Digital noise floor monitoring (DNFM)

Digital noise floor monitoring (DNFM) Riverside County Project Report Site monitored: March 22, 2010

Table of Contents Revision History... 1 Digital Noise Floor Monitoring Overview... 2 What is Digital Noise Floor Monitoring (DNFM)?... 2 What Digital Noise Floor Monitoring does not do... 3 Frequency Noise Report... 4 Frequency Sensitivity and Noise (Spectrum Noise Report)... 4 Frequency Standard Deviation:... 5 Frequency Coverage Reliability:... 6 Receive Frequency Assessment Matrix... 7 Coverage Prediction Utilizing Noise Summary Data... 8 Appendix A - Spectrum Noise Report... 10 Appendix B - Frequency Noise Reports... 13 Frequency 799.53125 MHz... 14 Frequency 800.03125 MHz... 15 Frequency 801.14375 MHz... 16 Frequency 801.44375 MHz... 17 Frequency 803.21250 MHz... 18 Frequency 804.66875 MHz... 19 Appendix C - Noise Floor Data Evaluation... 20 Page i

Revision History Revision Date of revision Written by Approved by Description of Change/Notes Original 4/19/2010 Ron Jakubowski Al Yerger Original release A 4/23/2010 Ron Jakubowski Al Yerger Normalized Table 3 System Values without wider-bandwidth HPD channel B 6/10/2010 Bill Tobin Al Yerger Updated ToC, Clarified HPD channel in Table 3 C 6/23/2010 Bill Tobin Al Yerger Updated ToC Page 1

Digital Noise Floor Monitoring Overview What is Digital Noise Floor Monitoring (DNFM)? Knowing what the conditions are at a radio site is critical to the success of the project. One very important aspect of site design is estimating the noise floor that exists on the desired receive frequencies. Because it is on frequency, the noise that exists on channel must be filtered at the source and cannot be filtered in front of the receiver. In some cases, the source of the noise can be investigated and resolved and in other cases it cannot. Either way, it is best to know that it exists and to what level so that prudent decisions can be made. It is important to understand that conventional measurement techniques of noise floor monitoring can be prone to difficulties. Typical spectrum analyzers will produce the desired results and in the best of circumstances, will only allow you to measure the noise floor down to about -100 dbm. In order to accomplish the very sensitive measurements that are required (better than -120 dbm), a very sharp filter must be utilized. In addition, if multiple receive frequencies need to be monitored, this filter will need to be retuned due to its selectivity. This is where Digital Noise Floor Monitoring (DNFM) comes in. Using an antenna, bandpass filter, spectrum analyzer, computer, special software, and a computer controlled crystal filter, noise floor data is collected for 24 hours. The data consists of an extraordinary amount of information for the frequencies included in the monitoring plan. A report is generated for each of these frequencies and is uploaded to the Spectrum Fingerprint server for 24/7 access. Software Control & Storage Media GPIB Antenna Ultra Q & AMP Spectrum Analyzer Figure 1: Typical Digital Noise Floor Monitoring Setup Page 2

What Digital Noise Floor Monitoring does not do DNFM focus on spectral activity below -80 dbm in order to determine just how good (or bad) the noise floor will be on a given receive frequency. Since strong, off frequency carriers can desensitize a receiver, it is equally important to understand what High Level Carriers (HLC s) are within striking distance of the receive system. Spectrum Fingerprinting is quite similar to DNFM in that it collects spectral data for 24 hours but it focuses on the HLC s above -80 dbm. Having an accurate indication of the noise floor for your receiver means you can change frequencies if need be or you can investigate the matter further (Interference Mitigation) to determine if the high noise floor problem can be resolved. Resolving these issues before infrastructure is at the site is the most financially prudent approach. DNFM combined with Spectrum Fingerprinting provides a tremendous amount of information to avoid costly mistakes with frequencies and design the most accurate system possible. Neither of these services is intended to resolve interference problems by themselves and if Interference Mitigation is the objective, these services can be very useful tools in the process. There is much more detailed information with regard to Spectrum Fingerprinting and other services at http://spectrumfingerprint.mot.com so please utilize this web site if a more in depth explanation is required. 0 Spectrum Fingerprinting focuses on the High Level Carriers above -80 dbm -80 Difference between noise floor of spectrum analyzer and test RX sensitivity is 50-60 db -140 Figure 2: Expanded Spectrum Analyzer Display Page 3

Frequency Noise Report Frequency Sensitivity and Noise (Spectrum Noise Report) The yellow bars on this graph display the average site noise for each frequency over the monitoring period. The noise is referred to as Composite Noise as it could contain noise from multiple sources including the test equipment. Displayed noise levels above the system Static Sensitivity are primarily external noise. Under these conditions, the noise contribution from the test equipment will be insignificant. The green bars on the graph display the static system effective sensitivity (ERS). This is simply the static composite noise increase by the Cs/N required to obtain the sensitivity criteria, 12 db SINAD or 5% BER. Figure 3: Frequency Spectrum (Sample) Page 4

Frequency Standard Deviation: The blue bars on this graph show the standard deviation of the noise for each frequency over the monitoring period. Standard deviation is a statistical measurement that describes how the noise changes over the monitoring period. The standard deviation can be used to determine the probability of the noise exceeding a given value. The red line displays the degradation for each frequency. The degradation is simply the system effective receiver sensitivity (ERS) compared to the system static sensitivity. While this value is not directly related to the noise standard deviation the graph illustrates that the two usually track together. Larger variations in the noise as represented by a high standard deviation usually result in a greater average system degradation. The System value shown below is the average of all other values shown in the graph. Degradation Figure 4: Channel Degradation and Deviation over 24Hrs (Sample) Page 5

Frequency Coverage Reliability: The green bars on this graph display the average noise relative to the theoretical noise floor (KTB). This is the value required by Hydra. The orange bars show the total noise value, relative to KTB, that must be entered into Hydra to obtain the desired noise probability. For example, if the noise probability is 95% then the actual site noise, relative to KTB, will be less than or equal to the total value displayed on the graph 95% of the time. The System value shown below is the average of all other values shown in the graph. Figure 5: Frequency Coverage Reliability - usually 95% (Sample) Page 6

Receive Frequency Assessment Matrix The Receive Frequency Assessment Matrix below takes into account the results of Spectrum Fingerprinting which focuses on signals above -80 dbm as well as Digital Noise Floor Monitoring which concentrates on signals below -80 dbm. The following rules and assumptions were used to evaluate these frequencies: Frequencies with >10 db noise degradation more than 10% of the time could be considered higher risk. The lower-level signals will be captured by the users of the new system. High level carriers are off frequency to the desired receive frequency and depending on the frequency separation from the desired and signal strength, filters in front of the receiver may or may not be implemented to allow the receiver to coexist with the carrier. In some cases, these high level carriers may require many filters to insure adequate carrier suppression and therefore be cost prohibitive. Thus, higher risk Carrier appraisals may be assessed in situations when the high level carriers are either too close to filter or cost prohibitive. Proposed Receive Frequency Carrier Noise Risk 799.53125 MHz LOW LOW 800.03125 MHz LOW LOW 801.14375 MHz LOW LOW 801.44375 MHz LOW LOW 803.21250 MHz LOW LOW 804.66875 MHz LOW LOW Table 1: Receive Frequency Risk Assessment Table It is possible to perform an interference investigation to determine the cause of a high noise floor if a specific receive frequency cannot be changed. Page 7

Coverage Prediction Utilizing Noise Summary Data The Average External NoiseKTB value from Table 3 can be entered in to Hydra to assist in coverage prediction as shown below: From Motorola s Interference Considerations in RF Design 2008 (TTS104) Measurements based on the following receiver characteristics: Cs/N NF: KTb KTb 7.6 db 4 db 137 dbm (5.4 KHz ENBW) 132 dbm (16.1 KHz ENBW)* Table 2: Test Receiver Characteristics *indicates High Performance Data channel, as specified by Motorola Page 8

Average Sensitivity External Ext Noise Ext Noise Average Adjustment/ Frequency Noise KTB Avg Power Min Power Static ERS Degradation 799.531250 MHz 6.38 db -134.02 dbm -136.19 dbm -122.67 dbm 2.38 db 800.031250 MHz 6.69 db -133.31 dbm -135.56 dbm -122.36 dbm 2.69 db 801.143750 MHz 6.70 db -133.30 dbm -135.66 dbm -122.35 dbm 2.70 db 801.443750 MHz 6.43 db -133.89 dbm -135.83 dbm -122.62 dbm 2.43 db 803.212500 MHz 6.26 db -129.56 dbm -130.73 dbm -118.05 dbm 2.26 db 804.668750 MHz 6.23 db -134.39 dbm -136.72 dbm -122.82 dbm 2.23 db System 6.49 db -133.76 dbm -134.39 dbm -122.56 dbm 2.49 db *based on P25 static sensitivity of -125.05 dbm (voice) or -120.31 dbm (HPD) Table 3: Spectrum Noise Summary Data Page 9

Appendix A - Spectrum Noise Report Page 10

Frequency Spectrum Static ERS KTB Composite Noise Static Sensitivity -115-125 -135 799.531250 MHz 800.031250 MHz 801.143750 MHz 801.443750 MHz 803.212500 MHz 804.668750 MHz Figure 6: Frequency Spectrum Please note that channels with wider bandwidth (e.g., HPD) will exhibit a higher noise floor measurement due to the admittance of more noise. Page 11

10 db Frequency Standard Deviation Std Dev Degredation 5 db 0 db 799.531250 MHz 800.031250 MHz 801.143750 MHz 801.443750 MHz 803.212500 MHz 804.668750 MHz System Figure 7: Channel Degradation and Deviation Over 24 Hrs 10 db Frequency Coverage Reliability Noise Reliability is the amount of additional Signal Needed to maintain your coverage reliability Noise Reliability External NoiseKTB 5 db 0 db 799.531250 MHz 800.031250 MHz 801.143750 MHz 801.443750 MHz 803.212500 MHz 804.668750 MHz System Figure 8: Frequency Coverage Reliability Page 12

Appendix B - Frequency Noise Reports The noise floor looks relatively clean. There are some minor elevations visible around the 8 a.m. time frame that appear to affect all frequencies at that time. Page 13

Frequency 799.53125 MHz -105 db 799.53125 MHz Frequency Sensitivity Ext Noise AVG Pow er KTB Static ERS Static Sensitivity -110 db -115 db -120 db -125 db -130 db -135 db -140 db 10 db 799.53125 MHz Degradation Summary Std Dev Noise Reliability Degredation External NoiseKTB 5 db 0 db 100% 799.53125 MHz Carrier Occupancy Occupancy Count 10 90% 80% 70% 60% 50% 5 40% 30% 20% 10% 0% 12:03 AM 8:39 AM 5:15 PM 0 Page 14

Frequency 800.03125 MHz -105 db 800.03125 MHz Frequency Sensitivity Ext Noise AVG Pow er KTB Static ERS Static Sensitivity -110 db -115 db -120 db -125 db -130 db -135 db -140 db 10 db 800.03125 MHz Degradation Summary Std Dev Noise Reliability Degredation External NoiseKTB 5 db 0 db 100% 800.03125 MHz Carrier Occupancy Occupancy Count 10 90% 80% 70% 60% 50% 5 40% 30% 20% 10% 0% 12:03 AM 8:39 AM 5:15 PM 0 Page 15

Frequency 801.14375 MHz -105 db 801.14375 MHz Frequency Sensitivity Ext Noise AVG Pow er KTB Static ERS Static Sensitivity -110 db -115 db -120 db -125 db -130 db -135 db -140 db 10 db 801.14375 MHz Degradation Summary Std Dev Noise Reliability Degredation External NoiseKTB 5 db 0 db 100% 801.14375 MHz Carrier Occupancy Occupancy Count 10 90% 80% 70% 60% 50% 5 40% 30% 20% 10% 0% 12:03 AM 8:39 AM 5:15 PM 0 Page 16

Frequency 801.44375 MHz -105 db 801.44375 MHz Frequency Sensitivity Ext Noise AVG Pow er KTB Static ERS Static Sensitivity -110 db -115 db -120 db -125 db -130 db -135 db -140 db 10 db 801.44375 MHz Degradation Summary Std Dev Noise Reliability Degredation External NoiseKTB 5 db 0 db 100% 801.44375 MHz Carrier Occupancy Occupancy Count 10 90% 80% 70% 60% 50% 5 40% 30% 20% 10% 0% 12:03 AM 8:39 AM 5:15 PM 0 Page 17

Frequency 803.21250 MHz -105 db 803.21250 MHz Frequency Sensitivity Ext Noise AVG Pow er KTB Static ERS Static Sensitivity -110 db -115 db -120 db -125 db -130 db -135 db -140 db 10 db 803.21250 MHz Degradation Summary Std Dev Noise Reliability Degredation External NoiseKTB 5 db 0 db 100% 803.21250 MHz Carrier Occupancy Occupancy Count 10 90% 80% 70% 60% 50% 5 40% 30% 20% 10% 0% 12:03 AM 8:39 AM 5:15 PM 0 Page 18

Frequency 804.66875 MHz -105 db 804.66875 MHz Frequency Sensitivity Ext Noise AVG Pow er KTB Static ERS Static Sensitivity -110 db -115 db -120 db -125 db -130 db -135 db -140 db 10 db 804.66875 MHz Degradation Summary Std Dev Noise Reliability Degredation External NoiseKTB 5 db 0 db 100% 804.66875 MHz Carrier Occupancy Occupancy Count 10 90% 80% 70% 60% 50% 5 40% 30% 20% 10% 0% 12:03 AM 8:39 AM 5:15 PM 0 Page 19

Appendix C - Noise Floor Data Evaluation There are two key elements to the data when evaluating the noise floor of a receive frequency: 1. Table 1 Spectrum Noise Summary Data this provides the data necessary to enter into Hydra. 2. Appendix B Frequency Noise Reports as illustrated in the example below, it is important to analyze the frequency noise report of each receiver. -95 db 151.31000 MHz Frequency Sensitivity Nebraska - Huntsman - 040709 Ext Noise AVG Pow er KTB Static ERS Static Sensitivity -100 db -105 db -110 db -115 db -120 db -125 db -130 db -135 db -140 db Figure 9: Frequency Noise Report (Sample) Since the Noise Floor Monitoring data is collected for 24 hours, it can vary considerably during that period and/or it can experience spikes due to transmitter activity. Does the noise floor elevate during certain times of the day? Is there a time of day when the noise floor is relatively low or the spikes are minimal? Like Spectrum Fingerprint data, Noise Floor Monitoring data is not intended to identify interference; it is intended to verify its existence. This data can be quite useful to the RF Engineer who investigates the interference but additional time would need to be spent at the site to identify the source of the interference. Page 20

Broadband Noise Example Constant sources of RF such as broadcast transmitters can create an elevated noise floor at a site and the characteristics would typically be: minimal variation during the monitoring period can impact many receivers -65 db 154.25000 MHz Frequency Sensitivity Navy Europe - Mt Camaldoli - 042208 Ext Noise AVG Pow er KTB Static ERS Static Sensitivity -70 db -75 db -80 db -85 db -90 db -95 db -100 db -105 db -110 db -115 db -120 db -125 db -130 db -135 db -140 db Figure 10: Broadband Noise Example Missing Data If there is not 24 hours of data, the missing data is represented with a straight line. In the example below, the data collection began at approximately 12:30PM and a power outage occurred at 3:30AM. -95 db 163.15000 MHz Frequency Sensitivity Wyolink - Cheyenne Water Tank - 110909 Ext Noise AVG Pow er KTB Static ERS Static Sensitivity -100 db -105 db -110 db -115 db -120 db -125 db -130 db -135 db -140 db Figure 11: Missing Data Example Page 21

Bird Electronic License Agreement 1. GRANT OF LICENSE. BIRD TECHNOLOGIES GROUP SITE OPTIMIZATION SERVICES ( BIRD SOS ) GRANTS THE RIGHT TO USE THIS COPY OF THE BIRD SOS SPECTRUM FINGERPRINTING REPORT FOR INTERFERENCE ANALYSIS, FOR FUTURE REFERENCE, AND FOR A BETTER UNDERSTANDING OF THE CONDITIONS, TECHNIQUES AND CONCEPTS CONTAINED HEREIN. BIRD SOS PRESENTS THIS MATERIAL FOR THE EXPRESS PURPOSE OF INTERFERENCE MITIGATION TO THOSE INDIVIDUALS WHO WILL BE CORRECTING SAID INTERFERENCE, FOR RESEARCH AND DEVELOPMENT, FOR TESTING AND FIELD MAINTENANCE, OR IN ANY OTHER TECHNICAL CAPACITY. 2. LIMITATION OF LIABILITY. BIRD S LIABILITY (WHETHER UNDER THE THEORIES OF BREACH OF CONTRACT OR WARRANTY, NEGLIGENCE, OR STRICT LIABILITY) FOR THIS MATERIAL SHALL BE LIMITED TO REPLACING ANY PARTS FOUND TO BE IN ERROR. 3. DISCLAIMER OF CONSEQUENTIAL DAMAGES. IN NO EVENT SHALL BIRD SOS BE LIABLE FOR CONSEQUENTIAL DAMAGES ARISING OUT OF OR IN CONNECTION WITH THIS AGREEMENT, INCLUDING WITHOUT LIMITATION, BREACH OF ANY OBLIGATION IMPOSED ON BIRD SOS HEREUNDER OR IN CONNECTION HEREWITH. CONSEQUENTIAL DAMAGES FOR PURPOSES HEREOF SHALL INCLUDE WITHOUT LIMITATION LOSS OF USE, INCOME OR PROFIT, OR LOSSES SUSTAINED AS THE RESULT OF INJURY, (INCLUDING DEATH TO ANY PERSON) OR LOSS OF OR DAMAGE TO PROPERTY (INCLUDING WITHOUT LIMITATION PROPERTY HANDLED OR PROCESSED. BUYER SHALL INDEMNIFY BIRD SOS AGAINST ALL LIABILITY, COST EXPENSE, WHICH MAY BE SUSTAINED BY BIRD SOS ON ACCOUNT OF ANY SUCH LOSS, DAMAGE OR INJURY. 4. NO OTHER WARRANTIES. BIRD SOS DISCLAIMS ALL OTHER WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, WITH RESPECT TO THE ACCOMPANYING WRITTEN MATERIALS. Page 22