1. Noise Figure vs. IP3 Skip Crilly CTO, Cellular Specialties, Inc.

2. Agenda The Near/Far Problem Uplink The Near/Far Problem Downlink
UL Attenuation Requirements at the Head End
CSI Contact Information
Questions

3. The General Near/Far Problem
Co-channel UL interference;
DAS UE to macro
WSP A eNodeB
serving macro
WSP A eNodeB
serving DAS
Band-filtered DAS,
eg RF over fiber.
WSP B eNodeB
Active DAS
FAR
(Near to Far)
To/from other server antennas
FAR
NEAR
Wall and window attenuation
WSP B
Wanted
WSP A UE
Unwanted
WSP B UE

4. The Near/Far Problem Uplink

5. Straight Line Antenna Spacing (m)
Near/Far is affected by Line-of-Sight Path Losses
Straight Line Antenna Spacing (m)
700 MHz LOS Path Loss(dB)
850 MHz LOS Path Loss(dB)
1900 MHz LOS Path Loss(dB)
2100 MHz LOS Path Loss(dB) 1 29 31 38 39 10 49 51 58 59
100 69 71 78 79
1000 89 91 98 99
Unwanted UEs are not carried by the DAS and are not DAS-locally power controlled.
-Indoor UE to server antenna Loss: 29 ~ 59 dB; 1 to 10 meters; GHz
Assuming that the unwanted UE’s Tx power is +23 dBm, then the unwanted (i.e. Near) power at the DAS server antenna is:
-6 dBm to -56 dBm per UE. Ten UEs: UL Power = +4 to -46 dBm.

6. Near/Far: Uplink LTE DAS problems
Co-channel UL interference;
DAS UE to macro eNB not serving
WSP A eNodeB
serving macro
WSP A eNodeB
serving DAS
Band-filtered DAS,
eg analog over fiber.
WSP B eNodeB
Active DAS
SFDR: 51 dB in 10 MHz BW
SFDR = 97 dB*Hz2/3 = 51 dB MHz)
(generally LASER-diode caused)
-86 dBm/10 MHz
4 dB NF
15 dBi antenna gain
14 dB UL SNR
700 MHZ
(Assume ten server antennas = 10 dB loss to/from server)
Signals and Noise at the RU Uplink RFconnector:
Unwanted UL Power : -16 dBm per UE
UL Noise: -67 dBm / 10 MHz (=UL PWR-SFDR10 MHz)
Wanted UE UL: dBm Tx ; -23 dB SNR10 MHz
Wanted UE UL : dBm Tx ; 0 dB SNR10 MHz
89 dB path loss at 1 km Line-of-Sight dB scattering loss
Wall attenuation 20 dB
80 dB path loss; 100 m LOS;
DL +10 Tx server ant.,
-70 Rx UE
29 dB path loss
@1 meter (0 dBi antennas)
WSP B
Unwanted WSP B close-in UE: UL Tx at +23 dBm
Wanted WSP A UE
10 MHz Tx bandwidth
UL Tx : 0 dBm (~power controlled by DL Rx power and/or UL channel quality)

7. Does the Near UE affect the DAS UL Rx noise before the Near UE blocking?
Adjacent Channel Power
-occupies a portion
of the adjacent channel
Adj. Ch. Power EIRP
-34 dBm/10 MHz,
assuming no noise
outside of 9 MHz,
normalized to
+23 dBm EIRP
New Products Coming:
700/800 donor
700/800 CBC (Remember we have a 7/8 CBC now, but it only captures cell and 700, not PCS too. Application SINGLE BAND)
Triplexer: 3 ports 700, 800,
LTE Upper C Uplink with high uplink traffic load
Question: Does the UE Adjacent Channel Power change with Tx power? (next slide)

8. LTE Uplink Signal Characteristics
Adjacent Channel Power
-depends on traffic
-depends on Tx power
-below meas. floor in
this case
New Products Coming:
700/800 donor
700/800 CBC (Remember we have a 7/8 CBC now, but it only captures cell and 700, not PCS too. Application SINGLE BAND)
Triplexer: 3 ports 700, 800,
Adj. Ch. Power EIRP
<-37 dBm/10 MHz,
assuming no noise
outside of 9 MHz,
normalized to
+23 dBm EIRP
(=meas floor)
LTE Upper C Uplink with high uplink traffic load
Question: Does the UE begin to affect the Remote Unit Uplink at a lower power level than the blocking signal affects the UL?(next slide)

9. Near/Far: Uplink LTE DAS problems including UL Adjacent Channel Power
Co-channel UL interference;
DAS UE to macro
WSP A eNodeB
serving macro
WSP A eNodeB
serving DAS
Band-filtered DAS,
eg analog over fiber.
WSP B eNodeB
Active DAS
SFDR: 51 dB in 10 MHz BW
SFDR = 97 dB*Hz2/3 = 51 dB MHz)
(generally LASER caused)
-86 dBm/10 MHz
4 dB NF
15 dBi antenna gain
14 dB UL SNR
700 MHZ
(Assume ten server antennas = - 10 dB loss to/from server to RU)
Signals and Noise at the RU Uplink RF connector:
Unwanted UL Power : -16 dBm per UE
UL RU Noise: -67 dBm / 10 MHz (=UL PWR-SFDR10 MHz)
Wanted UE UL: dBm Tx ; -23 dB SNR10 MHz
Wanted UE UL : dBm Tx ; 0 dB SNR10 MHz
89 dB path loss at 1 km Line-of-Sight dB scattering loss
Wall attenuation 20 dB
29 dB path loss
@1 meter (0 dBi antennas)
80 dB path loss; 100 m LOS;
DL +10 Tx server ant.,
-70 Rx UE
ACP = -73 dBm/10 input; 39 dB total loss)
Prev. slide: Adj. Chan. Pwr : -34 dBm/10 MHz EIRP
WSP B
Unwanted WSP B close-in UE: UL Tx at +23 dBm
Wanted WSP A UE
10 MHz Tx bandwidth
UL Tx : 0 dBm (~power controlled by DL Rx power and/or UL channel quality) 9

10. Uplink: Analysis and Conclusions
UEs that are not “on the DAS”, i.e. not power-controlled by eNodeBs on the DAS, while within the DAS footprint, will affect the uplink performance of a DAS.
The Remote Unit’s RF input attenuation must be increased to “protect” the LASER from the strong unwanted UE UL signal.
This increased input attenuation raises the effective input noise of the DAS UL, or decreases uplink gain, all else being equal.
The resulting increase of the effective UL Rx input noise will cause UEs that are “on the DAS” to experience increased UL Tx power, reduced uplink throughput, dropped connections, and will cause higher co-channel interference to a non-served macro site.
A UE’s typical Adjacent Channel Power (ACP) may generally be below the Rx broadband power of the DAS UL. This UE ACP occurs in the adjacent channels, while blocking occurs in the entire DAS UL band. Further, ACP caused by a UE is intermittent and has partial spectral content. However, blocking in a DAS can occur with partial channel-occupied LTE strong signals applied.

11. The Near/Far Problem Downlink

12. Downlink Issue: Which happens first?
Degradation to “Non-DAS-carrier(s)” due to broadband noise caused by the DAS
Or, “Blocking” of the UE by the carrier(s)’ DL signals being carried on the DAS.
Assumptions (these assumptions result in a worst case for blocking):
Assume that the other WSP carrier(s) are always present at full power on the DAS (not generally the case).
Assume that the other carrier(s)’ signals are close in and concentrated in the next 10 MHz adjacent channel (not generally the case).
A measurement was performed to look for 100% lost desired signal, not degradation at a level of adjacent channel signal power.
At greater offsets, beyond the adjacent channel, the rejection of the receiver is expected to be greater than at the adjacent channel.

13. +20 dBm Downlink Tx Power from WSP A Active DAS
Near/Far LTE Downlink Network De-sense due to OoB noise,
assuming no blocking occurs
WSP B
+20 dBm Downlink Tx Power from WSP A Active DAS
700 MHZ
DAS A -42 dBm/MHz(+20 dBm)
DAS A:-35 dBm/MHz(+20 dBm)
DAS B: -36 dBm/MHz(+20 dBm)
DAS C:-47 dBm/MHz(+20 dBm)
DAS C:-35 dBm/MHz(+20 dBm).
+53 dBm/10 MHz EIRP LTE
+20
server antenna
composite 700 MHz
89 dB path loss at 1 km Line-of-Sight
15 dB (0 dB to 40 dB) wall / prop. attenuation
49 dB path meters (0 dBi)
UE-caused Noise
(Typ. -36 to -76 dBm/10 MHz)
DAS-caused
64 QAM ~ possible
Signal:-51 dBm/10 MHz; Noise:-100 dBm/10 MHz
A: -81 dBm/ 10 MHz
A:-74 dBm/ 10 MHz
B: -75 dBm/ 10 MHz
C:-86 dBm/ 10 MHz
C: -74 dBm/ 10 MHz
Sub
WSP B
-75dBm/10 MHz required for 64 QAM
DAS-caused De-sense: 14 to meters

14. UE Blocking / Adjacent Channel Selectivity Measurement
Simulates the undesired
WSP A DL signal on the DAS
WSP B desired
AWGN Modulated Signal Generator
desired
Test antenna
Spectrum
Analyzer
To measure
power
undesired
~0.3 m
-20 dBm/10 MHz
Measured using test antenna
Sub
WSP B
Desired signal : “one bar” of downlink 700 MHz LTE 4G
Speed test: 1.3 Mbps DL; 400 kbps UL
Speed test result was unchanged while OoB
at device was held at or below -20 dBm/10 MHz.
Undesired signal
AWGN
modulated
Device loses LTE connection,
while interference at device ~ -10 dBm/10 MHz
Desired signal

15. +20 dBm Downlink Tx Power from Active DAS; WSP A
Near/Far LTE Downlink Network De-sense Compared to Blocking/Adj. Ch. Selectivity
+20 dBm Downlink Tx Power from Active DAS; WSP A
WSP B desired
700 MHZ
Assumptions:
-Blocker is continuous high power
-Blocker is concentrated at close-in freq.
-UE device antenna same as test antenna
A: -42 dBm/MHz(+20 dBm)
A:-35 dBm/MHz(+20 dBm)
B: -36 dBm/MHz(+20 dBm)
C:-47 dBm/MHz(+20 dBm)
C:-35 dBm/MHz(+20 dBm)
Blocking Signal from WSP 10 m:
= -29 dBm/10 MHz
UE margin >=9 dB
(i.e. the margin from previous slide)
+53 dBm/10 MHz
EIRP LTE
89 dB path loss at 1 km Line-of-Sight
49 dB path loss
@10 meters (0 dBi)
DAS-caused Noise
at device:
15 dB (0 dB to 40 dB) wall / prop. attenuation
undesired
desired
(Typ. -36 to -76 dBm/10 MHz)
UE-caused Noise
A: -81 dBm/ 10 MHz
A:-74 dBm/ 10 MHz
B: -75 dBm/ 10 MHz
C:-86 dBm/ 10 MHz
C: -74 dBm/ 10 MHz
64 QAM ~possible
UE Signal:-51 dBm/10 MHz; UE Noise:-100 dBm/10 MHz
Sub
WSP B
-75dBm/10 MHz required for 64 QAM
DAS-caused De-sense: 14 to meters 15

16. UE DL Blocking and DL Noise Analysis and Conclusions
At a level of broadband noise from the DAS that de-senses the UE device by 14 to 26 dB, the device has at least 9 dB of “blocking margin”, i.e. the UE device can be 9 dB closer to the server antenna. Note: this was tested on one UE.
As a result of above, an OoB noise reduction of the “best” 14 dB de-sense DAS product of 23 dB (=9+14 dB) is required so that Near-Far DAS system performance can be UE device-limited.
Typical DAS conditions probably result in lower blocking activity than measured in this test.
OoB DAS noise affects all of the band, all of the time; blocking only affects the UE when the DAS DL RF power is present at an offset that can cause blocking, depending on UE IF filters, etc.
Other UE devices may perform differently. However, many UEs are based on a common RF chipset. And, UE devices need to operate well near (~< 3 m distant) +10 dBm EIRP other-WSP femtocells, i.e. not be blocked by the femto.

17. Near/Far Measurements
WSP B
WSP A RF Source
Test antenna
DAS
DL test: Use
Spectrum Analyzer
to measure
Out-of-band
power
1~10 m
Sub
WSP B
Other-WSPs’ UE:
UL test: Run speed test
application to cause UL traffic.
DL test: Run DL speed test to check
for effect of out-of-band power
WSP A UE:
UL test: Run Uplink speed test
-Ensure that UE is on the DAS
-UE located at edge of DAS coverage

18. Near/Far Remedies Improved DAS performance
Lower broadband noise
Stronger UL signal handling
Improved UL AGC characteristics
Lower RF power per server antenna
Use more server antennas per area
Locate server antennas at higher distance from numbers of UEs

19. UL Attenuation Requirements at the Head End
Why is attenuation needed?
How much is needed?
Where should attenuation be placed?

20. Objective: Gain Balance the UL/DL Why
Objective: Gain Balance the UL/DL Why? 3GPP: Power Control & Interference Management
+5 dB NF
+4 dB NF
If : change the power of both tones by 1 dB: then:
DAS
Interface
Unit
BTS/
eNodeB
DAS
Head End
DAS
Remote
If IMD 3rd ,the power of 3rd IMD reduces by 3 dB.
Po=+43 dBm
Premote=+23 dBm
Equivalent Input Noise
=-100 dBm/10 MHz
Overall Loss = 20 dB
UL=DL
fwd-rev link balanced gain
Equivalent Input Noise
=-80 dBm/10 MHz
(Single Remote)
(eNodeB limited)
How do we provide 20 dB of loss in the Uplink? 20

21. LASER requires front-end Gain to meet UL Noise Figure
+5 dB NF
+4 dB NF
If : change the power of both tones by 1 dB: then:
DAS
Interface
Unit
BTS/
eNodeB
DAS
Head End
DAS
Remote
If IMD 3rd ,the power of 3rd IMD reduces by 3 dB.
Po=+43 dBm
Premote=+23 dBm
Overall Loss = 20 dB
UL=DL
fwd-rev link balanced gain/loss
Equivalent Input Noise
=-100 dBm/10 MHz
Equivalent Input Noise
=-80 dBm/10 MHz
(Single Remote)
Check Atten/Gain
here
UL Gain is required here to meet Remote NF Spec
Photodiode
LASER
Typical Gain dB 21

22. DIU Attenuation is required to balance the UL/DL
60 dB UL Attenuation is
required (40 dB +20 dB)
+5 dB NF
+4 dB NF
If : change the power of both tones by 1 dB: then:
DAS
Interface
Unit
BTS/
eNodeB
DAS
Head End
DAS
Remote
If IMD 3rd ,the power of 3rd IMD reduces by 3 dB.
Po=+43 dBm
Premote=+23 dBm
Overall Loss = 20 dB
UL=DL
fwd-rev link balanced gain/loss
Equivalent Input Noise
=-100 dBm/10 MHz
Equivalent Input Noise
=-80 dBm/10 MHz
(Single Remote)
Typical Loss 3 dB
Gain is required here to meet UL NF Spec
Atten/Gain
here
LASER
Photodiode
Typical Gain dB 22

23. Proposed Solution: Reduce post-DAS attenuation, reduce DAS UL gain
e.g. 40 dB UL Atten.
e.g. 20 dB UL Gain
In front of LASER.
If : change the power of both tones by 1 dB: then:
DAS
Interface
Unit
BTS/
eNodeB
DAS
Head End
DAS
Remote
If IMD 3rd ,the power of 3rd IMD reduces by 3 dB.
Po=+43 dBm
Premote=+23 dBm
Overall Loss = 20 dB
UL=DL
fwd-rev link balanced gain/loss
(Single Remote)
REDUCE THIS GAIN
To ~20 dB
Tradeoff strong signal and NF
Typical Loss 3 dB
Adjust Atten/Gain
LASER
Photodiode
Typical Gain dB: change to 20 dB 23

24. Questions? Skip Crilly CTO, Cellular Specialties, Inc.
Phone: (509)

25. Thank You! Thank you for your continued support of
Cellular Specialties’ Products!