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Modeling Incident Scenarios on the PS Broadband Network March 26, 2014. John Facella, P.E., C.Eng. Senior VP, RCC Consultants. Agenda. User Needs Assessments Capacity is Different from Coverage Summary. User Needs Assessments - not Easy. Law, Fire EMS use data differently
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Modeling Incident Scenarios on the PS Broadband NetworkMarch 26, 2014 John Facella, P.E., C.Eng. Senior VP, RCC Consultants
Agenda • User Needs Assessments • Capacity is Different from Coverage • Summary
User Needs Assessments - not Easy • Law, Fire EMS use data differently • For decades Law has been a consistent user of data: NICIC lookups, field records, CAD silent dispatch, etc. • Fire & EMS have not used data much in the past, but that is changing (e.g. EPCRs) • NPSTC and PSAC have put together a 30 page list of applications that might be used by each service • Many PS users have difficulty in imagining future uses of data as opposed to current
Identifying Future Uses of Data can be Hard… “Sonny, how can I tell you how often I’ll use the new superhighway? I don’t know what a superhighway is!” Photo: www.ar15.com
Some Example Data Uses by Service • Law • Real time video from commercial bldgs • Arrest process check list • AFIS Fingerprint scanner • Airborne platform video sharing • Officer cam • ALPR • Fire • Personnel accountability • Vehicle extrication info based on license plate • GIS info for wildland fires • Wildland personnel tracking • In-building personnel tracking • EMS • ePCR from CAD to EMT to hospital • Geo based illness or pandemic info • 2 way video hospital –scene • 12 lead + O2 sat + EtCO2 • ‘Just in Time’ video refresher enroute
Dimensioning the App Usage Profile • Numbers of responders, locations • Numbers of mobile, portable, and vehicular modem wireless devices • Current apps in use, by responder type & incident type • Expected future apps, by responder type & incident type • GIS geo-overlay of incident history • Multiple other factors • Create probabilistic data demand by location, time of day, etc.
Needs Assessment:On-Line or Desktop Application 2. Add Wireless Data Apps 3. Add Usage Patterns, Number of Users by Department Expected Data Rates and Latencies 1. Begin Survey
Agenda • User Needs Assessments • Capacity is Different from Coverage • Summary
Capacity vs. Coverage • For FirstNet to succeed, it has to provide PS what cellular carriers cannot do today: improvements in coverage, capacity, reliability, security, & local control • Most of the industry discussion has been about coverage • Capacity is equally important, even in rural areas • Examples: 9/11 Shanksville PA; Horrific PA Amish school house massacre • Although rural areas may have less responders; as a result incident commanders may therefore be more dependenton multiple video feeds • Designing for coverage Designing for Capacity
Issues Impacting “Delivered Capacity” • “Delivered Capacity” is bandwidth that a PS user has available at her location. It is affected by: • User location to cell center (LTE ‘gear shifts’ data speed between 64QAM, 16 QAM, and QPSK) • User location to adjacent cell (interference) • Antenna sectorization • MIMO use • User’s prioritization • User’s app bandwidth and prioritization • App’s FEC and jitter, latency, packet loss sensitivities • Nature of user’s traffic, and adjacent users’ traffic: bursty, variable rate, continuous, random (stochastic) • Adjacent users in same sector and their apps/priorities • Total cell site backhaul capacity vs. total bandwidth demands from all sectors of that cell
Issues Impacting “Delivered Capacity” • Sidebar - Operational Implications: • Delivered capacity to a particular user will change over time depending on the changes to the factors in the previous slide • Completely different experience from voice trunking • For example this will result in inexplicable changes to video quality during an incident • Depending on the incident’s needs, It may be necessary to make on-the-fly changes to user and application priorities in real time Photo: monkeymucker.blogspot.com
Issues Impacting “Delivered Capacity” • LTE assigns Resource Blocks to users, and reserves some for channel signaling • LTE systems reuse the same frequency blocks at every cell site, so adjacent cell sites can interfere with each other and reduce capacity • How much capacity is needed for a single UL video feed? • 0.2 Mbps to 6.1 Mbps depending on codec, frame rate, subject movement speed, lighting, video usage (situational awareness vs. evidential) • But capacity (in megabits/second) falls off rapidly away from the center of the cell
Data Capacity vs. Distance to Cell Site 12 Video Feeds (1 Mbps each) At 2 KM (1.3 mi) away Yet multiple authors suggest that even common incidents will require from 4.8 to 6.3 Mbps total UL Data speed! Data speed Mbps Only One Video Feed At 10 KM (6.5 mi) away 0 1 2 4 6 8 10 12 KM • From Tait presentation at • 2013 Radio Club of America • Tech Symposium
Issues Impacting “Delivered Capacity” • Multiple authors have shown that incidents may require large amounts of bandwidth – up to 6.3 Mbps UL • Andy Seybold’s Cornerstone project in 2011*: • Barricaded Hostage: peak 6.3 Mbps UL; peak 19.2 Mbps DL • Bomb incident: peak 4.4 Mbps UL; peak 13.5 Mbps DL • Tait** Traffic Accident Scenario: 4.8 Mbps UL • Designing a system that delivers at least 6.3 Mbps will require more sites than just providing coverage with minimal capacity • However as sites get closer together, interference from nearby cells begins to become an increasing factor • Bringing in deployable cell sites into an incident creates additional variables • LTE networks in future will be self-optimizing * www.andyseybold.com ** 2013 Radio Club of America Tech Symposium
Example Sectorized LTE Coverage & Traffic at Aggregation Site Coverage Requirements • Coverage to a PC-Mounted USB device or handheld device for 95% area coverage with 95% reliability with the following in-building requirements: • 6 dB statewide, • 10 dB in the cities of Milford and Georgetown, and • 18 dB in the cities of Dover, Wilmington, Newark and Rehoboth.
Agenda • User Needs Assessments • Capacity is Different from Coverage • Summary
Summary • User data needs not easy to survey • Future data needs even harder • PS LTE systems must deliver both coverage and capacity • Designing for capacity is different • Software tools are available to do this • A single incident may need peak UL speeds of 6.3 Mbps • “Delivered Capacity” to a user dependent on multiple factors • Data speeds to a user will vary over time