docPassive Intermodulation (PIM) testing
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Passive Intermodulation (PIM) testing
Passive Intermodulation (PIM) testing Oct-13 Company Confidential Slide 1 What is Passive Intermodulation (PIM) TX signals at site Passive Intermodulation (PIM) F1 F2 Passive Intermodulation (PIM) 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 Oct-13 Company Confidential Slide 2 What is a non-linear junction? Linear junctions Current • Current increases linearly with applied voltage. • High pressure, metal-to-metal contacts • Welded or soldered connections. Voltage Non-Linear junctions • Current does not increase linearly with voltage. • Low pressure, metal-to-metal contacts Current • Oxide layers on metal surfaces • Arcing across small air gaps or cracks Voltage Oct-13 Company Confidential Slide 3 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 Oct-13 Company Confidential Slide 4 What does PIM look like at the site? Broad band interference Oct-13 Company Confidential Narrow band spikes Slide 5 What does PIM look like to the operator? BUSY QUIET BUSY High average noise level QUIET PIM Repair Lower average noise level Oct-13 Company Confidential Slide 6 Where does PIM occur? F1 F2 2*F1–1*F2 2*F2–1*F1 3*F1–2*F2 3*F2–2*F1 4*F2–3*F1 4*F1–3*F2 5*F2–4*F1 5*F1–4*F2 IM 9 IM 7 IM 5 IM 3 IM 3 IM 5 IM 7 • PIM occurs at mathematical combinations of the Tx frequencies Oct-13 Company Confidential • F1 = 1930 MHz • IM3 = (2*1930) – (1*1945) = 1915 MHz IM3 = (2*1945) – (1*1930) = 1960 MHz • IM5 = (3*1930) – (2*1945) = 1900 MHz IM5 = (3*1945) – (2*1930) = 1975 MHz • IM7 = (4*1930) – (3*1945) = 1885 MHz IM7 = (4*1945) – (3*1930) = 1990 MHz • IM9 = (5*1930) – (4*1945) = 1870 MHz IM9 = (5*1945) – (4*1930) = 2005 MHz F2 = 1945 MHz IM 9 What is the bandwidth of PIM signals? F1 F2 200 KHz 200 KHz 600 KHz 600 KHz 1 MHz 1 MHz 1.4 MHz 1.4 MHz 1.8 MHz 1.8 MHz IM 9 IM 7 IM 5 IM 3 IM 3 IM 5 • PIM bandwidth increases as carrier bandwidth increases • PIM bandwidth increase with PIM order Oct-13 Company Confidential • F1 = 200 KHz • IM3 bandwidth = 3* 200 KHz = 600 KHz • IM5 bandwidth = 5* 200 KHz = 1000 KHz = 1 MHz • IM7 bandwidth = 7 * 200 KHz = 1400 KHz = 1.4 MHz • IM9 bandwidth = 9 * 200 KHz = 1800 KHz = 1.8 MHz F2 = 200 KHz IM 7 IM 9 Can one wide band carrier generate PIM? 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 ! • The wideband signal is composed of individual sub-carriers Oct-13 Company Confidential • 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 5 MHz Why are we just now seeing this problem? Before: -50 dB -50 dB Simple antennas Single bands per feeder Narrow carrier bandwidths Tx and Rx on separate feeders >50 dB Tx/Rx isolation! PIM Rx Oct-13 Company Confidential Slide 10 Tx Rx 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 PIM ▪ No Tx/Rx isolation Tx/Rx 850/1900 Oct-13 Company Confidential Slide 11 Tx/Rx 850/1900 What is the solution? LTE Eliminate non-linearity so that multiple frequencies can peacefully co-exist! Choose site locations wisely Choose RF components wisely Install carefully CDMA Verify linearity using a PIM test Oct-13 Company Confidential Slide 12 How does PIM test equipment work? Tx combiner F1 Must be low PIM ! Duplexer DUT TX F2 Receiver PIM IM RX Transmits two test frequencies High power (2x 20W typical) Measures signal level at the IM frequency Oct-13 Company Confidential Slide 13 Load Why do we measure IM3 ? F1 F2 IM 3 IM 3 A IM 11 Noise Floor A IM 9 IM 7 IM 5 IM 5 BTS Uplink (Rx) IM 7 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 Oct-13 Company Confidential Slide 14 What test frequencies should I use? Exact frequencies used not critical F1 & F2 spaced far apart to put IM3 in Rx band Guard band frequencies recommended for fixed tone tests F1, F2 & IM3 must all be able to pass through the system Oct-13 Company Confidential Slide 15 What might block PIM test frequencies? Antennas 698-896 MHz 1710-2170 MHz Tower Mounted Amplifiers (TMA) Filters Lightning surge protectors Sweep test to verify Use correct PIM test set 1900 Oct-13 Company Confidential 850 By-pass frequency limiting devices Slide 16 What is the preferred test process? START Site Master PIM Master Repair Oct-13 Company Confidential Sweep test DTF Repair Noise Floor Static Dynamic PIM vs. TIME PIM vs. TIME DTP Repair Slide 17 Save Results END Anritsu PIM test solutions Oct-13 Company Confidential Slide 18 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 Three models: Spectrum Master 850 MHz, 900 MHz, 1900/2100 MHz Oct-13 Company Confidential Slide 19 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™ Nine models: 700 MHz (U/L), 800 MHz, 850 MHz, 900 MHz 1800 MHz, 1900 MHz, 1900/2100 MHz No external controller required 2100 MHz, 2600 MHz Oct-13 Company Confidential Slide 20 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 Oct-13 Company Confidential Slide 21 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 Oct-13 Company Confidential Slide 22 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 Oct-13 Company Confidential Slide 23 MW82119A - Key features Full-featured PIM test set! 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) Residual PIM >-117dBm @ 2x 43dBm Distance-to-PIM™ YES PIM vs. Time YES Swept PIM YES Noise floor YES Remote Control YES GPS option YES * - Weight varies by frequency option Oct-13 Company Confidential Slide 24 MW82119A – Available models Frequency Option Model Number F1 F2 IM 700 MHz (L/U) MW82119A-0700 734 – 734.5 MHz 745 – 766 MHz 698 – 716 MHz / 779.5 – 804 MHz 800 MHz MW82119A-0800 791 – 795 MHz 811.5 – 821 MHz 832 – 862 MHz 850 MHz MW82119A-0850 869 – 871.5 MHz 881.5 – 894 MHz 824 – 849 MHz 900 MHz MW82119A-0900 925 – 937.5 MHz 951.5 – 960 MHz 880 – 915 MHz 1800 MHz MW82119A-0180 1805 – 1837.5 MHz 1857.5 – 1880 MHz 1710 – 1785 MHz 1900 MHz MW82119A-0190 1930 – 1932.5 MHz 1950 – 1990 MHz 1870 – 1910 MHz 1900/2100 MHz MW82119A-0192 1930 – 1935 MHz 2110 – 2155 MHz 1710 – 1755 MHz 2100 MHz MW82119A-0210 2110 – 2112.5 MHz 2130 – 2170 MHz 1920 – 1980 MHz / 2050 – 2090 MHz 2600 MHz MW82119A-0260 1930 – 1932.5 MHz 1950 – 1990 MHz 1870 – 1910 MHz Oct-13 Company Confidential Slide 25 MW82119A – User interface RF indicator RF output Emergency stop button Menu key On / Off key Arrow keys Touch screen display Oct-13 Company Confidential Keypad Slide 26 MW82119A – User interface External power input Ethernet AC adapter Remote control Automotive adapter Two USB ports Mini USB port Power sensor PC connectivity Flash drive SMA (f) (w/Option 31) GPS antenna Oct-13 Company Confidential Slide 27 MW82119A – Remote control Control PIM test from remote location Firmware v1.04 (or greater) ZyXEL MWR102 router (or equiv.) Download application from Anritsu website and install on any Windows OS device with WiFi Range: >100m (328FT) line-of-site Oct-13 Company Confidential Slide 28 MW82119A – PIM vs. Time measurement F1 and F2 fixed Tapping on RF connections Limit Line PIM magnitude vs. time Visual indication of PIM stability Peak PIM held for Pass/Fail Used for dynamic PIM testing Oct-13 Company Confidential Slide 29 MW82119A – Noise Floor measurement Measures IM frequency with transmitters turned OFF External interference Verify no external interference at test frequency Oct-13 Company Confidential Slide 30 MW82119A – Swept PIM measurement F1 fixed, F2 swept Multiple PIM signals on combining in and out of phase F2 fixed, F1 swept PIM magnitude vs. frequency 45 dB Shows worst case PIM level 45 dB variation due to phasing! Oct-13 Company Confidential Slide 31 MW82119A – Distance-to-PIM™ (DTP) measurement F1 fixed, F2 swept Antenna PIM source 28 m (59 FT) beyond antenna PIM magnitude vs. distance The fastest way to locate PIM See PIM beyond the antenna 6 markers + marker table Oct-13 Company Confidential Slide 32 MW82119A – Enhanced Resolution DTP Standard resolution reports one PIM source at 16.7m Enhanced resolution reports two PIM sources, 15.7m and 17.4m Improves ability to see closely spaced PIM sources Predictions clearly marked by red bars Location for each prediction automatically displayed Speeds DTP trace interpretation 16m 2m load 0m Oct-13 Company Confidential 2x PIM sources 16m 18m Slide 33 MW82119A – Distance-to-PIM™ (DTP) overlay Compare two DTP measurements Overlay trace Automatically displays distance between peaks Active trace Relative distance Useful for: Showing “before” & “after” results Showing distance to object in front of antenna Saving the measurement keeps both traces for reports Oct-13 Company Confidential Slide 34 MW82119A – Display options Default Colors Black and White Night Vision High Contrast Invert Black and White Oct-13 Company Confidential Slide 35 MW82119A – Report Management Manage PIM data using Line Sweep Tools (LST) Familiar user interface Add markers / adjust scale Single site report combining VSWR & PIM results Tabular PIM report option Oct-13 Company Confidential Slide 36 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 Designed and tested like all Anritsu Handhelds Oct-13 Company Confidential Drop Test Slide 37 MW82119A – Standard Accessories Part Number Description 2000-1712-R Soft Carrying Case 2000-1714-R Shoulder Strap 1091-387-R Connector Saver 633-75 Li-Ion Battery Pack 40-187-R AC/DC Power Adapter (country dependent) AC Power Cable 806-141-R Automotive 12V DC Adapter 2000-1371-R Ethernet Cable, 213 cm (7 ft) 3-2000-1498 USB Cable, 305 cm (10 ft) 2300-530 Anritsu Tool Box w/Line Sweep Tools DVD Disc Oct-13 Company Confidential Slide 38 Optional Accessories 2000-1745-R - Backpack Accessory Kit 760-259-R – Transit case (Holds MW82119A only) 760-265-R – Transit case (Holds MW82119A plus accessories) (accessories not included) 2000-1746-R - Hard Case Accessory Kit Slide 39 Oct-13 Company Confidential PIM Master MW82119A Light weight Battery operated Full featured PIM Analyzer Oct-13 Company Confidential Slide 40 PIM Master MW82119A Demonstration Oct-13 Company Confidential Slide 41
