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Passive Intermodulation (PIM) testing
Jan-20 Company Confidential
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What is Passive Intermodulation (PIM)
TX signals at site Passive Intermodulation (PIM) Passive Intermodulation (PIM) F1 F2 IM 3 IM 3 IM 5 IM 5 IM 7 IM 7 IM 9 IM 9 PIM = interference PIM = new frequencies generated by Tx signals at a cell site when they encounter “non-linear” junctions in the RF path PIM falling in an operator’s uplink can elevate the noise floor: ▪ Dropped calls ▪ Access failures ▪ Slower data rates Jan-20 Company Confidential
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What is a non-linear junction?
Linear junctions Current Voltage Current increases linearly with applied voltage. High pressure, metal-to-metal contacts Welded or soldered connections. Current Voltage Non-Linear junctions Current does not increase linearly with voltage. Low pressure, metal-to-metal contacts Oxide layers on metal surfaces Arcing across small air gaps or cracks Jan-20 Company Confidential
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What is non-linear at a cell site?
Loose metal-to-metal contacts Poorly terminated RF connectors Metal flakes inside connectors Loose RF connectors Metal flashing on rooftops Loose rivets, screws, etc. Rusty / corroded surfaces Non-linear materials Nickel / Steel Ferrite Jan-20 Company Confidential
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What does PIM look like at the site?
Broad band interference Narrow band spikes Jan-20 Company Confidential
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What does PIM look like to the operator?
PIM Repair High average noise level BUSY QUIET BUSY QUIET Lower average noise level Jan-20 Company Confidential
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Where does PIM occur? F1 F2 IM 3 IM 5 IM 7 IM 9 2*F2–1*F1 3*F2–2*F1 4*F2–3*F1 5*F2–4*F1 2*F1–1*F2 3*F1–2*F2 4*F1–3*F2 5*F1–4*F2 PIM occurs at mathematical combinations of the Tx frequencies F1 = 1930 MHz ∆ = 15 MHz F2 = 1945 MHz IM3 = (2*1930) – (1*1945) = MHz IM3 = (2*1945) – (1*1930) = MHz IM5 = (3*1930) – (2*1945) = MHz IM5 = (3*1945) – (2*1930) = MHz IM7 = (4*1930) – (3*1945) = MHz IM7 = (4*1945) – (3*1930) = MHz IM9 = (5*1930) – (4*1945) = MHz IM9 = (5*1945) – (4*1930) = MHz ∆ = 15 MHz Jan-20 Company Confidential
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Where does PIM occur? (the easy way)
F1 F2 IM 3 IM 5 IM 7 IM 9 20 MHz F1 = 940 MHz F2 = 960 MHz ∆ = 20 MHz IM3 = 1930 – 15 = 920 MHz IM3 = = MHz IM5 = 1915 – 15 = 900 MHz IM5 = = MHz IM7 = 1900 – 15 = 880 MHz IM7 = = MHz IM9 = 1875 – 15 = 860 MHz IM9 = = MHz Jan-20 Company Confidential
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What is the bandwidth of PIM signals?
200 KHz 600 KHz 1 MHz 1.4 MHz 1.8 MHz PIM bandwidth increases as carrier bandwidth increases PIM bandwidth increase with PIM order F1 = 200 KHz F2 = 200 KHz IM3 bandwidth = 3* 200 KHz = 600 KHz IM5 bandwidth = 5* 200 KHz = 1000 KHz = 1 MHz IM3 bandwidth = 7 * 200 KHz = 1400 KHz = 1.4 MHz IM3 bandwidth = 9 * 200 KHz = 1800 KHz = 1.8 MHz Jan-20 Company Confidential
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Can one wide band carrier generate PIM?
5 MHz 5 MHz 5 MHz 5 MHz 5 MHz 5 MHz 5 MHz 5 MHz 5 MHz IM 3 IM 5 IM 7 IM 9 YES ! Signal is composed of individual sub-carrier frequencies Carrier bandwidth = 5 MHz IM3 bandwidth = 3* 5 MHz = 15 MHz IM5 bandwidth = 5* 5 MHz = 25 MHz IM7 bandwidth = 7 * 5 MHz = 35 MHz IM9 bandwidth = 9 * 5 MHz = 45 MHz Jan-20 Company Confidential
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Reduced Tx Range - No impact on customers
Band Tx range Rx range Possible IM3 range MW82119A range Full coverage? 700U/L MHz MHz 776 – 787 MHz 698 – 716 MHz Not possible MHz MHz MHz YES 850 869 – 894 MHz 824 – 849 MHz 844 – 849 MHz 900 925 – 960 MHz 880 – 915 MHz 890 – 915 MHz 1800 1805 – 1880 MHz 1710 – 1785 MHz 1730 – 1785 MHz 1900 1930 – 1990 MHz 1850 – 1910 MHz 1870 – 1910 MHz PCS/AWS 2110 – 2155 MHz 1710 – 1755 MHz Jan-20 Company Confidential
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Why are we just now seeing this problem?
Before: Simple antennas Single bands per feeder Narrow carrier bandwidths Tx and Rx on separate feeders >50 dB Tx/Rx isolation! -50 dB -50 dB PIM Rx Tx Rx Jan-20 Company Confidential
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Why are we just now seeing this problem?
Today: Complex antennas More RF connections Multiple bands per feeder Wider bandwidth carriers Tx and Rx combined on each feeder ▪ More potential PIM sources ▪ Increased probability of low order products ▪ No Tx/Rx isolation PIM Tx/Rx 850/1900 Tx/Rx 850/1900 Jan-20 Company Confidential
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What is the solution? Eliminate non-linearity so that multiple frequencies can peacefully co-exist! Choose site locations wisely Choose RF components wisely Install carefully Verify linearity using a PIM test LTE GSM UMTS CDMA Jan-20 Company Confidential
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Can I see PIM with my Site Master?
Load NO! Sweep tests measure reflected energy caused by changes in impedance Single frequency transmitted Low power (1 to 10mW ) Measures same frequency Displays ratio of PR / PT Change frequency & repeat Impedance mismatches may not cause PIM DUT PT PR Dent Jan-20 Company Confidential
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How does PIM test equipment work?
Tx combiner Must be low PIM ! F1 Duplexer DUT TX F2 PIM Load IM RX Receiver Transmits two test frequencies High power (2x 20W typical) Measures signal level at the IM frequency Jan-20 Company Confidential
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dBc dBm dBm vs. dBc Two different ways to describe the same PIM signal
Carrier Power dBc dBm 0 dBc Two different ways to describe the same PIM signal dBm uses 0 dBm as reference dBc uses carrier power as reference Jan-20 Company Confidential
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Why do we measure IM3 ? F1 F2 IM 3 IM 3 A A Noise Floor IM 11 IM 9 IM 7 IM 5 IM 5 IM 7 BTS Uplink (Rx) BTS Downlink (Tx) IM3 is the highest magnitude / most accurate to measure IM3 “characterizes” the linearity of the system Reducing IM3 reduces all PIM products Jan-20 Company Confidential
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What test frequencies should I use?
F1 & F2 should be in the Downlink band F1 & F2 must be spaced far apart to put IM3 in Uplink band F1 & F2 will be outside an operator’s licensed spectrum! Use Guard band frequencies for fixed tone tests (to reduce chance of interference) Anritsu sweep test (Swept PIM & DTP) are so fast, they will not cause interference F1, F2 & IM3 must all be able to pass through the system Jan-20 Company Confidential
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What might block PIM test frequencies?
850 1900 Antennas MHz MHz Tower Mounted Amplifiers (TMA) Filters Lightning surge protectors Sweep test to verify Use correct PIM test set By-pass frequency limiting devices Jan-20 Company Confidential
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Proceso de prueba sugerido.
START Site Master Sweep test DTF Repair PIM Master Noise Floor Static PIM vs. TIME Dynamic PIM vs. TIME Save Results END Repair DTP Repair Jan-20 Company Confidential
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What is Distance-to-PIM™ (DTP) ?
Distance-to-Fault (DTF) Similar to DTF introduced in the Site Master in 1997 DTP invented by Anritsu and first introduced in 2010 Shows the location of PIM faults Inside the feed system Beyond the antenna DTP is a static test! Does not eliminate the need for dynamic PIM testing. Distance-to-Fault (DTF) Jan-20 Company Confidential
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What is DTP Resolution? MW82119A: Frequency Option Resolution 700 MHz (U) 7.1 m / 23.4 ft 700 MHz (L) 5.5 m / 18.0 ft 850 MHz 900 MHz 6.3 m / 20.6 ft 1800 MHz 2.4 m / 7.9 ft 1900 MHz 3.3 m / 10.8 ft 1900/2100 MHz 2.9 m / 9.6 ft PIM sources – 6m separation Resolution = ability to resolve closely spaced PIM sources Resolution = (150 * VF) / BW PIM sources – 3m separation Jan-20 Company Confidential
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What DTP accuracy can be achieved?
VF = .80 ± 0.5m possible Many variables impact accuracy Propagation velocity Signal magnitude Resolution confusion Electrically long devices (TMA, filters) Big PIM sources masking smaller PIM sources ∆ 10.9 FT VF = .88 Jan-20 Company Confidential
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Anritsu PIM test solutions
Jan-20 Company Confidential
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First Generation PIM Master
Introduced PIM Master™ Dec. 2010 Distance-to-PIM™ technology 43 to 46 dBm output power (20 to 40 W) Controlled using: BTS Master Cell Master Site Master Spectrum Master Discontinued: Last order June 30th, 2013 Three models: 850 MHz, 900 MHz, 1900/2100 MHz Jan-20 Company Confidential
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New Second Generation PIM Master
World’s first: battery operated high power PIM analyzer Lightweight / small size one-half the weight one-forth the size 25 to 46 dBm (0.3 to 40 W) Distance-to-PIM™ No external controller required Six models: 700 MHz (U/L), 850 MHz, 900 MHz 1800 MHz, 1900 MHz, 1900/2100 MHz Jan-20 Company Confidential
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MW82119A – PIM testing at top of the tower
Remote Radio Head (RRH) sites Fiber & DC power to RF unit RF path is jumper cable + antenna PIM sources reduced, but not eliminated Traditional test equipment not useful: Heavy No AC power MW82119A is the solution: Light weight Battery operation Remote control option Jan-20 Company Confidential
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MW82119A – Higher capacity DAS installations
Distributed Antenna Systems (DAS): Many PIM sources Metal near antennas Many RF connections Operators co-located on DAS More frequencies mixing together Increased probability of IM in RX band MW82119A is the solution: Battery operation for remote testing Low power capability Distance-to-PIM technology Jan-20 Company Confidential
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MW82119A – Simplifies site testing
Rooftop sites: Access challenges: Ladders No elevator Many external PIM sources: Metal on building Rusty equipment MW82119A is the solution: Light weight / small size Distance-to-PIM technology Jan-20 Company Confidential
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MW82119A - Key features Parameter Specification Small size
350 x 314 x 152mm (13.8 x 12.4 x 6.0in) Light weight 9 kg to 12 kg * (20 lb to 27 lb) Battery operation > 3.0 hours Wide power range 25dBm to 46dBm (0.3W to 39.8W) Distance-to-PIM™ YES PIM vs. Time Swept PIM Noise floor Remote Control GPS option Power Meter option Full-featured PIM test set! * - Weight varies by frequency option (see next slide) Jan-20 Company Confidential
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MW82119A – Available models 6 frequency options available now
Model Number F1 F2 IM 700 MHz (L/U) MW82119A-0700 734 – MHz 745 – 766 MHz 698 – 716 MHz / 779.5 – 804 MHz 850 MHz MW82119A-0850 869 – MHz 881.5 – 894 MHz 824 – 849 MHz 900 MHz MW82119A-0900 925 – MHz 951.5 – 960 MHz 880 – 915 MHz 1800 MHz MW82119A-0180 1805 – MHz – 1880 MHz 1710 – 1785 MHz 1900 MHz MW82119A-0190 1930 – MHz 1950 – 1990 MHz 1870 – 1910 MHz 1900/2100 MHz MW82119A-0192 1930 – 1935 MHz 2110 – 2155 MHz 1710 – 1755 MHz 6 frequency options available now 3 more in development – LTE800, UMTS2100, LTE (Estimated: September 2013) Jan-20 Company Confidential
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MW82119A – Hybrid vs. Filter combiner
Hybrid combiner: F1 & F2 can be any frequency ½ power produced goes into load Fans required to remove heat dissipated in load Filter combiner: F1 & F2 are limited Low insertion loss / less wasted power Has been used in Summitek factory PIM test equipment since 1996! Jan-20 Company Confidential
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Reduced Tx Range - No impact on customers
IM3 only possible in a subset of the full Uplink band MW82119A able to create all possible IM3 frequencies Jan-20 Company Confidential
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Reduced Tx Range - No impact on customers
Band Tx range Rx range Possible IM3 range MW82119A range Full coverage? 700U/L MHz MHz 776 – 787 MHz 698 – 716 MHz Not possible MHz MHz MHz YES 850 869 – 894 MHz 824 – 849 MHz 844 – 849 MHz 900 925 – 960 MHz 880 – 915 MHz 890 – 915 MHz 1800 1805 – 1880 MHz 1710 – 1785 MHz 1730 – 1785 MHz 1900 1930 – 1990 MHz 1850 – 1910 MHz 1870 – 1910 MHz PCS/AWS 2110 – 2155 MHz 1710 – 1755 MHz Jan-20 Company Confidential
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MW82119A – User interface RF indicator RF output Emergency stop button
Menu key On / Off key Arrow keys Touch screen display Keypad Jan-20 Company Confidential
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MW82119A – User interface Two USB ports External power input
AC adapter Automotive adapter Ethernet Remote control Two USB ports Power sensor Flash drive Mini USB port PC connectivity SMA (f) (w/Option 31) GPS antenna Jan-20 Company Confidential
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MW82119A – Remote control Control PIM test from remote location
Range: >100m (328FT) line-of-site Required: Firmware v1.04 (or greater) ZyXEL MWR102 router (or equiv.) Wireless Remote Access Tool application software Windows OS device with WiFi Jan-20 Company Confidential
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MW82119A – PIM vs. Time measurement
F1 and F2 fixed PIM magnitude vs. time Visual indication of PIM stability Peak PIM held for Pass/Fail Used for dynamic PIM testing Tapping on RF connections Limit Line Jan-20 Company Confidential
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MW82119A – Noise Floor measurement
External interference Measures IM frequency with transmitters turned OFF Check for external interference at IM frequency If interference > pass/fail limit, change F2 to move IM frequency Jan-20 Company Confidential
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MW82119A – Swept PIM measurement
Multiple PIM signals on combining in and out of phase 45 dB F1 fixed, F2 swept F2 fixed, F1 swept PIM magnitude vs. frequency Shows worst case PIM level 45 dB variation due to phasing! Jan-20 Company Confidential
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MW82119A – Distance-to-PIM™ (DTP) measurement
F1 fixed, F2 swept PIM magnitude vs. distance The fastest way to locate PIM See PIM beyond the antenna 6 markers + marker table Antenna PIM source 28 m (59 FT) beyond antenna Jan-20 Company Confidential
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MW82119A – Display options Default Colors Black and White Night Vision
High Contrast Invert Black and White Jan-20 Company Confidential
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MW82119A – Report Management
Manage PIM data using Line Sweep Tools (LST) Familiar user interface Add markers / adjust scale Create single site report combining: DTF DTP Return Loss PIM vs. TIME Jan-20 Company Confidential
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Upper main jumper to main
MW82119A – DTP / DTP overlay Overlay measurements using Line Sweep Tools (LST) Overlay on MW82119A in the field is in development Show “before” and “after” repair results Compare main and diversity path performance Evaluate changes over time Upper main jumper to main Output of Diplexer Lower jumper to main Antenna Jan-20 Company Confidential
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MW82119A – Designed for outdoor use
2 to 3 hour Battery Life Replaceable Same as other Anritsu HHs Production tested for reliability 50 hour burn-in 2 hour thermally cycled Designed tested for reliability HALT Test Vibration Test Shock Test Drop Test Designed and tested like all Anritsu Handhelds Jan-20 Company Confidential
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MW82119A – Standard Accessories
Part Number Description R Soft Carrying Case R Shoulder Strap R Connector Saver 633-75 Li-Ion Battery Pack R AC/DC Power Adapter (country dependent) AC Power Cable R Automotive 12V DC Adapter R Ethernet Cable, 213 cm (7 ft) USB Cable, 305 cm (10 ft) Anritsu Tool Box w/Line Sweep Tools DVD Disc Jan-20 Company Confidential
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2000-1716-R – Optional Accessory kit
Weather seal Foam cut-outs Removable upper tray Low PIM termination Low PIM, Armored test lead Cleaning supplies Torque wrench + Adjustable wrench RF adapter kit (Inside protective box) PIM standards (Inside protective box) Impact resistant, hard case Extra compartments for cables, charger, etc. Jan-20 Company Confidential
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760-259-R – Optional Transit case
Weather seal Retractable handle 4x snap latch Impact resistant, hard case Foam padding to protect contents Space for PIM Master inside soft case Lifting handles Storage boxes Contents shown for example only Wheels Jan-20 Company Confidential
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