DESCRIPTION
Title of Invention
WIRELESS COMMUNICATION ROUTING
Technical Field
[0001]
This invention relates to routing of communication in wireless third generation (3G),
networks, and in particular to routing of communications via 3G Femtocells. This invention
also relates to 3G Femtocell deployment in small to medium size enterprises (SMEs).
Background Art
[0002]
Mobile communication systems operate on a cellular basis in which transmission and
receiver base stations coupled to a network provide transmission and reception to user equipment
(UE) such as mobile telephones in each cell in a network. There is usually a single base station
in each cell. The base stations are usually referred to as macro base stations and the cells as
macrocells.
[0003]
Smaller cell sites called picocells have been proposed. These cover a smaller area such
as a complex of buildings. Still smaller cell sites called Femtocells are also proposed. This is
a term used by mobile operators to refer to cell sites of the type which attempt to solve the often
expensive problem of providing complete in-building coverage where macrocells are often
unable to provide adequate coverage due to attenuation and scattering of the radio signal from
the base station.
[0004]
A Femtocell is often referred to as an access point base station. Femtocells are also
known as Home NodeB or Home eNodeB cells. It is a small plug and play device which
communicates with user equipment such as mobile handsets using second generation (2G) or
third generation (3G) transmission reception using wireless cellular networks. It is connected
to the cellular network via a broadband service using either Xdsl or WiMax™ technology. Xdsl
is a family of technologies in which a digital subscriber loop allows broadband communications
over conventional copper telephone lines, and WiMax™, is a wireless Technology defined by the
IEEE (Institute of Electrical and Electronics Engineers) 802.16 standard providing improved
wireless broadband compared to conventional Wi-Fi systems. WiMax is a pending trade
mark application of the WiMax Forum, California, USA and Wi-Fi ™ is a registered trade mark
of the Wi-Fi ™Alliance, California, USA.
[0005]
A Femtocell can optionally incorporate the functionality of a broadband router so that a
user has a completely integrated device. The Femtocell should integrate seamlessly with the
core network of the mobile communication system so that it can be remotely managed and
updated.
[0006]
In Europe, one of the common 3G technologies, Universal Mobile Telecommunications
System (UMTS), uses Wideband Code Division Multiple Access (W-CDMA) as the Radio
Access Technology (RAT) to provide wireless communication. However, other RATs such as
Code Division Multiple Access 2000 (CDMA 2000), Time Division Multiple Access
(TD-CDMA), Universal Wireless Consortium (UWC), or Digital European Cordless
Telecommunication (DECT) radio technologies may be used to implement 3-G networks.
[0007]
In this way, Femtocells deployed in SMEs provide the traditional mobile services in the
same way as in the Macro Layer networks from a user's perspective.
Summary of Invention
Technical Problem
[0008]
However, establishing a connection between a UE and a Femtocell currently occupies a
substantial amount of the core network's resources, both in the control signalling plane and in the
user data plane.
Solution to Problem
[0009]
According to a first aspect of the present invention, there is provided a method for
routing communications in a communications network between a first User Equipment (UE)
registered with an access point base station and a second User Equipment, the method
comprising the steps of determining whether the second user equipment is within network
coverage of the access point base station or a further access point base station; and routing the
communication via one or more of the access point base stations in dependence upon the result
of the determination. One or more of the access point base stations may be positioned at least
partially within range of one or more macro base stations.
[0010]
According to a second aspect of the present invention, there is provided an access point
base station for routing communications between a first User Equipment registered with the
access point base station and a second User Equipment, the access point comprising means for
determining whether the second user equipment is within network coverage of the access point
base station or a further access point base station and means for routing the communication via
one or more of the access point base stations wherein the communication is routed via one or
more of the access point base stations in dependence upon the result of the determination. One
or more of the access point base stations may be positioned at least partially within range of one
or more macro base stations.
[0011]
According to a further aspect of the present invention, there is provided a
computer-readable medium which when executed on a computer executes the method according
to the first aspect of the present invention.
Advantageous Effects of Invention
[0012]
Aspects of the invention enable a Femtocell to provide private branch exchange
(BPX)-like internal circuit switched call services between UE's without using the core network's
resources. By an internal call, we mean any communication between one UE and another UE,
which may be a voice, video call or other communication such as a text message, when both
parties i.e. UE's are within the Femtocell SME network coverage.
[0013]
This has the advantage of making the core network's resources more readily available
for other UE's when Femtocells are not available as an alternative to macrocells. Providing
internal circuit switched call services also allows for services to be provided free or at lower rate
of charge.
[0014]
Aspects of the invention achieve this by modifying the Circuit Switched (CS) call
establishment procedure. The modification does not impose any change on the mobile
communications standards or to network components. All changes are reflected in the
Femtocells or Closed Subscriber Group (CSG) cells instead. Aspects of the invention may
comprise a local database that is manipulated by each CSG cell to track and update a UE status
when it roves in, stays in and roves out the Femtocell coverage. A phone number to
International Mobile Subscriber Identity (IMSI) or/and Temporary Mobile Station Identifier
(TMSI) mapping table may also be provided whereby the CSG cell determines whether or not
the ongoing call establishment is an internal CS call without the CS core network involvement.
[0015]
Aspects of the invention remove or minimise the involvement of the operator's core
network in the internal CS call establishment, without any modification to conventional mobile
handsets and the core network components in order for the Femtocell SME network to be
interoperable with the existing operator's core network and the subscribers' mobile handsets.
Brief Description of Drawings
[0016]
[Fig- 1]
Fig. 1 is a schematic diagram showing a Femtocell connected to a network and in
communication with user equipment.
[Fig- 2]
Fig. 2 is a schematic diagram showing a macro cell with a base station and a number of
Femtocells present within it.
[Fig. 3]
Fig. 3 is a schematic diagram showing the overall signalling flow of CS call
establishment.
[Fig- 4]
Fig. 4 is a schematic diagram showing the overall signalling flow for internal CS call
establishment.
Description of Embodiments
[0017]
Exemplary embodiments of the invention will now be described in detail, by way of
example only, with reference to the accompanying drawings.
[0018]
In Fig. 1 there is shown a Femtocell 2 which is coupled to a network at 4. This is
usually a hard wired connection such as a local area network (LAN). The Femtocell comprises
a Femtocell gateway 6 and an access point 8 coupled by a Broadband connection 10. The
access point has coupled to it a transmitter-receiver or transceiver 12 which transmits and
receives signals over a short distance to user equipment positioned within range. The user
equipment may be for example, a mobile phone 14 or a data card 16 attached to a laptop 18.
User equipment which comes within range of a Femtocell access point may communicate
directly with that access point if it is authorised to do so, and does this in preference to
communication with a macro cell within which it is positioned.
[0019]
In Fig. 2, a schematic diagram of a macro cell 20 is shown. This has a base station 22
which transmits and receives signals from user equipment positioned within it. Further
positioned within the macro cell are a plurality of Femtocells 2. These may comprise clusters
of Femtocells 2 as may be required in a large office building or individual cells which may be
used in private homes for example. In practice, in a city many thousands of Femtocells could
be present within a single macro cell.
[0020]
When a piece of user equipment such as a handset 14 or data card 16 establishes a
connection with a 3G Macro cell, it goes through a circuit switched (CS) call establishment
signalling procedure. The overall signalling procedure of CS call establishment is shown in Fig.
3. This is the case where two UEs, UEl and UE2 are camped on cells, CSG Cell 1 and CSG
Cell 2, belonging to different radio network controllers (RNCs).
[0021]
After moving into Radio Resource Control (RRC) connected state via RRC Connection
Establishment phase (1), the calling party UEl sends an RRC Initial Direct Transfer message,
which packs Mobility Management Connection Management (MM CM) Service Request, to the
RNCl (2). The RNCl then forwards MM CM Service Request to the CS Core via Signalling
Connection Control Part/Radio Access Network Application Part (SCCP/RANAP). RANAP
Initial UE message triggers the SCCP to establish Iu-CS signalling connection to the circuit
switched (CS) Core for transferring the RANAP messages. During the Iu-CS signalling
connection establishment (Iu-CS is the interface between the mobile switching centre (MSC) and
Radio Network Station (RNS)), the CS Core sends the RNCl the UEl 's IMSI as seen in message
(4).
[0022]
After the Security Mode procedure (5) that enables integrity protection and ciphering,
the UEl-to-CS Core signalling connection has been established. It consists of an RRC
connection (Signalling Radio Bearers or SRBs) and the Iu-CS signalling connection.
[0023]
The UEl then initiates Call Control (CC) Setup via RRC Uplink Direct Transfer and
RANAP Direct Transfer. CC Setup specifies the called party UE2 phone number and number
type (6). The CS Core responds by returning a Call Proceeding to acknowledge that it has now
received all the information to establish the CS call connection (7).
[0024]
The CS Core analyses the UE2 phone number and maps it by using the number type and
numbering plan to the UE2's permanent identity, i.e. International Mobile Subscriber Identity
(IMSI). The CS Core then sends RANAP Paging (8) to the RNC2 that covers the location area,
within which the UE2 registered its location area (assuming a single RNC per Location Area
network planning). The RANAP Paging addresses the UE2 using a mandatory IMSI and an
optional TMSI. The RRC Paging Type 1 preferably specifies TMSI, for confidentiality, or
IMSI to address the UE2.
[0025]
After RRC Connection Establishment (9), the UE2 sends the Radio Resource
Management (RRM) Paging Response to the CS Core ( 0). Likewise, the RANAP Initial UE
message triggers the SCCP to establish Iu-CS signalling connection to the CS Core for
transferring the RANAP messages (11). During the Iu-CS signalling connection establishment,
the CS Core sends to the RNC2 the UE2's IMSI (12). Procedures (16) and (17) are used to
establish user plane Radio Access Bearer (RAB). The CS call establishment is completed by
the CC Alerting (18, 19), CC Connect (20) and CC Connect Acknowledge (21) messages.
[0026]
The signalling procedure according to exemplary embodiments of the invention is
shown in Fig. 4. The CSG cells referred to relate to the latest specification of 3G Femtocells as
currently being developed. That is to say, a CSG cell may be a Femtocell.
[0027]
When a UE originates CS call within the Femtocell SME coverage, to check whether or
not the called party is a UE within the Femtocell SME coverage as well, the called party number
must become available. However the calling party UE does not send the called party number
until RRC: Uplink Direct Transfer / CC: Setup (called party number), thus the signalling flow
according to exemplary embodiments of the invention does not change until after sending this
message. By the time when this message is received by the CSG Cell 1, the CS Core has
already set up Iu-CS signalling connection towards the UEl, and is waiting to further complete
CS call connection to it.
[0028]
The CSG Cell 1 by using the called party number resolution mechanism, described in
further detail below, knows that this is an internal CS call attempt. To remove the use of the
operator's network resources, the CGS Cell 1 does not pack CC: Setup in RANAP message and
forward to the CS Core. Instead, it sends CM Service Abort to the CS Core to abort the CS call
establishment that was triggered by MM: CM Service Request, meanwhile it broadcasts LAN:
Paging (IMSI) to all CSG cells of the SME network via the Ethernet LAN that interconnects
these CSG cells to form the SME network. It also sends RRC: Downlink Direct Transfer / CC:
Call Proceeding to the UE1 .
[0029]
After reception of the paging type 1 message, the UE2 initiates RRC Connection
Establishment, and then sends RRM: Paging Response. In the standard signalling procedure,
CSG cell2 forwards this Paging Response to the CS Core, and trigger Iu-CS signalling
connection establishment between the UE2 and the CS Core. In order to remove the
involvement of the operator's network for the internal CS call services, the CSG Cell 2 changes
the signalling flow and directly forwards the Paging Response to the CSG Cell 1. The CSG
Cell 1 then responds by sending LAN: Direct Transfer / CC : Setup (calling party number) to the
CSG Cell 2. Thus, from the UE's point of view, the signalling flow appears to be the same as
standard CS call establishment.
[0030]
The UE-to-UE traffic channel establishment (RAB establishment in 3GPP's term)
comprises two Radio Bearer Setups and LAN Bearer Setup. The Radio Bearer (RB) setup is as
previously described between the UEs and the CSG cells and controlled by two co-ordinated
CSG cells. Exemplary embodiments of the invention comprise a new LAN Bearer setup
functionality which is added onto the CSG cells.
[0031]
After the RAB Establishment, CC: Alerting, CC: Connect and CC: Connect Ack are
transferred sequentially between the UEs and CSG cells, and the two CSG cells forward these
messages via LAN: Direct Transfer. The CS call tear-down procedure is similar, i.e. the two
CSG cells forward the relevant messages via LAN: Direct Transfer.
[0032]
The Iu-CS signalling connection is not maintained for the UE1 and is not established for
UE2 during the internal CS call, the CS Core thinks that the two UEs are in MM-Idle state, and
expects a Periodic Location Updating Request from them. However the two UEs are actually
in Radio Resource Control (RRC) Cell-Dedicated Channel (DCH) state, in which state the
Periodic Location Updating stops. Thus when Periodic Location Updating timer expires in the
CS Core, the CS Core updates the two UEs' state to MM-Detached, and no paging for incoming
PS call can reach them anymore until the call releases and the UEs re-register with the CS Core.
[0033]
This allows free internal CS call services to be provided while remaining interoperable
with conventional mobile handsets and core network components.
[0034]
Exemplary embodiments of the invention do not allow CSG cell to Macro cell handover
when one of the two UEs steps out the SME coverage. However, because the two parties of an
internal CS call are usually stationary or moving in pedestrian speed within an office building,
only CSG cell to CSG cell handovers may occur, and therefore it is not usually necessary to
allow CSG cell to macro cell handover.
[0035]
[Tracking idle User Equipment within Femtocells]
When a UE in the SME coverage originates a CS call to another UE, the CSG cell that
the calling UE camps on has to know whether or not the called UE is within the SME Femtocell
coverage and in Idle state. To be able to do so, the CSG cells track a UE whenever it roves in,
stays and roves out the SME coverage. Each of the CSG cells maintains a local database that
records status of each in-coverage idle UE. The database may take the following form as an
example.
[0036]
Table :An extract of a database stored on a Femtocell or CSG cell with which a calling UE
registered.
[0037]
To keep the database updated, the CSG cells perform the following tasks:
(a). When a UE roves in the SME coverage, it performs standard Location
Updating with the core network via one of the CSG cells since the CSG cells broadcast an
identical and unique Location Area Code (LAC) that is different from the surrounding Macro
cells. The UE performs the Location Updating in the same way as via any Macro cell. To be
able to receive the UE's IMSI, the CSG cell, via which the standard Location Updating is being
performed, inserts Identity Request as well. The CSG cell records the IMSI or/and allocated
TMSI of the UE and broadcasts them to all the CSG cells of the SME network via the Ethernet
LAN that interconnects these CSG cells to form the SME network. The broadcast may be
implemented at Internet Protocol (IP) layer or more efficiently at Medium Access Control
(MAC) layer.
(b). When a UE roves out of the SME coverage, it performs standard Location
Updating via the surrounding Macro cell that it thinks is the most appropriate by the cell
reselection criteria. Thus none of the CSG cells receive a Periodic Location Updating Request
from this UE, and the Periodic Location Updating timer expires in the CSG cell, via which the
UE performed the Location Updating last time. The timeout triggers this CSG cell to remove
the UE from its local database and broadcast the removal to all the CSG cells via the Ethernet
LAN. A Periodic Location Updating via another CSG cell (cell reselection within the SME
happened) activates the timer in that CGS cell meanwhile deactivate the timer in the CGS cell,
via which the Location Updating was performed last time.
(c). The UE staying within the SME coverage performs the Periodic Location
Updating to notify the core network that it is still in that location and in Idle state. The UE
performs the Periodic Location Updating in the same way as via any Macro cell. The CSG cell,
via which the Periodic Location Updating is being performed, broadcasts this event to all the
CSG cells via the Ethernet LAN in order for them to update their local database. This CSG cell
then resets its Periodic Location Updating timer.
[0038]
Operations (a), (b) and (c) ensure integrity of the database across the CSG cells in the
SME network, and enable direct paging from the calling CSG cell without the core network
involvement.
[0039]
[Mobile Subscriber Integrated Services Digital Network Number (MSISDN) - International
Mobile Subscriber Identity (IMSI) - Temporary Mobile Station Identifier (TMSI) mapping table]
In order for the calling CSG cell to convert the called party phone number to the called
party IMSI, and further be able to look-up the local database to check if the called UE is within
the SME coverage and in Idle state, each internal call enabled (Universal Subscriber Identity
Module) USIM identity (IMSI) and associated telephone number (Mobile Subscriber Integrated
Services Digital Network (ISDN) or MSISDN) are one-to-one mapped in a table that can be
configured and managed by the SME network administrator. The table may take the following
form as an example.
[0040]
Table 2:An extract of a second database stored on a Femtocell or CSG cell with which a calling
UE is registered.
[0041]
Each CSG cell of the SME network has a copy of the table. Addition, deletion or
modification of any item in the mapping table will trigger the update of all the copes in the CSG
cells.
[0042]
When a UE originates a CS call within the SME coverage, the CSG cell serving the UE
looks up the mapping table to find out the corresponding IMSI of the called UE, then looks up
the local database to check whether the called UE is within the SME coverage and in Idle state or
not. If the database does not contain the called UE's record, that means it is not an internal CS
call and the standard signalling procedure will be followed, otherwise the proposed signalling
procedure will be followed to obtain a free internal CS call services.
[0043]
[Functionality on CSG cells]
The Femtocell access technology does not follow the UMTS Macro network
architecture. Instead it is tailored to better use of Internet backhauling (transmitting data to a
network backbone or main internet network). The CSG cells contain all Node B functionalities,
most RNC functionalities and some core network functionalities. To provide the free internal
CS call services, exemplary embodiments of the invention may include the following
functionality in CSG cells:
(1) Subset of the CS core's Call Control protocol. To minimise the CS core
functionality that the CSG cells have to be added for the internal CS call establishment, the CSG
calls can always select the default UMTS speech codec in Speech Codec Selection.
(2) LAN transparent transfer protocol for transferring CC signalling between the
CSG cells. It is functionally similar to RANAP over Iu-CS. It can be designed to be a TCP
based upper layer protocol.
(3) User plane protocol for voice / video traffic transferring over Ethernet between
the CSG cells. It can be tailored from an existing Internet Engineering Task Force protocol.
[0044]
While the invention has been particularly shown and described with reference to
exemplary embodiments thereof, the invention is not limited to these embodiments. It will be
understood by those of ordinary skill in the art that various changes in form and details may be
made therein without departing from the spirit and scope of the present invention as defined by
the claims.
[0045]
It will be appreciated that embodiments of the invention may be implemented both in
computer software (program) as well as directly in chips and the like directly integrated into an
access point or femtocell. The software (program) may be provided on a carrier medium such
as a CD ROM (Compact Disc Read-Only Memory) or may be transmitted over a network. The
program is the one for causing a CPU (Central Processing Unit) or the like to execute the
signaling procedure shown in Fig. 4.
[0046]
The program can be stored and provided to a computer using any type of non-transitory
computer readable media. Non-transitory computer readable media include any type of
tangible storage media. Examples of non-transitory computer readable media include magnetic
storage media (such as floppy disks, magnetic tapes, hard disk drives, etc.), optical magnetic
storage media (e.g. magneto-optical disks), CD-ROM, CD-R (compact disc recordable),
CD-R/W (compact disc rewritable), and semiconductor memories (such as mask ROM, PROM
(programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random access memory),
etc.). The program may be provided to a computer using any type of transitory computer
readable media. Examples of transitory computer readable media include electric signals,
optical signals, and electromagnetic waves. Transitory computer readable media can provide
the program to a computer via a wired communication line (e.g. electric wires, and optical fibers)
or a wireless communication line.
[0047]
This application is based upon and claims the benefit of priority from United Kingdom
patent application No. 1001623.6, filed on February 1, 2010, the disclosure of which is
incorporated herein in its entirety by reference.
Reference Signs List
[0048]
2 FEMTOCELL
4 NETWORK
6 FEMTOCELL GATEWAY
8 ACCESS POINT
10 BROADBAND CONNECTION
12 TRANSMITTER-RECEIVER (TRANSCEIVER)
14 MOBILE PHONE (HANDSET)
16 DATACARD
18 LAPTOP
20 MACRO CELL
22 BASE STATION
CLAIMS
[Claim 1]
Amethod for routing communications in a communications network between a first
User Equipment (UE) registered with an access point base station and a second User Equipment,
the access point base station positioned at least partially within range of one or more macro base
stations, the method comprising the steps of:
determining whether the second user equipment is within network coverage of the
access point base station or a further access point base station positioned at least partially within
range of one or more macro base stations; and
routing the communication via one or more of the access point base stations in
dependence upon the result of the determination.
[Claim 2]
The method according to claim 1 in which the step of deteraiining whether the second
user equipment is within coverage of the access point base station or further base station
comprises searching using a UE identifier, in particular an International Mobile Subscriber
Identity (IMSI), a look-up table for an identifier indicating whether the second UE is within
coverage of the access point base station or further base station.
[Claim 3]
The method according to claim 2 in which the look-up table comprises one or more UE
identifiers, each identifier associated with an identifier indicating whether the UE is within
coverage of the access point base station or further base station.
[Claim 4]
The method according to any one of claims 1 to 3 in which the access point base station
with which the first UE is registered determines whether the second UE is within network
coverage of the access point base station or the further access point base station.
[Claim 5]
The method according to any one of claims 1 to 4 further comprising the step of the
access point base station with which the first UE is registered searching a second look-up table
for an International Mobile Subscriber Identity of the second UE, using a telephone number of
the second UE.
[Claim 6]
The method according to claim 5 wherein the second look-up table comprises one or
more International Mobile Subscriber Identities of one or more UEs, each identity associated
with a telephone number of a UE.
[Claim 7]
The method according to any one of claims 2 to 6 in which one or more of the first or
second look-up tables is stored on the access point base station with which the first UE is
registered.
[Claim 8
The method according to any one of claims 2 to 7 further comprising the step of each
access point base station broadcasting to all other access point base stations data updating the
first look-up table.
[Claim 9]
The method according to claim 8 in which the data comprises one or more of data
indicative of when a UE moves into the coverage of an access point base station, data indicative
of when moves out of coverage of an access point base station, and data indicative that a UE
remains within coverage of an access point base station.
[Claim 10]
The method according to any one of claims 1 to 9 further comprising the step of the
access point base station with which the first UE is registered sending a call management service
abort message to a circuit switched core network via one of the macro base stations to prevent
call establishment via the macro base station.
[Claim 11]
The method according to any one of claims 1 to 10 in which the access point base
station with which the first UE is registered broadcasts a local area network paging International
Mobile Subscriber Identity message to all access points.
[Claim 12]
The method according to claim 11 in which the identity message is broadcast via a local
area network, in particular an Ethernet local area network.
[Claim 13]
The method according to any one of claims 1 to 12 in which the communication is
routed via a further local area network or the local area network, in particular an Ethernet local
area network.
[Claim 14]
The method according to any one of claims 1 to 13 further comprising the step of the
second UE sending a local are network paging International Mobile Subscriber Identity message
to the access point base station with which the first UE is registered via the access point base
station with which the second user equipment is registered.
[Claim 15]
The method according to any one of claims 1 to 14 further comprising the step of the
access point base station with which the first UE is registered sending to the access point base
station with which the second UE is registered a local area network call set up message including
the identifier of the first UE.
[Claim 16]
The method according to any one of claims 1 to 15 in which the communication is only
routed via one or more of the access point base stations if it is determined that the second UE is
within range of one of the access point base stations.
[Claim 17]
The method according to any one of claims 1 to 16 in which the access point base
stations have a shorter range than the macro base stations.
[Claim 18]
An access point base station for routing communications between a first User
Equipment registered with the access point base station and a second User Equipment, the access
point base station positioned at least partially within range of one or more macro base stations,
the access point comprising:
means for determining whether the second user equipment is within network coverage
of the access point base station or a further access point base station positioned at least partially
within range of one or more macro base stations; and
means for routing the communication via one or more of the access point base stations;
wherein the communication is routed via one or more of the access point base stations in
dependence upon the result of the determination.
[Claim 19]
The access point base station according to claim 18 further comprising storage means
for storing a look up-table.
[Claim 20]
The access point base station according to claim 19 further comprising searching means
for searching the look-up table.
[Claim 21]
The access point base station according to claim 20 in which the searching means is
arranged to search using a UE identifier, in particular an International Mobile Subscriber Identity
(IMSI), the look-up table for an identifier indicating whether the second UE is within coverage
of the access point base station or further base station.
[Claim 22]
The access point base station according to any one of claims 19 to 2 1 in which the
look-up table comprises one or more UE identifiers, each identifier associated with an identifier
indicating whether the UE is within coverage of the access point base station or further base
station.
[Claim 23]
The access point base station according to any one of claims 18 to 22 further comprising
further storage means for storing a second look up-table.
[Claim 24]
The access point base station according to claim 23 further comprising further searching
means for searching the second look-up table.
[Claim 25]
The access point base station according to claim 24 in which the searching means is
arranged to search the second look-up table for an International Mobile Subscriber Identity of the
second UE, using a telephone number of the second UE.
[Claim 26]
The access point base station according to claim 25 in which the second look-up table
comprises one or more International Mobile Subscriber Identities of one or more UEs, each
identity associated with a telephone number of a UE.
[Claim 27]
The access point base station according to any one of claims 18 to 26 further comprising
broadcasting means for broadcasting to all other access point base stations data updating the first
look-up table.
[Claim 28]
The access point base station according to claim 27 in which the updated data comprises
one or more of data indicative of when a data indicative of when a UE moves into the coverage
of an access point base station, data indicative of when a UE moves out of coverage of an access
point base station, and data indicative that a UE remains within coverage of an access point base
station.
[Claim 29]
The access point base station according to any one of claims 18 to 28 further comprising
a local area network, in particular an Ethernet local are network for routing the communications.
[Claim 30]
Amethod for routing communications in a communications network between a first
User Equipment (UE) registered with an access point base station and a second User Equipment,
the method comprising the steps of:
detennining whether the second user equipment is within network coverage of the
access point base station or a further access point base station; and
routing the communication via one or more of the access point base stations in
dependence upon the result of the determination.
[Claim 31]
A computer-readable medium which when executed on a computer executes the method
of any one of claims 1 to 17.
[Claim 32]
An access point base station substantially as herein described with reference to the
accompanying drawings.
[Claim 33]
A method for routing communications substantially as herein described with reference
to the accompanying drawings.