In mid-April, the IESG requested external review of the draft charter
for a proposed working group to focus on development of a "Protocol to
Access White Space Databases" (paws). Based on discussions within the
IESG, the draft charter has undergone significant revision. As a
courtesy, the revised charter is being provided for informational
purposes. Please send any comments on this revised charter to the IESG
mailing list (iesg@ietf.org) by Wednesday, June 8, 2011.
Protocol to Access White Space database (paws)
------------------------------------------------
Current Status: Proposed Working Group
Last updated: 2011-06-02
Chairs:
TBD
Applications Area Directors:
Pete Resnick <presnick@qualcomm.com>
Peter Saint-Andre <stpeter@stpeter.im>
Applications Area Advisor:
Peter Saint-Andre <stpeter@stpeter.im>
Mailing lists:
General Discussion: paws@ietf.org
To Subscribe: https://www.ietf.org/mailman/listinfo/paws
Archive: http://www.ietf.org/mail-archive/web/paws/
Description of Working Group:
Background
Radio spectrum is a limited resource. National and international
bodies assign different frequencies for specific uses, and in
most cases license the rights to use these frequencies. Locally
unused spectrum is commonly called "white space" and may be made
available to other services on a basis of non-interference with
the primary user of the frequencies concerned (if any). This
technique can help "unlock" existing spectrum, for example to
enable the wireless communications industry to provide more
services over frequencies associated with unused television
channels. An obvious requirement is that white space uses must
not interfere with the primary use of the spectrum. This is
achieved through spatial and/or temporal separation of the
primary user and whitespace user with due consideration made to
the radio characteristics of the two uses.
Problem Statement
The fundamental problem is enabling a radio device to determine, in
a specific location and at specific time, if any white space is
available for secondary use. There are two parties to such an
interaction:
1. A database containing records about the protected contours (in
space and time) of primary spectrum users. Typically, such databases
will be populated and operated by the appropriate spectrum regulation
bodies in a given locale.
2. A radio device that wishes to query such a database. Typically, the
the nature of the query will depend on the needs of the device.
The contents of white space databases, and the needs of radio devices,
are being defined elsewhere. However, these parties need a protocol
for communication that will enable radio devices to find out what white
space is available at a given time in a given location.
It is expected that white space databases will be reachable via the
Internet, and that radio devices too will have some form of Internet
connectivity, directly or indirectly. Therefore, it is appropriate
to define an Internet-based protocol for querying white space databases
and receiving responses from such databases.
In rough outline, such a protocol would enable a radio device that
knows its location to complete the following tasks:
1. Determine the relevant white space database to query.
2. Connect to the database using a well-defined access method.
3. Provide its geolocation and perhaps other data to the database
using a well-defined wire format for querying the database.
4. Receive in return a list of currently available white space
using a well-defined wire format for returning information.
Once the device learns of the available white space (e.g., in a TV
white space implementation, the list of available channels at that
location), it can then select one of the bands from the list and
begin to transmit and receive on the selected band. If the device's
parameters have changed (e.g., if some amount of time has passed or if
the device has changed location beyond a specified threshold), it might
need to query the database again to determine what white space is still
available.
Objectives
The overall goals of this working group are to:
1. Standardize a mechanism for discovering a white space database.
2. Standardize a method for accessing a white space database.
3. Standardize wire formats to be carried over the database
access method (i.e., formats for queries and responses).
4. Ensure that the discovery mechanism, database access method,
and wire formats have appropriate security levels in place.
By "standardize" is not meant that the working group will necessarily
develop new technologies. In completing its work, the group will:
- Evaluate existing discovery mechanisms to determine if one of
them provides the necessary application features and security
properties (or can be extended to do so) for discovering a
white space database. Examples might include DNS.
- Evaluate existing application-layer transport protocols to
determine if one of them provides the necessary application
features and security properties (or can be extended to do so)
for use as a building block for communication between location-
aware devices and white space databases. If such a method
exists, the group will reuse it; if not, the group will develop
one. Examples might include HTTP.
- Develop a method for querying a white space database. Such
a method will utilize, so far as possible, the features of
the application-layer transport protocol and not re-implement
them in the new protocol. It will include mechanisms to verify
that the requests and responses come from authorized sources,
and that they have not been modified in transit. Examples might
include LDAP.
- Define extensible wire formats for both location-specific queries
and location-specific responses for interaction with radio white
space databases. The group will consider whether existing data
formats can be reused.
The protocol must protect both the channel enablement process and the
privacy of users. Robust privacy and security mechanisms are needed
to prevent: device identity spoofing, modification of device requests,
modification of channel enablement information, impersonation of
registered database services, and unauthorized disclosure of a device's
location. The group will consider whether existing privacy and
security mechanisms can be reused.
The task of defining the structure and contents of the databases
themselves is out of scope. The group will standardize wire formats
for communication between devices and databases, but not the information
models for the databases, since those models are likely to be
country-specific or application-specific. In addition, the particular
data exchanged between a device and a database might depend on the
ranges of radio spectrum that are to be used, the requirements of the
database operators and their governing regulations, and other factors.
Therefore, the database access method and the query/response data
formats that are exchanged using that method need to be designed for
extensibility rather than being tied to any specific spectrum, country,
or phy/mac/air interface. For example, the working group should define
extension points for the database access method and the wire formats
that are used to query a database and respond to queries, so that use
cases other than those currently envisioned can be addressed in the
future if a community of interest wishes to do so. However, the
access method and wire formats will incorporate relevant aspects of
the parameters needed for the currently envisioned use cases to ensure
proper operation.
In accordance with existing IETF processes, the group will communicate
and invite participation with other relevant standards bodies and
groups, and if necessary reuse existing liaison relationships or
request the establishment of new liaison relationships, including but
not limited to IEEE 802.11af and IEEE 802.22. In order to ensure that
it takes into account a broad range of possible use cases and
requirements, the group should also reach out to other potential
"customers" for a white space database access method and consider input
from regulatory entities that are involved in the specification of the
rules for secondary use of spectrum in specific radio bands.
Deliverables
1. A description of the relevant use cases and requirements. This
document shall be Informational. Subject to working group consensus,
draft-probasco-paws-overview-usecases and draft-patil-paws-problem-stmt
might be used as a starting point.
2. A specification of the mechanism for discovering a white space
database, the method for accessing a white space database, and the
wire format for querying and receiving responses from a white space
database. This document shall be Standards Track.
Milestones
Oct 2011 Submit 'Use Cases and Requirements for Accessing a Radio White
Space Database' to the IESG for publication as Informational
Apr 2012 Submit 'Accessing a Radio White Space Database' to the IESG
for publication as Proposed Standard
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