WO2015113640A1

WO2015113640A1 - Method, apparatus and computer program for allowing communication between base stations

Info

Publication number: WO2015113640A1
Application number: PCT/EP2014/052027
Authority: WO
Inventors: Jani Matti Johannes Moilanen; Esa Markus METSÄLÄ; Jose Manuel TAPIA-PEREZ; Jouko Juhani Kapanen
Original assignee: Nokia Solutions And Networks Oy
Priority date: 2014-02-03
Filing date: 2014-02-03
Publication date: 2015-08-06
Also published as: EP3103300A1

Abstract

A method comprising processing, in an apparatus of a base station, first data for a second base station separately from second data for said second base station.

Description

Title

METHOD, APPARATUS AND COMPUTER PROGRAM FOR ALLOWING COMMUNICATION BETWEEN BASE STATIONS

This disclosure relates to methods and apparatus and in particular but not exclusively to method and apparatus for allowing communication between base stations. A communication system can be seen as a facility that enables communication sessions between two or more nodes such as fixed or mobile devices, machine-type terminals, access nodes such as base stations, servers and so on. A communication system and compatible communicating entities typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. For example, the standards, specifications and related protocols can define the manner how devices shall communicate, how various aspects of communications shall be implemented and how devices for use in the system shall be configured. A user can access the communication system by means of an appropriate communication device. A communication device of a user is often referred to as user equipment (UE) or terminal. A communication device is provided with an appropriate signal receiving and transmitting arrangement for enabling communications with other parties. Typically a device such as a user equipment is used for enabling receiving and transmission of communica- tions such as speech and content data.

Communications can be carried on wireless carriers. Examples of wireless systems include public land mobile networks (PLMN) such as cellular networks, satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). In wireless systems a communication device provides a transceiver station that can communicate with another communication device such as e.g. a base station of an access network and/or another user equipment. The two directions of communications between a base station and communication devices of users have been conventionally referred to as downlink and uplink. Downlink (DL) can be understood as the direction from the base station to the communication device and uplink (UL) the direction from the communication device to the base station. Inter-cell interference mitigation may be a consideration for improving the performance of a communication system. According to an aspect there is provided a method comprising processing, in an apparatus of a base station, first data for a second base station separately from second data for said second base station.

The first data may relate to information that is more time-critical than the second data related information.

The first data may relate to control signalling information.

The first data may relate to inter-cell interference control information.

The second data may relate to at least one of control or user plane signalling.

The method may comprise causing said first data to be sent on a first path and said second data to be sent on a second path.

The method may comprise processing the first data before the second data.

The method may comprise causing the first data to be sent before the second data. The method may comprise allocating resources solely for the first data.

The method may comprise providing security services for the second data.

The method may comprise providing security services for the first data using a first set of security parameters and for the second data using a second set of security parameters.

The security service may be at least one of an encryption service, integrity protection service and origin authentication service. The method may comprise causing the first data to be mapped to a first endpoint and the second data to be mapped to a second endpoint. The first endpoint may be the first common node between base stations.

The endpoint may be at least one of an IP endpoint and an IP security tunnel endpoint. The method may comprise causing the first endpoint information to be sent with transfer related information.

The transfer related information may be self-optimising network configuration transfer information.

The base stations may be eNBs.

According to another aspect there is provided a data structure comprising first data to be sent from a first base station to a second base station, second data to be sent from a first base station to a second base station, wherein the first data is processed separately from the second data.

According to another aspect, there is provided an apparatus, said apparatus comprising at least one processor and at least one memory including computer code for one or more pro- grams, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to: process in an apparatus of a base station, first data for a second base station separately from second data for said second base station. The first data may relate to information that is more time-critical than the second data related information.

The first data may relate to control signalling information.

The first data may relate to inter-cell interference control information. The second data may relate to at least one of control or user plane signalling.

The at least one processor and at least one memory may be configured to cause said first data to be sent on a first path and said second data to be sent on a second path. The at least one processor and at least one memory may be configured to process the first data before the second data. The at least one processor and at least one memory may be configured to cause the first data to be sent before the second data. The at least one processor and at least one memory may be configured to allocate resources solely for the first data.

The at least one processor and at least one memory may be configured to provide security services for the second data.

The at least one processor and at least one memory may be configured to provide security services for the first data using a first set of security parameters and for the second data using a second set of security parameters. The security service may be at least one of an encryption service, integrity protection service and origin authentication service.

The at least one processor and at least one memory may be configured to cause the first data to be mapped to a first endpoint and the second data to be mapped to a second end- point.

The first endpoint may be the first common node between base stations.

The endpoint may be at least one of an IP endpoint and an IP security tunnel endpoint.

The at least one processor and at least one memory may be configured to cause the first endpoint information to be sent with transfer related information.

The transfer related information may be self-optimising network configuration transfer infor- mation.

The base stations may be eNBs.

According to another aspect there is provided an apparatus, said apparatus comprising means for processing, in an apparatus of a base station, first data for a second base station separately from second data for said second base station. The first data may relate to information that is more time-critical than the second data related information.

The first data may relate to control signalling information.

The first data may relate to inter-cell interference control information.

The second data may relate to at least one of control or user plane signalling.

The apparatus may comprise means for causing said first data to be sent on a first path and said second data to be sent on a second path.

The apparatus may comprise means for processing the first data before the second data.

The apparatus may comprise means for causing the first data to be sent before the second data.

The apparatus may comprise means for allocating resources solely for the first data.

The apparatus may comprise means for providing security services for the second data.

The apparatus may comprise means for providing security services for the first data using a first set of security parameters and for the second data using a second set of security parameters.

The security service may be at least one of an encryption service, integrity protection service and origin authentication service.

The apparatus may comprise means for causing the first data to be mapped to a first end- point and the second data to be mapped to a second endpoint.

The first endpoint may be the first common node between base stations.

The endpoint may be at least one of an IP endpoint and an IP security tunnel endpoint. The apparatus may comprise means for causing the first endpoint information to be sent with transfer related information.

The base stations may be eNBs.

According to another aspect, there is provided a computer program comprising program code means adapted to perform the method(s) may also be provided. The computer program may be stored and/or otherwise embodied by means of a carrier medium.

Reference is now made by way of example only to the accompanying drawings in which: Figure 1 shows a schematic diagram of a communication system comprising a base station and a plurality of communication devices;

Figure 2 shows a schematic diagram of a mobile communication device according to some embodiments;

Figure 3 shows a schematic diagram of a basic Evolved Universal Terrestrial Radio Access Network (E-UTRAN) architecture;

Figure 4 shows a schematic diagram of a logical interface between two base stations;

Figure 5 shows a method of operation of a control apparatus of a base station;

Figure 6 shows a schematic diagram of an alternative logical interface between two base stations;

Figure 7 shows a schematic diagram of a control apparatus according to some embodiments;

In the following certain exemplifying embodiments are explained with reference to a wireless or mobile communication system serving mobile communication devices. Before explaining in detail the exemplifying embodiments, certain general principles of a wireless communica- tion system and mobile communication devices are briefly explained with reference to Figures 1 to 2 to assist in understanding the technology underlying the described examples.

In a wireless communication system 100 mobile communication devices or user equipment (UE) 102, 103, 105 are provided wireless access via at least one base station or similar wireless transmitting and/or receiving node or point. Base stations are typically controlled by at least one appropriate controller apparatus, so as to enable operation thereof and management of mobile communication devices in communication with the base stations. Base stations may comprise base band pools. The controller apparatus may be part of the base sta- tion and/or provided by a separate entity such as a Radio Network Controller. In Figure 1 control apparatus 108 and 109 are shown to control the respective macro base stations 106 and 107. The control apparatus of a base station can be interconnected with other control entities. The control apparatus is typically provided with memory capacity and at least one data processor. The control apparatus and functions may be distributed between a plurality of control units. In some systems, the control apparatus may additionally or alternatively be provided in a radio network controller.

In Figure 1 base stations 106 and 107 are shown as connected to a wider communications network 1 13 via gateway 1 12. A further gateway function may be provided to connect to an- other network.

The smaller base stations 1 16, 1 18 and 120 may also be connected to the network 1 13, for example by a separate gateway function and/or via the controllers of the macro stations. In the example, stations 1 16 and 1 18 are connected via a gateway 1 1 1 whilst station 120 con- nects via the controller apparatus 108. In some embodiments, the smaller stations may not be provided.

A possible mobile communication device will now be described in more detail with reference to Figure 2 showing a schematic, partially sectioned view of a communication device 200. Such a communication device is often referred to as user equipment (UE) or terminal. An appropriate mobile communication device may be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a mobile station (MS) or mobile device such as a mobile phone or what is known as a 'smart phone', a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), personal data assistant (PDA) or a tablet provided with wireless communication capabilities, or any combinations of these or the like. A mobile communication device may provide, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on. Users may thus be offered and provided numerous services via their communication devices. Non-limiting examples of these services include two-way or multi-way calls, data communication or multimedia services or simply an access to a data communications network system, such as the Internet. Users may also be provided broadcast or multicast data. Non-limiting examples of the content include downloads, television and radio programs, videos, advertisements, various alerts and other information. The mobile device 200 may receive signals over an air or radio interface 207 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Figure 2 transceiver apparatus is designated schematically by block 206. The transceiver apparatus 206 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

A mobile device is typically provided with at least one data processing entity 201 , at least one memory 202 and other possible components 203 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and com- munications with access systems and other communication devices. The data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 204. The user may control the operation of the mobile device by means of a suitable user interface such as key pad 205, voice commands, touch sensitive screen or pad, combinations thereof or the like. A display 208, a speaker and a microphone can be also provided. Furthermore, a mobile communication device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto.

The communication devices 102, 103, 105 may access the communication system based on various access techniques, such as code division multiple access (CDMA), or wideband CDMA (WCDMA). Other non-limiting examples comprise time division multiple access (TDMA), frequency division multiple access (FDMA) and various schemes thereof such as the interleaved frequency division multiple access (IFDMA), single carrier frequency division multiple access (SC-FDMA) and orthogonal frequency division multiple access (OFDMA), space division multiple access (SDMA) and so on. An example of wireless communication systems are architectures standardized by the 3rd Generation Partnership Project (3GPP). A latest 3GPP based development is often referred to as the long term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. The various development stages of the 3GPP specifica- tions are referred to as releases. More recent developments of the LTE are often referred to as LTE Advanced (LTE-A). The LTE employs a mobile architecture known as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN). Base stations of such systems are known as evolved or enhanced Node Bs (eNBs) and provide E-UTRAN features such as user plane Radio Link Control/Medium Access Control/Physical layer protocol (RLC/MAC/PHY) and control plane Radio Resource Control (RRC) protocol terminations towards the communication devices. Other examples of radio access system include those provided by base stations of systems that are based on technologies such as wireless local area network (WLAN) and/or WiMax (Worldwide Interoperability for Microwave Access). LTE systems may however be considered to have a so-called "flat" architecture, without the provision of RNCs; rather the (e)NB is in communication with a system architecture evolution gateway (SAE-GW) and a mobility management entity (MME), which entities may also be pooled meaning that a plurality of these nodes may serve a plurality (set) of (e)NBs. Each UE is served by only one MME and/or S-GW at a time and the (e)NB keeps track of current association. SAE-GW is a "high-level" user plane core network element in LTE, which may consist of the S-GW and the P-GW (serving gateway and packet data network gateway, respectively). The functionalities of the S-GW and P-GW may be separated and they are not required to be co-located. As shown in figure 3, X2 is a logical interface in E-UTRAN architecture, designed to carry messages between the eNBs. It may carry time critical information, such as channel quality measurements and/or radio resource control messages, for the purpose of interference coordination between cells. S1 is the logical interface between the E-UTRAN and the evolved packet core. S1 -U connects the eNB to the S-GW, S1 -MME connects the eNB to the MME. The packets that are sent over S1 and X2 may be routed partly via same path.

As shown in figure 4, the X2 interface may be built as Stream Control Transmission Protocol (SCTP internet Protocol (IP) connectivity between two eNBs, via a central security gateway (SEG), such that an IPsec tunnel exists from eNB1 to a central SEG and then another IPsec tunnel from the SEG to the eNB2 forming a topology which may be known as "X2-star". 3GPP specifications also enable X2-mesh technology (i.e. direct IPsec tunnel between two eNBs) which can be considered as an alternative to the X2-star topology.

Various methods of interference mitigation have been introduced in 3GPP specifications for increasing cell throughput and network capacity in LTE/LTE-A, such as elCIC (enhanced Inter-Cell Interference Coordination) in Rel. 10 and CoMP (Coordinated Multi-Point) in Rel.1 1. In addition, further interference mitigation options are currently being developed for Rel. 12, including felCIC (further enhanced ICIC) and eCoMP (enhanced CoMP). elCIC attempts to mitigate interference in Heterogeneous Networks (HetNets) by controlling in the time domain the transmissions of overlapping macro and small (low power) cells. A macro eNB provides so called "ABS (almost blank subframes) muting pattern" to the low power nodes that indicates the time slots during which the macro eNB transmits only certain reference signals that are mandatory for the legacy devices, but is otherwise muted. During these almost blank sub-frames, the low power nodes can schedule cell edge UEs that would otherwise suffer from high interference caused by the high power macro eNB. In order to achieve efficient use of radio resources, the macro eNB may dynamically adjust the ABS muting pattern to reflect the varying load and radio conditions. Similarly, elCIC may be applied also to mitigate interference between (high power) macro cells or between (low power) small cells.

With eCoMP, similar coordinated muting mechanisms are proposed, but the muting might be decided on a sub-frame level (for example, a new muting decision may be made for every 1 ms TTI, Transmission Time Interval) and per sub-band (for example, during same TTI only part of the overall band may be muted).

In the context of eCoMP different architecture options are available. One option is to use distributed architecture and extend the existing X2 interface. Alternatively, a centralized architecture with a centralized controller entity for LTE RAN, and an alternative interface between eNB and the centralized controller entity may be used. The term X2 is used herein to refer to any logical interface between base stations, and Xn to any logical interface between base stations and centralised coordination entities that can be used to transmit information between the cells. In addition to the above mentioned time domain coordination methods, various other variants have been standardized/proposed where the coordination happens in frequency, power, and/or space domains. The term ICIC is used herein to mean any possible approach that coordinates interference between cells.

Common to the interference coordination methods is that they may benefit from fast control information exchange, i.e. from low latency in the interface that carries the time-critical in- formation, such as the X2 interface. The lower the latency, the better the performance of the interference mitigation.

Some of the coordination methods can cope with few tens of milliseconds one-way latency for the control signalling, while other methods require much faster (a few milliseconds, or even sub-millisecond) latencies. The latency requirements depend also on how fast the changes in the load and radio conditions are. Therefore, latency requirements may change and become more onerous, e.g. if traffic is more bursty and/or coordination is applied to UEs with higher mobility. X2 delay can be minimised through network design, having faster links and smaller forwarding delays. However, complete transport network redesign to improve latency may be costly and networks may not be optimised from a latency point of view.

Figure 5 shows a flow chart of a method for optimising latency for control signalling informa- tion in a logical interface. Although this method is described with reference to an X2 interface, it is equally applicable to an Xn interface as defined above. The eNB identifies the time critical related control information and processes it separately from other, less time critical X2 AP (application protocol) information. The time critical information may be time critical ICIC related information. Examples of such other X2 AP information include, but are not lim- ited to, signalling related handover preparation, SN status, UE context release, or handover cancel procedures.

ICIC related time-critical measurement/other information may be, firstly, separated from all other X2AP messages by a control apparatus of the eNB. This allows the eNB to internally process ICIC messages with a higher priority with respect to other received/to be generated X2 AP messages. Secondly, ICIC messages may be processed with higher priority to any other, less time critical information, such as user plane information sent via X2 (e.g. user data that is forwarded during handover procedure) or information sent via other interfaces (e.g. user and control plane information sent via S1 interface). Having differentiated processing in the eNB for ICIC signalling may mean that ICIC messages are processed faster compared to other X2 or S1 messages. Alternatively, or in addition, ICIC messages may be potentially constructed on a separate HW (hardware) assisted path compared to other X2 or S1 messages, and/or resources may be specifically allocated for ICIC messages.

Differentiated treatment in the transport network could mean e. g. use of different IP Differentiated Services Code Point (DSCP) and/or Ethernet priority marking such as 802.1 q priority bits. The different priority marking may be either in the unencrypted IP packet, the Ethernet frame, and/or on the outer IP packet of the IPsec protected tunnel. The different priority marking may also, or as an alternative, be on the underlying Ethernet frame carrying the outer encrypted IP packet.

Differentiated processing in eNB and in transport network may reduce risks and/or interdependences of time-critical ICIC information transfer from the non-time-critical (control or user plane) operation.

The operator may configure IPsec protection options separately for ICIC signalling, or may bypass IPsec protection for ICIC while keeping IPsec protection for other X2AP. With IPsec it is possible to select the options for the ICIC signalling, for example: protection with ESP (Encapsulating Security Payload) only including authentication (no encryption). Since a lower amount of traffic is needed for ICIC compared to overall X2 signalling, latency in the IPsec operations may be reduced. There may also be a separate optimized IPsec processing engine or component dedicated for the ICIC signalling only.

In another alternative, IPsec protection for ICIC signalling may be bypassed. Although tampering with the ICIC info may cause degradation/outage of radio performance, vulnerable information such as subscriber identities, is not revealed. A further alternative is to use all confidentiality, integrity and origin authenticity services with IPsec, or any combination thereof. When the ICIC messages are separated from other X2 information, cryptographic protection (IPsec) may not be used at all for ICIC signalling or a separate IPsec SA (Security Association) may be used for ICIC signalling alone (in which case the other X2 information is assumed to be protected by another IPsec SA).

In all of these cases, it is possible to have differentiated treatment for the ICIC signalling in the eNB and/or in the transport network (different DSCP marking for the ICIC messages, (e. g. strict priority), and/or a different direct path for ICIC signalling between neighbour eNBs). In the case where there is no IPsec protection for ICIC signalling, latency is reduced, compared to the alternative of full X2 IPsec mesh, because IPsec processing operations (such as encryption/decryption) are bypassed, but security is not compromised, neither for the other X2 signalling (which may still use IPsec protection with a centralized SEG) nor for the ICIC signalling (since IPSec protection is not mandatory). Network deployment complexity may also be reduced, because there is no need for IPsec X2 mesh. Protecting full X2 with IPsec means full mesh connectivity between neighbour nodes. With IPsec X2 mesh, for e.g. 6 eNB neighbour cluster, a total of (6^*5)/2 or 15 IPsec SAs would be needed per direction. In addition, separate IPsec SA for the S1 is needed, further increasing the complexity. There may also be a limit in terms of SAs that eNB can support.

Overall, separated faster processing for ICIC related information within the eNB compared to other X2/S1 processing may be achieved.

Once the ICIC information is processed and completed it may be mapped to the protocol stack defined by 3GPP which may be SCTP over IP, and optionally IPsec. ICIC information may also be mapped to other transport layer (L4) protocol options using e. g. UDP or TCP instead of SCTP, and then further carried over IP(either IPv4 or IPv6 could be used).

As shown in figure 6, in the network topology, the ICIC traffic may go from eNB1 to the dis- tribution edge (or the first common network node in the topology) and then back to eNB2, while other X2 traffic may be directed to the central security gateway (SEG). Because of this direct connectivity, latency can be reduced.

The discovery of the IPsec tunnel endpoint address and the endpoint address of the ICIC of the peer eNB may be separate from the discovery of the "general" X2AP endpoint and IPsec tunnel endpoint addresses. A separate endpoint allows an operator to route traffic separately from other X2AP. The endpoint may be a separate IP endpoint or a separate IPsec tunnel endpoint.

The operator may configure a separate path and separate QoS to ICIC information in the transport network, e.g. using a separate SCTP association(s) for the ICIC messages with a different DSCP for the IP packets carrying ICIC information. SCTP association consists of local and remote endpoints, where endpoints consist of local SCTP port number and list of local IP addresses. Thus separate IP address(es) from that of "general" X2AP may be defined for the SCTP association used for ICIC.

As mentioned, protocols other than SCTP (e.g. UDP or TCP) may be used to carry ICIC information, in which case separate path and separate QoS for this traffic may be required, with details depending on the protocols used. In this case similarly a separate endpoint from that of the general X2AP may be defined (endpoint e.g. as a local UDP or TCP port number and local IP address).

Depending on the latency requirements, it may also be that the ICIC information would be directed to use a transport service that avoids the currently defined protocol stack, to avoid delays of protocol processing. This could be achieved e. g. by a CPRI (Common Public Ra- dio Interface) or a OBSAI (Open Base Station Architecture Initiative) type of interface, carried over a physical layer such as a fibre interface, an electrical interface, or wireless interface directly between the peer elements.

The ICIC connectivity to the peer eNB may be automatically discovered using e.g. en- hancements to the procedures currently defined in 3GPP. The current definition is in TS 36.300 , e. g. in section 22.3.6 "TNL address discovery" and in TS 36.413 section 8.16.2.1 "MME Configuration Transfer" with further references there, defining SON (Self- optimizing network) configuration transfers. The eNB sends the eNB CONFIGURATION TRANSFER message to the MME to request the TNL address of the candidate eNB, and includes relevant information such as the source and target eNB ID. The MME relays the request by sending the MME CONFIGURATION TRANSFER message to the candidate eNB identified by the target eNB ID. The candidate eNB responds by sending the eNB CONFIGURATION TRANSFER message containing one or more TNL addresses to be used for SCTP connectivity with the initiating eNB, and includes other relevant information such as the source and target eNB ID. The MME relays the response by sending the MME CONFIGURATION TRANSFER message to the initiating eNB identified by the target eNB ID.

Current standard allows discovering the TNL (Transport Network Layer) address IE for X2 AP protocol carried by SCTP and (optionally) the related IPsec tunnel endpoint. To avoid manual configuration of the potential X2-ICIC endpoint that is separate from the X2AP end- point, this information can be added to the SON configuration transfer information elements. As an example, a similar method as for discovering the X2 AP endpoint in the current standard and, optionally IPsec tunnel endpoint used for X2AP, can be used for X2-ICIC as well. Thus for the X2-ICIC, an information element regarding the X2-ICIC endpoint TNL address, and optionally TNL address of the IPsec tunnel endpoint used for X2-ICIC, can be added as a method to discover the X2-ICIC endpoints. The TNL address can be of the same format as currently defined in 3GPP.

Once the discovery of the endpoint addresses for the X2-ICIC is successful, the eNB shall automatically establish IP connectivity to the peer eNB for the ICIC.

The method may be implemented in a base station such as an eNB, or in a similar centralised entity. Figure 7 shows an example of a control apparatus for a communication system, for example to be coupled to and/or for controlling a station of an access system, such as a base station. In some embodiments, base stations comprise a separate control apparatus. In other embodiments, the control apparatus can be another network element such as a radio network controller. In some embodiments, each base station may have such a control apparatus as well as a control apparatus being provided in a radio network controller. The control apparatus 109 can be arranged to provide control on communications in the service area of the system. The control apparatus 109 comprises at least one memory 301 , at least one data processing unit 302, 303 and an input/output interface 304. Via the interface the control apparatus can be coupled to a receiver and a transmitter of the base station. For example the control apparatus 109 can be configured to execute an appropriate software code to provide the control functions which allow communication between the base stations.

The required data processing apparatus and functions of a base station apparatus, a communication device, and any other appropriate apparatus may be provided by means of one or more data processors. The described functions may be provided by one or more processors or by an integrated processor. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi core processor architecture, as non-limiting examples. The data processing may be distributed across several data processing modules. A data processor may be provided by means of, for example, at least one chip. Appropriate memory capacity can also be provided in the relevant devices. The memory or memories may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof.

Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. The soft- ware may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention as defined in the appended claims. Indeed there is a further embodiment comprising a combination of one or more of any of the other embodiments previously discussed.

Claims

1. A method comprising:

processing, in an apparatus of a base station, first data for a second base station separately from second data for said second base station.

2. A method according to claim 1 , wherein the first data relates to information that is more time-critical than the second data related information.

3. A method according to claim 1 or claim 2, wherein the first data relates to control signalling information.

4. A method according to any of the preceding claimsl , wherein the first data relates to inter-cell interference control information.

5. A method according to any one of the preceding claims, wherein the second data relates to at least one of control or user plane signalling.

6. A method according to any one of the preceding claims, comprising causing said first data to be sent on a first path and said second data to be sent on a second path.

7. A method according to any one of the preceding claims, comprising processing the first data before the second data.

8. A method according to any one of the preceding claims, comprising causing the first data to be sent before the second data.

9. A method according to any one of the preceding claims, comprising allocating resources solely for the first data.

10. A method according to any one of the preceding claims, comprising providing security services for the second data.

1 1 . A method according to any one of the preceding claims, comprising providing security services for the first data using a first set of security parameters and for the second data using a second set of security parameters.

12. A method according to claim 10 or claim 1 1 , wherein the security service is at least one of an encryption service, integrity protection service and origin authentication service.

13. A method according to any one of the preceding claims, comprising causing the first data to be mapped to a first endpoint and the second data to be mapped to a second endpoint.

14. A method according to claim 13, wherein the first endpoint is the first common node between base stations.

15. A method according to claim 13 or claim 14, wherein the endpoint is at least one of an IP endpoint and an IP security tunnel endpoint.

16. A method according to claim 15, comprising causing the first endpoint information to be sent with transfer related information.

17. A method according to claim 16, wherein the transfer related information is self- optimising network configuration transfer information.

18. A method according to any one of the preceding claims, wherein the base stations are eNBs.

19. A data structure comprising:

first data to be sent from a first base station to a second base station;

second data to be sent from a first base station to a second base station, wherein the first data is processed separately from the second data.

20. An apparatus, said apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to:

process in an apparatus of a base station, first data for a second base station separately from second data for said second base station.

21 . An apparatus according to claim 20, wherein the first data relates to information that is more time-critical than the second data related information.

22. An apparatus according to claim 20 or claim 21 , wherein the first data relates to control signalling information.

23. An apparatus according to any one of claims 20 to 22, wherein the first data relates to inter-cell interference control information.

24. An apparatus according to any one of claims 20 to 23, wherein the second data relates to at least one of control or user plane signalling.

25. An apparatus according to any one of claims 20 to 24, wherein the at least one

memory and the computer code are configured to cause the first data to be mapped to a first endpoint and the second data to be mapped to a second endpoint.

26. A computer program comprising computer executable instructions which when run are configured to perform the method of any one of claims 1 to 18.