Causing beamforming at antenna site

Abstract

The disclosure relates to a method performed by radio equipment (RE) devices at an antenna site of causing beamforming towards a wireless device. The method comprises receiving, at a first RE device, a request to transmit data to said wireless device, and forwarding said request to a second RE device, acquiring first beamforming weights to be applied by the first RE device based on acquired first channel state information, acquiring second beamforming weights to be applied by the second RE device based on acquired second channel state information, receiving, at the first RE device, data to be transmitted and forwarding said data to the second RE device, applying the beamforming weights to the data by the first RE device and the second RE device, and transmitting the beamformed data to the wireless device from the first RE device over a first antenna and from the second RE device over a second antenna.

Description

CAUSING BEAMFORMING AT ANTENNA SITETECHNICAL FIELD

[0001] The present disclosure relates to a method performed by radio equipment devices at an antenna site of causing beamforming towards a primary sector wireless communication device served by the antenna site, and radio equipment devices performing the method. Further disclosed are computer programs and computer program products.BACKGROUND

[0002] Radio base stations are commonly installed at radio sites for sending data in downlink to wireless communication devices commonly refeed to as User Equipment (UE), and for receiving data from the UEs in uplink for further transport via a core network to e.g. a data network such as the Internet.

[0003] Such a core network may be embodied in the form of for instance a 3rdGeneration Partnership Project (3GPP) 5thgeneration core (5GC) network, in which case the radio base stations commonly are referred to as a gNodeBs (gNBs).

[0004] Communication between the part of the radio base station referred to as evolved Radio Equipment Control (eREC), sometimes referred to as Open Distributed Unit O-DU, and the part of the radio base station referred to as evolved Radio Equipment (eRE), sometimes referred to as Open Radio Unit O-RU, i.e. one or more radio units sending / receiving data to / from the UEs via antennas, occurs over a so-called switched fronthaul transport network.

[0005] In current communication systems, great amounts of both control and user plane data are transported over the switched fronthaul transport network of a gNB, thereby causing a high load in this transport network. Thus, it is desirable that the amount of data transported over the switched fronthaul transport network is decreased.SUMMARY

[0006] One objective is to solve, or at least mitigate, the problems in the art and thus to provide an approach of causing less load in the switched fronthaul transport network of a radio base station.

[0007] This objective is attained in a first aspect by a method performed by radio equipment (RE) devices at an antenna site of causing beamforming towards a primary sector wireless communication device served by the antenna site. The method comprises receiving, at a primary sector RE device, a request to transmit data to said wireless communication device, forwarding, from the primary sector RE device, said request to a secondary sector RE device, acquiring primary sector beamforming weights to be applied by the primary sector RE device for the requested data transmission based on acquired primary sector channel state information of said wireless communication device, acquiring secondary sector beamforming weights to be applied by the secondary sector RE device for the requested data transmission based on acquired secondary sector channel state information of said wireless communication device, receiving, at the primary sector RE device, data to be transmitted for the requested data transmission to said wireless communication device, forwarding, by the primary sector RE device to the secondary sector RE device, the data to be transmitted for the requested data transmission to said wireless communication device, applying the beamforming weights to the data requested to be transmitted by the primary sector RE device and the secondary sector RE device, wherein the primary sector RE device applies the primary sector beamforming weights to the data to be transmitted over a primary sector antenna while the secondary sector RE device applies the secondary sector beamforming weights to the data to be transmitted over a secondary sector antenna, and transmitting the beamformed data to the wireless communication device from the primary sector RE device over the primary sector antenna and from the secondary sector RE device over the secondary sector antenna.

[0008] This objective is attained in a second aspect by RE devices arranged at an antenna site and configured to cause beamforming towards a primary sector wireless communication device served by the antenna site, the RE devices each comprising a processing unit and a memory, said memory containing instructions executable by said processing unit, whereby the RE devices are operative to receive, at a primary sector RE device, a request to transmit data to said wireless communication device, forward, from the primary sector RE device, said request to a secondary sector RE device, acquire primary sector beamforming weights to be applied by the primary sector RE device for the requested data transmission based on acquired primary sector channel state information of said wireless communication device, acquiresecondary sector beamforming weights to be applied by the secondary sector RE device for the requested data transmission based on acquired secondary sector channel state information of said wireless communication device, receive, at the primary sector RE device, data to be transmitted for the requested data transmission to said wireless communication device, forward, by the primary sector RE device to the secondary sector RE device, the data to be transmitted for the requested data transmission to said wireless communication device, apply the beamforming weights to the data requested to be transmitted by the primary sector RE device and the secondary sector RE device, wherein the primary sector RE device applies the primary sector beamforming weights to the data to be transmitted over a primary sector antenna while the secondary sector RE device applies the secondary sector beamforming weights to the data to be transmitted over a secondary sector antenna, and to transmit the beamformed data to the wireless communication device from the primary sector RE device over the primary sector antenna and from the secondary sector RE device over the secondary sector antenna.

[0009] Advantageously, rather than burdening the switched fronthaul transport network with carrying information and data intended for the secondary RE device, the primary RE device will receive said information and data and forward required parts of it to the secondary RE device, which approach will decrease the amount of data sent over the switched fronthaul transport network

[0010] In an embodiment, the receiving at the primary RE device and the receiving at the secondary RE device is from a radio equipment control (REC) device.

[0011] In an embodiment, the acquiring of the beamforming weights is performed by the primary sector RE device computing the primary sector beamforming weights and the secondary sector RE device computing the secondary sector beamforming weights.

[0012] In an embodiment, the acquiring of the beamforming weights is performed by a central antenna site processing unit computing the beamforming weights based on acquired primary sector channel state information and secondary sector channel state information of said wireless communication device, which central antenna site processing unit supplies the computed beamforming weights to the primary sector RE device and the secondary sector RE device.

[0013] In an embodiment, the method further comprises transforming the beamformed data from a frequency domain representation to a time domain presentation before transmitting the beamformed data to the wireless communication device.

[0014] In an embodiment, the method further comprises suppressing, by the secondary sector RE device as instructed by the REC device, interference towards the wireless communication device for which the data transmission is requested by utilizing the secondary sector beamforming weights, if the secondary sector RE has data for transmission to one or more wireless communication devices on a same frequency as that allocated for the wireless communication device for which the data transmission is requested, which data to be transmitted to said one or more wireless communication devices is received from the REC device.

[0015] In an embodiment, the method further comprises receiving, at the primary sector RE device from the REC device, a request to acquire CSI for said wireless communication device, forwarding, from the primary sector RE device, said request to the secondary sector RE device, acquiring, at the primary sector RE device, channel state information of the wireless communication device to which transmission of data is requested based on Sounding Reference Signal (SRS) measurements performed with said wireless communication device, and acquiring, at the secondary sector RE device, channel state information of the wireless communication device to which transmission of data is requested based on SRS measurements performed with said wireless communication device.

[0016] In an embodiment, the respective acquired channel state information being is stored at the primary sector RE device and the secondary sector RE device.

[0017] In an embodiment, the respective acquired channel state information being stored at the central antenna site processing unit.

[0018] In an embodiment, the method further comprises acquiring, at the primary sector RE device, the acquired channel state information of the secondary sector RE device, and sending the acquired channel state information of the primary sector RE device and the secondary sector RE device to the REC device.

[0019] In an embodiment, the method further comprises sending the acquired channel state information of the primary sector RE device and the secondary sector RE device from each respective RE device to the REC device.

[0020] In a third aspect, a computer program is provided comprising computerexecutable instructions for causing the primary RE device to perform steps recited in the method of the first aspect when the computer-executable instructions are executed on a processing unit included in the primary RE device.

[0021] In a fourth aspect, a computer program product is provided comprising a computer readable medium, the computer readable medium having the computer program according to the third aspect embodied thereon.

[0022] In a fifth aspect, a computer program is provided comprising computerexecutable instructions for causing the secondary RE device to perform steps recited in the method of the first aspect when the computer-executable instructions are executed on a processing unit included in the secondary RE device.

[0023] In a sixth aspect, a computer program product is provided comprising a computer readable medium, the computer readable medium having the computer program according to the fifth aspect embodied thereon.

[0024] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Aspects and embodiments are now described, by way of example, with reference to the accompanying drawings, in which:

[0026] Figure 1 illustrates a communication network in which embodiments may be implemented;

[0027] Figure 2 shows a scenario where interference is caused at an antenna site;

[0028] Figure 3 shows a scenario where joint transmission is applied at an antenna site;

[0029] Figure 4 illustrates a schematic diagram of eREs at an antenna site according to an embodiment;

[0030] Figure 5 shows a signalling diagram illustrating a method according to an embodiment;

[0031] Figure 6 illustrates a schematic diagram of eREs at an antenna site according to an embodiment;

[0032] Figure 7a shows a signalling diagram illustrating a method according to an embodiment;

[0033] Figure 7b shows a signalling diagram illustrating a method according to a further embodiment;

[0034] Figure 8 illustrates a schematic diagram of eREs at an antenna site according to an embodiment;

[0035] Figure 9 shows a signalling diagram illustrating a method according to an embodiment;

[0036] Figure 10 shows a signalling diagram illustrating a method according to an embodiment;

[0037] Figure 11 illustrates a primary eRE according to an embodiment;

[0038] Figure 12 illustrates a secondary eRE according to an embodiment; and

[0039] Figure 13 illustrates a network in which embodiments may be implemented.DETAILED DESCRIPTION

[0040] The aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown.

[0041] These aspects may, however, be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and to fully conveythe scope of all aspects of invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0042] Figure 1 illustrates a simplified version of a communication system where a set of devices no, 111, 112 in the form of User Equipment (UE), e.g. smart phones, tablets, desktops, gaming consoles, connected vehicles, Internet-of-Things (loT) devices, etc., are served by a network node which in this example is embodied in the form of a radio base station 113 (RBS). While not shown in Figure 1, another set of UEs may beserved by a network node in the form of a second RBS 123.

[0043] The network nodes 113, 123 maybe composed of multiple physically separate components (e.g., a NodeB component and a radio network controller (RNC) component, or a base transceiver station (BTS) component and a base station controller (BSC) component, etc.), which may each have their own respective components. In certain scenarios in which the network nodes 113, 123 comprise multiple separate components (e.g., BTS and BSC components), one or more of the separate components maybe shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network nodes 113, 123 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components maybe duplicated (e.g., separate memory for different RATs) and some components maybe reused (e.g., a same antenna maybe shared by different RATs). The network nodes 113, 123 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network nodes 113, 123, for example Global System for Mobile Communications (GSM), Wideband Code Division Multiple Access (WCDMA), Long Term Evolution (LTE), New Radio (NR), WiFi, Zigbee, Z-wave, Long Range Wide Area Network (LoRaWAN), Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies maybe integrated into the same or different chip or set of chips and other components within network nodes 113, 123. The network nodes 113, 123 will in the following be exemplified in the form of RBSs.

[0044] Each RBS 113, 123 is connected to a core network, such has e.g., a 3rd Generation Partnership Project (3GPP) 5thgeneration core (5GC) network. In a 5GC network, the radio base station is commonly referred to as a gNodeB (gNB).

[0045] Thus, Figure 1 specifically illustrates a gNB 113 capable of communicating with a neighbouring gNB 123 over an Xn interface. The gNBs 113, 123 form part of a RAN referred to as New Generation (NG) RAN.

[0046] The gNB 113 comprises a central unit (CU) being split into a CU-CP 231 (“control plane”) and a CU-UP 232 (“user plane”) being interconnected over an El interface. Control plane signal paths are illustrated with dotted lines while user plane signal paths are illustrated with continuous lines.

[0047] The CU-CP 232 connects to an Access and Mobility Function (AMF) 220 of the 5GC network over interface N2 carrying control plane signalling via Nil, a Session Management Function (SMF) 221 and N4 interface to User Plane Function (UPF) 210, while the CU-UP 231 connects to a data network 213, such as the Internet, over N6 via N3 interface and the UPF 210 for transporting user data.

[0048] As is well-known, the AMF 220 is configured to provide UE-based authentication, authorization, mobility management, etc., while the SMF 221 is configured to perform session management, e.g. session establishment, modify and release, etc., and the UPF 210 is a service function that processes user plane packets; processing may include altering the packet’s payload and / or header, interconnection to data network(s), packet routing and forwarding, etc.

[0049] Further, the CU-CP 232 connects to a distributed unit 233a (DU) via interface Fi-C and further to one or more of the UEs 110-112 via a so-called switched fronthaul transport network implementing a protocol referred to as evolved Common Public Radio Interface (eCPRI) and radio units 234a, 234b (RUs) communicating via antennas (not shown) over wireless interface Uu, while the CU-UP 231 connects to a DU 233b via interface Fi-U and further on to the UEs 110-112 via the switched fronthaul transport network (utilizing eCPRI), the RUs 234c, 234b and the wireless interface Uu.

[0050] Commonly, the functional entities of the gNB 113 upstream (i.e. towards the 5GC) of the switched fronthaul transport network are referred to as forming evolved Radio Equipment Control (eREC) while the RUs are referred to as evolved Radio Equipment (eRE). This terminology will be used in the following.

[0051] As is understood, the eREs 234a-234d and the antennas are typically mounted in an elevated position in a radio tower, while the eREC is located on the ground and connected to the tower-mounted eREs 234a-234d via fibre.

[0052] The eREC and the tower-mounted eREs and antennas are commonly referred to as forming an antenna site. Such antenna sites are shown in Figure 2 and 3 to be discussed in the following.

[0053] Figure 2 illustrates an example of an antenna site 300 comprising three eREs 2343-2340 with a respective antenna array 301, 302, 303 for transmitting and receiving radio signals. As is understood, each eRE 234a-c is controlled by the previously mentioned eREC (not shown in Figure 2) communicating with the eREs 234a-c over the switched fronthaul transport network. The illustrated system is referred to as a distributed multiple input multiple output (D-MIMO) system.

[0054] Assuming for instance that primary sector eRE 234a transmits data to first UE no as illustrated by first transmission path 311 and second transmission path 312, while transmitting data to second UE 111 as illustrated by third transmission path 313.

[0055] Assuming further that secondary sector eRE 302 transmits data in a fourth transmission path 314, which is not intended for the second UE 111, and thus as illustrated in Figure 2 causes interference to the second UE 111 which interference the eREC (not shown in Figure 2) controlling the antenna site 300 will attempt to cancel out, for example by means of controlling beamforming of the antenna array 302 of the secondary sector eRE 234b such that the data of the fourth transmission path 314 ideally does not reach the second UE 111, or at least only affects the second UE 111 to a small extent. In other words, interference cancellation (IC) will ideally be performed in downlink (DL). Further, the interference that the second UE 111 is subjected to can be mitigated by also controlling beamforming of the antenna array 301 of the primary sector eRE 234a to optimally direct the third transmission path 313 towards the second UE 111 for DL data transmission with higher signal-to-noise ratio (SNR).

[0056] Similarly, the third UE 112 receives data from its primary sector eRE 234b but also undesirably from a secondary sector eRE 234c, thereby causing interference to the second UE 112.

[0057] As is understood, the eREC will have to send any inference cancellation control signals intended for the secondary sector eRE 302 over the switched fronthaul transport network, thereby causing a great deal of control data traffic to be transported over the switched fronthaul transport network towards the secondary sector eRE 302.

[0058] Figure 3 illustrates the antenna site 300 but where a different approach is utilized. In this approach, so-called joint transmission is applied, where for instance data transmitted to the second UE 111 in DL is transmitted via both the primary sector RE 234a and the secondary sector RE 234b.

[0059] Thus, in this approach, data are transmitted in the DL to the same UE 111 from multiple sectors and combined at the UE 111 to attain signals having higher SNR. In joint transmission, the eREC controls coordinated multi-point transmission of the signal, in this case via both the primary sector eRE 234a and the secondary sector eRE 234b.

[0060] With respect to the switched fronthaul transport network connecting the eREC and the eREs, this approach is even more challenging, since not only must the appropriate control signals be transmitted by the eREC to the eREs for multi-point transmission coordination, but user plane data intended for the second UE 111 must be transmitted to both the primary sector eRE 234a and the secondary sector eRE 234b.

[0061] Now, with reference to Figures 2 and 3, a current issue upon implementing beamforming to cause interference cancellation or joint transmission is that the switched fronthaul transport network inevitably must carry a great amount of data traffic in downlink, including both control plane data and user plane data.

[0062] Figure 4 illustrates a schematic diagram of antenna site 300 comprising eREs 234a, 234b at an antenna site 300 according to an embodiment for resolving this issue utilizing joint transmission. Reference is further made to the signalling diagram flowchart of Figure 5 illustrating a corresponding method according to an embodiment.

[0063] As previously mentioned with reference to Figure 1, the functional entities of the gNB 113 upstream of the switched fronthaul transport network are referred to as forming the eREC, while the RUs are referred to as eREs. Reference numeral 320will be utilized to denote the eREC in Figures 4 and 5. In the following embodiments, it is assumed that the second UE 111 is the UE to which data is transmitted in the DL from the gNB 113.

[0064] Data transmission over a physical downlink shared channel (PDSCH) from the gNB 113 to the UE 111 can advantageously be improved within the antenna site 300 by using neighbouring sectors as joint transmission points for PDSCH data or by using neighbouring sectors for interference suppression. These two methods can be used selectively on the antenna site 300 based on e.g. UE position and / or intra-sector interference.

[0065] As will be described, the amount of data (and bitrate of the data) transported over the switched fronthaul transport network between the eREC 320 and the eREs 234a, 234b is advantageously reduced if instead the appropriate data is communicated between the eREs 234a, 234b of the antenna site 300 using for instance ethernet communication between the eREs or wireless communication over e.g. microwave .

[0066] Thus, in a first step S101, the eREC 320 will send a request, via the switched fronthaul transport network 321 using eCPRI, to the primary sector eRE 234a to transmit data to the UE 111. The request is transported via path indicated Ctrl (“control”). Advantageously, rather than having the eREC 320 also sending the request to the secondary sector eRE 234b as in the prior art, the primary sector eRE 234a forwards the request for data transmission to the secondary sector eRE 234b in S102 via antenna site network 322, which is a network between the eREs 234a, 234b of the antenna site 300, using e.g. Ethernet.

[0067] Now, in order to determine how the beamforming is to be performed at each eRE, channel state information (CSI) defining channel properties of the communication link from each eRE 234a, 234b to the UE 111 is required. Typically, the CSI is acquired by requesting the UE 111 to transmit a so-called Sounding Reference Signal (SRS) based on which the respective eRE 234a, 234b acquires the CSI. This will be described in more detail subsequently.

[0068] However, at this stage, it is assumed that both the primary sector eRE 234a and the secondary sector eRE 234b already have access to the CSI for the channel established between the UE 111 and the respective eRE.

[0069] Thereafter, the primary sector eRE 234a computes in 8103a beamforming weights, as indicated by functional entity DL IC (“downlink interference cancellation”) for the data transmission 313 to be performed via the primary sector antenna array 301 to the UE 111, based on the CSI acquired for the channel established between the primary sector eRE 234a and the UE 111.

[0070] Similarly, the secondary sector eRE 234b computes in 8104a beamforming weights for the data transmission 314 to be performed via the secondary sector antenna array 302 to the UE 111, based on the CSI acquired for the channel established between the secondary sector eRE 234b and the UE 111.

[0071] As is understood, in both the primary eRE 234a and the secondary eRE 234b, the beamforming weights are dependent on which transmission point (TP) is utilized for the respective (multi-transmission point) MIMO antenna array 301, 302, as indicated with the dashed-line boxes referred to as “UE TP 1” and UE TP 2”. In other words, as illustrated in Figure 3, the point referred to as UE TP 1 corresponds to the point at the primary antenna array 301 where the third transmission path 313 originates, while the point referred to as UE TP 2 corresponds to the point at the secondary antenna array 302 where the fourth transmission path 314 originates.

[0072] In S105, the eREC 320 sends the data to be transmitted to the UE 111 (indicated by path denoted “Data”) by the eREs 234a, 234b to the primary sector eRE 234a over the eCPRI transport network 321, which data the primary sector eRE 234a forwards over the antenna site network 322 to the secondary sector eRE 234b in S106.

[0073] This is advantageous, since the eCPRI transport network 321 is not burdened with also transporting the UE data to the secondary sector eRE 234b, as is the case in the prior art. Rather, the data to ultimately be transmitted by the secondary sector eRE 234b to the UE 111 is transported over the antenna site network 322 by the primary sector eRE 234a.

[0074] In S107, the primary sector eRE 234a applies the computed primary sector beamforming weights to the data to be transmitted via the primary sector antenna array 301 to the UE 111, as indicated by functional entity “Beamform”.

[0075] Similarly, the secondary sector eRE 234b applies in S108 the computed secondary sector beamforming weights to the data to be transmitted via the secondary sector antenna array 302 to the UE 111.

[0076] Finally, in steps S109 and S110, the beamformed data is sent from the primary sector eRE 234a and the secondary sector eRE 234b, respectively, to the UE 111 in a joint transmission.

[0077] In an embodiment, steps S109 and S110 include transforming the beamformed data from a frequency domain representation to a time domain presentation before transmitting the beamformed data to the wireless communication device, unless the beamformed data is processed in the time domain from the start.

[0078] Figure 6 illustrates a schematic diagram of an antenna site 300 according to another embodiment for resolving this issue utilizing coordinated interference suppression in addition to join transmission. Reference is further made to the signalling diagram of Figure 7a illustrating a corresponding method according to an embodiment.

[0079] Similar to Figure 5, in a first step S101, the eREC 320 will send a request, via the switched fronthaul transport network 321 using eCPRI, to the primary sector eRE 234a to transmit data to the UE 111. Advantageously, rather than having the eREC 320 also sending the request to the secondary sector eRE 234b as in the prior art, the primary sector eRE 234a forwards the request for data transmission to the secondary sector eRE 234b in S102 via antenna site network 322 using e.g. Ethernet. The request is transferred via the Ctrl path.

[0080] In addition, the eREC 320 also sends a transmission request using eCPRI to the secondary sector eRE 234b in Sioib to transmit data to UE 114.

[0081] Again, in order to determine how the beamforming is to be performed at each eRE, CSI defining channel properties of the communication link from each eRE 234a, 234b to the UE 111 is required. At this stage, it is assumed that both the primary sector eRE 234a and the secondary sector eRE 234b already have access to the CSI for the channel established between the UE 111 and the respective eRE.

[0082] Thereafter, the primary sector eRE 234a computes in 8103a beamforming weights for the data transmission 313 to be performed via the primary sector antennaarray 301 to the UE 111, based on the CSI acquired for the channel established between the primary sector eRE 234a and the UE 111.

[0083] Similarly, the secondary sector eRE 234b computes in 8104a beamforming weights for the data transmission 314 to be performed via the secondary sector antenna array 302 to the UE 111, based on the CSI acquired for the channel established between the secondary sector eRE 234b and the UE 111.

[0084] In S105, the eREC 320 sends the data to be transmitted to the UE 111 by the eREs 234a, 234b to the primary sector eRE 234a over the eCPRI transport network 321, the data being transported via the Data path, which data the primary sector eRE 234a forwards over the Ethernet network 322 to the secondary sector eRE 234b in S106.

[0085] In this embodiment, in addition to the embodiment described for the embodiment referring to Figures 4 and 5, if the secondary sector RE 234b has at least one UE to which data transmission is scheduled with the same frequency allocation as the UE 111 (in this embodiment said at least one UE is exemplified by UE 114 thus being served by eRE 234b as a primary sector eRE), the eREC 320 sends in 8105a over the eCPRI transport network 320 the data to be transmitted to UE 114 being allocated on the same frequency as the UE 111.

[0086] As previously described, in S107, the primary sector eRE 234a applies the computed primary sector beamforming weights to the data 313 to be transmitted via the primary sector antenna array 301 to the UE 111, as indicated by the Beamform entity.

[0087] Similarly, the secondary sector eRE 234b applies in S108 the computed secondary sector beamforming weights to the data 314 to be transmitted via the secondary sector antenna array 302 to the UE 111.

[0088] However, in this embodiment, in addition to what is described for the embodiment referring to Figures 4 and 5, the secondary sector eRE 234b will in Sio8a also apply suppression of interference caused by the data 315 intended for the UE 114 in a direction towards the UE 111, which data is received from the eREC 320, via the switched fronthaul transport network 321 (and hence not via the antenna site network 322), by taking into account the secondary sector beamforming weights computed in 8104a in response to receiving the transmission request for the UE 111 inS102. As is understood, interference suppression is well known in the art, whereby e.g. weight values in a matrix are modified such that a transmission point’s transmission beam direction is modified so that the beam interferes less with beams in another direction.

[0089] Finally, in steps S109 and S110, the beamformed data is sent from the primary sector eRE 234a and the secondary sector eRE 234b, respectively, to the UE 111 in a joint transmission, while in Sin the secondary sector eRE 234b sends data 315 to the UE 114 with interference suppression towards the UE 111.

[0090] Figure 7b shows a signalling diagram illustrating a variant of the method of Figure 7a. In Figure 7b, only suppression is undertaken and no joint transmission.

[0091] In Figure 7b, the method is identical up until step 8105a, where the secondary sector eRE 234a receives the data from the eREC 320 to be transmitted to the UE 114.

[0092] In this embodiment, since no joint transmission is to be performed but only suppression, the secondary sector eRE 234b will not send data to the UE 111 and thus no data is sent from the primary sector eRE 234a to the secondary sector eRE 234b, and step S106 of Figure 7a is thus omitted, as is the step of applying beamforming weights in S108 to data intended for UE 111.

[0093] Rather, as previously described, the primary sector eRE 234a applies in S107 the computed primary sector beamforming weights to the data 313 to be transmitted via the primary sector antenna array 301 to the UE 111, as indicated by the Beamform entity, while the secondary sector eRE 234b in Sio8a applies suppression of interference caused by the data 315 intended for the UE 114 in a direction towards the UE 111, which data is received from the eREC 320 via the switched fronthaul transport network 321 (and hence not via the antenna site network 322), by taking into account the secondary sector beamforming weights computed in 8104a in response to receiving the transmission request in S102.

[0094] Finally, in step S109, the beamformed data is sent from the primary sector eRE 234a to the UE 111, while in Sin the secondary sector eRE 234b sends data 315 to the UE 114 with interference suppression towards the UE 111. Thus, step S110 of Figure 7a is omitted since no joint transmission is performed in this embodiment.

[0095] In one embodiment a method is performed by radio equipment, RE, devices (234a, 234b) at an antenna site (300) of causing beamforming towards a primary sector wireless communication device (111) served by the antenna site (300), comprising: receiving (S101), at a primary sector RE device (234a), a request to transmit data to said wireless communication device (m);forwarding (S102), from the primary sector RE device (234a), said request to a secondary sector RE device (234b); acquiring (8103a, 8103c) primary sector tuning information to be applied by the primary sector RE device (234a) for the requested data transmission . The tuning information may be based on acquired primary sector channel state information of said wireless communication device (111). Tuning information may be beamforming weight, to set amplitude or phase or to set degree or direction of beams. The method further comprise acquiring (8104a, 8104c) secondary sector tuning information to be applied by the secondary sector RE device (234b) for the requested data transmission; receiving (S105), at the primary sector RE device (234a), data to be transmitted for the requested data transmission to said wireless communication device; forwarding (S106), by the primary sector RE device (234a) to the secondary sector RE device (234b), the data to be transmitted for the requested data transmission to said wireless communication device (111); applying (S107, S108) the primary tuning information to the data requested to be transmitted by the primary sector RE device (234a) over a primary sector antenna (301) and the secondary tuning information to the data requested to be transmitted by the secondary sector RE device (234b) over a secondary sector antenna (302); and transmitting (S109, S110) the beamformed data to the wireless communication device (111) from the primary sector RE device (234a) over the primary sector antenna (301) and from the secondary sector RE device (234b) over the secondary sector antenna (302) and suppressing (Sio8a), by the secondary sector RE device (234b) interference towards the wireless communication device (111) for which the data transmission is requested (S101) by utilizing the secondary sector tuning information. The suppressing maybe instructed (Sioib) by the REC device (320). The utilizing the secondary tuning information may be utilizing sector beamforming weights. The utilizing may occur if the secondary sector RE (234b) has data for transmission (Sin) to one or more wireless communication devices (114) on a same frequency as that allocated for the wireless communication device (111) for which the data transmission is requested(Sioi), which data to be transmitted to said one or more wireless communication devices (114) maybe received (8105a) from the REC device (320).

[0096] Figure 8 illustrates a schematic diagram of an antenna site 300 according to another embodiment for resolving the above-mentioned issue. Reference is further made to the signalling diagram of Figure 9 illustrating a corresponding method according to an embodiment.

[0097] As shown in Figure 8, the schematic diagram has similarities with that of Figure 6, however the beamforming weights are computed by a central antenna site processing unit 323 forming part of the antenna site network 322, to which the CSI of the primary sector eRE 234a and the secondary sector eRE 234b is supplied. The computed weight are then applied in the beamformer of the primary sector eRE 234a and the secondary sector eRE 234b, respectively.

[0098] Thus, in a first step S101, the eREC 320 will send a request, via the switched fronthaul transport network 321 using eCPRI, to the primary sector eRE 234a via the Ctrl path to transmit data to the UE 111. Advantageously, rather than having the eREC 320 also sending the request to the secondary sector eRE 234b as in the prior art, the primary sector eRE 234a forwards the request for data transmission to the secondary sector eRE 234b in S102 via antenna site network 322 using e.g. Ethernet.

[0099] Different from the embodiment of Figures 4 and 5, the primary sector eRE 234a sends a request in Si02a to the central antenna site processing unit 323 (denoted ASPU in Figure 9) to compute the beamforming weights. It is here assumed that the primary sector eRE 234a and the secondary sector eRE 234b already has supplied the central antenna site processing unit 323 with the appropriate CSI (i.e. at an earlier stage or in reply to the data transmission request of the eREC 320).

[0100] Thus, in response to the request in Si02a, the central antenna site processing unit 323 computes in 8103b beamforming weights for the data transmission 313 to be performed via the primary sector antenna array 301 to the UE 111, based on the CSI acquired for the channel established between the primary sector eRE 234a and the UE 111, and further computes in 8104b for the secondary sector eRE 234b beamforming weights for the data transmission 314 to be performed via thesecondary sector antenna array 302 to the UE 111, based on the CSI acquired for the channel established between the secondary sector eRE 234b and the UE 111.

[0101] The computed weights are then supplied to the primary sector eRE 234a and the secondary sector eRE 234b, respectively in steps S103C and S104C.Advantageously, this relieves the primary sector eRE 234a and the secondary sector eRE 234b from having to compute the weights.

[0102] In S105, the eREC 320 sends the data to be transmitted to the UE 111 by the eREs 234a, 234b (via Data path) to the primary sector eRE 234a over the eCPRI transport network 321, which data the primary sector eRE 234a forwards over the antenna site network 322 to the secondary sector eRE 234b in S106.

[0103] This is advantageous, since the eCPRI transport network 321 is not burdened with also transporting the UE data to the secondary sector eRE 234b, as is the case in the prior art. Rather, the data to ultimately be transmitted by the secondary sector eRE 234b to the UE 111 is transported over the antenna site network 322 by the primary sector eRE 234a.

[0104] In S107, the primary sector eRE 234a applies the computed primary sector beamforming weights to the data to be transmitted via the primary sector antenna array 301 to the UE 111 as indicated by the Beamform entity.

[0105] Similarly, the secondary sector eRE 234b applies in S108 the computed secondary sector beamforming weights to the data to be transmitted via the secondary sector antenna array 302 to the UE 111.

[0106] Finally, in steps S109 and S110, the beamformed data 313, 314 is sent from the primary sector eRE 234a and the secondary sector eRE 234b, respectively, to the UE 111.

[0107] As previously mentioned, the embodiments described hereinabove assumes that the appropriate CSI already is available at the primary sector eRE 234a and the secondary sector eRE 234b and / or the central antenna site processing unit 323-

[0108] Figure 10 shows a signalling diagram illustrating a method of acquiring CSI according to an embodiment.

[0109] In a first step S201, the eREC 320 requests the primary sector eRE 234a to acquire CSI for the UE 111 to which a data transmission is requested. As is understood, this CSI request maybe included with the data transmission request of S101 in Figures 5, 7 and 9.

[0110] This CSI request is forwarded by the primary sector eRE 234a to the secondary sector eRE 234b in S202 over the antenna site network 322.

[0111] The CSI may be acquired by having each of the primary sector eRE 234a and the secondary sector eRE 234b request the UE 111 to transmit a Sounding Reference Signal (SRS) on which the eREs 234a, 234b performs measurements to determine the CSI which may reflect the condition of the respective channel under the effect of e.g. scattering, fading, delay distortion, power decay, and multipath effect with distance. Thereafter, the CSI is acquired in 8204a, 8204b from the performed SRS measurements. Advantageously, by having the primary sector eRE 234a forward the CSI request to the secondary sector eRE 234b, transmission over the fronthaul transport network of the CSI request from the eREC 320 to the secondary sector eRE2 234b is avoided.

[0112] In an optional embodiment, the CSIs for the primary sector and secondary sector are stored in 8205a and 8205b at the primary sector eRE 234a and the secondary sector eRE 234b for subsequently being used for beamforming.

[0113] As is understood, in a scenario where the central antenna site processing unit 323 is utilized as illustrated in Figure 8, the primary sector CSI and secondary sector CSI are transferred via the antenna site network 322 for storage at the central antenna site processing unit 323.

[0114] In an embodiment, the CSI of the secondary sector is sent from the secondary sector eRE 234b in S206 over the antenna site network 322 to the primary sector eRE 234a, and the primary sector eRE 234a forwards the primary sector CSI and the secondary sector CSI to the eREC 320 in S207 over the transport network 321.

[0115] Alternatively, each of the primary sector eRE 234a and the secondary sector eRE 234b forwards the respective CSI to the eREC 320, in which case the secondary sector CSI is not necessarily sent to the primary sector eRE 234a.

[0116] Figure 11 illustrates a primary sector eRE 234a configured to cause beamforming towards a UE according to an embodiment. The steps of the method performed by the primary sector eRE 234a are in practice performed by a processing unit 411 embodied in the form of one or more microprocessors arranged to execute a computer program 412 downloaded to a storage medium 413 associated with the microprocessor, such as a Random Access Memory (RAM), a Flash memory or a hard disk drive. The processing unit 411 is arranged to cause the primary sector eRE 234a to carry out the method according to embodiments when the appropriate computer program 412 comprising computer-executable instructions is downloaded to the storage medium 413 and executed by the processing unit 411. The storage medium 413 may also be a computer program product comprising the computer program 412. Alternatively, the computer program 412 maybe transferred to the storage medium 413 by means of a suitable computer program product, such as a Digital Versatile Disc (DVD) or a memory stick. As a further alternative, the computer program 412 maybe downloaded to the storage medium 413 over a network. The processing unit 411 may alternatively be embodied in the form of a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), etc. The primary sector eRE 234a further comprises a communication interface 414 (wired or wireless) over which it is configured to transmit and receive data.

[0117] Figure 12 illustrates a secondary sector eRE 234b configured to cause beamforming towards a UE according to an embodiment. The steps of the method performed by the secondary sector eRE 234b are in practice performed by a processing unit 511 embodied in the form of one or more microprocessors arranged to execute a computer program 512 downloaded to a storage medium 513 associated with the microprocessor, such as a RAM, a Flash memory or a hard disk drive. The processing unit 511 is arranged to cause the secondary sector eRE 234b to carry out the method according to embodiments when the appropriate computer program 512 comprising computer-executable instructions is downloaded to the storage medium 513 and executed by the processing unit 511. The storage medium 513 may also be a computer program product comprising the computer program 512. Alternatively, the computer program 512 maybe transferred to the storage medium 513 by means of a suitable computer program product, such as a DVD or a memory stick. As a further alternative, the computer program 512 maybe downloaded to the storage medium513 over a network. The processing unit 511 may alternatively be embodied in the form of a DSP, an ASIC, an FPGA, a CPLD, etc. The secondary sector eRE 234b further comprises a communication interface 514 (wired or wireless) over which it is configured to transmit and receive data.

[0118] The primary sector eRE 234a and the secondary sector eRE 234b according to embodiments may be provided as a standalone device or as a part of at least one further device. Alternatively, functionality of the eREs 234a, 234b maybe distributed between at least two devices, or nodes. These at least two nodes, or devices, may either be part of the same network part or may be spread between at least two such network parts. In general terms, instructions that are required to be performed in real time may be performed in a device, or node, operatively closer to a radio cell than instructions that are not required to be performed in real time.

[0119] Thus, a first portion of the instructions performed by the eREs 234a, 234b may be executed in a first device, and a second portion of the of the instructions may be executed in a second device; the herein disclosed embodiments are not limited to any particular number of devices on which the instructions performed by the eREs 234a, 234b maybe executed.

[0120] Hence, the methods according to the herein disclosed embodiments are suitable to be performed by a device residing in a cloud computational environment. Therefore, although a single processing circuitry 810 is illustrated in Figure 8, the processing circuitry 810 maybe distributed among a plurality of devices, or nodes.

[0121] Figure 12 illustrates a network in the form of an Open RAN 100 (O-RAN), in which embodiments may be implemented.

[0122] With reference to the O-RAN 100, the role of a Non-Real Time RAN intelligent controller (RIC) 200 is among other things, such as providing a service management and orchestration framework, to serve one or more radio base stations 350 (i.e. RAN sites) referred to as O-eNB via 01 interface and to provide high-level control signals to Near-Real Time RICs 400 via Al interface; such signals include but not limited to policy-based guidance, machine-learning (ML) model management, and enrichment of data. The role of Near-Real Time RICs 400 is to perform low-level control signals to O-RAN compatible network elements including the one or more O- eNBs 350, O-CU-CP 500, O-CU-UP 600 and 0-DU 700, i.e. eREC, via E2 interface.Further included is an O-RU 800, i.e. eRE, connected to the O-DU 700 via a control, user and synchronization (CUS) plane as well as via a management (M) plane, and an O-Cloud 900, i.e. a cloud platform.

[0123] The aspects of the present disclosure have mainly been described above with reference to a few embodiments and examples thereof. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.

[0124] Thus, while various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

CLAIMS i. A method performed by radio equipment, RE, devices (234a, 234b) at an antenna site (300) of causing beamforming towards a primary sector wireless communication device (111) served by the antenna site (300), comprising: receiving (S101), at a primary sector RE device (234a), a request to transmit data to said wireless communication device (111); forwarding (S102), from the primary sector RE device (234a), said request to a secondary sector RE device (234b); acquiring (8103a, 8103c) primary sector beamforming weights to be applied by the primary sector RE device (234a) for the requested data transmission based on acquired primary sector channel state information of said wireless communication device (111); acquiring (8104a, 8104c) secondary sector beamforming weights to be applied by the secondary sector RE device (234b) for the requested data transmission based on acquired secondary sector channel state information of said wireless communication device (111); receiving (S105), at the primary sector RE device (234a), data to be transmitted for the requested data transmission to said wireless communication device; forwarding (S106), by the primary sector RE device (234a) to the secondary sector RE device (234b), the data to be transmitted for the requested data transmission to said wireless communication device (111); applying (S107, S108) the beamforming weights to the data requested to be transmitted by the primary sector RE device (234a) and the secondary sector RE device (234b), wherein the primary sector RE device (234a) applies (S107) the primary sector beamforming weights to the data to be transmitted over a primary sector antenna (301) while the secondary sector RE device (234b) applies (S108) the secondary sector beamforming weights to the data to be transmitted over a secondary sector antenna (302); and transmitting (S109, S110) the beamformed data to the wireless communication device (111) from the primary sector RE device (234a) over the primary sector antenna (301) and from the secondary sector RE device (234b) over the secondary sector antenna (302)..

2. The method of claim 1, wherein the acquiring (8103a, 8104a) of the beamforming weights is performed by the primary sector RE device (234a) computing (8103a) the primary sector beamforming weights and the secondary sector RE device (234b) computing (8104a) the secondary sector beamforming weights.

3. The method of claim 1, wherein the acquiring (S103C, 8104c) of the beamforming weights is performed by a central antenna site processing unit (323) computing (8103b, 8104b) the beamforming weights based on acquired primary sector channel state information and secondary sector channel state information of said wireless communication device (111), which central antenna site processing unit (323) supplies (S103C, 8104c) the computed beamforming weights to the primary sector RE device (234a) and the secondary sector RE device (234b).

4. The method of any one of the preceding claims, further comprising: transforming the beamformed data from a frequency domain representation to a time domain presentation before transmitting (S109, S110) the beamformed data to the wireless communication device (111).

5. The method of any one of the preceding claims, further comprising: suppressing (Sio8a), by the secondary sector RE device (234b) interference towards the wireless communication device (111) for which the data transmission is requested (S101) by utilizing the secondary sector beamforming weights, if the secondary sector RE (234b) has data for transmission (Sin) to one or more wireless communication devices (114) on a same frequency as that allocated for the wireless communication device (111) for which the data transmission is requested (S101).

6. The method of claim 1 or claim 5, wherein the receiving (S101) at the primary RE device (234a) and the receiving (S105) at the secondary RE device (234b) is from a radio equipment control, REC, device (320); and when dependent on claim 5, the supressing (sio8a) is instructed by the REC device (320) and the data to be transmitted to said one or more wireless communication devices (114) is received (8105a) from the REC device (320).

7. The method of any one of the preceding claims, the method further comprising: receiving (S201), at the primary sector RE device (234a) from the REC device(320), a request to acquire CSI for said wireless communication device (111); forwarding (S202), from the primary sector RE device (234a), said request to the secondary sector RE device (234b): acquiring (8204a), at the primary sector RE device (234a), channel state information of the wireless communication device (111) to which transmission of data is requested based on Sounding Reference Signal, SRS, measurements performed (8203a) with said wireless communication device (111); and acquiring (8204b), at the secondary sector RE device (234b), channel state information of the wireless communication device (111) to which transmission of data is requested based on SRS measurements performed (8203b) with said wireless communication device (111).

8. The method of claim 7, the respective acquired channel state information being stored (8205a, 8205b) at the primary sector RE device (234a) and the secondary sector RE device (234b).

9. The method of claim 4 and 7, the respective acquired channel state information being stored at the central antenna site processing unit (323).

10. The method of any one of claims 7-9, further comprising: acquiring (S206), at the primary sector RE device (234a), the acquired (8204b) channel state information of the secondary sector RE device (234b); and sending (S207) the acquired (8204a, 8204b) channel state information of the primary sector RE device (234a) and the secondary sector RE device (234b) to the REC device (320).

11. The method of any one of claims 7-9, further comprising: sending the acquired (8204a, 8204b) channel state information of the primary sector RE device (234a) and the secondary sector RE device (234b) from each respective RE device (234a, 234b) to the REC device (320).

12. A computer program (412) comprising computer-executable instructions for causing the primary RE device (234a) to perform steps recited in any one of claims 1-ii when the computer-executable instructions are executed on a processing unit (411) included in primary RE device (234a).

13. A computer program product comprising a computer readable medium (413), the computer readable medium having the computer program (412) according to claim 12 embodied thereon.

14. A computer program (512) comprising computer-executable instructions for causing the secondary RE device (234b) to perform steps recited in any one of claims 1-11 when the computer-executable instructions are executed on a processing unit (511) included in primary RE device (234b).

15. A computer program product comprising a computer readable medium (513), the computer readable medium having the computer program (512) according to claim 14 embodied thereon.

16. Radio equipment, RE, devices (234a, 234b) arranged at an antenna site (300) and configured to cause beamforming towards a primary sector wireless communication device (111) served by the antenna site (300), the RE devices (234a, 234b) each comprising a processing unit (411, 511) and a memory (413, 513), said memory containing instructions (412, 512) executable by said processing unit (411, 511), whereby the RE devices (234a, 234b) are operative to: receive (S101), at a primary sector RE device (234a), a request to transmit data to said wireless communication device (111); forward (S102), from the primary sector RE device (234a), said request to a secondary sector RE device (234b); acquire (8103a, 8103c) primary sector beamforming weights to be applied by the primary sector RE device (234a) for the requested data transmission based on acquired primary sector channel state information of said wireless communication device (111); acquire (8104a, 8104c) secondary sector beamforming weights to be applied by the secondary sector RE device (234b) for the requested data transmission based on acquired secondary sector channel state information of said wireless communication device (111); receive (S105), at the primary sector RE device (234a), data to be transmitted for the requested data transmission to said wireless communication device;forward (S106), by the primary sector RE device (234a) to the secondary sector RE device (234b), the data to be transmitted for the requested data transmission to said wireless communication device (111); apply (S107, S108) the beamforming weights to the data requested to be transmitted by the primary sector RE device (234a) and the secondary sector RE device (234b), wherein the primary sector RE device (234a) applies (S107) the primary sector beamforming weights to the data to be transmitted over a primary sector antenna (301) while the secondary sector RE device (234b) applies (S108) the secondary sector beamforming weights to the data to be transmitted over a secondary sector antenna (302); and to transmit (S109, S110) the beamformed data to the wireless communication device (111) from the primary sector RE device (234a) over the primary sector antenna (301) and from the secondary sector RE device (234b) over the secondary sector antenna (302).

17. The RE devices (234a, 234b) of claim 16, further being operative to, upon acquiring (8103a, 8104a) the beamforming weights computing (8103a) the primary sector beamforming weights the primary sector RE device (234a) and computing (8104a) the secondary sector beamforming weights at the secondary sector RE device (234b).

18. The RE devices (234a, 234b) of claims 16 or 17, further being operative to, upon acquiring (S103C, 8104c) the beamforming weights, acquiring the beamforming weights from a central antenna site processing unit (323) computing (8103b, 8104b) the beamforming weights based on acquired primary sector channel state information and secondary sector channel state information of said wireless communication device (111), which central antenna site processing unit (323) supplies (S103C, 8104c) the computed beamforming weights to the primary sector RE device (234a) and the secondary sector RE device(234b).

19. The RE devices (234a, 234b) of any one of claims 16-18, further being operative to: transform the beamformed data from a frequency domain representation to a time domain presentation before transmitting (S109, S110) the beamformed data to the wireless communication device (111).

20. The RE devices (234a, 234b) of any one of claims 16-19, further being operative to: suppress (Sio8a), by the secondary sector RE device (234b), interference towards the wireless communication device (111) for which the data transmission is requested (S101) by utilizing the secondary sector beamforming weights, if the secondary sector RE (234b) has data for transmission (Sin) to one or more wireless communication devices (114) on a same frequency as that allocated for the wireless communication device (111) for which the data transmission is requested (S101).

21. The RE devices (234a, 234b) of any one of claims 16 or 20, wherein the receiving (S101) at the primary RE device (234a) and the receiving (S105) at the secondary RE device (234b) is from a radio equipment control, REC, device (320); and when dependent on claim 20, the supressing (sio8a) is instructed by the REC device (320) and the data to be transmitted to said one or more wireless communication devices (114) is received (8105a) from the REC device (320).

22. The RE devices (234a, 234b) of any one of claims 16-21, further being operative to: receive (S201), at the primary sector RE device (234a) from the REC device (320), a request to acquire CSI for said wireless communication device (111); forward (S202), from the primary sector RE device (234a), said request to the secondary sector RE device (234b): acquire (8204a), at the primary sector RE device (234a), channel state information of the wireless communication device (111) to which transmission of data is requested based on Sounding Reference Signal, SRS, measurements performed (8203a) with said wireless communication device (111); and acquire (8204b), at the secondary sector RE device (234b), channel state information of the wireless communication device (111) to which transmission of data is requested based on SRS measurements performed (8203b) with said wireless communication device (111).

23. The RE devices (234a, 234b) of claim 22, further being operative to: store (8205a, 8205b) the respective acquired channel state information at the primary sector RE device (234a) and the secondary sector RE device (234b).

24. The RE devices (234a, 234b) of claim 18 and 21, the respective acquired channel state information being stored at the central antenna site processing unit (323).

25. The RE devices (234a, 234b) of any one of claims 22-24, further being operative to: acquire (S206), at the primary sector RE device (234a), the acquired (8204b) channel state information of the secondary sector RE device (234b); and send (S207) the acquired (8204a, 8204b) channel state information of the primary sector RE device (234a) and the secondary sector RE device (234b) to the REC device (320).

26. The RE devices (234a, 234b) of any one of claims 22-24, further being operative to: send the acquired (8204a, 8204b) channel state information of the primary sector RE device (234a) and the secondary sector RE device (234b) from each respective RE device (234a, 234b) to the REC device (320).

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