WO2016050316A1

WO2016050316A1 - Methods and network nodes in a wireless communication network for handling of uplink signals sent by a user equipment

Info

Publication number: WO2016050316A1
Application number: PCT/EP2014/071233
Authority: WO
Inventors: Pär ANKEL; Billy Hogan; Erik Larsson
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2014-10-03
Filing date: 2014-10-03
Publication date: 2016-04-07

Abstract

Disclosed is a method performed by a non-serving network node (101) of a wireless communication network (100) for handling uplink signals sent by a UE (110) wherein the wireless communication network further comprises a serving network node (102) responsible for transmitting downlink signals to the UE (110), and wherein the non-serving network node (101) is capable of receiving uplink signals sent by the UE (110). The method comprises receiving, from the serving network node or from an RNC (120) to which the non-serving network node is connected, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH, dedicated for the UE. The method further comprises receiving the uplink signal from the UE, receiver processing the received uplink signal based on the received information enabling receiver processing to obtain the information representing the HS-DPCCH, and sending the obtained information representing the HS-DPCCH to the serving network node or the RNC.

Description

METHODS AND NETWORK NODES IN A WIRELESS COMMUNICATION NETWORK FOR HANDLING OF UPLINK SIGNALS SENT BY A USER

EQUIPMENT

Technical field

[0001 ]The present invention relates generally to methods and network nodes in a wireless communication network for handling of uplink signals sent by a user equipment. More specifically, the present invention relates to methods and network nodes for enabling uplink signals sent from a user equipment to reach a serving network node.

Background art

[0002] In wireless communication networks built on technologies such as Wideband Code Division Multiple Access, W-CDMA, High Speed Packet Access, HSPA comprising High Speed Downlink Packet Access, HSDPA, for downlink and High Speed Uplink Pack Access, HSUPA, also called Enhanced Uplink concept, EUL, for uplink, soft handover, SHO, also referred to as macro diversity, and fast closed-loop power control are essential features for providing uninterrupted and seamless coverage to user equipments, UEs, travelling across cell borders.

Figures 1 a and 1 b illustrate a traditional HSPA deployment scenario with a first and a second base station 101 , 102 having a similar transmit power level. Ideally, a UE 1 10 moving from a serving cell of the first base station 101 towards a non- serving cell of the second base station 102 (the movement illustrated with an arrow in fig. 1 a) would enter a SHO region at border A. At border B where the UE experiences approximately the same reception power for signals received from the first base station as for signals received from the second base station, a serving cell change would occur, such that non-serving cell becomes serving cell and vice versa. Further, at border C the UE 1 10 would leave the SHO region and only have connection to the second base station 102. It is a radio network controller, controlling the first 101 and the second base station 102 that is in control of reconfigurations, which implies rather long delays for e.g. performing such a cell change. During SHO, the UE is essentially power-controlled by the best uplink P43302 base station due to the "DOWN-before-UP" principle, i.e. it is enough that one base station indicates a DOWN command for the UE to lower its power. Since the base stations have roughly the same transmit power, the optimal downlink, DL, and uplink, UL, cell borders will coincide at point B. UL cell border is defined as the place where the path loss from the UE to the first base station will be equal the path loss from the UE to the second base station. Hence, in an ideal setting and from a static (long-term fading) point of view, the serving cell would always correspond to the best uplink. However, in practice, due to imperfections, e.g. reconfiguration delays, and fast fading, the UE might be power controlled solely by the non-serving base station during SHO. In such case there might be problems to receive essential control channel information from the UE in the serving base station due to the weaker link between the serving base station and the UE. For example, a Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH, and scheduling information need to be received in the serving base station. This problem becomes more pronounced in deployments with significant link imbalances, e.g. heterogeneous networks or multiflow.

[0003] Deployment of low-power nodes, LPNs, is seen as a powerful tool to meet the ever-increasing demand for mobile broadband services. A LPN may correspond, for example, to a remote radio unit, RRU, pico base station or micro base station, allowing expanding the network capacity in a cost-efficient way. A LPN is defined as having a lower output power than a high power node, HPN. The HPN may be a macro base station in a system where the LPNs are micro or pico base stations. A network consisting of such HPNs and LPNs is referred to as a heterogeneous network. Two examples of use-cases for heterogeneous network deployment that may be envisioned are coverage holes and capacity

enhancement for localized traffic hotspots.

[0004] Since the LPNs and the HPNs in a heterogeneous network have different transmit powers, the UL and DL cell borders will normally not coincide. Such an example is shown in figures 2a and 2b where the UE 1 10 when it is in the region between equal path loss border D and equal downlink received power border E

P43302 has a smaller path loss to the LPN, while the strongest received power is from the HPN. In such a scenario, the UL is better served by the non-serving LPN 101 while the DL is provided by the serving HPN 102. The region between the equal path loss border D and equal downlink received power (e.g. CPICH receive power) border E is referred to as an imbalance region. Further in fig. 2b there is a SHO region between borders F and G in which the UE is in soft handover, i.e.

connected to both the HPN and the LPN. In the region between E and G, the LPN is the serving node. In the region between E and F, the HPN is the serving node. In the imbalance region some fundamental problems may be encountered. For example, a UE in the region between borders E and F, i.e. in the SHO region but also in the imbalance region, would have the HPN 102 as the serving network node, but in general be power controlled towards the LPN 101 . Due to the UL-DL imbalance, the UL towards the serving HPN would be very weak, which means that important control information, such as scheduling information or HS-DPCCH, might not be reliably decoded by the serving HPN. Furthermore, a UE in between borders D and F would have the HPN as the serving network node, and also be power controlled towards the HPN (i.e. not in SHO). Due to the UL-DL imbalance, the UE would cause excessive interference in the LPN node.

[0005] A current solution to the imbalance problem is to increase the signal strength in UL enough so that the HPN when it is the serving network node can decode the signal also when the UE is in the imbalance region. This may be performed by either increasing the Signal to Interference Ratio, SIR, target in the LPN or by adding noise in the LPN. However, this causes high interference in the LPN.

[0006] Consequently, a severe negative impact on DL and UL scheduling is foreseen due to unreliable reception of UL signals when in such imbalance regions. Also, a more unpredictable/uncontrolled interference characteristic in the network is a direct consequence if nothing is done. All in all, a potentially severe network impact and end-user impact can be envisioned. As shown, there is a need for a solution to handle such imbalance problems.

P43302 Summary of invention

[0007] It is an object of the invention to address at least some of the problems and issues outlined above. It is possible to achieve these objects and others by using a method and an apparatus as defined in the attached independent claims.

[0008] An object of the present invention is to make it possible for a serving network node to get access to UL signals sent by a UE on a HS-DPCCH dedicated for the UE even though the UL signals are too weak for a good reception at the serving network node and without having to produce high interference in the non-serving node. Another object is to improve communication of HS-DPCCH signals when in soft handover without having to increase signal level of the uplink HS-DPCCH signals.

[0009] This is achieved by the serving network node sending information to the non-serving network node that makes it possible for the non-serving network node to receiver process the HS-DPCCH signals such that the non-serving network node can send receiver processed HS-DPCCH signals to the serving network node.

[00010] According to an aspect, a method is provided performed by a non- serving network node of a wireless communication network for handling uplink signals sent by a UE. The wireless communication network further comprises a serving network node responsible for transmitting downlink signals to the UE. The non-serving network node is capable of receiving uplink signals sent by the UE. The method comprises receiving, from the serving network node or from an RNC to which the non-serving network node is connected, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a HS-DPCCH, dedicated for the UE. The method further comprises receiving the uplink signal from the UE, receiver processing the received uplink signal based on the received information enabling receiver processing to obtain the information representing the HS- DPCCH, and sending the obtained information representing the HS-DPCCH to the serving network node or the RNC.

P43302 [0001 1 ] According to another aspect, a method is provided performed by a serving network node or a radio network controller of a wireless communication network for handling uplink signals sent by a UE. The serving network node is responsible for transmitting downlink signals to the UE. The wireless

communication network further comprises a non-serving network node capable of receiving uplink signals from the UE. The method comprises sending, to the non- serving network node, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a HS-DPCCH, and receiving from the non-serving network node, the information representing the HS-DPCCH, which information has been obtained by the non-serving network node by receiver processing the received uplink signal based on the received information enabling receiver processing.

[00012] According to another aspect, a non-serving network node of a wireless communication network is provided. The non-serving network node is operable for handling uplink signals sent by a UE. The wireless communication network further comprises a serving network node responsible for transmitting downlink signals to the UE. The non-serving network node is capable of receiving uplink signals sent by the UE. The non-serving network node comprises a processor and a memory, said memory containing instructions executable by said processor, whereby the non-serving network node is operative for receiving, from the serving network node or from an RNC to which the non-serving network node is connected, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a HS- DPCCH. Said memory further contains instructions executable by said processor, whereby the non-serving network node is operative for receiving the uplink signal from the UE, receiver processing the received uplink signal based on the received information enabling receiver processing to obtain the information representing the HS-DPCCH and sending the obtained information representing the HS-DPCCH to the serving network node or the RNC.

P43302 [00013] According to another aspect is provided a serving network node or an RNC connected to the serving network node of a wireless communication network, operable for handling uplink signals sent by a UE. The serving network node is responsible for transmitting downlink signals to the UE. The wireless

communication network further comprises a non-serving network node capable of receiving uplink signals from the UE. The serving network node or the radio network controller comprises a processor and a memory. The memory contains instructions executable by said processor, whereby the serving network node or the RNC is operative for sending, to the non-serving network node, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a HS-DPCCH, and receiving, from the non-serving network node, the information representing the HS-DPCCH, which information has been obtained by the non-serving network node by receiver processing the received uplink signal based on the received information enabling receiver processing.

[00014] According to other aspects, computer programs and carriers are also provided, the details of which will be described in the claims and the detailed description.

[00015] The above method and apparatus may be configured and implemented according to different optional embodiments. Further possible features and benefits of this solution will become apparent from the detailed description below.

Brief description of drawings

[00016] The solution will now be described in more detail by means of exemplary embodiments and with reference to the accompanying drawings, in which:

[0001 ] Fig. 1 a is a schematic view from above of a part of a wireless

communication network in which the present invention may be used.

[0002] Fig. 1 b is a schematic side view of the wireless communication network of fig. 1 a.

P43302 [0003] Fig. 2a is a schematic view from above of a part of a wireless

heterogeneous communication network in which the present invention may be used.

[0004] Fig. 2b is a schematic side view of the wireless communication network of fig. 2a.

[0005] Figs. 3-4 are flow charts of different embodiments of the invention.

[0006] Fig. 5 is a schematic block diagram of a wireless communication network.

[0007] Figs. 6-9 are schematic block diagrams of different embodiments of the invention.

Description of embodiments

[0008] One solution aiming at reducing the impact of the above described imbalance problems, which solution is up for discussion in 3GPP at the moment is a so-called Enhanced Dedicated Channel, E-DCH, decoupling operation, where the downlink and uplink serving network nodes are separated. The intention is to keep the LPN as the uplink serving network node at the same time as the HPN is the downlink serving network node for users in the imbalance region. This provides an uplink performance gain attributed to HPN offloading and because the LPN rise over thermal (RoT) headroom can be utilized more efficiently than the Macro headroom due to lower required uplink transmission power. The baseline E- DCH decoupling operation means that the LPN serves as the uplink serving network node and thereby issues E-DCH Absolute Grant Channel, E-AGCH.

However, the problem of reliably receiving downlink related control information communicated uplink from the UE still remains.

[0009] One possible concept to imbalance problems which the inventors have developed in this solution is to try using the best link at all times, and then forward received information to the relevant node(s). In other words, if the UL reception in the imbalance region is better in at least one of the non-serving nodes compared P43302 to the serving cell, let us receive the UL information in at least one of these non- serving nodes and let at least one of these non-serving nodes pass on to the serving node the information destined to the serving node. However, when it comes to HS-DPCCH signals, non-serving network nodes cannot process such signals in its receiver, and consequently cannot receive the HS-DPCCH signals, because they do not even know what kind of signal they are receiving.

Consequently, the present invention aims at making it possible for anon-serving network node to process such signals in its receiver. This may be possible according to the invention by the serving network node or the RNC sending information enabling receiver processing of a signal comprising a HS-DPCCH dedicated for a UE served by the serving network node to the non-serving network node.

[00010] The serving network node or the RNC may send semi-static and dynamic information to the non-serving network node as soon as a network node becomes a non-serving network node to a UE. Semi-static information does not need to be update but dynamic information may need to be updated, i.e. sent from the serving network node or the RNC to the non-serving network node, as soon as the dynamic information is changed. The RNC has control of when a network node it controls becomes a non-serving network node. In the cases when the serving network node is to communicate the information enabling receiver processing of a HS-DPCCH signal to the non-serving network node, the RNC informs the serving network node that the non-serving network node has become non-serving to a UE that the serving network node is serving network node for. In response to receiving this information from the RNC, the serving network node then sends the

information enabling receiver processing of a HS-DPCCH signal to the non- serving network node.

[0001 1 ] According to an embodiment of the invention, as shown in fig. 3 in connection with fig. 5, a method is provided performed by a non-serving network node 101 of a wireless communication network 100 for handling uplink signals sent by a UE 1 10. The wireless communication network further comprises a

P43302 serving network node 102 responsible for transmitting downlink signals to the UE 1 10. The non-serving network node 101 is capable of receiving uplink signals sent by the UE 1 10. The method performed by the non-serving network node comprises receiving 202, from the serving network node or from a RNC 120 to which the non-serving network node is connected, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a HS-DPCCH dedicated for the UE. The method further comprises receiving 204 the uplink signal from the UE, receiver processing 206 the received uplink signal based on the received information enabling receiver processing to obtain the information representing the HS-DPCCH, and sending 208 the obtained information representing the HS- DPCCH to the serving network node or the RNC.

[00012] A network node may be a physically separate base station, e.g. a node B, but also a logical node working either as a non-serving network node or a serving network node. For example, a physical base station may comprise both a serving node and a non-serving node. This may be the case when the physical base station serves many sector cells, and wherein one part of the physical base station serving a first sector cell would work as a serving network node for a UE and another part of the physical base station serving a second sector cell works as a non-serving network node for the same UE. The network node may also be called a cell in the disclosure. A serving network node serves a UE with

connection to the wireless network. In particular, the serving network node is in control of the connection of the UE to the network, e.g. it schedules the UE in downlink. In a similar manner, a non-serving network node may also provide the UE with connection to the network, e.g. in soft handover, but in contrast to the serving network node, the non-serving network node is not in control of the connection of the UE to the network. Transmitter processed information may signify encoded and/or spread information. Receiver processing of the received uplink signal may signify to de-spread and/or to decode the received signal, or more specifically, to de-spread and/or decode the transmitter processed information of the received signal. The decoding may be either partial or full P43302 decoding. To de-spread the received signal may signify to demodulate the received signal.

[00013] By the described method in a non-serving network node it is facilitated that an uplink signal comprising transmitter processed information representing a HS-DPCCH for the UE can be receiver processed by the non-serving network node, e.g. be de-spread and possibly also decoded by the non-serving network node, and then sent further to the serving network node or the RNC as de-spread and possibly also decoded information. When the information has not been decoded or only partial decoding has been performed by the non-serving network node, the full decoding will be performed by the serving network node. This method is especially advantageous when the serving network node receives weaker signals from the UE than the non-serving network node. This may be the case in e.g. soft handover cases in a heterogeneous network where the serving network node is a high power node that sends stronger signals to the UE than the non-serving network node which for example is a low power node. In such cases, the signals from the serving network node may be received at a higher signals strength than the signals from the non-serving network node even though the low power node is closer (in terms of radio propagation conditions) to the UE than the high power node.

[00014] According to an embodiment, the information enabling receiver processing comprises semi-static information such as one or more of the following: Channel Quality Indicator (CQI) feedback cycle, CQI repetition factor, ACK-NACK repetition factor, CQI power offsets, HS-DPCCH slot format and HS-DPCCH coding format.

[00015] Semi-static information signifies that the information is configured at setup of a new UE connection, for example via Radio Resource Control, RRC, and/or Node B Application Part, NBAP. After the information has been configured it is updated on a slow basis, potentially once or never. Semi-static information is conveyed via L2/L3 signaling, e.g. RRC and /or NBAP, compared to dynamic information that relies on "fast" L1 signaling, e.g. HS-SCCH orders. Semi-static P43302 information can be changed e.g. via reconfiguration messages. Current receiver structure assumes that this semi-static information is available. If not, the receiver cannot fully process the received signal. Hence, it is of interest for the non-serving network node to receive such semi-static information from the serving node or the RNC for receiver processing the received signal.

[00016] In case multiple antennas are used at both receiver and transmitter, so called Multiple Input Multiple Output, MIMO, the information enabling receiver processing may also comprise MIMO information such as MIMO configuration (RRC/NBAP signaling), which is semi-static information and/or number of scheduled streams, which is dynamic information.

[00017] According to an embodiment, the information enabling receiver processing comprises dynamic information such as number of secondary cells active and identity of active carriers.

[00018] Number of secondary cells active (e.g. secondary serving HS-DSCH cells active) signifies number of additional downlink carriers that are enabled. By sending this information from the serving network node to the non-serving network node, receiver processing of the received signal is enabled, or at least facilitated. If not known, the non-serving network node may need to assume that all the UE's secondary cells are active, which has a negative impact on the performance..

[00019] According to another embodiment, the wireless communication network is a heterogeneous network, the serving network node 102 is a high power node and the non-serving network node 101 is a low power node transmitting wireless signals with a lower power than the high power node.

[00020] Fig. 4 illustrates an embodiment of the invention performed by a serving network node 102 or an RNC 120 of a wireless communication network 100 for handling uplink signals sent by a UE 1 10. The serving network node 102 is responsible for transmitting downlink signals to the UE 1 10. The wireless communication network further comprises a non-serving network node 101

P43302 capable of receiving uplink signals from the UE 1 10. The method comprises sending 302, to the non-serving network node, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH, and receiving 304, from the non-serving network node, the information representing the HS- DPCCH, which information has been obtained by the non-serving network node by receiver processing the received uplink signal based on the received information enabling receiver processing. By the serving network node sending such information enabling receiver processing of a signal comprising HS-DPCCH information to the non-serving network node, the non-serving network node, which may have a better reception of the HS-DPCCH signal than the serving network node, can receiver process the transmitter processed HS-DPCCH signal and send the receiver processed HS-DPCCH signal to the serving network node. Thereby, the serving network node can receive the HS-DPCCH signal via the non-serving network node even in the cases when the HS-DPCCH signal from the UE does not reach the serving network node directly from the UE.

[00021 ] According to an embodiment, the non-serving network node 101 is a plurality of network nodes in an active set of the UE, and the information enabling receiver processing is sent 302 to the plurality of network nodes. The active set of the UE comprises network nodes that are in communication with the UE, e.g. in soft handover. In other words, in this embodiment the serving network node sends the information enabling receiver processing not just to one non-serving network node but to a plurality of non-serving network nodes that are in the active set of the UE. After having received the information enabling receiver processing, the plurality of network nodes may all try to receiver process the signal and to send the obtained receiver processed information to the serving network node. The serving network node may then select what information from which of the plurality of network nodes to use. The plurality of network nodes may be all network nodes in the active set or a subset of the network nodes in the active set.

P43302 [00022] According to another embodiment, wherein the non-serving network node is a subset of network nodes in an active set of the UE, the method further comprises determining 301 to send the information enabling receiver processing to the subset of network nodes, based on determining criteria such as position information for the serving network node in relation to positioning information for individual of the network nodes in the active set, transmit power of the individual of the network nodes in the active set or received UL SIR quality for the individual of the network nodes in the active set. Thereafter, the information enabling receiver processing is sent 302 to the subset of network nodes based on the determination. By such a method the serving network node, or the RNC, may decide based on the determination criteria which of the plurality of network nodes in the active set that are to be able to receiver process the HS-DPCCH data and send it further to the serving network node.

[00023] As mentioned, today it is not always possible to decode the HS-DPCCH in a non-serving network node (at least when the non-serving network node is located in a different Node B compared to the serving network node) since the necessary receiver parameters are not available in the non-serving network node. A non-serving network node needs to know all, or a subset, of the following RNC configured parameters in order to be able to decode HS-DPCCH:

- CQI feedback cycle - This parameter determines how frequent CQIs are transmitted and is needed in order for the network to know when to expect a CQI;

- CQI repetition factor- This parameter contains the number of

consecutive subframes used for a single CQI message.

- ACK-NACK repetition factor- This parameter contains the number of consecutive subframes used for a single hybrid-ARQ message.

- CQI power offsets (CQI/ACK/NACK) - These parameters are used to determine the power offset for the hybrid-ARQ and CQI fields on the HS-DPCCH. The power offsets can be different for ACKs, NACKs and CQIs.

P43302 - The HS-DPCCH slot format - The slot format indicates the spreading factor used for HS-DPCCH and is therefore required to be able to detect and decode the HS-DPCCH.

- The HS-DPCCH coding format - This information is needed in

order to know how to decode the HS-DPCCH, and includes the number of code words and the code words themselves. The coding format will be different depending on, for example, multicarrier related configurations such as whether MIMO is enabled, the number of secondary cell enabled and secondary cell active, and multi-flow configurations.

- The above mentioned parameters may be signaled via NBAP/RRC.

[00024] The current receiver structure in the network nodes assumes that these parameters are available. Hence, according to an embodiment, all or at least a subset of these parameters are sent to the non-serving cell in order to decode the HS-DPCCH.

[00025] The parameters discussed above, except secondary cell active, are configured via RRC and NBAP and are therefore semi-static. A second problem with decoding the HS-DPCCH is that in some configurations, it is assumed that the receiver knows instantaneous scheduling decisions, i.e. dynamic scheduling, layer-1 , information. Downlink multicarrier operation is one example that in some cases requires this dynamic information exchange between the transmitter and the receiver. If the receiver is located in a non-serving network node, this means that the serving network node needs to inform the non-serving network node about this dynamic information.

[00026] The setup for multicarrier operation is as follows. The serving network node is always enabled and activated. In addition, one or several secondary serving network nodes (the nodes may hereinafter also be called "cells") can be enabled. In the 3GPP specifications, the parameter Secondary_Cell_Enabled is used to describe the number of additionally configured cells. The number of P43302 enabled secondary serving cells is controlled via RRC signaling. In addition, a parameter Secondary_Cell_Active is used to describe how many of the enabled secondary serving cells that is currently active. Shared Control Channel for High Speed Downlink Shared Channel, HS-SCCH, orders can be used to activate or deactivate secondary serving cells. Finally, it should be noticed that the scheduler can decide to not schedule any data on the serving cell or one or several of the active secondary serving cells even though they are active.

[00027] Since activation of secondary cells is done via HS-SCCH orders, the number of active secondary cells is not immediately known by non-serving cells. Hence, this information needs to be sent by the serving cell to the non-serving cell. Alternatively, the non-serving cell needs to assume the worst case all the time, i.e. that all secondary cells are active. However, this assumption will have a negative effect on the performance. With less activate carriers the decoding space can be limited and thereby enhancing the detection and decoding performance since e.g. the number of Hypotheses is reduced and the minimum Hamming distance is increased. Next, two design choices for multicarrier are illustrated that was adopted in order to significantly improve the performance, but that relies on that the receiver and transmitter can share instantaneous scheduling information.

[00028] Consider the 3GPP release 9 dual-cell HSDPA with MIMO. The hybrid- ARQ Acknowledgement/Non-acknowledgement, ACK/NACK, codebook for this scenario uses the same code word to represent different hybrid-ARQ ACK/NACK messages. For example, the code words representing A N, which denotes single stream scheduled on both carriers, primary carrier ACK and secondary carrier NACK, and A/NA, which denotes single stream on primary carrier and dual stream on secondary carrier with ACK for primary carrier and NACK and ACK for the two transport blocks on the secondary carrier, are identical. This essentially means that the receiver needs to take into account the number of transport blocks scheduled on each carrier in the decoding process. Alternatively, the receiver needs to include all non-identical codewords in the decoder process and let the serving cell re-interpret the ACK/NACK message for a duplicate codeword

P43302 depending on what was actually scheduled. Another problem is that the decoding performance becomes much worse if all non-identical codewords are included and not only the relevant ones, i.e. for efficient operation the receiver adapts to the number of scheduled transport blocks on each carrier.

[00029] Consider the 3GPP release 10, which uses an HS-DPCCH slot format based on spreading factor SF128. In this case, the handling of ACK/NACK and CQI depends on the number of active secondary carriers. More specifically, whenever one or several secondary serving cells are deactivated, repetition in different forms is employed. To make full use of this, the non-serving cell needs to know what carriers are active. Considerable performance degradation occurs if this information is not available in the non-serving cell(s).

[00030] The methodology described above, i.e. to enable that any node in the active set can receive and decode data and thereafter forward it to the appropriate node, are applicable in many scenarios. The discussion is focused on

heterogeneous network deployments but is equally applicable to homogeneous network deployments, i.e. deployments with nodes of same/similar type. Another scenario where the methodology is also useful is for multi-flow configurations, where the HS-DPCCH needs to be received in more than one cell, i.e. two cells belonging to the same or different NodeBs can be simultaneously configured as serving HS-DSCH cells. In this case, the link towards one of the serving cells will inevitably be worse than the other, especially in heterogeneous network

deployments. Hence, it can be useful to be able to decode all the HS-DPCCH information in one of the cells, e.g. one of the serving cells, or the cell in the active set with the best uplink, and then forward the information to the appropriate nodes. In order to do this, the decoding cell needs all essential information from the scheduling cell(s).

[00031 ] The discussion above focuses on detecting and decoding the HS- DPCCH in the cell in the active set with the best uplink. In practice, however, it can be difficult to ensure that the best cell is utilized at all times. Hence, different alternatives are described below for how to determine which cell(s) that should do P43302 the decoding and therefore needs configuration infornnation and instantaneous scheduling infornnation. According to a first alternative, all or a subset of all non- serving cells are seen as potential candidates for handling the decoding. Hence, the all or a subset of all non-serving cells receive the detection and decoding infornnation from relevant nodes, i.e. serving cell and/or RNC. The all or a subset of all non-serving cells then try to decode and forward the information to the serving cell, e.g. the serving HS-DSCH cell. The serving cell will then chose what information to use, or even combine the information from several non-serving cells into single information elements. Whenever more than one link is in the active set, the network decides which non-serving cell should detect and decode HS-DPCCH. This can be based on, for example, location knowledge, e.g. GPS, knowledge of the transmit power, e.g. CPICH power, of the cells in the active set or knowledge of the received UL SIR quality in the cells in the active set. Relevant information is then sent to the non-serving cell that was decided to detect and decode HS- DPCCH.

[00032] The information to be communicated from the RNC 120 or the serving cell 102 to the non-serving cell(s) 101 may be communicated over different interfaces, examples of which are shown in fig. 5. According to a first embodiment, the information may be communicated over the lub interface between each of the network nodes 101 , 102 and the RNC 120, for example using proprietary signaling over NBAP at radio link, RL, Setup, RL Addition and RL Reconfiguration.

Alternatively, new or modified lub information elements are added to the standard, or existing functionality is changed such that the information becomes known in the non-serving cells as well. This is mainly applicable to semi-static information. According to a second embodiment, the information from the serving cell 102 to the non-serving cell(s) 101 is forwarded over a link between the serving cell and the non-serving cell(s). The link can be direct via a proprietary, or even

standardized interface, e.g. lubx, or indirect via the RNC 120.

[00033] For efficient operation, the delay between the nodes should be

sufficiently small. Also, when forwarding the information required for detection and

P43302 decoding, additional infornnation such as identities (ID), e.g. UE ID, network node ID or cell ID, and timing info, e.g. time-stamp or Current Frame Number, CFN, and Current Slot Number, CSN, can be included to help the process. To reduce the signaling between nodes, the information can potentially be bundled. For example, every cell can bundle information from all radio links, RL, or radio link sets, RLS, received the latest x ms, where x is configurable. Setting x is then a compromise of signal intensity and delay. Note that having a large x might work better for some information than for other, e.g. ACK/NACK is typically more time-critical than CQI values.

[00034] Fig. 6 describes an embodiment of a non-serving network node 101 of a wireless communication network, operable for handling uplink signals sent by a UE, wherein the wireless communication network further comprises a serving network node responsible for transmitting downlink signals to the UE. The non- serving network node 101 is capable of receiving uplink signals sent by the UE. The non-serving network node 101 comprising a processor 603 and a memory 604, said memory containing instructions executable by said processor, whereby the non-serving network node 101 is operative for receiving, from the serving network node or from an RNC to which the non-serving network node is

connected, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH. The non-serving network node 101 is further operative for receiving the uplink signal from the UE, receiver processing the received uplink signal based on the received information enabling receiver processing to obtain the information representing the HS-DPCCH, and sending the obtained information representing the HS-DPCCH to the serving network node or the RNC.

[00035] According to an embodiment of the non-serving network node, the information enabling receiver processing comprises semi-static information such as one or more of the following: Channel Quality Indicator (CQI) feedback cycle, CQI repetition factor, ACK-NACK repetition factor, CQI power offsets, HS-DPCCH

P43302 slot format and HS-DPCCH coding format. According to another embodiment, the information enabling receiver processing comprises dynamic information such as number of secondary cells active and/or identity of active carriers.

[00036] The non-serving network node may further comprise a communication unit 602, which may be considered to comprise conventional means for

communicating from and/or to the other nodes in the network, such as the UE, the serving network node and the RNC. The conventional communication means may include at least one transmitter and at least one receiver. The non-serving network node may further comprise one or more storage units 606 and further functionality 607 useful for the non-serving network node to serve its purpose as non-serving network node, e.g. base station. The instructions executable by said processor may be arranged as a computer program 605 stored in said memory 604. The processor 603 and the memory 604 may be arranged in an arrangement 601 . The arrangement 601 may be a micro processor and adequate software and storage therefore, a Programmable Logic Device, PLD, or other electronic

component(s)/processing circuit(s) configured to perform the actions, or methods mentioned above.

[00037] The computer program 605 may comprise computer readable code means, which when run in the non-serving network node causes the non-serving network node to perform the steps described in any of the described

embodiments. The computer program may be carried by a computer program product connectable to the processor. The computer program product may be the memory 604. The memory 604 may be realized as for example a RAM (Random- access memory), ROM (Read-Only Memory) or an EEPROM (Electrical Erasable Programmable ROM). Further, the computer program may be carried by a separate computer-readable medium, such as a CD, DVD or flash memory, from which the program could be downloaded into the memory 604. Alternatively, the computer program may be stored on a server or any other entity connected to the communication network to which the system of network nodes has access via its

P43302 communication unit 602. The computer program may then be downloaded from the server into the memory 604.

[00038] Fig. 7 describes another embodiment of a non-serving network node 101 of a wireless communication network, operable for handling uplink signals sent by a UE, wherein the wireless communication network further comprises a serving network node responsible for transmitting downlink signals to the UE. The non- serving network node 101 is capable of receiving uplink signals sent by the UE. The non-serving network node 101 comprises a first receiving module 702 for receiving, from the serving network node or from an RNC to which the non-serving network node is connected, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH. The non-serving network node 101 further comprises a second receiving module 704 receiving the uplink signal from the UE, a processing module 706 for receiver processing the received uplink signal based on the received information enabling receiver processing to obtain the information representing the HS-DPCCH, and a sending module 708 for sending the obtained information representing the HS-DPCCH to the serving network node or the RNC.

[00039] Fig. 8 describes an embodiment of a serving network node 102 or an RNC 120 connected to the serving network node, of a wireless communication network, operable for handling uplink signals sent by a UE, wherein the serving network node 102 is responsible for transmitting downlink signals to the UE, and wherein the wireless communication network further comprises a non-serving network node capable of receiving uplink signals from the UE. The serving network node 102 or the RNC 120 comprises a processor 803 and a memory 804, said memory containing instructions executable by said processor, whereby the serving network node 102 or the RNC is operative for sending, to the non-serving network node, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information

representing a Dedicated Physical Control Channel for High Speed Downlink

P43302 Shared Channel, HS-DPCCH, and receiving, from the non-serving network node, the information representing the HS-DPCCH, which information has been obtained by the non-serving network node by receiver processing the received uplink signal based on the received information enabling receiver processing. If the RNC receives the information from the non-serving network node, the RNC is further operative for sending the information representing the HS-DPCCH that it has received from the non-serving network node to the serving network node, using e.g. standardized or proprietary lub/NBAP information elements.

[00040] According to an embodiment of the serving network node 102 or the RNC 120, the information enabling receiver processing comprises semi-static information such as one or more of the following: Channel Quality Indicator (CQI) feedback cycle, CQI repetition factor, ACK-NACK repetition factor, CQI power offsets, HS-DPCCH slot format and HS-DPCCH coding format. According to another embodiment, the information enabling receiver processing comprises dynamic information such as number of secondary cells active and/or identity of active carriers.

[00041 ] According to another embodiment, the non-serving network node is a plurality of network nodes in an active set of the UE, and the serving network node 102 or the radio network controller 120 is arranged to send the information enabling receiver processing to the plurality of network nodes.

[00042] According to another embodiment, the non-serving network node is a subset of network nodes in an active set of the UE, and the memory 804 further contains instructions executable by said processor 803, whereby the serving network node 102 or the radio network controller is 120 operative for determining to send the information enabling receiver processing to the subset of network nodes, based on determining criteria such as position information for the serving network node in relation to positioning information for individual of the network nodes in the active set, transmit power of the individual of the network nodes in the active set or received UL SIR quality for the individual of the network nodes in the

P43302 active set, and wherein the information enabling receiver processing is sent to the subset of network nodes based on the determination.

[00043] The serving network node 102 or the RNC 120 may further comprise a communication unit 802, which may be considered to comprise conventional means for communicating from and/or to the other nodes in the network, such as the UE and the non-serving network node, and, in the alternative of a serving network node, the RNC and in the alternative of an RNC, the serving network node. The conventional communication means may include at least one transmitter and at least one receiver. The serving network node 120 or RNC 120 may further comprise one or more storage units 806 and further functionality 807 useful for the serving network node to serve its purpose as serving network node, e.g. base station, such as a scheduler, or the RNC to serve its purpose as RNC. The instructions executable by said processor may be arranged as a computer program 805 stored in said memory 804. The processor 803 and the memory 804 may be arranged in an arrangement 801 . The arrangement 801 may be a micro processor and adequate software and storage therefore, a Programmable Logic Device, PLD, or other electronic component(s)/processing circuit(s) configured to perform the actions, or methods mentioned above.

[00044] The computer program 805 may comprise computer readable code means, which when run in the serving network node causes the serving network node to perform the steps described in any of the described embodiments, or when run in the RNC causes the RNC to perform the steps described in any of the described embodiments. The computer program may be carried by a computer program product connectable to the processor. The computer program product may be the memory 804. The memory 804 may be realized as for example a RAM (Random-access memory), ROM (Read-Only Memory) or an EEPROM (Electrical Erasable Programmable ROM). Further, the computer program may be carried by a separate computer-readable medium, such as a CD, DVD or flash memory, from which the program could be downloaded into the memory 804. Alternatively, the computer program may be stored on a server or any other entity connected to the

P43302 communication network to which the serving network node and/or the RNC has access via its communication unit 802. The computer program may then be downloaded from the server into the memory 804.

[00045] Fig. 9 describes another embodiment of a serving network node 102 or a radio network controller 120 connected to the serving network node, of a wireless communication network, operable for handling uplink signals sent by a UE. The serving network node 102 is responsible for transmitting downlink signals to the UE, and the wireless communication network further comprises a non-serving network node capable of receiving uplink signals from the UE. The serving network node 102 or the radio network controller 120 comprises a sending module 902 for sending to the non-serving network node, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH, and a receiving module 904 for receiving, from the non-serving network node, the information representing the HS-DPCCH, which information has been obtained by the non- serving network node by receiver processing the received uplink signal based on the received information enabling receiver processing.

[00046] Although the description above contains a plurality of specificities, these should not be construed as limiting the scope of the concept described herein but as merely providing illustrations of some exemplifying embodiments of the described concept. It will be appreciated that the scope of the presently described concept fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the presently described concept is accordingly not to be limited. Reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more." All structural and functional equivalents to the elements of the above- described embodiments that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed hereby. Moreover, it is not necessary for an apparatus or method to address each

P43302 and every problem sought to be solved by the presently described concept, for it to be encompassed hereby.

P43302

Claims

1 . A method performed by a non-serving network node (101 ) of a wireless communication network (100) for handling uplink signals sent by a user

equipment, UE, (1 10) wherein the wireless communication network further comprises a serving network node (102) responsible for transmitting downlink signals to the UE (1 10), and wherein the non-serving network node (101 ) is capable of receiving uplink signals sent by the UE (1 10), the method comprising:

receiving (202), from the serving network node or from a radio network controller, RNC (120), to which the non-serving network node is connected, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a

Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH, dedicated for the UE,

receiving (204) the uplink signal from the UE,

receiver processing (206) the received uplink signal based on the received information enabling receiver processing to obtain the information representing the HS-DPCCH,

sending (208) the obtained information representing the HS-DPCCH to the serving network node or the RNC.

2. Method according to claim 1 , wherein the information enabling receiver processing comprises semi-static information such as one or more of the following: Channel Quality Indicator (CQI) feedback cycle, CQI repetition factor, ACK-NACK repetition factor, CQI power offsets, HS-DPCCH slot format and HS-DPCCH coding format.

3. Method according to claim 1 or 2, wherein the information enabling receiver processing comprises dynamic information such as number of secondary cells active and/or identity of active carriers.

P43302

4. Method according to any of the preceding claims, wherein the wireless communication network is a heterogeneous network, the serving network node (102) is a high power node and the non-serving network node (101 ) is a low power node transmitting wireless signals with a lower power than the high power node.

5. A method performed by a serving network node (102) or a radio network controller (120) of a wireless communication network (100) for handling uplink signals sent by a user equipment, UE (1 10), wherein the serving network node (102) is responsible for transmitting downlink signals to the UE (1 10), and wherein the wireless communication network further comprises a non-serving network node (101 ) capable of receiving uplink signals from the UE (1 10), the method comprising:

sending (302), to the non-serving network node, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal

comprising transmitter processed information representing a Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH, and

receiving (304), from the non-serving network node, the information representing the HS-DPCCH, which information has been obtained by the non- serving network node by receiver processing the received uplink signal based on the received information enabling receiver processing.

6. Method according to claim 5, wherein the information enabling receiver processing comprises semi-static information such as one or more of the following: Channel Quality Indicator (CQI) feedback cycle, CQI repetition factor, ACK-NACK repetition factor, CQI power offsets, HS-DPCCH slot format and HS-DPCCH coding format.

7. Method according to claim 5 or 6, wherein the information enabling receiver processing comprises dynamic information such as number of secondary cells active and/or identity of active carriers.

8. Method according to any of claims 5-7, wherein the wireless

communication network is a heterogeneous network, the serving network node

P43302 (102) is a high power node and the non-serving network node (101 ) is a low power node transmitting wireless signals with a lower power than the high power node.

9. Method according to any of claims 5-8, wherein the non-serving network node is a plurality of network nodes in an active set of the UE, and wherein the information enabling receiver processing is sent (302) to the plurality of network nodes.

10. Method according to any of claims 5-9, wherein the non-serving network node is a subset of network nodes in an active set of the UE, the method further comprising:

determining (301 ) to send the information enabling receiver processing to the subset of network nodes, based on determining criteria such as position information for the serving network node in relation to positioning information for individual of the network nodes in the active set, transmit power of the individual of the network nodes in the active set or received UL SIR quality for the individual of the network nodes in the active set, and

wherein the information enabling receiver processing is sent (302) to the subset of network nodes based on the determination.

1 1 . A non-serving network node (101 ) of a wireless communication network (100), operable for handling uplink signals sent by a user equipment, UE, (1 10) wherein the wireless communication network further comprises a serving network node (102) responsible for transmitting downlink signals to the UE (1 10), and wherein the non-serving network node (101 ) is capable of receiving uplink signals sent by the UE (1 10), the non-serving network node comprising a processor (603) and a memory (604), said memory containing instructions executable by said processor, whereby the non-serving network node (101 ) is operative for:

receiving, from the serving network node (102) or from a radio network controller, RNC (120), to which the non-serving network node is connected, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a

P43302 Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH,

receiving the uplink signal from the UE,

receiver processing the received uplink signal based on the received information enabling receiver processing to obtain the information representing the HS-DPCCH,

sending the obtained information representing the HS-DPCCH to the serving network node or the RNC.

12. Non-serving network node (101 ) according to claim 1 1 , wherein the information enabling receiver processing comprises semi-static information such as one or more of the following: Channel Quality Indicator (CQI) feedback cycle, CQI repetition factor, ACK-NACK repetition factor, CQI power offsets, HS-DPCCH slot format and HS-DPCCH coding format.

13. Non-serving network node (101 ) according to claim 1 1 or 12, wherein the information enabling receiver processing comprises dynamic information such as number of secondary cells active and/or identity of active carriers.

14. A serving network node (102) or a radio network controller (120) connected to the serving network node, of a wireless communication network (100), operable for handling uplink signals sent by a user equipment, UE (1 10), wherein the serving network node (102) is responsible for transmitting downlink signals to the UE (1 10), and wherein the wireless communication network further comprises a non-serving network node (101 ) capable of receiving uplink signals from the UE (1 10), the serving network node (102) or the radio network controller (120) comprising a processor (803) and a memory (804), said memory containing instructions executable by said processor, whereby the serving network node (102) or the radio network controller is operative for:

sending, to the non-serving network node, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a Dedicated Physical

Control Channel for High Speed Downlink Shared Channel, HS-DPCCH, and P43302 receiving, from the non-serving network node, the information representing the HS-DPCCH, which information has been obtained by the non- serving network node by receiver processing the received uplink signal based on the received information enabling receiver processing.

15. Serving network node (102) or radio network controller (120) according to claim 14, wherein the information enabling receiver processing comprises semi- static information such as one or more of the following: Channel Quality Indicator (CQI) feedback cycle, CQI repetition factor, ACK-NACK repetition factor, CQI power offsets, HS-DPCCH slot format and HS-DPCCH coding format.

16. Serving network node (102) or radio network controller (120) according to claim 14 or 15, wherein the information enabling receiver processing comprises dynamic information such as number of secondary cells active and/or identity of active carriers.

17. Serving network node (102) or radio network controller (120) according to any of claims 14-16, wherein the non-serving network node is a plurality of network nodes in an active set of the UE, and wherein serving network node or the radio network controller is arranged to send the information enabling receiver processing to the plurality of network nodes.

18. Serving network node (102) or radio network controller (120) according to any of claims 14-17, wherein the non-serving network node is a subset of network nodes in an active set of the UE, wherein said memory (804) further contains instructions executable by said processor (803), whereby the serving network node (102) or the radio network controller is (120) operative for:

determining to send the information enabling receiver processing to the subset of network nodes, based on determining criteria such as position information for the serving network node in relation to positioning information for individual of the network nodes in the active set, transmit power of the individual of the network nodes in the active set or received UL SIR quality for the individual of the network nodes in the active set, and wherein the infornnation enabling receiver processing is sent to the subset of network nodes based on the determination.

19. A computer program (605) comprising computer readable code means, which, when run in a non-serving network node (101 ) operable in a wireless communication network (100) further comprising a serving network node (102) responsible for transmitting downlink signals to the UE (1 10), and wherein the non-serving network node (101 ) is capable of receiving uplink signals sent by the UE (1 10), causes the non-serving network node to perform the following steps:

receiving, from the serving network node (102) or from a radio network controller, RNC (120), to which the non-serving network node is

connected, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH,

receiver processing the uplink signal when received, based on the received information enabling receiver processing to obtain the information representing the HS-DPCCH,

20. A carrier containing the computer program (605) according to claim 19, wherein the carrier is one of an electronic signal, optical signal, radio signal or computer readable storage medium.

21 . A computer program (805) comprising computer readable code means, which, when run in a serving network node (102) or a radio network controller (120) connected to the serving network node, of a wireless communication network (100), operable for communicating uplink signals sent by a user equipment, UE (1 10), wherein the serving network node (102) is responsible for transmitting downlink signals to the UE (1 10), and wherein the wireless

communication network further comprises a non-serving network node (101 ) capable of receiving uplink signals from the UE (1 10), causes the serving network node (102) or the radio network controller (120), to perform the following steps:

sending, to the non-serving network node, information enabling receiver processing of an uplink signal sent by the UE, the uplink signal comprising transmitter processed information representing a Dedicated Physical Control Channel for High Speed Downlink Shared Channel, HS-DPCCH, , and receiving, from the non-serving network node, the information representing the HS-DPCCH, which information has been obtained by the non- serving network node by receiver processing the received uplink signal based on the received information enabling receiver processing.

22. A carrier containing the computer program (805) according to claim 21 , wherein the carrier is one of an electronic signal, optical signal, radio signal or computer readable storage medium.