Master’s Thesis: Case Studies of Network Planning for Wireless Broadband Services – HSDPA and WiMAX Author: Simo-Ville Hönö Supervisor: Prof. Riku Jäntti.

Master’s Thesis:

Case Studies of Network Planning for Wireless Broadband Services

– HSDPA and WiMAX

Author: Simo-Ville HönöSupervisor: Prof. Riku JänttiInstructor: M.Sc. Ilmo Toivonen

© Omnitele Ltd. 2007 2

Outline of Presentation

• Objectives of the Thesis• Case 1: HSDPA

– Introduction to HSDPA

– Planning and optimizing WCDMA networks with HSDPA

– Research methodology

– Analysis of Results

• Case 2: WiMAX– Basics of WiMAX

– Mobile WiMAX Coverage prediction through simulation

• Conclusions


Thesis Objectives

The increasing demand for wireless broadband services are calling for highercapacity, data performance and Quality of Service (QoS) requirements in existingmobile networks (i.e. higher bit rates, lower delays with short round trip times, QoSdifferentiation, seamless mobility and capability for instantaneous voice and data.)

This Thesis is about:

• To point out the new features in network planning as well as system simulation methodology when implementing WCDMA networks with HSDPA, and to provide general aspects and complementary model for further HSDPA simulations using radio network planning tool.

• To provide viewpoints of upcoming Mobile WiMAX coverage planning in urban area, and to illustrate the enhancement in coverage when implementing pico base stations.


Case 1: Introduction to HSDPA

New features in 3GPP Release 5:• High-Speed Downlink Shared Channel (HS-DSCH)

with two additional control channels

• Multi-code operation– Fixed spreading factor of 16

• Adaptive modulation and coding– QPSK + 16QAM

• Flexible scheduling and fast link adaptation– TTI of 2 ms

• Hybrid Automatic Repeat reQuest (HARQ)– Fast and soft retransmission combining at Node B

1 2 31


Planning and optimizing WCDMA networks with HSDPA (1/2)

• HSDPA utilizes the power that is left from Rel99 traffic and shares power and code resources dynamically→ HSDPA NW planning is strongly related to Rel99 NW planning→ The performance of both NWs depend from each other→ Resource allocation (codes and powers), mobility management,

admission and load control (noise rise) as well as QoS decisions must be treated carefully

• Some principles of HSDPA planning:– Clear and homogenous cell dominance areas– Electrical antenna downtilting– Uniform BTS heights with narrow beam antennas– Hot-spots should be preferred


Planning and optimizing WCDMA networks with HSDPA (2/2)

• Network performance analysis– Quality of Experience, Key Performance Indicators (KPIs) and network

parameters

• Channel Quality Indicator (CQI)

• Geometry factor (= own-to-other-cell interference)

QoE KPIs measuresService accessibility

-Availability & coverage -Access success time -Service access delay

Ec/N0, RSCP, admission control, attach, PDP context activation, call setup success ratio

Service integrity

-Video & Audio quality -Web page download time -E-mail sending time

BLER, FER, throughput, average response time, end-to-end delay, jitter

Service retainability

-Dropped connections -Timeouts

Dropped PDP context/attach, coverage outage, handover success ratio, call drop rate


Research methodology

• Radio network planning tool, ASSET3G– Used for network simulations in the planning area

• Monte Carlo simulator taking 100 snapshots per test case

• Nokia N95 Handy– Field test measurements

• empirical data collected from drive test route

• Nemo Analyzer– Analysis of measurement data

The purpose was:1. to validate and verify the simulation methodology through

empirical measurements from existing HSDPA network. 2. to find out the impact of network parameters on data

performance.


Analysis of results (1/5): RSCP

The most of RSCP is between -100 and -65 dBm.

-simulation -field test


Analysis of results (2/5): Ec/N0


The most Ec/N0 is from -3 to -9 dB


Analysis of results (3/5): CQI and Ec/N0 vs. RSCP

96,2 % of all CQI values were above the threshold of 10, which is required for adequate radio conditions

Using the thresholds: RSCP > -95 dBm and Ec/N0 > -15 dB, 81,6 % of all measured values are providing adequate signal quality


Analysis of results (4/5): MAC-hs Throughput

Throughput: 40 HSDPA & 400 Rel99 terminals

0,00%10,00%20,00%30,00%40,00%50,00%60,00%70,00%80,00%90,00%

100,00%

019

238

457

676

896

011

5213

4415

3617

28

bit rate (kbps)

cove

red

are

a

Cov.prob 90%

Cov prob 50%

Cov.prob 90% -cumulative

Cov prob 50% -cumulative


The mean throughput was approximately 731 kbps using 90 % coverage probability and 770 kbps with the probability of 50 %.


Analysis of results (5/5): correlation analysis

• Ec/N0 vs. RSCP vs. throughput • CQI vs. SIR vs. throughput

The highest throughput is achieved with relatively good CQI (17 to 22) and with SIR > 3 dB

Ec/N0 values between -5 and -8 dB with adequate RSCP (> -85 dBm) provide highest throughput


Test case: extra load in serving HS cell

Two additional HSDPA users downloading content in the cell

• Ec/N0 vs. RSCP vs. throughput • CQI vs. SIR vs. throughput

Throughput is spread on Ec/N0 values between -6… -11 dB with RSCP > -100 dBm.

The highest throughput is achieved with SIR > 2 dB.


Case 2: Basics of WiMAX

IEEE 802.16e-2005 specifies WiMAX with mobility:• OFDM

– Transmitting data using subcarriers

• Subchannelisation– PUSC/FUSC

• Smart antenna technologies– Enhance coverage and channel throughput by taking advantage of

multipath through diversity and combining techniques

• MAC layer features– Connection orientated architecture explointing all-IP core NW


Mobile WiMAX Coverage prediction through simulation

• The purpose of the coverage simulations was to illustrate the benefit of applying pico base stations to existing WiMAX macro coverage.

- Macro coverage - Enhanced coverage


Analysis of AMC in WiMAX

• Using outdoor coverage probability of 95 % the achievable downlink bearer was simulated i.e. setting the targeted service level ranging from QPSK 1/2 giving the best obtainable coverage, to 64QAM 5/6 giving the best throughput with the expense of smaller cell size.



64QAM in Mobile WiMAX radio plan


• It was also discovered, how the apply of pico base stations affect on the availability of 64QAM modulation


Conclusions (1/2)

• Case 1: HSDPA– Analysis of measurements and comparison with simulation results

showed that ASSET3G modeled HSDPA network performance fairly accurately, but slightly overestimated the user experienced QoS in some spots according to particular KPIs.

– Simulation parameters like HSDPA transmission power, resource activity factor, applied scheduling method, definition of terminal types together with traffic estimation are the main variation factors.

– the highest bit rates seemed to be most available in favorable radio channel conditions where RSCP > -95 dBm and Ec/N0 > -11 dB.

– HSDPA cell throughput depends strongly on the interference distribution across the cell.


Conclusions (2/2)

• Case 2: Mobile WiMAX– Gaps in fixed WiMAX outdoor coverage were filled and service area

was enhanced significantly when picos were applied

– 16QAM provided almost full coverage in simulation area

– 64QAM can be exploited well in hot-spots

– When implementing Mobile WiMAX NWs with picos, also economical perspective should be considered i.e. transmission and HW costs.

– WiMAX will challenge HSDPA in future network implementations by local telephone companies.


Questions?

Master’s Thesis: Case Studies of Network Planning for Wireless Broadband Services – HSDPA and WiMAX Author: Simo-Ville Hönö Supervisor: Prof. Riku Jäntti.

Documents

network simulations

hsdpa simulations

wcdma networks

simulationconclusions

preferred omnitele

coverage outage

data performance

existingmobile networks