WO2022171287A1

WO2022171287A1 - Redundancy function for radio network robustness

Info

Publication number: WO2022171287A1
Application number: PCT/EP2021/053359
Authority: WO
Inventors: Rodrigo Alberto JUSTAVINO CASTILLO; Mohammad Hossein JAFARI; Oscar PUNAL
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2021-02-11
Filing date: 2021-02-11
Publication date: 2022-08-18

Abstract

A technique for serving at least one radio device (506) by a first baseband unit (100) of a first network node (150) for compensating a failure of a second baseband unit (200) of a second network node (250) while serving the at least one radio device (506) on radio resources (256) of the second network node (250) is provided. As to a method aspect, a method comprises or initiates a step of monitoring, at the first network node (150), an operation of the second baseband unit (200) of the second network node (250). The method further comprises or initiates a step of serving, by the first baseband unit (100), the at least one radio device (506) on the radio resources (256) of the second network node (250) responsive to determining a failure of the operation of the second baseband unit (200) at the first network node (150).

Description

REDUNDANCY FUNCTION FOR RADIO NETWORK ROBUSTNESS

Technical Field

The present disclosure relates to a technique for compensating a failure of a baseband unit of a network node by a further baseband unit of a further network node in a radio communication network. Alternatively or in addition, the present disclosure relates to a technique for enhancing the reliability of mobile communications and/or to improving the robustness of, in particular a baseband unit of, a radio access network.

Background

Mobile communications, e.g., according to the Long Term Evolution (LTE) or New Radio (NR) radio access technologies of Third Generation Partnership Project (3GPP), enable services, e.g., in the areas of manufacturing, transportation, utilities, and public safety, that require highly reliable communication. The loss of connectivity can have devastating consequences in communication critical scenarios and must be avoided. For this purpose, radio access network (RAN) architectures comprising neighboring network nodes with overlapping coverage areas are conventionally deployed. That is, network nodes and network functions are deployed such that if one fails, a neighboring network node or neighboring network function (either in active or standby state if all neighboring network nodes operate normally, i.e. without failure) can take over the complete traffic and ideally without service interruption.

Once a network node failure has been detected, some action must be taken to avoid losing traffic. In general, the traffic (and/or radio devices, also referred to as user equipments, UEs) must be re-directed to neighboring network nodes, thereby avoiding the failed network node. The sooner a neighboring network node take over the traffic, the less the impact on the service.

Conventionally, radio resources such as bandwidth are shared among neighboring network nodes in a non-overlapping manner, implying a loss of (e.g., half of the spectral) capacity in case a baseband unit of one of the (e.g. of a total of two) neighboring nodes fails. Further, a UE that was served by the failed baseband unit must re-attach to the RAN via a neighboring node, impacting on the overlying services.

Hence, a major problem with conventional techniques is the loss of capacity that results from the failure of a baseband unit of a network node. Such a failure in particular causes a degradation of service for UEs which demand low latency and high reliable connectivity.

Summary

Accordingly, there is a need for a radio communication technique that compensates a failure of a baseband unit without losing overall capacity and/or while minimizing service interruption for one or more radio devices. Alternatively or in addition, there is a need for a technique that enables highly reliable radio network deployments.

As to a first method aspect, a method of serving at least one radio device by a first baseband unit of a first network node for compensating a failure of a second baseband unit of a second network node while serving the at least one radio device on radio resources of the second network node is provided. The method comprises or initiates a step of monitoring, at the first network node, an operation of the second baseband unit of the second network node. The method further comprises or initiates a step of serving, by the first baseband unit, the at least one radio device on the radio resources of the second network node responsive to determining a failure of the operation of the second baseband unit at the first network node.

By the first baseband unit (e.g., the first network node) serving the at least one radio device on the radio resources of the second network node responsive to detecting and/or determining the failure of (e.g., heartbeat signaling of) the second baseband unit of the second network node (which may also be denoted as activating a redundancy function), a loss in capacity (e.g., the capacity provided by the second network node prior to the failure and/or in terms of a spectral and/or temporal capacity of the radio resources of the second network node) can be avoided. Alternatively or in addition, a reliability of a radio access network (RAN) comprising at least the first network node and the second network node can be improved and latency can be mitigated. In a simultaneous operation of the first baseband unit and the second baseband unit and/or prior to the failure of the second baseband unit, each of the first baseband unit (e.g., the first network node) and the second baseband unit (e.g., the second network node) may provide radio access (e.g., simultaneously) using first (e.g., a first share of) radio resources and second (e.g., a second share of) radio resources, respectively. The first radio resources may also be referred to as the radio resources of the first network node. The second radio resources may also be referred to as the radio resources of the second network node. For example, the first network node (e.g., using the first baseband unit) may transmit and/or receive control information and/or data over the first radio resources, and the second network node (e.g., using the second baseband unit) may transmit and/or receive control information and/or data over the second radio resources.

Herein, each of the radio resources of the first network node and the radio resources of the second network node may comprise at least one frequency range (e.g., at least one physical resource block, PRB, or a bandwidth part, BWP) and/or at least one time interval (e.g., at least one subframe, SF, or a configured grant, CG).

The radio resources of the first network node and the radio resources of the second network node may be disjoint and/or non-overlapping.

A RAN may comprise the first network node and the second network node. The RAN (e.g., a network manager node of the RAN and/or an entity of a core network, CN) may allocate the radio resources to the first and second network nodes, respectively (e.g., to the first and second baseband units, respectively). The radio resources of the first network node may be a first share of radio resources of the RAN and the radio resources of the second network node may be a second share of the radio resources of the RAN.

The operation of the second baseband unit may be monitored by the first baseband unit. Alternatively or in addition, the first baseband unit may be triggered to serve the at least one radio device on the radio resources of the second network node responsive to the failure of the second baseband unit. A unit of the first network node, e.g., the first baseband unit or a subunit thereof, which is configured to at least one of monitor the operation of the second baseband unit and serve the at least one radio device responsive to determining the failure may be referred to as a redundancy function. The step of serving the at least one radio device by the first baseband unit on the second radio resources may also be referred to as activating the redundancy function in the first baseband unit of the first network node. Alternatively or in addition, the redundancy function of the first network node for serving the at least one radio device on radio resources of the second network (e.g., for the second radio resources comprising a radio frequency range) may also be denoted as a silent cell and/or a ghost cell.

Prior to the failure of the (e.g., second baseband unit of the) second network node, the first network node and the second network node may serve a first group of radio devices and a second group of radio devices, respectively. The second group of radio devices may comprise the at least one radio device. Each of the first and the second group of radio devices may comprise any number of radio devices served by the first network node and the second network node, respectively. In particular, the first group of radio devices may comprise no radio device and/or the second group of radio devices may comprise the at least one radio device.

Alternatively or in addition, serving the at least one radio device by the first baseband unit (e.g., after the failure of the second baseband unit and/or upon activating the redundancy function in the first baseband unit of the first network node) may comprise the first network node serving both the first group of radio devices and the second group of radio devices on the first radio resources and on the second radio resources, respectively.

The first baseband unit (e.g., the first network node) and the second baseband unit (e.g., the second network node) may comprise mutual redundancy functions to each other. In other words, the second baseband unit may also embody the functions (i.e., may also perform the steps) of the first method aspect.

Alternatively or in addition, the second network node may monitor an operation (e.g., monitor for heartbeat signaling) of the first baseband unit of the first network node. Responsive to detecting a failure of the operation of the first network node by the second baseband unit of the second network node, the second network node may serve one or more radio devices, e.g. the first group of radio devices, on the first radio resources. The first baseband unit or the first network node may refrain from using the radio resources of the second network node prior to the failure. The first baseband unit or the first network node may use the radio resources of the second network node not until the failure of the second network node.

The monitoring of the operation of the second baseband unit may comprise monitoring a heartbeat signaling from the second baseband unit. Alternatively or in addition, the monitoring of the operation of the second baseband unit may comprise monitoring a backhaul communication of the second baseband unit or the second network node. Further alternatively or in addition, the monitoring of the operation of the second baseband unit may comprise monitoring a baseband signal from the second baseband unit. Still further alternatively or in addition, the monitoring of the operation of the second baseband unit may comprise monitoring a radio frequency signal from the second network node. The radio frequency signal may comprise a baseband signal from the second baseband unit.

The method may further comprise or initiate a step of receiving, at the first baseband unit of the first network node from the second baseband unit of the second network node, configuration information as to a configuration of the second baseband unit of the second network node.

The configuration information may be indicative of a status of the second baseband unit. Alternatively or in addition, the configuration information may be indicative of a change or update of the configuration of the second baseband unit.

The configuration information (e.g., sent from the second baseband unit of the second network node and/or received at the first baseband unit of the first network node) may comprise synchronization information, e.g., in relation to the at least one radio device served on the radio resources (e.g., by the second network node). Alternatively or in addition, the configuration information (e.g., transmitted from the second baseband unit of the second network node and/or received at the first baseband unit of the first network node) may comprise information as to a state of the at least one radio device served on the radio resources. The state of the at least one radio device may comprise a radio layer context of the at least one radio device, wherein the radio layer may comprise, e.g., at least one of a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer and/or a radio resource control (RRC) layer.

By receiving configuration information from the second network node, when activating the redundancy function, a re-attachment procedure for the at least one radio device served on the radio resources can be avoided. Alternatively or in addition, by receiving configuration information, reliability of serving the at least one radio device can be improved and latency can be mitigated.

The step of receiving the configuration information may comprise a step of monitoring the operation of the second baseband unit. The failure of the second baseband unit may be determined by the absence of the configuration information.

The step of receiving the configuration information may comprise maintaining a status of the second baseband unit at the first baseband unit. The status of the second baseband unit maintained at the first baseband unit may be updated according to the received configuration information.

The configuration information may be referred to as synchronization information. The configuration information may enable the first baseband unit to maintain the current or up-to-date status of the second baseband unit at the first baseband unit. Maintaining the current or up-to-date status of the second baseband unit at the first baseband unit may also be referred to as synchronizing (i.e., the synchronization of) the status of the second baseband unit at the first baseband unit with the status of the second baseband unit at the second baseband unit.

The received configuration information or the status of the second baseband unit maintained at the first baseband unit may be indicative of a context of the at least one radio device. Alternatively or in addition, the received configuration information or the status of the second baseband unit maintained at the first baseband unit may be indicative of a status of a PDPC layer of the second baseband unit. Further alternatively or in addition, the received configuration information or the status of the second baseband unit maintained at the first baseband unit may be indicative of a status of a RLC layer of the second baseband unit. Still further alternatively or in addition, the received configuration information or the status of the second baseband unit maintained at the first baseband unit may be indicative of a status of a RRC layer of the second baseband unit.

The configuration information may be received periodically. A periodicity of the periodically received configuration information may also be referred to as synchronization period. The step of maintaining the status of the second baseband unit at the first baseband unit (e.g., the synchronization) may comprise receiving the configuration information (e.g., the synchronization information) every subframe. Reducing the synchronization period (e.g. a synchronization period of one subframe) can increase the amount of data that has to be synchronized (i.e., received and/or maintained) in some embodiments and/or may enable an implementation of the technique at (or for) a lower layer of a protocol stack for the serving of (e.g., for a radio communication with) the at least one radio device. Increasing the synchronization period can result in a loss of information on a layer (e.g., on the lowest layer) of a protocol stack for the serving in some embodiments. As an example, synchronization periods longer than 20 ms may result in data loss at the RRC layer of a protocol stack for the serving.

Alternatively or in addition, the transmission and/or reception of the configuration information may be triggered by an event at the second baseband unit.

The configuration information may be received over an interface towards the second baseband unit with a latency and/or a periodicity that is less than one radio frame or less than one subframe of the radio resources.

The interface may be a high-speed interface. The high-speed interface may be an E5 interface, an X2 interface according to the 3GPP standard Long Term Evolution (LTE), and/or an Xn interface according to the 3GPP standard 5G. By way of example, the interface may support a throughput of at least 10 Gbps (i.e.,

10 Gbit/s) with a maximum round trip time of 60 ps (i.e., 60 microseconds).

A content of the received configuration information and/or a content of the status of the second baseband unit maintained at the first baseband unit may depend on a link capacity of a link between the first baseband unit and the second baseband unit on which the configuration information is received. The received configuration information and/or a content of the status of the second baseband unit maintained at the first baseband unit may be indicative of a context of the at least one radio device, if the link capacity is less than a first threshold. The received configuration information and/or a content of the status of the second baseband unit maintained at the first baseband unit may be further indicative of the context of the at least one radio device and a status of a PDPC layer of the second baseband unit, if the link capacity is greater than the first threshold and less than a second threshold. The received configuration information and/or a content of the status of the second baseband unit maintained at the first baseband unit may be further indicative of the context of the at least one radio device, the status of a PDPC layer of the second baseband unit, and a status of an RLC layer of the second baseband unit, if the link capacity is greater than the second threshold.

The received configuration information or the status of the second baseband unit maintained at the first baseband unit may be indicative of at least one of a scheduling of the at least one radio device and a modulation and coding scheme used by the second baseband unit for serving the at least one radio device prior to the failure.

The configuration information (e.g., the synchronizing information) may further be indicative of a status of one or more lower layers (e.g., a medium access control, MAC, layer and/or a physical, PHY, layer) of the second baseband unit, e.g., if the link capacity is greater than a third threshold, which is greater than the second threshold.

The serving may be based on the received configuration information and/or on the status of the second baseband unit maintained at the first baseband unit.

Serving the at least one radio device on the radio resources of the second network node may comprise a step of receiving, at the first network node from a CN, control information and/or data for the at least one radio device served on the radio resources by the second network node. Serving the at least one radio device on the radio resources of the second network node may further comprise a step of transmitting, from the first network node, the received control information and/or data to the at least one radio device on the radio resources. The control information may comprise downlink control information (DCI). Alternatively or in addition, the control information may comprise a scheduling assignment for a downlink (DL) transmission to the at least one radio device and/or a scheduling grant for an uplink (UL) transmission from the at least one radio device.

Serving the at least one radio device may comprise performing DL transmissions to the at least one radio device on the (e.g. second share of) radio resources.

The CN may comprise a 5G core (e.g., comprising an Access and Mobility Function, AMF, and/or a User Plane Function, UPF) according to the 3GPP standard 5G. Alternatively or in addition, the CN may comprise an evolved packet core (EPC, e.g., comprising a Mobility Management Entity, MME, and/or a serving gateway, GW) according to the 3GPP standard LTE.

Alternatively or in addition, serving the at least one radio device on the radio resources of the second network node may comprise a step of receiving, at the first network node from the at least one radio device served on the radio resources by the second network node, control information and/or data. Serving the at least one radio device on the radio resources of the second network node may further comprise a step of sending, from the first network node to a CN, the received control information and/or data.

Serving the at least one radio device may comprise receiving UL transmissions from the at least one radio device on the (e.g., second share of) radio resources.

Any UL transmission may be received on radio resources as granted by the radio network, the UL grant being received from the second network node (e.g., before failure).

The first network node and the second network node may operate in frequency division duplex (FDD) mode and/or time division duplex (TDD) mode.

In simultaneous FDD operation and/or FDD activation mode of both network nodes, the first network node may serve the first group of radio devices on at least one first radio frequency range, and the second network node may serve the second group of radio devices on at least one second radio frequency range. The at least one first radio frequency range and the at least one second radio frequency range may be disjoint and/or non-overlapping. The first network node and the second network node may simultaneously (e.g., within the same subframe) in FDD mode serve the first group of radio devices and the second group of radio devices, respectively.

Alternatively or in addition, in simultaneous TDD operation and/or TDD activation mode of both network nodes, the first network node may serve the first group of radio devices on at least one first time interval, and the second network node may serve the second group of radio devices in at least one second time interval. The at least one first time interval and the at least one second time interval may be disjoint and/or non-overlapping. For example, the at least one first time interval may comprise odd numbered subframes, and the at least one second time interval may comprise even numbered subframes, or vice versa. The first network node and the second network node may in TDD mode serve the first group of radio devices and the second group of radio devices, respectively, alternatingly in time using the same radio frequency range.

The radio resources may comprise frequency resources. Alternatively or in addition, the radio resources may comprise time resources.

For example, the first and second radio resources may use the same carrier frequency or radio frequency band, wherein subcarriers, PRBs or BWPs used by the first and second baseband units are disjoint and/or non-overlapping.

The radio resources used by the first baseband unit for serving a first group of radio devices prior to the failure of the second baseband unit and the radio resources of the second baseband unit used by the first baseband unit for serving a second group of radio devices including the at least one radio device after the failure may be equal in capacity.

The first network node may serve a first group of radio devices on a first share of radio resources and the second network node may serve a second group of radio devices comprising the at least one radio device on a second share of radio resources prior to the failure. The first share and the second share may have equal capacity. The capacity may comprise a spectral capacity, e.g., a radio frequency range. Alternatively or in addition, the capacity may comprise a temporal capacity, e.g., a number of (in particular consecutive) frames, subframes, transmission time intervals (TTIs) and/or short TTIs (sTTIs).

The first share of radio resources and the second share of radio resources may be arranged in a comb-like structure in time and/or in frequency.

The method may further comprise a step of sending heartbeat signaling from the first baseband unit of the first network node to the second network node.

Alternatively or in addition, the method may further comprise a step of sending configuration information as to a configuration of the first baseband unit of the first network node from the first baseband unit of the first network node to the second baseband unit of the second network node.

As to a second method aspect, a method of preparing a first baseband unit of a first network node to serve at least one radio device for compensating a failure of a second baseband unit of a second network node while serving the at least one radio device on radio resources of the second network node is provided. The method comprises or initiates a step of sending heartbeat signaling from the second baseband unit of the second network node to the first network node. The method further comprises or initiates a step of sending configuration information as to a configuration of the second baseband unit of the second network node from the second baseband unit of the second network node to the first baseband unit of the first network node.

The method of the second method aspect may further comprise or initiate any step, and/or comprise any feature, according to or corresponding to any one of the steps and/or features disclosed in the context of the first method aspect.

Without limitation, for example in a 3GPP implementation, any "radio device" may be a user equipment (UE), e.g., according to a 3GPP specification.

The technique may be applied in the context of 3GPP New Radio (NR) and/or 3GPP Long Term Evolution (LTE). The RAN may comprise one or more base stations, e.g., performing the first and second method aspects.

Any one of the radio devices may be a 3GPP user equipment (UE) or a Wi-Fi station (STA). The radio device may be a mobile or portable station, a device for machine- type communication (MTC), a device for narrowband Internet of Things (NB-loT) or a combination thereof. Examples for the UE and the mobile station include a mobile phone, a tablet computer and a self-driving vehicle. Examples for the portable station include a laptop computer and a television set. Examples for the MTC device or the NB-loT device include robots, sensors and/or actuators, e.g., in manufacturing, automotive communication and home automation. The MTC device or the NB-loT device may be implemented in a manufacturing plant, household appliances and consumer electronics.

Whenever referring to the RAN, the RAN may be implemented by one or more base stations.

The base station may encompass any station that is configured to provide radio access to any of the radio devices. The base stations may also be referred to as network node, cell, transmission and reception point (TRP), radio access node or access point (AP). The base station may provide a data link to a host computer providing the user data to the remote radio device or gathering user data from the remote radio device. Examples for the base stations may include a 3G base station or Node B, 4G base station or eNodeB, a 5G base station or gNodeB, a Wi-Fi AP and a network controller (e.g., according to Bluetooth, ZigBee or Z-Wave).

The RAN may be implemented according to the Global System for Mobile Communications (GSM), the Universal Mobile Telecommunications System (UMTS), 3GPP Long Term Evolution (LTE) and/or 3GPP New Radio (NR).

Any aspect of the technique may be implemented on a Physical Layer (PHY), a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, a packet data convergence protocol (PDCP) layer, and/or a Radio Resource Control (RRC) layer of a protocol stack for the radio communication.

As to another aspect, a computer program product is provided. The computer program product comprises program code portions for performing any one of the steps of the method aspects disclosed herein when the computer program product is executed by one or more computing devices. The computer program product may be stored on a computer-readable recording medium. The computer program product may also be provided for download, e.g., via the radio network, the RAN, the Internet and/or the host computer. Alternatively, or in addition, the method may be encoded in a Field-Programmable Gate Array (FPGA) and/or an Application-Specific Integrated Circuit (ASIC), or the functionality may be provided for download by means of a hardware description language.

As to a first device aspect, a first baseband unit for serving at least one radio device by the first baseband unit of a first network node for compensating a failure of a second baseband unit of a second network node while serving the at least one radio device on radio resources of the second network node is provided. The device may be configured to perform any one of the steps of the first method aspect. Alternatively or in addition, the first baseband unit is configured to monitor, at the first network node, an operation of the second baseband unit of the second network node. The first baseband unit is further configured to serve the at least one radio device on the radio resources of the second network node responsive to determining a failure of the operation of the second baseband unit at the first network node.

As to a further first device aspect, a first baseband unit for serving at least one radio device by the first baseband unit of a first network node for compensating a failure of a second baseband unit of a second network node while serving the at least one radio device on radio resources of the second network node is provided. The device comprises processing circuitry (e.g., at least one processor and a memory). Said memory comprises instructions executable by said at least one processor whereby the device is operative to perform any one of the steps of the first method aspect.

As to a second device aspect, a second baseband unit for preparing a first baseband unit of a first network node to serve at least one radio device for compensating a failure of the second baseband unit of a second network node while serving the at least one radio device on radio resources of the second network node is provided. The device may be configured to perform any one of the steps of the second method aspect. Alternatively or in addition, the second baseband unit is configured to send heartbeat signaling from the second baseband unit of the second network node to the first network node. The second baseband unit is further configured to send configuration information as to a configuration of the second baseband unit of the second network node to the first baseband unit of the first network node.

As to a further second device aspect, a second baseband unit for preparing a first baseband unit of a first network node to serve at least one radio device for compensating a failure of the second baseband unit of a second network node while serving the at least one radio device on radio resources of the second network node is provided. The device comprises processing circuitry (e.g., at least one processor and a memory). Said memory comprises instructions executable by said at least one processor whereby the device is operative to perform any one of the steps of the second method aspect.

As to a further aspect, a first network node for serving at least one radio device by a first baseband unit of the first network node for compensating a failure of a second baseband unit of a second network node while serving the at least one radio device on radio resources of the second network node is provided. The first network node may be configured to perform any one of the steps of the first method aspect.

As to a still further aspect, a second network node for preparing a first baseband unit of a first network node to serve at least one radio device for compensating a failure of a second baseband unit of the second network node while serving the at least one radio device on radio resources of the second network node is provided. The second network node may be configured to perform any one of the steps of the second method aspect.

As to a still further aspect, a communication system including a host computer is provided. The host computer comprises a processing circuitry configured to provide user data. The host computer further comprises a communication interface configured to forward the first and/or second data to a radio (also: "cellular") network (e.g., the RAN, the first network node and/or the second network node) for transmission to a UE. The radio network comprises a first network node and a second network node. The first network node and the second network node are configured to communicate with the UE. The first network node comprises a radio interface and processing circuitry configured to execute any one of the steps of the first method aspect. Alternatively or in addition, the second network node comprises a radio interface and processing circuitry configured to execute the any one of the steps of the second method aspect.

The communication system may further include the UE. The UE may comprise a radio interface and processing circuitry.

The processing circuitry of the host computer may be configured to execute a host application, thereby providing the first and/or second data and/or any host computer functionality described herein. Alternatively, or in addition, the processing circuitry of the UE may be configured to execute a client application associated with the host application.

Any one of the devices, the UE, the base station, the communication system or any node or station for embodying the technique may further include any feature disclosed in the context of the method aspects, and vice versa. Particularly, any one of the units and modules disclosed herein may be configured to perform or initiate one or more of the steps of the first method aspect and/or the second method aspect.

Brief Description of the Drawings

Further details of embodiments of the technique are described with reference to the enclosed drawings, wherein:

Fig. 1 shows a schematic block diagram of an embodiment of a first baseband unit of a first network node for serving one or more radio devices by a first baseband unit for compensating a failure of a second baseband unit of a second network node while serving the one or more radio devices on radio resources of the second network node;

Fig. 2 shows a schematic block diagram of a second baseband unit of a second network node for preparing a first baseband unit of a first network node to serve one or more radio devices for compensating a failure of the second baseband unit while serving the one or more radio devices on radio resources of the second network node; Fig. 3 shows a flowchart for a method of serving one or more radio devices by a first baseband unit of a first network node for compensating a failure of a second baseband unit of a second network node while serving the one or more radio devices on radio resources of the second network node, which method may be implementable by the first baseband unit of Fig. 1;

Fig. 4 shows a flowchart for a method of preparing a first baseband unit of a first network node to serve one or more radio devices for compensating a failure of a second baseband unit of a second network node while serving the one or more radio devices on radio resources of the second network node, which method may be implementable by the second baseband unit of Fig. 2;

Fig. 5 shows a first embodiment of a deployment of two network nodes with corresponding baseband units operating on two different shares of radio resources;

Fig. 6 shows a second embodiment of a deployment of two network nodes with corresponding baseband units operating on two different shares of radio resources, wherein each baseband unit is connected to the radio interfaces of both network nodes, such that both nodes simultaneously operate on both shares of radio resources;

Figs. 7A and 7B schematically illustrate an example impact of a failure of a second baseband unit for the first embodiment of a deployment of two network nodes of Fig. 5, wherein the different shares of radio resources comprise non-overlapping frequency ranges;

Fig. 8A and 8B show a first embodiment of a deployment of a first baseband unit of a first network node for compensating a failure of a second baseband unit of a second network node by serving a radio device on a second share of radio resources of the second network node, with a first share and the second share of radio resources comprising different non-overlapping frequency ranges for the first and second network node, respectively, which first baseband unit and second baseband unit may be implementable by those of Figs. 1 and 2, respectively; Fig. 9A and 9B show a second embodiment of a deployment of a first baseband unit of a first network node for compensating a failure of a second baseband unit of a second network node by serving a radio device on a second share of radio resources of the second network node, with a first share and the second share of radio resources comprising different non overlapping time intervals for the first and second network node, respectively, which first baseband unit and second baseband unit may be implementable by those of Figs. 1 and 2, respectively;

Fig. 10 shows a schematic block diagram of a first network node embodying the device of Fig. 1;

Fig. 11 shows a schematic block diagram of a second network node embodying the device of Fig. 2;

Fig. 12 schematically illustrates an example telecommunication network connected via an intermediate network to a host computer;

Fig. 13 shows a generalized block diagram of a host computer communicating via a base station or radio device functioning as a gateway with a user equipment over a partially wireless connection; and

Figs. 14 and 15 show flowcharts for methods implemented in a communication system including a host computer, a base station or radio device functioning as a gateway and a user equipment.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as a specific network environment in order to provide a thorough understanding of the technique disclosed herein. It will be apparent to one skilled in the art that the technique may be practiced in other embodiments that depart from these specific details. Moreover, while the following embodiments are primarily described for a New Radio (NR) or 5G implementation, it is readily apparent that the technique described herein may also be implemented for any other radio communication technique, including a Wireless Local Area Network (WLAN) implementation according to the standard family IEEE 802.11, 3GPP LTE (e.g., LTE-Advanced or a related radio access technique such as MulteFire), for Bluetooth according to the Bluetooth Special Interest Group (SIG), particularly Bluetooth Low Energy, Bluetooth Mesh Networking and Bluetooth broadcasting, for Z-Wave according to the Z-Wave Alliance or for ZigBee based on IEEE 802.15.4.

Moreover, those skilled in the art will appreciate that the functions, steps, units and modules explained herein may be implemented using software functioning in conjunction with a programmed microprocessor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Digital Signal Processor (DSP) or a general purpose computer, e.g., including an Advanced RISC Machine (ARM). It will also be appreciated that, while the following embodiments are primarily described in context with methods and devices, the invention may also be embodied in a computer program product as well as in a system comprising at least one computer processor and memory coupled to the at least one processor, wherein the memory is encoded with one or more programs that may perform the functions and steps or implement the units and modules disclosed herein.

Fig. 1 schematically illustrates a block diagram of an embodiment of a first baseband unit of a first network node. The first baseband unit is generically referred to by reference sign 100.

The first baseband unit 100 comprises a second baseband unit monitoring module 102 that is configured to monitor, at the first network node, an operation of a second baseband unit of a second network node. The first baseband unit 100 further comprises a radio device serving module 106 that is configured to serve one or more radio devices on radio resources of the second network node responsive to determining a failure of the operation of the second baseband unit at the first network node.

Optionally, the first baseband unit 100 comprises a configuration information receiving module 104 that is configured to receive, from the second baseband unit of the second network node, configuration information as to a configuration of the second baseband unit of the second network node.

Any of the modules of the baseband unit 100 may be implemented by (e.g. sub-) units configured to provide the corresponding functionality. The baseband unit 100 may also be referred to as, or may be embodied by, the first network node. The first network node 100 and the second network node may be in direct radio communication and/or direct wired communication, e.g., at least for the monitoring of the second baseband unit. The second network node may be embodied by the second baseband unit 200.

Fig. 2 schematically illustrates a block diagram of an embodiment of a second baseband unit of a second network node. The second baseband unit is generically referred to by reference sign 200.

The second baseband unit 200 comprises a heartbeat signaling module 202 that is configured to send heartbeat signaling from the second baseband unit of the second network node to a first network node. The second baseband unit 200 further comprises a configuration information sending module that is configured to send configuration information as to a configuration of the second baseband unit 200 to a first baseband unit of the first network node.

Any of the modules of the baseband unit 200 may be implemented by (e.g. sub-) units configured to provide the corresponding functionality.

The baseband unit 200 may also be referred to as, or may be embodied by, the second network node. The first network node and the second network node 200 may be in direct radio communication and/or direct wired communication, e.g., at least for sending the heartbeat signaling and/or configuration information. The first network node may be embodied by the first baseband unit 100.

Fig. 3 shows an example flowchart for a method 300 of serving one or more radio devices by a first baseband unit of a first network node for compensating a failure of a second baseband unit of a second network node while serving the one or more radio devices on radio resources of the second network node.

In a step 302, an operation of the second baseband unit of the second network node is monitored at the first network node. In a step 306, the one or more radio devices are served, responsive to determining a failure of the operation of the second baseband unit at the first network node, by the first baseband unit on the radio resources of the second network node. Optionally, in a step 304, configuration information as to a configuration of the second baseband unit of the second network node is received at the first baseband unit of the first network node from the second baseband unit of the second network node.

The method 300 may be performed by the first baseband unit 100. For example, the modules 102, 104 and 106 may perform the steps 302, 304 and 306, respectively.

Fig. 4 shows an example flowchart for a method 400 of preparing a first baseband unit of a first network node to serve one or more radio device for compensating a failure of a second baseband unit of a second network node while serving the one or more radio devices on radio resources of the second network node.

In a step 402, heartbeat signaling is sent from the second baseband unit of the second network node to the first network node. In a step 404, configuration information as to a configuration of the second baseband unit of the second network node is sent from the second baseband unit of the second network node to the first baseband unit of the first network node.

The method 400 may be performed by the second baseband unit 200. For example, the modules 202 and 204 may perform the steps 402 and 404, respectively.

Each of the first baseband unit 100 and second baseband unit 200 may be network node and/or a base station in radio communication with one or more radio devices. Herein, any radio device may be a mobile or portable station and/or any radio device wirelessly connectable to a base station or RAN, or to another radio device. For example, the radio device may be a user equipment (UE), a device for machine-type communication (MTC) or a device for (e.g., narrowband) Internet of Things (loT). Two or more radio devices may be configured to wirelessly connect to each other, e.g., in an ad hoc radio network or via a 3GPP SL connection. Furthermore, any base station may be a station providing radio access, may be part of a radio access network (RAN) and/or may be a node connected to the RAN for controlling the radio access. For example, the base station may be an access point, for example a Wi-Fi access point. Once a failure of a baseband unit failure and/or of a network node has been detected, e.g., a failure of the second baseband unit 200, some action must be taken to avoid losing traffic. The traffic and/or the radio devices (and/or users) must be directed to one or more further network nodes (and/or their respective baseband units), thereby avoiding the failed network node. The sooner the one or more further network nodes take over the traffic, the less the impact on the service.

By the method 300 and/or 400, energy may be saved at the RAN 502, e.g. the first network node 100 and/or the second network node 200, and/or at one or more radio devices served by the RAN 502, e.g., a radio device served by the second network node 200.

One example of a network setup 500 comprising two network nodes is illustrated in Fig. 5.

A core network (CN) 504 comprises in the embodiment of Fig. 5 two evolved packet cores (EPCs) denoted as EPC 1 and EPC 2 serving a radio access network (RAN) 502 comprising a first network node 510 and a second network node 520. Each network node comprises a remote radio unit (RRU) at reference sign 512 and 522 for the first and second network node 510 and 520, respectively, each coupled to an antenna or an antenna array of the respective network node 510 and/or 520. The first network node 510 comprises a first baseband unit 530 serving a first cell 532 on a first share of radio resources 534, e.g., in a first frequency range. The second network node comprises a second baseband unit 540 serving a second cell 542 on a second share of radio resources 544, e.g., in a second frequency range. A coverage area of the first cell 532 and the second cell 542 may be overlapping. The first share of radio resources 534 and the second share of radio resources 544 may be disjoint and/or non-overlapping.

An alternative deployment of two network nodes 510 and 520 is displayed in Fig.

6. In the embodiment of Fig. 6, the first baseband unit 530 of the first network node 510 is, in addition to the communication with the first RRU 512, in communication with the second RRU 522 of the second network node 520. The second baseband unit 540 of the second network node 520 is, in addition to the communication with the second RRU 522, in communication with the first RRU 512. Both network nodes 510 and 520 serve their respective cells 532 and 542 on both the first and second shares of radio resources 534 and 544, e.g., first and second frequency ranges, associated with the first baseband unit 530 and the second baseband unit 540, respectively. The coverage area of the first cell 532 and the coverage area of the second cell 542 may be overlapping, leading to interference (e.g., interference patterns) of the simultaneous transmission of data and/or control information associated to one baseband unit, e.g., the first baseband unit 530, on the first share of radio resources 534, e.g., the first frequency range, in both cells 532 and 542.

Although both deployments in Figs. 5 and 6 comprise two baseband units 530 and 540 at two network nodes 510 and 520, respectively, in each of these deployments, a failure of one of the baseband units 530 or 540 implies a loss of half of the (e.g., spectral and/or temporal) capacity. In other words, while such existing systems may provide redundancy for the CN 504, the RRUs 512 and 522, and antennas, there is no redundancy for the baseband unit.

Furthermore, the baseband units 530 and 540 are uniquely associated with their respective basebands so that the same capacity loss occurs in case of a failure of a baseband unit 530 or 540 in each of the existing systems of Figs. 5 and 6.

An illustrative example is provided in Figs. 7A and 7B. The deployment in Fig. 7A corresponds to the deployment of Fig. 5 with the shares of radio resources split into frequency ranges fl at reference sign 534 and f2 at reference sign 544 for the first baseband unit 530 and the second baseband unit 540, respectively. The first baseband unit 530 of the first network node 510 serves the first cell 532 on the first frequency range fl at reference sign 534. The second baseband unit 540 of the second network node 540 serves the second cell 542 on the second frequency range at reference sign 544 in Fig. 7A. The two cells 532 and 542 may also be denoted as radio cells and/or "legs" of the RAN.

As shown in Fig. 7A, the (e.g., total amount of available) bandwidth (as an example of radio resources 534, 544) is split equally among both cells 532 and 542. The carrier frequencies fl and f2 at reference signs 534 and 544, respectively, of the cells 532 and 542, respectively, are disjoint and/or do not overlap. As shown in Fig. 7B, in case of a failure of a baseband unit (e.g., the second baseband unit 540) a complete "leg" is affected. As a result, only a single cell is available, e.g. the first cell 532 in Fig. 7B. Users and/or radio devices that were served by the second cell 542 (e.g., in Fig. 7A) must conventionally re-attach to the RAN 502 via the first cell 532 (e.g., in Fig 7B). Besides the impact on the overlying services, the overall capacity of the RAN 502 is halved, as only the radio resources 534 and/or bandwidth of the first cell 532 carrier is available.

Hence, conventionally a loss of (e.g., spectral and/or temporal) capacity results from the failure of a baseband unit, e.g. the second baseband unit 540. A failure of the baseband unit (e.g., the second baseband unit 540) conventionally causes a degradation of service for radio devices which demand for low latency and high reliable connectivity.

The problems of capacity loss and degradation of service of conventional deployments of two network nodes 510 and 520 comprising each a baseband unit 530, 540 may be overcome as follows. A technique for detecting and/or determining the failure of a baseband unit, e.g. the second baseband unit 200, may be provided. Alternatively or in addition, a technique for serving, by the first network node, one or more radio devices on radio resources of second network node is provided (which may also be denoted as implementing a redundancy function for the second baseband unit in the first baseband unit). By detecting and/or determining the failure of a baseband unit and activating the corresponding redundancy function, a loss of the overall (e.g., spectral and/or temporal) capacity of the RAN may be avoided and service interruption (e.g., for one or more radio devices) may be minimized.

For detecting and/or determining a failure of one of the baseband units 100 or 200, a heartbeat signaling between the first baseband unit 100 of the first network node and the second baseband unit 200 of the second network node may be introduced. Alternatively or in addition, the first baseband unit 100 may monitor the operation of the second baseband unit 200 by monitoring a backhaul communication and/or a baseband signal from the second baseband unit 200, or vice versa.

As a reaction to detecting and/or determining a failure of a baseband unit (e.g., of the second baseband unit 200 at the second network node), and to avoid overall (e.g., spectral and/or temporal) capacity losses, the method 300 is performed by the baseband unit of the other network node (e.g., the first baseband unit 100 of the first network node). Alternatively or in addition, each network node (e.g., the second baseband unit 200 of the second network node) may perform the method 400 to prepare the other network node (e.g., the first baseband unit 100 of the first network node) for performing the method 300.

A first embodiment of the methods 300 and/or 400 is based on the existence of a "silent" cell (also denoted as "ghost" cell) for each active cell. Alternatively or in addition, the first embodiment of the methods 300 and/or 400 is based on frequency division duplex (FDD) and/or on a splitting of radio resources in terms of frequency ranges fl and f2.

A second embodiment of the methods 300 and/or 400, which may be combined with the first embodiment of the methods 300 and/or 400, is based on the concept of time division duplex (TDD) and/or on a splitting of radio resources in terms of time intervals.

In any embodiment, the methods 300 and/or 400 enable highly reliable network (e.g., RAN) deployments that do not suffer from (e.g., spectral and/or temporal) capacity losses in case of a failure of a baseband unit (e.g., the second baseband unit 200). High reliability may be especially important in dedicated and mission critical networks (e.g., RANs).

Embodiments of the methods 300 and/or 400 may be based on standard- compliant techniques, e.g., according to the NR and/or LTE 3GPP standards, that do not require changes to the radio devices and/or network nodes.

Hereinafter, the technique is illustrated by a number of exemplary embodiments. These embodiments are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present in another embodiment, and a person skilled in the art will readily appreciate combinations of those components used for further exemplary embodiments.

Embodiments of the technique can use at least one of two embodiments of the methods 300 and/or 400 to recover from a failure of a baseband unit (e.g., the second baseband unit 200) without loss of (e.g., spectral and/or temporal) capacity. The technique is designed to minimize service interruption and/or radio capacity optimization whilst keeping reliability of connectivity with redundant systems (e.g., comprising first and second baseband units 100 and 200, respectively, and/or a first and second network node).

Upon detection and/or determination of a failure of a baseband unit (e.g., the second baseband unit 200), the network (e.g., RAN) system needs to swiftly react and recover itself from the capacity loss and the service loss.

A first embodiment of a first baseband unit 100 and a second baseband unit 200 performing the methods 300 and 400, respectively, is shown in Figs. 8A and 8B. In the first embodiment, a "silent" cell is deployed for each active cell. Alternatively or in addition, in the first embodiment, two network nodes operate in FDD mode.

According to any embodiment, the first and second baseband units 100 and 200 of the first and second network node 150 and 250, respectively, are configured to perform the method 300 and the method 400, respectively, e.g., being implemented as a redundancy function.

According to the first embodiment of the methods 300 and/or 400, in the first baseband unit 100 of the network node 150, the redundancy function configures a "silent" cell (also denoted as "ghost" cell, e.g., cell 1-2 at reference sign 160 at the first network node 150) with the same parameters as the active cell (e.g., cell 2-1 at reference sign 258) of the second (e.g., neighbor) baseband unit 200 of the second network node 250 (and vice versa). The redundancy function keeps the "silent" cell (e.g., cell 1-2 at reference sign 160 of the first network node 150 and/or cell 2-2 at reference sing 260 of the second network node 250 in Fig. 8A) locked if the corresponding (e.g., neighbor) baseband unit is active and/or in operation. Alternatively or in addition, in the active baseband unit (e.g., the second baseband unit 200 in Fig. 8A), the methods 300 and 400, e.g., implemented as the redundancy function using a (e.g., high-speed) interface, keep the "silent" cell (e.g., the cell 1-2 at reference sign 160) in the other baseband unit (e.g., the first baseband unit 100) constantly updated with the latest scheduling information. In this way, the "silent" cell (e.g., the cell 1-2 at reference sign 160) becomes a copy of the active cell (e.g., the cell 2-1 at reference sign 258).

If the baseband unit (e.g., the second baseband unit 200) hosting the active cell (e.g., the cell 2-1 at reference sign 258) fails as shown in Fig. 8B, the failure is detected and/or determined, e.g., by the heartbeat system or any other detection system in place, and the redundancy function in the other baseband unit (e.g., the first baseband unit 100) commands it to unlock its "silent" cell (e.g., the cell 1-2 at reference sign 160). A re-attach of a radio device 506 to the RAN 502 may not be necessary as the "silent" cell (e.g., the cell 1-2 at reference sign 160) has the exact same configuration and information as the active one which failed (e.g., the cell 2- 1 at reference sign 258). Some (e.g., minor) data loss may occur depending on the time of the last update (e.g., between the first baseband unit 100 and the second baseband unit 200 using the corresponding interfaces 154 and 254, e.g. comprising an X2-interface according to LTE and/or an Xn-interface according to NR). The (e.g., minor) data loss may result in a limited service impact without capacity loss.

In the embodiment of Fig. 8A, cell 1-2 at reference sign 160 and cell 2-2 at reference sign 260 are the "silent" cells configured in the first baseband unit 100 and the second baseband unit 200, respectively, with the same parameters as the active cells 258 and 158, respectively, of the other network node. Cell 1-2 at reference sign 160 has the same configurations as cell 2-1 at reference sign 258. Cell 2-2 at reference sign 260 has the same configurations as cell 1-1 at reference sign 158.

Each of the baseband units 100 and 200 may be uniquely associated with one antenna (e.g., one antenna system at one location). Alternatively or in addition, the baseband units 100 and 200 may be associated with their basebands 156 and 256, respectively, and, by virtue of the redundancy function, with each other's basebands 256 and 156, respectively, although the other's baseband is not used in case of normal operation (e.g., prior to the failure), as is illustrated by the dashed lines of the unused spectral resources in Fig. 8A.

As shown in Fig. 8A, during normal network (e.g., RAN 502) operation, both "silent" cells 1-2 and 2-2 at reference signs 160 and 260, respectively, are inactive. The first network node 150 may serve a first group of radio devices 506 using a first frequency range 156 of the active cell 1-1 at reference sign 158. The first group of radio devices 506 may be served by the first network node 150 through the radio interface 152 comprising a RRU and at least one antenna or at least one antenna array. The second network node 250 may serve a second group of radio devices 506 using a second frequency range 256, which is disjoint and/or non overlapping from the first frequency range 156 of the active cell 2-1 at reference sign 258. The second group of radio devices 506 may be served by the second network node 250 through the radio interface 252 comprising a RRU and at least one antenna or at least one antenna array.

As shown in Figs. 8A and 8B, the RAN 502 comprising the first network node 150 and the second network node 250 of the first embodiment may be connected to a CN 504, e.g., comprising one or more EPCs according to the 3GGP standard LTE and/or one or more 5G cores (5GCs) according to the 3GPP standard NR. While the baseband unit 100 is prepared to use the spectrum of its "silent" cell, which spectrum is illustrated by dashed lines in Fig. 8A in case of normal operation, only cells 1-1 and 2-1 at reference signs 158 and 258, respectively, are in operation and therefore the spectrum of the silent cells 1-2 and 2-2 at reference signs 160 and 260, respectively, is not used (as indicated by using no solid lines). That is, in the case of the box showing the frequency utilization of Antenna 1, only the blocks 1 to 4 at reference sign 156 are marked as being used.

In case one of the baseband units 100 or 200 gets out of operation (e.g., the second baseband unit 200 in Fig. 8B), the redundancy function on the other baseband unit (e.g., the first baseband unit 100 in Fig. 8B) activates its "silent" cell (e.g., the cell 1-2 at reference sign 160) to avoid service interruption and capacity loss, e.g. for a group of radio devices 506 served by the second network node 250. The other baseband unit (e.g., the first baseband unit 100) serves the first group of radio devices 506 using the first frequency range 156 and serves the second group of radio devices 506 using the second frequency range 256 after activation of the redundancy function. In other words, after the baseband unit 200 fails in Fig. 8B, cell 1-2 is activated and the frequency use by the first baseband unit 100 (i.e., at the Antenna 1) comprises (cf. the 8 marked boxes) both frequency resources 156 and 256.

A second embodiment of a first baseband unit 100 and a second baseband unit 200 performing the method 300 and 400, respectively, (which may also be denoted as activating the redundancy function and/or recovery of a failure of a baseband unit), which is combinable with the first embodiment, is shown in Figs. 9A and 9B. In the second embodiment, two network nodes 150 and 250 operate in TDD mode. Like units, entities and/or functions as in the first embodiment of Figs. 8A and 8B are furnished with identical reference signs in Figs. 9A and 9B. The second embodiment of Figs. 9A and 9B is suitable for "lean" wireless communication systems such as NR, in which reference signals (RSs) are sent only during user data transmissions and almost no RSs are transmitted while the cell is idle. In the second embodiment shown in Fig. 9A, a TDD-like operation mode comprising TDD-like transmissions and/or TDD-like receptions of a first network node 150 and of a second network node 250 in a RAN 502 are employed. The TDD- like transmissions and/or TDD-like receptions of each baseband unit 100 and 200 and/or each cell 158 and 258 may use the same frequency carrier, but are disjoint in time and/or do not overlap in time. E.g., during a time 156 (or a time 256), the baseband unit 200 (or the baseband unit 100) and/or the cell 258 (or the cell 158) remains silent. The network node 200 will avoid transmissions and/or receptions during the time 156. Alternatively or in addition, the network node 100 will avoid transmissions and/or receptions during the time 256. The two baseband units 100 and 200 are coordinated by means of the methods 300 and 400, e.g. implemented as a redundancy function placed in both baseband units 100 and 200.

In the second embodiment, the first baseband unit 100 and the second baseband unit 200 may be connected via a (e.g., high-speed) interface (e.g., an Xn-interface according to NR) at reference signs 154 and 254.

As shown in Fig. 9B, the method 300 and/or 400 allows the network node 150 (e.g., a gNodeB or briefly "gNB" according to NR) to adjust the empty subframe pattern if necessary, e.g. according to traffic demands. In case of a failure of a baseband unit (e.g., the second baseband unit 200), the failure is detected and/or determined by the heartbeat system or any other detection system in place (e.g., using the interface 154, 254). The detection and/or determination of the failure triggers the redundancy function in the remaining baseband unit (e.g., the baseband unit 100) to instruct the network node 150 (e.g., a gNB) to stop transmitting empty subframes and use the entire frame capacity, e.g. comprising time intervals 156 and time intervals 256. Users and/or radio devices 506 (e.g., previously served by the second network node 250 and/or cell 2 at reference sign 258) have to re-attach to the network via the remaining cell 1 at reference sign 158. The re-attachment results in limited service impact, but no capacity loss.

Figs. 9A and 9B show an embodiment of the methods 300 and 400 using the TDD scheme for two baseband units (e.g., first baseband unit 100 and second baseband unit 200). In Fig. 9A, the first baseband unit 100 transmits on cell 1 at reference sign 158, and the second baseband unit 200 transmits on cell 2 at reference sign 258. Both cells 158 and 258 use the entire available (e.g., frequency) spectrum and cover (e.g., at least partially) the same area. Interference is avoided by applying TDD between both cells 158 and 258, namely while cell 1 at reference sign 158 transmits (e.g., in time intervals 156), cell 2 at reference sign 258 remains silent and vice versa. Both cells 158 and 258 agree on which subframes 156 and 256, respectively, to transmit.

As shown in Figs. 9A and 9B, the RAN 502 comprising the first network node 150 and the second network node 250 of the second embodiment may be connected to a CN 504, e.g., comprising one or more 5GCs according to the 3GPP standard NR.

In Fig. 9B, the second baseband unit 200 fails, which means that the cell 2 at reference sign 258 goes out of service. Once the cell 1 at reference sign 158 is notified, it stops transmitting almost blank subframes (e.g., at reference sign 256). Then users and/or radio devices 506 that were connected to cell 2 at reference sign 258 may attempt to connect to cell 1 at reference sign 158.

In any embodiment, by the interface 154 and 254, data and/or parameters may be exchanged between the first baseband unit 100 and the second baseband unit 200 for synchronization.

As part of the synchronization, information about the active cell may periodically updated in the "silent" cell (also denoted as "ghost" cell). The information may include information about at least one of a radio device context (e.g., a UE context and/or one or more radio device 506 contexts in Figs. 8A and 8B and/or Figs. 9A and 9B), a PDPC layer status (e.g., at the respective network node 150, 250 and/or at the radio device 560), or an RLC layer status (e.g., at the respective network node 150, 250 and/or at the radio device 560).

Depending on the capacity of the link between the two baseband units (e.g., the first baseband unit 100 and the second baseband unit 200), the information exchanged may synchronize only one or a subset of the radio device (e.g., UE) context information (option 1), the radio device (e.g., UE) context information and the PDCP layer information (option 2) and/or the radio device (e.g., UE) context information, the PDCP and RLC layers information (option 3). Option 1 requires less capacity in the link between the two baseband units (e.g., baseband units 100 and 200) at the expense of more data loss and a longer reconnection time for the radio device (e.g., UE) after a failure of a baseband unit (e.g., the second baseband unit 200). Alternatively or in addition, option 3 decreases the data loss and the reconnection time at the expense of requiring more information to be synchronized in the link between the two baseband units (e.g., the first baseband unit 100 and the second baseband unit 200).

Alternatively or in addition, synchronizing information at lower layers (e.g., MAC and PHY) can further minimize the loss of data and the time required for a radio device (e.g., UE) to switch to the remaining baseband unit (e.g., using the "silent" cell 160). In some embodiments, the required periodicity and amount of data of the updates may not be supported by the interface 154, 254 connecting the two baseband units 100, 200.

Fig. 10 shows a schematic block diagram for an embodiment of the first baseband unit 100. The first baseband unit 100 comprises processing circuitry, e.g., one or more processors 1004 for performing the method 300 and memory 1006 coupled to the processors 1004. For example, the memory 1006 may be encoded with instructions that implement at least one of the modules 102, 104 and 106.

The one or more processors 1004 may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and/or encoded logic operable to provide, either alone or in conjunction with other components of the first baseband unit 100, such as the memory 1006, network node functionality. For example, the one or more processors 1004 may execute instructions stored in the memory 1006. Such functionality may include providing various features and steps discussed herein, including any of the benefits disclosed herein. The expression "the device (e.g., the baseband unit) being operative to perform an action" may denote the first baseband unit 100 being configured to perform the action.

As schematically illustrated in Fig. 10, the first baseband unit 100 may be embodied by a first network node 150, e.g., standing in to serve one or more radio devices on radio resources of a second network node 250 in case a failure of the second network node 250 is determined. The first network node 150 comprises a radio interface 1002 coupled to the first baseband unit 100 for radio communication with one or more radio devices, e.g., within the second group of radio devices served on a second share of radio resources. The first network node 150 further comprises an interface 154 coupled to the first baseband unit 100 for communication with the second network node 250, e.g., for monitoring an operation of the second baseband unit 200 of the second network node 250.

Fig. 11 shows a schematic block diagram for an embodiment of the second baseband unit 200. The second baseband unit 200 comprises processing circuitry, e.g., one or more processors 1104 for performing the method 400 and memory 1106 coupled to the processors 1104. For example, the memory 1106 may be encoded with instructions that implement at least one of the modules 202 and 204.

The one or more processors 1104 may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and/or encoded logic operable to provide, either alone or in conjunction with other components of the second baseband unit 200, such as the memory 1106, network node functionality. For example, the one or more processors 1104 may execute instructions stored in the memory 1106. Such functionality may include providing various features and steps discussed herein, including any of the benefits disclosed herein. The expression "the device (e.g., the baseband unit) being operative to perform an action" may denote the second baseband unit 200 being configured to perform the action.

As schematically illustrated in Fig. 11, the second baseband unit 200 may be embodied by a second network node 250, e.g., failing operation to serve one or more radio devices on radio resources. The second network node 250 comprises a radio interface 1102 coupled to the second baseband unit 200 for radio communication with one or more radio devices, e.g., within the second group of radio devices served on a second share of radio resources. The second network node 250 further comprises an interface 254 coupled to the second baseband unit 200 for communication with the first network node 150, e.g., for sending heartbeat signaling and/or configuration information as to a configuration of the second baseband unit 200.

The first baseband unit 100 and the second baseband unit 200 may be identical. Alternatively or in addition, the first network node 150 (e.g., the first baseband unit 100) and/or the second network node 250 (e.g., the second baseband unit 200) may be configured to perform both methods 300 and 400.

With reference to Fig. 12, in accordance with an embodiment, a communication system 1200 includes a telecommunication network 1210, such as a 3GPP-type cellular network, which comprises an access network 1211, such as a radio access network, and a core network 1214. The access network 1211 comprises a plurality of base stations 1212a, 1212b, 1212c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 1213a, 1213b, 1213c. Each base station 1212a, 1212b, 1212c is connectable to the core network 1214 over a wired or wireless connection 1215. A first user equipment (UE) 1291 located in coverage area 1213c is configured to wirelessly connect to, or be paged by, the corresponding base station 1212c. A second UE 1292 in coverage area 1213a is wirelessly connectable to the corresponding base station 1212a. While a plurality of UEs 1291, 1292 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 1212.

Any of the base stations 1212 may embody the first baseband unit 100 and/or the second baseband unit 200. Alternatively or in addition, any of the UEs 1291, 1292 may embody the at least one radio device 506.

The telecommunication network 1210 is itself connected to a host computer 1230, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 1230 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 1221, 1222 between the telecommunication network 1210 and the host computer 1230 may extend directly from the core network 1214 to the host computer 1230 or may go via an optional intermediate network 1220. The intermediate network 1220 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 1220, if any, may be a backbone network or the Internet; in particular, the intermediate network 1220 may comprise two or more sub-networks (not shown).

The communication system 1200 of Fig. 12 as a whole enables connectivity between one of the connected UEs 1291, 1292 and the host computer 1230. The connectivity may be described as an over-the-top (OTT) connection 1250. The host computer 1230 and the connected UEs 1291, 1292 are configured to communicate data and/or signaling via the OTT connection 1250, using the access network 1211, the core network 1214, any intermediate network 1220 and possible further infrastructure (not shown) as intermediaries. The OTT connection 1250 may be transparent in the sense that the participating communication devices through which the OTT connection 1250 passes are unaware of routing of uplink and downlink communications. For example, a base station 1212 need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 1230 to be forwarded (e.g., handed over) to a connected UE 1291. Similarly, the base station 1212 need not be aware of the future routing of an outgoing uplink communication originating from the UE 1291 towards the host computer 1230.

By virtue of the method 300 and/or 400 being performed by any one of the base stations 1212, the performance or range of the OTT connection 1250 can be improved, e.g., in terms of increased throughput and/or reduced latency. More specifically, the host computer 1230 may indicate to the RAN 502, the network node 150 and/or the network node 250 (e.g., on an application layer) the QoS of the traffic and/or the need to provide the redundancy function for the traffic (e.g., the user data).

Example implementations, in accordance with an embodiment of the UE, base station and host computer discussed in the preceding paragraphs, will now be described with reference to Fig. 13. In a communication system 1300, a host computer 1310 comprises hardware 1315 including a communication interface 1316 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 1300. The host computer 1310 further comprises processing circuitry 1318, which may have storage and/or processing capabilities. In particular, the processing circuitry 1318 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer 1310 further comprises software 1311, which is stored in or accessible by the host computer 1310 and executable by the processing circuitry 1318. The software 1311 includes a host application 1312. The host application 1312 may be operable to provide a service to a remote user, such as a UE 1330 connecting via an OTT connection 1350 terminating at the UE 1330 and the host computer 1310. In providing the service to the remote user, the host application 1312 may provide user data, which is transmitted using the OTT connection 1350. The user data may depend on the location of the UE 1330. The user data may comprise auxiliary information (for the operation of a manufacturing machine) delivered to the UE 1330. The location may be reported by the UE 1330 to the host computer, e.g., using the OTT connection 1350, and/or by the base station 1320, e.g., using a connection 1360.

The communication system 1300 further includes a base station 1320 provided in a telecommunication system and comprising hardware 1325 enabling it to communicate with the host computer 1310 and with the UE 1330. The hardware 1325 may include a communication interface 1326 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 1300, as well as a radio interface 1327 for setting up and maintaining at least a wireless connection 1370 with a UE 1330 located in a coverage area (not shown in Fig. 13) served by the base station 1320. The communication interface 1326 may be configured to facilitate a connection 1360 to the host computer 1310. The connection 1360 may be direct, or it may pass through a core network (not shown in Fig. 13) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 1325 of the base station 1320 further includes processing circuitry 1328, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station 1320 further has software 1321 stored internally or accessible via an external connection.

The communication system 1300 further includes the UE 1330 already referred to. Its hardware 1335 may include a radio interface 1337 configured to set up and maintain a wireless connection 1370 with a base station serving a coverage area in which the UE 1330 is currently located. The hardware 1335 of the UE 1330 further includes processing circuitry 1338, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 1330 further comprises software 1331, which is stored in or accessible by the UE 1330 and executable by the processing circuitry 1338. The software 1331 includes a client application 1332. The client application 1332 may be operable to provide a service to a human or non-human user via the UE 1330, with the support of the host computer 1310. In the host computer 1310, an executing host application 1312 may communicate with the executing client application 1332 via the OTT connection 1350 terminating at the UE 1330 and the host computer 1310. In providing the service to the user, the client application 1332 may receive request data from the host application 1312 and provide user data in response to the request data. The OTT connection 1350 may transfer both the request data and the user data. The client application 1332 may interact with the user to generate the user data that it provides.

It is noted that the host computer 1310, base station 1320 and UE 1330 illustrated in Fig. 13 may be identical to the host computer 1230, one of the base stations 1212a, 1212b, 1212c and one of the UEs 1291, 1292 of Fig. 12, respectively. This is to say, the inner workings of these entities may be as shown in Fig. 13, and, independently, the surrounding network topology may be that of Fig. 12.

In Fig. 13, the OTT connection 1350 has been drawn abstractly to illustrate the communication between the host computer 1310 and the UE 1330 via the base station 1320, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE 1330 or from the service provider operating the host computer 1310, or both. While the OTT connection 1350 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

The wireless connection 1370 between the UE 1330 and the base station 1320 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 1330 using the OTT connection 1350, in which the wireless connection 1370 forms the last segment. More precisely, the teachings of these embodiments may reduce the latency and improve the data rate and thereby provide benefits such as better responsiveness and improved QoS.

A measurement procedure may be provided for the purpose of monitoring data rate, latency, QoS and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1350 between the host computer 1310 and UE 1330, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 1350 may be implemented in the software 1311 of the host computer 1310 or in the software 1331 of the UE 1330, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 1350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 1311, 1331 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station 1320, and it may be unknown or imperceptible to the base station 1320. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer's 1310 measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software 1311, 1331 causes messages to be transmitted, in particular empty or "dummy" messages, using the OTT connection 1350 while it monitors propagation times, errors etc.

Fig. 14 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figs. 12 and 13. For simplicity of the present disclosure, only drawing references to Fig. 14 will be included in this paragraph. In a first step 1410 of the method, the host computer provides user data. In an optional substep 1411 of the first step 1410, the host computer provides the user data by executing a host application. In a second step 1420, the host computer initiates a transmission carrying the user data to the UE. In an optional third step 1430, the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional fourth step 1440, the UE executes a client application associated with the host application executed by the host computer.

Fig. 15 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figs. 12 and 13. For simplicity of the present disclosure, only drawing references to Fig. 15 will be included in this paragraph. In a first step 1510 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In a second step 1520, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step 1530, the UE receives the user data carried in the transmission.

As has become apparent from above description, at least some embodiments of the technique allow for an improved reliability of a network (e.g., RAN) that does not suffer from capacity losses and/or minimizes service interruption in case of failure of a baseband unit of a network node. Alternatively or in addition, at least some embodiments of the technique allow for power saving and/or energy improvement at the network level (e.g., at a network node of the RAN) and/or at one or more radio devices served by the network (e.g., the RAN).

Many advantages of the present invention will be fully understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the units and devices without departing from the scope of the invention and/or without sacrificing all of its advantages. Since the invention can be varied in many ways, it will be recognized that the invention should be limited only by the scope of the following claims.

Claims

1. A method (300) of serving at least one radio device (506) by a first baseband unit (100) of a first network node (150) for compensating a failure of a second baseband unit (200) of a second network node (250) while serving the at least one radio device (506) on radio resources (256) of the second network node (250), the method (300) comprising or initiating the steps of: monitoring (302), at the first network node (150), an operation of the second baseband unit (200) of the second network node (250); and serving (306), by the first baseband unit (100), the at least one radio device (506) on the radio resources (256) of the second network node (250) responsive to determining a failure of the operation of the second baseband unit (200) at the first network node (150).

2. The method (300) of claim 1, wherein the monitoring (302) of the operation of the second baseband unit (200) comprises monitoring at least one of a heartbeat signaling from the second baseband unit (200); a backhaul communication of the second baseband unit (200) or the second network node (250); a baseband signal from the second baseband unit (200); and a radio frequency signal from the second network node (250), wherein the radio frequency signal comprises a baseband signal from the second baseband unit (200).

3. The method (300) of claim 1 or 2, further comprising or initiating the step of: receiving (304), at the first baseband unit (100) of the first network node (150) from the second baseband unit (200) of the second network node (250), configuration information as to a configuration of the second baseband unit (200) of the second network node (250).

4. The method (300) of claim 3, wherein the step of receiving (304) the configuration information comprises the step of monitoring (302) the operation of the second baseband unit (200), and wherein the failure of the second baseband unit (200) is determined by the absence of the configuration information.

5. The method (300) of claim 3 or 4, wherein the step of receiving (304) the configuration information comprises maintaining a status of the second baseband unit (200) at the first baseband unit (100), wherein the status of the second baseband unit (200) maintained at the first baseband unit (100) is updated according to the received configuration information.

6. The method (300) of any one of claims 3 to 5, wherein the received configuration information or the status of the second baseband unit (200) maintained at the first baseband unit (100) is indicative of at least one of: a context of the at least one radio device (506); a status of a packet data convergence protocol, PDPC, layer of the second baseband unit (200); and a status of a radio link control, RLC, layer of the second baseband unit (200).

7. The method (300) of any one of claims 3 to 6, wherein the configuration information is at least one of received (304) periodically and triggered by an event at the second baseband unit (200).

8. The method (300) of any one of claims 3 to 7, wherein the configuration information is received (304) over an interface (154) towards the second baseband unit (200) with a latency and/or a periodicity that is less than one radio frame or less than one subframe of the radio resources (256).

9. The method (300) of any one of claims 3 to 8, wherein a content of the received configuration information and/or a content of the status of the second baseband unit (200) maintained at the first baseband unit (100) depends on a link capacity of a link between the first baseband unit (100) and the second baseband unit (200) on which the configuration information is received.

10. The method (300) of claim 9, wherein the received configuration information and/or a content of the status of the second baseband unit (200) maintained at the first baseband unit (100) is indicative of: a context of the at least one radio device (506), if the link capacity is less than a first threshold; the context of the at least one radio device (506) and a status of a PDPC layer of the second baseband unit (200), if the link capacity is greater than the first threshold and less than a second threshold; and the context of the at least one radio device (506), the status of a PDPC layer of the second baseband unit (200), and a status of an RLC layer of the second baseband unit (200), if the link capacity is greater than the second threshold.

11. The method (300) of any one of claims 3 to 10, wherein the received configuration information or the status of the second baseband unit (200) maintained at the first baseband unit (100) is indicative of at least one of a scheduling of the at least one radio device (506) and a modulation and coding scheme used by the second baseband unit (200) for serving the at least one radio device (506) prior to the failure.

12. The method (300) of any one of claims 3 to 11, wherein the serving (306) is based on the received configuration information or the status of the second baseband unit (200) maintained at the first baseband unit (100).

13. The method (300) of any one of claims 1 to 12, wherein serving (306) the at least one radio device (506) on the radio resources (256) of the second network node (250) comprises the steps of: receiving, at the first network node (150) from a core network (504), control information and/or data for the at least one radio device (506) served (306) on the radio resources (256) by the second network node (250); and transmitting, from the first network node (150), the received control information and/or data to the at least one radio device (506) on the radio resources (256).

14. The method (300) of any one of claims 1 to 13, wherein serving (306) the at least one radio device (506) on the radio resources (256) of the second network node (250) comprises the steps of: receiving, at the first network node (150) from the at least one radio device (506) served (306) on the radio resources (256) by the second network node (250), control information and/or data; and sending, from the first network node (150) to a core network (504), the received control information and/or data.

15. The method (300) of any one of claims 1 to 14, wherein the first network node (150) and the second network node (250) operate in frequency division duplex, FDD, mode and/or time division duplex, TDD, mode.

16. The method (300) of any one of claims 1 to 15, wherein the radio resources (256) comprise at least one of frequency resources and time resources.

17. The method (300) of any one of claims 1 to 16, wherein the radio resources used by the first baseband unit (100) for serving a first group of radio devices prior to the failure of the second baseband unit (200) and the radio resources of the second baseband unit (200) used by the first baseband unit (100) for serving (306) a second group of radio devices including the at least one radio device (506) after the failure are equal in capacity.

18. The method (300) of any one of claims 1 to 17, further comprising the step of: sending heartbeat signaling from the first baseband unit (100) of the first network node (150) to the second network node (250).

19. The method (300) of any one of claims 1 to 18, further comprising the step of: sending configuration information as to a configuration of the first baseband unit (100) of the first network node (150) from the first baseband unit (100) of the first network node (150) to the second baseband unit (200) of the second network node (250).

20. A method (400) of preparing a first baseband unit (100) of a first network node (150) to serve at least one radio device (506) for compensating a failure of a second baseband unit (200) of a second network node (250) while serving the at least one radio device (506) on radio resources (256) of the second network node (250), the method (400) comprising or initiating the steps of: sending (402) heartbeat signaling from the second baseband unit (200) of the second network node (250) to the first network node (150); and sending (404) configuration information as to a configuration of the second baseband unit (200) of the second network node (250) from the second baseband unit (200) of the second network node (250) to the first baseband unit (100) of the first network node (150).

21. The method (400) of claim 20, further comprising or initiating any step, and/or comprising any feature, according to or corresponding to any one of claims 2 to 19.

22. A computer program product comprising program code portions for performing the steps of any one of the claims 1 to 19 or 20 to 21 when the computer program product is executed on one or more computing devices (1004; 1104; 1328), optionally stored on a computer-readable recording medium (1006; 1106).

23. A first baseband unit (100) for serving at least one radio device (506) by the first baseband unit (100) of a first network node (150) for compensating a failure of a second baseband unit (200) of a second network node (250) while serving the at least one radio device (506) on radio resources (256) of the second network node (250), the first baseband unit (100) being configured to: monitor, at the first network node (150), an operation of the second baseband unit (200) of the second network node (250); and serve, by the first baseband unit (100), the at least one radio device (506) on the radio resources (256) of the second network node (250) responsive to determining a failure of the operation of the second baseband unit (200) at the first network node (150).

24. The first baseband unit (100) of claim 23, further configured to perform the steps of any one of claims 2 to 19.

25. A second baseband unit (200) for preparing a first baseband unit (100) of a first network node (150) to serve at least one radio device (506) for compensating a failure of the second baseband unit (200) of a second network node (250) while serving the at least one radio device (506) on radio resources (256) of the second network node (250), the second baseband unit (200) being configured to: send heartbeat signaling from the second baseband unit (200) of the second network node (250) to the first network node (150); and send configuration information as to a configuration of the second baseband unit (200) of the second network node (250) from the second baseband unit (200) of the second network node (250) to the first baseband unit (100) of the first network node (150).

26. The second baseband unit (200) of claim 25, further configured to perform the steps of claim 20 or 21.

27. A first baseband unit (100) for serving at least one radio device (506) by the first baseband unit (100) of a first network node (150) for compensating a failure of a second baseband unit (200) of a second network node (250) while serving the at least one radio device (506) on radio resources (256) of the second network node (250), the first baseband unit (100) comprising memory (1006) operable to store instructions and processing circuitry (1004) operable to execute the instructions, whereby the first baseband unit (100) is operative to: monitor, at the first network node (150), an operation of the second baseband unit (200) of the second network node (250); and serve, by the first baseband unit (100), the at least one radio device (506) on the radio resources (256) of the second network node (250) responsive to determining a failure of the operation of the second baseband unit (200) at the first network node (150).

28. The first baseband unit (100) of claim 27, further operative to perform the steps of any one of claims 2 to 19.

29. A second baseband unit (200) for preparing a first baseband unit (100) of a first network node (150) to serve at least one radio device (506) for compensating a failure of the second baseband unit (200) of a second network node (250) while serving the at least one radio device (506) on radio resources (256) of the second network node (250), the second baseband unit (200) comprising memory (1106) operable to store instructions and processing circuitry (1104) operable to execute the instructions, whereby the second baseband unit (200) is operative to: send heartbeat signaling from the second baseband unit (200) of the second network node (250) to the first network node (150); and send configuration information as to a configuration of the second baseband unit (200) of the second network node (250) from the second baseband unit (200) of the second network node (250) to the first baseband unit (100) of the first network node (150).

30. The second baseband unit (200) of claim 29, further operative to perform the steps of claim 20 or 21.

31. A first network node (150; 1212; 1212a; 1212b; 1212c; 1320) configured to communicate with a second network node (250; 1212; 1212a; 1212b; 1212c; 1320) and a user equipment, UE (1291; 1292; 1330), the first network node (150; 1212; 1212a; 1212b; 1212c; 1320) comprising a radio interface (152; 154; 1327) and processing circuitry (1004; 1328) configured to execute the steps of any one of claims 1 to 19.

32. A second network node (250; 1212; 1212a; 1212b; 1212c; 1320), configured to communicate with a first network node (150; 1212; 1212a; 1212b; 1212c; 1320) and a user equipment, UE (1291; 1292; 1330), the second network node (250; 1212; 1212a; 1212b; 1212c; 1320) comprising a radio interface (252; 254; 1327) and processing circuitry (1104; 1328) configured to execute the steps of claim 20 or 21.

33. A communication system (1200; 1300) including a host computer (1230; 1310) comprising: processing circuitry (1318) configured to provide user data; and a communication interface (1316) configured to forward user data to a radio network (1210; 1211) for transmission to a user equipment, UE (1291; 1292; 1330); wherein the radio network (1210; 1211) comprises a first network node (150; 1212; 1212a; 1212b; 1212c; 1320) and a second network node (250; 1212; 1212a; 1212b; 1212c; 1320), wherein the first network node (150; 1212; 1212a; 1212b; 1212c; 1320) and the second network node (250; 1212; 1212a; 1212b; 1212c; 1320) are configured to communicate with the UE (1291; 1292; 1330), wherein the first network node (150; 1212; 1212a; 1212b; 1212c; 1320) comprises a radio interface (152; 154; 1327) and processing circuitry (1004; 1328) configured to execute the steps of any one of claims 1 to 19.

34. The communication system (1200; 1300) of claim 33, further including the UE (1291; 1292; 1330), wherein the UE (1291; 1292; 1330) comprises a radio interface (1337) and processing circuitry (1338).

35. The communication system (1200; 1300) of claim 33 or 34, wherein the second network node (250; 1212; 1212a; 1212b; 1212c; 1320) comprises a radio interface (252; 254; 1327) and processing circuitry (1104; 1328) configured to execute the steps of claim 20 or 21.

36. The communication system (1200; 1300) of any one of claims 33 to 35, wherein: the processing circuitry (1318) of the host computer (1230; 1310) is configured to execute a host application (1312), thereby providing the user data; and the processing circuitry (1338) of the UE (1291; 1292; 1330) is configured to execute a client application (1332) associated with the host application (1312).