TECHNICAL FIELD

Embodiments herein relate to wireless communication systems, such as cellular networks. In particular, methods and nodes for managing assistance information for mitigating interference, from a cell operated by an interfering network node, towards a first user equipment, e.g. served by another cell, are disclosed.

BACKGROUND

During the last few years cellular operators have started to offer mobile broadband based on Wideband Code Division Multiple Access (WCDMA)/ High Speed Packet Access (HSPA). Further, fuelled by Long Term Evolution (LTE)/LTE-Advanced (LTE-A) deployments and new devices designed for data applications, the end user performance requirements are steadily increasing. The large uptake of mobile broadband has resulted in that the traffic volume that needs to be handled by the HSPA/LTE/LTE-A networks has grown significantly. Therefore, techniques that allow cellular operators to manage their network more efficiently are of large importance. One such technique is deployment of Low Power Nodes (LPN) in a macro coverage area, which may be served by a macro node, or high power node. This type of deployment is called heterogeneous networks as opposed to homogeneous networks.

Homogeneous Networks

A homogeneous network is a network of base stations (Node B/eNodeB) in a planned layout and a collection of user terminals in which all base stations have similar transmit power levels (typically 43 -46 dBm), antenna patterns, receiver noise floors, and similar backhaul connectivity to the data network. Moreover, all base stations offer unrestricted access to user terminals in the network, and serve roughly the same number of user terminals. Current wireless system comes under this category for example Global System for Mobile communications (GSM), WCDMA, High Speed Downlink Packet Access (HSDPA), LTE , Worldwide Interoperability for Microwave Access (Wimax), etc.

Heterogeneous Networks

In heterogeneous networks, in addition to the planned or regular placement of macro base stations, several micro/pico/femto/relay/Remote Radio Units (RRU) nodes (commonly referred to as low power nodes (LPN)) are deployed as shown in Figure 1 , illustrating a typical deployment of low power nodes in heterogeneous networks. Note that the power transmitted by these LPNs is relatively small compared to that of macro base stations, e.g. 2W as compared to 40 W for a typical macro base station. The LPNs are deployed to eliminate coverage holes in the homogeneous networks (using macro base stations only) and to off-load the macro base station, thereby improving the capacity in hot-spot scenarios. Due to the lower transmit power and smaller physical size a LPN can offer flexible site acquisitions.

Deployed LPNs in a heterogeneous network can have the following properties:

1 . each LPN has its own cell identity (scrambling code). LPNs and Macro base stations operate different cells but they typically share the same frequency - referred to as co-channel deployment,

2. the LPNs have the same cell identities as the Macro Cell - referred to as soft or combined cell.

Figure 2 shows a further typical heterogeneous network with co-channel deployment, where the cells B and C are created by low power nodes in addition to the cell A created by a macro base station. Note that individual cell is characterized by individual pilots signal, downlink and uplink control channels and data traffic channels.

Figure 3 shows the heterogeneous network where low power nodes, i.e. cells operated by the low power nodes, are part of the macro cell. This is sometimes called as a soft cell or combined cell. This set up avoids the frequent soft handovers, hence higher layer signaling. Note that in this deployment all the nodes are coupled to the central node (in this case Macro base station) via high speed data link.

Figure 4 shows graphs of average sector throughput in Mbps vs. number of users per macro base station with 4 LPN with 37dBm and 30dBm power for WCDMA. It can be seen that at high load co-channel deployment gives significant gains because more users are offloaded. This is referred to as the gains due to load balancing.

Figure 5 shows a bar chart illustrating percentage of gain achieved with co-channel deployment. It can be observed that at low loads there is almost no gain and the gain increases as the load increases. The gain depends on the percentage of offloading.

Cell Range Expansion: Since the low power nodes have less transmit power, the number of users served by the LPNs are less compared to the macro base station. The gains in heterogeneous networks can be improved if more number of users are offloaded to the low power nodes. One technique to improve the overall system throughput is cell range expansion where the users are offloaded to the LPN by increasing the cell individual offsets (CIO). Figure 6 shows the cell range expansion area as a striped area (not checkered). In the cell range expansion area, the strongest cell is the macro cell. However if the LPN is less loaded than the macro cell, User Equipments (UEs) within the area can be served more often by the LPN, even though the throughput may be reduced due to the LPN not being the strongest cell. Since these UEs get scheduled more often when connected to the LPN, the overall throughput is higher.

In cell range expansion area, or cell range expansion zone, the UE is connected to LPN, and experiences a strong interference from high power node (HPN) e.g. macro network node. Figure 7 shows link level throughput in the cell expansion area when the UE is connected to LPN with different Macro interference values (l _oc ). It can be observed that the UE performance is severely impacted when the dominant interferer power is 10 -20 times that of received power from the LPN. It can be observed from above that there is huge performance degradation with the interference. The performance loss is in range of 100% at high geometries. Hence even though the UE is offloaded to the LPN, the individual UE throughput is impacted in the cell range expansion zone.

Figure 8 shows link performance if the interfering node signals the scheduling information to the victim UE, i.e. with network assistance. It can be seen that significant performance gains can be achieved if the victim UE knows the information about the interfering signals. In the simulation, the interference signal was re-constructed at the UE receiver and the interference is removed from after the detector output.

It can be seen from above figure that with network assistance it may be possible to almost mitigate the interference with a serial interference cancelation receiver. Such a receiver is commonly called as advanced receiver, enhanced receiver, interference mitigation receiver, interference cancellation receiver etc. Network assistance implies that some kind of assistance information may need to be signaled in a network, such as the above mentioned heterogeneous network. In this context, a problem may be what information to include in the assistance information.

SUMMARY

An object may thus be what information to signal as assistance information within networks of the above mentioned kind.

According to an aspect, the object is achieved by a method, performed by a first user equipment, for managing assistance information provided by a serving network node, wherein the serving network node serves the first user equipment. The first user equipment receives, from the serving network node, the assistance information, which includes a set of temporary identities for a set of second user equipments served by at least one cell operated by an interfering network node. Moreover, the first user equipment decodes information of a control channel, transmitted by the interfering network node, by means of the assistance information. Furthermore, the first user equipment uses the decoded information in order to mitigate interference, towards the first user equipment, from said at least one cell.

According to another aspect, the object is achieved by a first user equipment configured for managing assistance information provided by a serving network node, wherein the serving network node serves the first user equipment. The first user equipment is configured for receiving, from the serving network node, the assistance information, which includes a set of temporary identities for a set of second user equipments served by at least one cell operated by an interfering network node. Moreover, the first user equipment is configured for decoding information of a control channel, transmitted by the interfering network node, by means of the assistance information, and for using the decoded information in order to mitigate interference, towards the first user equipment, from said at least one cell.

According to a further aspect, the object is achieved by a method, performed by a serving network node, for managing assistance information. The serving network node obtains the assistance information, which includes a set of temporary identities for a set of second user equipments served by at least one cell operated by an interfering network node. Moreover, the serving network node sends the assistance information to a first user equipment, served by the serving network node, whereby the first user equipment is aided in mitigation of interference from said at least one cell.

According to a yet further aspect, the object is achieved by a serving network node configured for managing assistance information. The serving network node is configured for obtaining the assistance information, which includes a set of temporary identities for a set of second user equipments served by at least one cell operated by an interfering network node. Moreover, the serving network node is configured for sending the assistance information to a first user equipment, served by the serving network node, whereby the first user equipment is aided in mitigation of interference from said at least one cell.

According to a still other aspect, the object is achieved by a method, performed by an interfering network node, for managing assistance information. The interfering network node obtains assistance information including a set of temporary identities for a set of second user equipments served by at least one cell operated by the interfering network node. Furthermore, the interfering network node sends the assistance information to a serving network node, wherein the serving network node is capable of serving a first user equipment interfered by the at least one cell.

According to a yet other aspect, the object is achieved by an interfering network node configured for managing assistance information. The interfering network node is configured for obtaining assistance information including a set of temporary identities for a set of second user equipments served by at least one cell operated by the interfering network node. Furthermore, the interfering network node is configured for sending the assistance information to a serving network node, wherein the serving network node is capable of serving a first user equipment interfered by the at least one cell.

According to some embodiments herein, it is thus proposed to send the assistance information comprising at least the active user equipments (UEs), or a set of second user equipments, in one or more interfering cells to a serving network node (eNodeB/RNC). The set of second user equipments may e.g. be identified by temporary UE IDs, such as RNTIs. The active second UE herein means for example the UE(s) which is served by the interfering network node and maintain radio link or connection with the interfering network node. Such a second UE, or an aggressor UE, has been assigned a temporary UE IDentity (ID), such as RNTI, for communication with the interfering network node. The interfering network node may or not schedule the active second UE in every Transmit Time Interval (TTI), i.e. the interfering network node selects the temporary UE ID independently of whether or not the second UE, corresponding to the temporary UE ID, is scheduled or non- scheduled. The serving network node communicates, e.g. sends, the obtained assistance information to a first user equipment, e.g. using higher layer signaling. Once the first user equipment receives this information, the first user equipment may blindly decode the control channel of the interfering cell(s), operated by the interfering network node, by extracting all the parameters related to the interfering cell traffic channels. The interference from the received signal can thus be cancelled. The serving network node may serve the first user equipment.

With the embodiments herein, significant link level gains by using network assistance, i.e. using the assistance information for interference mitigation purposes, may be achieved, since the first user equipment decodes information of a control channel, transmitted by the interfering network node, by means of the received assistance information and further uses the decoded information in order to mitigate interference, towards itself, from said at least one cell. BRIEF DESCRIPTION OF THE DRAWINGS

The various aspects of embodiments disclosed herein, including particular features and advantages thereof, will be readily understood from the following detailed description and the accompanying drawings, in which:

Figure 1 is an overview of a heterogeneous network,

Figure 2 is a further overview of a further typical heterogeneous network with co- channel deployment,

Figure 3 is another overview of another heterogeneous network,

Figure 4 is a diagram illustrating graphs of average sector throughput,

Figure 5 is a bar chart illustrating percentage of gain in a co-channel deployment, Figure 6 is a yet further overview illustrating cell range expansion area,

Figure 7 is a diagram illustrating link level throughput in cell range expansion area, Figure 8 is a diagram illustrating link performance when interfering node signals scheduling information,

Figure 9 is a schematic overview of an exemplifying wireless communication network in which embodiments herein may be implemented,

Figure 10 is a combined signaling and flowchart illustrating the methods herein, Figure 1 1 is a sequence chart illustrating messages between a Node B and a user equipment,

Figure 12 is a block diagram illustrating downlink control channel processing, Figure 13 is a further block diagram illustrating an exemplifying interference cancellation receiver,

Figure 14 is an overview of a macro node and victim node in a network,

Figure 15 is a flowchart illustrating embodiments of the method in the first user equipment,

Figure 16 is a block diagram illustrating embodiments of the first user equipment, Figure 17 is a further flowchart illustrating embodiments of the method in the serving network node,

Figure 18 is a further block diagram illustrating embodiments of the serving network node,

Figure 19 is a yet further flowchart illustrating embodiments of the method in the interfering network node, and

Figure 20 is a yet further block diagram illustrating embodiments of the interfering network node.

DETAILED DESCRIPTION Throughout the following description similar reference numerals have been used to denote similar features, such as nodes, actions, steps, modules, circuits, parts, items elements, units or the like, when applicable. In the Figures, features that appear in some embodiments are indicated by dashed lines.

In order to better appreciate the embodiments herein, the following observations are made. While it may be possible to send the assistance information containing an entire set of information that can be used in the interfering node, this would lead to significant increase in signaling overheads on radio interface as well processing in the serving network node, interfering network nodes and UE. Furthermore, this may result in the increase in power consumption in the UE as it will have to process all possible combinations. It will also require more resources for transmission thereby reducing the throughput for the UEs in the interfering cell. This in turn reduces the overall system throughput and degrades system capacity.

Figure 9 depicts an exemplifying wireless communication network 100, in which embodiments herein may be implemented.

In this example, the wireless communication network 100 is a HSPA network or a Long Term Evolution (LTE) network. In other examples, the wireless communication network

100 may be any cellular or wireless communication system, such as a Global System for Mobile Communications (GSM), Universal Mobile Telecommunication System (UMTS) and Worldwide Interoperability for Microwave Access (WiMAX) or any other Third Generation Partnership Project (3GPP) communication network, or the like.

A first user equipment 101 may be located in a cell C1 , which is operated by a serving network node 1 10. The serving network node 1 10 serves the first user equipment

101 by operating the cell C1 . This may mean that the first user equipment 101 is connected, such as in RRC_CONNECTED mode, while using LTE terminology. The wireless

communication network comprises the serving network node 1 10.

The serving network node 1 10 may comprise a first network node 111 and/or a second network node 112. The first and/or second network nodes 1 1 1 , 1 12 may be a radio network node, a radio base station, a NodeB, an eNodeB, an RNC or the like. Similarly, the serving network node may be a radio network node, a radio base station, a NodeB, an eNodeB, an RNC or the like. Again, the serving network node 1 10 may be one of an access point, a base station, RNC, NodeB or eNodeB. The second network node 1 12 may be one of an access point, a base station, RNC, NodeB or eNodeB, a radio network node or the like. Furthermore, the wireless communication network 100 comprises an interfering network node 130, aka a third network node. The interfering network node 130 may be a High Power Node in relation to the serving network node 1 10, which thus may be a Low Power Node (LPN). In this context, as explained in the background section, high and/or low power refers to a level of transmit power of the serving network node 1 10 and the interfering network node 130.

The interfering network node 130 operates at least one cell C2, which may serve a set of second user equipments 105. Note that some embodiments herein are described assuming interference from only one neighboring cell, e.g. when the at least one cell C2 is only one cell. However, the methods outlined herein are equally applicable to cases in which the at least one cell C2 is more than one cells. The interfering network node 130 is called "interfering" network node 130, because the interfering network node 130 may operate the at least one cell C2 which may serve the set of second user equipments 105. Transmissions, e.g. control and/or payload data, from the at least one cell C2 to one or more second user equipments of the set of second user equipments 105, may interfere with transmissions, again e.g. control and/or payload data, from the cell C1 to the first user equipment 101 .

Accordingly, the interfering network node 130, or rather transmissions from the at least one cell C2 operated by the interfering network node 130, may cause interference towards the first user equipment 101 .

The interfering network node 130 may be one of an access point, a base station, RNC, NodeB or eNodeB, a radio network node or the like.

As used herein, the term "radio network node" may refer to an evolved Node B (eNB), a Radio Network Controller (RNC), a Radio Base Station (RBS), a control node controlling one or more Remote Radio Units (RRUs), an access point or the like.

As used herein, the term "user equipment" may refer to a wireless device, a machine- to-machine (M2M) device, a mobile phone, a cellular phone, a Personal Digital Assistant (PDA) equipped with radio communication capabilities, a smartphone, a laptop or personal computer (PC) equipped with an internal or external mobile broadband modem, a tablet PC with radio communication capabilities, a portable electronic radio communication device, a sensor device equipped with radio communication capabilities or the like. The sensor may be any kind of weather sensor, such as wind, temperature, air pressure, humidity etc. As further examples, the sensor may be a light sensor, an electronic or electric switch, a microphone, a loudspeaker, a camera sensor etc. The term "user" may indirectly refer to the wireless device. Sometimes, the term "user" may be used to refer to the user equipment or the like as above. It shall be understood that the user may not necessarily involve a human user. The term "user" may also refer to a machine, a software component or the like using certain functions, methods and similar.

Figure 10 illustrates an exemplifying method according to embodiments herein when performed in connection with the wireless communication network 100 of Figure 9.

The first user equipment 101 may perform a method for managing assistance information provided by a serving network node 1 10. The serving network node 1 10 may perform a method for managing assistance information. The interfering network node 130 may perform a method for managing assistance information.

The assistance information may be used for mitigating interference, from the at least one cell C2 caused by transmission, again by the at least one cell C2, to the set of second user equipments 105, towards the first user equipment 101 .

As mentioned, the serving network node 1 10 serves the first user equipment 101 .

One or more of the following actions may be performed in any suitable order. Action A010

The interfering network node 130 obtains assistance information including a set of temporary identities for a set 105 of second user equipments served by at least one cell C2 operated by the interfering network node 130.

The assistance information may include an index for a last temporary identity, being last in a sequence of temporary identities, which may be assigned to the set 105 of second user equipments in said at least one cell C2. As an example, the temporary identities of the sequence may be consecutive temporary identities. In more detail, as an example, it may be that the set of temporary identities includes only one temporary identity, such as 1234 and the index may be equal to 2. Then, the temporary identities of the set 105 of second user equipments would be 1234 (1234+0), 1235 (1234+1 ) and 1236 (1234+2).

Moreover, it may be that the assistance information includes one or more further indices for any temporary identity of the sequence that may not be assigned to any second user equipment served by the at least one cell C2. Continuing with the example directly above, said one or more further indices may be equal to 1 . Then, said one or more further indices would effectively remove 1235 (1234+1 ) from the set of temporary identities for the set 105 of second user equipments.

In one embodiment, the assistance information may include an index for a last temporary identity, being last in a sequence of temporary identities, which may be assigned to the set 105 of second user equipments in said at least one cell 02, and one or more further indices for any temporary identity of the sequence that may not be assigned to any second user equipment served by the at least one cell C2.

The set of temporary identities may include one or more RNTIs.

This may mean that the interfering network node 130 creates a list, e.g. the set of temporary identities, which includes one or more temporary identities, such as RNTIs, currently assigned to one or more second user equipments served by the at least one cell C2. As is well known, an RNTI uniquely identifies one 'second user equipment'.

Accordingly, some of the embodiments herein provide a solution that is power efficient and code efficient for conveying information about the aggressor UE, which - as mentioned above - is served by the interfering network node. Expressed differently, an advantage is that the assistance information including the set of temporary identities is efficiently coded and thus also efficiently conveyed.

Action A020

The interfering network node 130 sends the assistance information to a serving network node 1 10, wherein the serving network node 1 10 is capable of serving a first user equipment 101 interfered by the at least one cell C2.

The sending of the assistance information may comprise sending the assistance information using higher layer signaling, e.g. layer 3 or above, such as Radio Resource Control (RRC)-signaling or the like. The term "layer 3" is known from e.g. the Open

Systems Interconnection model (OSI) model.

Action A030

The serving network node 1 10 obtains the assistance information, which includes a set of temporary identities for a set 105 of second user equipments served by at least one cell C2 operated by an interfering network node 130.

The set of temporary identities of the assistance information may include a temporary identity for one 'second user equipment' of the set 105 of second user equipments, served by the interfering network node 130, that may have a geometry less than a pre-determined threshold, optionally the geometry relates to distance between the interfering network node 130 and said one 'second user equipment' of the set 105 of second user equipments in terms of radio conditions, such as a value of CSI.

This may mean that the set of temporary identities may form a first group and a second group, where the second group includes the temporary identities for which corresponding second user equipment may have a signal strength and/or downlink transmit power, which may be indicated by a geometry, that are less than their respective thresholds, and the remaining set of the second user equipment belong to the first group. Examples of signal strength are path loss, geometry factor, common pilot channel received signal code power (CPICH RSCP), reference signal received power (RSRP) etc. The threshold can be pre-defined, implementation specific or configured by the serving or interfering network nodes.

Expressed differently, the set of temporary identities of the assistance information may include at least one of a first group of temporary identities and a second group temporary identities, wherein the first group of temporary identities are associated with a first plurality of the set of second user equipments that are served by the interfering network node 130, that have a signal strength that is greater than or equal to a first signal strength threshold and/or a downlink transmit power that is less than or equal to a first DownLink (DL) transmit power threshold, and/or wherein the second group of temporary identities are associated with a second plurality of the set of second user equipments that are served by the interfering network node 130, that have a signal strength that is less than a second signal strength threshold and/or a downlink transmit power that is greater than or equal to a second transmit power threshold The downlink transmit power can be average power, maximum power, instantaneous power, e.g. in a slot or subframe, etc. The same value of each of the first and second thresholds is used for all of the set of second user equipments belonging to the same group, e.g. the first or second group. For example, assume there are two groups of the second user equipments. The thresholds for signal strength and DL transmit power can be -80 dBm and -3 dBm respectively. In this example, the second group of UEs may have signal strengths that are above or equal to -80 dBm and/or DL transmit powers that are less than or equal to -3 dBm. The remaining UEs of the set of second UEs will belong to the first group.

See further details below.

Action A040

The serving network node 1 10 sends the assistance information to a first user equipment 101 , served by the serving network node 1 10, whereby the first user equipment 101 is aided in mitigation of interference from said at least one cell C2.

The obtaining of the assistance information may comprise receiving the assistance information from the interfering network node 130.

The sending of the assistance information may comprise sending the assistance information using higher layer signaling, e.g. layer 3 or above, such as RRC-signaling or the like.

Action A041

The serving network node 1 10 may send the assistance information to a second network node 1 12. The sending of the assistance information may comprise sending the assistance information using higher layer signaling, e.g. layer 3 or above, such as RRC- signaling or the like.

In this manner, the assistance information received from the interfering network node 130 may be exchanged between various victim nodes, such as the first and/or second network nodes 1 1 1 , 1 12. Typically, a radio network node, e.g. the first network node 1 1 1 , may exchange the assistance information with a node that controls the radio network node, e.g. the second network node 1 12, such as an RNC.

Action A050

The first user equipment 101 receives, from the serving network node 1 10, the assistance information, which includes a set of temporary identities for a set 105 of second user equipments served by at least one cell C2 operated by an interfering network node 130.

The receiving of the assistance information may comprise receiving the assistance information using higher layer signaling, e.g. layer 3 or above, such as RRC-signaling or the like. Higher layer signaling may thus exclude signaling over Medium access control (MAC)-layer.

Action A060

The first user equipment 101 decodes information of a control channel, transmitted by the interfering network node 130, by means of the assistance information.

The decoding of information in the control channel may comprise decoding the information of at least one control channel for at least one specific temporary identity based on historical data, e.g. temporary identities stored in the memory, temporary identities most frequently and/or recently used for deciding the control channels, temporary identity used during the past decoding attempts.

For example, if the first user equipment 101 previously, e.g. within a certain preceding time period (e.g. one or more subframes such as over 5 subframes),

successfully decoded the information in the control channel for said at least one specific identity, then the first user equipment 101 may assume that the same specific identity, i.e. said at least one specific identity, will still be assigned to one of the set of second user equipments 105. Thereby, the first user equipment 101 may reduce the number of decoding attempts by first attempting to decode information in the control channel for the specific temporary identity, or those specific temporary identities, which previously was, or were, successfully decoded.

This may mean that the historical data may include said at least one specific identity for which the information in the control channel previously was successfully decoded. Action A070

The first user equipment 101 uses the decoded information in order to mitigate interference, towards the first user equipment 101 , from said at least one cell C2.

It is known in the art how the first user equipment 101 may use the decoded information to mitigate interference.

The embodiments above, and further embodiments herein, may include the following aspects and multiple embodiments thereof:

• Concept of interference mitigation, such as interference

cancellation, using higher layer signaling

• Methods to Reduce the payload at the neighbor cell assisting information

• Methods to reduce the search complexity at the UE

• Methods to convey the information using physical layer data The above embodiments are described in the following sections:

Concept of Interference mitigation, such as cancellation, e.g. using Higher Layer

Signaling

The scenario comprises of at least a UE served by a first cell, which in turn is served, or operated, by a first network node. The UE may be configured by the first network node to receive data with the first network node. In some cases the UE is configured by a second network node to receive data from the first network node. The data from the first network node is corrupted due to the interference from a third network node which in turn transmitting data to different UE(s) in the second cell.

In some embodiments the first and the second network nodes are the same e.g. eNode B in LTE. In some embodiments the first and the second network nodes are different e.g. Node B (or NodeB) and RNC are the first and the second network nodes, respectively, as in HSPA network. The first network node may also interchangeably be called as serving base station, serving node, serving network node or even serving radio network node of the UE. Note that in some embodiments the first and the third network node are connected using high speed link (LTE), and in some other embodiments the first and the third network node are connected via the second network node (HSPA).

In some embodiments the non-limiting term user equipment (UE) is used and it refers to any type of wireless device communicating with a network node in a cellular or mobile communication system over radio interface. Examples of UE are target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine communication, PDA, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, wireless device etc.

The terms interference mitigation receiver, interference cancellation receiver, interference suppression receiver, interference rejection receiver, interference aware receiver, interference avoidance receiver, or any combination thereof are interchangeably used but they all belong to a category of an advanced receiver or an enhanced receiver. Interference cancellation or suppression by such advanced receiver structures can lead to the elimination of the interference, in which case the interference is completely cancelled, whereas in other cases the impact of interference on the useful signal is reduced. Examples of signals or channels whose interference can be mitigated by the UE in LTE are Physical Downlink Shared Channel (PDSCH), Physical Downlink Control Channel (PDCCH), Physical Control format Indicator (PCFICH), EPDCCH, Physical Broadcast Channel (PBCH), CRS, PRS, etc. Examples of signals or channels whose interference can be mitigated by the UE in HSPA are High speed Physical data shared channel (HS- PDSCH), High speed shared control channel (HS-SCCH), P-CPICH, S-CPICH, DPCCH, F- DPCCH, etc.

In some embodiments the non-limiting term interfering cell is used. It is the cell, which is neighbor to the serving cell of the UE or to any cell measured by the UE, and from where UE receives at least certain type of interfering signals. Interfering cell is also interchangeably called as aggressor cell or dominant neighboring cell. The UE suffered from the interference may also be called as victim UE. The interfering cell is served by interfering network node i.e. third network node.

Figure 11 shows the typical message sequence chart, between a Node B and a UE, for the downlink data transfer in LTE/HSPA. From the pilots or reference signals, the UE computes the channel estimates then computes the parameters needed for channel state information (CSI) reporting. The CSI report consists for example channel quality indicator/information (CQI), precoding matrix index (PMI), rank information (Rl). The CSI report is sent to the eNodeB/Node B via a feedback channel either PUCCH (periodic CSI reporting) or PUSCH (aperiodic CSI reporting) or HS-DPCCH (periodic). The eNodeB/Node B scheduler uses this information in choosing the parameters for scheduling of this particular UE. The eNodeB/Node B sends the scheduling parameters to the UE in the downlink control channel called PDCCH/HS-SCCH. After that actual data transfer takes place from eNodeB/Node B to the UE.

Downlink Control Channel : Note that to decode the data traffic channel, the first UE 101 first needs to receive and decode PDCCH/HS-SCCH. The downlink control channel carries information about the scheduling grants. Typically this consist of number of MIMO layers scheduled, transport block sizes, modulation for each codeword, parameters related to Hybrid automatic repeat request (HARQ), sub band locations (e.g. for CSI estimation in case of LTE), rank and also PMI corresponding to that sub bands.

It shall here be said that the temporary identities of the set of temporary identities for the set of second user equipments is in the following exemplified by RNTI.

A Cyclic redundancy check (CRC) is attached to the each downlink control channel payload. The Radio Network Temporary Identifier (RNTI) is included in the CRC calculation and is not explicitly transmitted. The RNTI is an identity temporarily assigned to the first UE 101 by the first or the second network nodes for communication over radio interface. The RNTI is in contrast to first UE's permanent or intrinsic ID e.g. IMSI etc. The new UE's RNTI is assigned by the new serving cell upon cell change or by RNC in WCDMA. Note that the LTE specification defines various forms of RNTI depending on the purpose of downlink control information message. For normal unicast data transmission to a single UE, the terminal specific C-RNTI (cell specific -RNTI) is used in LTE and for HSPA, H-RNTI is used.

Upon reception of downlink control channel, the first UE will check the CRC using its C-RNTI/H-RNTI. Note that every UE will be assigned a unique C-RNTI/H-RNTI during the cell setup. The standard allows C-RNTI/H-RNTI values ranging from 0-FFFF (Hexadecimal), which are pre-defined. If the CRC checks, the message is declared to correctly received and intended for the UE.

Concept: The concept behind the proposed method is that the interfering network node 130 conveys, or sends, the assistance information including the set of active RNTI (C-RNTI/H-RNTI) to the victim node, such as the serving network node, in semi static manner. In case of semi static transmission, the assistance information including the set of active RNTI (C-RNTI/H-RNTI) is sent in the order of one or more radio frames. Typically, the semi static transmission is sent once every K number of radio frames or even once every L seconds e.g. K = 100, L = 2 etc. In yet another example, the semi static transmission is sent only when there is any change in the set of active RNTI (C-RNTI/H- RNTI). The interfering network node 130 is also interchangeably called as aggressor node. For example, it may send the assistance information to another network node (e.g. the first or second node) periodically or aperiodically. It may send information about the active RNTIs in the cell if there is any change in the number of assigned RNTIs (e.g. new RNTIs are assigned or released). The interfering network node 130 may also send differential information about the active RNTIs with respect to the previously indicated active RNTIs e.g. only newly assigned RNTIs or RNTIs not used any more. The interfering network node may send information of the UEs (position, CQI feedback information) in the interfering cells to the second network node (RNC) so that the RNC could construct the set of active RNTI of the interfering UEs.

In WCDMA/HSDPA, the second network node (RNC) may use the network planning and the cell relation information, for example overlapping cells, to construct the set of active RNTI to the first UE.

In WCDMA/HSDPA, the second network node (RNC) may use position information to construct the set of active RNTI of the interfering UEs to the first UE.

The victim node (first network node) or the Radio Network controller of the victim node, i.e. more generally the serving network node 1 10, after obtaining the assistance information about the RNTIs used in the cell served by the interfering network node by one or more of the following means:

- by receiving information directly from the interfering network node;

- by receiving information indirectly from the interfering network node via another node e.g. via second node or via core network node etc;

- by retrieving information from the memory of the first network node e.g. based on information received in the past, historical data, statistics etc.

The victim node (first network node) or the radio network controller of the victim node may obtain information about at least RNTIs used in at least one interfering cell. The victim node (first network node) may also obtain information about RNTIs used more than one interfering cells e.g. 2 closest interfering nodes.

The victim node or the radio network controller of the victim node may further obtain information about at least RNTIs used in at least one interfering cell on each carrier in case the victim node served two or more carriers e.g. in case of multi-carrier or carrier aggregation (CA).

The victim node (first network node) or the radio network controller of the victim node after obtaining the assistance information about the RNTIs used in one or more cells served, or operated, by the third network node(s), conveys this information via higher layer signaling to the victim UE (first UE) which is capable of mitigating interference received from one or more interfering cells. The assistance information about the RNTIs may be provided to the UE for each of the serving carrier in case the UE is configured with CA e.g. primary serving cell and one or more secondary serving cells. Note that the higher layer signaling can be periodic or aperiodic or event triggered. Examples of higher layer signaling are RRC etc.

In yet another exemplary embodiment the third network node may divide based on one or more criteria the RNTIs of the aggressor UEs served by the third network node into at least two groups: a first group and a second group. Examples of criteria are maximum or average or instantaneous UE transmit power, geometry or geometry factor, signal strength, signal quality of the UE, location of the UE etc. The geometry or geometry factor may be expressed in linear scale as a ratio of the signal received from the serving cell to the sum of interference received from one or more neighboring cells plus noise. For example, the first group may contain RNTIs of UEs close to the third network node whereas the second group may contain RNTIs of UEs which are not close to the third network node (e.g. in the cell border region). The third network node may determine whether a particular aggressor UE is close to the interfering network node or not based on for example UE positioning information. In yet another example this can be determined based on signal quality measurement performed by the aggressor UE on third network node e.g. it is close to a Base Station (BS) if any one or more of Signal-to-Noise-Ratio (SNR), Signal-to- Interference-and-Noise-Ratio (SINR), Channel Quality Indicator (CQI) or Reference Signal Received Quality (RSRQ) is above a threshold otherwise it is in cell border. In yet another example this can be determined based on downlink transmit power with which the aggressor UE is scheduled by the third network node e.g. aggressor UE is close to the base station (BS) if the transmit (Tx) power is below a threshold otherwise it is in cell border. The RNTIs may be tagged with their corresponding tag identities (e.g. group ID # 0 and # 1 for RNTIs in the first and the second groups respectively) and transmitted to other network nodes i.e. first and/or second network nodes. In one exemplary embodiment the first or the second network node may transmit RNTIs of both groups along with their group IDs to the victim UE. In this case the victim UE may use both groups or one of the groups for interference mitigation based on one or more criteria, which may be UE implementation specific, pre-defined or configured by the network, such as by the first and/or second network node. In yet another exemplary embodiment the first or the second network node based on one or more criteria may select RNTIs of one the groups for a particular victim UE and transmit the selected to the UE. Examples of criteria are location of victim UE, signal quality of victim UE, processing capability of victim UE, power consumption of the victim UE, battery life (i.e. level of charging in battery) of victim UE etc. For example if the victim UE is close to the serving BS (i.e. first network node or victim node), then the first or second network node may signal the RNTIs in the second group to the victim UE. This is because in this case the victim UE may receive severe interference due to transmissions towards the aggressor UEs (i.e. served by a higher power node) which are in the cell border of the aggressor BS. But for example if the victim UE is far from the serving BS (i.e. first network node or victim node) or in the cell border region, then the first or second network node may signal the RNTIs in both the first and the second group to the victim UE.

UE processing: Once the active set of RNTI's in the neighbor cell is known, the victim UE, tries to decode the downlink control information of its own cell and also the neighbor cell from the received signal. Note that it has to decode all the possibilities of neighbor-cell RNTI. The victim UE may further decode the downlink control information of two or more neighbor (aggressor) cells on each of the carrier in case the UE is provided assistance information for multiple aggressor cells. Figure 12 shows an example of downlink control channel processing of a neighbor cell in a UE. In more detail, the Figure shows decoding of the neighbor cell control channel from a set of N RNTI. N is an integer; 1 , 2, 3, ...

Once the victim UE knows the control channel information of the neighbor cell, it can start decoding the PDSCH/HS-PDSCH information of the neighbor cell. Figure 13 shows a block diagram of an exemplifying interference cancellation receiver. In this example, the UE decodes the PDSCH of its own cell as well as its neighbor cell or multiple neighbor cells. If the CRC for PDSCH of its own cell is a fail, then it reconstructs the neighbor cell PDSCH and removes this signal from the received signal and tries to decode its own cell PDSCH. The exemplifying interference cancellation receiver comprises a first and a second detector 1301 , 1306, a first and a second de-interleaver 1302, 1307, a first and a second channel decoder 1308, a first and a second transport block 1304, 1309, a CRC decision 1305, a decision box

1310. Moreover, the interference cancellation receiver comprises a further transport block

131 1 , a channel encoder 1312, an interleaver and modulator 1313, a spreading 1314 and a reconstruction 1315.

In yet another embodiment the victim UE may receive RNTIs in at least two groups (the first and the second groups) as described above. In this case, based on one or more criteria, the UE may decide whether to use all RNTIs or RNTIs of a particular group to decode their control channels and corresponding data channels for interference mitigation. Examples of criteria are signal quality measured with respect to serving cell and/or aggressor cell (e.g. CQI, RSRQ etc), UE battery life, current power consumption, processing capability of the UE etc. For example the victim UE may decide to use only the RNTIs in the second group for decoding control channels in the aggressor cell(s) provided: the victim UE is in close proximity to its serving BS and/or its battery power is below a threshold and/or it has limited processing capability and/or currently available hardware resources are limited etc. In yet another example the victim UE may decide to use the RNTIs in both groups if the victim UE is in the cell border of its own serving cell and/or its battery power is above a threshold and/or it has enough processing capability and/or current hardware resources are enough to process RNTIs of both groups etc. The victim UE may determine whether it is close to the serving base station or not based on for example signal measurements such as signal strength, signal quality, location etc. For example if its serving cell's CQI is below a threshold then the victim UE may assume it is in the cell border otherwise it may assume it is close to its serving BS. The thresholds can be UE implementation specific, pre-defined, or configured/signaled by the first or second network nodes etc.

Example embodiment 1 : A method performed in an interfering network node to collect all the active RNTI and passing this information to the serving network node, i.e. the first/second network node, for aiding interference mitigation for the first UE in that cell.

Example embodiment 2: A method performed in a serving network node to collect all the active RNTI information from an interfering network node and passing this information to the first UE for aiding interference cancellation, i.e. aiding the first UE when performing interference cancellation.

Example embodiment 3: A method performed in a first UE for receiving assistance information about the active RNTI information of an interfering network node (neighbor cell) and decoding the control channel information of a cell of the interfering network node thereby reconstructing a traffic channel of the cell of the interfering network node for aiding in interference cancellation.

Method in the interfering Network Node in Choosing the Active RNTI for Network

Assistance

According to the concept herein, the aggressor node communicates all the active RNTIS to the victim node. Note that the possible values of RNTI (C-RNTI or H-RNTI) ranges from 0-2 ¹⁶ . Communicating all possible values, e.g. the entire range, requires huge message transfers from each network node to the other network node. The huge payload transfer between the nodes can be reduced by the following methods:

Method 1 : In general, the eNode B/RNC (in HSPA), such as the interfering network node 130, allocate the C-RNTI/H-RNTI sequentially. For example starting from 1 , 2... etc. Whenever, the UE goes to idle, its RNTI will be removed from the active UE list. In this method, it is proposed to pass the information of the end C-RNTI/H-RNTI and the RNTI's which are removed from the active UE list. For example say the aggressor cell, e.g. Cell C2 operated by the interfering network node 130, has 40 UEs and say 3 ^rd and 20 ^th UEs are gone from active to Idle. Hence, the interfering network node 130 communicates, 40, 3 and 20 to the victim cell, such as cell C1 operated by the serving/first network node, either directly or via second network node. Alternatively, the interfering network node, instead of sending each RNTIs, could send a list of RNTI ranges (RNTI start, RNTI end), where each value between the (RNTI start, RNTI end) are the RNTIs for the interfering UEs.

Method 2: Note that network assistance interference cancellation is most effective if the victim UE is able to decode the data packet from the aggressor node (which is scheduled to the aggressor UE). If the victim UE can't decode this packet, the gains due to interference cancellation are usually smaller, or in some cases negligible. Hence, it is here proposed that the aggressor node (3 ^rd network node) communicates the C-RNTI/H-RNTI of those UEs whose geometry is less than G _th, where G _th is a pre-configured threshold. This is because if the aggressor node is serving a high geometry UE (closer to the aggressor node), then the victim UE, which is at or beyond the cell edge (served by the other node), usually cannot decode the data packet intended for the UE in the aggressor cell. This is explained by Figure 14, where the macro node (aggressor node) is serving UE's at location L7 to L12, and the victim node is serving UEs at location L1 to L6. Let's choose G _th such that only the RNTI information corresponding to the low geometry UEs for example L9, L12 are communicated to the victim cell.

Note that there are different techniques to compute the geometry of the UE in the macro cell. The geometry may relate to a distance between the third network node and the UE in terms of radio conditions, e.g. in the form of a CSI value or a CQI value. For example a. Based on CQI reporting by UE

In HSDPA/LTE, the UE reports a periodic or aperiodic CQI based on the pilot measurements. The Node B can identify the geometry by averaging the CQI reports over time.

b. Based on Uplink measurements

From the uplink measurements, for example UE traffic channels/control channels, the geometry of the UE may be determined based on received signal strength.

In WCDMA/HSDPA, the RNC ( the second network node) can configure the aggressor nodes (the third network node) with the threshold values. It could further request the aggressor nodes to report the list of the interfering UEs, or the related measurements/CQI result of the UE. Example embodiment 4 (or sub-embodiment of 1 ): A method performed in a interfering network node to choose the ending number of the RNTI range (active), i.e. a last number in the range of RNTIs , and the individual RNTIs which are removed from the active UE list, and communicating to the other network node (first network node) in aiding interference cancellation for the terminals served by the serving network node.

Example embodiment 5 (or sub-embodiment of 2): A method performed in a serving network node to collect all the ending number of the RNTI range (active), and the individual RNTIs which are removed from the active UE list in the 3 ^rd network node and passing this information to the UE for aiding interference cancellation.

Example embodiment 6 (or sub-embodiment of 3): A method performed in a first UE to receive information about the ending number of the RNTI range (active), and the individual RNTIs which are removed from the active UE list of a different network node (neighbor cell) and decoding the control channel information of the other cell active UEs thereby reconstructing the other cell traffic channel for aiding interference cancellation.

Example embodiment 7 (or sub-embodiment of 1 ): A method performed in an interfering network node to choose the RNTI (active) whose geometry is less than a predetermined threshold, and communicating to the serving network node for aiding interference cancellation for the first user equipment served by the serving network node.

Example embodiment 8 (or sub-embodiment of 2): A method performed in a serving network node to collect all the RNTI (active) whose geometry is less than a predetermined threshold, from the interfering network node and passing this information to the first UE for aiding interference cancellation.

Example embodiment 9 (or sub-embodiment of 3): A method performed in a first UE to receive information about the RNTI (active) whose geometry is less than a predetermined threshold, and decoding the control channel information of the other cell active UEs thereby reconstructing the other cell traffic channel for aiding interference cancellation.

Method to reduce the computational complexity in searching neighbor cell control channel

Note that according to the general concept outlined in section "Concept of Interference mitigation, such as cancellation, e.g. using Higher Layer Signaling", the UE needs to search all the possible active-RNTIs of the other cell. When the active UE list is big, the complexity in decoding for all the RNTIS might be prohibitive. The search complexity can be reduced by choosing only a subset of RNTIs initially. If the CRC of the RNTIs in the subset is fail, then the UE can use the exhaustive approach of the remaining RNTI. The subset can be chosen based on historical data. For example the UE can choose the RNTIs which are scheduled often in the neighbor cell. This information can be deduced by the UE autonomously or with the assistance from the serving node, e.g. the first/second network node, and the neighboring third network node.

Example embodiment 10: A method performed in a first UE to decode the control channels of specific RNTIs based on historical data by reconstructing the other cell traffic channel for aiding interference cancellation.

Method to Convey Information to the UE

Note that according to the general concept outlined in section "Concept of Interference mitigation, such as cancellation, e.g. using Higher Layer Signaling", the victim UE receives the information about the active RNTI in the neighbor cell(s) through higher layer signaling e.g. RRC. However, in certain cases, sending this information through higher layer signaling may not be possible. In these cases, it is proposed that the victim Node, such as the serving network node, communicates the assisting information through physical layer data. i.e. victim UE and the victim node can have a mutual understanding that for every M transport blocks scheduled, M+1 ^th transport block contains information about the active RNTIs or the embodiments outlined in section "Method in the interfering Network Node in Choosing the Active RNTI for Network Assistance" and section "Method to reduce the computational complexity in searching neighbor cell control channel" in the neighbor cell.

Example embodiment 11 : A method performed in a serving network node to collect the information about the active UE RNTIs and communicating to the UE using physical layer data for aiding interference cancellation.

Example embodiment 12: A method performed in the first UE for receiving information about the active UE RNTI in the neighbor cell and for decoding the control channels of the neighbor cell thereby reconstructing the other cell traffic channel for aiding interference cancellation.

The solution is described using the HSPA terminology, but the solutions herein are also applicable to LTE networks.

To summarize the detailed description above, the embodiments disclosed herein include a method in the UE, comprising e.g. the steps of:

receiving from a serving network node the assistance information containing at least RNTIs of UEs in one or more interfering cells,

decoding the control channels transmitted by the interfering cell based on the received assistance information, and

further using the decoded information about the control channels for one or more tasks e.g: further decoding or receiving one or more data channels in one or more interfering cells, and

mitigating the other cell interference from the received signal e.g. from one or more decoded data channels.

Moreover, the embodiments include a method in the serving network node (e.g. the first network node) comprising e.g. the steps of:

obtaining assistance information containing at least RNTIs of UEs in one or more interfering cells, and communicating the obtained assistance information to the UE.

Additionally, the embodiments herein include a method in an interfering network node, e.g. third network node, such as a macro node, comprising e.g. the steps of:

obtaining temporary identities (e.g. RNTIs) of one or more UEs served by the interfering network node, and

communicating the currently allocated RNTIs, or a subset of RNTIs, to another network node e.g. neighboring node or RNC.

At least some embodiments herein may solve a problem of how to efficiently signal the assistance information throughout a network, such as the above mentioned heterogeneous network. In particular, at least some embodiments may solve another problem of how to signal the assistance information from the macro network node to the LPN and from the LPM to the user equipment.

In Figure 15, a schematic flowchart of exemplifying methods in the first user equipment 101 is shown. Again, the same reference numerals as above have been used to denote the same or similar features, in particular the same reference numerals have been used to denote the same or similar actions. Accordingly, the first user equipment 101 performs a method for managing assistance information provided by a serving network node 1 10, wherein the serving network node 1 10 serves the first user equipment 101 .

One or more of the following actions may be performed in any suitable order.

Action A050

The first user equipment 101 receives, from the serving network node 1 10, the assistance information, which includes a set of temporary identities for a set 105 of second user equipments served by at least one cell C2 operated by an interfering network node 130.

Action A060

The first user equipment 101 decodes information of a control channel, transmitted by the interfering network node 130, by means of the assistance information.

Action A070

The first user equipment 101 uses the decoded information in order to mitigate interference, towards the first user equipment 101 , from said at least one cell C2.

The assistance information may include an index for a last temporary identity, being last in a sequence of temporary identities, which may be assigned to the set 105 of second user equipments in said at least one cell C2, and one or more further indices for any temporary identity of the sequence that may not be assigned to any second user equipment served by the at least one cell C2.

The set of temporary identities of the assistance information may include at least one of a first group of temporary identities and a second group temporary identities, wherein the first group of temporary identities are associated with a first plurality of the set of second user equipments that have a signal strength that is greater than or equal to a first signal strength threshold and/or that have a downlink transmit power that is less than a first downlink transmit power threshold, and/or the second group of temporary identities are associated with a second plurality of the set of second user equipments that have a signal strength that is less than a second signal strength threshold and/or that have a downlink transmit power that is greater than or equal to a second downlink transmit power threshold.

The decoding of information in the control channel may comprise decoding the information of at least one control channel for at least one specific temporary identity based on historical data, e.g. past decoding attempts.

The receiving of the assistance information may comprise receiving the assistance information using higher layer signaling, e.g. layer 3 or above, such as RRC-signaling or the like.

The set of temporary identities may include one or more RNTIs.

The serving network node 1 10 may be one of an access point, a base station, RNC, NodeB or eNodeB.

The interfering network node 130 may be one of an access point, a base station, RNC, NodeB or eNodeB.

With reference to Figure 16, a schematic block diagram of embodiments of the first user equipment 101 of Figure 9 is shown.

The first user equipment 101 may comprise a processing module 1601 , such as a means, one or more hardware modules and/or one or more software modules for performing the methods described herein.

The first user equipment 101 may further comprise a memory 1602. The memory may comprise, such as contain or store, a computer program 1603.

According to some embodiments herein, the processing module 1601 comprises, e.g. 'is embodied in the form of or 'realized by', a processing circuit 1604 as an exemplifying hardware module. In these embodiments, the memory 1602 may comprise the computer program 1603, comprising computer readable code units executable by the processing circuit 1604, whereby the first user equipment 101 is operative to perform the methods of Figure 10 and/or Figure 15.

In some other embodiments, the computer readable code units may cause the first user equipment 101 to perform the method according to Figure 10 and/or 15 when the computer readable code units are executed by the first user equipment 101 .

Figure 16 further illustrates a carrier 1605, or program carrier, which comprises the computer program 1603 as described directly above.

In some embodiments, the processing module 1601 comprises an Input/Output unit 1606, which may be exemplified by a receiving module and/or a sending module as described below when applicable.

In further embodiments, the processing module 1601 may comprise one or more of a receiving module 1610, a decoding module 1620, a using module 1630, as exemplifying hardware modules. In other examples, one or more of the aforementioned exemplifying hardware modules may be implemented as one or more software modules.

Thus, there is provided a first user equipment 101 configured for managing assistance information provided by a serving network node 1 10, wherein the serving network node 1 10 serves the first user equipment 101 .

According to the various embodiments described above, the first user equipment 101 , the processing module 1601 and/or the receiving module 1610 is configured for receiving, from the serving network node 1 10, the assistance information, which includes a set of temporary identities for a set 105 of second user equipments served by at least one cell C2 operated by an interfering network node 130.

The first user equipment 101 , the processing module 1601 and/or the decoding module 1620 is configured for decoding information of a control channel, transmitted by the interfering network node 130, by means of the assistance information.

The first user equipment 101 , the processing module 1601 and/or the using module 1630 is configured for using the decoded information in order to mitigate interference, towards the first user equipment 101 , from said at least one cell C2.

As mentioned above, the assistance information may include an index for a last temporary identity, being last in a sequence of temporary identities, which may be assigned to the set 105 of second user equipments in said at least one cell C2, and one or more further indices for any temporary identity of the sequence that may not be assigned to any second user equipment served by the at least one cell C2.

The set of temporary identities of the assistance information may include at least one of a first group of temporary identities and a second group temporary identities, wherein the first group of temporary identities are associated with a first plurality of the set of second user equipments that have a signal strength that is greater than or equal to a first signal strength threshold and/or that have a downlink transmit power that is less than a first downlink transmit power threshold, and/or the second group of temporary identities are associated with a second plurality of the set of second user equipments that have a signal strength that is less than a second signal strength threshold and/or that have a downlink transmit power that is greater than or equal to a second downlink transmit power threshold.

The first user equipment 101 , the processing module 1601 and/or the decoding module 1620 may be configured for decoding the information in the control channel by decoding the information of at least one control channel for at least one specific temporary identity based on historical data.

The receiving of the assistance information may comprise receiving the assistance information using higher layer signaling.

The set of temporary identities may include one or more RNTIs.

The serving network node 1 10 may be one of an access point, a base station, RNC, NodeB or eNodeB.

The interfering network node 130 may be one of an access point, a base station, RNC, NodeB or eNodeB.

In Figure 17, a schematic flowchart of exemplifying methods in the serving network node 1 10 is shown. Again, the same reference numerals as above have been used to denote the same or similar features, in particular the same reference numerals have been used to denote the same or similar actions. Accordingly, the serving network node 1 10 performs a method for managing assistance information.

One or more of the following actions may be performed in any suitable order.

Action A030

The serving network node 1 10 obtains the assistance information, which includes a set of temporary identities for a set 105 of second user equipments served by at least one cell C2 operated by an interfering network node 130.

The obtaining of the assistance information may comprise receiving the assistance information from the interfering network node 130.

Action A040

The serving network node 1 10 sends the assistance information to a first user equipment 101 , served by the serving network node 1 10, whereby the first user equipment 101 is aided in mitigation of interference from said at least one cell C2.

The sending of the assistance information may comprise sending the assistance information using higher layer signaling, e.g. layer 3 or above, such as RRC-signaling or the like.

Action A041

The serving network node 1 10 may send the assistance information to a second network node 1 12. The second network node 1 12 may be one of an access point, a base station, RNC, NodeB or eNodeB.

The sending of the assistance information may comprise sending the assistance information using higher layer signaling, e.g. layer 3 or above, such as RRC-signaling or the like.

As mentioned, the assistance information may include an index for a last temporary identity, being last in a sequence of temporary identities, which may be assigned to the set 105 of second user equipments in said at least one cell C2, and one or more further indices for any temporary identity of the sequence that may not be assigned to any second user equipment served by the at least one cell C2.

The set of temporary identities of the assistance information may include at least one of a first group of temporary identities and a second group temporary identities, wherein the first group of temporary identities are associated with a first plurality of the set of second user equipments that have a signal strength that is greater than or equal to a first signal strength threshold and/or that have a downlink transmit power that is less than a first downlink transmit power threshold, and/or the second group of temporary identities are associated with a second plurality of the set of second user equipments that have a signal strength that is less than a second signal strength threshold and/or that have a downlink transmit power that is greater than or equal to a second downlink transmit power threshold.

The serving network node 1 10 may comprise a first network node 1 1 1 and a second network node 1 12, wherein the first network node 1 1 1 may comprise a NodeB or an eNodeB.

The set of temporary identities may include one or more RNTIs.

The serving network node 1 10 may be one of an access point, a base station, RNC, NodeB or eNodeB.

The interfering network node 130 may be one of an access point, a base station, RNC, NodeB or eNodeB.

With reference to Figure 18, a schematic block diagram of embodiments of the serving network node 1 10 of Figure 9 is shown.

The serving network node 1 10 may comprise a processing module 1801 , such as a means, one or more hardware modules and/or one or more software modules for performing the methods described herein.

The serving network node 1 10 may further comprise a memory 1802. The memory may comprise, such as contain or store, a computer program 1803.

According to some embodiments herein, the processing module 1801 comprises, e.g. 'is embodied in the form of or 'realized by', a processing circuit 1804 as an exemplifying hardware module. In these embodiments, the memory 1802 may comprise the computer program 1803, comprising computer readable code units executable by the processing circuit 1804, whereby the serving network node 1 10 is operative to perform the methods of Figure 10 and/or Figure 17. In some other embodiments, the computer readable code units may cause the serving network node 1 10 to perform the method according to Figure 10 and/or 17 when the computer readable code units are executed by the serving network node 1 10.

Figure 18 further illustrates a carrier 1805, or program carrier, which comprises the computer program 1803 as described directly above.

In some embodiments, the processing module 1801 comprises an Input/Output unit 1806, which may be exemplified by a receiving module and/or a sending module as described below when applicable.

In further embodiments, the processing module 1801 may comprise one or more of an obtaining module 1810, a sending module 1820, as exemplifying hardware modules. In other examples, one or more of the aforementioned exemplifying hardware modules may be implemented as one or more software modules.

Thus, there is provided a serving network node 1 10 configured for managing assistance information.

According to the various embodiments described above, the serving network node 1 10, the processing module 1801 and/or the obtaining module 1810 is configured for obtaining the assistance information, which includes a set of temporary identities for a set 105 of second user equipments served by at least one cell C2 operated by an interfering network node 130.

The serving network node 1 10, the processing module 1801 and/or the sending module 1820 is configured for sending the assistance information to a first user equipment 101 , served by the serving network node 1 10, whereby the first user equipment 101 is aided in mitigation of interference from said at least one cell C2.

The serving network node 1 10, the processing module 1801 and/or the obtaining module 1810 may be configured for obtaining the assistance information by receiving the assistance information from the interfering network node 130.

The serving network node 1 10, the processing module 1801 and/or the sending module 1820 may be configured for sending the assistance information to a second network node 1 12.

The second network node 1 12 may be one of an access point, a base station, RNC, NodeB or eNodeB.

The assistance information may include an index for a last temporary identity, being last in a sequence of temporary identities, which may be assigned to the set 105 of second user equipments in said at least one cell C2, and one or more further indices for any temporary identity of the sequence that may not be assigned to any second user equipment served by the at least one cell C2.

The set of temporary identities of the assistance information may include at least one of a first group of temporary identities and a second group temporary identities, wherein the first group of temporary identities are associated with a first plurality of the set of second user equipments that have a signal strength that is greater than or equal to a first signal strength threshold and/or that have a downlink transmit power that is less than a first downlink transmit power threshold, and/or the second group of temporary identities are associated with a second plurality of the set of second user equipments that have a signal strength that is less than a second signal strength threshold and/or that have a downlink transmit power that is greater than or equal to a second downlink transmit power threshold.

The serving network node 1 10 may be configured for sending the assistance information by sending the assistance information using higher layer signaling.

The serving network node 1 10 may comprise a first network node 1 1 1 and a second network node 1 12, wherein the first network node 1 1 1 may comprise a NodeB or an eNodeB.

The set of temporary identities may include one or more RNTIs.

The serving network node 1 10 may be one of an access point, a base station, RNC, NodeB or eNodeB.

The interfering network node 130 may be one of an access point, a base station, RNC, NodeB or eNodeB.

In Figure 19, a schematic flowchart of exemplifying methods in the interfering network node 130 is shown. Again, the same reference numerals as above have been used to denote the same or similar features, in particular the same reference numerals have been used to denote the same or similar actions. Accordingly, the interfering network node 130 performs a method for managing assistance information.

One or more of the following actions may be performed in any suitable order.

Action A010

The interfering network node 130 obtains assistance information including a set of temporary identities for a set 105 of second user equipments served by at least one cell C2 operated by the interfering network node 130.

Action A020 The interfering network node 130 sends the assistance information to a serving network node 1 10, wherein the serving network node 1 10 is capable of serving a first user equipment 101 interfered by the at least one cell C2.

As mentioned, the assistance information may include an index for a last temporary identity, being last in a sequence of temporary identities, which may be assigned to the set 105 of second user equipments in said at least one cell C2, and one or more further indices for any temporary identity of the sequence that may not be assigned to any second user equipment served by the at least one cell C2.

The set of temporary identities of the assistance information may include at least one of a first group of temporary identities and a second group temporary identities, wherein the first group of temporary identities are associated with a first plurality of the set of second user equipments that have a signal strength that is greater than or equal to a first signal strength threshold and/or that have a downlink transmit power that is less than a first downlink transmit power threshold, and/or the second group of temporary identities are associated with a second plurality of the set of second user equipments that have a signal strength that is less than a second signal strength threshold and/or that have a downlink transmit power that is greater than or equal to a second downlink transmit power threshold.

The set of temporary identities may include one or more RNTIs.

The interfering network node 130 may be one of an access point, a base station, RNC, NodeB or eNodeB.

The sending of the assistance information may comprise sending the assistance information using higher layer signaling, e.g. layer 3 or above, such as RRC-signaling or the like.

With reference to Figure 20, a schematic block diagram of embodiments of the interfering network node 130 of Figure 9 is shown.

The interfering network node 130 may comprise a processing module 2001 , such as a means, one or more hardware modules and/or one or more software modules for performing the methods described herein.

The interfering network node 130 may further comprise a memory 2002. The memory may comprise, such as contain or store, a computer program 2003.

According to some embodiments herein, the processing module 2001 comprises, e.g. 'is embodied in the form of or 'realized by', a processing circuit 2004 as an exemplifying hardware module. In these embodiments, the memory 2002 may comprise the computer program 2003, comprising computer readable code units executable by the processing circuit 2004, whereby the interfering network node 130 is operative to perform the methods of Figure 10 and/or Figure 19.

In some other embodiments, the computer readable code units may cause the interfering network node 130 to perform the method according to Figure 10 and/or 19 when the computer readable code units are executed by the interfering network node 130.

Figure 20 further illustrates a carrier 2005, or program carrier, which comprises the computer program 2003 as described directly above.

In some embodiments, the processing module 2001 comprises an Input/Output unit 2006, which may be exemplified by a receiving module and/or a sending module as described below when applicable.

In further embodiments, the processing module 2001 may comprise one or more of a obtaining module 2010, a sending module 2020, a receiving module 2030, as

exemplifying hardware modules. In other examples, one or more of the aforementioned exemplifying hardware modules may be implemented as one or more software modules.

According to the embodiments herein, the interfering network node 130 is thus configured for managing assistance information.

With the various embodiments described above, the interfering network node 130, the processing module 2001 and/or the obtaining module 2010 is configured for obtaining assistance information including a set of temporary identities for a set 105 of second user equipments served by at least one cell C2 operated by the interfering network node 130.

Moreover, the interfering network node 130, the processing module 2001 and/or the sending module 2020 is configured for sending the assistance information to a serving network node 1 10, wherein the serving network node 1 10 is capable of serving a first user equipment 101 interfered by the at least one cell C2.

The interfering network node 130, the processing module 2001 and/or the receiving module 2030 may be configured for receiving a request from the serving network node 1 10; and wherein the interfering network node 130, the processing module 2001 and/or the sending module 2020 may be configured for sending the assistance information in response to the request.

As mentioned, the assistance information may include an index for a last temporary identity, being last in a sequence of temporary identities, which may be assigned to the set 105 of second user equipments in said at least one cell C2, and one or more further indices for any temporary identity of the sequence that may not be assigned to any second user equipment served by the at least one cell C2.

The set of temporary identities of the assistance information may include at least one of a first group of temporary identities and a second group temporary identities, wherein the first group of temporary identities are associated with a first plurality of the set of second user equipments that have a signal strength that is greater than or equal to a first signal strength threshold and/or that have a downlink transmit power that is less than a first downlink transmit power threshold, and/or the second group of temporary identities are associated with a second plurality of the set of second user equipments that have a signal strength that is less than a second signal strength threshold and/or that have a downlink transmit power that is greater than or equal to a second downlink transmit power threshold.

The set of temporary identities may include one or more RNTIs.

The interfering network node 130 may be one of an access point, a base station, RNC, NodeB or eNodeB.

The interfering network node 130 may be configured for sending the assistance information by sending the assistance information using higher layer signaling.

As used herein, the term "node", or "network node", may refer to one or more physical entities, such as devices, apparatuses, computers, servers or the like. This may mean that embodiments herein may be implemented in one physical entity. Alternatively, the embodiments herein may be implemented in a plurality of physical entities, such as an arrangement comprising said one or more physical entities, i.e. the embodiments may be implemented in a distributed manner.

As used herein, the term "unit" may refer to one or more functional units, each of which may be implemented as one or more hardware modules and/or one or more software modules in a node.

As used herein, the term "program carrier" may refer to one of an electronic signal, an optical signal, a radio signal, and a computer readable medium. In some examples, the program carrier may exclude transitory, propagating signals, such as the electronic, optical and/or radio signal. Thus, in these examples, the carrier may be a non-transitory carrier, such as a non-transitory computer readable medium.

As used herein, the term "processing module" may include one or more hardware modules, one or more software modules or a combination thereof. Any such module, be it a hardware, software or a combined hardware-software module, may be a determining means, estimating means, capturing means, associating means, comparing means, identification means, selecting means, receiving means, sending means or the like as disclosed herein. As an example, the expression "means" may be a module corresponding to the modules listed above in conjunction with the Figures.

As used herein, the term "software module" may refer to a software application, a Dynamic Link Library (DLL), a software component, a software object, an object according to Component Object Model (COM), a software component, a software function, a software engine, an executable binary software file or the like.

As used herein, the term "processing circuit" may refer to a processing unit, a processor, an Application Specific integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA) or the like. The processing circuit or the like may comprise one or more processor kernels.

As used herein, the expression "configured to", or "configured for", may mean that a processing circuit is configured to, or adapted to, by means of software configuration and/or hardware configuration, perform one or more of the actions described herein.

As used herein, the term "action" may refer to an action, a step, an operation, a response, a reaction, an activity or the like.

As used herein, the term "memory" may refer to a hard disk, a magnetic storage medium, a portable computer diskette or disc, flash memory, random access memory (RAM) or the like. Furthermore, the term "memory" may refer to an internal register memory of a processor or the like.

As used herein, the term "computer readable medium" may be a Universal Serial Bus (USB) memory, a DVD-disc, a Blu-ray disc, a software module that is received as a stream of data, a Flash memory, a hard drive, a memory card, such as a MemoryStick, a Multimedia Card (MMC), Secure Digital (SD) card, etc.

As used herein, the term "computer readable code units" may be text of a computer program, parts of or an entire binary file representing a computer program in a compiled format or anything there between.

As used herein, the term "radio resource" may refer to a certain coding of a signal and/or a time frame and/or a frequency range in which the signal is transmitted. In some examples, a resource may refer to one or more Physical Resource Blocks (PRB) which is used when transmitting the signal. In more detail, a PRB may be in the form of Orthogonal Frequency Division Multiplexing (OFDM) PHY resource blocks (PRB). The term "physical resource block" is known from 3GPP terminology relating to e.g. Long Term Evolution Systems. As used herein, the terms "number" and/or "value" may be any kind of digit, such as binary, real, imaginary or rational number or the like. Moreover, "number" and/or "value" may be one or more characters, such as a letter or a string of letters. "Number" and/or "value" may also be represented by a bit string.

As used herein, the term "set of" may refer to one or more of something. E.g. a set of devices may refer to one or more devices, a set of parameters may refer to one or more parameters or the like according to the embodiments herein.

As used herein, the expression "in some embodiments" has been used to indicate that the features of the embodiment described may be combined with any other embodiment disclosed herein.

Even though embodiments of the various aspects have been described, many different alterations, modifications and the like thereof will become apparent for those skilled in the art. The described embodiments are therefore not intended to limit the scope of the present disclosure.