The Impact of Indoor Traffic on the Performance of WCDMA HSDPA Within Macro Cells

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The Impact of Indoor Traffic on the Performance of WCDMA HSDPA Within Macro

Cells

Author: Mathias NymanSupervisor: Prof. Sven-Gustav HäggmanInstructor: Kimmo Hiltunen, Lic.Sc.(Tech.)

Top right corner for field-mark, customer or partner logotypes. See Best practice for example.

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© LMF Ericsson 2006 2006-01-102

Contents

1. Background, Research Objectives and Methods

2. Basics of HSDPA

3. Simulated Environment and HSDPA Parameters

4. Simulations and Results

5. Conclusions


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Background and Objectives

HSDPA starting to appear in 3G networks

Coverage is a crucial factor for success – macro cell coverage in the first place

Fraction of indoor packet data users is estimated to be 70% in the future building penetration loss

The aim of this thesis is to study how the network performance is affected by the indoor traffic

Research methods: Litterature study (HSDPA and propagation models) and computer simulations


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Contents


2. Basics of HSDPA



5. Conclusions


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Basics of HSDPA

Channelization codes allocatedfor HS-DSCH transmission

8 codes (example)SF=16

SF=8

SF=4

SF=2

SF=1

Shared Channel Transmission– New HS-DSCH Transport Channel– Dynamically shared power and code

resource

TTI

Shared channelization

codes


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Basics of HSDPA

Shared Channel Transmission– New HS-DSCH Transport Channel– Dynamically shared power and code

resource

HS-DSCH

Common channels (not power controlled)

Dedicated channels (power controlled)

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Basics of HSDPA

Shared Channel Transmission– New HS-DSCH Transport Channel– Dynamically shared code resource

Adaptive Modulation and Coding– Data rate adapted to radio

conditions– 2 ms time basis


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Basics of HSDPA

Adaptive Modulation and Coding– Data rate adapted to radio

conditions– 2 ms time basis

Hybrid ARQ– Soft combination of multiple

attempts

Shared Channel Transmission– New HS-DSCH Transport Channel– Dynamically shared code resource

Fast Scheduler– 2 ms time basis– Round Robin, Proportional Fair or Max-C/I


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Contents


2. Basics of HSDPA



5. Conclusions


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Simulated Environment Seven 3-sector sites, wrap-around

Both outdoor and indoor users

COST-WI propagation model

Shadow fading std: 10 dB

Multipath channel: 3GPP Typical Urban

Position dependent building penetration loss

Only HSDPA traffic


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HSDPA Parameters

Modulation: QPSK / 16QAM

HS-PDSCH codes: 10

Scheduling Policy: Proportional Fair

GRAKE Receiver

Traffic type: Interactive, 200kB data packets


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Contents


2. Basics of HSDPA



5. Conclusions


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Impact of Indoor Users Building penetration causes

the A-DCH power to be increased

HS-power is also attenuatedlower CIR

Increased transmission delay

HS-DSCH

Common channels (not power controlled)

Dedicated channels (power controlled)

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Power distribution (non-HS channels)

Very little power reserved for the non-HS channels when most of the users are located outdoors

As the fraction of indoor users increase, more power is used by the non-HS channels.


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Active A-DCHs per cell

As the fraction of indoor users increase, there will be more simultaneous active links per cell

Note that the number of available A-DCHs is 84 in these simulations


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Network performance for different fractions of indoor users The network performance is

clearly decreasing as the fraction of indoor users increase.


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Floor height gain

The performance is worse for the ground floor users (dashed lines) due to the floor height gain.

Ground floor users are exposed to ~14.5 dB more path loss than the top floor (6th floor) users.


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Indoor margin

The system performance is presented for different path loss values when all users are located outdoors

An additional path loss of 19 dB corresponds to the performance of the case with an indoor user fraction of 75%.

Appropriate ”indoor margins” can be taken into account if the amount of indoor users can be estimated.


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Contents


2. Basics of HSDPA



5. Conclusions


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Conclusions

Larger fraction of indoor users decreased network performance

Estimation of the indoor usage will help when designing the network (indoor margin).

A cost-effective macro cellular solution will be suitable in the initial phase, dedicated indoor systems etc. will be required later

Further study: Real network measurements including other traffic than HSDPA, follow-up on HSDPA usage (share of total traffic, amount of indoor usage, etc.)

Documents

The Impact of Indoor Traffic on the Performance of WCDMA HSDPA Within Macro Cells