[Docs] [txt|pdf|xml|html] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits] [IPR]

Versions: (draft-probasco-paws-problem-stmt-usecases-rqmts) 00 01 02 03 04 05 06 RFC 6953

Working Group Draft                                     S. Probasco, Ed.
Internet-Draft                                                  G. Bajko
Intended status: Informational                                  B. Patil
Expires: March 12, 2012                                            Nokia
                                                                B. Rosen
                                                                 Neustar
                                                       September 9, 2011


    Protocol to Access White Space database: PS, use cases and rqmts
             draft-ietf-paws-problem-stmt-usecases-rqmts-00

Abstract

   Portions of the radio spectrum that are allocated to a licensed,
   primary user but are unused or unoccupied at specific locations and
   times are defined as "white space".  The concept of allowing
   secondary transmissions (licensed or unlicensed) in white space is a
   technique to "unlock" existing spectrum for new use.  An obvious
   requirement is that these secondary transmissions do not interfere
   with the primary use of the spectrum.  One approach to using the
   white space spectrum at a given time and location is to verify with a
   database available channels.

   This document describes the concept of TV White Spaces.  It also
   describes the problems that need to be addressed for enabling the use
   of the primary user owned white space spectrum for secondary users,
   without causing interference, by querying a database which knows the
   channel availability at any given location and time.  A number of
   possible use cases of this spectrum and derived requirements are also
   described.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on March 12, 2012.



Probasco, et al.         Expires March 12, 2012                 [Page 1]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions and Terminology  . . . . . . . . . . . . . . . . .  5
     2.1.  Conventions Used in This Document  . . . . . . . . . . . .  5
     2.2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  5
   3.  Prior Work . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     3.1.  The concept of Cognitive Radio . . . . . . . . . . . . . .  6
     3.2.  Background information on white space in US  . . . . . . .  6
     3.3.  Air Interfaces . . . . . . . . . . . . . . . . . . . . . .  7
   4.  Use cases  . . . . . . . . . . . . . . . . . . . . . . . . . .  7
     4.1.  TVWS database discovery  . . . . . . . . . . . . . . . . .  7
     4.2.  Hotspot: urban internet connectivity service . . . . . . .  8
     4.3.  Wide-Area or Rural internet broadband access . . . . . . . 10
     4.4.  Offloading: moving traffic to a white space network  . . . 12
     4.5.  TVWS for backhaul  . . . . . . . . . . . . . . . . . . . . 14
     4.6.  Location based service usage scenario  . . . . . . . . . . 15
     4.7.  Rapid deployed network for emergency scenario  . . . . . . 17
   5.  Problem Statement  . . . . . . . . . . . . . . . . . . . . . . 18
     5.1.  Global applicability . . . . . . . . . . . . . . . . . . . 19
     5.2.  Database discovery . . . . . . . . . . . . . . . . . . . . 21
     5.3.  Protocol . . . . . . . . . . . . . . . . . . . . . . . . . 21
     5.4.  Data model definition  . . . . . . . . . . . . . . . . . . 21
   6.  Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 21
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 21
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 21
   9.  Summary and Conclusion . . . . . . . . . . . . . . . . . . . . 22
   10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22
   11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
     11.1. Normative References . . . . . . . . . . . . . . . . . . . 23
     11.2. Informative References . . . . . . . . . . . . . . . . . . 23
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 24



Probasco, et al.         Expires March 12, 2012                 [Page 2]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


1.  Introduction

   Wireless spectrum is a commodity that is regulated by governments.
   The spectrum is used for various purposes, which include
   entertainment (e.g. radio and television), communication (telephony
   and Internet access), military (radars etc.) and, navigation
   (satellite communication, GPS).  Portions of the radio spectrum that
   are allocated to a licensed, primary user but are unused or
   unoccupied at specific locations and times are defined as "white
   space".  The concept of allowing secondary transmissions (licensed or
   unlicensed) in white space is a technique to "unlock" existing
   spectrum for new use.  An obvious requirement is that these secondary
   transmissions do not interfere with the primary use of the spectrum.
   One interesting observation is that often, in a given physical
   location, the primary user(s) may not be using the entire band
   allocated to them.  The available spectrum for a secondary use would
   then depend on the location of the secondary user.  The fundamental
   issue is how to determine for a specific location and specific time,
   if any of the primary spectrum is available for secondary use.
   Academia and Industry have studied multiple cognitive radio
   mechanisms for use in such a scenario.  One simple mechanism is to
   use a geospatial database that records the primary users occupation,
   and require the secondary users to check the database prior to
   selecting what part of the spectrum they use.  Such databases could
   be available on the Internet for query by secondary users.

   Spectrum useable for data communications, especially wireless
   Internet communications, is scarce.  One area which has received much
   attention globally is the TV white space: portions of the TV band
   that are not used by broadcasters in a given area.  In 2008 the
   United States regulator (the FCC) took initial steps when they
   published their first ruling on the use of TV white space, and then
   followed it up with a final ruling in 2010 [FCC Ruling].  Finland
   passed an Act in 2009 enabling testing of cognitive radio systems in
   the TV white space.  The ECC has completed Report 159 [ECC Report
   159] containing requirements for operation of cognitive radio systems
   in the TV white space.  Ofcom published in 2004 their Spectrum
   Framework Review [Spectrum Framework Review] and their Digital
   Dividend Review [DDR] in 2005, and have followed up with a proposal
   to access TV white space.  More countries are expected to provide
   access to their TV spectrum in similar ways.  Any entity holding
   spectrum that is not densely used may be asked to give it up in one
   way or another for more intensive use.  Providing a mechanism by
   which secondary users share the spectrum with the primary user is
   attractive in many bands in many countries.

   Television transmission until now has primarily been analog.  The
   switch to digital transmission has begun.  As a result the spectrum



Probasco, et al.         Expires March 12, 2012                 [Page 3]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   allocated for television transmission can now be more effectively
   used.  Unused channels and bands between channels can be used as long
   as they do not interfere with the primary service for which that
   channel is allocated.  While urban areas tend to have dense usage of
   spectrum and a number of TV channels, the same is not true in rural
   and semi-urban areas.  There can be a number of unused TV channels in
   such areas that can be used for other services.  The figure below
   shows TV white space within the lower UHF band:


        Avg  |
        usage|                             |-------------- White Space
             |                    |    |   |   |  |
          0.6|                   ||    ||  V   V  ||
             |                   ||   |||    |    ||
          0.4|                   ||   ||||   |    ||
             |                   ||   ||||   |    ||<----TV transmission
          0.2|                   ||   ||||   |    ||
             |----------------------------------------
             400     500       600      700       800
                      Frequency in MHz ->



                Figure 1: High level view of TV White Space

   The fundamental issue is how to determine for a specific location and
   specific time if any of the spectrum is available for secondary use.
   There are two dimensions of use that may be interesting: space (the
   area in which a secondary user would not interfere with a primary
   user, and time: when the secondary use would not interfere with the
   primary use.  In this discussion, we consider the time element to be
   relatively long term (hours in a day) rather than short term
   (fractions of a second).  Location in this discussion is geolocation:
   where the transmitters (and sometimes receivers) are located relative
   to one another.  In operation, the database records the existing
   user's transmitter (and some times receiver) locations along with
   basic transmission characteristics such as antenna height, and
   sometimes power.  Using rules established by the regulator, the
   database calculates an exclusion zone for each authorized primary
   user, and attaches a time schedule to that use.  The secondary user
   queries the database with its location.  The database intersects the
   exclusion zones with the queried location, and returns the portion of
   the spectrum not in any exclusion zone.  Such methods of geospatial
   database query to avoid interference have been shown to achieve
   favorable results, and are thus the basis for rulings by the FCC and
   reports from ECC and Ofcom.  In any country, the rules for which
   primary entities are entitled to protection, how the exclusion zones



Probasco, et al.         Expires March 12, 2012                 [Page 4]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   are calculated, and what the limits of use by secondary entities are
   may vary.  However, the fundamental notion of recording primary
   users, calculating exclusion zones, querying by location and
   returning available spectrum (and the schedule for that spectrum) are
   common

   This document includes the problem statement, use cases and
   requirements associated with the use of white space spectrum by
   secondary users via a database query protocol.


2.  Conventions and Terminology

2.1.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.2.  Terminology

   Database

      In the context of white space and cognitive radio technologies,
      the database is an entity which contains current information about
      available spectrum at any given location and other types of
      information.

   Location Based Service

      An application or device which provides data, information or
      service to a user based on their location.

   Master Device

      A device which queries the WS Database to find out the available
      operating channels.

   Protected Entity

      A primary user of white space spectrum which is afforded
      protection against interference by secondary users (white space
      devices) for its use in a given area and time.

   Protected Contour

      The exclusion area for a Protected Entity, held in the database
      and expressed as a polygon with geospatial points as the vertices.



Probasco, et al.         Expires March 12, 2012                 [Page 5]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   Slave Device

      A device which uses the spectrum made available by a master
      device.

   TV White Space

      TV white space refers specifically to radio spectrum which has
      been allocated for TV broadcast, but is not occupied by a TV
      broadcast, or other licensed user (such as a wireless microphone),
      at a specific location and time.

   White Space

      Radio spectrum which has been allocated for some primary use, but
      is not fully occupied by that primary use at a specific location
      and time.

   White Space Device

      A device which is a secondary user of some part of white space
      spectrum.  A white space device can be an access point, base
      station, a portable device or similar.  In this context, a white
      space device is required to query a database with its location to
      obtain information about available spectrum.


3.  Prior Work

3.1.  The concept of Cognitive Radio

   A cognitive radio uses knowledge of the local radio environment to
   dynamically adapt its own configuration and function properly in a
   changing radio environment.  Knowledge of the local radio environment
   can come from various technology mechanisms including sensing
   (attempting to ascertain primary users by listening for them within
   the spectrum), location determination and internet connectivity to a
   database to learn the details of the local radio environment.  TV
   White Space is one implementation of cognitive radio.  Because a
   cognitive radio adapts itself to the available spectrum in a manner
   that prevents the creation of harmful interference, the spectrum can
   be shared among different radio users.

3.2.  Background information on white space in US

   Television transmission in the United States has moved to the use of
   digital signals as of June 12, 2009.  Since June 13, 2009, all full-
   power U.S. television stations have broadcast over-the-air signals in



Probasco, et al.         Expires March 12, 2012                 [Page 6]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   digital only.  An important benefit of the switch to all-digital
   broadcasting is that it freed up parts of the valuable broadcast
   spectrum.  More information about the switch to digital transmission
   is at : [DTV].

   With the switch to digital transmission for TV, the guard bands that
   existed to protect the signals between stations can now be used for
   other purposes.  The FCC has made this spectrum available for
   unlicensed use and this is generally referred to as white space.
   Please see the details of the FCC ruling and regulations in [FCC
   Ruling].  The spectrum can be used to provide wireless broadband as
   an example.  The term "Super-Wifi" is also used to describe this
   spectrum and potential for providing wifi type of service.

3.3.  Air Interfaces

   Efforts are ongoing to specify air-interfaces for use in white space
   spectrum.  IEEEs 802.11af task group is currently working on one such
   specification.  IEEE 802.22 is another example.  Other air interfaces
   could be specified in the future such as LTE.


4.  Use cases

   There are many potential use cases that could be considered for the
   TV white space spectrum.  Providing broadband internet access in
   hotspots, rural and underserved areas are examples.  Available
   channels may also be used to provide internet 'backhaul' for
   traditional Wi-Fi hotspots, or by towns and cities to monitor/control
   traffic lights or read utility meters.  Still other use cases include
   the ability to offload data traffic from another internet access
   network (e.g. 3G cellular network) or to deliver location based
   services.  Some of these use cases are described in the following
   sections.

4.1.  TVWS database discovery

   This use case is preliminary to creating a radio network using TV
   white space; it is a prerequisite to other use cases.  The radio
   network is created by a master device which can be an access point
   that establishes Hotspot coverage, a base station that establish
   cellular coverage, or a device that establishes a peer-to-peer or ad-
   hoc network.  Before the master device can transmit in TV white space
   spectrum, it must contact a trusted database where the device can
   learn if any channels are available for it to use.

   In the simplest case the radio device is pre-programmed with the
   internet address of at least one trusted database.  The device can



Probasco, et al.         Expires March 12, 2012                 [Page 7]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   establish contact with a trusted database using one of the pre-
   programmed internet addresses and establish a TV white space network
   (as described in one of the following use cases).

   If the radio device (master) does not have a pre-programmed address
   for a trusted white space database, or if the trusted database at the
   pre-programmed address is not responsive, or perhaps the trusted
   database does not provide service for the radio device's current
   location, or at the user's choice, the device may attempt to
   "discover" a trusted database which provides service at the current
   location.

   1.  The master is connected to the internet by any means other than
       using the TV white space radio.

   2.  The master constructs and broadcasts a query message over the
       internet and waits for responses.

   3.  If no acceptable response is received within a pre-configured
       time limit, the device concludes that no trusted database is
       available.  If one or more response is received, the device
       evaluates the response to determine if a trusted database can be
       identified where the device is able to register and receive
       service from the database.

4.2.  Hotspot: urban internet connectivity service

   In this use case internet connectivity service is provided in a
   "hotspot" to local users.  Typical deployment scenarios include urban
   areas where internet connectivity is provided to local businesses and
   residents, and campus environments where internet connectivity is
   provided to local buildings and relatively small outdoor areas.  This
   deployment scenario is typically characterized by multiple masters
   (APs or hotspots) in close proximity, with low antenna height, cells
   with relatively small radius (a few kilometers or less), and limited
   numbers of available radio channels.  Many of the masters/APs are
   assumed to be individually deployed and operated, i.e. there is no
   coordination between many of the masters/APs.  The masters/APs in
   this scenario use a TDD radio technology and transmit at or below a
   relatively low transmit power threshold.  Each master/AP has a
   connection to the internet and provides internet connectivity to
   multiple end user or slave devices.

   The figure below shows an example deployment of this scenario.







Probasco, et al.         Expires March 12, 2012                 [Page 8]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


    -------
    |Slave|\                  \|/                            ----------
    |Dev 1| (TDD AirIF)        |                             |Database|
    -------            \       |                     .---.   /---------
       o                \    |-|---------|          (     ) /
       o                     |  Master   |         /       \
       o                 /   |           |========( Internet )
       o                /    |-----------|         \        /
    -------  (TDD AirIF)                            (      )
    |Slave| /                                        (----)
    |Dev n|
    -------


          Figure 2: Hotspot service using TV white space spectrum

   Once a master/AP has been correctly installed and configured, a
   simplified power up and operation scenario utilizing TV White Space
   to provide Internet connectivity service consists of the following
   steps:

   1.  The master/AP powers up; however its WS radio and all other WS
       capable devices will power up in idle/listen only mode (no active
       transmissions on the WS frequency band).

   2.  The master/AP has Internet connectivity and establishes a
       connection to a trusted white space database (see use case "TVWS
       database discovery" above).

   3.  The master/AP registers its geolocation, address, contact
       information, etc. associated with the owner/operator of the
       master/AP with the trusted database administrator (if not
       currently registered).  Depending upon local regulator policy,
       the DB administrator may be required to store and forward the
       registration information to the regulatory authority.

   4.  Following the registration process, the master/AP will send a
       query to the trusted database requesting a list of available WS
       channels based upon its geolocation.

   5.  If the master/AP has been previously authenticated, the database
       responds with a list of available white space channels that the
       master may use, and optionally a duration of time for their use.

   6.  Once the master/AP authenticates the WS channel list response
       message from the database, the AP selects an available WS
       channel(s) from the list.




Probasco, et al.         Expires March 12, 2012                 [Page 9]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   7.  The master/AP acknowledges to the database which of the available
       WS channels it has selected for its operation.  The database is
       updated with the information provided by the master/AP.

   8.  The slave or user device scans the TV bands to locate a master/AP
       transmission, and associates with the AP.  The slave/user device
       queries the master for a channel list, based on the slaves'
       geolocation.

   9.  The master provides the list of channels locally available to the
       slave/user device.  If the channel that the user terminal is
       currently using is not included in the list of locally available
       channels, the slave/user device ceases all operation on its
       current channel.  The slave/user device may scan for another AP
       transmission on a different channel.

4.3.  Wide-Area or Rural internet broadband access

   In this use case, internet broadband access is provided as a Wide-
   Area Network (WAN) or Wireless Regional Area Network (WRAN).  A
   typical deployment scenario is a wide area or rural area, where
   internet broadband access is provided to local businesses and
   residents from a master (i.e.  BS) connected to the internet.  This
   deployment scenario is typically characterized by one or more fixed
   master(s)/BS(s), cells with relatively large radius (tens of
   kilometers, up to 100 km), and a number of available radio channels.
   Some of the masters/BSs may be deployed and operated by a single
   entity, i.e. there can be centralized coordination between these
   masters/BSs, whereas other masters/BSs may be deployed and operated
   by operators competing for the radio channels in a license-exempt
   TVWS environment where decentralized coordination using the air-
   interface would be required.  The BS in this scenario use a TDD radio
   technology and transmit at or below a transmit power limit
   established by the local regulator.  Each base station has a
   connection to the internet and provides internet connectivity to
   multiple slave/end-user devices.  End user terminals or devices may
   be fixed or portable.

   The figure below shows an example deployment of this scenario.












Probasco, et al.         Expires March 12, 2012                [Page 10]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


      -------
      |Slave|\                \|/                             ----------
      |Dev 1| (TDD AirIF)      |                              |Database|
      -------          \       |                     .---.   /----------
         o              \    |-|---------|          (     ) /
         o                   |   Master  |         /       \
         o               /   |   (BS)    |========( Internet )
         o              /    |-----------|         \        /
      -------  (TDD AirIF)                          (      )
      |Slave| /                                      (----)
      |Dev n|
      -------


      Figure 3: Rural internet broadband access using TV white space
                                 spectrum

   Once the master/BS has been professionally installed and configured,
   a simplified power up and operation scenario utilizing TV White Space
   to provide rural internet broadband access consists of the following
   steps:

   1.  The master/BS powers up; however its WS radio and all other WS
       capable devices will power up in idle/listen only mode (No active
       transmissions on the WS frequency band)

   2.  The master/BS has internet connectivity and establishes a
       connection to a trusted white space database (see use case "TVWS
       database discovery" above).

   3.  The master/BS registers its geolocation, address, contact
       information, etc. associated with the owner/operator of the
       master/BS with the trusted database service (if not currently
       registered).  Meanwhile the DB administrator may be required to
       store and forward the registration information to the regulatory
       authority.  If a trusted white space database administrator is
       not discovered, further operation of the WRAN may be allowed
       according to local regulator policy (in this case operation of
       the WRAN is outside the scope of the PAWS protocol).

   4.  Following the registration process, the master/BS will send a
       query to the trusted database requesting a list of available WS
       channels based upon its geolocation.

   5.  If the master/BS has been previously authenticated, the database
       responds with a list of available white space channels that may
       be used and optionally a maximum transmit power (EIRP) for each
       channel and a duration of time the channel may be used.



Probasco, et al.         Expires March 12, 2012                [Page 11]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   6.  Once the master/BS authenticates the WS channel list response
       message from the database, the master/BS selects an available WS
       channel(s) from the list.  The operator may disallow some
       channels from the list to suit local needs if required.

   7.  The master/BS acknowledges to the database which of the available
       WS channels the BS has selected for its operation.  The database
       is updated with the information provided by the BS.

   8.  The slave or user device scans the TV bands to locate a WRAN
       transmission, and associates with the master/BS.  The slave/user
       device provides its geolocation to the BS which, in turn, queries
       the database for a list of channels available at the slaves'
       geolocation.

   9.  Once this list of available channels is received from the
       database by the master, the latter will decide, based on the list
       of available channels for all its other associated slaves whether
       it should continue operation on its current channel or change
       channel to accommodate the new slave in case this channel is not
       available at its location.  The master will notify all its
       associated slaves/user devices of the new channel to move to if
       operation needs to change channel.  If the channel that the user
       terminal is currently using is not included in the list of
       locally available channels, the master will drop its association
       with the slave/user device so that it ceases all operation on its
       current channel and indicate the new operating channel before
       dropping the link if a change has been decided.  The slave/user
       device may move to the indicated new channel if so indicated or
       scan for another WRAN transmission on a different channel.

4.4.  Offloading: moving traffic to a white space network

   In this use case internet connectivity service is provided over TV
   white space as a supplemental or alternative datapath to a 3G or
   other internet connection.  In a typical deployment scenario an end
   user has a primary internet connection such as a 3G cellular packet
   data subscription.  The user wants to use a widget or application to
   stream video from an online service (e.g. youtube) to their device.
   Before the widget starts the streaming connection it checks
   connectivity options available at the current time and location.
   Both 3G cellular data is available as well as TVWS connectivity (the
   user is within coverage of a TVWS master -- hotspot, WAN, WRAN or
   similar).  The user may decide for many and various reasons such as
   cost, RF coverage, data caps, etc. to prefer the TVWS connection over
   the 3G cellular data connection.  Either by user selection,
   preconfigured preferences, or other algorithm, the streaming session
   is started over the TVWS internet connection instead of the 3G



Probasco, et al.         Expires March 12, 2012                [Page 12]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   cellular connection.  This deployment scenario is typically
   characterized by a TVWS master/AP providing local coverage in the
   same geographical area as a 3G cellular system.  The master/AP is
   assumed to be individually deployed and operated, i.e. the master/AP
   is deployed and operated by the user at his home or perhaps by a
   small business such as a coffee shop.  The master/AP has a connection
   to the internet and provides internet connectivity to the slave/
   end-user's device.

   The figure below shows an example deployment of this scenario.


                              \|/
                               |
                               |
                             |-|---------|
                             | Master/AP |\
                            /| Router    | \
                  Streaming/ |-----------|  \
       --------  /                           \               -----------
       |Slave/| /                             \      (----)  | Database |
       |WS Dev|                                \    (      ) /----------
        ------- \                               \  /        \
                 \                               X( Internet )
                  \                             /  \        /
                   Signaling  \|/              /    (      )\
                          \    |              /      (----)  \----------
                           \   |             /                | YouTube |
                            \|-|---------|  /                 ----------
                             | Master /  | /
                             | 3G BTS    |/
                             |-----------|


       Figure 4: Offloading: moving traffic to a white space network

   Once a dual or multi mode device (3G + TVWS) is connected to a 3G
   network, a simplified operation scenario of offloading selected
   content such as video stream from the 3G connection to the TWVS
   connection consists of the following steps:

   1.  The dual mode (or multi mode) device (3G + TVWS) is connected to
       a 3G network.  The device has contacted a trusted database to
       discover the list of available TV channels at its current
       location.  The device has located a TVWS master/AP operating on
       an available channel and has associated or connected with the
       TVWS master/AP.




Probasco, et al.         Expires March 12, 2012                [Page 13]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   2.  The user activates a widget or application that streams video
       from YouTube.  The widget connects to YouTube over 3G cellular
       data.  The user browses content and searches for video
       selections.

   3.  The user selects a video for streaming using the widget's
       controls.  Before the widget initiates a streaming session, the
       widget checks the available connections in the dual mode device
       and finds a TVWS master/AP is connected.

   4.  Using either input from the user or pre-defined profile
       preferences, the widget selects the TVWS master/AP as the
       connection to stream the video.

4.5.  TVWS for backhaul

   In this use case internet connectivity service is provided to users
   over a traditional wireless protocol, one common example is Wi-Fi.
   The TV white space network provides the "backhaul" or connection from
   the Wi-Fi to the internet.  In a typical deployment scenario an end
   user has a device with a radio such as Wi-Fi.  A service provider or
   shop owner wants to provide Wi-Fi internet service for their
   customers.  The location where the service provider wants to provide
   Wi-Fi is within range of a TVWS master (e.g.  Hotspot or Wide-Area/
   Rural network).  The service provider installs a TVWS slave device
   and connects this slave to a Wi-Fi access point.  This deployment
   scenario is typically characterized by a TVWS master/AP/BS providing
   local coverage.  The master/AP has a connection to the internet and
   provides internet connectivity to the slave device.  The slave device
   is then 'bridged' to a Wi-Fi network

   The figure below shows an example deployment of this scenario.


                        \|/     white    \|/    \|/   WiFi  \|/
                         |      space     |      |           |
                         |                |      |         |-|----|
       |--------|      |-|---------|    |-|------|-|       | WiFi |
       |        |      | Master    |    |  Slave   |       | Dev  |
       |internet|------| (AP/BS)   |    |  Bridge  |       |------|
       |        |      |           |    | to WiFi  |
       |--------|      |-----------|    |----------|        \|/
                                                             |
                                                           |-|----|
                                                           | WiFi |
                                                           | Dev  |
                                                           |------|




Probasco, et al.         Expires March 12, 2012                [Page 14]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


                        Figure 5: TVWS for backhaul

   Once the bridged device (TVWS+WiFi) is connected to a master and TVWS
   network, a simplified operation scenario of backhaul for WiFi
   consists of the following steps:

   1.  A bridged device (TVWS+WiFi) is connected to a master device
       operating in the TVWS.  The bridged device operates as a slave
       device in either Hotspot or Wide-Area/Rural internet use cases
       described above.

   2.  Once the slave device is connected to the master, the Wi-Fi
       access point configures its internet settings automatically based
       on the backhaul connection (i.e. it uses DHCP).

   3.  End users connect their WiFi device to the bridged device and
       receive internet connectivity.

4.6.  Location based service usage scenario

   The owner of a shopping mall wants to provide internet access to
   customers when they are at the shopping mall.  His internet service
   provider (ISP) recommends using master/AP devices in the TV white
   space frequency band since these radios will have good propagation
   characteristics, and thus will require fewer devices, and also
   because the frequency band used by traditional Wi-Fi is crowded with
   users such as individual stores operating their own Wi-Fi network and
   also Bluetooth devices.  The ISP installs APs in each large store in
   the mall, and several other APs throughout the mall building.  For
   each AP, the professional installer programs the location (latitude
   and longitude) of the device.  Special tools are required to
   determine the location, since typical GPS receivers do not function
   indoors.  When each AP is powered on, the radio does not transmit
   initially.  The AP contacts a white space database, using its wired
   internet connection, and provides its programmed location coordinates
   plus other information required by the database.  A reply is received
   by the AP from the database containing a list of available channels
   where the AP can operate its transmitter.  The AP selects a channel
   for operation and notifies the database, which records information
   about the AP including the identity of the AP and its location
   coordinates.  The AP activates its radio and begins to function as a
   typical wireless AP, providing internet access to connected devices.

   A user has a slave device that is capable of operating in the TV
   white spaces frequency band.  A typical device would be a smartphone
   with multiple radios, including a cellular radio, a Wi-Fi radio, and
   TV white space radio.  The user arrives at the shopping mall and
   enters the building.  The white space radio in the smartphone is on,



Probasco, et al.         Expires March 12, 2012                [Page 15]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   and is scanning for a master/AP.  As the user gets near the entrance
   to the shopping mall, the smartphone locates one of the APs in the
   building and connects to it.  The smartphone begins to use this TVWS
   radio for internet access.  This internet access does not count
   against the users cellular data cap (the mall owner is providing the
   internet access) and also the data rates are better than cellular
   data.  As the user walks throughout the mall the smartphone moves
   between coverage of different APs, and the smartphone connects to a
   new AP when the user and smartphone move near it.

   In order to encourage customers to come to the shopping mall, the
   mall owner has a loyalty program where members register, build
   points, and receive coupons and other notices from the shops in the
   mall.  Before installing the internet service in the mall, all
   loyalty program information was mailed to the user, at an address
   which was provided by the user when joining the loyalty program.

   The ISP provider describes to the mall owner how the loyalty program
   can be improved using the internet service provided by the APs in the
   TV white space.  A new app is developed for this loyalty program, and
   promoted to users, asking them to install the app on their
   smartphone.  The app is provisioned with the user's loyalty program
   information.  When the user comes to the shopping mall, the
   smartphone locates the master/AP providing internet service and
   connects to the AP.  The app in the smartphone sees that a radio
   connection to an AP in the TV white space frequency band is now
   active.  The app registers the identity of the AP and forwards this
   to the home server for the loyalty program, using the internet
   connection provided by the AP in the TV white space band.  The
   loyalty program server registers the identity of the user from the
   loyalty program credentials and also the identity of the AP.  Next
   the loyalty program server contacts the TV white space database and
   requests the location of the master/AP having the identity forwarded
   by the app and smartphone.  When the TV white space database replies
   with the location coordinates of the AP, the loyalty program server
   knows the approximate location of the user and smartphone.  With this
   location information, the loyalty program server can now forward
   loyalty program information to the user.  As the user moves through
   the mall, the smartphone connects to different APs.  The process is
   repeated, allowing the loyalty program to delivery current location
   based information to the user.

   1.  The master create a TVWS network as described in use case
       "Hotspot: urban internet connectivity service."

   2.  An application running on the user's slave device (e.g.
       smartphone) determines that a network connection exists in the
       TVWS band.  The identify of the master/AP is recorded by the



Probasco, et al.         Expires March 12, 2012                [Page 16]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


       application and forwarded to a server in the internet cloud.

   3.  The server queries the trusted white space database with the
       master identity provided by the application in the user's
       smartphone.

   4.  The trusted white space database replies to the server with the
       location of the master device.

   5.  The server uses the location of the master/AP to determine the
       approximate location of the user's smartphone.  The server
       provides location-specific service to the user via the
       application running in the smartphone.

4.7.  Rapid deployed network for emergency scenario

   Organizations involved in handling emergency operations often have a
   fully owned and controlled infrastructure, with dedicated spectrum,
   for day to day operation.  However, lessons learned from recent
   disasters show such infrastructures are often highly affected by the
   disaster itself.  To set up a replacement quickly, there is a need
   for fast reallocation of spectrum, where in certain cases spectrum
   can be freed for disaster relief.  To utilize free or freed spectrum
   quickly and reliable, automation of allocation, assignment and
   configuration is needed.  A preferred option is make use of a robust
   protocol, already adopted by radio manufacturers.  This approach does
   in no way imply such organizations for disaster relief must compete
   on spectrum allocation with other white spaces users, but they can.
   A typical network topology would include wireless access links to the
   public Internet or private network, wireless ad hoc network radios
   working independent of a fixed infrastructure and satellite links for
   backup where lack of coverage, overload or outage of wireless access
   links occur.

   The figure below shows an example deployment of this scenario.
















Probasco, et al.         Expires March 12, 2012                [Page 17]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


                              \|/
                               | ad hoc
                               |
                             |-|-------------|
                             | Master node   |       |------------|
     \|/                     | with          |       | Whitespace |
      | ad hoc              /| backhaul link |       | Database   |
      |             /------/ |---------------|       |------------|
   ---|------------/                |      \           /
   | Master node   |                |       |      (--/--)
   | without       |                |       ------(       )
   | backhaul link |                |  Wireless  / Private \
   ----------------\                |    Access (   net or  )
                    \                |            \ Internet )
                     \    \|/        |      -------(        /\
                      \    | ad hoc  |      |       (------)  \---------
                       \   |         |      /                 | Other  |
                        \--|-------------  /Satellite         | nodes  |
                        | Master node   | / Link              ----------
                        | with          |/
                        | backhaul link |
                        -----------------


       Figure 6: Rapid deployed network with partly connected nodes

   In the ad hoc network, all nodes are master nodes in a way that they
   allocate RF channels from the white space database.  However, the
   backhaul link may not be available to all nodes, such as depicted for
   the left node in the figure.  To handle RF channel allocation for
   such nodes, a master node with a backhaul link relays or proxies the
   database query for them.  So master nodes without a backhaul link
   follow the procedure as defined for clients.  The ad hoc network
   radios utilise the provided RF channels.  Details on forming and
   maintenance of the ad hoc network, including repair of segmented
   networks caused by segments operating on different RF channels, is
   out of scope of spectrum allocation.


5.  Problem Statement

   The use of white space spectrum is enabled via the capability of a
   device to query a database and obtain information about the
   availability of spectrum for use at a given location.  The databases
   are reachable via the Internet and the devices querying these
   databases are expected to have some form of Internet connectivity,
   directly or indirectly.  The databases may be country specific since
   the available spectrum and regulations may vary, but the fundamental



Probasco, et al.         Expires March 12, 2012                [Page 18]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   operation of the protocol should be country independent.

   An example high-level architecture of the devices and white space
   databases is shown in the figure below:



           -----------
           |WS Device|                              ------------
           |Lat: X   |\           .---.    /--------|Database X|
           |Long: Y  | \         (     )  /         ------------
           -----------  \-------/       \/               o
                              ( Internet )               o
           -----------  /------(        )\               o
           |WS Device| /         (_____)  \         ------------
           |Lat: X   |/                    \--------|Database Y|
           |Long: Y  |                              ------------
           -----------


    Figure 7: High level view of the White space database architecture

   In the figure above, note that there could be multiple databases
   serving white space devices.  The databases are country specific
   since the regulations and available spectrum may vary.  In some
   countries, for example, the U.S., the regulator has determined that
   multiple, competing databases may provide service to White Space
   Devices.

   A messaging interface between the white space devices and the
   database is required for operating a network using the white space
   spectrum.  The following sections discuss various aspects of such an
   interface and the need for a standard.  Other aspects of a solution
   including provisioning the database, and calculating protected
   contours are considered out of scope of the initial effort, as there
   are significant differences between countries and spectrum bands.

5.1.  Global applicability

   The use of TV white space spectrum is currently approved by the FCC
   in the United States.  However regulatory bodies in other countries
   are also considering similar use of available spectrum.  The
   principles of cognitive radio usage for such spectrum is generally
   the same.  Some of the regulatory details may vary on a country
   specific basis.  However the need for devices that intend to use the
   spectrum to communicate with a database remains a common feature.
   The database provides a known, specifiable Protection Contour for the
   primary user, not dependent on the characteristics of the White Space



Probasco, et al.         Expires March 12, 2012                [Page 19]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   Device or it's ability to sense the primary use.  It also provides a
   way to specify a schedule of use, because some primary users (for
   example, wireless microphones) only operate in limited time slots.

   Devices need to be able to query a database, directly or indirectly
   over the public Internet and/or private IP networks prior to
   operating in available spectrum.  Information about available
   spectrum, schedule, power, etc. are provided by the database as a
   response to the query from a device.  The messaging interface needs
   to be:

   1.  Radio/air interface agnostic - The radio/air interface technology
       used by the white space device in available spectrum can be
       802.11af, 802.16, 802.22, LTE etc.  However the messaging
       interface between the white space device and the database should
       be agnostic to the air interface while being cognizant of the
       characteristics of various air-interface technologies and the
       need to include relevant attributes in the query to the database.

   2.  Spectrum agnostic - the spectrum used by primary and secondary
       users varies by country.  Some spectrum has an explicit notion of
       a "channel" a defined swath of spectrum within a band that has
       some assigned identifier.  Other spectrum bands may be subject to
       white space sharing, but only have actual frequency low/high
       parameters to define protected entity use.  The protocol should
       be able to be used in any spectrum band where white space sharing
       is permitted.

   3.  Globally applicable - A common messaging interface between white
       space devices and databases will enable the use of such spectrum
       for various purposes on a global basis.  Devices can operate in
       any country where such spectrum is available and a common
       interface ensures uniformity in implementations and deployment.
       Since the White Space device must know it's geospatial location
       to do a query, it is possible to determine which database, and
       which rules, are applicable, even though they are country
       specific.

   4.  Address regulatory requirements - Each country will likely have
       regulations that are unique to that country.  The messaging
       interface needs to be flexible to accommodate the specific needs
       of a regulatory body in the country where the white space device
       is operating and connecting to the relevant database.








Probasco, et al.         Expires March 12, 2012                [Page 20]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


5.2.  Database discovery

   Another aspect of the problem space is the need to discover the
   database.  A white space device needs to find the relevant database
   to query based on its current location or for another location.
   Since the spectrum and databases are country specific, the device
   will need to discover the relevant database.  The device needs to
   obtain the IP address of the specific database to which it can send
   queries in addition to registering itself for operation and using the
   available spectrum.

5.3.  Protocol

   A protocol that enables a white space device to query a database to
   obtain information about available channels is needed.  A device may
   be required to register with the database with some credentials prior
   to being allowed to query.  The requirements for such a protocol are
   specified in this document.

5.4.  Data model definition

   The contents of the queries and response need to be specified.  A
   data model is required which enables the white space device to query
   the database while including all the relevant information such as
   geolocation, radio technology, power characteristics, etc. which may
   be country and spectrum and regulatory dependent.  All databases are
   able to interpret the data model and respond to the queries using the
   same data model that is understood by all devices.

   Use of XML for specifying a data model is an attractive option.  The
   intent is to evaluate the best option that meets the need for use
   between white space devices and databases.


6.  Requirements

   This section is the placeholder for the requirements derived from the
   use cases.


7.  IANA Considerations

   This document has no requests to IANA.


8.  Security Considerations

   The messaging interface between the white space device and the



Probasco, et al.         Expires March 12, 2012                [Page 21]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   database needs to be secured.  Both the queries and the responses
   need to be delivered securely.  The device must be certain it is
   talking to a bona fide database authoritative for the location and
   spectrum band the device operates on.  The database may need to
   restrict interactions to devices that it has some prior relationship
   with, or may be restricted from providing service to devices that are
   not authorized in some manner.

   As the device will query with it's location, the location must be
   protected against eavesdropping.  Some regulations include personally
   identifiable information as required elements of registration and/or
   query and must similarly be protected.

   All communications between the device and the database will require
   integrity protection.

   Man-in-the-middle attacks could modify the content of a response
   which can cause problems for other networks or devices operating at a
   given location.  Interference as well as total loss of service could
   result from malicious information being delivered to a white space
   device.


9.  Summary and Conclusion

   Wireless spectrum is a scarce resource.  As the demand for spectrum
   grows, there is a need to more efficiently utilize the available and
   allocated spectrum.  Cognitive radio technologies enable the
   efficient usage of spectrum via means such as sensing or by querying
   a database to determine available spectrum at a given location for
   secondary use.  White space is the general term used to refer to the
   bands within the spectrum which is available for secondary use at a
   given location.  In order to use this spectrum a device needs to
   query a database which maintains information about the available
   channels within a band.  A protocol is necessary for communication
   between the devices and databases which would be globally applicable.

   The document describes some examples of the role of the white space
   database in the operation of a radio network and also shows an
   examples of a services provided to the user of a TVWS device.  From
   these use cases requirements are determined.  These requirements are
   to be used as input to the definition of a Protocol to Access White
   Space database (PAWS).


10.  Acknowledgements

   The authors acknowledge Gerald Chouinard and Teco Boot as



Probasco, et al.         Expires March 12, 2012                [Page 22]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   contributors to this document.


11.  References

11.1.  Normative References

   [PAWS-PS]  IETF, "Protocol to Access White Space database: Problem
              statement; https://datatracker.ietf.org/doc/
              draft-patil-paws-problem-stmt/", July 2011.

   [RFC2119]  IETF, "Key words for use in RFCs to Indicate Requirement
              Levels;
              http://www.rfc-editor.org/rfc/pdfrfc/rfc2119.txt.pdf",
              March 1997.

11.2.  Informative References

   [DDR]      Ofcom - Independent regulator and competition authority
              for the UK communications industries, "Digital Dividend
              Review; http://stakeholders.ofcom.org.uk/spectrum/
              project-pages/ddr/".

   [DTV]      "Digital TV Transition; http://www.dtv.gov".

   [ECC Report 159]
              Electronic Communications Committee (ECC) within the
              European Conference of Postal and Telecommunications
              Administrations (CEPT), "TECHNICAL AND OPERATIONAL
              REQUIREMENTS FOR THE POSSIBLE OPERATION OF COGNITIVE RADIO
              SYSTEMS IN THE 'WHITE SPACES' OF THE FREQUENCY BAND 470-
              590 MHZ; http://www.erodocdb.dk/Docs/doc98/official/pdf/
              ECCREP159.PDF", January 2011.

   [FCC Ruling]
              FCC, "Federal Communications Commission, "Unlicensed
              Operation in the TV Broadcast Bands;
              http://edocket.access.gpo.gov/2010/pdf/2010-30184.pdf"",
              December 2010.

   [RFC5222]  IETF, Hardie, T., Netwon, A., Schulzrinne, H., and H.
              Tschofenig, "LoST: A Location-to-Service Translation Proto
              col;http://www.rfc-editor.org/rfc/pdfrfc/rfc5222.txt.pdf",
              August 2008.

   [Spectrum Framework Review]
              Ofcom - Independent regulator and competition authority
              for the UK communications industries, "Spectrum Framework



Probasco, et al.         Expires March 12, 2012                [Page 23]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


              Review;
              http://stakeholders.ofcom.org.uk/consultations/sfr/",
              February 2005.

   [TV Whitespace Tutorial Intro]
              IEEE 802 Executive Committee Study Group on TV White
              Spaces, "TV Whitespace Tutorial Intro; http://
              grouper.ieee.org/groups/802/802_tutorials/2009-03/
              2009-03-10%20TV%20Whitespace%20Tutorial%20r0.pdf",
              March 2009.


Authors' Addresses

   Scott Probasco (editor)
   Nokia
   6021 Connection drive
   Irving, TX  75039
   USA

   Email: scott.probasco@nokia.com


   Gabor Bajko
   Nokia
   200 South Mathilda Ave
   Sunnyvale, CA  94086
   USA

   Email: gabor.bajko@nokia.com


   Basavaraj Patil
   Nokia
   6021 Connection drive
   Irving, TX  75039
   USA

   Email: basavaraj.patil@nokia.com












Probasco, et al.         Expires March 12, 2012                [Page 24]

Internet-Draft    PAWS: Problem, uses and requirements    September 2011


   Brian Rosen
   Neustar
   470 Conrad Dr
   Mars, PA  16046
   USA

   Email: brian.rosen@neustar.biz












































Probasco, et al.         Expires March 12, 2012                [Page 25]


Html markup produced by rfcmarkup 1.109, available from https://tools.ietf.org/tools/rfcmarkup/