1. Evaluating Active Components Presenter: Blaine Davidge Westell Technologies 4/8/161Copyright © 2016 | CIBET | All rights reserved

2. A network of spatially separated antenna nodes connected to a common source via a transport medium that provides wireless service within a geographic area or structure What is a Distributed Antenna System (DAS)? Donor Server Remote Amplifier Optical Conversion Head End Signal Source Coax Fiber 4/8/162 Copyright © 2016 | CIBET | All rights reserved

3. What is a Distributed Antenna System (DAS)? ActivePassive A DAS is composed of both active and passive components 4/8/163 Copyright © 2016 | CIBET | All rights reserved

4. Bidirectional Amplifier Setup 4/8/164 Copyright © 2016 | CIBET | All rights reserved

5. RF Sources Feed Fiber DAS Setup Signal Source can be both BDA, BTS and Small Cell. 4/8/165 Copyright © 2016 | CIBET | All rights reserved RF Jumpers from signal source to Fiber DAS headend Optical Fiber cable from Headend to Remotes Coax cable from remotes to Passive components

6. Fiber DAS Remote Unit Head End 4/8/166 Copyright © 2016 | CIBET | All rights reserved

7. Low Freq. & High Freq. Amplifiers – Amplifiers are Characterized by the frequencies they serve. – Power levels that they offer. – Noise Interference and Distortion Problem Introductions – Frequencies in amplifiers are grouped together as an efficient method to better control filtration and gain. – E.g. 700 & Cell or PCS & AWS 4/8/167 Copyright © 2016 | CIBET | All rights reserved

8. Active Component Characteristics 4/8/168 Copyright © 2016 | CIBET | All rights reserved

9. Topics: 7.Spurious Emissions 8.Optical Budget 9.Intermodulation 10.System Degradation 11.Stability Margin 12.Isolation 1.Gain/Attenuation 2.Output Power 3.Noise Figure 4.Noise Power 5.AGC & ALC 6.EVM Distortion 4/8/169 Copyright © 2016 | CIBET | All rights reserved

10. Gain – Amplification of the input signal Determining Factors – Equipment specs – User setting Gain can be limited by the Isolation If input signal is very strong, less gain is required 4/8/1610 Copyright © 2016 | CIBET | All rights reserved

11. Gain Measuring Gain – Signal generator produces CW signal into input port – Set equipment to specified gain – Measure output with spectrum analyzer INSERT DIAGRAM HERE 85dB Gain -60dBm Input 25dBm Output 4/8/1611 Copyright © 2016 | CIBET | All rights reserved

12. Output Power Output Power (Max) – Maximum composite power, typically measured in dBm or watts, that the equipment is capable of producing at the output port Determining Factors – Equipment specs – Maximum Gain – Coverage area – Incoming signal 4/8/1612 Copyright © 2016 | CIBET | All rights reserved

13. Output Power The equipment manufacturer provides a vast portfolio of repeaters and Fiber DAS with output powers ranging from 24dBm to 46dBm – Small Area = BDA provides better Cost/sq.ft. ratio – Large Area= Fiber DAS provides coverage to match Operator requirements. 4/8/1613 Copyright © 2016 | CIBET | All rights reserved

14. Output Power Verifying maximum output power – Signal Generator produces input signal – Gain is set to a level to achieve maximum power output – Spectrum analyzer measures power at output port 85dB Gain -55dBm Input 27dBm Output 4/8/1614 Copyright © 2016 | CIBET | All rights reserved

15. UL Signal Noise Figure (NF) Noise figure is the amount of noise a component adds to the signal without considering the gain. NF = Measured Noise Power - System Gain - White Noise Measuring Noise Figure – Using a signal generator and spectrum analyzer, measure the total UL gain of the DAS – Remove the CW signal and measure the amplified UL noise coming from the DAS – White noise is a constant at -114dBm/MHz 4/8/1615 Copyright © 2016 | CIBET | All rights reserved

16. Noise Floor and SNR Measuring Noise Floor UplinkDownlink Desired Signal Noise Floor 4/8/1616 Copyright © 2016 | CIBET | All rights reserved

17. Noise Floor and SNR Noise Floor – Ambient noise measured when no other signals are present Signal-to-noise Ratio (SNR) – Ratio of usable signal to the noise floor level Noise Figure – Ratio of SNR in /SNR out which is a measure of the additional noise the device is adding to the original input signal. 4/8/1617 Copyright © 2016 | CIBET | All rights reserved

18. Noise Power – When input signals do not occupy the entire band of output signal potential, as in the case of a broadband DAS with a single participant, the output power profile will show signals in the part of the spectrum where input signals are asserted, and noise in the part of the spectrum without input. Output noise power = Input-Noise power + Noise Figure + System Gain. 4/8/1618 Copyright © 2016 | CIBET | All rights reserved

19. AGC and ALC Automatic Gain Control – Continuously adjust the gain to output a desired output power Since Macro network signals fluctuate with changes in traffic volume, so will the input, and thus output signals. The AGC can improve service, but only for voice services. The continuous adjustment of the output power with data services can cause an undesired growing and shrinking of the coverage area. 4/8/1619 Copyright © 2016 | CIBET | All rights reserved

20. AGC and ALC Automatic Level Control – Regulates gain to produce specified output level only at times of maximum traffic on the network If a Macro signal drops (during low traffic hours) the coverage area will still be the same The ALC will adjust the gain to compensate in these circumstances, without any adverse effects to data services 4/8/1620 Copyright © 2016 | CIBET | All rights reserved

21. Error Vector Magnitude (EVM) EVM – Error Vector Magnitude or EVM (sometimes also called receive constellation error or RCE) is a measure used to quantify the performance of a digital radio transmitter or receiver – An 8 point constellation provides 3 bits of data – A 16 point constellation provides 4 bits of data – A 64 point constellation provides 6 bits of data OFDM Signal distortion within an amplifier often shows up as EVM degradation 4/8/1621 Copyright © 2016 | CIBET | All rights reserved

22. Error Vector Magnitude (EVM) Measuring EVM Free of NoiseNoise Interference 4/8/1622 Copyright © 2016 | CIBET | All rights reserved

23. Spurious Emissions – RF Leakage is the production of RF signals by a radio transmitter outside the desired range of operation and potentially causing Interference. – Any signal not deliberately created or emitted RF leakage is caused by in-adequate filtering at the inbound/outbound connections. Shielding and RF screens must be maintained to reduce the effect of RF Leakage Spurious emissions may be caused by faulty equipment, or other equipment nearby that is producing an unwanted signal within the same frequency range 4/8/1623 Copyright © 2016 | CIBET | All rights reserved

24. Spurious Emissions How to test for spurious emissions Uplink Downlink Desired Signal Desired Band Spurious Emissions 4/8/1624 Copyright © 2016 | CIBET | All rights reserved

25. Intermodulation – Creation of un-desired signals by combining two or more signals with different frequencies in a system with nonlinearities Intermodulation causes signal interference 4/8/1625 Copyright © 2016 | CIBET | All rights reserved

26. Intermodulation f 1 f 2 f 1 +f 2 f 2 -f 1 2f 1 -f 2 2f 1 2 2 -f 1 3f 2 -2f 1 4f 2 -3f 1 3f 1 -2f 2 4f 1 -3f 2 IM Tx frequencies Multiple frequencies + High power + Non-linear characteristics = IM 4/8/1626 Copyright © 2016 | CIBET | All rights reserved

27. PIM in Passive Components Intermodulation can be caused by – Contaminated surfaces or contacts – Loose RF connections – Metal flakes or shavings inside RF connections – Inconsistent metal-to-metal contact 4/8/1627 Copyright © 2016 | CIBET | All rights reserved

28. Resiliency to ACI 4/8/16 Copyright © 2016 | CIBET | All rights reserved 28 To measure a system’s resiliency to adjacent channel (next door neighbor spectrally speaking) interference consider two metrics. IIP3 and SFDR

29. Measuring IP3

30. Intermodulation The IIP3 point is not a real operating point because it represents a condition where the intermods have grown to be as strong as the primary signal. The Spurious Free Dynamic Range is the amount of power the amplifier can accept as input above its sensitivity without generating intermods. (IIP3 – RxNoise Floor) * 2/3 = Spurious Free Dynamic Range Noise in BW + Noise Figure SFDR Spurious Free Dynamic Range

31. Degradation and Failure of Active Components – Active components Degrade and fail due to Power and environmental conditions. Active components in DAS are amplifiers and filters and power supplies Amps and filters are different combinations of transistors and capacitors. MTBF= Mean Time Between Failures (80,000hrs or 10 years) 4/8/1631 Copyright © 2016 | CIBET | All rights reserved

32. IMPORTANT CONCEPTS ABOUT OVER THE AIR REPEATERS 4/8/1632 Copyright © 2016 | CIBET | All rights reserved

33. Stability Margin Oscillation – A feedback loop causing signals from the serving antenna to be picked up by the donor antenna, which are then re-amplified in the system In order to avoid oscillation, the total system gain must be lower than the isolation value by a certain amount, call a stability margin. 4/8/1633 Copyright © 2016 | CIBET | All rights reserved

34. Isolation Value – Path loss between server antenna and donor antenna Measuring the isolation value – Signal generator injects CW signal into serving antenna – Spectrum analyzer measures signal coming from the donor antenna – CW Input – Signal Donor = Isolation Value 4/8/1634 Copyright © 2016 | CIBET | All rights reserved

35. Isolation Value Isolation Value – Stability Margin = Maximum Gain Radiated CW Input – Signal Donor = Isolation Value Measuring Isolation Value 4/8/1635 Copyright © 2016 | CIBET | All rights reserved

36. THANK YOU 4/8/1636 Copyright © 2016 | CIBET | All rights reserved