BIRST An Indoor Radio Simulation Environment

1
BIRST An Indoor Radio Simulation Environment

• Haiyun Tang and Kam Lau

2
Background

• Existing radio simulation tools
• Lucents WISE (Wireless System Engineering)
• Image-based 2-D/3-D ray tracing
• Source ? Images ? Images of image
• Rappaport at Virginia Tech
• SIRCIM/SMRCIM
• Impulse data generator based on statistical
  modeling (floorplan independent)
• BIRST (Berkeley Indoor Radio Simulation Tool)
• 2D radio propagation simulator based on space
  partitioning

3
Image-based ray tracing

• Exponential complexity growth with number of
  reflections stages
• Need to repeat simulation for a different
  receiving location
• Complexity

Tx
4
Space partitioning

• Partitioning until
• Homogeneous
• Maximum power below cutoff
• Partition database
• One for each floorplan
• Contains all the partitions generated
• Partition record
• Source
• Attenuation
• Coverage area

5
Fundamental difference between ray tracing and
space partitioning
Ray tracing
4th stage
3rd stage
2nd stage
1st stage
Original
6
BIRST advantages

• WISE complexity
• BIRST advantages
• Speed
• Accuracy
• No need to repeat simulation for different
  receiving locations

7
BIRST simulation process
Wall 0 0 55 0 0.8 0.6 Wall 55 0 55 36 0.8
0.6 Wall 0 36 55 36 0.8 0.6 Wall 0 36 0 0 0.8
0.6 Wall 5 6 5 0 0.8 0.6 Antenna 26 18 Antenna 11
27

• Partition 1
• Source (26,18)
• Attenuation 1.0
• Coverage(30,15), (30,19), (40,10), (40,24)
• Partition 2

Floorplan
Partition Database
Impulse, radio map, etc.
8
A view of BIRST GUI
9
Channel impulse and frequency response
Impulse response from (26, 18) to (49, 9) on Soda
3rd floor
(26,18) ? (49,9)
Multipath component amplitude
250ns
Multipath propagation distance
Channel frequency response from (26, 18) to (49,
9)
Channel frequency response from (26, 18) to (49,
9)
-15
-21
-20
-22
-25
-23
-30
-24
(dB)
(dB)
2
-35
2
H(f)
H(f)
-25
-40
-26
-45
20MHz at 5.25GHz
200MHz at 5.25GHz
-27
-50
-28
-55
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
Hz
7
Hz
x 10
8
x 10
10
Signal power map
Transmitter (6,19)
800MHz narrowband
Cory 5th floor radio power distribution
0.14
0.12
0.1
0.08
PDF
0.06
Dynamic range for 99.9 coverage 75dB
0.04
0.02
0
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
dB
11
Angle of arrival
(26,18) ? (16,16)
Transmitter
Receiver array
a
Ds
12
Narrowband multiple-antenna channel
Tx1
Rx1
Tx2
Rx2
Tx3
Rx3
Tx4
Rx4
Tx5
Rx5
Tx1
Tx2
Tx3
Tx4
Tx5
H
Multipaths for hii
Rx1
h11
h12
h13
h14
h15
Rx2
h21
h22
h23
h24
h25
Alej2pdl/l
A
Rx3
h31
h32
h33
h34
h35
Rx4
h41
h42
h43
h44
h45
Rx5
h51
h52
h53
h53
h55
d
13
Narrowband multiple-antenna capacity map
Capacity distribution on Soda 3rd floor
400
350
Mean 12.8 STD 4.9
300
250
PDF
200
150
100
50
0
0
5
10
15
20
25
30
35
40
45
Capacity bits/sec/Hz
Antenna array size 5 Position (26, 18) S/N
45dB Carrier frequency 5GHz (l 0.06m) Antenna
separation 0.12m (2l)
14
Capacity increase with antenna array size
Calculated mean capacity over Soda 3rd floor for
different number of antennas
25
Mean
STD
20
15
Capacity
10
Antenna array size 1,3,5,7,9 Position (26,
18) S/N 45dB Carrier frequency 5GHz (l
0.06m) Antenna separation 0.12m (2l)
5
0
1
2
3
4
5
6
7
8
9
Antenna array size
15
Antenna array and distributed antennas
of antennas 5 S/N 45dB Frequency 5GHz l
0.06m Array spacing 2l
16
Antenna array and distributed antennas (contd)
Capacity distribution comparison between antenna
array and distributed antennas
0.08
Array
Distributed
0.07
Mean 11.9 STD 2.6
0.06
0.05
PDF
0.04
0.03
Mean 12.8 STD 4.9
0.02
0.01
0
0
5
10
15
20
25
30
35
40
45
Capacity bits/sec/Hz
of antennas 5, S/N 45dB, Frequency 5GHz, l
0.06m, Array spacing 2l
17
Plans

• Integrate BIRST simulation core with Simulink
• Add diffraction model
• 3-D space partitioning

18
Multiple-antenna frequency-selective fading
channel capacity

• Capacity with fixed input
• Optimal solution (2-D water filling)
• Channel capacity

i
f
19
Optimal capacity simulation and comparison
(26,18) ? (40, 30.375)
Capacity comparison optimal and sub-optimal system
14
Optimal (water-filling, feedback)

Sub-optimal (no water-filling, receiver-side
processing
12
only)

10
8
Capacity bits/sec/Hz
6
4
2
0
10
15
20
25
30
35
40
45
50
lii(f)
Signal-to-noise ratio (dB)
5 antennas, 64 sub-carriers over 20MHz band at
5.2GHz, antenna sep. 0.12m