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

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

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

The Near/Far Problem Uplink

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; 0.7-2.1 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.

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 (@10 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: -90 dBm@ 0 dBm Tx ; -23 dB SNR10 MHz Wanted UE UL : -67 dBm@ +23 dBm Tx ; 0 dB SNR10 MHz 89 dB path loss at 1 km Line-of-Sight + 15 dB scattering loss Wall attenuation 20 dB 80 dB path loss; 100 m LOS; DL +10 Tx DL @ server ant., -70 dBm @ Rx DL @ UE 29 dB path loss @1 meter (0 dBi antennas) WSP B Unwanted WSP B close-in UE: UL Tx at +23 dBm (@max) Wanted WSP A UE 10 MHz Tx bandwidth UL Tx : 0 dBm (~power controlled by DL Rx power and/or UL channel quality)

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 700 + 80 0 SINGLE BAND) Triplexer: 3 ports 700, 800, 1900-2.1 LTE Upper C Uplink with high uplink traffic load Question: Does the UE Adjacent Channel Power change with Tx power? (next slide)

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 700 + 80 0 SINGLE BAND) Triplexer: 3 ports 700, 800, 1900-2.1 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)

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 (@10 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: -90 dBm@ 0 dBm Tx ; -23 dB SNR10 MHz Wanted UE UL : -67 dBm@ +23 dBm Tx ; 0 dB SNR10 MHz 89 dB path loss at 1 km Line-of-Sight + 15 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 DL @ server ant., -70 dBm @ Rx DL @ UE ACP = -73 dBm/10 MHz @RU 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 (@max) Wanted WSP A UE 10 MHz Tx bandwidth UL Tx : 0 dBm (~power controlled by DL Rx power and/or UL channel quality) 9

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.

The Near/Far Problem Downlink

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.

+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 dBm @ 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 loss@10 meters (0 dBi) UE-caused Noise (Typ. -36 to -76 dBm/10 MHz) DAS-caused Noise @UE 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 26 dB @ 10 meters

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

+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 A @ 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 26 dB @ 10 meters 15

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.

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

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

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

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

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 30-40 dB 21

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 30-40 dB 22

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 30-40 dB: change to 20 dB 23

Questions? Skip Crilly CTO, Cellular Specialties, Inc. Email: scrilly@cellularspecialties.com Phone: (509) 879 0094

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