SYM Technology RF Spectrum Performance Analysis

PowerPoint Presentation

Spectrum Performance MonitoringFernando TorrelioTodd Masters

AgendaSpectrum Analysis Connection Best PracticesWhere to connect spectrum analyzerCoupled test ports, direct connectionPros/Cons to different connection pointsService impacting, coupler directivity, fwd. or rev. measurementsPerformance considerationsNoise floor, noise figure, RBW, Max Input Power, Span

Best Practices for capturing spectral shotsBaselining, Pre-Game, Peak-Traffic, Post-Game, Optimization etc.

Performance Spectral ExamplesQualcommArrowheadSeaTacPanthers

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Where To Connect The iSpectrum

RX/TXRX/TX

1. From BTS to iSpectrum3. From Active DAS Tray to iSpectrum2. From in-line Splitter/Coupler to iSpectrum4. From DAS Monitoring Ports to iSpectrumiSpectrumDAS Point of InterfaceDAS System1234

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1. From BTS to iSpectrum2. From in-line Splitter/Coupler to iSpectrumiSpectrum12Coupled test port is best location for baseline down link signal characterization.View the condition of the signal source continuouslyThe RxA port of the radio is desired for the uplink path to observe the noise power at last stage of radio

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RX/TX

3. From Active DAS Tray to iSpectrumBase Station RadioDAS Point of Interface3The SYM SPOI provides access to DL and UL signals for proper baseline characterization.SPOI clamping prevents in band/out of band signals from overdriving active components.

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4. From DAS Monitoring Ports to iSpectrumiSpectrumDAS System4DAS coupled test ports of a DAS is the 4th stage where to connect 2G-IS24 Careful! Some DAS coupled test ports carry composite RF signal just prior to entering the optical stage.DL composite signals will have gone through combining and potentially frequency translation.UL composite signals do not include total attenuation of noise power before reaching radio.

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Pros/Cons to different connection pointsConsiderations with Directional CouplersCoupling FactorInsertion LossIsolation (When used for DL signal Monitoring)Uni-directional or Bi-directional

Coupling FactorIsolationInsertion Loss

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Pros/Cons to different connection pointsUse of Directional Couplers for DL MonitoringCoupling Factor (needs to be sufficient to protect circuitry)Insertion Loss (lower the better)Isolation (Sufficient enough to reduce uncertainty)Uni-directional (Dedicated Coupler for DL Monitoring)

DL Mon. PathIsolationInsertion Loss

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Pros/Cons to different connection pointsDirectional Couplers for UL MonitoringCoupling Factor (low coupling factor is desirable)Insertion LossIsolation (Simplex interface better than Duplex)Uni-directional (Dedicated for UL)

IsolationLow Coupling FactorInsertion Loss

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Spectrum Analyzer Performance ConsiderationsNoise FloorValidate with a Load Recording of a low noise floor is recommendedThis is a relative measurement providing assurance not accuracyNoise Floor should be low enough to discern signals below radio receiver levels which are tied to technology BW.Industry standard use of 30 KHz RBW This RBW has been traditionally been used since the days of TDMA where Radio BW was within 30 KHz.Good compromise between KTB noise rise above thermal and sweep speed.Noise FigureKnow your NF to know where the noise level actually isMaximum Input PoweriSPectrum is + 10 dBm for standard portsIndependent attenuation for Tx Demodulation can be applied

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iSpectrum Noise Floor Terminated to a Load

The plots above is a depiction of the iSpectrum noise floor terminated with a Load that provides confidence that noise floor measurements are not influenced by the unitChannel Power Density is defined power per Hz over defined bandwidth. The Channel Power Density with a Load is -162 dBm/Hz for 700 (Left plot) & AWS (right plot)

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You Cant Optimize What You Cant See

Two markers are activated to observe iSPectrum Noise FloorAverage noise level shown with markers is -119 dBm Note RBW 30 KHz with VBW 3 KHz

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A signal representing an interferer is activated which is 19 dB above the noise floor.

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With a coupling factor of 8 dB, the interferer is still discernable about 10 dB above the noise floor.

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With a coupling factor of 20 dB or higher, the interferer is no longer visible, hidden within the noise floor.The coupling factor dictated by the connection point to the iSpectrum will influence how much noise anomalies you can observe which impacts your ability to troubleshoot and optimize a DAS.

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UL & DL RF Signal Characterization & Best Practices

Preferred Signal Characterization is achieved when monitoring radio channel signals as close to the transmitter and receiver as possible.Direct connection to an eNodeB (41 dB coupling factor for DL analysis) (RxA port for UL analysis).This method provides best baseline signal characterization for reference purposes when optimizing and troubleshooting a system.

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Acceptable Signal Characterization using SYM ASPOI modulesHIGH coupling factors for DL analysis (High Power mode or Low Power mode)Independent LOW coupling factors for proper UL noise analysis Smart interface to the iSpectrum with alarm history and playback of spectral response up to 1 year.Auto Clamping provides DAS active stage protection from overdriving transmitters

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Acceptable Signal Characterization is achieved when monitoring signals using SYM ASPOI modules.ASPOI modules provide HIGH coupling factors for DL analysis (High Power mode and Low Power mode), independent LOW coupling factors for UL analysis to observe subtle anomalies and correlation effects.The ASPOI also provides a smart interface to the iSpectrum with alarm history and access to playback of spectral response for any port up to 1 year.Auto Clamping is a ASPOI feature that provides DAS active stage protection from overdriving transmitters when reset or changed out.

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An alternative location to signal characterization is directly to a DASSome DAS equipment have band specific monitoring ports from which to connect the iSPectrum for DL and separately UL signal analysisAwareness of the coupling factor needs to be considered to avoid masking important low signal level anomaliesComposite signal ports are a compromise because they do not represent the stage nearest the radio to evaluate performance

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Noise Floor Measurement Primer for UL

Noise Floor Alarm Functionality is based on 10 MIN Hold samples with power reading updates within the selected BW to check noise MIN Hold response against Noise Floor LimitAll other traces are standard; Max Hold, Live Trace overlayed on same channel

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For Noise power Alarm functionality, the iSpectrum uses a minimum hold (trace) function. The iSpectrum MIN Hold is updated every ten measurements. The noise power reading within the selected bandwidth is taken and checked against the noise limit to update alarm status. This method checks noise floor levelwithout having normal traffic influence. So, if (periodic) 10 times of minimum hold trace doesn't exceed a noise floor threshold level, then noise floor alarm won't be generated.

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Channel Power Measurement Primer for DL

The Channel Power calculation is a function of span, RBW the point count within the selected BW and the linear sum (mW) of the spectral power within the selected BW.Channel Power Block is selectable to fit radio channel signal BW. Features such as Max Hold, Min Hold and Live Trace can all be displayedNote Channel Power Density is also available

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Channel Power measurements are calculated for the selected frequency bandusing the formula below:CH_Power = 10*log10((span/RBW)(1.0/pointcount)*mwsum)RBW: RBW on the custom profilePointcount: Total number of points within the selected bandwidth (percentage of span of 1000 points)Please note that 1000 points equals the full spectrum bandwidth on the spectrum display.mwsum: Total summed spectral power for the selected bandwidth (using linear Milliwatt, mW unit)

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Baseline Signal Characterization

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Best Practices for Capturing UL Spectral Shots

Capturing of UL Baseline signals should take place when signal source is getting commissioned into system. Capturing of a Radio Channel terminated to a load provides a proper reference from which any activity can be compared too.Baseline captures of existing systems should be taken with minimal activity on the radio channel.

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Best Practices for Capturing DL Spectral Shots

Capturing of DL Baseline signals should also take place when signal source is getting commissioned into system. Capturing of a Radio Channel with (OCNS or AIGL) activated may be used to set the iSPectrum Alarm BlocksBaseline captures of existing systems should be taken with minimal activity on the radio channel.

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Best Practices for Pre-Game Captures - Correlation

Capturing the UL Noise activity prior to a Game or Event provides a perspective to review correlation of effects between SISO and MIMO paths or DL and UL signals.The SISO path clearly shows a PIM signature while not present in the MIMO path indicating PIM is internal to the system. Notice how system sensitivity is enhanced by low coupling factor

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As the UE activity surges, in band noise rises correspondinglyThe receiver filter in the SISO path is not as effective as the MIMO pathThe MIMO out of band noise response provides reference to target for the poor SISO path response

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An AWS band early pre-game capture shows an unusual response across entire span in the MIMO path not present in the SISO path.This effect was present when switching ports and verified on external spectrum analyzer validating it is associated to respective receiver.

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Unusual noise response not present in alternate sector MIMO pathA couple of observations; out of band noise rise in the SISO path in alarm denotes possible near far interference taking place.More in band noise rise of the SISO path compared to the MIMO path not a significant difference but something to watch

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A check of all radio channels (DL and UL) will discover several anomalies at a glance. Some may need further investigation.Noise rise in adjacent carrier UL band possibly caused by near far effect Oscillation taking place in upper band only in MIMO pathBoth could be issues if these effects breach operational band

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Best Practices for Game Time Captures

At halftime, the DL radio channel activity is near its peakThis can be determined by the close proximity of the Green Live Trace to the Purple Max Hold Trace. The signal shape of all radio channels shows no presence of ACLRChannel Power Density is used to check power balancing for NH systems

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An AWS band capture at halftime continues to show the high level of activity (Live Trace near the Max Hold trace)Note the Channel Power Density indicator for both SISO and MIMO paths are within 0.9 dBm/Hz which is pretty well balancedNo presence of any ACLR. This is expected but, what does the remote ACLR response look like with this much activity

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Significant Game Captures

Qualcomm Stadium Game Capture Imbalance?

On left side, Sector 5 700 MHz UL noise response for Rx1 and Rx2 rises due to activity however balanced with no sign of PIM nor interference for both layers. However, the Sector 10 700 MHz UL noise response for Rx2 is imbalanced from Rx1 with a 10 dB higher noise responseThis is compared to baselines to understand if changes are expected or not

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Comparing last captures to their BASELINES

Having some baselines to compare with provides a good perspective from which to compare changes whether they are expected or not and why

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In the AWS UL band Sector 5 and 10 AWS Rx1 & Rx2 UL IN BAND noise response is generally balanced while activity takes place during Jan. 1 Game. An out of band noise alarm does appear in the S5 AWS Rx2 response which is intermittent and occurring when activity is at a peak.

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How About Some Tx Demodulation 700 EVM

The iSpectrum Tx demodulation capability provides a means to observe EVM for a given signal source. The left side image shows a polar EVM display with a measurement value associated to Cell ID and describing MIMO layer. The right side is a summary of the Tx Demodulation matching the graphical response

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The iSpectrum Tx demodulation capability provides a means to observe EVM for a given signal source. The left side image shows a polar EVM display with a measurement value associated to Cell ID and describing MIMO layer. The right side is a summary of the Tx Demodulation matching the graphical response. The KPI report provides an EVM taken periodically over time to observe any degradation such as during an event.

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How About Some Tx Demodulation AWS EVM

The EVM measurements taken as baselines prior an event are expected to be very low 50% indicated Radio Channel Quality is Compromised

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The iSpectrum Tx demodulation capability provides a means to observe EVM for a given signal source. The left side image shows a polar EVM display with a measurement value associated to Cell ID and describing MIMO layer. The right side is a summary of the Tx Demodulation matching the graphical response. The KPI report provides an EVM taken periodically over time to observe any degradation such as during an event.

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Does EVM change when Game Time Occurs - 700

EVM degradation is expected when activity takes place as shown aboveDespite an EVM of 12.7%, a 16 QAM can still be demodulatedMajor Question is what does EVM look like at the remote end?

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Does EVM change when Game Time Occurs - AWS

The AWS Tx demodulation of Sector 1 is at 16.6% yet a 64QAM demodulation is possible. This is soon to change however as bits of information will be lost in translation. The MCS detecting this will reduce modulation adjusting it to the Quality of the Radio Channel

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NFL

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19:19 Ports 13-14

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Power Fail

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Open Connection

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Adjacent Noise

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PIM

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Adjacent Channel Power Threshold Breach

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Interference

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Dual Interferers

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The Productivity of the SYM iSpectrum 2G-IS24

Spectrum Use CasesUsing the iSpectrum gives you access to the Super User community to share In-Building issues nationwide with other performance teams

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Spectral Performance KPI

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KPI Reporting

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Analyzed Data

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Replay Data To Pin Point Issue

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SummaryBest practices for Spectral Monitoring provides insight to real performance and visibility into the signal quality

Productivity is enhanced with the use of the iSpectrum KPI Report capability to evaluate consolidated spectral performance at any time 24/7

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Thank Youwww.symtechnology.xom

span

Span_CH_Power = 10*log10((span/RBW)*(1.0/pointcount)* mwsum)

1000 points for full span(80 MHz)

Noise Block Start

Noise Block Stop

300 points (24 MHz)

NFPower(dBm/Hz) = Span_CH_Power-(10*log10(span))

Total summed spectral power for 300 points

Min. Hold Spectrum

Minimum Hold Trace (10 Times)

Span for CH. Powermeasurement

CH_Power = 10*log10((span/RBW)*(1.0/pointcount)* mwsum)

1000 points for full span (20 MHz)

CH. Power Block Stop

CH. Power Block Start

500 points (counts)(10MHz)

Total summed spectral power for 500 points