U.S. patent application number 12/752908 was filed with the patent office on 2010-09-09 for automatic base station configuration.
This patent application is currently assigned to UBIQUISYS LIMITED. Invention is credited to Richard Byrne, William Franks, Peter Keevill.
Application Number | 20100227645 12/752908 |
Document ID | / |
Family ID | 34983951 |
Filed Date | 2010-09-09 |
United States Patent
Application |
20100227645 |
Kind Code |
A1 |
Keevill; Peter ; et
al. |
September 9, 2010 |
AUTOMATIC BASE STATION CONFIGURATION
Abstract
A basestation in a cellular communications network is configured
such that it has a different Location Area Identification from
other local basestations in the cellular network. This has the
effect that a Location Area Update procedure is performed when a
mobile device wishes to camp onto that basestation. The basestation
is able to configure itself automatically, to ensure that its
Location Area Identification differs from other local
basestations.
Inventors: |
Keevill; Peter; (Bath,
GB) ; Franks; William; (Wiltshire, GB) ;
Byrne; Richard; (Berkshire, GB) |
Correspondence
Address: |
Weaver Austin Villeneuve & Sampson LLP
P.O. BOX 70250
OAKLAND
CA
94612-0250
US
|
Assignee: |
UBIQUISYS LIMITED
Wiltshire
GB
|
Family ID: |
34983951 |
Appl. No.: |
12/752908 |
Filed: |
April 1, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11664360 |
Mar 29, 2007 |
|
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PCT/GB06/02824 |
Jul 28, 2006 |
|
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12752908 |
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Current U.S.
Class: |
455/561 ;
726/4 |
Current CPC
Class: |
H04W 92/045 20130101;
H04W 84/045 20130101; H04W 88/08 20130101; H04W 92/12 20130101;
H04W 28/08 20130101; H04W 48/08 20130101; H04W 60/00 20130101; H04L
63/0471 20130101; H04W 88/10 20130101; H04W 88/16 20130101; H04W
92/02 20130101; H04W 84/22 20130101; H04W 24/02 20130101; H04L
12/5692 20130101 |
Class at
Publication: |
455/561 ;
726/4 |
International
Class: |
H04B 1/38 20060101
H04B001/38; H04L 9/32 20060101 H04L009/32 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 1, 2005 |
GB |
0515888.6 |
May 30, 2006 |
GB |
0610650.4 |
Claims
1. A method of restricting access to a basestation in a cellular
wireless communications network, the method comprising: maintaining
in said basestation a list of authorized devices; and when an
unauthorized device camps onto the basestation, sending a "Location
Area Not Allowed" message to said unauthorized device.
2. A method as claimed in claim 1, comprising sending said
"Location Area Not Allowed" message to said unauthorized device
only when said unauthorized device camps repeatedly onto the
basestation.
3. A method as claimed in claim 2, comprising sending said
"Location Area Not Allowed" message to said unauthorized device
only when said unauthorized device camps onto the basestation for a
second time within a predetermined time period.
4. A method as claimed in claim 1, comprising sending said
"Location Area Not Allowed" message to said unauthorized device
only after checking that the unauthorized device is not authorized
to access a different basestation having the same Location Area
Identification.
5. A basestation for a cellular wireless communications network,
wherein the basestation comprises a memory for maintaining a list
of authorized devices; and wherein, when an unauthorized device
camps onto the basestation, the basestation is adapted to send a
"Location Area Not Allowed" message to said unauthorized
device.
6. A basestation as claimed in claim 5, wherein the basestation is
adapted to send said "Location Area Not Allowed" message to said
unauthorized device only when said unauthorized device camps
repeatedly onto the basestation.
7. A basestation as claimed in claim 6, wherein the basestation is
adapted to send said "Location Area Not Allowed" message to said
unauthorized device only when said unauthorized device camps onto
the basestation for a second time within a predetermined time
period.
8. A basestation as claimed in claim 5, wherein the basestation is
adapted to send said "Location Area Not Allowed" message to said
unauthorized device only after checking that the unauthorized
device is not authorized to access a different basestation having
the same Location Area Identification.
9. A basestation for a cellular wireless communications network,
wherein the basestation is adapted to provide coverage in a
coverage area within a macro network, and wherein the basestation
is identified by a PLMN that is defined by an Equivalent PLMN
within the macro network.
10. A basestation as claimed in claim 9, wherein the basestation
has a different Location Area Identification from other local
basestations of said network.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 11/664,360, filed Mar. 29, 2007, which is a National Phase U.S.
filing under 35 U.S.C. .sctn.371 of International Application No.
PCT/GB06/02824, filed Jul. 28, 2006, which claims priority from GB
Application No. 0515888.6, filed Aug. 1, 2005, and GB Application
No. 0610650.4, filed May 30, 2006, each of which is incorporated
herein by reference in their entirety for all purposes. The present
application claims priority to and benefit of each of these
applications.
BACKGROUND
[0002] This invention relates to a cellular basestation for a
wireless communications network, and in particular to a basestation
for a cellular communications network, that can conveniently be
used to provide a cellular service, for example within a home or
office. More specifically, the invention relates to a basestation
that is able to configure itself for operation within the cellular
wireless communications network.
[0003] Conventional cellular wireless communications networks, for
example, based on the GSM or UMTS standards, make use of a number
of identifiers in the radio network, and these identifiers allow
the network to be subdivided into a number of sections, normally
based around geography. The purpose of the identifiers is to ease
the management of the network and improve efficiency in some
aspects, such as organization of paging.
[0004] For example, the document ETSI TS 123 003--V3.4.0, section
4, "Identification of location areas and base stations" describes
the use of three identifiers, namely the Location Area
Identification (LAI), the Routing Area Identification (RAI), and
the Service Area Identification (SAI).
[0005] Typically, many tens or hundreds of basestations share a
common controller, either a Base Station Controller (BSC) in the
case of GSM, or a Radio Network Controller (RNC) in the case of
UMTS. These basestations would usually be included in a single
Location Area and would therefore have the same LAI.
[0006] Routing Area and Service Area Identifications can each be
used to subdivide a Location Area into smaller units, in order to
break very large paging groups down into smaller, more manageable
units.
[0007] In addition, basestations are uniquely identified by a Cell
Identity (Cl).
[0008] All of these parameters are specified from a centralized
network control function as part of the commissioning process for
the cellular radio network, and are typically static, or at least
are changed very infrequently.
[0009] The present invention relates primarily to a small
basestation that is located on a customer's premises, and can be
put into service by the customer as he wishes. In such a situation,
it is potentially very time-consuming for the network operator to
have to configure the Identifications for each such
basestation.
[0010] According to a first aspect of the present invention, there
is provided a method of allocating a Location Area Identification
to a basestation in a cellular wireless Communications network, the
method comprising:
[0011] in the basestation itself, configuring the basestation such
that it has a different Location Area Identification from other
local basestations of said network.
[0012] According to a second aspect of the present invention, there
is provided a basestation, for use in a cellular wireless
communications network, wherein the basestation is adapted to
configure itself such that it has a different Location Area
Identification from other local basestations of said network.
[0013] According to a third aspect of the present invention, there
is provided a management node for a basestation in a cellular
wireless communications network, the management node being adapted
to receive a request for a list of available Location Area
Identifications from a management node of the network, and to
provide a list of available Location Area Identifications in
response thereto.
[0014] According to a fourth aspect of the present invention, there
is provided a method of identifying a Location Area in a cellular
communications network, the method comprising, in a basestation of
said network:
[0015] including a first Location Area Identification in radio
transmissions from said basestation, said first Location Area
Identification being selected from a first set of Location Area
Identifications;
[0016] including a second Location Area Identification in messages
sent to a core network of said cellular communications network,
said second Location Area Identification being selected from a
second set of Location Area Identifications.
[0017] According to a fifth aspect of the present invention, there
is provided a method of restricting access to a basestation in a
cellular wireless communications network, the method
comprising:
[0018] maintaining in said basestation a list of authorized
devices; and
[0019] when an unauthorized device camps onto the basestation,
sending a "Location Area Not Allowed" message to said unauthorized
device.
[0020] For a better understanding of the present invention, and to
show how it may be put into effect, reference will now be made, by
way of example, to the accompanying drawings, in which:
[0021] FIG. 1 is a block schematic diagram of a system
incorporating a basestation in accordance with the present
invention.
[0022] FIG. 2 is a flow chart, illustrating a first procedure in
accordance with the invention.
[0023] FIG. 3 is a flow chart, illustrating a second procedure in
accordance with the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0024] FIG. 1 is a block schematic diagram, illustrating a system
architecture. A mobile network operator (MNO) owns and operates a
wireless communications network, including a radio access network
10, including a network of cellular basestations (not shown), and a
core network 20, having a connection into the fixed telephone
network. These are generally conventional, except as described
below.
[0025] A mobile phone 30, when roaming in the territory covered by
the wireless communications network, is able to establish a
wireless connection with one of the cellular basestations, in order
to communicate with other telephones in the fixed telephone
network, or with other mobile phones, which have established their
own wireless connections with a cellular basestation, and hence
with the fixed telephone network.
[0026] In accordance with the present invention, there is provided,
for example within a home or office 40 or in another location where
additional wireless coverage is required, a further basestation, or
access point, 50. This access point 50 is provided for use by the
owner of the premises where it is located, but is integrated into
the wireless communications network. That is, the access point
shares the part of the radio frequency spectrum allocated to that
wireless communications network, by having allocated to it, either
permanently or temporarily, some of the group of channels. This
group of channels is thus shared with other basestations, which may
serve macrocells, microcells, picocells, or even "femtocells", in
the public, wide area network. As a result, the mobile phone 30 can
roam from the access point 50 to another basestation when leaving
the immediate vicinity of the access point 50, or can roam to the
access point 50 from another basestation when returning to the
immediate vicinity of the access point 50.
[0027] The access point 50 therefore acts as a basestation within
the relevant wireless communications network. For example, it can
allow an entirely conventional and unmodified mobile phone 30 or
other user device to establish a connection for voice and/or data
services using GSM/GPRS and/or UMTS air interfaces. Of course, the
access point 50 can be enabled to establish connections with the
mobile phone 30 using the standard air interface of any suitable
cellular wireless communications system.
[0028] The access point 50 has a connection for an Ethernet Local
Area Network (LAN) 42, within the home or office 40. As shown in
FIG. 1, the access point 50 can connect over the Ethernet LAN 42 to
one or more local PCs or servers 44.
[0029] The access point 50 can connect over the Ethernet LAN 42 to
an IP gateway device 60. The IP gateway device 60 provides an IP
connection over an IP network 70, for example the internet, to the
MNO network either via a Digital Subscriber Line (DSL) or via other
IP transport methods such as a digital multimedia Cable network.
Thus, the existing IP connection from the home or office can be
used to provide backhaul from the access point 50. Flexible
interfacing to the operator's network 20 can be provided via
connections to either the MNO Core Network or Radio Access Network,
using the SIP Gateway or UMA UNC respectively. This approach
enables low-cost transport of data and voice using
Voice-over-Internet Protocol (VoIP) techniques.
[0030] The connection from the IP gateway 60 over the IP network 70
into the MNO Radio Access Network 10 is provided by a UMA
Unlicensed Network Controller (UNC) 12, which has been standardised
by 3GPP as a Generic Access Network Controller (GANC). Other
non-standardised solutions to interface to the Radio Access Network
10 could also be employed as an alternative approach. Direct
connection to the operator's Core Network can be achieved through
use of a SIP Interface between the access point and a suitable
gateway such as a SIP Gateway or an IP Multimedia Subsystem.
[0031] In this illustrated embodiment, the DSL or cable IP gateway
device 60 includes provision for connection of a POTS telephone or
fax device 62, and audio/video connections for providing IPTV
services to a TV 64. The access point 50 includes a services
environment which allows these facilities to be integrated into the
MNO network, enabling sophisticated new services for users.
[0032] In an alternative implementation of the invention, the
access point 50 can be integrated as a component within the IP
gateway device 60; an internal IP connection then links the
embedded access point component to the router functions within the
IP gateway device. This configuration can potentially provide a
lower overall cost and is convenient for operators looking to
provide gateway units which unify data, fixed voice, multimedia and
mobile services.
[0033] Thus, while the mobile phone 30 is within the home or office
40, or otherwise within the coverage area of the access point 50,
it can connect into the MNO network in the same way as via any
other basestation in the cellular wireless communications
network.
[0034] FIG. 1 also shows a network server 72 connected to the IP
network 70. As will be appreciated, where the IP network 70 is the
internet, a very large number of servers and other devices are
connected to the network. As will be described in more detail
below, the user of the mobile phone 30 can access such devices by
means of the access point 50.
[0035] FIG. 1 also shows a management system 74, connected to the
IP network 70. The management system 74 is provided by the mobile
network operator for managing the operation of the access point 50,
including controlling the available services.
[0036] For example, as mentioned above, and as described in more
detail below, a user of the mobile phone 30 can establish a
connection through the access point 50 over the Ethernet LAN 42 to
one or more local PCs or servers 44, or through the IP gateway
device 60 to another device connected thereto, or through the IP
gateway device 60 to a network server 72 connected to the IP
network 70. These connections can be established without passing
traffic over the core network 20 of the wireless communications
network. The management system 74 is able to define the devices, or
the IP addresses, with which such connections can be established.
Then, these connections can be established with only a restricted
number of devices or IP addresses, if desired by the mobile network
operator.
[0037] Also, the management system 74 is able to specify a set of
channels (which may be defined by frequencies, time slots, and/or
spreading codes, depending on the particular cellular wireless
communications system) allocated for the access point 50 to use.
These channels may be allocated semi-permanently, or may be changed
regularly, depending on the requirements of the network as a whole.
The access point will select an optimal channel configuration for
use, from the set specified by the management system.
[0038] In normal macrocell operation, a UE, such as the mobile
phone 30, registers onto a cell by means of a Location Registration
(LR) if the selected or reselected cell has a different Location
Area or PLMN (Public Land Mobile Network) identity. In the case of
cells with a common Location Area Identifier, the UE can simply
camp on to any cell with the common LAI without giving any
indication to the network that it has done so.
[0039] The network configuration for the access point 50 is
somewhat different from a conventional radio network. For example,
the access point 50 includes BSC/RNC functionality, and may be
independent of any other radio network control function. As a
result, the typical use of Location Area Identifications (LAIs) and
Routing Area Identifications (RAIs) does not apply.
[0040] Furthermore the access point 50 requires the mobile phone 30
to identify itself as it roams in from the macrocell network.
Identifying the access point 50 with a LAI which is different from
the overlying macro layer (and from any other local access point)
triggers a Location Update Procedure in the mobile phone 30, which
automatically informs the mobile phone 30 and the network that it
has moved to coverage by the access point 50.
[0041] Therefore, the access point 50 will configure itself to have
a different Location Area (and therefore Routing Area) to the
macro-network, so that a Location Registration procedure will
always be necessary. An IMSI Attach may also be performed during
the Location Registration procedure.
[0042] It is envisaged that the network may include a relatively
large number of access points such as the access point 50, and
moreover that the distribution of active access points may change
relatively frequently. Thus, configuring the access point LAIs from
a central control scheme would be time-consuming.
[0043] The access point 50 therefore uses an automatic
self-configuration scheme. FIG. 2 is a flow chart, illustrating
this automatic self-configuration scheme.
[0044] At step 200, the access point 50 starts its installation
procedure, for example when first powered up. In one embodiment,
the rules for the self-configuration are specified centrally in the
management system 74, and are downloaded to the access point 50 at
step 202 during installation.
[0045] In one embodiment, the Mobile Network Operator reserves a
group of LAIs for use by access points such as the access point 50.
The Location Area Code (LAC) of the Location Area Identification
(LAI), as defined in the document ETSI TS 123 003--V3.4.0, section
4.1, has 16 bits, and thus there are about 65,000, 216, possible
identifiers. A typical conventional network might use less than
1000 of these. Thus, in accordance with this embodiment of the
invention, the Mobile Network Operator reserves a list of LAIs for
use by access points such as the access point 50. This list may for
example include 100-10,000 LAIs.
[0046] At step 204, this list of available LAIs is downloaded to
the access point 50.
[0047] As part of the general installation procedure, the access
point 50 performs an RF scan process. During this process, at step
206 of the procedure shown in FIG. 2, the access point 50 monitors
the Broadcast Channel (BCH) of transmissions from surrounding
Node-B's and access points in accordance with the present
invention. The LAI and RAI information is included in the BCH
transmission, and so the installing access point 50 will be able to
deduce which of LAIs from the list of available LAIs have been
taken by surrounding access points.
[0048] Then, in step 208, the access point 50 selects its own LAI
using a random choice of the remaining available LAIs.
[0049] The key issue is that the LAIs for all of the access points
observed from any single mobile are unique. Depending on the
transmit power of the access points, amongst other things, this may
mean all of the access points in a radius of less than 200 m. It is
acceptable for more distant access points to repeat LAIs.
[0050] The access point 50 can then enter service, using the
selected LAI.
[0051] At step 210, it is determined whether to repeat the
selection procedure. The procedure may be repeated at each
installation and at each power-up, but, in a typical case, the
automatically configured LAI will be retained unless there is a
significant change in the surrounding cell environment such as a
relocation of the access point itself.
[0052] FIG. 3 is a flow chart, illustrating an alternative
automatic self-configuration scheme in accordance with an
embodiment of the invention.
[0053] At step 300, the access point 50 starts its installation
procedure, for example when first powered up. In one embodiment,
the rules for the self-configuration are specified centrally in the
management system 74, and are downloaded to the access point 50 at
step 302 during installation.
[0054] In this embodiment, the Mobile Network Operator reserves a
group of LAIs for use by access points such as the access point 50.
The Location Area Code (LAC) of the Location Area Identification
(LAI), as defined in the document ETSI TS 123 003--V3.4.0, section
4.1, has 16 bits, and thus there are about 65,000, 216, possible
identifiers. A typical conventional network might use less than
1000 of these. Thus, in accordance with this embodiment of the
invention, the Mobile Network Operator reserves a list of LAIs for
use by access points such as the access point 50. This list may for
example include about 10,000 LAIs.
[0055] At step 304, the access point 50 sends a message to the
management system 74, requesting a LAI from the list of available
LAIs. The management system 74 responds with an LAI that is
available for use by the access point 50.
[0056] In order to assist with this, it may be required that each
new access point customer should record their address details, and
these could be recorded in the management system 74. By using these
address details, for example using post code information in the UK,
the management system 74 can make an initial allocation of an LAI
identifier to each new customer that is highly probable to be
unique within that particular locality.
[0057] The access point may confirm, by observation of information
transmitted by surrounding access points on their respective
broadcast channels, that the received LAI is not in use in any
observable local access points. If the received LAI is not found to
be in use in any observable local access points, that LAI can be
configured; if the access point detects another local access point
with the same LAI, it can request the management system for another
LAI.
[0058] The access point 50 can then enter service, using the
selected LAI. Since the list of available LAIs contains so many
LAIs, there is only a low probability that two local access points
will select the same LAI. In that event, the collision may be
corrected by later observation.
[0059] Thus, when the access point 50 performs an RF scan process,
at step 306 of the procedure shown in FIG. 3, the access point 50
monitors the Broadcast Channel (BCH) of transmissions from
surrounding Node-B's and access points in accordance with the
present invention. The LAI and RAI information is included in the
BCH transmission, and so the installing access point 50 will be
able to deduce whether its own LAI is shared with the any of the
surrounding access points.
[0060] If so, in step 308, the access point 50 selects a new LAI,
for example by requesting a new LAI from the management system 74,
as described above.
[0061] Thus, it is possible to ensure that, for almost all mobiles
and for almost all of the time, the LAIs for all of the access
points observed from any single mobile are unique. In any event, it
will be noted that the access point 50 can be connected directly to
the core network using a network interfacing scheme, such as via
SIP or IMS, in which the LAI identifiers are not required for
locating users and routing paging messages. Rather, IP address
information is recorded and used instead. Thus, it would be
permissible in these scenarios for the access point 50 to reselect
its LAI at power-up or during the next scheduled RF scan, if it
detected a common LAI used by another local access point.
[0062] At step 310, it is determined whether to repeat the
selection procedure. The procedure may be repeated at each
installation and at each power-up but, as noted above with
reference to step 210, it is most likely to remain static until a
major change in the surrounding cellular environment is
observed.
[0063] Thus, there are described methods for selecting a new LAI in
the access point 50. It will be noted that the LAI simply has to be
different from that of the surrounding cells in order to force the
Location Update. It is not necessary for the LAI to remain static.
Moreover, when a LAI is allocated to the access point, a new RAI is
also allocated.
[0064] The use of distinct LAI identifiers has benefits in
scenarios where the access to the access point 50 is to be
restricted to specific users. That is, the access point 50 can be
configured such that only certain specified devices (UEs) are
allowed to connect to the network through that access point.
Typically, an access point on the premises of a particular customer
will be configured such that only the specified devices (UEs) owned
by that customer are allowed to connect to the network through that
access point. That is, only those UEs whose IMSIs are defined
within the management system and subsequently downloaded to the
access point, are allowed to camp on that access point.
[0065] The access point 50 may carry the PLMN identifier of the MNO
macro network (which will typically be specified as the Home PLMN
in the SIM card of the UE(s) of the relevant customer), or it may
be identified by a PLMN which is different to the macro network but
is defined as an "Equivalent PLMN" within the macro network. In the
case where the access point 50 has the same PLMN as the macro
network or an Equivalent PLMN to the macro network, any macro
network UE will camp onto the access point if it determines it to
be the strongest signal. In the case of an access point 50
configured such that only certain specified devices (UEs) are
allowed to connect to the network through that access point, the
access point will respond to a non-specified device camping on by
issuing a standard GSM/UMTS rejection message to cause the
offending UE to reselect another cell, typically the macro cell it
has just roamed out of.
[0066] If the offending UE camps back onto the access point cell
within a few minutes of this rejection, the access point can use an
alternative rejection message "Location Area Not Allowed" which
causes the LAI identifier of the specific access point` to be added
to a list of banned cells maintained by the UE. Once the LAI is
included in the banned list, the UE will not attempt to camp on
again. The banned list is maintained until the UE is turned off or
reset.
[0067] In this situation, it is advantageous if the LAI of the
access point is not used in any other access point.
[0068] On the other hand, if the number of LAIs allocated to access
points such as the access point 50 is very much smaller than the
number of access points, there exists a risk that the LAI in the
banned list of the offending UE might also be the LAI of a
different access point cell that the user may legitimately access.
In this scenario, the access point 50 may, before using the
"Location Area Not Allowed" rejection message, request the
management system to cross check that the offending IMSI is not
associated with an access point, or, if it is, that the LAI from
which the user is about to be banned is not the same as the LAI(s)
associated with the access point(s) that the user is allowed to
access.
[0069] As mentioned above, a typical conventional network may use
only a relatively small number (for example less than 100, or even
less than 100) of the available LAIs, even when the network is
large. In that case, it may present some complications for the MNO
if a large set of LAI/RAI identifiers is available for use by
access points such as the access point 50.
[0070] If so, this set of LAI/RAI identifiers can be collapsed into
a smaller set. This may be done in a centralised location or
through a translation mapping operation within the access point
itself. The access point includes a sophisticated protocol stack
which includes Non-Access Stratum functions typically found in the
circuit and packet core of a mobile network. The access point can
use these functions to terminate mobility management (MM) and GPRS
mobility management (GMM) signalling from the UE. Optionally, the
access point can intercept these messages and modify them before
passing them on to the MNO network. Thus, the LAI/RAI identifiers
included in the messages received from the UE (and derived from the
LAI/RAI identifier transmitted by the access point over the
GSM/UMTS air interface) can be replaced in messages passed onto the
MNO network by an alternative LAI/RAI identifier to suit the
convenience of the operator.
[0071] For example, even though several thousand LAI's may be used
by all of those access points such as the access point 50 in the
network, there could be a much smaller number (for example only
three) of LAIs which are carried in signalling exchanges from the
UEs to the core network. As an example, one LAI could be used for
access point users within their own premises, one could be used for
nominated guests of access point users, and one could be used for
other users who have roamed onto access points which have capacity
available for non-authorised users. The three LAIs in this example
might be used to convey tariff information to the MNO network
billing system.
[0072] There is thus described a system in which a basestation is
configured such that it has a different Location Area
Identification from other local basestations in the cellular
network.
* * * * *