UMTS Network Planning and HSDPA Theory Optimization Procedures.pptx

UMTS NETWORK PLANNING

Self-interference of UMTS System

3x3 reuse of cell

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FDMA / TDMA

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UMTSUMTS system is self-interfered• Source of self-interference

Sharing frequency spectrum, multi-path transmission， spreading code and scrambling code not ideally orthogonal, not ideal planning …

• Self-interference phenomenonPower rise, soft capacity…

• SolutionPower control, admission control, load control, fine planning

The target of UMTS network planning is to minimize the system interference through a reasonable method

Quantity of Subscriber

Quantity of Subscriber-- The Total Bandwidth Received by Node B

The

Tota

l Ban

dwid

th P

ower

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eive

d by

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e B

(dBm

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Power Rise

46 48 50 52 54 56 58 60 62 64

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user number

Tx P

ower

(dB

m)

Common CH.

2 users1 user

3 users...

DL PWR

UL noise rise increase with user number non-linearly

DL Node B power increase with user number non-linearly

UMTS Soft Capacity

interference

UMTS Soft Capacity Breathe effect of UMTS cells

UMTS system capacity decided by not only hardware configuration, but also the system interference level In UMTS system, capacity， coverage， quality are coupled, need a trade off during the planning

Cell breathe embodies the influence of cell load to cell coverage

UMTS System DL /UL Coverage and Capacity

135

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100 200 300 400 500 600 700 800 900 1000 1100 1200 1300Load per sector [kbps]

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Better coverage

DL load

UL load

Normally,Coverage is UL limitedCapacity is DL limited

Capacity couples with coverage；DL /UL coverage relationship decided by system load

Power Control

• Signal for one user is noise for others. Power should be controlled at a reasonable level to keep good quality but not cause interference to others.

• Near－ far problem– Signal from UEs near Node B

can easily drown the signal of UEs at the edge of cell.

– Received power for all UE should be kept at same level, the noise in cell be optimized.

– Power control period is 0.66 ms (1500 Hz)

De-spread

Near far effdct

Node B

De-spread

Power control

Node B

TPC is basis

Tx Pwr Minimized

Enhance systemcapacity

Soft Handover

• UE at cell edge can receive signals from multiple cells

• Under control of RNC, UE can receive information from several cells, each DL use different scrambling code

• Softer handover– Communication with two cells

of same Node B• Soft handover

– Communication with two or more Node Bs

• Hard handover (inter frequency)– UE switch to different

frequency

Hard Handover

Soft Handover

Tasks and Target for Network Planning

To satisfy the requirements from operator on coverage, capacity demand, and service quality, by performing the network dimensioning, design and simulation, so that the maximized benefits can be gained from the network. Network planning should have a prediction of future development, and be ready for future construction.

Tasks

Achieves the good coverage to the most extent in terms of time and location.

Minimize system self-interference to the most extent so as to get the desired quality.

Optimize radio parameters to get the best of system performance.

With the precondition that capacity and quality requirements are met, reduce the hardware expenditure and system total cost.

Target

UMTS network planning FlowRequirement analysis

Dimensioning

Pre-planning simulation

Site survey

Site evaluation

Topology design

Simulation

Propagation model test

Propagation model tuning

Parameter planning

Requirements satisfied

Output planning report

• Power allocation for DL channels• scrambling code planning• Handover parameter planning• Frequency allocation

Flow－ parameter planning

Good, Effective Coverage

Driven by traffic, classify target coverage area

Classify plan area type according to propagation model and traffic density

Different plan area has different target of coverage

Make clear traffic coverage requirement for different coverage area

Effective Coverage Principle

Voice 12.2 kbps Data 64 kbps Data 384 kbpsBTS

Continuous coverage for basic service

Important area provide with high speed service coverage；Certain level of indoor coverage

Certain level of pilot strength and quality for coverage area

Flexible usage of series of NodeB and coverage enhancing technology

Good Coverage Principle

HSDPA THEORY & OPTIMIZATION PROCEDURES

• HSDPA is R5 technology for WCDMA• HSDPA is a new technology to enhance WCDMA PS data services• User experience in HSPDA is improved due to higher speed & shorter

delays• HSDPA evolved from WCDMA R99 without any big effect to the existing

R99 network • HSDPA uses shared channels & there is no soft HO In this technology.

HSPDA only support hard HO same as LTE• HSDPA can support 64 subscriber/cell. This is the theoretical limit for

subscriber• HSDPA support more users while providing higher data rates• HSDPA monitoring should be focused on capacity (power/code usage) &

PS performance (throughput)

HSDPA Introduction

• HSDPA is fully compatible with R4 layer 1 & layer 2 with the introduction of MAC entity (MAC – hs) in the Node B

• MAC – hs at NodeB end is in charge of scheduling / repeating the data on a new physical channel (HS- DSCH) shared between all users

• MAC – hs provides the following functionalities1. Adaptive modulation & coding based on CQI measurements2. New transport channel high speed DL shared channel (HS-DSCH)3. Fast scheduling through HARQ, re-transmission & allocation of radio link• SF used for HSDPA is 16 but one channel/code is dedicated for P-CPICH &

PCCPCH yielding 15 codes / channels for subscriber usage• Maximum throughput / data rates in HSDPA can be achieved is 14.4Mbps• HSDPA uses 16 QAM & QPSK modulation schemes• Calculation for 14.4Mbps 3.84M/16*4*15 = 14.4Mbps• In HSDPA 1 frame = 2ms TTI & consists of 3 timeslots

HSDPA Theory

• HSDPA uses 1 new transport & 3 new physical channels for efficient communication

1. New transport channel: HS-DSCH2. 3 new physical channels: HS-PDSCH, HS-SCCH & HS-DPCCH3. Introduction of MAC – hs sub layers at NodeB end• HS-PDSCH is used to send DL data• HS-SCCH is used to send DL control information relative to HS-PDSCH &

HS-DPCCH to receive UL control information• New channel coding chain for HS-DSCH transport channel & HS-SCCH

physical channel • HSDPA delay is smaller because of small frame structure (TTI = 2ms) &

communication is from UE to NodeB• With consideration of Network planning & deployment cost, HSDPA

should be applied at the beginning or atleast the NodeB hardware should be ready for HSDPA

HSDPA Theory

HSDPA Architecture

• Following performance domains should be considered

• Accessibility: What is the success rate for HSDPA RB to access the network resources?

• Retainability: What is the success rate for HSDPA RB to end normally? How long time the HSDPA RB can remain without dropping in a cell ?

• Mobility: What is the mobility success rate for HSDPA RB?

• Capacity: HSDPA could consume high network resources capacity (e.g. high power usage)

• Quality: What is the throughput provided based on radio quality and limitations?

HSDPA KPIs

• HSDPA accessibility contains four phases1. RRC connection establishment2. SCCP connection confirmed3. Security Mode completion4. RAB establishment

HSDPA Accessibility

• The Fair Sharing feature is divided in two algorithms: one algorithm atRNC level managing the HSDPA CAC and one algorithm at Node B level managing the OVSF code tree. The two algorithms need to be activatedtogether in order to have a correct behavior:• Flag(RNC; NodeB) = (True; True) =• (isHsxpaR99ResourcesSharingOnCellAllowed;

hsdpaCodeTreeManagementActivation)• From the RNC point of view, when

isHsxpaR99ResourcesSharingOnCellAllowed = True:• At cell setup, the RNC sends to the Node B a PSCR message with the HS-

PDSCH code configuration that the mac-hs scheduler has to use. This PSCR message considers that 15 HS-PDSCH codes can be used by the mac-hs scheduler.

• The RNC considers that all the codes not used by R99 or reserved for HSDPA are free.

• At cell setup, only ccc are reserved (no R99 and HSDPA call).• No other PSCR message is sent after cell setup.• From the Node B point of view, when

hsdpaCodeTreeManagementActivation = True:• At cell setup, the Node B receives from the RNC a PSCR message. The

number of HS-PDSCH codes configured according to this PSCR depends on the RNC

• After the cell setup, the number of HS-PDSCH codes available by the scheduler is updated according to the R99 admission or release thanks to the Fair Sharing algorithm.

• If a new PSCR message is received the scheduler will use this information to know how many HS-PDSCH codes are available.

RAB Matching & CAC

VS.RadioBearerSetupRequest #1652: the number of Radio Bearer establishments to be performed followinga valid RAB assignment request received from the CN. This measurement provides the number of RBs to be setup before CAC is carried out. Sub-Counter #15: HSDPA/R99 Sub-Counter #16: PS I/B or PS Str HSDPA/E-DCH Sub-Counter #19:PS I/B QCHAT HSPA

VS.RadioBearerSetupSuccess #1650: the number of successful Radio Bearer establishments. Thismeasurement provides the number of successful RB setups. Sub-Counter #15: HSDPA/R99 Sub-Counter #16: PS I/B or PS Streaming HSDPA/E-DCH Sub-Counter #19:PS I/B QCHAT HSPA

VS.RabEstablishmentSuccessPerGrantedRabType #1658: the number of successful RAB establishments pergranted RAB type. This measurement provides the number of successful RAB establishments per RAB type asgranted by the UTRAN. Sub-Counter #0:Other Dl, Ul, Traffic Class combinations Sub-Counter #4:Dl is any low rate PS I/B, Ul is any PS I/B, TC is Interactive Sub-Counter #5:Dl is any low rate PS I/B, Ul is any PS I/B, TC is Background Sub-Counter #6:Dl is any high rate PS I/B, Ul is any PS I/B, TC is Interactive Sub-Counter #7:Dl is any high rate PS I/B, Ul is any PS I/B, TC is Background Sub-Counter #12:Dl and Ul are PS I/B QCHAT HSPA, TC is Interactive

RAB Assignment Success

• If Fair Sharing is disabled 1. The only admission control done for HSDPA RAB is based on the

maximum number of simultaneous users allowed2. An HSDPA RB can not be rejected by RNC due to lack of network

resources (Power, OVSF codes etc.)3. In case of CAC failure the feature HSDPA to DCH fallback allows to

setup the RAB using DCH RAB instead of HS-DSCH RAB

• If Fair Sharing is enabled 1. An admission control is performed on:a. DL OVSF codesb. DL powerc. In case of CAC failure on these shared resources , The HSPA to DCH

fallback is not allowed

CAC Dependencies

HSDPA Accessibility Indicator

HSDPA Retain-ability indicator

HSDPA Call Drop Per Minute Of Call

Call Drop Due To UTRAN Generated Reasons

HSDPA Retain-ability Indicator

HSDPA to non-HSDPA & non-HSDPA to HSDPA mobility


• Traffic Segmentation feature allows to deal with a multi-layer scenario where HSDPA is available in only one of the layers.

• Mobiles in idle mode will select a layer according to radio conditions criteria. The cell selection/reselection algorithm is not governed by HSDPA availability so it is not possible to guarantee that an HSDPA mobile will select the HSDPA layer (and vice versa a non-HSDPA mobile will select the non-HSDPA layer).

• Segmentation is done by the RNC when a mobile tries to establish an RRC connection. It is based on the Access Stratum Release Indicator IE present in RRC Connection Request, knowing that R4 mobiles do not support HSDPA.

• If an R4 mobile sends its connection request in the HSDPA layer, it is redirected to the non-HSPDA layer in the RRC Connection Setup message. If an R5 (or later release) mobile sends its connection request in the non-HSDPA layer, it is redirected to the HSDPA layer.

HSDPA Mobility Indicator

Non-HSDPA to HSDPA mobility


The power used for HSDPA shall be evaluated in order to estimate if the power is a limitation resource to reach the target HSDPA throughput

VS.RadioTxCarrierPwr - #10205Average value of the total transmitted power - at the Tx channelizer - for each cell (i.e. per sector and per frequency). The cumulated value at the end of the observation period and the number of samples are provided. The minimum and maximum powers during the reporting period are also provided.Screening: Sub-Counter #0: Operational Max Power Sub-Counter #1: Power used

VS.HsdpaHSPDSCHTxPwr - #10801Total transmitted power on all allocated HS-PDSCH codes per TTI.VS.HsdpaHSSCCHTxPwr - #10803Total power on all transmitted HS-SCCH codes per TTI.

HSDPA Capacity Indicator

HSDPA CODE & USER INDICATORS

VS.HsdpaHSPDSCHCodesPerTTI - #10802:Number of HS-PDSCH codes used per TTI.VS.HsdpaHSSCCHCodesPerTTI - #10804:Number of HS-SCCH codes used per TTI. It then indicates the number of scheduled UEs in the TTI.VS.HsdpaTTIsUsed - #10818:Number of TTIs containing at least one scheduled UE.VS.HsdpaUEsPerHBBU - #10820:Number of UEs configured in the H-BBU.VS.HsdpaUEsPerLCG - #10821:Number of HSDPA UEs configured in the LocalCellGroup.As HsdpaUEsPerLCG counter is reported per LCG and an xCEM is able to manage 2 LCGs, the sum of the 2 LCGshas to be done to get entire xCEM board information.

HSDPA Capacity Indicator

VS.HsdpaMACdPDUAckBits - #10806Total number of successfully transmitted MAC-d PDU bits (an ACK has been received for the corresponding transport block)

VS.HsdpaTTIsUsed - #10818Number of TTIs containing at least one scheduled UE. It allows new statistics to be derived for some previous counters

VS.HsdpaTxDataBitsMAChs - #10808Total number of data bits (transport block size) first transmitted by the MAC-hs. The retransmissions are then not taken into account, meaning that a block retransmitted several times is only taken into account once at the first transmission

VS.HsdpaTxDataBitsSchedTotal - #10809Number of data bits (transport block size) scheduled any TTI, taking into account the retransmissions. Anytime a block is retransmitted, its bits are added.

HSDPA CELL THROUGHPUT

HSDPA Quality Monitoring

VS.HsdpaTxDataBitPerUEcat - #10826:Number of transmitted bits, per UE category (only first transmissions are considered).distribution according to the UE category Sub-Counter #0: For UE category 1 Sub-Counter #1: For UE category 2 ...... Sub-Counter #16: For UE category 17 Sub-Counter #17: For UE category 18VS.HsdpaTTIperUEcat - #10825:number of TTIs for which there is data to be transmitted, per UE categorySame screenings as for #10826VS.DedicatedDownlinkRetransmittedPdusRlcReferenceCell - #1559:Number of downlink RLC PDUs retransmitted on the reference cell. This counter is not applicable to CS Radio Bearers (only applicable to AM RBs). Sub-Counter #5: PS HSDPAVS.DedicatedDownlinkPdusRlcReferenceCell - #1558:Number of RLC PDUs sent downlink for the reference cell. Sub-Counter #5: PS HSDPA

HSDPA UE THROUGHPUT, BLER


VS.HsdpaNbrACKRcv - #10810Number of acknowledged transport blocks ('ACK' received for a transmitted transport block).Remark: ACK + NACK + DTX = Total number of transmitted transport blocks.

VS.HsdpaNbrNACKRcv - #10811Number of negatively acknowledged transport blocks ('NACK' received for a transmitted transport block)

VS.HsdpaNbrDTX - #10812Number of DTXs detected (neither 'ACK' nor 'NACK' received for a transmitted transport block).

HSDPA HARQ FEEDBACK ACK/NACK/DTX


DISTRIBUTION OF RECEIVED CQIs:Metric definition: Distribution of Received CQIs from 0 to 9= #10819.[0-9]/ #10819 Distribution of Received CQIs from 10 to 14= #10819.[10-14]/ #10819 Distribution of Received CQIs from 15 to 17 = #10819.[15-17]/ #10819 Distribution of Received CQIs from 18 to 20 = #10819.[18-20]/ #10819 Distribution of Received CQIs from 21 to 22 = #10819.[21-22]/ #10819 Distribution of Received CQIs from 23 to 25 = #10819.[23-25]/ #10819 Distribution of Received CQIs from 26 to 30 = #10819.[26-30]/ #10819 Distribution of Received CQIs not detected = #10819.[31]/ #10819The distribution of received CQIs will depend only on radio conditions. When the distribution of Received CQIsbelow 15 is important, then the HSDPA Throughput is highly impacted.

HSDPA CQI


U10851_0: VS_HsdpaTrafficModType_QPSK• HSDPA traffic used per modulation type.• Screening: Traffic on QPSK• Trigger: Every 2 ms TTI• 3GPP Counter: VS.HsdpaTrafficModType.QPSKU10851_1: VS_HsdpaTrafficModType_16QAM• HSDPA traffic used per modulation type.• Screening: Traffic on 16QAM• Trigger: Every 2 ms TTI• 3GPP Counter: VS.HsdpaTrafficModType.16QAMU10851_2 : VS_HsdpaTrafficModType_64QAM• HSDPA traffic used per modulation type.• Screening: Traffic on 64-QAM• Trigger: Every 2 ms TTI• 3GPP Counter: VS.HsdpaTrafficModType.64QAM

HSDPA MODULATION


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UMTS Network Planning and HSDPA Theory Optimization Procedures.pptx

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