GEOPRIV M. Thomson
Internet-Draft J. Winterbottom
Intended status: Standards Track Andrew Corporation
Expires: January 9, 2011 July 8, 2010
Location Measurements for IEEE 802.16e Devices
draft-thomson-geopriv-wimax-measurements-04
Abstract
IEEE 802.16e defines means for true mobility within an 802.16
wireless network. Determining an accurate location for 802.16e
devices requires information on radio parameters. A format is
defined for location-related measurement data that can be provided by
an 802.16e device. This measurement data can be used by a Location
Information Server (LIS) to more accurately determine the location of
the device. A separate measurement used for identifying WiMAX
session-related parameters is also provided.
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 January 9, 2011.
Copyright Notice
Copyright (c) 2010 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
Thomson & Winterbottom Expires January 9, 2011 [Page 1]
Internet-Draft Location Measurements for 802.16e July 2010
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 used in this document . . . . . . . . . . . . . . 4
3. 802.16e Radio Measurement Data . . . . . . . . . . . . . . . . 5
3.1. Measurement Request Parameters . . . . . . . . . . . . . . 7
4. WiMAX Session-Related Measurements . . . . . . . . . . . . . . 8
5. 802.16e Measurement Schema . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
7.1. URN Sub-Namespace Registration for
urn:ietf:params:xml:ns:held:lm:802.16e . . . . . . . . . . 14
7.2. XML Schema Registration for 802.16e Measurement Schema . . 14
8. Normative References . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
Thomson & Winterbottom Expires January 9, 2011 [Page 2]
Internet-Draft Location Measurements for 802.16e July 2010
1. Introduction
Determining the location of a device in an IEEE 802.16e [IEEE.80216E]
mobile wireless network requires information from the device to
improve the accuracy of the final result. Radio timing information
provided by the device can enable the calculation of a more accurate
location estimate by a Location Information Server (LIS).
This document describes a standard format for 802.16e measurement
data that is based on radio measurements made of base stations near
the device.
Thomson & Winterbottom Expires January 9, 2011 [Page 3]
Internet-Draft Location Measurements for 802.16e July 2010
2. Conventions used in this document
This document builds on [I-D.ietf-geopriv-held-measurements] and
consequently uses the same set of terminology. Terminology from
[IEEE.80216E] is used where appropriate.
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 [RFC2119].
Thomson & Winterbottom Expires January 9, 2011 [Page 4]
Internet-Draft Location Measurements for 802.16e July 2010
3. 802.16e Radio Measurement Data
A subscriber station (SS) in an 802.16e network is able to observe
radio signals from each base station (BS) in its proximity. By
observing the timing and strength of these signals, a SS is able to
provide a LIS with information that can be used to determine its
location.
The most basic 802.16e measurement indicates the serving BS, as shown
in Figure 1.
civic
Figure 1: HELD Location Request with 802.16e Measurement Data
More measurement information can be provided, including timing
measurement information for additional serving base stations (if fast
base station switching (FBSS) or macro-diversity hand-over (MDHO) are
in progress). Information on neighbouring base stations can be
provided in addition to that for the serving BS.
The set of measurement data is chosen by the SS and the presence of
specific elements will depend on the time the SS has available to
acquire the measurements. The following measurement information may
be provided:
id: (Attribute) The base station identifier for the measured BS.
Note that while this isn't a MAC address, it shares the encoding
defined for the MAC address.
rssi: Receive signal strength indicator, calculated as defined in
[IEEE.80216E]. This value is measured in units of dBm. This
datum optionally includes an RMS error in dB and sample count.
cinr: Carrier inteference to noise ratio (signal to noise),
calculated as defined in [IEEE.80216E]. This value is measured in
units of dB. This datum optionally includes an RMS error and
sample count.
Thomson & Winterbottom Expires January 9, 2011 [Page 5]
Internet-Draft Location Measurements for 802.16e July 2010
rd: Relative delay of the signal from the BS, measured relative to
other base stations. Since this value is relative, it MUST be
included on at least two BS measurements to be of any use. It is
RECOMMENDED that this value be set to "0" for the first BS in the
measured set. This datum optionally includes an RMS error and
sample count.
(V) _
| `- _ t[1]
| `- _ t[2]
| BS1 ` . - - - - - - - - - - (V)
_|`. |
|U| `. t[3] |
|_| `. BS2 |
Target SS `.
(V)
|
|
| BS3
Figure 2: Relative Delay Example
Based on the example in Figure 2, relative delay can be calculated
based on the relative time that signals transmitted simultaneously
(or with known relative times) by base stations can be calculated.
If the time of receipt of the signal from each base station is
t[x] and the relative delay for BS1 is set to zero, the relative
time for each subsequent measured base station is t[x] - t[1].
rtd: Round trip delay of the signal from the SS to the BS and back.
This measurement datum is only applicable for each serving BS.
This value is measured in seconds. This datum optionally includes
an RMS error and sample count.
The "rmsError" attribute for signal to noise and received signal
strength MAY be calculated using the continuous weighted average
method described in [IEEE.80216E]. Values of "alpha_AVG" and "k" are
selected by the SS.
The XML format described in this document provides a greater range of
values than the Scanning Results Report ("MOB_SCN-REP") or the
Channel measurement Report Response ("REP-RSP") message. This allows
for the reporting of measurements in a manner less constrained by
encoding. A greater range of values does not necessarily imply
anything about the uncertainty in those measurements; the RMS error
is used to indicate the magnitude of any error.
Thomson & Winterbottom Expires January 9, 2011 [Page 6]
Internet-Draft Location Measurements for 802.16e July 2010
3.1. Measurement Request Parameters
A request that does not contain sufficient measurement data can
result in an error response. [I-D.ietf-geopriv-held-measurements]
defines a measurement request that indicates what parameters might be
necessary to complete the request. These parameters might also be
present in a response that includes an indication that the requested
location quality [I-D.thomson-geopriv-location-quality] was not
provided.
The elements present in a radio measurement are all optional. In
order for a Device to know which of these is requested, the
"parameter" element is defined for radio measurement data. This
identifies each requested element using a qualified name.
The following example shows a HELD error response that indicates that
RSSI and CINR measurement would aid in fulfilling the request.
Insufficient measurement data
w16e:rssi
w16e:cinr
Figure 3
Thomson & Winterbottom Expires January 9, 2011 [Page 7]
Internet-Draft Location Measurements for 802.16e July 2010
4. WiMAX Session-Related Measurements
In Worldwide Interoperability for Microwave Access (WiMAX) networks
[WiMAX.LBS], an SS might have a particular access network designated
as a "home network". In some configurations the network is designed
in such a way that the SS only has access to a location server in the
home network, known as a home location server, or hLS. However, a
server in the current (visited) access network - the vLS - could be
the only server that is capable of communicating with the access
network to determine the location of the SS. In this case the hLS
provides WiMAX session information to the vLS, giving the vLS the
information necessary to identify a session and generate location
information.
Figure 4 shows an example measurement that contains information
regarding a session. This contains the session identifier that is
assigned by the anchor authenticator. The Network Access Identifier
(NAI) [RFC4282] of the device and the address of the anchor
authenticator is included.
19abd9e9f923978f80310d
user.206417@example.realm
f-301.aa.example.com
Figure 4
Session parameters are used to identify a particular network
attachment session:
sessionID: A temporary identifier given to a particular session.
This value is a binary value that is expressed in hexadecimal.
nai: The NAI [RFC4282] used by the device to gain network
authorization.
anchor: The domain name of the anchor authenticator in the visited
network. Optionally, this includes an attribute that indicates an
IP address in addition to the domain name.
The formal grammar for NAI [RFC4282] permits invalid UTF-8, which
cannot be expressed using XML. Therefore, this lexical
representation of NAI permits escaping. Non-unicode characters (and
any other character) are expressed using a backslash ('\') followed
by two hexadecimal digits representing the value of a single octet.
Thomson & Winterbottom Expires January 9, 2011 [Page 8]
Internet-Draft Location Measurements for 802.16e July 2010
The value-space representation of an NAI is the sequence of octets
that is produced from the concatenation of UTF-8 encoded sequences of
unescaped characters and octets derived from escaped components.
This sequence MUST conform to the constraints in [RFC4282].
Thomson & Winterbottom Expires January 9, 2011 [Page 9]
Internet-Draft Location Measurements for 802.16e July 2010
5. 802.16e Measurement Schema
Note: The pattern for NAI has extra whitespace added to conform to
formatting restrictions. The actual value does not contain
whitespace.
This document defines a location-related measurement format
for 802.16e mobile wireless devices.
Thomson & Winterbottom Expires January 9, 2011 [Page 10]
Internet-Draft Location Measurements for 802.16e July 2010
Thomson & Winterbottom Expires January 9, 2011 [Page 11]
Internet-Draft Location Measurements for 802.16e July 2010
Thomson & Winterbottom Expires January 9, 2011 [Page 12]
Internet-Draft Location Measurements for 802.16e July 2010
6. Security Considerations
The considerations of [I-D.ietf-geopriv-held-measurements] apply.
The receiver of 802.16e measurement information requires knowledge of
the location of base stations to make effective use of the
information.
NAI is used as identification information for a device. The
connection of this information with other session parameters provides
a potential link between identity and location. In addition, unless
care is taken to verify this information, this datum could be
exploited by an attacker to gain access to another user's location
information. See the privacy and security considerations of
[I-D.ietf-geopriv-held-identity-extensions] for details on using
identity parameters.
Thomson & Winterbottom Expires January 9, 2011 [Page 13]
Internet-Draft Location Measurements for 802.16e July 2010
7. IANA Considerations
7.1. URN Sub-Namespace Registration for
urn:ietf:params:xml:ns:held:lm:802.16e
This section registers a new XML namespace,
"urn:ietf:params:xml:ns:held:lm:802.16e", following the guidelines in
[RFC3688].
URI: urn:ietf:params:xml:ns:held:lm
Registrant Contact: IETF, GEOPRIV working group,
(geopriv@ietf.org), Martin Thomson (martin.thomson@andrew.com).
XML:
BEGIN
802.16e Measurements
Namespace for 802.16e Measurements
urn:ietf:params:xml:ns:held:lm:802.16e
[[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX
with the RFC number for this specification.]]
See RFCXXXX.
END
7.2. XML Schema Registration for 802.16e Measurement Schema
This section registers an XML schema following the guidelines in
[RFC3688].
URI: urn:ietf:params:xml:schema:held:lm:802.16e
Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org),
Martin Thomson (martin.thomson@andrew.com).
Schema: The XML for this schema can be found in Section 5 of this
document.
Thomson & Winterbottom Expires January 9, 2011 [Page 14]
Internet-Draft Location Measurements for 802.16e July 2010
8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The
Network Access Identifier", RFC 4282, December 2005.
[I-D.ietf-geopriv-held-measurements]
Thomson, M. and J. Winterbottom, "Using Device-provided
Location-Related Measurements in Location Configuration
Protocols", draft-ietf-geopriv-held-measurements-00 (work
in progress), July 2010.
[I-D.ietf-geopriv-held-identity-extensions]
Winterbottom, J., Thomson, M., Tschofenig, H., and R.
Barnes, "Use of Device Identity in HTTP-Enabled Location
Delivery (HELD)",
draft-ietf-geopriv-held-identity-extensions-04 (work in
progress), June 2010.
[I-D.thomson-geopriv-location-quality]
Thomson, M. and J. Winterbottom, "Specifying Location
Quality Requirements in Location Protocols",
draft-thomson-geopriv-location-quality-05 (work in
progress), January 2010.
[IEEE.80216E]
IEEE, "Air Interface for Fixed and Mobile Broadband
Wireless Access Systems; Physical and Medium Access
Control Layers for Combined Fixed and Mobile Operation in
Licensed Bands", Std 802.16E, February 2006.
[WiMAX.LBS]
WiMAX Forum, "WiMAX Network Protocols and Architecture for
Location Based Services", Network Release 1.5 1.0.0 Draft,
November 2008.
Thomson & Winterbottom Expires January 9, 2011 [Page 15]
Internet-Draft Location Measurements for 802.16e July 2010
Authors' Addresses
Martin Thomson
Andrew Corporation
Andrew Building (39)
Wollongong University Campus
Northfields Avenue
Wollongong, NSW 2522
AU
Email: martin.thomson@andrew.com
James Winterbottom
Andrew Corporation
Andrew Building (39)
Wollongong University Campus
Northfields Avenue
Wollongong, NSW 2522
AU
Email: james.winterbottom@andrew.com
Thomson & Winterbottom Expires January 9, 2011 [Page 16]