CC11xx range extension and
practical range estimation
Tor-Inge Kvaksrud
Abstract
• This presentation address different methods of
extending range for LPRF equipment. Advantages
and disadvantages is discussed to make the
attendee capable of evaluating and selecting the
proper solution to the final application.
• The second portion address practical range
estimation. A model for open field range
calculation is presented. Finally range in different
common environments are discussed.
Main Topics
• Range extension
–
–
–
–
Matching
LNA
PA
Antenna
• Practical range estimates
– Open field environment
– Indoor environments
Range extension
Transmission budget
•Friis equation
GT GR 2
PR  PT
4 2 d n
PR:
PT:
GR:
GT:
λ:
d:
C:
n2
Power available from receiving antenna.
Power supplied to the transmitting antenna.
Gain in receiving antenna
Gain in transmitting antenna
Wavelength λ=c/f, c=speed of light, f=frequency.
Distance [m]
Speed of light in complete vacuum 2.99792458*10^8 [m/s]
•Sensitivity
The minimum signal power required by receiver to successfully
demodulate the received information with less than 1%
packet error rate (PER). Normally specified with only thermal noise
present.
Transmission budget
-10
-20
received power [dBm]
-30
-40
-50
-60
-70
-80
-90
-100
0
200
400
600
800 1000 1200
distance [m]
1400
1600
1800
2000
Range extension PA
Transceiver
CC1100
switch
Match/filter
PA
Filter
Single-ended 50 Ω interface
• 50 Ω reference impedance
• extended range
• The added complexity
Range extension LNA
LNA
Transceiver
CC1100
Match/filter
switch
switch
Single-ended 50 Ω interface
Example
FTotal
FCC 11XX
 FLNA 
GLNA
CC11xx approximate
External LNA GAIN
LNA
NF =11dB
G=16dB
NF=2.7dB
 Total NF=3.3dB
 Sensitivity improvement (11-3.3)dB=7.67dB
 this more than doubles original range.
Range extension PA & LNA
LNA
Transceiver
CC1100
Match/filter
switch
switch
PA
Filter
Single-ended 50 Ω interface
Example
Transmit power
External LNA GAIN
LNA NF
CC1101 sensitivity 1.2kbps
CC1101 sensitivity improved by LNA
Total transmission budget
Friis’free space atten. over 1400km is about
36dBm
16dB
2.7dB
-111dBm
-118dBm
154dBm
154dB
(Note this is purely a theoretical mathematical example and has no relevance for practical CC1101 applications)
Range extension Antenna
Range extension adoption to requirements
FCC - SRD Regulations
902 - 928 MHz band
FCC 15.249, Single channel
FCC 15.247, Spread Spectrum
FHSS - Frequency Hopping Spread Spectrum
Digital Modulation (e.g. DSSS - Direct Sequence Spread Spectrum)
Output power [dBm]
+30.0
+24.0
+ 6 dBi Antenna gain
FHSS 50 Channels or DSSS
+ 6 dBi Antenna gain
FHSS 25 Channels
FCC 15.247
FCC 15.249
-1.23
Frequency [MHz]
902
928
Practical range estimates
Practical range estimates
• Practical range estimates
– Open field environment
• Outdoor environments suitable for practical comparison
measurements.
– Indoor environments
• Typical operational environments for the final product
Indoor/outdoor, home, factory, vehicle …….
Practical range estimates open field
Transmit antenna GT
Direct transmission
Receive antenna GR
H1
H2
Reflected transmission
Θi
Θr
εr
d
Reflection law  Θi=Θr
Practical range estimates open field
freeeqation
space eqation
Friis freeFriis
space
and gnd model
-10
0
-20
-20
-30
P [dBm]
P [dBm]
-40
-40
-50
-60
-60
-80
-70
Free space
-100
-80
Ground model
-90
-120
0
50
100
150
200
250
300
350
400
450
500
frequency=868MHz
Distance
[m]
frequency=868MHz
H1=H2=0.3m polarisation=Horisontal Er=18
Distance
[m]
Practical range estimates open field
Ground model Horisontal polarization
-20
-30
Friis
H-Polarization
Sens. level(CC2500@500kbps)
Power [dBm]
-40
-50
-60
-70
-80
-90
0
50
H1=H2=1.5m, er=18, freq=2445MHz
100
150
[m]
Practical range estimates open field
Practical range estimates Indoor
PR  PT
GT GR 2
4 2 d n
Environment
•
free space
•
Retail store
•
Grocery store
•
Office, hard partitions
•
Office, soft partitions
•
Metalworking factory, line of sight
•
Metalworking factory, obstructed line of sight
Data copied from the SWRA046A Application report
By Matthew Loy and Iboun Sylla
http://focus.ti.com/lit/an/swra046a/swra046a.pdf
n2
n
2.0
2.2
1.8
3.0
2.6
1.6
3.3
std. deviation
8.7
5.7
7.0
14.1
5,8
6.8
Practical range estimates example
Friis free space eqation and worst case office with hard partitions
-20
-40
-60
Free space
P [dBm]
-80
-100
-120
-140
-160
-180
-200
Worst case Office with hard partitions
20
40
frequency=868MHz
60
80
100
120
140
Distance [m]