National Public Safety Telecommunications Council RPC Training Session Tile Based Coordination of 700 MHz Public Safety Spectrum (with TSB-88 Concepts) Atlanta GA, November 12, 2007 Margaret Daly and Sean O’Hara NPSTC Technical Support Regions 8, 19, 28, 30 and 55 SRC - State of New York - SWN

Introduction Purpose Relevancy Audience Collaboration Introduce RPCs to techniques and requirements for handling detailed coordination and coexistence of diverse 700 MHz technologies Relevancy 700 MHz spectrum will be deployed for more flexible use, and with a greater variety of bandwidth configurations We have an immediate need to manage these issues Audience Technical System Operators, RPC Technical Committee Members, Frequency Coordinators, Spectrum and System Planners, etc Collaboration These concepts were developed in collaboration with many Regions

Need for Accurate Coordination at 700 MHz

700 MHz Coordination It is up to us (the RPCs) to manage the 700 MHz spectrum effectively If we do not… Interference will result Regional capacity will drop Deployment flexibility will go out the window The 700 MHz Pool was generated to maximize spectrum availability It assumes responsible deployment of this precious spectrum resource Its interference constraints must be followed The FCC gives us basic Rules – We can impose whatever else we need in order to manage the spectrum It has been given to us to manage

700 MHz Pool Allotments For nearly all of the US, all near term applications must be consistent with the CAPRAD pool allotments Each application must be consistent with the pool until the Region(s) decides otherwise Inter-regional coordination may be based upon these pool allotments for quite a while But these are not a replacement for communications or proper coordination

What Are the “Allotments”? Each County allotment: Is a contiguous 25-kHz Block, providing (4) 6.25 kHz channels, or (2) 12.5 kHz channels, or (1) 25-kHz channel Maintains at least 250 kHz separation with all other allotments within each county Each County (except PR/VI) received a minimum of five of these 25-kHz blocks The remainder were allotted according to the capacity model, and reuse constraints Maximum reuse for responsible utilization County size, terrain and US borders do affect availability

700 MHz Channel Allotment Pool Region 8 Area 700 MHz Channel Allotment Pool

Example of Reuse - NE United States, Channel Block 142 (On-Channel Allotments) The allotments were packed according to Rules that included: Service and Interference Contours that utilized terrain, political boundaries, and geographic separation constraints Modeled Capacity Needs

The Pool Assignments are PACKED Example: Block 52 NYC (NY), New Haven (CT), Burlington (NJ), Berks (PA) Co-Channel Blocks

Using Communications “Reliability” as a Metric

Coverage is a Complicated Concept Coverage is a random process Each location within the state is defined by a coverage “reliability”, which is a probability of achieving a particular level of performance at that location Coverage is interference limited Coverage reliability is dependent upon the reuse of spectrum resources Coverage is multi-dimensional Depends upon the entire collection of received signal, both desired and undesired Relationships are very complex Coverage changes as the system evolves Adding/changing sites, frequencies, etc Internal and external to any given system

How Can You Look at Coverage? Traditionally, we used contours 800 MHz NPSPAC: Okumura 40 dBu, 25 dBu, 5 dBu These gave us limited details regarding either coverage or interference Then, we used propagation models and tile studies But in most cases, these were still treated as contours We really need to look at Reliability Noise Limited Reliability Interference Limited Reliability Reliability Degradation from Noise Limited to Interference Limited How? What makes up “Reliability” What makes up an interfering condition

Contours and Tile Studies Closed polygons representing service areas and/or interference regions Various types are used Regulatory and regional planning System design (tile based) Tile Studies Most accurate way to manage the spectrum Used for Siting/System design, Coverage/Interference prediction, reliability estimation, Spectrum reuse planning Various models are available Many commercial packages But few standardized algorithms Complex and time consuming when large systems are involved.

Multiple Site C/N No Interference (Noise-Only)

Multiple Site C/(N+I) Note the Loss in Reliability and Coverage Interference

Tile/Propagation Analysis GOAL: ESTIMATE COMMUNICATIONS RELIABILITY Performance in the presence of fading, noise and interference Voice quality, data rate, etc Fading usually wrapped into Channel Performance Criterion (CPCf) Reliability is mainly dependent on: CPCf (a technology and QoS-dependent faded S/(I+N) metric) Overall receiver system noise floor Received desired power and interference power Local variance of each of the desired signal and interference sources Reliability is a direct function of margin over CPC Margin = S/(I+N)attained - S/(I+N)required

Tile by-Tile Evaluation Reliability Margin: Tile by-Tile Evaluation Level (dBm) -95 Desired Note: Antenna adjustments (i.e. portable and sometimes building loss) lower both the desired and undesired signal, leaving S/I unchanged Interference can be be co-channel, and/or near or far adjacent. If adjacent then ACCPR must be computed The DESIRED and the INTERFERING signals are either modeled or measured Antenna Loss -115 -105 Faded CPC Criterion -120 N+I Margin Noise Margin I+N Interference Or Site Noise -125 Receiver Floor, N Receiver NF -135 kTB (ENBW)

Aggregate Coverage Example As previously stated, coverage is a complex concept. Lets look at small set of “coverage” tiles to see how this all comes together. Lets take one tile as an example…

Example: Talk Out Coverage Each tile is served by multiple sites on multiple frequencies – each with a different reliability for mobile and portable operations. F4’ F4 F1 F3’ F1’ The overall tile reliability depends upon all of the individual reliabilities As determined through Monte Carlo analyses (via TSB-88 methods) F1’ F3 F2 F2’ Desired Signals Undesired Signals

Coverage Discretization This output grid gives a continuous gradient of system coverage reliability Notice that the coverage is NOT “Black and White”

Coverage Discretization This “black and white” point is important when we look at a tiled reliability output against a critical resource location

Coverage Discretization A discrete “black and white” analysis could show how many tiles intersecting the critical area have less than some set degree of coverage E.g. 29 total area units in critical location 4 tiles at less than 95% reliability 86% of the critical location at sufficient coverage levels

Coverage Discretization A continuous analysis could show the overall reliability of tiles of the coverage of the critical location E.g. 29 total area units in critical location Average tile reliability of 93%

What is an Interference Condition? TSB-88 defines a reduction in reliability How much of a reduction is unacceptable? Subjective, 1%? 2%? 10%? What is the protected “Service Area” (PSA) of an incumbent or applicant? 40 dBu Contour Jurisdictional Area Set of tiles with some defined reliability (e.g. > 65%) everywhere, or only within PSA? Again, subjective What interferers should be considered when evaluating Reliability Degradation? All (cumulative interference)? Most accurate, and most time consuming Only the current application? Fastest and least accurate, is we are doing at 800 MHz Seem complex? Yes

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

Consistency and Stability of Reliability Degradation Example: Compare RD impacts between 1500 radio transmitter sites using two different models: Longley Rice v1.2.2 and RAPTR

Consistency and Stability of Reliability Degradation For Adjacent channel 99.3% of points with RD difference < 0.1% 99.5% of points with RD difference < 1% 99.9% of points with RD difference < 10% For Co channel 96.0% of points with RD difference < 0.1% 97.3% of points with RD difference < 1% 99.3% of points with RD difference < 10% Conclusion, two very different propagation models give nearly identical results when RD is employed Normal contours and/or propagation modeling gives widely varying results

Measures of Reliability Degradation Reliability degradation can be measured in at least two ways Percent Reliability Degradation (PRD): Average reduction in reliability over a service area Over a service area, compute the average of the difference between the noise and interference limited tile reliabilities Area Reliability Degradation (ARD): Average reduction in service area meeting a set Reliability threshold Over a service area, compute the ratio of the difference in interference and noise limited area served at a particular reliability level

Technology and Adjacent Channel Effects

Size (and Technology) Matters We have a lot more technology options at 700 MHz than we have been used to in the past Bandwidth configurations that can support many combinations of TDMA and FDMA Each specific technology has a specific CPCf and receiver IF filter model associated with it There are also the same types of system design choices that we had at 800 MHz High sites and/or low sites Portable and/or mobile designs Simulcast and multicast designs These all have an impact on coordination

Technology and Design Considerations Example 1 ~1200 mi2 18-25 kHz Channel Pool High Site Design 5 Sites 8 mi Multicast: 7-12.5’s / site 14-6.25’s / site (TDMA or FDMA) No Reuse 5 mi Single Zone Simulcast, 18-25’s / site Two Zone Simulcast, 18-12.5’s / site

Technology and Design Considerations Example 1 18-25 Channel Pool Low Site Design 22 Sites, 7 Cell Cluster ~18 dB C/I ~1200 mi2 3 System Simulcast: 12-12.5 per Site Multicast: 5-12.5 per site 10-6.25 per site (TDMA or FDMA) 3.7 mi

Technology Considerations -Power Spectrum: Adjacent Channel Coupled Power -50 ACCPR = -64.5882 dB -100 Power Gain and Normalized Interference PSD, Resolution BW: 0.0313 kHz -150 -200 -250 Interferer PSD, C4FM Victim IF Filter, Root Raised Cosine Intercepted Power Integrated Power Original Offset: 12.5 kHz Offset w/Frequency Drift: 11.6979 kHz -300 -60 -40 -20 20 40 60 Frequency

Adjacent Channel Coupled Power (12.5 kHz example P25 Phase I Transmitter) - 50 40 30 20 10 150 125 100 75 25 Frequency Power Gain and Normalized Interference PSD, Resolution BW: 0.031 3 kHz ACCPR = 71 dB Interferer PSD, C4FM Victim IF Filter, Root Raised Cosine Intercepted Power Integrated Power 21 dB 39 dB Victim IF Filter, Butterworth P25 to “Wide” ~20 dB P25 to P25 >65 dB P25 to FM ~40 dB

Transmitter Characteristics of Other Technologies iDen SAM EDACS WIDEBAND TETRA CQPSK Analog (2.5 kHz)

Adjacent Channel Coordination at 700 MHz 40 dBu Service Nearly all 700 MHz Narrowband technologies provide better than 60 dB of adjacent channel protection In context of the old contours methods, this means that to 40 dBu service and 65 dBu interference contours cannot overlap In the tile analyses, you will de-rate the interferer by the ACCPR, then treat as co-channel 65 dBu Interference

Guidelines and Helpful Hints Get all the information you need from applicants System type Technology (CPC and IF Model) See Region 8/30/55 plan for defaults Service Area Boundary (usually political boundary) Antenna Pattern(s) Adjacent Channel Considerations You really only need to do detailed ACCPR analyses when service areas overlap and channel offsets are less than 25-kHz Otherwise just examine co-channel impacts ACCPR Computations Use tables or Excel Tool from TSB-88 Other options are available as well Simulcast Systems Victim: Treat simulcast systems as a single site. Interferer: Treat as individual interferers

Tile-Based Coordination Approach (Region 8, 30, 55)

General Region 8/30/55 Application Process

What Has Regions 8/30/55 Settled On? (Propagation/Reliability Modeling) All analysis is tile based and will use the Longley-Rice model in median (50,50,50) mode Need the accuracy so that interference can be carefully modeled Need the accuracy so that frequency reuse is reasonable 50 dBµ levels must be 80% contained within the service area Jurisdictional area plus 8-km Similar to the old 40 dBµ contour rule Necessary for responsible radiation control

ARD is compared to noise limited What Has Regions 8/30/55 Settled On? (Propagation/Reliability Modeling) The metric chosen for reliability reduction due to co and adjacent channel use is called Area Reliability Degradation or ARD See next slide The selected ARD thresholds are different for in-pool and out-of-pool applications For in-pool, 2.5% ARD per applicant, up to 5% ARD total and cumulative For out-of-pool, 0% ARD is compared to noise limited Means less “state-tracking” is required

What is ARD Again? ARD is a reduction in area reliability caused by co and adjacent channel operations First, an incumbents reliable noise-limited coverage area is determined using 3-second propagation analyses Example, noise limited service area for an incumbent may be found to be 100-km2 This represents the total area within their service area that falls at 90% reliability levels as determined by TSB-88 Next, an applicants proposed operations are used to model the reliable interference-limited coverage area of the incumbent, again using 3-second propagation analyses Example, interference limited service area for the incumbent may be found to be 98-km2 This gives an ARD of 100*(1-98/100) or 2%

What Does a Region 8/30/55 Application Contain? In order to do this complex processing, there is more information required from an applicant than there was at 800 MHz We have dedicated application forms that must be filled out completely Detailed horizontal and vertical antenna pattern sheets Detailed Jurisdictional Area Boundary file, with buffer included ARD analysis must be provided by applicant, and WILL BE VERIFIED by the Regions

Some Available Tools NYS-SWN has developed Matlab tools for performing the ARD evaluations They are applying some serious spectrum engineering horsepower in the SWN deployment… They will be compiling these tools into an easy to use stand alone software package for free distribution to the RPCs Government developed, with NYS-OFT Copyright Installation/exe, all files, including terrain Availability: In the next couple months ONLY for RPC Application EVALUATION Looking to see if other RPCs would like this Again, would be made available for free

Available Tools Application (ebf/601) boundary.xls antenna.xls Input RPC or CAPRAD Timelines/Apps ULS/FCC Output Word Report(s) html Report(s) emails Terrain (3-sec) Pool Assignments Resident Data Output reports include fully formatted text, tables, and graphics (propagation maps, interference areas, etc) User only has to select the application file(s)

Demonstration NYS-SWN Software Beta for Application Evaluation FCC 700 MHz Regions 8, 30, and 55

Q&A and Feedback

Q&A and Feedback This is a lot to pack into 75-minutes Margaret or I will be happy to go these concepts this again at area RPC meetings Usually attend Region 8, 30, 55 meetings Often attend Region 19 and 28 meetings as well Any Questions? Any Feedback?

Contact for Further Information Sean O’Hara Business Area Manager – Analysis, Communications, and Collection Systems Syracuse Research Corporation ohara@syrres.com 315.452.8152 office Margaret Daly Research and Communications Engineer Syracuse Research Corporation mdaly@syrres.com 315.452.8409 office