IEEE 1900 5 Contribution Authors Name Affiliation Address

IEEE 1900. 5 Contribution Author’s Name Affiliation Address Mc. Lean, VA Phone 703 -983 -6281 email John Stine MITRE Corporation jstine@mitre. org Document Title: Document Date: Document No: Spectrum Consumption Modeling Tutorial 16 July, 2014 5 -14 -0052 -02 -subs (assigned by document server https: //mentor. ieee. org/1900. 5/documents) Notice: This document has been prepared to assist IEEE Dy. SPAN-SC and its Working Groups. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in 6 form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE Dy. SPAN-SC. Patent Policy and Procedures: The contributor is familiar with the IEEE Patent Policy and Procedures including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard. " Early disclosure to IEEE Dy. SPAN-SC and its Working Groups of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair <matthew. sherman@baesystems. com> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE Dy. SPAN-SC Committee. If you have questions, contact the IEEE Patent Committee Administrator at < patcom@ieee. org >. 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 1

Purpose • This document introduces and provides an overview of a proposed approach to model the consumption of spectrum by RF devices and systems 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 2

Spectrum Consumption Modeling Objectives • Provide means to capture all the relevant parameters and phenomena that affect spectrum consumption • Provide means to compute compatibility between any two models without dependence on external databases of environmental or system data • Support methods for computing compatibility that are tractable and definitive 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 3

The Role of Spectrum Consumption Models SCMs are designed to serve as a loose coupler for the spectrum management enterprise 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 4

Proposal has 12 Constructs • • • Captures the spectral content of the signal and the unique characteristics of spread spectrum systems Total power Spectrum mask Captures a definition of interference Underlay mask Can capture antenna effects Power map Can capture environmental effects Propagation map Intermodulation masks Captures susceptibility to Platform intermodulation Location Enable greater resolution in Start time spectrum management End time Minimum power spectral flux density Can capture behaviors that Protocol or policy enable compatible reuse Most constructs have probability data elements to declare confidence in parts that are variable or are uncertain 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 5

Combining Constructs into Models Constructs are used to model transmitters and receivers There is an XML schema for model construction 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 6

Model and Collection Functions • System Model – Consists of transmitter and receiver models that are part of a system • Collective Consumption Listing – Lists uses of spectrum by systems, transmitters and receivers – Heading identifies the time, space, and frequencies over which the list is complete • Spectrum Authorization Listing – List of system, transmitter, and receiver models identify spectrum boundaries within which use is authorized • Spectrum Constraint Listing – List of system, transmitter, and receiver models identify existing uses of spectrum that have precedence with which new uses must be compatible 6/15/2021 Doc #: 5 -14 -0052 -02 -subs Heading identifies the limits in time, space, and frequencies over which the list applies 7

Combining SCMML with Process Data • SCMML only intends to capture spectrum use boundaries (necessary to be a loose coupler) • Most SM documents will use combinations of schemata • Complementary schemata functions – Cataloging models (e. g. modeler identity, version, date, …) – Database control (e. g. regulatory administration, user ID, database ID, …) – Enterprise management (e. g. manager ID, user organization, …) – Negotiating service level agreements (e. g. party ID, price, probability of interference, enforcement data, remediation data, …) – Markets (e. g. price, bid, signatures, …) – RF device policy (e. g. device ID, security codes, …) • Complementary data does not need to cross domains 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 8

What is included in the specification • Overarching XML schema that defines the model “Spectrum Consumption Modeling Markup Language” (SCMML) – Data types for the fundamental data elements required within each construct – Explicit data types for each construct – Transmitter, receiver, and system data types – A collection data type for collections of transmitters, receivers, and system models • Explanations – What each construct captures – How constructs work collectively to represent use boundaries – Methods and algorithms for computing compatibility between uses 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 9

What models must convey • The extent of RF emissions – i. e. the power spectral flux density of RF emissions anywhere with respect to a user • A definition of what is interference – i. e. what emissions from another user would be considered harmful • Time and location of use • If known, behaviors and features that enable sharing 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 10

How models are built • Modeling from scratch requires: – Extensive knowledge of the system being modeled • What does it emit • What interference is harmful • Understanding of the operational use of the system – Environmental data and propagation models • Modeling will likely be supported by tools that capture the environment, propagation effects, and the unique features of the RF devices, e. g. antennas directivity • SCM are an abstraction that do not require the detailed data and computations that are part of the tools 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 11

DETERMINING COMPATIBILITY 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 12

Types of Spectrum Consumption • Transmitter – attenuation from the transmitter Reveals the extent of RF emissions Total power, propagation maps and power maps have opposite meanings • Receiver – attenuation toward the receiver Reveals what is harmful interference Spectrum can be consumed without any emissions 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 13

Compatibility Computations • Constructs are a means to specify the factors that determine a link budget • Modelers build SCMs to identify the power spectral flux density of transmissions and allowed interference • Assessment of compatibility determines if the interaction of the spectrum mask of the transmitted signal is compatible with the underlay mask of the receiver 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 14

A Link Budget Perspective – TPrcvr – Total Power in the receiver model – TPtmtr – Total power in the transmitter model – AGtmtr – Antenna gain from the transmitter power map – AGrcvr – Antenna gain from the receiver power map – PL(d) – Pathloss as a function of distance using a propagation map model 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 15

General Process for Computing Compatibility • Determine if uses will overlap in time and spectrum • Determine the constraining points (the point of primary operation and the point of secondary operation that most restrict the secondary user) • Compute the allowed transmit power of the secondary Constraining secondary transmitter Constraining primary receiver Secondary mobile user Primary broadcast user 6/15/2021 Doc #: 5 -14 -0052 -02 -subs The variety of means to specify locations and the use of directional antennas make the determination of constraining points the most challenging part of computing compatibility 16

FUNDAMENTAL DATA TYPES 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 17

Fundamental data types • Data types for commonly used variables: e. g. frequency, bandwidth, power, time, location, and direction • Unique data types for special SCM data structures: e. g. masks and maps • These are explicitly described in Chapter 5 of 1900. 5 -13 -0043 -02 -drft 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 18

Probability data type • Used in many of the modeling constructs and are associated with particular aspects of the constructs • Data type tries to clarify what probability means in the model – Approach: cumulative versus alternative 0. 8 Cumulative 1. 0 0. 2 Alternative – Nature: fleeting versus persistent • For the fleeting nature, the probability refers to the fraction of time in a state and being in any state is momentary • For the persistent nature, the probability refers to the likelihood of arriving at a state and being in that state may persist – Derivation: judgment versus estimated versus measured • By default all alternatives are used in computing compatibility • Consideration of probability requires peer-wise agreement on the method • Probabilities of different construct types are considered independent 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 19

THE SCM CONSTRUCTS 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 20

1 - Total Power A reference value to which other model constructs refer 20 d. Bm • Usually represents the value of the power driving an antenna at a transmitter and the allowed interference power after the antenna at a receiver • Other constructs affect the power so there is flexibility to obfuscate specific system capabilities • The probability element supports identifying a power distribution for systems that adapt their power or the specification of the probabilities of a collection of alternative discrete power levels 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 21

2 – Spectrum Mask A list of inflection points that form a mask. Each point consists of a frequency and relative power. A resolution bandwidth conveys the spectral density of the power terms, i. e. d. B/BW. Specifies the powerdensity spectrum of a signal (399. 925, -140, 399. 95, -100, 399. 975, -38, 400. 025, -38, 400. 05, -100, 400. 075, -140) Actual BW = 10 k. Hz frequencies: Relative frequencies: 6/15/2021 (-0. 075, -140, -0. 05, -100, -0. 025, -38, 0. 05, -100, 0. 075, -140) f = 400 MHz, BW = 10 k. Hz Doc #: 5 -14 -0052 -02 -subs 22

Spectrum Masks – Continued - 2 • A spectrum mask conveys the spectral content of a signal • Data Structure – The basic mask is a (1 n) array of real values alternating between frequency and power – Resolution bandwidth is a real value and applies to all power terms in a mask – Two versions • Continuous signal – the mask stands alone, frequencies are actual • Frequency hopped and pulsed signal – the mask is accompanied by additional values, frequencies are relative to a center frequency – A center frequency list or a list of frequency bands, where the pair identify the beginning and ending frequencies of a frequency band – A dwell time – A revisit period 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 23

Spectrum Masks – Continued - 3 • Probabilities may be associated with masks – Alternative – One or the other of a set of masks applies, e. g. radar scanning versus radar tracking – Cumulative – Multiple masks where those with higher probabilities subsume those of lower probability, e. g. systems that may adapt the bandwidth of their transmissions • When probabilities are used, there are multiple masks 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 24

3 – Underlay Masks (396, -90, 397, -110, 403, -110, 404, -90) BW = 10 k. Hz A list of inflection points that form a mask. Each point consists of a frequency and relative power. A resolution bandwidth conveys the spectral density of the power terms. Specifies limit to the allowed interference by frequency Together with the spectrum mask specifies the protection margin 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 25

Underlay Mask – Continued - 2 • Underlay masks may be one of two types – Relative to the spectrum mask and so also dependent on propagation – Constant over the location of the model so only dependent on the total power and the relative power density of the power map • Before evaluation for compatibility, spectrum mask and underlay mask power spectral density terms must have the same bandwidth reference • There are two methods for computing the power margin that results from the interaction of an underlay mask and an interfering signal’s spectrum mask – Total power – Maximum power density 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 26

Underlay Mask – Continued - 3 • Total power method of computing power margin uses the underlay mask as an inverted filter that reduces the amount of the interfering signal’s energy signal that interferes Energy beneath the underlay mask is subtracted from the energy under the spectrum mask 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 27

Underlay Mask – Continued - 4 • Computing the power margin using total power method has four steps 1. Determine the allowed interference the underlay permits 2. Adjust the shape of the interfering spectrum mask based on the shape of the receiver underlay mask 3. Compute the total power in the reshaped spectrum mask 4. Find the difference between the total power of the reshaped spectrum mask and the allowed interference specified by the underlay mask • There is a closed form solution for steps 1 and 3 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 28

Underlay Mask – Continued - 5 1. Determine the allowed interference the underlay permits Defined as the power beneath the lower 3 d. B bandwidth 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 29

Underlay Mask – Continued - 6 2. Adjust the shape of the interfering spectrum mask based on the shape of the receiver underlay mask Reshaped mask Underlay mask Spectrum mask 6/15/2021 Mask extends the full bandwidth of the underlay Doc #: 5 -14 -0052 -02 -subs 30

Underlay Mask – Continued - 7 3. Compute the total power in the reshaped spectrum Given two consecutive inflection points, mask and , , the equation for the line is where and. . The total power under the segment is determined in the linear scale and so within the segment between and , is and where 6/15/2021 Doc #: 5 -14 -0052 -02 -subs . For segments where , , and , , , . 31

Underlay Mask – Continued - 8 4. Find the difference between the total power of the reshaped spectrum mask and the allowed interference specified by the underlay mask - PMMask = 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 32

Underlay Mask – Continued - 9 Criteria for compatibility with underlay mask using the maximum power density method of power margin computation This spectrum mask violates the boundary of the underlay mask Compatible transmission • Maximum power density method of computing power margin – Determine the adjustment of the spectrum mask to ensure its power levels are beneath the underlay mask 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 33

Underlay Mask - 10 • Variants of the underlay mask allow identifying differences in robustness to interference based on bandwidth, frequency hopping, and duty cycle of interfering signals • In compatibility computations the spectrum masks are mapped to the least restrictive underlay mask for which they meet the criteria of use 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 34

Accounting for Signal Spaces • Used with underlay masks designed for the maximum power spectral density method of computing compatibility • Provide separate masks for different narrowband signal spaces – A signal space is defined as the bandwidth of a signal at 20 d. B below its maximum amplitude (This is arbitrary and could be something else. 3 d. B did not seem appropriate. ) – Independent masks are made for each signal space or a single mask is used with a list of adjustments of the form (BW 0, p 0, BW 1, p 1, …, BWx, px) 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 35

Determining Bandwidth • Bandwidth at -20 d. B from the maximum power 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 36

Signal Space Example • What combinations of interfering signals are tolerable? 6/15/2021 Doc #: 5 -14 -0052 -02 -subs Signal BW (k. Hz) PSD (d. BM /Hz) A 25 -93 B 100 -105 C 150 -101 D 25 -88 E 150 -87 F 100 -104 37

Determining Effective Bandwidth and PSD • Effective bandwidth is the sum of the bandwidths • Effective maximum power spectral density (EPD) is a normalized power spectral density of the collection of signals (assumes the same resolution bandwidth) • If both the effective bandwidth and the EPD are less than the limits of a bandwidth rated mask then the collections of interfering signals is compliant • Otherwise adjust to the bandwidth of the next highest bandwidth underlay – Spread the power spectral density to the bandwidth of the mask that is being used 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 38

Results for the Example Using a mask designed for the total power method of mask interaction is usually a better choice for indicating narrowband signal tolerance 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 39

Accounting for Frequency Hopping • Used with either method of computing mask interaction • Provide separate masks for different bandwidth time products (BTP) – A BTP is the product of the average amount of time a signal exists in the band of the mask and the bandwidth of the particular signal – A single mask is used with a list BTP vs power adjustment of the form ((BW T)0, p 0, (BW T)1, p 1, ---(BW T)x, px) 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 40

Frequency Hopping Example Two frequency hopping systems System 1 System 2 Spectrum mask: (-0. 0125, -20, -0. 0075, 0, 0. 00750, 0, 0. 0125, - Frequency list: ( 190. 0, 190. 025, 190. 050, , 194. 975) (i. e. Frequency band list: (190. 0, 193. 5, 196. 5, 205. 5, 211. 0, 218. 5) Dwell time: 200 sec Revisit time: 1. 0 msec 20) signals spaced every 25 k. Hz starting at 190 MHz and ending at 194. 975 MHz) Dwell time: 100 sec Revisit time: 20 msec Frequency hop power levels at a BTP rated receiver Channel Definition 20) Band Definition BTP from System 1 BTP from System 2 Since the combined BTP of the two systems, 1375 Hz sec, which is less than the 1, 500 Hz sec mask and the power level of both frequency hop systems is less than the power rating of that mask the use of both is compatible 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 41

Accounting for Duty Cycle • Used with either method of computing mask interaction • Provide separate masks for different interference duty cycles – A duty cycle is the fraction of time a signal is turned-on, on average – Each mask is qualified by a duty cycle and the maximum dwell time when the signal is being transmitted 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 42

Probability with Underlay Masks • Underlay masks may be defined with a cumulative approach and a fleeting nature • This allows consideration of all variations of constructs qualified with fleeting nature probabilities 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 43

Protocol and Policy Indexing • Provides a means to account for behaviors that allow spectrum sharing • A specific underlay mask is associated with a particular protocol or policy definition – Meaning: a coexisting system that uses the specified protocol or policy may use the associated mask for the assessment of compatibility 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 44

Selecting the Underlay Mask • A model of a receiver may use multiple underlay masks • As described there are criteria that must be met in order to use a particular map • In assessing compatibility, use the map that is least restrictive for which the criteria is met 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 45

Map Preliminaries • Coordinate systems – Earth centric – Earth surface – Platform • Rotation matrices • Coordinate conversions • Map data structures 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 46

Earth Centric Coordinates • The earth is shaped as an ellipsoid – Multiple ellipsoid datums exist that best represent the Earth’s surface at different geographic locations – We use the same ellipsoid used by GPS, the WGS-84 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 47

Earth’s Surface Coordinates • The x axis points to the north axis of the earths rotation, the y axis points east, and the z axis points toward the center of the earth Orientation with respect to earth centric coordinates changes by location 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 48

Platform Coordinates • x axis points in the direction of travel and the z axis points in the direction that is typically toward the center of the earth y x z 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 49

Rotation Matrices • Rotations follow the right hand rule – Rotations about the x axis moves the y axis toward the z axis – Rotations about the y axis moves the z axis toward the x axis – Rotations about the z axis moves the x axis toward the y axis 6/15/2021 Slide Doc #: 5 -14 -0052 -02 -subs 50 John A. 50

Earth to Surface Rotations Rotation about the y 1 axis Rotation about z 1 Rotation about y 2 • Converts a coordinate system from earth centric coordinates to one on the earth’s surface • The inverse rotation 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 51

Other Rotations • Between Earth’s surface and travel direction • Between travel direction and platform coordinates • Between power map coordinates and platform coordinates 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 52

Coordinate Conversions • Converting coordinates between earth and surface coordinates involves a translation to the new origin and then a rotation • The inverse 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 53

The Map Data Structure - 1 A method to assign values to a solid angle (0 , n 0, 0, 1, n 0, 1, 0, 2, …, 360 1, 0 , n 1, 0, 1, 1, n 1, 1, 2, …, 360 , 2, 0 , n 2, 0, …, nlast, 360 , 180 ) Sector Annulus n 1, 1 is the value associated with the solid angle that extends from elevation 1 to 2 and from azimuth 1, 1 to 1, 2 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 54

The Map Data Structure – 2 Reduce the map size by eliminating the obvious information (0 , n 0, 0, 1, n 0, 1, 0, 2, …, 360 1, 0 , n 1, 0, 1, 1, n 1, 1, 2, …, 360 , 2, 0 , n 2, 0, …, nlast, 360 , 180 ) Always begin with 0 , 0 combination, The 0 azimuth always follows the 360 – elevation combination Remove the leading 0 , 0 combination Remove the 0 that follows elevations The map always ends with the 360 , 180 combination Use 0 to mean the 360 , 180 combination (n 0, 0, 1, n 0, 1, 0, 2, …, 360 1, n 1, 0, 1, 1, n 1, 1, 2, …, 360 , 2, n 2, 0, …, nlast, 0 ) Maps can provide as much resolution as necessary where necessary 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 55

Example Maps (0, 0) (5 , 125, 0, 155, -10, 270, 5, 360, 100, 2, 0) (-5, 360, 80, 3, 360, 100, -5, 0) 6/15/2021 (-10 , 360, 90, -10, 150, 5, 165, -10, -360, 105, -10, 0) Doc #: 5 -14 -0052 -02 -subs 56

4 – Power Map A variable length n x 1 array that assigns power levels to solid angles about a point Specifies the relative power density by direction 20 d. B/m 2 (-20, 70, -25, 120, -30, 160, -35, 360, 150, -35, 0) 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 57

Power Map – Continued - 2 or Power + • Provides a directional gain • Together with the total power and spectrum mask (or underlay mask), specifies the power spectral flux density in a direction = power spectral flux density • The direction power spectral flux density is used as the 1 -meter power in the linear and piecewise linear log distance pathloss model (Part of a farfield model) • Power maps may include phenomenology in addition to antenna gain (e. g. insertion loss, environmental effects, …) 6/15/2021 Doc #: 5 -14 -0052 -02 -subs + 58

Power Map – Continued - 3 • Usually, the coordinate system of the power map is the same as the coordinate system of the propagation map • Exceptions – When referenced to a platform, rotation may be specified by the angles < , , > y x z – Direction may be fixed toward a point (antenna steers as the platform moves always pointing in the direction of the specified point) – Concentric maps used to specify scanning of directional beams, the outer map indicates the scanning region and the inner map defines the directional beam that is scanned 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 59

Hierarchical Power Map • Scanning region specified by one power map – Logical true value in the direction of scanning – Logical false in the directions not scanned • Antenna pattern specified by the second map True False This beam may be point anywhere in these directions 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 60

5 – Propagation Map A variable length n x 1 array that assigns parameters of a pathloss model to solid angles about a point. There are two models, linear and piecewise linear on a d. B to log distance (2, 40, 2. 07, 130, 2. 13, 230, 2, 0) Specifies the rate of attenuation by direction (2, 550, 3. 2, 40, 2. 07, 400, 3. 5, 130, 2. 13, 350, 3. 3, 230, 2, 550, 3. 2, 0) In a linear model a pathloss exponent is assigned to each solid angle. In a piecewise linear model a pathloss exponent, a distance, and a second pathloss exponent is assigned to each direction 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 61

Propagation Modeling Objectives - 1 • Many tools invest heavily in propagation modeling – Databases of terrain features – Models that capture the effects of the terrain features and manmade objects • An important feature of spectrum consumption modeling is that the propagation model is a part of the model of spectrum use rather than just a part of a tool – Eliminates the need to have a common tool • Does not require a common database of terrain • Allows innovation in propagation modeling within tools • Spectrum use decisions can be made at devices – Abstraction chosen to allow tractable computations of compatibility – Common assessments of compatibility everywhere 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 62

Propagation Modeling Objectives - 2 • Modelers may use tools of their choice to create propagation maps • Propagation modeling is artful – Many features in SCM to support differentiation of propagation effects – Modeling may become a service in a system – Models may be negotiated between parties Does not require all tools to use the same methods of analyzing propagation or to have common databases of terrain data 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 63

Propagation Map – Continued – 2 Linear Log Distance Pathloss Model • Conveys the rate transmissions attenuate by direction, by providing the pathloss exponent of a log distance pathloss model 1 -meter pathloss 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 64

Propagation Map – Continued – 3 Piecewise Linear Log Distance Pathloss Model • Map stores two exponents and a breakpoint distance per direction 1 -meter pathloss 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 65

Propagation Map Data and Meaning • The map data structures Linear model Piecewise linear model • Units of exponents are dimensionless and distances are in meters • The coordinate system of propagation maps is coincident to Earth’s surface coordinates 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 66

Methods to Differentiate Propagation Effects • Map direction – Use elevations to differentiate antenna height (short range) – Use azimuths to differentiate terrain effects by direction • Antenna height rated masks – Used for long range terrestrial propagation – Height rating refers to the height of the distant antenna above the terrain – Only azimuths in the mask have relevance – A model may have multiple height rated masks and pathloss is interpolated for heights in-between • Location indexing – Assign different maps to different parts of an operating location 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 67

Height Rated Propagation Maps Antenna height Distance from shore 2 m Antenna height Distance from shore 15 km Piecewise linear model n 1 = 2 dbreakpoint = 19, 000 Piecewise linear model n 1 = 2 dbreakpoint = 7, 200 n 2 = 7. 2 n 2 = 6 Antenna height Distance from shore Piecewise linear model n 1 = 2 dbreakpoint = 25, 000 Antenna height Distance from shore 30 m 15 km 60 m 15 km Piecewise linear model n 1 = 2 dbreakpoint = 31, 000 n 2 = 8 n 2 = 7. 5 6/15/2021 10 m Doc #: 5 -14 -0052 -02 -subs 68

Using Probability with Propagation Maps • Much of the variability in received signal strength is associated with propagation • Probability may be used with propagation maps to convey the distribution Signal Strength (d. B) 9000 8000 11000 (2, 11000, 6, 0) h = 2, p = 1. 0 (2, 9000, 6, 0) h = 2, p = 0. 95 (2, 8000, 6, 0) h = 2, p = 0. 90 Antenna height Distance from shore 2 m 15 km Any of the parameters can change, here we change the breakpoint distance Distance (meters) 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 69

Important Points in Propagation Modeling • Modelers can differentiate their services by the tools they have to create models • Both transmitter and receiver models have propagation maps; rules or negotiation determine which to use – Transmitter map is used to assess system compliance to their proposed emissions – Possible rules for compatibility computations • Based on user precedence • Give preference to receiver models • … 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 70

6 – Intermodulation (IM) Mask A list of inflection points, frequency and relative power, that form a filter mask Specifies how signals amplitudes are combined for a particular order of IM distortion May be associated with a receiver or a transmitter (394, -100, 396, -50, 398, -40, 402, -40, 404, -50, 406, -100) 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 71

IM Interference • IM is the creation of frequency components that are the sum and differences of the frequency of signals that mix in non-linear components – For Example, given f 1 and f 2, f 1>f 2 • Second order IM: 2 f 1, 2 f 2, f 1+f 2, f 1 -f 2 • Third order IM: 3 f 1, 3 f 2, 2 f 1+f 2, f 1+2 f 2, 2 f 1 -f 2, 2 f 2 -f 1 • IM products may be created within a receiver or be transmitted 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 72

Receiver IM Interference • IM products are created in the RF components from adjacent band use of spectrum – that fall within the pass band of receiver and so are perceived as interference – Includes image frequencies when heterodyning is used • An IM Combining (IMC) masks defines how incoming signals combine 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 73

Using an IMC Mask • The IMC mask specifies how signals that are inputs are shaped and amplified before combining by the characteristics of the device – The portion of the input mask that falls within the bandwidth of the IMC mask is scaled by the power level of the IMC mask Input signals 6/15/2021 IMC Mask Doc #: 5 -14 -0052 -02 -subs Scaled outputs 74

Using an IMC Mask - 2 • The shaped signals are reduced to four points prior to combining them, the end points to maintain bandwidth and the two highest power points to capture amplitude 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 75

Using an IMC Mask - 3 • Combine signals two at a time – Consider the two masks for signals Sa and Sb – The IM of the sum (Sa + Sb) is computed as the sum of the frequencies and powers of each point – The IM of the difference (Sa – Sb) is computed as the difference of the frequencies and the sum of the powers but using the points in Sb in reverse order 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 76

Using an IMC Mask - 4 • Consider the intermodulation product (2 Sa – Sb) Sb Sa 2 Sa – Sb 2 Sa 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 77

Alternatives to Define IM Product • Discussions may result in other methods for creating the IM products. • Example – Input masks can be divided into multiple bins – The combining of two masks would tally the result of combining each combination of bins from the two masks – Underlay masks power level would be scaled as appropriate 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 78

Assessing Interference • Once the IM product is defined the interference is assessed like any other signal using the receivers underlay mask Reshaped mask Underlay mask Spectrum mask 6/15/2021 Mask extends the full bandwidth of the underlay Doc #: 5 -14 -0052 -02 -subs 79

Image Frequencies • The IMC mask data structure indicates it is used for image frequencies by providing the intermediate frequency (IF) and injection side – The IMC mask models the characteristics of the front end – The IF and injection side identifies the local oscillator frequency, f. LO 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 80

Image Frequencies - 2 • Rather than determining the image input to a receiver, create an image underlay mask The image underlay mask is a reflection of the underlay mask about the local oscillator frequency further shaped by the IM mask Use it as any other mask to determine interference 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 81

Transmitter IM Interference • IM products are emitted from the transmitter • The transmitter signal is an input to the IM product • Two masks are used, an IMC mask is used to show signals combine and an output mask defines how signals are amplified – IMC masks indicates the attenuation to the distant input prior to combining – The attenuated distant input is combined with the unamplified transmitter signal defined by the total power and spectrum mask combination – The output mask indicates the amplification of the IM product prior to the power map 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 82

7 – Platform The name of a platform Vehicle #27 2 -41 Command Vehicle 6/15/2021 Doc #: 5 -14 -0052 -02 -subs Specifies a facility, platform , or device where radio systems may be colocated and so interact to form IM May be either a specific platform or a class of platforms 83

8. Locations may be points, volumes, trajectories, or orbits (piecewise tracks) Identifies where systems are operated 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 84

Location Modeling • Conveys the location or region where RF components may be • When an area or volume is given it is assumed that the transmitter or receiver can be anywhere in that space • Spectrum consumption models do not model terrain and where appropriate terrain effects should be captured in the model’s propagation and power maps 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 85

Locations • Point – a fixed location, < , , a> • Terrestrial surface area – a region assumed on the Earth’s surface with fixed height antennas – Point surface area is defined by a point, < , , a, ah> – Circular area is define by a point and a radius, < , , a, r, ah> – Convex polygon area is defined by a series of points that are connected in the order given with the last connected to the first, <( 0, a 0, 1, a 1, …, n-1, a n-1)ah> • Altitudes of locations between points are interpolated – May specify antenna height relative to ground or relative to average terrain height 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 86

Locations - 2 • Volume Modeling – Cylinders are specified by a point, a radius and a height < , , a, r, h> – Polyhedrons are specified by a series of points and a height <( 0, a 0, 1, a 1, …, n-1, a n-1), h> • Lower surface defined by the lowest altitude – Lower and upper surfaces are parallel to the WGS 84 tangent plane • At a cylinder center • At centroid of the polyhedron for a plane the intersects the lowest point 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 87

Locations - 3 • Track – Specified by a point, heading, and velocity < , , a, , , v> 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 88

9 – Start Time • Used to identify the start of a model and periodic variations of use • Start time is referenced to Coordinate Universal Time (UTC) <YYYY, MM, DD, hh, mm, ss. s, hh 0, mm 0> • Periodic use is specified by three durations <durationd, durationon, durationoff> – Durationd is the displacement of the first on period from the start time – Durationon and durationoff are what their name implies and they repeat 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 89

Start Time - 2 • Durations are expressed in the ISO 8601 format of Pn. Yn. Mn. DTn. Hn. Mn. S where – – – – 6/15/2021 n. Y is the number of years, n. M is the number of months, n. D is the number of days, n. H is the number of hours, n. M after the T value is the number of minutes, and n. S is the number of seconds. The P designator is always present. The T designator is only used when one of the time elements of hours, minutes, or seconds is present. Doc #: 5 -14 -0052 -02 -subs 90

10 – End Time • Used to identify when the model ends • End time is referenced to Coordinate Universal Time (UTC) YYYY, MM, DD, hh, mm, ss. s, hh 0, mm 0> • The end time should follow the start time 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 91

11 – Minimum Power Spectral Flux Density A reference value used with a transmitter model to imply the extent of receiver locations -150 d. BW/m 2/Hz 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 92

12 – Protocol or Policy Used to specify behaviors that can be exploited or behaviors that are compatible Primary TDMA User t DSA users vacate the channel at the TDMA boundary of the primary user A cooperative DSA Use 6/15/2021 t Doc #: 5 -14 -0052 -02 -subs 93

What is a spectrum policy for cognitive radio? • Policy – a) A set of rules governing the behavior of a system. NOTE 1―Policies may originate from regulators, manufacturers, developers, network and system operators, and system users. A policy may define, for example, allowed frequency bands, waveforms, power levels, and secondary user protocols. – b) A machine interpretable instantiation of policy as defined in (a) NOTE 2―Policies are normally applied post manufacturing of the radio as a configuration to a specific service application. NOTE 3—Definition b) recognizes that in some contexts the term “policy” is assumed to refer to machine understandable policies IEEE STD 1900. 1, 2008 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 94

What is a spectrum policy for cognitive radio? - 2 • Cognitive Radio– a) A type of radio in which communication systems are aware of their environment and internal state and can make decisions about their radio operating behavior based on that information and predefined objectives NOTE ― The environmental information may or may not include location information related to communication systems. – b) Cognitive radio [as defined in item a)] that uses software -defined radio, adaptive radio, and other technologies to adjust automatically its behavior or operations to achieve desired objectives IEEE STD 1900. 1, 2008 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 95

Recall Model and Collection Functions • System Model – Consists of transmitter and receiver models that are part of a system • Collective Consumption Listing – Lists uses of spectrum by systems, transmitters and receivers – Heading identifies the time, space, and frequencies over which the list is complete • Spectrum Authorization Listing – List of system, transmitter, and receiver models identify spectrum boundaries within which use is authorized • Spectrum Constraint Listing – List of system, transmitter, and receiver models identify existing uses of spectrum that have precedence with which new uses must be compatible 6/15/2021 Doc #: 5 -14 -0052 -02 -subs Heading identifies the limits in time, space, and frequencies over which the list applies 96

What is a protocol? • • • protocol (1) (supervisory control, data acquisition, and automatic control) A strict procedure required to initiate and maintain communication. (SWG/SUB/PE) 999 -1992 w, C 37. 1 -1994, C 37. 100 -1992 (2) A formal set of conventions governing the format and relative timing of message exchange between two communications terminals. See also: control procedure. (LM/COM) 168 -1956 w (3) (software) A set of conventions that govern the interaction of processes, devices, and other components within a system. (C) 610. 12 -1990 (4) (STEbus) The signaling rules used to convey information or commands between boards connected to the bus. (C/MM) 1000 -1987 r (5) (MULTIBUS II) The set of signaling rules used to convey information between agents. (C/MM) 12961987 s (6) A set of semantic and syntactic rules that determine the behavior of entities that interact. (C/PA) 14252 -1996 (7) A set of rules and formats (semantic and syntactic) that determines the communication behavior of simulation applications. (DIS/C) 1278. 1 -1995, 1278. 2 -1995 (8) A set of conventions or rules that govern the interactions of processes or applications within a computer system or network. (ATLAS) 1232 -1995 (9) (A) A formal set of conventions governing the format and relative timing of message exchange in a computer system. (B) A set of semantic and syntactic rules that determine the behavior of functional units in achieving meaningful communication. (C) 610. 7 -1995, 610. 10 -1994 IEEE STD 100 (10) A set of semantic and syntactic rules for exchanging information. (C) 1003. 5 -1999 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 97

Policy or Protocol • Enables finer resolution sharing through behaviors at components – Means to specify how spectrum sensing may be used to inform spectrum use decisions – Means to exploit reuse opportunities that come from knowing the specific behaviors of incumbents • Protocols specify access mechanisms while policies specify conditions for use – policy driven systems may choose their own access mechanism • General enough that physical layer characteristics can also be identified, e. g. polarization, adaptive antennas, … 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 98

Protocol or Policy - 2 • Identifies the behavior of the transmitter – The behavior of the system modeled in transmitter models – The behavior of distant transmitters in receiver models • Consists of – A name for the policy or protocol – A list a parameters • Assumes another authority defines the policy or protocol names and the required parameters 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 99

Policy Example • A policy is generalized behavior with no restriction on the protocols used by the system for arbitrating its own access • Listen before talk – Sense the channel for a particular power threshold, pth • A duration of non-use indicates availability, tf – A sensing period for verifying availability, ts – An abandonment time, ta • Policy Description 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 100

A protocol example • The scenario – Multiple co-located MANETs – Goal is to ensure the networks share the channel Each circle is a radio and each color is a network and all share the same channel 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 101

The protocol Synchronous Collision Resolution CR Signaling Transmission Slot … • Time slotted channels with common time boundaries • Nodes with packets to send contend in every slot • Signaling is used to arbitrate contention A paradigm not a specific design DEMONSTRATION 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 102

Some Results All nodes have a fair chance to gain access Nodes outlined in yellow are the contention winners 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 103

Example giving precedence to a user • The scenario – Multiple co-located MANETs with one a primary user – Goal is to ensure primary users get precedence and secondary users can use whatever spectrum the primary users do not use 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 104

Differentiating Priority of Access DEMONSTRATION 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 105

The Result • The primary always get precedence in access • Secondary users can fill in the spaces around the primary user 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 106

Specifying the Protocol Name Parameters <SCR, 0. 07, 0. 05, 40> Signal Slot Size Signal Duration Transmission Slot Duration Other parameters may be required e. g. , timing, signal shape, priority level, … <SCR PS, 0. 05, 0. 035, 2> Name 6/15/2021 Parameters Doc #: 5 -14 -0052 -02 -subs 107

Indexing • Indexing enables the combining of sets of constructs in the same model contingent on particular conditions – Constructs are associated with each other using an index number – Location indexing combines the location, start time, end time, power map, and propagation map – Policy and protocol indexing combine underlay masks with a particular protocol or policy 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 108

A physical layer example • Polarization can support sharing such as Right Circular Polarized signals can coexist with Left Circular Polarized Signals • Let the two versions of polarization be named <LCP> and <RCP> • An LCP system could convey its compatibility by – Using <LCP> in the Policy or Protocol Construct in the transmitter model – Providing two underlay mask • One for random polarization • A more permissive mask for right circular polarization indexed to a Policy or Protocol construct with the <RCP> named value • An RCP system would do the same switching <LCP> and <RCP> 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 109

What is the difference between 5. 1 and 5. 2? • The SCM of 1900. 5. 2 can specify – The boundaries of available spectrum – Constraints to spectrum use – Behaviors radios must use to share spectrum • Devices can receive SCM as policy and can autonomously determine spectrum use that is compliant • In 1900. 5. 2 – Boundaries and the conditions for use are the means to change policy but the rules for determining compliance are unchanging – It is assumed that users or radios know whether they can execute a named behavior • 1900. 5. 1 differentiates itself from 1900. 5. 2 in that a policy language can teach users or a radio the rules of the policy and how to behave 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 110

MODELING 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 111

Summary of Modeling Transmission Power Spectral Flux Density • Goal is to define what is happening in the ether • Captured using three constructs – Total power – Spectrum mask – Power map • Constructs may trade power levels so long as they get the power spectral flux density correct • Different sets of models may be assigned to Power Spectral Flux Density of a transmission Transmitter Total Power + + – Different transmitters – Different locations 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 112

Receiver Power Spectral Flux Density • Captured using three constructs – Total power – Underlay mask – Power map • May divide a model up into different spaces with each having a different set of constructs for power spectral flux density • Systems having multiple receivers – Model each individually – Model a set of mobile receivers (e. g. data links and mobile ad hoc networks) by a single model and a space Allowed Power Spectral Flux Density of interference Receiver Total Power + + • Receiver modeling is not well defined 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 113

Combining Constructs into Models Modeling constructs are found in transmitter and receiver models and in system and collection headings Constructs Transmitter define emissions _______ Constructs define interference Receiver _______ System _______ Transmitter_1 Transmitter_2 Transmitter_n Receiver_1 Receiver_2 Receiver_m End of System Collection _______ System_1 System_2 System_i Transmitter_1 Transmitter_2 Transmitter_j Receiver_1 Receiver_2 Receiver_k End of Collection Proposal provides an XML schema for this type of model construction “Spectrum Consumption Modeling Markup Language” (SCMML) 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 114

Models and Lists Supported by SCMML • Transmitter and Receiver Models • System Model – Constructs in heading define the boundaries of system operation – Lists transmitter and receiver models with more limiting constructs • Collective Consumption Listing – Constructs in heading define the limits to which the collection is complete – Lists systems, transmitters and receivers of spectrum consumers that consume spectrum within the limits of the collection • Spectrum Authorization Listing – Constructs in the heading define the limits of the overall authorization – The lists of system, transmitter, and receiver models identify available spectrum • Spectrum Constraint Listing – Constructs in the heading define the limits of the collection of constraints – The lists of system, transmitter, and receiver models identify existing uses of spectrum that have precedence 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 115

General Process for Computing Compatibility • Determine if uses will overlap in time and spectrum • Determine the constraining points (the point of primary operation and the point of secondary operation that most restrict the secondary user) Constraining • Compute the allowed transmit secondarypower of the secondary Secondary mobile user Constraining primary receiver transmitter Primary broadcast user 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 116

Determining Compatible Reuse d 1 – distance between the primary transmitter and the constraining point d 2 – distance between the secondary transmitter and the constraining point PM – Power margin accounting for masks, underlays, and propagation (prop) 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 117

Way Ahead • Draft standard has not yet been completed and so not ready for typical comment and correction process • Recommend – Interested participants can make suggestions to the current incomplete draft and provide directly to me – I will update and complete the draft as time allows – Once complete version is made, begin comment and resolution process 6/15/2021 Doc #: 5 -14 -0052 -02 -subs 118