 2 1 0.00% 0.00%RBS00429-01 1 2 0.03% 0.03%RBS37242-01 3 1 0.00% 0.00%RBS34375-01 2 1 0.00% 0.00%RBS01263-01 1 1 0.00% 0.00%RBS23074-01 3 2 0.00% 0.00%RBS23066-01 2 1 0.00% 0.00%RBS04995-01 1 2 0.12% 0.12%RBS00370-01 1 1 0.02% 0.02%RBS01546-01 2 1 0.06% 0.07%RBS01281-01 1 1 0.00% 0.00%RBS34375-01 3 1 0.15% 0.15%RBS23025-01 3 1 0.11% 0.12%RBS37058-01 3 2 0.01% 0.01%RBS00353-01 1 1 0.03% 0.03%RBS34645-01 1 1 0.34% 0.38%RBS23025-01 2 1 0.09% 0.09%RBS05314-01 1 2 0.06% 0.06%RBS00429-01 2 2 0.07% 0.07%RBS01164-01 3 2 0.03% 0.03%RBS01164-01 2 2 0.14% 0.15%

125

CQI/ACK/NACK counters

• pmReportedCqi: the Channel Quality Indicators (CQI) reported by the UE in the cell and received by the RBS.

• pmUsedCqi: the CQI, used by the RBS for scheduling the priority queue for the HS-DSCH.

• Within the reportedCQI tables, there is a column called “InvalidCQI”. This counter will be used as well

• pmAckReceived: The number of Acknowledgements (ACK) that the RBS receives from the User Equipment (UE) over the High-Speed Downlink Shared Channel (HS-DSCH).

• pmNackReceived: The number of Negative-Acknowledgements (NACK) that the RBS receives from the User Equipment (UE) over the High-Speed Downlink Shared Channel (HS-DSCH).

126

CQI/ACK/NACK KPIs

• HS-BLER: pmNackReceived /(pmNackReceived + pmAckReceived)

• RtxOverhead = Percentage of the Retransmitted bits over the total

100*(pmSumTransmittedBits - pmSumAckedBits) /(pmSumTransmittedBits)

• CQI specific– Av. Reported

– Av. USed CQI– Delta CQI = Difference between the 2 averaged values above. This is an index of how much “CQI adjustment” acts.

– CQIequalTo0 = Count(CQIreported=0)/Count(CQIreported). This is the main reason of MAC inefficiency

– InvalidCQI = invalideCQI/Count(CQIreported). Not clear what invlid means

• Proposal: (ACK+NACK)/ActiveTTI: still not clear WHAT WE CAN SEE FROM IT

(pmNackReceived+pmAckReceived)/ActiveFrame

127

HS scheduling

The CQI=0 percentage drop to 0.01%, almost nothing.The BLER and the Retransmission rate are almost identical, that means the CQI adjustment has been able to reach the target

Baseline Test 2

Reported BLER [%] 12,6 12,5RtxOverhead [%] 14,8 15,0

Av Reported CQI 10,1 17,0Av Used CQI 9,8 16,5Delta CQI 0,32 0,48(ACK+NACK)/Active [%] 98,68 97,29CQI = 0 [%] 0,79 0,01

The BLER is the ratio between NACK and (ACK + NACK)

The Rtx overhead is the ratio between the transmitted and the acked bits

Delta CQI could be seen as index of the CQI adjustment impact

When 0 is received no transmission will be allowed to the mobile for the following TTI

128

Integrity KPIs Values– Live Network

RBS Name

RBS Sector

RBS Sector Carrier

% HS-BLER

% Rtx Overhead

MAC Transmission Efficiency

RBS23066-01 2 1 0.00% 0.00% 100.00%RBS37058-01 1 2 4.14% 9.13% 62.87%RBS37242-01 3 1 8.85% 15.23% 100.00%RBS23074-01 3 2 9.43% 7.72% 100.00%RBS05314-01 2 2 10.01% 25.85% 61.83%RBS04995-01 1 2 11.74% 14.26% 99.89%RBS01164-01 2 2 12.03% 14.22% 97.41%RBS05314-01 1 2 12.99% 14.90% 99.12%RBS01164-01 3 2 13.28% 14.49% 99.97%RBS01263-01 1 1 13.64% 19.29% 100.00%RBS23025-01 3 1 14.18% 18.44% 89.32%RBS37058-01 2 2 14.34% 20.01% 99.89%RBS00003-01 3 2 15.38% 15.76% 100.00%RBS37058-01 3 2 18.06% 23.16% 93.56%RBS34375-01 2 1 18.24% 39.99% 98.14%RBS01546-01 2 1 18.33% 25.72% 87.02%RBS00370-01 1 1 18.44% 24.51% 100.00%RBS00429-01 1 2 19.62% 26.23% 100.00%RBS32601-01 3 1 21.05% 37.76% 47.37%RBS23025-01 2 1 22.70% 26.84% 96.60%RBS34375-01 3 1 23.36% 33.64% 100.00%RBS01780-01 1 1 23.64% 37.72% 71.70%RBS00429-01 2 2 24.27% 25.21% 100.00%RBS00357-01 2 1 25.00% 24.98% 100.00%RBS34645-01 1 1 27.50% 37.21% 88.80%RBS00353-01 1 1 28.36% 34.18% 99.35%RBS34645-01 2 1 30.77% 30.73% 100.00%RBS01281-01 3 1 33.68% 38.71% 100.00%RBS01281-01 1 1 38.09% 42.01% 100.00%

129

RBS power

• pmTransmittedCarrierPowerNonHs: The transmitted carrier power for all non high-speed codes in the cell.

• pmTransmittedCarrierPower: the transmitted carrier power measured at the TX reference point every 4 seconds.

• Notes:– Every 100 ms the transmitted carrier power for all non high-speed codes in the

cell are sampled. The problem is that there are not necessary data enough to transmit in every slot: hence some kind of “normalization” should be investigated.

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0

0.1

0.2

0.3

0.4

0.5

0.6

TxCarrierPower

R99Power

Tx Power examples (almost 100% of Scheduling Ratio)

CCH power = 1.7 The Max power = 8.7

The power is calculated at the antenna reference point

131

Transmitted Power (2/2)

• The Average Tx power is: – Total Carrier = 4.85 W

– R99 power = 1.63 W

– TotalHS_power = 3.22 W

• Note that the HS power is an estimation of the power transmitted for the HS on average during the test period but it is NOT an estimate of the power that HS required in the cell!– The activity of the HS (when we transmit something) is still low (80%).

– Maybe a more interesting KPI could be: – TotalHS_power/SchedulingRatio*100

= 100*3.22/81.3 = 3.96 W

• It is interesting to notice anyway that even with a single user the MaxTxPower is reached.

132

RBS list of counters

• pmTransmittedCarrierPowerNonHs: The transmitted carrier power for all non high-speed codes in the cell.

• pmTransmittedCarrierPower: the transmitted carrier power measured at the TX reference point every 4 seconds

• pmNoActiveSubFrames: the number of subframes containing high-speed data transmitted by the RBS.

• pmNoInactiveRequiredSubFrames: the number of empty subframes transmitted even though data is scheduled for priority queue.

• pmSumNonEmptyUserBuffers: The number of user buffers containing high-speed data.

• pmSumAckedBits:the number of Media Access Control high-speed (MAC-hs) bits received and acknowledged by the UE.

• pmSumTransmittedBits: Description The number of transmitted bits at MAC-hs, level including retransmissions

• pmReportedCqi: the Channel Quality Indicators (CQI) reported by the UE in the cell and received by the RBS.

• pmUsedCqi: the CQI, used by the RBS for scheduling the priority queue for the HS-DSCH. pmAckReceived: The number of Acknowledgements (ACK) that the RBS receives from the User Equipment (UE) over the High-Speed Downlink Shared Channel (HS-DSCH).

• pmNackReceived: The number of Negative-Acknowledgements (NACK) that the RBS receives from the User Equipment (UE) over the High-Speed Downlink Shared Channel (HS-DSCH). pmAverageRssi: The average Received Signal Strength Indication (RSSI).

133

Agenda







6. Capacity Management6. Capacity Management6. Capacity Management6. Capacity ManagementRNC KPIRNC KPIRNC KPIRNC KPI

134

• The length of time in seconds that a cell is available for Packet Interactive HS service is defined as cell HS availability. in the example, the cell HS availability during 24 hour period is reported.

1) HS cell Availability (24 Hours period)

Cell Availability (1)

100*3600*24

meMan)pmHsDownti meAutopmHsDownti( 3600*24 ch)Av_HS(Hsds

2) percentage of unplanned HS downtime (24 Hours period)

100*3600*24

meAutopmHsDownti (Hsdsch)Av_Auto_HS

3) percentage of planned HS downtime (24 Hours period)

100*3600*24

meMan pmHsDownti Hsdsch)Av_Man_HS(

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New

New

New

Accessibility

• The new and existing cell counters used in the PS RAB establishment procedure are given in the following list:

Counter name

pmNoRabEstablishAttemptPacketInteractive

pmNoRabEstablishSuccessPacketInteractive

pmNoRabEstablishAttemptPacketInteractiveHs

pmNoRabEstablishSuccessPacketInteractiveHs

pmNoOutgoingHsHardHoAttempt

pmNoIncomingHsHardHoAttempt

pmNoHsHardHoReturnOldChSource

pmNoHsHardHoReturnOldChTarget

New/existing

Existing

Existing

New

New

New

The number of attempted RAB establishments for PS Interactive RAB mapped on HS-DSCH (stepped for the selected Serving HS-DSCH cell at RAB establishment and before possible Inter-Frequency HO).

The number of successful RAB establishments for PS Interactive RAB mapped on HS-DSCH.

Number of successful Hard HO for serving HS-DSCH cell selection (in the source cell).

Number of successful Hard HO for serving HS-DSCH cell selection (in the target cell).

Number of failed Hard HO for serving HS-DSCH cell selection and UE connection maintained (in the source cell).

Number of failed Hard HO for serving HS-DSCH cell selection and UEconnection maintained (in the target cell).

136

Accessibility/ IF counters

137

pmNoRabEstablishAttemptPacketInteractiveHs

Accessibility

• PS Interactive Total RAB establishment, success rate =

100 *pmNoRabEstablishSuccessPacketInteractive

(pmNoRabEstablishAttemptPacketInteractive –pmNoOutgoingHsHardHoAttempt + pmNoIncomingHsHardHoAttempt

+pmNoHsHardHoReturnOldChSource- pmNoHsHardHoReturnOldChTarget )

PS Interactive HS RAB establishment success rate =

100 *pmNoRabEstablishSuccessPacketInteractiveHs

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InterFrequency Handover

2) PS Interactive HS Hard Handover incoming success rate 100*

AttemptngHsHardHopmNoIncomi

SuccessngHsHardHopmNoIncomi dIn_SPS_M_HSHar

3) PS Interactive HS Hard Handover return to old channel rate (source Cell) 100*

AttemptngHsHardHopmNoOutgoi

dChSourceHoReturnOlpmNoHsHard rcedOldCh_SouPS_M_HSHar

4) PS Interactive HS Hard Handover return to old channel rate (target Cell) 100*

AttemptngHsHardHopmNoIncomi

dChTarget HoReturnOlpmNoHsHardget dOldCh_TarPS_M_HSHar

1) PS Interactive HS Hard Handover outgoing success rate 100*

AttemptngHsHardHopmNoOutgoi

SuccessngHsHardHopmNoOutgoi dOut_SPS_M_HSHar

5) PS Interactive HS Hard Handover outgoing Lost connection rate

6) PS Interactive HS Hard Handover incoming Lost connection rate

100*AttemptngHsHardHopmNoOutgoi

dChSource)HoReturnOlpmNoHsHardoSuccessingHsHardH(pmNoOutgo -AttemptngHsHardHopmNoOutgoidOut_Lost PS_M_HSHar

100*AttemptngHsHardHopmNoIncomi

dChTarget)HoReturnOlpmNoHsHardoSuccessingHsHardH(pmNoIncom -AttemptngHsHardHopmNoIncomidIn_Lost PS_M_HSHar

139

pmInactivityHsIdle

Retainability

• The new and existing cell counters used for Retainability are given in the following list:

Counter name

pmNoSystemRabReleasePacket

pmNoNormalRabReleasePacket

pmChSwitchFachIdle

pmNoTpSwitchSp64Speech

pmNoSystemRbReleaseHs

pmNoNormalRbReleaseHs

New/existing

Existing

Existing

Existing

Existing

New

New

New

The number of signalling connection releases triggered for PS Interactive RAB mapped on HS-DSCH due to inactivity (Channel Switching Evaluation algorithms request the execution of a switch to idle). The counter is stepped at the reception of RANAP Iu Release Command from CN, for HS channel cell or RANAP RAB assignment Request (when the RAB is released) and the RANAP cause is User Inactivity.

Number of system releases of packet RABs mapped on HS-DSCH in the Serving HS-DSCH cell.

Number of successful normal releases of packet RABs mapped on HS-DSCH in the Serving HS-DSCH cell.

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Retainability

• HS Radio Bearer retainability, drop rate =

100 *pmNoSystemRbReleaseHs

pmNoSystemRbReleaseHs + pmNoNormalRbReleaseHs

Total PS Interactive retainability, drop rate =

100 *( pmNoSystemRabReleasePacket )

pmNoSystemRabReleasePacket + pmNoNormalRabReleasePacket

141

System Utilization

• It is possible to measure HS A-DCH utilisation in terms of code usage and average number of users per cell.

• Two new set of counters shall be implemented. The first set is used to observe the HS A-DCH code utilisation per cell. The KPI indicates the the total number of A-DCH radio bearers established in a cell.

– ( pmSumPsHsAdchRabEstablish /pmSamplePsHsAdchRabEstablish )

• The second set is used to observe the average number of users per cell (hence the number of HS users), which is done by looking only at the best cell:– (pmSumBestPsHsAdchRabEstablish /pmSampleBestPsHsAdchRabEstablish )

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Throughput

143

Throughput

1) Average Throughput for PS interactive HS (RNC Level)

8*nHs4ketDuratiopmTotalPacnHs3ketDuratiopmTotalPacnHs2ketDuratiopmTotalPacnHs1ketDuratiopmTotalPac

etDataHs4pmSentPacketDataHs3pmSentPack etDataHs2pmSentPack etDataHs1pmSentPack PPintHS_I_T

2) Retransmission Rate for PS interactive HS (RNC Level)

3412

etDataHs4pmSentPacketDataHs3pmSentPack etDataHs2pmSentPack etDataHs1pmSentPack1 etPintHS_I_R

PDHsPDHs

RetransHs2etDataInclpmSentPackRetransHs1etDataInclpmSentPack12P DHs

RetransHs4etDataInclpmSentPackRetransHs3etDataInclpmSentPack34P DHs

Where:

3) HSDPA total RLC data Traffic DL [MByte] (RNC Level)

1000000

etDataHs4pmSentPacketDataHs3pmSentPack etDataHs2pmSentPack etDataHs1pmSentPackATA PintHS_I_D

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Retrans rate – live RNC

Object NameRetrans Rate

PS Int HS

RNCCN1 99.63%RNCKS1 99.49%RNCKS2 100.00%RNCNY1 98.03%

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Mobility

• For mobility only the HS serving cell change procedure is considered .

Counter name

pmNoHsCcSuccess

pmNoHsCcAttemptt

New/existing

New

New

The corresponding KPI is1) Success rate for HS Cell Change in target cell

Note that no AC is requested in the cell change procedure

100*mptpmHsCcAtte

esspmHsCcSucc SPS_M_HSCC_

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Admission & Congestion Control

• Number of of radio links that are on SF=4 in UL– pmSumSf4Ul /pmSamplesSf4Ul

• RNC counter monitoring no. of admission rejects (RAB setup) of HSDPA users– pmNoOfNonHoReqDeniedHs

• RNC counters monitoring no. of HSDPA users (connections) released due to congestion– pmNoOfTermHsCong & pmNoOfIurTermHsCong

HSDPA Principles

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