WO2013026818A1

WO2013026818A1 - Enhancement of radio access network in the processing and forwarding of user plane data among access points

Info

Publication number: WO2013026818A1
Application number: PCT/EP2012/066173
Authority: WO
Inventors: Michael Faerber; Simone Redana; Hanns Juergen Schwarzbauer; Richard Waldhauser; Wolfgang Zirwas
Original assignee: Nokia Siemens Networks Oy
Priority date: 2011-08-24
Filing date: 2012-08-20
Publication date: 2013-02-28

Abstract

There are provided measures for an enhancement of a radio access network. Such measures may exemplarily comprise providing an enhanced RAN (e.g. E-UTRAN) architecture including a central functionality with respect to a cooperation area constituted by a plurality of (neighboring) cell, wherein such central functionality may enable enhanced radio processing in terms of a joint coordinated multipoint signal processing for the plurality of (neighboring) cells constituting the cooperation area, and wherein such central functionality may represent a core network transparent proxy function between the core network and a user in each cell.

Description

ENHANCEMENT OF RADIO ACCESS NETWORK IN THE PROCESSING AND

FORWARDING OF USER PLANE DATA AMONG ACCESS POINTS

Field of the invention

The present invention relates to an enhancement of a radio access network. More specifically, the present invention relates to measures (including methods, apparatuses and computer program products) for enhancing a radio access network .

Background

In cellular communication systems, users are typically served by (radio) cells and the (radio) signals relating to the users are typically handled and processed on a (radio) cell basis, i.e. in/for the (radio) cell in which the subject users are located individually. However, technigues of enhanced (radio) signal processing are recently being developed, which contradict such typical concept of cell-wise signal handling and processing underlying conventionally known cellular communication systems. Such technigues are based on an additional processing of (radio) signals jointly in/for multiple neighboring nodes constituting a cooperation area. For example, such technigues are currently being conceived for innovative interference avoidance solutions .

The currently specified radio access networks are not suitable for (efficiently) applying such technigues of enhanced (radio) signal processing, which reguire a joint coordinated multipoint signal processing for a plurality of (radio) cells constituting a cooperation area. According to current specifications of radio access networks in accordance with 3GPP TS 36.300, the following approaches would exemplarily be conceivable in the field of an Enhanced Universal Terrestrial Radio Access Network (E-UTRAN) .

A conceivable approach could be based on the overall basic ("flat") E-UTRAN architecture, as defined in section 4 of 3GPP TS 36.300.

Figure 1 shows a schematic diagram of a multicasting scenario for a joint coordinated multipoint signal processing on the basis of a basic E-UTRAN architecture. In Figure 1, it is exemplarily assumed that a radio access network (RAN) is constituted by seven cells each being served by an eNB and a core network (CN) is constituted by a serving gateway (S-GW) for handling user plane traffic (u-plane) for the RAN and a mobility management entity (MME) for handling control plane (c-plane) traffic for the RAN.

In such "flat" E-UTRAN architecture (without hierarchy) , UE- specific u-plane traffic is typically transmitted from the S- GW towards the eNB serving the relevant UE only. Using such "flat" E-UTRAN architecture for joint coordinated multipoint signal processing would reguire the S-GW to send UE-specific u-plane traffic not only to the eNB currently serving the relevant UE, but - by way of multicasting - in parallel to all eNBs in the cooperation area for enhanced radio

processing Furthermore, the eNBs in the cooperation area for enhanced radio processing are reguired to exchange

information for enabling joint coordinated multipoint signal processing, which is exemplarily illustrated as channel state information (CSI). Therefore, besides the fact that the traffic volume would at least be doubled, which is to be transmitted from the CN to the RAN, current CN protocols do not foresee that u-plane traffic is sent to more than one destination .

Another conceivable approach could be based on the E-UTRAN architecture supporting relaying, as defined in section 4.7 of 3GPP TS 36.300.

Figure 2 shows a schematic diagram of a multicasting scenario for a joint coordinated multipoint signal processing on the basis of an E-UTRAN architecture supporting relaying. In Figure 2, it is exemplarily assumed that a radio access network (RAN) is constituted by a cell being served by a donor eNB (DeNB), in which cell there are located seven relay cells each being served by a RN, and a core network (CN) is constituted by a serving gateway (S-GW) for handling user plane traffic (u-plane) for the RAN and a mobility management entity (MME) for handling control plane (c-plane) traffic for the RAN.

Using such E-UTRAN architecture supporting relaying

(exhibiting a hierarchy) for joint coordinated multipoint signal processing would reguire the CN (i.e. the S-GW and the MME) to send UE-specific u-plane and c-plane traffic for all RNs to the DeNB which then passes on the UE-specific u-plane and c-plane traffic to the RNs in the cooperation area by way of multicasting. As in the case of Figure 1, although not illustrated here, the RNs in the cooperation area for enhanced radio processing are reguired to exchange

information for enabling joint coordinated multipoint signal processing, e.g. channel state information (CSI). In such E- UTRAN architecture supporting relaying, no measures for enabling joint coordinated multipoint signal processing in a cooperation area for enhanced radio processing are

conventionally foreseen.

Still another conceivable approach could be based on the E- UTRAN architecture supporting home access, as defined in section 4.6 of 3GPP TS 36.300.

Figure 3 shows a schematic diagram of a multicasting scenario for a joint coordinated multipoint signal processing on the basis of an E-UTRAN architecture supporting home access (i.e. HeNBs) . In Figure 3, it is exemplarily assumed that a radio access network (RAN) is constituted by a cell, in which cell there are located seven home cells each being served by a HeNB, and a home gateway (HeNB-GW) for serving such HeNBs in terms of control-plane (c-plane) traffic, and a core network (CN) is constituted by a serving gateway (S-GW) for handling user plane traffic (u-plane) for the RAN and a mobility management entity (MME) for handling control plane (c-plane) traffic for the RAN.

Using such E-UTRAN architecture supporting home access (i.e. HeNBs) (exhibiting a hierarchy) for joint coordinated multipoint signal processing would reguire the S-GW to multicast UE-specific u-plane traffic to all HeNBs in the cooperation area for enhanced radio processing, while the MME sends UE-specific c-plane traffic only to the HeNB-GW which then passes on the UE-specific c-plane traffic to the HeNBs in the cooperation area by way of multicasting. As in the case of Figure 1, although not illustrated here, the HeNBs in the cooperation area for enhanced radio processing are reguired to exchange information for enabling joint

coordinated multipoint signal processing, e.g. channel state information (CSI) In such E-UTRAN architecture supporting home access (i.e. HeNBs), no measures for enabling joint coordinated multipoint signal processing in a cooperation area for enhanced radio processing are conventionally foreseen .

In view thereof, it is evident that currently specified radio access networks are not suitable for (efficiently) applying such technigues of enhanced (radio) signal processing, which reguire a joint coordinated multipoint signal processing for a plurality of (radio) cells constituting a cooperation area.

Thus, there is a need to further enhance a radio access network accordingly.

Summary

Various exemplary embodiments of the present invention aim at addressing at least part of the above issues and/or problems and drawbacks .

By way of exemplary embodiments of the present invention, there is provided an enhancement of a radio access network. More specifically, by way of exemplary embodiments of the present invention, there are provided measures and mechanisms for enhancing a radio access network. Such enhancement according to exemplary embodiments of the present invention relate to enabling a joint coordinated multipoint signal processing for a plurality of (radio) cells constituting a cooperation area.

Thus, improvement is achieved by methods, apparatuses and computer program products capable of enhancing a radio access network in terms of a joint coordinated multipoint signal processing for a plurality of (radio) cells constituting a cooperation area.

Brief description of drawings

For a more complete understanding of exemplary embodiments of the present invention, reference is now made to the following description taken in connection with the accompanying drawings in which:

Figure 1 shows a schematic diagram of a multicasting scenario for a joint coordinated multipoint signal processing on the basis of a basic E-UTRAN architecture,

Figure 2 shows a schematic diagram of a multicasting scenario for a joint coordinated multipoint signal processing on the basis of an E-UTRAN architecture supporting relaying,

Figure 3 shows a schematic diagram of a multicasting scenario for a joint coordinated multipoint signal processing on the basis of an E-UTRAN architecture supporting home access,

Figure 4 shows a schematic diagram of a multicasting scenario for a joint coordinated multipoint signal processing on the basis of an enhanced radio access network architecture according to exemplary embodiments of the present invention, Figure 5 shows a signaling/process diagram illustrating various procedures according to exemplary embodiments of the present invention, and

Figure 6 shows a block diagram illustrating exemplary apparatuses according to exemplary embodiments of the present invention .

Description of exemplary embodiments

Exemplary aspects of the present invention will be described herein below. More specifically, exemplary aspects of the present are described hereinafter with reference to

particular non-limiting examples and to what are presently considered to be conceivable embodiments of the present invention. A person skilled in the art will appreciate that the invention is by no means limited to these examples, and may be more broadly applied.

It is to be noted that the following exemplary description mainly refers to specifications being used as non-limiting examples for certain exemplary network configurations and deployments. Namely, the present invention and its

embodiments are mainly described in relation to 3GPP

specifications (including LTE and LTE-A) being used as non- limiting examples for certain exemplary network

configurations and deployments . As such, the description of exemplary aspects and embodiments given herein specifically refers to terminology which is directly related thereto. Such terminology is only used in the context of the presented non- limiting examples, and does naturally not limit the invention in any way. Rather, any other communication systems, network configurations or system deployments, etc. may also be utilized as long as compliant with the features described herein .

Hereinafter, various embodiments and implementations of the present invention and its aspects or embodiments are

described using several alternatives. It is generally noted that, according to certain needs and constraints, all of the described alternatives may be provided alone or in any conceivable combination (also including combinations of individual features of the various alternatives) .

According to exemplary embodiments of the present invention, in general terms, there are provided mechanisms, measures and means for enhancing a radio access network, particularly in terms of a joint coordinated multipoint signal processing (JCoMP) for a plurality of (radio) cells constituting a cooperation area.

Figure 4 shows a schematic diagram of a multicasting scenario for a joint coordinated multipoint signal processing on the basis of an enhanced radio access network architecture according to exemplary embodiments of the present invention.

In Figure 4, it is exemplarily assumed that a radio access network (RAN) is constituted by seven cells each being served by a base station (BS) and a central unit (CU), and a core network (CN) is constituted by a serving gateway (S-GW) for handling user plane traffic (u-plane) for the RAN (while a mobility management entity (MME) for handling control plane (c-plane) traffic for the RAN in the CN is not illustrated) . The radio access network according to Figure 4 is for example an E-UTRAN.

It is noted that the number of seven cells or base stations (BS) assumed to constitute a relevant cooperation area according to Figure 4 is a non-limiting example only, and the relevant cooperation area may be constituted by any number of cells or base stations (BS) .

According to exemplary embodiments of the present invention, the central unit (CU) represents a network element which provides a central functionality with respect to a

cooperation area constituted by a plurality of (neighboring) cells. Stated in other words, the central unit (CU) provides for a central functionality for enhanced radio processing in terms of a joint coordinated multipoint signal processing for a plurality of (neighboring) cells constituting a cooperation area. Accordingly, the central unit (CU) could also be referred to as joint cooperation element or the like.

According to exemplary embodiments of the present invention, the central unit (CU) is featured in that it does not serve a (radio) cell or users therein, as is the case e.g. for an eNB, DeNB or the like. Rather, the central unit (CU)

according to exemplary embodiments of the present invention represents a network element or function which is considered by the CN (i.e. the S-GW) as a single base station (which could be regarded as representing a radio cell with zero radius), acting as a proxy between the CN (i.e. the S-GW) and the UE in each cell. Accordingly, from a CN point of view, all cells spanned by the eNBs in the cooperation area are considered to be cells spanned by the CU, i.e. the CU is transparent for the CN . According to exemplary embodiments of the present invention, the central unit (CU) is featured in that it represents a network element or function which forms a sub-network of (radio) bases stations, i.e. (radio) access node,

constituting the cooperation area. The (radio) base stations, i.e. (radio) access nodes, which are illustrated by BS in Figure 4, could comprise any one of eNBs, RNs (with single hop deployment and/or multi hop deployment), HeNBs (also referred to as femto nodes), pico nodes, and any combination of the mentioned nodes.

According to exemplary embodiments of the present invention, the central unit (CU) is capable of receiving UE-specific u- plane traffic for all BSs from the CN (i.e. the S-GW) , and (managing as well as) passing on the UE-specific u-plane traffic to the BSs in the cooperation area by way of

multicasting (as illustrated by solid lines in Figure 4) . Hence, the central unit (CU) according to exemplary

embodiments of the present invention is capable of performing joint coordinated multipoint signal processing based thereon and providing the results and/or resulting instructions to the BSs in the cooperation area.

According to exemplary embodiments of the present invention, the central unit (CU) is capable of receiving user-related (coordination) information (i.e. information on behalf of all users served by the BSs), which is exemplarily illustrated as channel state information (CSI), from one or more of the BSs, and (managing as well as) passing on the user- related ( coordination ) information, which is exemplarily illustrated as channel state information (CSI), to the

(other) BSs in the cooperation area by way of multicasting (as illustrated by dashed lines in Figure 4) . Hence, the central unit (CU) according to exemplary embodiments of the present invention is capable of performing joint coordinated multipoint signal processing based thereon and providing the results and/or resulting instructions to the BSs in the cooperation area.

In view of the above, joint coordinated multipoint signal processing at the central unit (CU) according to exemplary embodiments of the present invention may be based on the UE- specific u-plane traffic and/or the user-related

(coordination) information.

Accordingly, the central unit (CU) according to exemplary embodiments of the present invention is capable of performing joint coordinated multipoint signal processing for a

plurality of (radio) cells constituting a cooperation area.

Namely, as u-plane information for all BSs in the cooperation area served by the CU is arriving at the CU, an enhanced radio-related processing could be performed. For example, enhanced radio processing as envisaged for and described in the ARTIST4G project of the European Commission could be performed by the central unit (CU) according to exemplary embodiments of the present invention. This may include any advanced signal processing techniques, scheduling and cross layer design techniques and interference avoidance techniques (particularly but not exclusively those requiring cooperation with user plane exchange), as set forth in the ARTIST4G document "Definitions and architecture requirements for supporting interference avoidance techniques", Deliverable Dl .1.

Accordingly, exemplary embodiments of the present invention are specifically applicable for the requirements of the ARTIST4G project in that the central unit (CU) enables that u-plane information is available not only in a node serving a subject user, but also in neighboring nodes of a cooperation area, thereby facilitating a number of technigues such as to reduce and manage interference in LTE systems . Namely, the central unit (CU) according to exemplary embodiments of the present invention represents a reguired node or element to have access to user plane traffic of other BSs in the cooperation area.

Further, joint coordinated multipoint signal processing at the central unit (CU) according to exemplary embodiments of the present invention ma comprise radio interface related processing e.g. based on the user-related (coordination) information .

In view of the above, the central unit (CU) according to exemplary embodiments of the present invention is capable of accomplishing a multicast capability of user (and control) data for efficient data distribution to enable cooperative schemes .

According to exemplary embodiments of the present invention, the central unit (CU) is capable of acting as any one of an element to manage and multicast user-related coordination (e.g. CSI) information, an element to manage and multicast user plane

information, an element to manage and execute sub-network-specific SON algorithms, a X2 interface concentrator to mesh BS and CU elements and to manage information distribution within the subnetwork, an element acting as virtual handover target cell, to allow the delivery of user-related data to the CU, an anchor element to manage moving relays or the like, and/or

- a local breakout interface for sub-networks, comprised by a multitude of (small) cells, which are private networks or the like .

For example, an enhanced RAN (e.g. E-UTRAN) architecture according to exemplary embodiments of the present invention may be based on an E-UTRAN architecture supporting relaying, as illustrated in Figure 2. Accordingly, such approach allows to introduce a central unit (CU) in a CN-transparent manner, assuming that the CN is supporting the relaying concept. In such approach, the DeNB could be considered as additionally providing the functionalities of the central unit (CU) realizing a central functionality for enhanced radio

processing in terms of a joint coordinated multipoint signal processing for a plurality of (neighboring) cells

constituting a cooperation area, as outlined above.

As compared to the specified E-UTRAN architecture supporting relaying, the enhanced RAN (e.g. E-UTRAN) architecture according to exemplary embodiments of the present invention exemplarily differs in that: the central unit (CU) formally represents a (radio) cell of its own with zero radius,

a connection between CU and BSs in the cooperation area is not using the Un interface (as introduced between DeNB and RN for the LTE relay case) but rather an appropriate network connection such as for example a fixed (wire- based) network, the BSs in the cooperation area need not connect to the CU using the phased approach as specified for RNs, and conseguently the CU needs not to host UE capabilities like the DeNB,

the SI interface may be proxied at the CU or passed transparently, e.g. switching at layer 2, and

u-plane traffic becomes accessible for further

processing at the CU (while this access could be done in a fully transparent way e.g. by using technigues for eavesdropping, a mediation between the two independent legs (i.e. between CN and CU and between CU and BSs) may be accomplished by certain interference avoidance technigues or the like) .

For example, an enhanced RAN (e.g. E-UTRAN) architecture according to exemplary embodiments of the present invention may be based on an E-UTRAN architecture supporting home access (i.e. HeNBs), as illustrated in Figure 3. Accordingly, such approach allows to introduce a CU in a CN-transparent manner, assuming that the CN is supporting the home access concept. In such approach, the HeNB-GW could be considered as additionally providing the functionalities of the central unit (CU) realizing a central functionality for enhanced radio processing in terms of a joint coordinated multipoint signal processing for a plurality of (neighboring) cells constituting a cooperation area, as outlined above.

As compared to the specified E-UTRAN architecture supporting home access, the enhanced RAN (e.g. E-UTRAN) architecture according to exemplary embodiments of the present invention exemplarily differs in that: the Sl-U interface passes via the HeNB-GW to allow processing for interference avoidance technigues or the like, and

HeNBs served by the HeNB-GW span more than one cell, whereas a HeNB is currently allowed to support a single cell only (although there are current to allow an HeNB to support multiple cells) .

In view of the above, it is noted that considering the central unit (CU) according to exemplary embodiments of the present invention as a MME would fall short, as by definition an MME acts only on the control plane. Furthermore, the X2 interface between BSs (in particular, eNBs) served by different MMEs (in different MME pools) is not to be used for handover, but SI handover would have to be used instead.

It is also noted that, according to exemplary embodiments of the present invention, no modifications at the CN including CN protocols are reguired.

According to exemplary embodiments of the present invention, the central unit (CU) may be realized as a stand-alone element or may be co-located with an element or node of the core network. The CU function may also be integrated in a base station or radio access node (e.g. an eNB) or the like of the radio access network, assuming that the proxy function of the CU has a sufficient capacity or provisioning to serve the entire sub-network of the cooperation area. The

introduction of a stand-alone CU would allow to substitute elements like a femto gateway, a relay-specific proxy function, or the like by a generic network element or function, which on top allows any one of the management of CSI data or the like to enable cooperative schemes and the introduction of a multicast capability of user (and control) data for efficient data distribution to enable cooperative schemes. Beside any cooperation, a multicast capability in sub-networks such as those of cooperation areas allows innovative solutions to distribute user group oriented data with identical content, e.g. for a social network type of traffic emerging from popular services like Twitter,

Facebook, etc.

In the following, exemplary embodiments of the present invention are described with reference to methods, procedures and functions .

Figure 5 shows a signaling/process diagram illustrating various procedures according to exemplary embodiments of the present invention.

In Figure 5, it is exemplarily assumed that an enhanced RAN (e.g. E-UTRAN) architecture according to exemplary

embodiments of the present invention comprises a central unit (CU) being connected with a S-GW of the CN and three cells each being served by a base station (BS) . It is noted that the number of three cells or base stations (BS) assumed to constitute a relevant cooperation area is a non-limiting example only, and the relevant cooperation area may be constituted by any number of cells or base stations (BS) .

It is noted that the number of procedures illustrated in Figure 5 represents a non-limiting example only, and may deviate from this exemplary illustration. For example, exemplary embodiments of the present invention may comprise procedures relating to one or two (instead of all) of the distinct management procedures . Further, it is noted that the sequence of procedures

illustrated in Figure 5 represents a non-limiting example only, and may deviate from this exemplary illustration. For example, the coordination information may be received at the CU at the same time as or prior to the u-plane traffic, performing of the distinct management procedures may be different (as long as the relevant data is already received) , the distinct transmissions from the CU to the BSs may be different or combined in any conceivable manner, and so on.

As evident from the above description in connection with the exemplary illustration of procedures according to Figure 5, exemplary embodiments of the present invention may comprise the following methods, procedures and functions.

Methods, procedures and functions, which are operable at the S-GW, may comprise sending u-plane traffic for all BSs of a cooperation area to the CU.

Generally, the CU may provide a central functionality with respect to a cooperation area constituted by a plurality of (neighboring) cells, i.e. a central functionality for enhanced radio processing in terms of a joint coordinated multipoint signal processing for the plurality of

(neighboring) cells constituting the cooperation area.

Thereby, the CU may not serve a (radio) cell or users therein, but rather the CU may provide a network element or function which is considered by the CN as a single base station acting as a proxy between the CN and the UE in each cell, thus being transparent for the C . Methods, procedures and functions, which are operable at the CU, may comprise:

receiving u-plane traffic for all BSs of a cooperation area from the S-GW, and/or

- receiving coordination information (e.g. CSI) of one or more of the BSs of the cooperation area from the respective BS, respectively, and/or performing management (i.e. managing) the received u- plane traffic for all BSs of the cooperation area, and transmitting the (managed) u-plane traffic for all BSs to the respective BS of the BSs of the cooperation area, respectively, and/or performing management (i.e. managing) the received coordination information (e.g. CSI) of one or more of the BSs of the cooperation area, and transmitting the

(managed) coordination information (e.g. CSI) to the respective BS of the BSs of the cooperation area, respectively, and/or performing joint coordinated multipoint signal

processing (JCoMP) based on the received u-plane traffic for all BSs of the cooperation area and/or the

coordination information (e.g. CSI) of one or more of the BSs of the cooperation area, and transmitting the result of the JCoMP (e.g. including one or more

instructions or data) to the respective BS of the BSs of the cooperation area, respectively, and/or performing a functionality of one or more of managing and executing sub-network-specific SON algorithms, executing X2 interface concentration, acting as virtual handover target cell, acting as an anchor element to manage moving relays or the like, and/or acting as a local breakout interface for sub-networks. Methods, procedures and functions, which are operable at any one of the BSs of a cooperation area, may comprise:

transmitting coordination information (e.g. CSI) of the BS to the CU, and/or

- receiving (managed) u-plane traffic for the BS from the

CU, and/or receiving (managed) coordination information (e.g. CSI) for the BS from the CU, and/or receiving the result of joint coordinated multipoint signal processing (JCoMP) for the BS (e.g. including one or more instructions or data) from the CU, and/or applying any one of the received data (including u-plane traffic and/or coordination information and/or JCoMP result) accordingly.

In the following, exemplary embodiments of the present invention are described with reference to structural

arrangements and configurations of respective apparatuses, network nodes and systems, including both software and/or hardware thereof.

Respective exemplary embodiments of the present invention are described below referring to Figure 6, while for the sake of brevity reference is made to the detailed description of corresponding functional and/or structural properties according to Figure 4 and 5.

In Figure 6 below, which is noted to represent a simplified block diagram, the solid line blocks are basically configured to perform respective operations as described above. The entirety of solid line blocks are basically configured to perform the methods and operations as described above, respectively. With respect to Figure 6, it is to be noted that the individual blocks are meant to illustrate respective functional blocks implementing a respective function, process or procedure, respectively. Such functional blocks are implementation-independent, i.e. may be implemented by means of any kind of hardware or software, respectively. The arrows and lines interconnecting individual blocks are meant to illustrate an operational coupling there-between, which may be a physical and/or logical coupling, which on the one hand is implementation-independent (e.g. wired or wireless) and on the other hand may also comprise an arbitrary number of intermediary functional entities not shown. The direction of arrow is meant to illustrate the direction in which certain operations are performed and/or the direction in which certain data is transferred.

Further, in Figure 6, only those functional blocks are illustrated, which relate to any one of the above-described methods, procedures and functions. A skilled person will acknowledge the presence of any other conventional functional blocks reguired for an operation of respective structural arrangements, such as e.g. a power supply, a central

processing unit, respective memories or the like. Among others, memories are provided for storing programs or program instructions for controlling the individual functional entities to operate as described herein.

In view of the above, the thus described apparatuses 10 to 30 are suitable for use in practicing the exemplary embodiments of the present invention, as described herein. The thus described apparatus 10 may represent a (part of a) central unit, as described above. The thus described apparatus 20 may represent a (part of a) base station, as described above. The thus described apparatus 30 may represent a (part of a) serving gateway or a corresponding core network element or node, as described above.

As shown in Figure 6, according to exemplary embodiments of the present invention, a central unit 10 comprises a

processor 11, a memory 12, and an interface 13, which are connected by a bus 14 or the like, a base station 20

comprises a processor 21, a memory 22, and an interface 23, which are connected by a bus 24 or the like, and a serving gateway 30 or the like comprises a processor 31, a memory 32, and an interface 33, which are connected by a bus 34 or the like. The central unit is connected to the serving gateway 30 or the like through a link or connection 200, and the central unit is connected to one or more base station 20 of a cooperation area through a link or connection 100.

The memories 12, 22 and 32 may store respective programs assumed to include program instructions that, when executed by the associated processors 11, 21 and 31, enable the respective electronic device or apparatus to operate in accordance with the exemplary embodiments of the present invention. The processors 11, 21 and 31 and/or the interfaces 13, 23 and 33 may also include a modem or the like to facilitate communication over the (hardwire or wireless) links 100 and 200, respectively. The interfaces 13, 23 and 33 may include a suitable transceiver coupled to one or more antennas or communication means for (hardwire or wireless) communications with the linked or connected device (s), respectively. The interfaces 13, 23 and 33 are generally configured to communicate with another apparatus, i.e. the interface thereof.

In general terms, the respective devices /apparatuses (and/or parts thereof) may represent means for performing respective operations and/or exhibiting respective functionalities, and/or the respective devices (and/or parts thereof) may have functions for performing respective operations and/or exhibiting respective functionalities .

As evident from the above description in connection with the exemplary illustration of procedures according to Figure 6, exemplary embodiments of the present invention may comprise the following structural/functional arrangements and

configurations of respective apparatuses, network nodes and systems .

When subseguently referring to one of the S-GW, the CU and the BS, such reference is construed to be eguivalent to a reference to respective constituents thereof, particularly the processor in cooperation with the memory and/or the interface, respectively. The respective apparatus may comprise at least one interface configured for communication with at least another apparatus, at least one memory

configured to store computer program code, and at least one processor, wherein the at least one processor with the computer program code may be configured to cause the

apparatus to realize the respective functionality.

The S-GW may be configured (or may comprise means for functioning or comprise processor functionalities) to send u- plane traffic for all BSs of a cooperation area to the CU . Generally, the CU may be configured to provide a central functionality with respect to a cooperation area constituted by a plurality of (neighboring) cells, i.e. a central functionality for enhanced radio processing in terms of a joint coordinated multipoint signal processing for the plurality of (neighboring) cells constituting the cooperation area. Thereby, the CU may be configured to not serve a

(radio) cell or users therein, but rather the CU may be configured to provide a network element or function which is considered by the CN as a single base station acting as a proxy between the CN and the UE in each cell, thus being transparent for the C .

The CU may be configured (or may comprise means for

functioning or comprise processor functionalities) to receive u-plane traffic for all BSs of a cooperation area from the S-GW, and/or receive coordination information (e.g. CSI) of one more of the BSs of the cooperation area from the respective BS, respectively, and/or perform management (i.e. managing) the received u-plane traffic for all BSs of the cooperation area, and transmit the (managed) u-plane traffic for all BSs to the respective BS of the BSs of the cooperation area, respectively, and/or

perform management (i.e. managing) the received

coordination information (e.g. CSI) of one or more of the BSs of the cooperation area, and transmit the

(managed) coordination information (e.g. CSI) to the respective BS of the BSs of the cooperation area, respectively, and/or perform joint coordinated multipoint signal processing (JCoMP) based on the received u-plane traffic for all BSs of the cooperation area and/or the coordination information (e.g. CSI) of one or more of the BSs of the cooperation area, and transmit the result of the JCoMP

(e.g. including one or more instructions or data) to the respective BS of the BSs of the cooperation area, respectively, and/or

perform a functionality of one or more of managing and executing sub-network-specific SON algorithms, executing

X2 interface concentration, acting as virtual handover target cell, acting as an anchor element to manage moving relays or the like, and/or acting as a local breakout interface for sub-networks .

Any one of the BSs of a cooperation area may be configured (or may comprise means for functioning or comprise processor functionalities) to transmit coordination information (e.g. CSI) of the BS to the CU, and/or receive (managed) u-plane traffic for the BS from the CU, and/or receive (managed) coordination information (e.g. CSI) for the BS from the CU, and/or - receive the result of joint coordinated multipoint

signal processing (JCoMP) for the BS (e.g. including one or more instructions or data) from the CU, and/or apply any one of the received data (including u-plane traffic and/or coordination information and/or JCoMP result) accordingly. According to exemplarily embodiments of the present

invention, the processor 11 or 21 or 31, the memory 12 or 22 or 32 and the interface 13 or 23 or 33 may be implemented as individual modules, chipsets or the like, or one or more of them can be implemented as a common module, chipset or the like, respectively.

According to exemplarily embodiments of the present

invention, a system may comprise any conceivable combination of the thus depicted devices/apparatuses and other network elements, which are configured to cooperate as described above .

In general, it is to be noted that respective functional blocks or elements according to above-described aspects can be implemented by any known means, either in hardware and/or software, respectively, if it is only adapted to perform the described functions of the respective parts. The mentioned method steps can be realized in individual functional blocks or by individual devices, or one or more of the method steps can be realized in a single functional block or by a single device .

Generally, any method step is suitable to be implemented as software or by hardware without changing the idea of the present invention. Such software may be software code independent and can be specified using any known or future developed programming language, such as e.g. Java, C++, C, and Assembler, as long as the functionality defined by the method steps is preserved. Such hardware may be hardware type independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS (Metal Oxide Semiconductor), CMOS (Complementary MOS), BiMOS (Bipolar MOS), BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL (Transistor-Transistor Logic), etc., using for example ASIC (Application Specific IC (Integrated Circuit)) components, FPGA (Field-programmable Gate Arrays) components, CPLD (Complex Programmable Logic Device)

components or DSP (Digital Signal Processor) components. A device/apparatus may be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device/apparatus or module, instead of being hardware implemented, be implemented as software in a (software) module such as a computer program or a computer program product comprising executable software code portions for execution/being run on a processor. A device may be regarded as a device/apparatus or as an assembly of more than one device/apparatus, whether functionally in cooperation with each other or functionally independently of each other but in a same device housing, for example.

Apparatuses and/or means or parts thereof can be implemented as individual devices, but this does not exclude that they may be implemented in a distributed fashion throughout the system, as long as the functionality of the device is preserved. Such and similar principles are to be considered as known to a skilled person.

Software in the sense of the present description comprises software code as such comprising code means or portions or a computer program or a computer program product for performing the respective functions, as well as software (or a computer program or a computer program product) embodied on a tangible medium such as a computer-readable (storage) medium having stored thereon a respective data structure or code

means /portions or embodied in a signal or in a chip,

potentially during processing thereof. The present invention also covers any conceivable combination of method steps and operations described above, and any conceivable combination of nodes, apparatuses, modules or elements described above, as long as the above-described concepts of methodology and structural arrangement are applicable .

In view of the above, the present invention and/or exemplary embodiments thereof provide measures for an enhancement of a radio access network. Such measures may exemplarily comprise providing an enhanced RAN (e.g. E-UTRAN) architecture including a central functionality with respect to a

cooperation area constituted by a plurality of (neighboring) cell, wherein such central functionality may enable enhanced radio processing in terms of a joint coordinated multipoint signal processing for the plurality of (neighboring) cells constituting the cooperation area, and wherein such central functionality may represent a core network transparent proxy function between the core network and a user in each cell.

Even though the present invention and/or exemplary

embodiments are described above with reference to the examples according to the accompanying drawings, it is to be understood that they are not restricted thereto. Rather, it is apparent to those skilled in the art that the present invention can be modified in many ways without departing from the scope thereof, as evident from the above description.

List of acronyms and abbreviations

3GPP 3^r Generation Partnership Program

ARTIST4G Advanced Radio Interference Technologies for 4G Systems

BS Base Station

CN Core Network

CoMP Coordinated Multi-Point

CSI Channel State Information

DeNB Donor eNB

E-UTRAN Enhanced Universal Terrestrial Radio Access Network eNB evolved Node B (E-UTRAN base station)

GW Gateway

HeNB Home eNB JCoMP Joint Coordinated Multi-Point

LTE Long Term Evolution

LTE-A Long Term Evolution Advanced

MME Mobility Management Entity

RAN Radio Access Network RN Relay Node

S-GW Serving Gateway

SON Self Optimization Network

UE User Eguipment (aka mobile device)

Claims

1. A method for providing a group of access points in a communications network with user data comprising

receiving user plane data from a core network for user eguipments associated with any of the access points in the group,

receiving Radio Layer related coordination information from access points of the group,

deciding about processing and/or forwarding of the user plane data, and

transmitting user data to access points of the group.

2. The method according to claim 1, further comprising tansmitting of coordination information to the access points.

3. The method according to claim 1, further comprising acting as a proxy between the core network and user eguipments associated with the access points.

4. The method according to claim 3, further comprising acting as a virtual target cell for handover of the user eguipments .

5. The method according to claim 3, further comprising acting as an anchor element for moving access points.

6. The method according to claim 1, further comprising managing one or more sub-networks comprising one or more of the access points.

7. The method according to claim 6, further comprising managing and distributing of information within the subnetworks .

8. The method according to claim 6, further comprising managing and executing of algorithms for self optimization networks in the sub-networks .

9. The method according to claim 6, further comprising providing an interface for local breakout for the subnetworks .

10. The method according to any of the claims 1 to 9, further comprising transmitting user data for joint coordinated multipoint transmission to the access points,

wherein access points in the group of access points form a cooperative area for joint coordinated multipoint signal processing.

11. The method according to any of claims 1 to 10 wherein the communications network is an Enhanced Universal Terrestrial Radio Access Network.

12. A computer program product comprising code means for performing a method according to any of claims 1 to 11 when run on a processing means or module.

13. An apparatus for use in a communications network comprising

an interface unit configured to provide connection to a core network and connections to a group of access points, and a processor configured

to receive user plane data from the core network for user eguipments associated with any of the access points in the group, to receive Radio Layer related coordination information from the access points of the group,

to decide about processing and/or forwarding of the user plane data, and

to transmit user data to access points of the group.

14. The apparatus according to claim 13, further configured to transmit coordination information to the access points.

15. The apparatus according to claim 13, further configured to act as a proxy between the core network and user

eguipments associated with the access points.

16. The apparatus according to claim 15, further configured to act as an element of a virtual target cell for handover of the user eguipments .

17. The apparatus according to claim 15, further configured to act as an anchor element for moving access points.

18. The apparatus according to claim 13, further configured to manage one or more sub-networks comprising one or more of the access points.

19. The apparatus according to claim 18, further configured to manage and distribute information within the sub-networks .

20. The apparatus according to claim 18, further configured to manage and execute algorithms for self optimization networks in the sub-networks.

21. The apparatus according to claim 18, further configured to provide an interface for local breakout for the subnetworks .

22. The apparatus according to any of the claims 13 to 21, further configured to transmit user data for joint

coordinated multipoint transmission to the access points, wherein access points in the group of access points form a cooperative area for joint coordinated multipoint signal processing.

23. The apparatus according to any of claims 13 to 22, wherein the communications network is an Enhanced Universal Terrestrial Radio Access Network.

24. A method for providing a group of access points in a communications network with user data comprising

transmitting Radio Layer related coordination

information to a network element

wherein the network element is configured

to receive user plane data from the core network for user eguipments associated with any of the access points in the group,

to receive Radio Layer related coordination information from the access points of the group,

to decide about processing and/or forwarding of the user plane data, and

to transmit user data to access points of the group.

25. The method according to claim 24, further comprising receiving of coordination information from the network element .

26. The method according to claim 25, further comprising receiving user data for joint coordinated multipoint

transmission from the network element,

wherein access points in the group of access points form a cooperative area for joint coordinated multipoint signal processing .

27. The method according to claim 26, further comprising applying the received user data and the received coordination information for data transmission from an access point of the cooperative area configured for joint coordinated multipoint transmission .

28. The method according to claim 27 wherein the

communications network is an Enhanced Universal Terrestrial Radio Access Network.

29. A computer program product comprising code means for performing a method according to any of claims 24 to 28 when run on a processing means or module.

30. An apparatus for use in a communications network comprising

an interface unit configured to provide connection to a network element and a processor configured

to transmit Radio Layer related coordination information to the network element,

wherein the network element is configured

to receive Radio Layer related coordination information from the access points of the group, to decide about processing and/or forwarding of the user plane data, and

to transmit user data to access points of the group.

31. The apparatus according to claim 30, further configured to receive coordination information from the network element.

32. The apparatus according to claim 31, further configured to receive user data for joint coordinated multipoint transmission from the network element,

33. The apparatus according to claim 32, further configured to apply the received user data and the received coordination information for data transmission from an access point of the cooperative area configured for joint coordinated multipoint transmission .

34. The apparatus according to claim 33 wherein the