Microcell Urban Propagation Channel Analysis Using Measurement Data - - PowerPoint PPT Presentation

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Microcell Urban Propagation Channel Analysis Using Measurement Data Mir Ghoraishi Jun-ichi Takada Tetsuro Imai Tokyo Institute of Technology NTT DoCoMo Inc. Takada Lab - TokyoTech 1 Urban Channel Models Usually considers wall

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SLIDE 1

Microcell Urban Propagation Channel Analysis Using Measurement Data

Mir Ghoraishi Jun-ichi Takada Tetsuro Imai Tokyo Institute of Technology NTT DoCoMo Inc.

Takada Lab - TokyoTech 1

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SLIDE 2

Urban Channel Models

  • Usually considers wall reflections, roof-top

diffractions and building edge-diffractions as the major existing propagation micromechanisms.

  • For big macrocell scenarios gives a good

approximation for the channel characteristics.

  • For smaller microcell scenarios in the dense areas

may not be adequate.

Takada Lab - TokyoTech 2

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SLIDE 3

Propagation Prediction Tools

  • Ray tracing algorithms have been reported to

have poor performances due to considering

  • nly simple propagation mechanisms e.g.

specular reflections.

  • Existence of some objects like fences,

signboards, etc. has caused severe degradation

  • f these tools performances.

Takada Lab - TokyoTech 3

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SLIDE 4

Objective

  • To investigate propagation micro-mechanisms

in urban areas.

  • To find the significant scatterers – reflectors.
  • To investigate objects (other than building

walls) involving in propagation in urban areas.

  • Evaluate the effect of these objects and

compare to the known mechanisms.

Takada Lab - TokyoTech 4

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SLIDE 5

Methodology

  • Performing a number measurements in the

urban areas to clarify previously mentioned facts.

  • Obtaining the angular and temporal profile of

the received power.

  • Distinguishing clusters by examining the

azimuth-delay power profiles.

  • Identifying the probable corresponding scatterer

to each cluster.

Takada Lab - TokyoTech 5

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SLIDE 6

Measurement

  • Small Cell
  • Low Height Antennas
  • Dense Urban Area
  • Line-of-Sight
  • AoA Analysis
  • Delay Analysis

Takada Lab - TokyoTech 6

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SLIDE 7

Measurement Process +

m 60

Tx Rx

  • directivity
  • step rotation
  • 30 sec measurement in each step
  • 10
  • 3
  • constant speed 5 rpm

rotation

  • Takada Lab - TokyoTech

7

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SLIDE 8

System Block Diagram

Cesium Oscillator Controller

Sleeve Antenna

Rx Data Recorder trigger

Tx Rx

3.35 GHz PN-9 50 Mcps 10 W Tx ATT level

Patch Array

Controller Cesium Oscillator Amp Oscilloscope 5 rpm Rotation (free run) step Rotation

  • 3

beamwidth Sidelobe -26dB

  • 10

Both receiver and transmitter antennas are installed on the roof- tops of different car at the same height of 3 meters.

Takada Lab - TokyoTech 8

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SLIDE 9

Considerations

  • Only single-bounce reflections can be

considered in the analysis, but still many scatterers can be identified.

  • The processing is not high resolution due to

using directive antenna. There are space and time resolution limits.

  • Measurements were accomplished during

midnights with little traffic in the streets.

  • Measurements were accomplished in February

with no leaves on the trees.

Takada Lab - TokyoTech 9

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SLIDE 10

Location 1 (2 Points)

24 m

10 m

50 m

13 m

47 m

16 m

39 m

10 m

40 m

4 m

28 m 26 m Honmachidori St. 26 m

Tx Rx

60 m

P1 P2 P1 P2 Kannai Oodori Ave.

N

Yokohama, Kannai, Kannaiodori

Takada Lab - TokyoTech 10

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SLIDE 11

Location 2 (3 Points)

13 m 16 m Bankokubashidori St. (30 m) Kaigandori St.

18 m

N

Tx Rx

60 m

98 m 85 m P1 P2 P1 P3 P3 P2

Yokohama, Kannai, Kaigandori

Takada Lab - TokyoTech 11

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SLIDE 12

Analysis Process (1)

Rx

  • Preparing the precise

map of the measurement area, including every object located there.

  • Some building

irregularities are included, parked cars are not included.

Takada Lab - TokyoTech 12

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SLIDE 13

Analysis Process (2)

Tx Rx

  • Griding the map

according to the time zone ellipses and AoA lines.

  • Only single-bounce

reflected waves can be analyzed.

Takada Lab - TokyoTech 13

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SLIDE 14

Analysis Process (3)

  • Conforming the

azimuth-delay-power spectrum with the grid map of the environment.

  • There is power from

inside building zones because of single- bounce assumption.

Takada Lab - TokyoTech 14

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Analysis (4)

  • The received power has a clustered pattern in

space.

  • The clustered waves scattering sources can be

estimated by this method.

  • Some clusters have been identified without any

visible objects conformed. This can be due to multi-reflection effect.

  • Some objects were identified as scattering

source.

Takada Lab - TokyoTech 15

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Example of Identified Objects (1)

  • Over roof-top

signboard.

Takada Lab - TokyoTech 16 Tx Rx

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SLIDE 17

Example of Identified Objects (2)

  • A traffic sign.

Tx Rx Takada Lab - TokyoTech 17

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SLIDE 18

Identified Objects

Identified Objects Description

  • No. in

Location 1

  • No. in

Location 2 15 8 14 10 2

Cable box

3

Vending machine

2 15 7 10 10 4

Signboard Street light (Lamppost) Traffic sign Traffic light Others

Takada Lab - TokyoTech 18

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SLIDE 19

Received Power Contributions

Scattering from Identified Objects Wall Reflection Multi-reflection Clustered Received Waves Not Clustered Received Waves With No Specular Wall Reflection Presented

(Averaged Over 2 Scenarios)

With Specular Wall Reflection Presented

(Averaged Over 3 Scenarios)

43% 27% 19%

11%

31% 19% 24% 26%

(LoS power is not considered in the analysis)

Takada Lab - TokyoTech 19

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SLIDE 20

Conclusions

Typical metallic objects in the urban areas seem to have a significant effect in the propagation channel. It seems that in some situations, the objects have a stronger impact than the building’s wall surfaces with the same alignments and close distances. At least in some especial scenarios, by-object scattered waves can be dominant phenomenon in the propagation channel.

Takada Lab - TokyoTech 20

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Thank you very much !

Takada Lab - TokyoTech 21

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  • 4
  • 3
  • 2
  • 1

1 2 3

  • 1

8

  • 1

2

  • 6

6 1 2 1 8 角 度 （ ° ）

水 平 面 内

Antenna Gain (dB) Angle of Arrival ( )

  • 180
  • 30

180 30

Receiver Antenna Directivity

Takada Lab - TokyoTech 22

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SLIDE 23

Data Acquisition

D a t a L e n g t h ：511 c h i p s 1 c h i p ： D e l a y P r

  • f

i l e W i n d

  • w

L e n g t h ：10.22 μsec 30.66 msec ： ×3000 D a t a r e c

  • r

d e r s a m p l i n g r a t e ： 48000 s a m p l e /sec

The number of samples in each delay profile：1472 samples

Oscilloscope and data recorder effects Observation Window:

sec n

20

Takada Lab - TokyoTech 23

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SLIDE 24

Azimuth Power Profile L2 P1

  • 80
  • 70
  • 60

Normalized Power (dB)

90 180 270 360

DOA ( )

  • 90

Received Power Received Power Ex LoS Received Power Ex IdOb Received Power Ex W Received Power Ex Cl

Takada Lab - TokyoTech 24

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SLIDE 25

Power Distribution L1

  • 70

Normalized Power (dB)

  • 80
  • 90
  • 100
  • 115
  • 125

L1 P2 L2 P1

Takada Lab - TokyoTech 25

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SLIDE 26

Sample PDP

°

  • 8
  • 7
  • 6
  • 5
  • 4
  • 3
  • 2
  • 1

P

  • w

e r ( d B m ) 30 samples

Takada Lab - TokyoTech 26

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SLIDE 27

Uncorrelated Fading

Takada Lab - TokyoTech 27

wall surface (or any other object) Rx beam ( ) Tx Angular Spread ( ) Tx rotation route with diameter

t

d

t

AS ° 10

Rx beam point Illuminated Area

Χ Χ = sin ρ

r r

d ϕ ϕ λ π ∆ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = Χ sin 2

;

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SLIDE 28

Map including Objects

Rx Takada Lab - TokyoTech 28