TITLE OF INVENTION
COMMUNICATION SYSTEM
5
TECHNICAL FIELD
The present invention relates to mobile telecommunication networks and to parts thereof,
particularly but not exclusively, networks operating according to the 3rd Generation Partnership
Project (3GPP) standards or equivalents or derivatives thereof. The invention has particular
10 although not exclusive relevance to the exchange of inforrnation elements between home base
stations in these networks.
BACKGROUND ART
Under the 3GPP standards, a NodeB (or an eNB in LTE (i.e. Long Term Evolution)) is
15 the base station module via which mobile devices connect to the core network and which defines
a cell of the network. Home base stations or base station modules (HNB) provide short range 3G
radiofrequency (RF) coverage, and are sometimes referred to as femto access points (FAP).
Where the home base station is operating in accordance with the LTE standards, the HNB is
commonly referred to as an HeNB. Some base stations, sometimes referred to as HNBIHeNB,
20 can operate in accordance with both the 3G and LTE standards, and therefore define a dual mode
femtocell. The HNBIHeNB base station may also sometimes be referred to as a dual mode femto
access point (FAl') or dual FAP.
The HNB or HeNB provides radio coverage (for example, 3G, 4G and/or WiMAX)
within the home, small or medium enterprise, shopping malls, etc. and typically connects to the
25 core network via a suitable residential gateway RG and public or corporate broadband (BB)
access network (for example via an ADSL link to the Internet). The HNB or I-IeNB is given an
IP address by the local network to which it is connected, and the I-INB or HeNB provides this IP
address to the mobile telephone operator network so that it can reserve appropriate resources for
the HNB or HeNB through the broadband access network.
30 During operation in a nor~naol peration luode or nornlal state, the IINB or IIeNB enables
users of a User Equipment (UE) to communicate with other such users via one of a number of
the base stations (eNodeB, eNB) and a core network.
In a connected or activc state or mode, a UE is registered with the network and has an
RRC (Radio Resource Control) connection with a base station, so that the network can identify
2
which cell the UE belongs to and can transn~idt ata to and receive data from the UE. In LTE, in
the active state or mode, the Handover procedure allows UEs to have service continuity while
moving within the Intra LTE system (Intra RAT and Inter Frequency) and towards other RATS
(Radio Access Technologies).
5 A UE also has a power conservation or idle state or mode in which, typically, the UE is
not transmitting or receiving data, and no context about the UE is stored by the base station. In
the idle state, the location of the UE is known only (to the MME (Mobility Management Entity)
in 3GPP) at the granularity of a Tracking Area (TA) comprising a cluster or group of base station
cells. When in the idle state, a UE selects and reselects cells according to the parameters
10 broadcast by the base station in the BCN (Broadcast Channel), with a frequency given by a
Tracking Area Update Timer Value, and the base station is not aware of the cell
selections/reselections made by the UE.
During the normal operation mode, the HNB or HeNB usually periodically broadcasts a
downlink transmission comprising reference signals and system information, for instance both
15 the Pilot and the Broadcast Channels, to signal its presence to UEs. Each HNB or HeNB also
checks if there are any UEs in the idle or connected state in its cell. In order to allow the HNB or
HeNB to perform this check, the periodic Tracking Area Update Timer Value may be sent to the
HNB or HeNB through the Operations and Management (O&M) system. If 110 UE responds by
performing the Tracking Area Update, the ImB or HeNB can assume that there is no idle state
20 UE present in the cell. The HNB or HeNB may also perform a dummy paging for an idle state
UE. If the HNB or HeNB does not receive a paging response from a UE, the HNB or HeNB can
assume that there is no idle state UE present in the cell. If no connected or idle state UE is
present in the cell for certain duration of time (as determined by an Idle Timer), the HNB or
HeNB moves to the energy savingmode, in which it stops all downlink transmissions. However,
25 if an energy saving mode timer expires or if the HNB or HeNB receives a paging or any other
message on its S1 interface or TR069 interface (using protocol messages defined in TR 196 Data
Model from Broad Band Forum) or if the NNB or I-IeNB detects an uplink transmission from a
UE in a neighbouring cell, then the HNB or HeNB moves back to the normal operation mode, in
which it starts downlink transmission again.
30 In dual mode cells, both the baseband and the radiofrequency processing hardwarc blocks
of the HeNB are independent from the baseband and the radiofrequency processing hardware
blocks of the HNB.
However, at least one of the base station niodules of a dual mode FAP may need at least
one information element from the other base station module. Typical but not limiting operating
modes ofa dual FAP in which at least one of the base station modules may need at least one
information element from the other base station module include NMM information element
updating, Handover and Circuit-Switched fallback (CSF13).
NMM information element updating
5 The base station modules may comprise a Network Monitor Mode (NMM) module which
is controlled by an application level software module (sometimes referred to as NMM
Controller) and which is configured to operate in'a Network Monitor Mode to scan and monitor
neighbour cells of RAT such as 2G, 3G, LTE, etc. The scan of the neighbour cells comprises an
identification of the neighbour cells and an update of a Neighbour Cell List which includes
10 identification of the identified neighbour cells. The monitoring of the neighbour cells may
comprise the measure of at least one of Physical Cell Identifier (PCI), a Primary Scrambling
Code (PSC) and a carrier frequency of a neighbour cell.
In a dual FAP, the NMM may be operated by only one of the base station modules, or the
two base station modules may not operate the NMM at the same time. Also, in case the base
15 station module operating the NMM is a HeNB, the base station module may identify more
neighbour cells than the HNB of the dual FAP, by virtue of the Automatic Neighbour Relation
(ANR) procedures.
Therefore the NMM module of the base station module which operated the NMM may
need to send the information elements corresponding to the results of NMM, such as the updated
20 PCI, PSC, carrier frequency or Neighbour Cell List, to the other base station module. In some
examples, the sending of the information elements might be done via a TR-069 Auto
Configuration Server (ACS) over the network.
Circuit-Switched fallback (CSFB)
'The I-IeNB of the dual FAP felies on a packet-only radio access technology (RAT), and
25 not a circuit-switched (CS) technology which is traditionally used for phone calls. The HeNB
may therefore need to perform a Circuit-Switched fallback (CSFB), as defined in 3GPP TS
36.300 - v9.6.0, in order to make or receive calls. During the CSFR, the 1JE changes its RAT
fro111 LTE technology to a 2G (GSM) or 3G (UMTS) technology which supports circuit-switched
services.
30 There are several CSFB options for a Circuit Switch fallback to UMTS or GSM. One of
the CSFB options is a RRC Connection Release with Redirection with Sys Info information
element (IE). In an example, if a HeNB needs to perform a CSFB according to this option, the
HeNB needs the information element Sys lnfo of the I-1NU which will make or receive the call.
Handover
A Handover (1-10) is a procedure which changes the serving cell of a UE in
RRC-CONNECTED from a source base station module to a target base station module.
The source base station module makes a decision about initiating a handover based on a
measurement report from the UE and Radio Resource Management (RRM) information. When a
5 source base station module decides to perform a handover, the source base station module passes
all necessary information elements to the target base station module (e.g. E-RAB attributes and
RRC context), using signalling which comprises a handover request message. In return, the
target base station module prepares the HO by sending all necessary information elements using
signalling which comprises a handover request acknowledge to the source base station module.
10 In a HO, Admission Control (AC) may be performed by the target base station module
dependent on the received information from the source base station module, to increase the
likelihood of a successful HO, if the resources can be granted by target base station module.
However, a source or target base station module can dynamically reselect and change at
least one of a Physical Cell Identifier (PCI), a Primary Scrambling Code (PSC) and a carrier
15 frequency. The other base station module of the dual FAP needs the information elements
corresponding to the updated PCI, PSC, and carrier frequency so that the HO can happen and can
be successful.
Furthermore, the decision about the grant of the resources by a target base station module
may depend on information elements such as target cell parameters which may comprise at least
20 one of a static parameter information element, and a dynamic parameter information element.
The static parameter information element may comprise at least one of a maximum number of
UE that the target base station module is configured to serve (sometinies referred to as
MaxUEsServed), the maximum number of closed subscriber group (CSG) members that the
target base station module is configured to serve (sometimes referred to as MaxCSGMembers),
25 the maximu~i iu mber of no11 CSG members that the target base station module is configured to
serve (sometimes referred to as MaxNonCSGMembers). The dynamic parameter information
element may con~prisea t least one of a current number of CSG UE which are served by the
target base station module, a current nuniber of non CSG IJE which are served by the target base
station module, a congestion status of the target base station module, and a load status of the
30 target base station module.
The exchange of the information elements in the examples above has drawbacks.
In the example of an NMM information element updating or in the example of a
handover, an NMM may not be performed by a base station module to monitor immediately the
reselection and change of at least one of the PCI, PSC and carrier frequency by the other base
5
station module of the dual FAP. The delayed NMM may result in at least one of the base station
not having updated information elements as regards to at least one of the PCI, PSC and carrier
frequency of the other base station module of the dual FAP. Furtheril~ore,t he TI<-069 ACS and
the NMM module may not send immediately updated information elements to at least one of the
5 base station module as regards to the NMM results. The delayed sending of the NMM results
may result in at least one of the base station not having updated information elements as regards
to the Neighbour Cell List, and at least one of the PCI, PSC and carrier frequency of neighbour
base station modules.
A subsequent handover might therefore fail or might not occur because of the non
10 updated information elements. Moreover, if a handover is initiated and fails because the
information elements were not updated, the signalling from the source and target base station
modules was an unnecessary signalling over the communications network which may have been
detrimental to other signalling and was unnecessary energy consumption.
In the example of a CSFB, the ImB of the dual FAP sends the needed Sys Info to the
15 HeNB via the core network, using signalling involving RIM (RAN (Radio Access Network)
Information Management) procedure, as defined in 3GPP TS 36.300 - v 9.6.0. This signalling
may result in increased traffic towards the Core Network which might be detrimental to the
quality of the other traffic to the Core Network and is energy consuming.
20 SUMMARY OF THE INVENTION
Aspects of the present invention address or at least ameliorate the above issue.
According to one aspect, the invention provides a communications apparatus comprising:
a first base station module for providing wireless connectivity to a communications network to
one or more mobile con~municationsd evices within range of the first base station module; a
25 second base station module for providing wireless connectivity to a communications network to
one or more mobile comm~~nicationdse vices within range of the second base station module;
and means for transferring, internally to said communication apparatus, at least one information
element from one of the first and second base station modules to the other one of the first and
second base station n~odules.
30 The transferring means may conlprisc an internal interface for coupling the first base
station module and the second base station module.
At least one of the first and second base station modules may provide at least one
information element to the transferring means, and the transferring means may comprise a
memory to store the provided at least onc information element. The other of the first and second
6
base station modules may retrieve the provided at least one information element from the
memory of the transferring means and/or the transferring means may provide the information
element provided by the at least one of the first and second base station modules to the other of
the first and second base station n~odules.
5 The transferring means may comprise an operation administration maintenance module
comprising a memory.
At least one of the first and second base station modules may provide at least one
information element to the other one of the first and second base station via the interface. At
least one of the first and second base station modules may request at least one information
10 element from the other one of the first and second base station via the interface. The interface
may comprise an interface module which comprises at least one controller module for at least
one of the first and second base station modules.
At least one of the first and second base station modules may provide at least one
information element to the other one of the first and second base station via the interface, in
15 response to a request from a controller module.
According to one aspect, the invention provides a communications apparatus comprising:
a first base station module for providing wireless connectivity to a communications network to
one or more mobile communications devices within range of the first base station module; a
second base station module for providing wireless connectivity to a communications network to
20 one or more mobile communications devices within range of the second base station module;
and means for transferring at least one information element from one of the first and second base
station modules to the other one of the first and second base station modules, wherein said
transferring means comprises: means, provided in said first base station module, for generating
and sending B request identifying at least one required information element to a communication
25 node of said communication network; means, provided in said second base station module, for
receiving said request from said communication node and for sending a response to said request
comprising said requested at least one required information element; and means, provided in said
first base station module, for receiving said response.
The communication node may comprise a node of a core network. The request and the
30 response may comprise messages in accordance with a Self Organizing Network (SON) Transfer
protocol. The messages in accordance with the Self Organizing Network (SON) Transfer
protocol may comprise a SON Information Transfer message, and the at least one information
element may be added to the SON Information Transfer message, as any one of: a SON Transfer
Application Identity information element, or a SON Transfer Request Container information
element, or a SON 'Transfer Response Container information element.
The at least one information element may comprise at least one ofi a configuration of at
least one of the first and second base station modules, a Physical Cell Identifier (PCI), a Primary
Scrambling Code (PSC), a carrier frequency, a static parameter information element, a dynamic
5 parameter information element, System Information, such as UMTS system information, and a
neighbour cell list. The static parameter information element may comprise at least one of: a
maximum number of UE that a base station module is configured to serve (MaxlJEsServed), a
maximum number of closed subscriber group (CSG) members that a base station module is
configured to serve (MaxCSGMembers), a maximum number of non CSG members that a base
10 station module is configured to serve (MaxNonCSGMembers). The dynamic parameter
information element may comprise at least one of: a current number of CSG UE which are being
served by a base station module, a current number of non CSG UE which are being served by a
base station module, and a load or congestion status of a base station module.
The first base station module and the second base station module may be mounted within
15 a common housing. The commuuications apparatus may comprise a dual mode femto access
point. At least one of the first and second base station modules may comprise a HNB and the
other of the first and second base station modules may comprise a I-IeNB.
The transferring means may be configured for transferring, internally to said
communication apparatus said at least one information element or for transferring said at least
20 one information element via a communication node of said communication network external to
said communication apparatus in dependence on the at least one information element being
transferred.
According to one aspect, the invention provides a communications apparatus comprising:
a first base station module for providing wireless connectivity to a communications network to
25 one or more mobile communications devices within range of the first base station module; means
for transferring at least one information element from a second base station module, for
providing wireless connectivity to a communications network to one or more mobile
communications devices within range of the second base station module, to the first base station
module, wherein said transferring means comprises: means, provided in said first base siation
30 module, for generating and sending a request identifying at least one rcquired information
element to a communication node of said communication network; and means, provided in said
first base station module, for receiving a response to said request from the second base station
module, the response comprising said requested at least one required information element.
The invention also provides a system for use in a telecommunications network,
comprising one or more mobile communications devices and a coiniiiunications apparatus
according to some aspects of the invention.
According to one aspect, the invention provides a mobile communications device for use
with a communications apparatus comprising: a first base station module for providing wireless
5 coni~ectivityto a communications network to one or more mobile communications devices
within range of the first base station module; a second base station module for providing wireless
connectivity to a communications network to one or more mobile communications devices
within range of the second base station module; an interface for coupling the first base station
module and the second base station module; wherein at least one of the first and second base
10 station modules is configured to exchange, internally to said communication apparatus, at least
one infor~natione lement with the other one of the first and second base station modules via said
interface, and wherein the mobile communications device is arranged to communicate a
communications network via one of the first and second base station modules of the
communications apparatus.
15 According to one aspect, the invention provides a method, performed in a
telecomrnunications network, for facilitating exchange of at least one information element
between two base station modules of a communications apparatus, the method comprising
exchanging at least one information element, over an internal interface coupling the two base
station modules.
20 According to another aspect, the invention provides a method, performed in a
telecommunications network, for facilitating exchange of at least one information element
between two base station modules of a communications apparatus, the method comprising
exchanging at least one information element via transferring means comprising an operation
administration maintenance module comprising a memory.
25 According to another aspect, the invention provides a method, performed in a
telecoinn~unicationsn etwork, for facilitating exchange of at least one information elelllent
between two base station modules of a communications apparatus, the method comprising
exchanging at least one information elenlent via transferring means for transferring said at least
one information element via a communication node of said comiiiunication network external to
30 said con~n~unicatiaopip~a ratus.
According to one aspect, the invention provides a method, performed in a
telecomn~unicationsn etwork, for facilitating exchange of at least one information element
between two base station modules of the network, the method comprising exchanging at least
one information element via transferring means for transferring said at least one information
elelltent via a com~l~unicationno de of said communication network, wherein the transferring
means: generate and send a request identifying at least one required information element Goill a
first base station module to a communication node of said communication network, receive said
request from said communication node and send from a second base station module a response to
5 said request comprising said requested at least one required information element; and receive
said response in the first base station module.
Aspects of the invention extend to computer program products such as computer readable
storage media having instructions stored thereon which are operable to program a programmable
processor to carry out a method as described in the aspects and possibilities set out above or
10 recited in the claims and/or to program a suitably adapted computer to provide the apparatus
recited in any of the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of example, with reference
15 to the accompanying drawings, in which:
Figure 1 schematically illushates a mobile telecommunication system;
Figures 2a, 2b and 2c show a block diagram illustrating the main components of a base
station, that is a home NodeB communications node in a 3G system;
Figure 3 illustrates schematically the main components of a UE of the telecommunication
20 system of Figure 1;
Figure 4a schematically illustrates an example of an architecture for a dual mode FAP of
the telecom~nunication system of Figure 1;
Figures 4b and 4c schematically illustrate another example of an architecture for a dual
mode FAP of the telecommunication system of Figure 1;
25 Figure 5 is a timing diagram illustrating an exemplary method performed by the
telecon~muuicatioils ystem of Figure 1;
Figure 6 is a diagram illustrating another an exemplary method performed by the
telecommunication system of Figure 1; and
Figure 7 is a diagram illustrating yet another an exemplary method performed by the
30 tclecoin~nui~icatiosyi~st cm of Figurc 1.
EXEMPLARY EMBODIMENTS
Although for efficiency of understanding for those of skill in the art, embodiments and
implementations of the invention will be described in detail in the context of a 3G system
10
(UMTS, LTE), the principles of the invention can be applied to other systeins (such as WiMAX)
in which mobile devices or User Equipment (UE) co~nmunicatew ith one of several base stations
with the corresponding elements of the system changed as required.
Overview
5 Figure 1 schematically illustrates a mobile (cellular) telecommunication system 1 in
which users of User Equipments (UE) such as mobile telephones 3-1 to 3-6 can communicate
with other users via different access nodes. In particular, mobile telephones 3 (or other user
equipment UE) can make connections with the mobile telephone eore network 8 directly via a
Universal Terrestrial Radio Access Network (UTRAN) base station 5-1 and associated Radio
10 Network Controller (RNC) 7 or an evolved IJTRAN (E-UTRAN) base station 5-2. Mobile
telephones 3 can also connect to the mobile telephone core network 8 using a 'home' base
station (IINB) provided in a user's commercial or private residence 9. Each HNB or HeNB 11
(i.e. HNB 1 1 - 1, HeNB 1 1-2, HNBIHeNB 1 1-3 and HNBIHeNB 1 1-4) is coupled, by a residential
gateway 13 and a broadbald access network 15 (conforming to the BroadBand Forum, BBF), to
15 the mobile telephone core telephone network 8.
In the example illustrated in Figure 1, the mobile telephone 3-1 is connected to the core
network 8 via the HNB 11-1; the mobile telephone 3-2 is connected to the core network 8 via
I-IeNB 11-2; the mobile telephone 3-3 is connected to the core network 8 via E-UTRAN base
station 5-2; the mobile telephone 3-4 is connected to the core network 8 via UTRAN base station
20 5-1, the mobile telephone 3-5 is connected to the core network 8 via the dual mode base
HNBIHeNB or dual femto access point 11-3; and the mobile telephone 3-6 is connected to the
core network 8 via the dual mode base HNBII-IeNB or dual FAP 11-4.
In the example of Figure 1, the residential gateways 13 connect to the broadband access
network 15 via an ADSL or cable connection 16 and the I-INBs and NeNBs are programmed
25 with the IP address of a security gateway (not shown) within the eore network 8 so that the
HNBs and HeNBs initially connect to the preprogrammed security gateway. In this
embodiment, the residential gateway 13 of a user's commercial or private residence 9 assigns the
HNB or HeNB 11 a local IP address in the broadband access network 15, which the HNB or
HeNB 11 will use in its communications with the core network 8.
30 Advantageously, the I-INB and IleNB of the dual FAP 11-3, 11-4 is provided with an
information transfer portion 14 for transferring at least one information element from one of the
first and second base station modules to the other one of the first and second base station
modules. The transferring module 14 advantageously allows the exchange of information
elements between the HNB and HeNB of the dual FAP. The I-IeNB and the HNB might use the
information element exchanged via the information transfer portion 14 for its own operation, for
instance for updating information and/or for informing a CSFB or Handover as to whether or not
to transfer to the coexisting HNBIHeNB part of the dual FAP.
Home Base Station
5 Figures 2a, 2b and 2c show block diagrams illustrating the main components of a
different example of a HNB base station part of a dual FAP 11-3, 11-4 in the 3G system 1.
As shown in Figures 2a, 2b and 2c, each exemplary HNB part of the dual FAP comprises
at least a transceiver circuit 21 to transmit signals to and to receive signals from the UEs 3 via
one or more antennae 23 and to transmit signals to and to receive signals from the telephone
10 network via a network interface 25. The transceiver circuit 21 is controlled by a controller 27 in
accordance with software stored in memory 29. The software includes, among other things, an
operating system 3 1, an IPSec module 32, a downlink scheduler 33 to schedule user data packets
to be transmitted by the transceiver circuit 21 in communications with the UEs 3, a resource
allocator 34 to allocate frequency resources for use by the UEs 3 for transmitting their uplink
15 data to the base station. In this example, the software further includes a range determiner 35 to
determine the range of a UE from the base station, a modulation type and coding rate (MCS)
determiner 36 to determine the modulation and coding rate to be used, a modulation type and
coding rate scheme (MCS) identifier 37 to identify to a UE 3 the MCS of a control channel upon
which the base station is attempting to communicate with the UE 3, an HNB-GW
20 communication module 38; an SGSNIMSC comn~unicationm odule 39, a user equipment
communication module 40. The HNB 11 further includes radio resource management functions
provided by a standard Radio Network Controller RNC 41.
As described above each exen~plaryH NB part also of the dual FAP 11- 3, 11- 4 includes a
transfer portion 14 (comprising a transfer module referred to as 14-1 in figure 2a) configured for
25 the exchange of information elements with the HeNB part of the FAP 11-3, 11-4.
The HNB part of Fig. 2a comprises a transfer portion comprising a transfer module 14-1
operable to exchange information with the HeNB part using an external transfer mechanism.
The HNB part of Fig. 2b comprises a transfer portion 14 comprising in internal 'HeNB'
interface 28 for use in exchanging infornlation with the HeNB part using an internal transfer
30 mechanism under the control of an infor~l~atiotrna nsfer conlrol module.
Fig. 2c comprises a transfer portion 14 comprising a shared transfer memory into which
the HeNB part and HNB past may store information and from which the HeNB part and HNB
past may retrieve information relating to the other past.
The operation of each transfer portion 14 is described in more detail later in the section
12
entitled 'Operation'.
It will be appreciated that the HeNB part of the dual FAP 1 1-3 and 1 1-4 shown in Figure
1 may have a similar configuration having corresponding components to any of the exemplary
IINB parts shown in Figures 2a, 2b and 2c (including a transfer module or portion 14 for
5 exchanging information with the HeNB part). The main differences between the HeNB part and
the IINB part include the fact that the HNB-GW comn~unicationm odule 38 is optional and,
instead of an SGSNJMSC communication module 39, there may be an MME communication
module for communicating with an MME. Also, the HeNB do not com~nunicateu sing the
IHNBAP protocol, but using the E-UTRAN protocols such as the Sl AP protocol.
10 User Equipment
Figure 3 illustrates schematically the main components of a UE 3 shown in Figure 1. As
shown in Figure 3, each UE 3 includes a transceiver circuit 71 to transmit signals to and to
receive signals from the base stations 5 or 11 via one or more antennae 73. As shown, the UE 3
also includes a controller 75 to control the operation of the UE 3. The controller 75 is connected
15 to the transceiver circuit 71 and to a user interface having, in this example, a loudspeaker 77, a
microphone 79, a display 81, and a keypad 83. The controller 75 operates in accordance with
software instructions stored within memory 85. As shown, these software instructions include,
among other things, an operating system 87 and a communications module 89 having a decoder
90 to perform decoding on a downlink (DL) control channel.
20 Dual FAP Architectures
Figures 4a, 4b and 4c schematically illustrate different architectures for the dual FAP 11-
3 and 11-4 of Figure 1. The FAP of Fig. 4a comprises an HNB part and an HeNB part
substantially as described with reference to Fig 2a. The FAP of Fig. 4b cotnprises an ICNB part
and an HeNB part substantially as described with reference to Fig 2b. The FAP of Fig. 4c
25 comprises an HNB part and an HeNB part substantially as described with reference to Fig 2c.
Fig 4a schematically illustrates an example of an architecture for the dual FAP 11-3 of
Figure 1, where the dual FAP comprises separate controller modules 27-1 and 27-2, i.e. there is a
controller module 27 for each of the I-INB and the HeNB. In this example, each separate
controller module 27-1 and 27-2 may be considered as part of separate baseband chipset 11-3-1
30 and 11-3-2 respectively.
Fig 4b and 4c schematically illustrate an example of an architecture for the dual FAI' 11-
4 of Figure 1, where the dual FAP co~nprisesa single controller module 27, i.e, there is a single
controller module 27 for both the HNB and the HeNB. In this example, the controller module 27
can be considered as part of a single baseband chipset 11-4-1 for both the IHNB and the HeNB.
13
I11 the case of Figure 4a, the two home base stations (IINB and I-IeNB) of the dual FAP
1 1-3 comprise a transfer portion 14 comprising the transfer module 14-1 and 14-2 respectively.
In the case of Figure 4b, the two home base stations (HNB and HeNB) of the dual FAP 11-4
comprise a transfer portion 14 comprising the internal interface 28 between the IINB and HeNB
5 and the associated interface control 28-1. In the case of Figure 4c, the two home base stations
(IINB and HeNB) of the dual FAP 11-4 comprise a transfer portion 14 comprising the shared
transfer memory into which the HeNB part and HNB part may store information and from which
the HeNB part and HNB part may retrieve information relating to the other part.
In figures 4a, 4b and 4c, the first base station module and the second base station nlodule
10 are mounted within a common housing as shown by arrows 11-3 and 11-4.
Operation
Examples of methods used for transferring at least one information element from one of
the first and second base station modules to the other one of the first and second base station
modules of a dual FAP, will now be described. Although for efficiency of understanding for
15 those skilled in the art, the invention will be described in detail in the context of two home base
stations (HNB and HeNB) of a dual FAP, the principles described herein can be applied to a
multimode FAP comprising more than two home base stations with the corresponding elements
ofthe system changed as required.
In the FAP 11-3 described with reference to Fig 4a and the NNBIHeNB parts described
20 with reference to Fig 2a, the transfer portion 14 for transferring information elements from one
of the first and second base station modules to the other one of the first and second base station
modules is operable to transfer information elements using an external mechanism, for example,
via communication with another communications node 18 such as a Serving GPRS Support
Node (SGSN), elsewhere in the communication network for instance in the core network 8.
25 Specifically, the FAP 11-3 described with reference to Figs. 2a, 4a may employ an
external transfer mechanism as illustrated, in simplified form, in Fig. 5. As seen in Fig. 5 a first
home base station of the FAP 11-3 sends an information element transfer request to request at
least one information element, via its respective transfer module 14-1, 14-2 to an external
cominunication node 18 (in this case an SGSN). The external communication node 18 then
30 transn~itsth e inforn~atione lenlent transfer request sent to the second base station of the FAP 11-
3 where the corresponding transferring module 14-2, 14-1 receives and interprets the request.
The second base station then sends an information element transfer response containing the
requested information element(s), in reply to the original transfer request, via its transfer module
14-2, 14-1 to the external communication node 18. The external com~nunicationn ode 18 then
transn~itsth e infor~natione lement transfer response containing the requested information
elen~ent(st)o the first home base station of the FAP 11-3 where the corresponding transfer
module 14-1, 14-2 of the first base station receives and interprets the information element
transfer response.
5 In this example, the first and second base station modules are advantageously configured
to perform the external transfer using a Self Organizing Network (SON) Transfer protocol as
defined in 3GPP TS 36.413 V10.3.0 and TS 48.018 V10.3.0. In accordance with the SON
transfer protocol, the information ele~nentsw hich may be transferred from one base station
module to another base station module of a dual FAP 11 are added to a SON Information
10 Transfer message, as any one of:
a SON Transfer Application Identity information element, or
a SON Transfer Request Container information element, or
a SON Trallsfer Response Container information element.
In each FAP 11 described with reference to Figs 4b and 4c and the HNBIHeNB parts
15 described with reference to Figs. 2b and 2c, the transfer portion 14 for transferring information
elements from one of the home base station parts to the other one of home base station parts uses
an internal mechanism to transfer the information elements. Both the HeNB and the HNB of the
dual FAP 11 are able to exchange, as shown by arrows 30, and interpret the information
elements transferred by the transferring module or portion 14.
20 The FAP 11 described with reference to Figs. 2b, 4b employs an internal transfer
mechanism as illustrated, in simplified form, in Fig. 6. As described with reference to Fig. 2b,
the transfer portion 14 con~prisesa n internal interface 28 for coupling one home base station part
with the other home base station part.
As seen in Fig. 6, in this example, a first of the home base station parts has, in S1, at least
25 one information element which may be needed by a second coexisting home base station part.
The first home base station part provides, in S2, the at least one infonnation element to the
coexisting second home base station part via the internal interface 28 under the control of the
interface controller module 28-1, in response to an indication that the information elements are
required. The indication may comprise an explicit request from the second home base station
30 part to requcst the information represented by thc information element(s), may comprise an
external impetus fro111 another co~nmunicationn ode to request that the first home base station
part provides the infornlation, or may comprise an internal indication from one of thc modules of
the first home base station part, for example, in response to a predetermined condition being
reached. For example, a congestion status or other load related infor~natione lement(s) may be
provided to the second home base station, by the first honle base station part, in response to an
explicit request from the second base station, or may be provided when a predetermined
congestion threshold has been reached so that the second home base station part can avoid
handing a device over to the first home base station part when insufficient resources are
5 available. In S3 the second home base station receives the infor~natione lement as a result of the
transfer.
The FAP 11 described with reference to Figs. 2c and 4c employs a transfer portion 14
cornprising a shared transfer mert~orya s described previously and a transfer mechanism as
illustrated, in simplified form, in Fig. 7. As seen in Fig. 7, a first of the home base station parts
10 has, in S4, at least one information element which may be needed by a second coexisting home
base station part. The first home base station part stores the information element(s), in S5, in the
shared transfer memory. The second home base station part retrieves, from the shared transfer
memory, in S6 any stored information element required. The shared transfer memory
advantageously forms part of an operation administration maintenance (OAM) module
15 comprising the shared memory.
Advantageously, the provision of the shared transfer memory allows information
elements representing an initial configuration of the HNB and the HeNB by an Auto
Configuration Server (ACS) (e.g. an ACS according to technical report TR-069 ofthe
Broadband Forum) to be stored in the shared transfer memory associated with the operation
20 administration maintenance (OAM) module. As described above, the information elements
representing the initial configuration can therefore be retrieved by the HNB and/or the I-IeNB or
provided to the HNB andlor the NeNB by the OAM module using an appropriate message.
Advantageously, in each of the examples described above, the home base station parts are
configured for the transfer of iilformation elements associated with or comprising any ofthe
25 following:
a configuration of at least one of the first and second base station modules,
a Physical Cell Identifier (PCI),
a Primary Scrambling Code (PSC),
a carrier frequency,
30 a static parameter information element, for instance a static cell parameter
information element,
a dynamic parameter information element, for instance a dynamic cell parameter
information element,
System Infornlation such as UMTS system information for the I-INB part, and
a neighbour cell list.
The static parameter information element comprises at least one of:
a maximum number of UE that a base station module is configured to serve
(MaxUEsServed),
5 a maximum number of closed subscriber group (CSG) members that a base
station module is configured to serve (MaxCSGMembers),
a maximum number of non CSG members that a base station module is
configured to serve (MaxNonCSGMembers).
The dynamic parameter information element comprises at least one of:
a current number of CSG UE which are being served by a base station module,
a current number of non CSG UE which are being served by a base station
module, and
a load/congestion status of a base station module.
The transfer mechanisms described are particularly advantageous in a number of
15 situations.
Beneficially, by providing for the PCIIPSC and/or carrier frequency to be obtained from
a coexisting home base station function using an internal or external transfer mechanism, if one
home base station part (e.g the HeNB) reselectslchanges its PCIIPSC and/or carrier frequency
dynamically, the other part (e.g. the IINB) can obtain the information without having to wait for
20 the NMM to be performed (resulting in the HNB having the wrong data stored in its neighbour
cell information related to HeNB). Similarly, by providing for the configuration information
provided by the ACS for a coexisting home base station part to be obtained from a coexisting
home base station function using an internal or external transfer mechanism, the configuration
information can be obtained proinptly without having to wait for the ACS to provide it. This is
25 particularly advantageous, for example, because handover to the HeNB may fail or may not
occur when it should if the wrong parameters (e.g. PCIICarrier Frequency) are stored at the
HNB.
Moreover, by providing for neighbour cell information to be obtained from a coexisting
home base station function using an internal or external transfer mechanism, if the NMM is
30 operated at a different time by the I4NB than the IleNB, or if the I-leNB identifies a greater
number of neighbours than IINB by virtue of an automatic neighbour (ANR) procedure, the
neighbour cell information can advantageously be synchronised between the IINB and HeNB to
avoid the HNB and HeNB having different neighbour cell information to one another.
Beneficially, by providing for UMTS System Information for HNB to be obtained from a
coexisting home base statio~lf unction using an internal or external (SON based) transfer
mechanism, if one home base station part (e.g. the HeNB) needs to perform a circuit switched
fallback (CSFB) procedure (e.g. as defined in 3GPP TS 36.300), via redirection to the HNB, the
HeNB does not need to retrieve this information using the current signaling intensive Radio
5 Access Network (RAN) Information Management (RIM) procedure via the core network 8.
Accordingly, traffic towards the core network 8 can be reduced.
Beneficially, by providing for the static parameters such as MaxUEsServed, and dynamic
parameters such as current CSG UEs, and congestion/load status to be obtained from a
coexisting home base station function, using an internal or external (SON based) transfer
10 mechanism, potential handover failure can be detected early thereby allowing unnecessary
handover signaling associated with a failed handover attempt to be avoided.
For example, even i f the NMM is not perfonned by a particular home base station part to
monitor immediately the reselection and change of at least one of the PCI, PSC and carrier
frequency by the other base station module of the dual FAP or even if the TR-069 ACS and the
15 NMM module do not send immediately updated information elements to at least one of the base
station module as regards to the NMM results, the information element corresponding to the
updated PCI, PSC, the carrier frequency and the Neighbour Cell List may be transmitted to the
base station module. Both the base stations therefore may have updated information elements as
regards to at least one of the PCI, PSC and carrier frequency of the other base station module of
20 the dual FAP and the PCI, PSC and carrier frequency of neighbour base station modules. In the
example of a handover, the source base station module may have access to the information
element about the static parameter information element and the dynamic parameter information
element of the target base station module, to make a decision about initiating a handover. This
results in a more efficient decision for initiating a handover, a more successful handover
25 procedure, and a reduction in unnecessary signalling over the communications network.
Modifications and Alternatives
Detailed embodiments have been described above. As those skilled in the art will
appreciate, a number of modifications and alternatives can be made to the above embodiments
whilst still benefiting from the inventions embodied therein.
30 In the above embodiments, a mobile telephone based teleco~~~~~~uniscyastteio~ntw~ ass
described. As those skilled in the art will appreciate, the signalling techniques described in the
present application can be employed in other communications systems. Other communications
nodes or devices may include user devices such as, for example, personal digital assistants,
laptop conlputers, web browsers, etc.
In the e~nbodimentsd escribed above, the mobile telephone and the HNB or I-IeNB each
include transceiver circuitry. Typically this circuitry will be formed by dedicated hardware
circuits. However, in sonle embodiments, part of the transceiver circuitry may be i~nplemented
as software run by the corresponding controller.
5 It should of course be appreciated that, although not explicitly shown in Figures 2a, 2b,
2c, 3 and 4a, 4b, and 4c the base stations 11 and UEs 3 will have all of the functionality
necessary to enable them to operate as base stations and UEs, respectively, in the particular
system in which they are designed to function. It should also be appreciated that Figures 2a, 2b,
2c, 3 and 4a, 4b, and 4c are functional block diagrams and that in practice the individual blocks
10 shown in Figures 2a, 2b, 2c, 3 and 4a, 4b, and 4c may exist as discrete elements or their
functionality may be distributed or not individually discernable. As an example, the modules 3 1
to 41 may or may not be separate software modules.
Although the above description of Figures 2a, 2b, 2c, 3 and 4a, 4b, and 4c indicates that
the described functionality is provided by software, it should be appreciated that the functionality
15 of a UE or base station may be provided, where appropriate, by hardware, software, firmware or
any co~nbinationth ereof. As an example, the functionality performed by part or all of the abovedescribed
software may be performed using one or more dedicated hardware circuits. A
software implementation may however be preferred to facilitate the updating of the functionality
of a base station 11 or UE 3.
20 Where software modules are provided, they may be provided, as appropriate, in compiled
or un-compiled form and may be supplied to the base station or to the UE, as the case may be, as
a signal over a computer or telecom~nunicationsn etwork, or on a computer storage medium such
as for instance a CD ROM.
"Various other modifications .will be apparent to those skilled in the art and will not be
25 described in further detail here.
For instance, the base stations of the multimode femto access point might implement any
of the example alone or any combination of the examples, depending on the circumstances and
the conditions.
Although the invention has been described with particular refcrence to embodiments
30 comprising the transfcr of at least onc infor~nationc len~cnbt ctween the IINBIIIeNB parts ofa
dual FAP, the invention may also be beneficially employed in embodiments comprising the
transfer of an information element between two macro cells or between a femto cell and a macro
cell.
The invention therefore also relates to the transfer of information element bctween an
evolved UTRAN (E-UTRAN) base station and a Universal Terrestrial Radio Access Network
(UTRAN) base station or between a home base station (HeNB or I-INB) and a macro cell (EUTRAN
or U'TRAN).
Beneficially and as a non limiting example, by providing for instance the PCIIPSC and/or
5 carrier frequency by a mechanism according to aspects of the invention, if one base station (e.g.
a HeNB or an E-UTRAN) reselects/changes its PCIIPSC and/or carrier frequency dynamically,
the other base station (e.g. a HNB or a UTRAN respectively) can obtain the information
promptly. The transfer may be an external mechanism, for example, via comn~unicationw ith
another communications node such as a Serving GPRS Support Node (SGSN), elsewhere in the
10 communication network for instance in the core network. This is particularly advantageous, for
example, because handover to the HeNB may fail or may not occur when it should if the wrong
parameters (e.g. PCIICarrier Frequency) are stored at the HNB.
This application is based upon and claims the benefit of priority from United Kingdom
patent application No. 1120963.2, filed on December 6,201 1, the disclosure of which is
15 incorporated herein in its entirety by reference.
20
CLAIMS
1. A colnmunications apparatus comprising:
a first base station module for providing wireless connectivity to a con~munications
5 network to one or more mobile communications devices within range of the first base station
module;
a second base station module for providing wireless connectivity to a communications
network to one or more mobile communications devices within range of the second base station
modtlle; and
10 means for transferring, internally to said communication apparatus, at least one
information element from one of the first and second base station modules to the other one of the
first and second base station modules.
2. A colnmunications apparatus according to claim 1, wherein the transferring means
15 comprise an internal interface for coupling the first base station module and the second base
station module.
3. A communications apparatus according to any of claims 1 or 2, wherein at least one of
the first and second base station modules is configured to provide at least one information
20 element to the transferring means, wherein the transferring means comprise a memory to store
the provided at least one information element, and wherein the other of the first and second base
station modules is configured to retrieve the provided at least one information element from the
memory of the transferring means.
25 4. A communications apparatus according to any one of claims 1 to 3, wherein at least
one of the first and second base station modules is configured to provide at least one information
element to the transferring means, wherein the transferring means comprise a memory to store
the provided at least one information element, and wherein the transferring means are configured
to provide the information element provided by the at least one of the first and second base
30 station lnodules to the other of the first and second base slation modules.
5. A communications apparatus according to any one of claims 1 to 4, wherein the
transferring means comprise an operation administration maintenance module comprising a
memory.
6. A communications apparatus according to any one of claims 2 or any claim dependent
therefrom, wherein at least one of the first and second base station modules is configured to
provide at least one information element to the other one of the first and second base station via
5 the interface.
7. A communications apparatus according to claim 2 or any claim dependent therefrom,
wherein at least one of the first and second base station modules is configured to request at least
one information element from the other one of the first and second base station via the interface.
10
8. A communications apparatus according to any one of claims 2 or any claim dependent
therefrom, wherein the interface comprises an interface module which comprises at least one
controller module for at least one of the first and second base station modules.
9. A communications apparatus according to one of claims 1 to 8, wherein at least one of
the first and second base station modules is configured to provide at least one information
element to the other one of the first and second base station via the interface, in response to a
request from a controller module.
10. A communications apparatus comprising:
a first base station module for providing wireless connectivity to a communications
network to one or more mobile communications devices within range of the first base station
module;
a second base station module for providing wireless connectivity to a communications
25 network to one or more mobile communications devices within range of the second base station
module; and
means for transferring at least one information element from one of the first and second
base station n~odulesto the other one of the first and second base station modules, wherein said
transferring means comprises:
means, provided in said first base station module, for generating and sending a
request identifying at least one required information element to a communication node of
said communication network;
means, provided in said second base station module, for receiving said request
from said colnmunication node and for sending a response to said request comprising
said requested at least one required information element; and
means, provided in said first base station module, for receiving said response.
I I. A communications apparatus according to claim 10, wherein the communication node
5 comprises a node of a core network.
12. A communications apparatus according to any one of claims 10 or 1 1, wherein the
request and the response comprise messages in accordance with a Self Organizing Network
(SON) Transfer protocol.
10
13. A communications apparatus according to claim 12, wherein the messages in
accordance with thc Self Organizing Network (SON) Transfer protocol comprise a SON
Information Transfer message, and wherein the at least one information element is added to the
SON Information Transfer message, as any one of:
15 a SON Transfer Application Identity information element, or
a SON Transfer Request Container information element, or
a SON Transfer Response Container information element.
14. A communications apparatus according to any one of claims 1 to 13, wherein the at
20 least one information element comprises at least one of:
a configuration of at least one of the first and second base station modules,
a Physical Cell Identifier (PCI),
a Primary Scrambling Code (PSC),
a carrier frequency,
a static parameter information element,
a dynamic parameter information element,
System Information, such as UMTS system information, and
a neighbour cell list.
30 15. A conlmunications apparatus according to claim 14, wherein the static parameter
information element comprises at least one of:
a n~aximunn~um ber of UE that a base station module is configured to serve
(MaxUEsServed),
a maximum number of closed subscriber group (CSG) rtlembers that a base station
23
module is configured to serve (MaxCSGMembers),
a maximum number of non CSG ~ne~nbetrhsa t a base station module is configured to
serve (MaxNonCSGMembers),
and wherein the dynamic parameter information element comprises at least one of:
5 a current number of CSG UE which are being served by a base station module,
a currcnt number of non CSG UE which are being served by a base station module, and
a load or congestion status of a base station module.
16. A communications apparatus according to any one of claims 1 to 15, wherein the first
10 base station module and thc second base station module are mounted within a common housing.
17. A communications apparatus according to any one of claims 1 to 16, wherein the
communications apparatus comprises a dual mode femto access point.
18. A communications apparatus according to any one of claims 1 to 17, wherein at least
one of the first and second base station modules comprises a HNB and the other of the first and
second base station modules comprises a HeNB.
19. A communications apparatus according to any one of claims 1 to 18, wherein said
20 transferring means is configured for transferring, internally to said communication apparatus said
at least one information element or for transferring said at least one information element via a
communication node of said communication network external to said communication apparatus
in dependence on the at least one information element being transferred.
25 20. A system for use in a telecommunications network, comprising one or more mobile
communications devices and a communications apparatus according to any one of claims 1 to
19.
21. A mobile communications device for use with a communications apparatus
30 comprising: a first base station module for providing wireless connectivity to a comtnunicatiotis
network to onc or more mobile comn~unicationsd evices within range of thc first basc station
module; a second base station module for providing wireless connectivity to a communications
network to one or more mobile communications devices within range of the second base station
module; an interface for coupling the first base station module and the second base station
module; wl~ereina t least one of the first and second base station inodules is configured to
. exchange, internally to said comtnunication apparatus, at least one information element with the
other one of the first and second base station modules via said interface, and
wherein the mobile con~municationsd evice is arranged to communicate a
5 communications network via one ofthe first and second base station modules ofthe
communications apparatus.
22. A method, performed in a telecommunications network, for facilitating exchange of
at least one information element between two base station modules of a communications
10 apparatus, the method comprising exchanging at least one information element, over an internal
interface coupling the two base station ntodules.
23. A method, performed in a telecommunications network, for facilitating exchange of
at least one information element between two base station modules of a communications
15 apparatus, the method comprising exchanging at least one information element via transferring
means comprising an operation administration maintenance module comprising a memory.
24. A method, performed in a telecommunications network, for facilitating exchange of
at least one information element between two base station modules of a communications
20 apparatus, the method comprising exchanging at least one information element via transferring
means for transferring said at least one information element via a communication node of said
comtnunication network external to said coinmunication apparatus.
25. A method according to claim 24, wherein the transferring means:
25 generate and send a request identifying at least one required information element froill a
first base station module to a communication node of said cominunication network,
receive said request from said comm~inicationn ode and send from a second base station
module a response to said request comprising said requested at least one required information
element; and
receive said response in thc first base station module.
26. A method according to claim 25, wherein the request and the response comprise a
SON Information Transfer message in accordance with a Self Organizing Network (SON)
Transfer protocol, and wherein the at least one required information element is added to tlte SON
Information Transfer message, as any one of:
a SON Transfer Application Identity information element, or
a SON Transfer Request Container information element, or
a SON Transfer Response Container information element.
5
27. A communications apparatus comprising:
a first base station module for providing wireless connectivity to a communications
network to one or more mobile communications devices within range of the first base station
module;
10 means for transferring at least one information element from a second base station
module, for providing wireless connectivity to a communications network to one or more mobile
communications devices within range of the second base station module, to the first base station
module, wherein said transferring means comprises:
means, provided in said first base station module, for generating and sending a
15 request identifying at least one required information element to a communication node of
said communication network; and
means, provided in said first base station module, for receiving a response to said
request from the second base station module, the response comprising said requested at
least one required information element.
20
28. A method, performed in a telecommunications network, for facilitating exchange of
at least one information element between two base station modules of the network, the method
comprising exchanging at least one information element via transferring means for transferring
said at least one info'mation element via a communication node of said communication network,
25 wherein the transfening means:
generate and send a request identiijing at least one required information element from a
first base station module to a communication node of said communication network,
receive said request from said communication node and send from a second base station
module a response to said request comprising said requested at least one required information
30 element; and
receive said response in the first base station module.
29. A computer program, computer program product or computer readable medium
comprising instructions for carrying out a method according to any of claims 22 to 26 or 28.