IWCE Title Modern Spectrum Management Techniques for the Public Safety Professional VenueIWCE 2005 DateApril, National Public Safety Telecommunications Council Syracuse Research Corporation

IWCE This is the third year in a row that “Modern Techniques” has been presented. We are going to build upon our past sessions –More complex every year –This year less tutorial, more “What is Possible” This year: –Shortspacing to 700 MHz television: making the case for mobile and portable operations –4.9 GHz modeling techniques, with interference and performance prediction –Packing and mining – the ultimate techniques…. –Some “teasing” A quick note: Thanks to NYS and NPSTC for supporting much of the research behind the development of these techniques! Overview

IWCE PART I: Shortspacing to 700 MHz Television: Making the Case for Mobile and Portable Operations

IWCE Previous Studies have indicated that 700 MHz public safety channels might be available nearly everywhere –NYS, NPSTC, Guard Band Managers, etc –But would require a significant waiver process A roadmap to achieve these waivers was presented at the NPSTC meetings last Fall –Focus was on the New York City area –Overview of entire process with details on base station to TV interference NPSTC is developing guidelines that define all of this –Don’t get overwhelmed, there will be a how-to guide available from NPSTC documenting all this (and more) by mid-2005 Overview

IWCE These are complex waivers –Although some precedent exists, some concepts that will be utilized are “new” –The scale and location of these waivers can be massive (especially in areas with many TV stations) FCC Waivers

IWCE Stations Pertinent to 64/69 Operational Pairing

IWCE Stations Pertinent to 64/69 Operational Pairing – Primary Interference Sources to TV (2) Interference to TV reception by adj-channel PS towers within or near the grade B (3) Interference to TV reception by adj-channel PS mobile/portable units within or near the grade B (1) Interference to TV reception by co-channel PS towers near the grade B

IWCE Interference to Television, Case (3) Interference to TV reception by adjacent channel PS mobile and portable units within or near the grade B For a 64/69 pairing, need to ensure that WFUT TV-68 maintains a set D/U ratio within its service area. –Interferers are roaming mobile and portable units –No precedent on this, need to sell the FCC on this, balanced against needs of PS

IWCE Interference to Television, Case (3) For these cases we will need to compute the size of the interference “holes” around roaming public safety units –Interference range to TV reception from active mobile/portable units We will assume free space propagation from the mobile units, with 25 W ERP at 1.8 m AGL We will assume free space propagation from the portable units, with 0.32 W ERP at 1.6 m AGL

IWCE x Adj-Channel TV Station Grade-B FIGURES ARE NOT TO SCALE - EXAGERATED DIMENSIONS x Public Safety Mobile or Portable Unit d: “Hole Size” “d” is the free space loss distance required to reduce the Mobile/Portable ERP level to the TV signal level minus the required D/U protection level. It is a function of D (the desired TV signal level) and a variable protection level D/U (itself a function of frequency offset from the TV signal). Illustration of the ‘Hole” Concept

IWCE Mobile Interference Effects Clearly, mobile interference is a statistical phenomena –Random process with temporal, spatial, and frequency dependence Best way to capture its effects is to: –(1) Simulate the mobility of the operations –(2) Integrate the mobile interference effects against population distribution –(3) Perform Monte Carlo trials to determine the characteristics of the interference distributions

IWCE Mobile Interference Effects: Process Set Mobile Distribution Uniform or Correlated –Roads or Area Density –County or Region –Number of Units ERP –Mobile or Portable Frequency Offset Compute U Compute D-U Free Space Loss Mobile ERP Worst case, min FSPL to (x,y) Compute D Longley Rice 3-sec grid Compute population grid 3-sec From FCC data (DTV program) Compare to Required D-U Stanks look-up Function of offset,  f Function of D Compute Effects %Grade B j = j=j+1 j=1 DO UNTIL j=J Preprocessing

IWCE What is the D/U? DATA SOURCE: Receiver Susceptibility Measurements Relating to Interference Between UHF Television and Land Mobile Radio Services, FCC/OET TM 87-1, April The D/U ranges from -2 dB to – 43 dB, depending upon the desired signal strength (D), and the offset from the adjacent channel TV signal. The average is as follows: Public Safety 64/69 Pairing Adjacent Channel TV (63 and 68) Desired to Undesired Thresholds

IWCE Mobile Interference Effects – Receive Power Levels Receive Power (dBm) at 9.1 m AGL WFUT Grade B

IWCE D/U Requirement at  f = 9 MHz, From Stanks Tables dB Derived From: FCC/OET TM87-1, Receiver Susceptibility Measurements Relating to Interference Between UHF Television and Land Mobile radio Services project No. EEB-84-4, April 1986

IWCE Example: Interference from 10 Units/County NOTE: This free space interference is very conservative. A two-slope power law would reflect reality – and reduce the interference significantly

IWCE Example: D/U from 10 Units/County D/U (dB)

IWCE In this case: 0.06 % of Grade B Population Affected Example: Grade B “Holes” from 10 Units/County WFUT Grade B

IWCE Convergence of Initial Results

IWCE Total 110 Total 22 Total 55 Total In this case, the trend indicates that even in the worst case conditions, there would need to be over 350 simultaneously active mobile units per county, or over 3,800 total simultaneously active mobile units in operation before even 1% of the Grade B population is affected Trends: % Grade B Population Affected

IWCE PART II: 4.9 GHz Modeling Techniques: Interference and Performance Prediction

IWCE GHz Broadband Characteristics 4.9 GHz broadband coverage characteristics differ greatly from narrowband voice below 1 GHz –Typically Time Division Duplex (TDD) –Coverage is short range –Reflections and multipath both help and hinder performance –Packet data with lost data retransmitted, not continuous voice stream.

IWCE GHz Interference Scattering and Multipath

IWCE GHz Interference Coexistence of deployments can be complicated – even when the systems are shared! Scattering and Multipath Scattering and Multipath

IWCE Performance Scenario Generated by SRC/NSO for NPSTC Purpose was to show that COTS emmisions masks could support PS capacity requirements at an “extreme” incident scene, with no on-scene spectrum management required Multifaceted Simulation: –Complex incident, in a worst case environment –Extremely detailed coverage models –Service-specific traffic profiles –Use of type PHY –Use of mesh routing, with node retransmission overheads –Accounting of MAC overhead –Accounting of both RF and packet collisions –Retransmission of lost packets See the complete story on-line at NPSTC’s web site: –Under FCC Docket (August 19, 2004) –

IWCE Incident Area Chemical Storage Tanks Car Bombing Secondary Remote Detonated Explosive

IWCE Police Fire EMS Mobile Command Centers Explosion Scene Bomb Squad Robot and Control Triage Area

IWCE Police Fire EMS Bomb Squad POLICE Incident Routing and Information Flow

IWCE Received Level (dBm)

IWCE Received PHY Data Rate (Mbps) Packets

IWCE Simulation Results

IWCE Mobile Command Access Points Mesh Routing Points Reverse Link Video From Robot

IWCE PART III: Packing and Mining: The Ultimate Techniques….

IWCE “Frequency Mining” involves finding frequency resources at defined site locations –Defined process, based upon FCC rules and/or coordination guidelines –Repetitive and time consuming –Focus here is on automated processes “Frequency Packing” involves assigning frequencies system wide (or region wide) in some type of optimal fashion –System design process –Extremely complex optimization problem –Very time consuming –Focus here is on automated processes Mining and Packing

IWCE The processes themselves are quite simple, however an effective automated implementation can be very complex Data Needs: –Sites and site capacity targets, based upon system design –FCC license data –RPC allotment data Coverage Model for MLS, Reliability, and Reliability Degradation –In this example, Longley Rice with ITS 3-sec terrain and no LULC losses Defined Reliability Parameters –Ex. CPC f = 18 dB, IF ENBW = 12.5 kHz,  ln = 8 dB, NF = 10 dB Upon examination of results, a decision can be made at to which spectrum plan to use –Ultimately a trade off between coverage and capacity Mining and Assignment Process

IWCE Co/Adj Interference External Co/Adj Interference Internal Possible Assignments Use matrix “maps” in the optimization process Soft or hard constraints are applied (arrays can be “fuzzy” logic) Assignments Made General Assignment Methods Frequency

IWCE Pure Tile based Optimization (OUCH!) Depth corresponds to # of sites Height and width correspond to tile analyses Generating the input arrays is a large computational task! Integrating through the depth gives MLS and S/(  I+N)

IWCE Mining and Packing Process Reuse Step Over 1,200 fully linked html pages with integrated text and graphics FCC Data SWN Data DHAAT Results. 800 PS Pool Input Data Assignment Maps (Computed) All Available Freqs. Available Freqs. SWN Capacity Needs ASSIGN, NxF Binary Matrix Assignments NxF Matrix C, Nx1 Vector SWN_Data, Nx1 Structure FCC_Data, Mx1 Structure FREQS, Fx1 Vector Selections (Computed and Optimized) Documentation Reliability Degradation CO,NxN“Fuzzy” Logic Matrix FCC Data Site Data DHAAT Results. 800 PS Pool Input Data Assignment Maps (Computed) All Available Freqs. Available Freqs. Capacity Needs ASSIGN, NxF Binary Matrix Assignments NxF Matrix C, Nx1 Vector Site_Data, Nx1 Structure FCC_Data, Mx1 Structure FREQS, Fx1 Vector Selections (Computed and Optimized) Documentation Reliability Degradation CO,NxN“Fuzzy” Logic Matrix

IWCE Reliability Degradation? Q: What the heck is “Reliability Degradation”? A: It is a a reality-based measure of actual interference effects It is based upon TSB-88 concepts –Communications reliability –Tile based interference assessment –Equivalent interferer combination –Technology to technology ACCPR effects –Protection afforded only where service area exists, not over an entire IMAGINARY contour –Design to  S/(I+N), not simple contour intersections Maximizes reuse, while offering accurate interference assessments As an aside; think about this prior to rebanding. –Baseline your current reliability –Compare your post rebanding reliability before accepting the assignments. –Frequency coordinators do not go to this level of detail

IWCE Two Close Sites, 16-km Separation Example Interference Determination

IWCE Example Interference Determination Power Levels, Site 1

IWCE Example Interference Determination Power Levels (40 and 5 dBu), Site 1

IWCE Power Levels, Site 2 Example Interference Determination

IWCE Example Interference Determination Power Levels (40 and 5 dBu), Site 1

IWCE Example Interference Determination MLS Areas

IWCE Example Interference Determination MLS Power

IWCE Example Interference Determination Reliability Degradation Site 1 to Site 2

IWCE Example Interference Determination Reliability Degradation Site 2 to Site 1

IWCE Balancing Capacity with Coverage

IWCE Spectrum Engineering Example - Processing Scale of Inputs –>1,000 Sites –> 120,000 incumbent licensed site/channels –244 paired channel possibilities Three unique spectrum plans corresponding to Region 2, Region 7, and the Non-Border Region Mining and Packing Computations –A > 1,000 site MLS study –Approximately 200,000 individual tile based multi-site reliability studies –Examination of over 121 MILLION distance and DHAAT combinations Spectrum Plan Output Documentation –Auto generation of over 1,200 fully linked html pages with integrated text and high resolution graphics

IWCE The bottom line is time and money This automated process is: –Much more accurate than typical techniques –Much more efficient than typical techniques See below, and compare 2-3 weeks of labor (automated) to as much as 64 MAN-YEARS of labor to achieve the same thing (manual) –This allows us to handle new and larger problems –This is how repacking before rebanding can be achieved Time Savings

IWCE Contact For Further Information Sean O’Hara Business Area Manager Analysis, Communications and Collection Systems Syracuse Research Corporation, Systems Technology Center Vice Chair NPSTC Technology Committee Co-Chair NPSTC Broadband Working Group Co-Chair NPSTC Border Issues Working Group Vie-Chair Software Defined Radio Forum Spectrum Efficiency and Cognitive Radio Working Group (315)