Technical field

[0001 ] The present disclosure relates to wireless communication and in particular to selection of a control information reporting state of the wireless device.

Background

[0002] In a wireless communication network, wireless devices generally move about within a coverage area of the wireless communication network. Some non- limiting examples of a wireless device are a User equipment, UE, a Personal Digital Assistant, PDA, a laptop, or any other apparatus such as e.g. a vehicle comprising communication means for communicating with a node or entity of the wireless communication network.

[0003] As the wireless device move about, it may occasionally find itself having poor radio coverage and/or channel quality and at other times and/or locations having good radio coverage and/or channel quality. Depending on the conditions of e.g. the channel quality, a network node and the wireless device may take different actions with regards to the communication between them.

[0004] In order to estimate the channel quality, a wireless device may measure e.g. downlink received power, with regards to a received reference symbol transmitted from a network node and/or with regards to a received data signal. Similarly, the network node may measure e.g. uplink received power with regards to transmitted data signal from the wireless device and/or with regards to a reference signal transmitted by the wireless device.

[0005] The wireless device may measure the quality of the downlink channel and then report the measured downlink channel quality to the network node. One example for a parameter that the wireless device may use to report a measured downlink channel quality is the Channel Quality Indicator, CQI. The CQI is transmitted in the 2 ^nd and 3 ^rd slots of the High Speed-Dedicated Physical Control Channel, HS-DPCCH, is an indicator for High Speed Downlink Packet Data Access, HSDPA, down-link channel quality and its frequent reporting is essential to maintain a good downlink throughput. The CQI is signalled from the wireless device, e.g. a UE, to the network node, e.g. a Node B, NB, on one or several uplink HS-DPCCH physical channels, together with other channel state

information, depending on configured downlink transmission mode.

[0006] Figure 1a is a flowchart of a data call set-up procedure. Figure 1 a shows the messages exchanged between the NB and the UE during typical data call set up. From the common pilot channels (primary and secondary common pilot channels, P-CPICH and S-CPICHs), the UE estimates the channel and computes the channel quality information and precoding channel indicator. This information along with Hybrid Automatic Repeat request, hybrid ARQ

acknowledgement/negative acknowledgement, ACK/NACK, is reported to NB using High Speed Dedicated Physical Control Channel, HS-DPCCH. The structure of HS-DPCCH for a single carrier is shown in figure 1 b when the UE is configured in non - Multiple Input Multiple Output, MIMO, mode.

[0007] Figure 1c shows HS-DPCCH structure when the UE is configured in MIMO mode with 2 Transmit antennas, the CQI is computed as

^ jl 5 x CQI _t + CQI ₂ + 31 when 2 transport blocks are preferred by the UE

[ CQI _S when 1 transport block is preferred by the UE

Where CQI is the channel quality per individual layer.

[0008] It can be observed from the above equation that if the CQI is less than 31 , the Rank information is 1 , otherwise Rank information is 2. Precoding Control Index, PCI, is the precoding information bits selected in the subset of the codebook corresponding to the rank information.

[0009] Figure 1d shows the HS-DPCCH structure when the UE is configured in MIMO mode with four transmit antennas. Where in addition to HAR-ACK, CQI, and PCI, a separate 2 bits are transmitted to indicate the number of transport blocks UE is preferring, Number of Transfer Blocks Preferred, NTBP. This is also called rank information, Rl.

[00010] Once the NB receives this information, it may allocate the required channelization codes, modulation and coding, precoding channel index to the UE after scheduling. This information is conveyed to the UE by a high speed shared control channel, HS-SCCH. Once the UE detects the HS-SCCH, downlink transmission may start through data traffic channel using Physical Downlink Shared Channel, HS-PDSCH.

[0001 1 ] In some cases, the UE may not be in a position to send a control information such as e.g. either HARQ-ACK or CQI or PMI (Precoding Matrix Indicator) or Rl. In these cases, configuring a fixed reporting period causes inefficient usage of power from the UE as most of the power will be used for sending CSI and HARQ-ACK. In these scenarios, it might lose connection with the Node B thereby impacting the coverage.

Summary

[00012] The object is to obviate at least some of the problems outlined above. In particular, it is an object to provide a wireless device and network node and respective methods thereby for selecting a control information reporting state of the wireless device, the control information reporting state relating to how to report at least one of channel state information, acknowledgement, ACK, and negative ACK, NACK.

[00013] According to an aspect a method performed by a wireless device for selecting a control information reporting state of the wireless device, the control information reporting state relating to how to report at least one of channel state information, ACK, and NACK is provided. The method comprises determining at least one characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node; and selecting a first or a second control information reporting state to use based on the determined at least one characteristic. [00014] According to an aspect, a method performed by a network node for transmitting downlink data transmissions to a wireless device, the wireless device employing at least two control information reporting states relating to how the wireless device reports at least one of channel state information, ACK, and NACK, for downlink transmissions from the network node. The method comprises receiving information from the wireless device that the wireless device has changed control information reporting state, wherein the at least two control information reporting states are a first control information reporting state and a second control information reporting state. When the change of control information reporting states is from the first to the second control information reporting state, the method comprises refraining from transmitting downlink data transmissions to the wireless device; and when the change of control information reporting states is from the second to the first control information reporting state transmitting downlink data transmissions to the wireless device.

[00015] According to an aspect, a wireless device for selecting a control information reporting state of the wireless device, the control information reporting state relating to how to report at least one of channel state information, ACK, and NACK is provided. The wireless device is configured to determine at least one characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node; and to select a first or a second control information reporting state to use based on the determined at least one

characteristic.

[00016] According to an aspect, a network node for transmitting downlink data transmissions to a wireless device, the wireless device employing at least two control information reporting states relating to how the wireless device reports at least one of channel state information, ACK, and NACK for downlink transmissions from the network node is provided. The network node is configured to receive information from the wireless device that the wireless device has changed control information reporting state, wherein the at least two control information reporting states are a first control information reporting state and a second control information reporting state. The network node is further configured to refrain from transmitting downlink data transmissions to the wireless device when the change of control information reporting states is from the first to the second control information reporting state; and when the change of control information reporting states is from the second to the first control information reporting state: the network node is configured to transmit downlink data transmissions to the wireless device.

[00017] An advantage of embodiments herein is that the signalling overhead of the HS-DPCCH is reduced and hence power may be saved, especially in situations where the ability of the wireless device to receive downlink

transmissions from the network node is impaired. The power that may be saved may be used for other data traffic or voice channels. Moreover, interference to other uplink transmitting wireless devices may be reduced.

Brief description of drawings

[00018] Embodiments will now be described in more detail in relation to the accompanying drawings, in which:

[00019] Figure 1 a is a signalling diagram illustrating messages exchanged between a Node B, NB, and a UE.

[00020] Figure 1 b is a block diagram of the HS-DPCCH structure when a wireless device, or UE, is configured in non-MIMO mode.

[00021 ] Figure 1 c is a block diagram of the HS-DPCCH structure when a wireless device, or UE, is configured in MIMO mode.

[00022] Figure 1 d is a block diagram of the HS-DPCCH slot format when the wireless device is configured in MIMO mode with four transmit antennas.

[00023] Figure 1 e is a flowchart of a method performed by a wireless device for selecting a control information reporting state of the wireless device, according to an exemplifying embodiment. [00024] Figure 1f is a flowchart of a method performed by a wireless device for selecting a control information reporting state of the wireless device, according to another exemplifying embodiment.

[00025] Figure 2 is a flowchart of a method performed by a network node for transmitting downlink data transmissions to a wireless device, according to an exemplifying embodiment.

[00026] Figure 3 is a block diagram of a wireless device for selecting a control information reporting state of the wireless device, according to an exemplifying embodiment.

[00027] Figure 4 is a block diagram of a network node for transmitting downlink data transmissions to a wireless device, according to an exemplifying

embodiment.

[00028] Figure 5 is a block diagram of a wireless device for selecting a control information reporting state of the wireless device, according to an exemplifying embodiment.

[00029] Figure 6 is a block diagram of a network node for transmitting downlink data transmissions to a wireless device, according to an exemplifying

embodiment.

[00030] Figure 7 is a block diagram of an arrangement in a wireless device for selecting a control information reporting state of the wireless device, according to an exemplifying embodiment.

[00031 ] Figure 8 is a block diagram of an arrangement in a network node for transmitting downlink data transmissions to a wireless device, according to an exemplifying embodiment.

Detailed description

[00032] Briefly described, a wireless device and a network node, as well as respective method performed thereby are provided for selecting a control information reporting state of the wireless device, the control information reporting state relating to how to report at least one of channel state information, ACK, and NACK. By evaluating or determining different circumstances of the wireless device, a control information reporting state which is most appropriate for the circumstances of the wireless device is selected. In this manner, the fashion in which the wireless device may report at least one of channel state information, ACK, and NACK is made dynamic instead of static.

[00033] In this disclosure, the non-limiting term radio network node or simply network node is used. It refers to any type of network node that serves wireless devices and/or is connected to other network node(s) or network element(s) or any radio node from where the wireless device receives signal(s). Examples of network nodes are Node B, Base Station, BS, Multi-Standard Radio, MSR, node such as MSR BS, eNode B, eNB, network controller, Radio Network Controller, RNC, Base Station Controller, BSC, relay, donor node controlling relay, Base Transceiver Station, BTS, Access Point, AP, transmission points, transmission nodes, Remote Radio Unit, RRU, Remote Radio Head, RRH, nodes in Distributed Antenna System, DAS. Etc.

[00034] Further in this disclosure, the non-limiting term wireless device is used, t refers to any type of wireless device that communicates with a radio network node in a cellular or mobile communication system. Examples of a wireless device are a User Equipment, UE, target device, Device to Device, D2D, machine type UE or UE capable of Machine to Machine, M2M, communication, Personal Digital Assistant, PDA, iPAD, Tablet, mobile terminals, smart phone, Laptop Embedded Equipped, LEE, Laptop Mounted Equipment, LME, USB dongles, vehicles comprising means for communicating with e.g. network nodes etc.

[00035] The embodiments are described in particular for Universal Mobile Telecommunications System Terrestrial Radio Access, UTRA / High Speed Packet Access, HSPA. The embodiments are however applicable to any Radio Access Technology, RAT, or multi-RAT system where the wireless device operates using multiple carriers e.g. Long Term Evolution, LTE, Frequency Division Duplex, FDD / Time Division Duplex, TDD, Global System for Mobile Communication, GSM / GSM EDGE Radio Access Network, GERAN, Wi Fi, Wireless Local Area Network, WLAN, WiMax, Code Division Multiple Access, CDMA2000, etc.

[00036] The embodiments are applicable to single carrier as well as to

multicarrier, MC, or carrier aggregation, CA, operation of the wireless device. The term CA is also called (e.g. interchangeably called) "multi-carrier system", "multi- cell operation", "multi-carrier operation", "multi-carrier" transmission and/or reception.

[00037] Embodiments of such a method performed by a wireless device for selecting a control information reporting state of the wireless device, the control information reporting state relating to how to report at least one of channel state information, acknowledgement, ACK, and negative ACK, NACK will now be described with reference to figures 1e and 1f.

[00038] Figure 1e illustrates the method comprising determining 1 10 at least one characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node; and selecting 120 a first or a second control information reporting state to use based on the determined at least one

characteristic.

[00039] The characteristics influencing the ability of the wireless device to receive downlink transmissions from the network node may vary substantially depending on different factors, e.g. the current radio conditions at the current location of the wireless device. There may be several different characteristics influencing the ability of the wireless device to receive downlink transmissions from the network node as will be described in more detail below. The characteristics may reflect the particular circumstances of the wireless device at the current time and current location. As described above, wireless devices may typically move about within the coverage area of the wireless communication network. The coverage area of the wireless communication network generally comprises a plurality of cells, wherein each cell is a coverage area of a network node. A wireless device may be located relatively close to the network node and thus probably has good or favourable radio conditions, i.e. good channel quality. A wireless device may be located relatively far from the network node and thus probably has bad or unfavourable radio conditions, i.e. bad channel quality. There may be buildings or other hinders or objects located between the network node and the wireless device having a detrimental effect on the channel quality. Further, there may be relatively few or a relatively large amount of wireless device in the same cell, there may be an unfavourable interference situation within the cell or at cell borders between cells, depending e.g. on the technology of the wireless communication network. All these factors or circumstances, and many other not mentioned, may have a substantial effect on the channel quality.

[00040] If the wireless device is experiencing problems with the channel quality in the downlink, similar problems may exist on the uplink channel since the uplink and downlink channel may have similar path loss or path gain.

[00041 ] One example of determining that the downlink channel quality is poor or bad is by measuring a received downlink signal strength. Another example is by receiving a request, from the network node, for a packet a plurality of times. For example, if the wireless device receives a first request for packet X and then transmits packet X, and then receives a second request for packet X, the wireless device may again transmit packet X or determine that the downlink channel is too corrupted to receive data from the network node. However, if the wireless device transmits packet X, and then receives a third request for packet X, the wireless device may again transmit packet X or determine that the downlink channel is too corrupted to receive data from the network node. The number of allowed retransmissions before determining that the downlink channel is too corrupted to receive data from the network node may be predetermined by an operator and/or may be received e.g. by Radio Resource Control, or may be hardcoded into the wireless device.

[00042] Another example of determining that the downlink channel quality is poor or bad is by the wireless device receiving packet Y and sending an ACK for packet Y, and then receiving packet Y again. If this happens, the ACK sent by the wireless device to the network node has been corrupted during transmission to be interpreted as a NACK by the network node. As for the example above, the wireless device may send a second ACK and possible thereafter receiving packet Y a third time. The number of times the wireless device may receive a packet before determining that the downlink, having similar channel quality as the uplink, is too corrupted to receive data from the network node may be predetermined by an operator and/or may be received e.g. by Radio Resource Control, or may be hardcoded into the wireless device.

[00043] The above examples relate to situations where the at least one characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node is negative. The at least one characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node may of course be positive meaning that no, or relatively few retransmissions in either uplink or downlink occur.

[00044] As will be described below, there are other examples of characteristics influencing the ability of the wireless device to receive downlink transmissions from the network node which may be taken into consideration.

[00045] Once the wireless device has determined the at least one characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node, the wireless device selects 120 a first or a second control information reporting state to use based on the determined at least one

characteristic.

[00046] The method performed by the wireless device may have several possible advantages. One possible advantage is that the signalling overhead of HS- DPCCH may be reduced and hence power may be saved, especially in situations where the ability of the wireless device to receive downlink transmissions from the network node is impaired. The power that may be saved may be used for other data traffic or voice channels. Moreover, interference to other uplink transmitting wireless devices may be reduced.

[00047] The first control information reporting state comprises at least one of (i) the wireless device sending ACK or NACK in response to a received transmission, (ii) the wireless device sending the ACK or NACK at nominal transmission power,

(iii) the wireless device sending Channel State Information, CSI, at a nominal transmission power, and (iv) the wireless device sending CSI at a predetermined time intervals.

[00048] The wireless device is generally expected to (i) send and ACK if a received transmission was successful and a NACK if the received transmission was unsuccessful in order for the network node to know if it should retransmit the packet or not. The wireless device is further expected to (ii) transmit the ACK and the NACK at nominal transmission power. Further, the wireless device is expected to (iv) regularly, or at predetermined time intervals, send CSI (iii) at nominal transmission power to the network node so that the network node is constantly or regularly updated with information pertaining to e.g. the channel quality or conditions.

[00049] All these actions are performed in order to e.g. successfully send and receive transmissions to and from the wireless device. The channel conditions or the channel quality may change rapidly and irregularly depending on many different factors, e.g. movement of the wireless device, number of wireless devices in a cell in which the wireless device is location, location of the wireless device, battery life or usage of the wireless device etc.

[00050] In conditions where e.g. the conditions for the wireless device at ok, good, or favourable, the first control information state is usually selected, wherein the wireless device behaves as described above.

[00051 ] The second control information reporting state comprises at least one of (I) the wireless device not sending the ACK or NACK in response to a received transmission, (II) the wireless device sending the ACK or NACK at a reduced transmission power, (III) the wireless device sending CSI, at a reduced

transmission power compared to the nominal transmission power, and (IV) the wireless device sending CSI less frequently compared to at the predetermined time intervals. [00052] As a contrast to when the conditions for the wireless device at ok, good, or favourable, the conditions for the wireless device may be poor, bad or unfavourable. Merely as an example, the channel conditions or channel quality is so poor that retransmissions are necessary relatively often, the battery life of the wireless device is short or low, e.g. below a battery threshold value, such that the wireless device runs the risk of shut-down.

[00053] If this is the case, the wireless device selects the second control information reporting state. If e.g. the channel quality is so poor that relatively many retransmissions are needed, e.g. the number of retransmissions for a packet is more than a feedback threshold value, the wireless device may determine that the channel conditions are so poor or unfavourable that it is no use in sending ACK and/or NACK and hence selects the second control information reporting state, wherein the wireless device in an example simply refrains from sending ACKs/NACKs in response to a received packet. In this manner, the load of the air interface may possible be somewhat reduced.

[00054] In another example, the battery life of the wireless device is so short or low, e.g. below the battery threshold value, such that the wireless device runs the risk of shut-down. Then the wireless device may select the second control information reporting state and send the ACKs/NACKs at reduced transmission power, in order to save battery power.

[00055] As described above, the wireless device performed different kinds of measurements and also sends CSI reports. If, e.g. the battery life of the wireless device is so short or low, e.g. below the battery threshold value, such that the wireless device runs the risk of shut-down, the wireless device may select the second control information reporting state and send the PCI(s) at reduced transmission power, in order to save battery power. Alternatively, or additionally, the wireless device may send the PCI(s) at reduced transmission power, in order to save battery power.

[00056] In an example, the characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node is at least one of (a) non-corrupted or corrupted ACK and/or NACK messages transmitted on an uplink control channel, (b) the battery life status of the wireless device, (c) the location of the wireless device within a cell of the network node, (d) the power headroom of the wireless device, (e) the travelling speed of the wireless device or (f) the presence or absence of downlink data transmissions from the network node during a predefined period of time.

[00057] As briefly described and exemplified above, there may be different characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node.

[00058] The wireless device may determine that (a) the ACKs and/or the NACKs that the wireless device transmits in response to received packets from the network node are non-corrupted or corrupted. If the wireless device successfully receives packet X, sends an ACK, then receives packet X+1 , send an ACK and receives packet X+2, then the wireless device may determine that the ACKs and/or the NACKs are non-corrupted since the network nodes behaves in the manner it should if the ACKs and NACKs are received by the network node.

[00059] However, if the wireless device successfully receives packet X, sends and ACK, receives packet X again, sends and ACK and receives packet X yet again, the wireless device may determine that the ACKs that are transmitted becomes corrupted on their way to the network node since the network node behaves as if it received a NACK and not an ACK. In such a situation, the wireless device may determine that the channel quality or channel conditions are so poor that there is no use in trying to receive transmissions from the network node or reporting any ACK/NACK. If so, the wireless device may select the second control information reporting state and refrain from sending ACKs/NACKs.

[00060] The wireless device is generally powered by a battery, which may be everything from fully charged to empty. If the battery life (b) of the wireless device is relatively low, e.g. below the battery threshold value, then the wireless device may run the risk of involuntarily shutting down. In order to save battery, the wireless device may select the second control information reporting state and do any of, or all of, the possible actions in the second control information reporting state, (l)-(IV), described above.

[00061 ] Another characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node is (c) the location of the wireless device within a cell of the network node. Generally, the closer the wireless device is to the network node, the better the channel quality. Likewise, generally, the further away wireless device is from the network node, the poorer the channel quality. If the channel conditions are poor enough, as described and exemplified above, the wireless device may select the second control information reporting state.

[00062] Yet an example of a characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node is (d) the power headroom of the wireless device. The power headroom indicates how much transmission power is left for the wireless device to use in addition to the power being used by a current transmission. If the power headroom is relatively low, e.g. below a power headroom threshold, then the wireless device may select the second control information reporting state.

[00063] Another example of a characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node is (e) the travelling speed of the wireless device. As described above, a wireless device may move about within the coverage area of the wireless communication network. Merely as a first example, the wireless device may be a mobile telephone wherein a user of the mobile telephone is walking about, thus the channel conditions may change relatively slowly. As a second example, the wireless device is a car, or comprised in a car, driving at relatively high speed on a highway, thus the channel conditions may change relatively fast. If the channel quality is bad such that a large amount of retransmissions need to be performed and the wireless device is travelling slowly or even not moving, then the channel conditions may not be very likely to change in the very near future and the wireless device may select the second control information reporting state. On the other hand, if the wireless device is traveling fast, then the channel conditions may be very likely to change in the very near future and the wireless device may select the first control information reporting state, even if the channel quality is bad, since the channel conditions may soon improve.

[00064] Still another example of a characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node is (f) the presence or absence of downlink data transmissions from the network node during a predefined period of time. If there are no downlink data transmissions from the network node during a predefined period of time, the wireless device may e.g. not need to send (IV) the CSI as frequently as compared to at the predetermined time intervals when the wireless device is engaged in a data reception or transmission session with the network node. Since the CSI may be used by the network node to efficiently keep updated with the current channel conditions, it may not be as important to keep updated if the wireless device is not actively engaged in communication with the network node as when the wireless device is actively engaged in communication with the network node. Consequently, if the

characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node e.g. indicates (f) the absence of downlink data transmissions from the network node during a predefined period of time, the wireless device may select the second control information reporting state and send the CSI less frequently.

[00065] The method may thus further comprise selecting the second control information reporting state when at least one of: (A) the ACK or NACK message transmitted on the uplink control channel is corrupted, (B) the battery status of the wireless device is below a battery threshold, (C) the location of the wireless device within the cell is above a distance threshold with regard to the network node, (D) the power headroom of the wireless device is below a power threshold, (E) the travelling speed of the wireless device is above a speed threshold, and (F) there is an absence of downlink data transmissions from the network node during the predefined period of time; otherwise selecting the first control information reporting state. [00066] Different conditions, or threshold values, may be defined with respect to the different characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node. For example in case (A) the ACK or NACK message transmitted on the uplink control channel is corrupted, a feedback threshold may be defined which indicates the number of retransmissions that may occur of a downlink or uplink transmission before the wireless device selects the second control information reporting state. The number of

retransmissions corresponds to the number of ACKs or NACKs that are allowed to be sent with regards to the downlink or uplink transmission before the wireless device selects the second control information reporting state.

[00067] Thus when the number of retransmissions that may occur of the downlink or uplink transmission (or the number of ACKs or NACKs that are allowed to be sent with regards to the downlink or uplink transmission) is below the feedback threshold, the wireless device selects the first control information reporting state; and once the number of retransmissions (or the number of ACKs or NACKs that are allowed to be sent with regards to the downlink or uplink transmission) that may occur of the downlink or uplink transmission is equal to or above the feedback threshold, the wireless device selects the second control information reporting state.

[00068] When the characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node is (C) the location of the wireless device within the cell, a distance threshold may be defined. The distance threshold may be defined such that the network node may determine if the wireless is close to the cell edge or not. What is considered to be "close to" the cell edge may be up to implementation. Thus, when the location of the wireless device within the cell is above the distance threshold with regard to the network node, the wireless device is by definition close to the cell edge and hence is more likely to suffer from interference from neighbouring network nodes, experience relatively poor channel quality etc. Consequently, then the location of the wireless device within the cell is above the distance threshold with regard to the network node, the wireless device selects the second control information reporting state. [00069] When the characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node is (E) the travelling speed of the wireless device may be compared to the speed threshold. As described above, the wireless device may be moving very slowly or be still, or may be moving relatively fast, e.g. in a car or a train. Thus, if the travelling speed of the wireless device is above the speed threshold, the wireless device selects the second control information reporting state.

[00070] The method may further comprise, when the selection of control information reporting state entails changing from the first to the second control information reporting state, or changing from the second to the first control information reporting state, informing 130 the network node of the selected control information reporting state.

[00071 ] The network node does not need to know if the wireless device is reporting control information according one of the control information reporting states and the wireless device performs the method resulting in that the wireless device selects the same control information reporting state as it is already in when the method is performed. This is since it has no impact on what the network node expects.

[00072] However, if the wireless device selects a different control information reporting state than the one currently in use by the wireless device, the wireless device informs the network node of the selected control information reporting state. Since a change in control information reporting state results in the network node needing to expect control information reporting in a different manner as it is expecting before the change, the network node needs to be informed that the wireless device henceforth will report control information in a different manner as before the change took place. The network node has to know what to expect from the wireless device in order for the cooperation between the network node and the wireless device is to function properly. [00073] Further, the network node may take different actions when it is informed that the wireless device has selected the first or the second control information reporting state, as will be explained in more detail below.

[00074] In an example, informing 130 the network node of the changed control information reporting state comprises transmitting a message comprising a predefined combination of rank information, Rl, and Channel Quality Information, CQI, to the network node, or transmitting a predefined PreCoding Information, PCI, to the network node.

[00075] There are different ways the wireless device may inform 130 the network node of the changed control information reporting state. For example, a new message may be defined for reporting the changed, or selected, control

information reporting state.

[00076] Another example is to modify or use an already existing message or signalling. An example of modifying or use an already existing message or signalling is to use a predefined Rl and CQI to the network node. Rl is an important input to the network node, in selection of the transmission layer in downlink data transmission. CQI may have significant impact on the system performance. There are two types of CQI report: periodic and aperiodic. The CQI informs the network node of a current channel quality so that the network node may e.g. select an appropriate Modulation and Coding Scheme, MCS, to be used for downlink transmissions.

[00077] There are predetermined values of e.g. CQI that convey different information to the network node. By using a predefined combination of Rl and CQI, the wireless device informs which control information reporting state it has selected. There are a plurality of CQI indices, e.g. CQI-0, CQI-1 , CQI-2, CQI- 15.

[00078] In yet an example, Rl=1 in combination with CQI=00000 is transmitted by the wireless device when it changes from the first to the second control information reporting state; wherein Rl= 2, 3 or 4 in combination with CQI=1 1 1 1 is transmitted by the wireless device when it changes control information reporting state from second to first.

[00079] There may be several alternative examples of which respective combination of Rl and CQI that means the wireless device changes control information reporting state from first to second control information reporting state and from second to first control information reporting state.

[00080] In a first example, Rl=1 in combination with CQI=00000 is transmitted by the wireless device when it changes from the first to the second control information reporting state; and Rl= 2, 3 or 4 in combination with CQI=1 1 1 1 is transmitted by the wireless device when it changes control information reporting state from second to first, wherein the CQI may be CQI-1 or CQI-2.

[00081 ] In a second example, Rl=2 in combination with CQI-1 =1 1 1 1 is

transmitted by the wireless device when it changes from the first to the second control information reporting state; and Rl=3 in combination with CQI-1 =1 1 1 1 is transmitted by the wireless device when it changes from the second to the first control information reporting state.

[00082] In a third example, Rl=2 in combination with CQI-1 =1 1 1 1 is transmitted by the wireless device when it changes from the first to the second control information reporting state; and Rl=2 in combination with CQI-2=1 1 1 1 is transmitted by the wireless device when it changes from the second to the first control information reporting state.

[00083] There are many other examples of combinations of Rl and CQI that may be predefined to enable the wireless device informing the network node of which control information reporting state it selects and changes to.

[00084] In still an example the PCI is represented by four bits, i.e. 0000 to 1 1 1 1 , wherein a first predefined PCI is transmitted by the wireless device when it changes from the first to the second control information reporting state and a second predefined PCI is transmitted by the wireless device when it changes from the second to the first control information reporting state. [00085] Also here, different values of PCI have different meaning and some PCI values are predefined to convey different information. However, not all possible values of PCI are predefined to convey individual pieces of information; and at least two of those non-predefined values of PCI may be used to define selecting the first control information reporting state and selecting the second control information reporting state respectively.

[00086] Embodiments herein also relate to a method performed by a network node for transmitting downlink data transmissions to a wireless device, the wireless device employing at least two control information reporting states relating to how the wireless device reports at least one of channel state information, ACK, and NACK, for downlink transmissions from the network node. Embodiments of such a method will now be described with reference to figure 2.

[00087] Figure 2 is a flowchart of a method performed by a network node for transmitting downlink data transmissions to a wireless device. Figure 2 illustrates the method comprising receiving 210 information from the wireless device that the wireless device has changed control information reporting state, wherein the at least two control information reporting states are a first control information reporting state and a second control information reporting state. The method comprises when the change of control information reporting states is from the first to the second control information reporting state: refraining 220 from transmitting downlink data transmissions to the wireless device; and when the change of control information reporting states is from the second to the first control information reporting state: transmitting 230 downlink data transmissions to the wireless device.

[00088] The network node may take different actions depending on which control information reporting state the wireless device has selected, or is using. For example, when the wireless device is using the second control information reporting state, at least one characteristics influencing the ability of the wireless device to receive downlink transmissions from the network node is unfavourable in such a manner that the wireless device has selected the second control information reporting state. When the wireless device is in the second control information reporting state, it may e.g. have low battery life or bad radio conditions, wherein the wireless device may have difficulty receiving downlink transmission, and thus also having difficulty transmitting uplink transmissions.

[00089] When the wireless device is using the second control information reporting state, the network node may refrain from transmitting downlink data transmissions to the wireless device since the wireless device may possibly not be able to successfully receive the downlink data transmissions. In this manner, valuable radio resources may be saved instead of being wasted.

[00090] On the other hand, when the wireless device is using the first control information reporting state, the wireless device is probably not experiencing any severe hinders for receiving downlink transmissions, neither due to bad channel quality nor due to low battery life. Hence, when the wireless device is using the first control information reporting state, the network node may transmit downlink data transmissions to the wireless device.

[00091 ] The network node may be informed of which control information reporting state the wireless device is using, or has selected, as described above, e.g. by means of a message comprising a predefined combination of Rl and CQI, or a predefined PCI. Both the wireless device and the network node has knowledge of the meaning of the different predefined combinations of Rl and CQI, or predefined PCIs.

[00092] The method performed by the network node may have the same possible advantages as the method performed by the wireless device. One possible advantage is One possible advantage is that the signalling overhead of HS- DPCCH may be reduced and hence power may be saved, especially in situations where the ability of the wireless device to receive downlink transmissions from the network node is impaired. The power that may be saved may be used for other data traffic or voice channels. Moreover, interference to other uplink transmitting wireless devices may be reduced. [00093] Embodiments herein also relate to a wireless device for selecting a control information reporting state of the wireless device, the control information reporting state relating to how to report at least one of channel state information, ACK, and NACK. The wireless device has the same objects, technical features and advantages as the method performed by the wireless device as described above. The wireless device will only be described in brief in order to avoid unnecessary repetition.

[00094] Figures 3 and 5 are block diagrams of a wireless device for selecting a control information reporting state of the wireless device.

[00095] Figures 3 and 5 illustrate the wireless device being configured for determining at least one characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node; and selecting a first or a second control information reporting state to use based on the determined at least one characteristic.

[00096] The wireless device 300, 500 may be implemented or realised in different ways. An exemplifying implementation is illustrated in figure 3. Figure 3 illustrates the wireless device 300 comprising a processor 321 and memory 322, the memory comprising instructions, e.g. by means of a computer program 323, which when executed by the processor 321 causes the wireless device 300 to determine at least one characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node; and to select a first or a second control information reporting state to use based on the determined at least one characteristic.

[00097] An alternative exemplifying implementation of the wireless device 300, 500 is illustrated in figure 5. Figure 5 illustrates the wireless device 500

comprising a determining unit 503 for determining at least one characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node; and a selecting unit 504 for selecting a first or a second control information reporting state to use based on the determined at least one

characteristic. [00098] The wireless device may have the same several possible advantages as the method performed by the wireless device described above. One possible advantage is that the signalling overhead of HS-DPCCH may be reduced and hence power may be saved, especially in situations where the ability of the wireless device to receive downlink transmissions from the network node is impaired. The power that may be saved may be used for other data traffic or voice channels. Moreover, interference to other uplink transmitting wireless devices may be reduced.

[00099] According to an embodiment, the first control information reporting state comprises at least one of (i) the wireless device sending ACK or NACK in response to a received transmission, (ii) the wireless device sending the ACK or NACK at nominal transmission power, (iii) the wireless device sending Channel State Information, CSI, at a nominal transmission power, and (iv) the wireless device sending CSI at a predetermined time intervals.

[000100] According to yet an embodiment, the second control information reporting state comprises at least one of (I) the wireless device not sending the ACK or NACK in response to a received transmission, (II) the wireless device sending the ACK or NACK at a reduced transmission power, (III) the wireless device sending CSI, at a reduced transmission power compared to the nominal transmission power, and (IV) the wireless device sending CSI less frequently compared to at the predetermined time intervals.

[000101 ] According to still an embodiment, the characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node is at least one of (a) non-corrupted or corrupted ACK and/or NACK messages transmitted on an uplink control channel, (b) the battery life status of the wireless device, (c) the location of the wireless device within a cell of the network node, (d) the power headroom of the wireless device, (e) the travelling speed of the wireless device or (f) the presence or absence of downlink data transmissions from the network node during a predefined period of time. [000102] According to another embodiment, the wireless device 300, 500 further is configured for selecting the second control information reporting state when at least one of: (A) the ACK or NACK message transmitted on the uplink control channel is corrupted, (B) the battery status of the wireless device is below a battery threshold, (C) the location of the wireless device within the cell is above a distance threshold with regard to the network node, (D) the power headroom of the wireless device is below a power threshold, (E) the travelling speed of the wireless device is above a speed threshold, and (F) there is an absence of downlink data transmissions from the network node during the predefined period of time;

otherwise selecting the first control information reporting state.

[000103] According to yet an embodiment, the wireless device 300, 500 further is configured for, when the selection of control information reporting state entails changing from the first to the second control information reporting state, or changing from the second to the first control information reporting state, informing the network node of the selected control information reporting state.

[000104] According to still an embodiment, the wireless device is configured for informing the network node of the changed control information reporting state by transmitting a message comprising a predefined combination of rank information, Rl, and Channel Quality Information, CQI, to the network node, or transmitting a predefined PreCoding Information, PCI, to the network node.

[000105] According to yet another embodiment, the wireless device is configured for transmitting Rl=1 in combination with CQI=00000 when the wireless device changes from the first to the second control information reporting state; wherein the wireless device is configured for transmitting Rl= 2, 3 or 4 in combination with CQI=1 1 1 1 when the wireless device changes control information reporting state from second to first.

[000106] According to an embodiment, the PCI is represented by four bits, i.e. 0000 to 1 1 1 1 , wherein the wireless device is configured for transmitting a first predefined PCI when it changes from the first to the second control information reporting state, and wherein the wireless device is configured for transmitting a second predefined PCI when it changes from the second to the first control information reporting state.

[000107] Embodiments herein also relate to a network node for transmitting downlink data transmissions to a wireless device, the wireless device employing at least two control information reporting states relating to how the wireless device reports at least one of channel state information, ACK, and NACK for downlink transmissions from the network node. The network node has the same objects, technical features and advantages as the method performed by the network node as described above. The network node will only be described in brief in order to avoid unnecessary repetition.

[000108] Figures 4 and 6 are block diagrams of a network node 400, 600 for selecting a control information reporting state of the wireless device.

[000109] Figures 4 and 6 illustrate the network node 400, 600 being configured for receiving information from the wireless device that the wireless device has changed control information reporting state, wherein the at least two control information reporting states are a first control information reporting state and a second control information reporting state. The network node 400, 600 is further configured to, when the change of control information reporting states is from the first to the second control information reporting state: refraining from transmitting downlink data transmissions to the wireless device; and when the change of control information reporting states is from the second to the first control information reporting state: transmitting downlink data transmissions to the wireless device.

[0001 10] The network node 400, 600 may be implemented or realised in different ways. An exemplifying implementation is illustrated in figure 4. Figure 4 illustrates the network node 400 comprising a processor 421 and memory 422, the memory comprising instructions, e.g. by means of a computer program 423, which when executed by the processor 421 causes the network node 400 to receive

information from the wireless device that the wireless device has changed control information reporting state, wherein the at least two control information reporting states are a first control information reporting state and a second control information reporting state. The memory 422 further comprising instructions, e.g. by means of a computer program 423, which when executed by the processor 421 causes the network node 400 to when the change of control information reporting states is from the first to the second control information reporting state: refrain from transmitting downlink data transmissions to the wireless device; and when the change of control information reporting states is from the second to the first control information reporting state: transmit downlink data transmissions to the wireless device.

[0001 1 1 ] An alternative exemplifying implementation of the network node 400, 600 is illustrated in figure 6. Figure 6 illustrates the network node 600 comprising a receiving unit 603 for receiving information from the wireless device that the wireless device has changed control information reporting state, wherein the at least two control information reporting states are a first control information reporting state and a second control information reporting state. The network node 600 further comprises a transmitting unit 604 for transmitting downlink data transmissions to the wireless device when the change of control information reporting states is from the second to the first control information reporting state, wherein the network node 600 refrains from transmitting downlink data

transmissions to the wireless device when the change of control information reporting states is from the first to the second control information reporting state.

[0001 12] The network node 400, 600 has the same possible advantages as the method performed by the network node. One possible advantage is One possible advantage is that the signalling overhead of HS-DPCCH may be reduced and hence power may be saved, especially in situations where the ability of the wireless device to receive downlink transmissions from the network node is impaired. The power that may be saved may be used for other data traffic or voice channels. Moreover, interference to other uplink transmitting wireless devices may be reduced.

[0001 13] Figure 3 also illustrates the wireless device 300 comprising a memory 310. It shall be pointed out that figure 3 is merely an exemplifying illustration and memory 310 may be optional, be a part of the memory 322 or be a further memory of the wireless device. The memory may for example comprise information relating to the wireless device 300, or e.g. statistics of operation of the wireless device 300, just to give a couple of illustrating examples. Figure 3 further illustrates the wireless device 300 comprising processing means 320, which comprises the memory 322 and the processor 321 . Still further, figure 3 illustrates the wireless device 300 comprising a communication unit 330. The communication unit 330 may comprise an interface through which the wireless device 300 communicates with other nodes or entities of the communication network. Figure 3 also illustrates the wireless device 300 comprising further functionality 340. The further

functionality 340 may comprise hardware of software necessary for the wireless device 300 to perform different tasks that are not disclosed herein.

[0001 14] Figure 4 also illustrates the network node 400 comprising a memory 410. It shall be pointed out that figure 4 is merely an exemplifying illustration and memory 410 may be optional, be a part of the memory 422 or be a further memory of the network node. The memory may for example comprise information relating to the network node 400, or to statistics of operation of the network node 400, just to give a couple of illustrating examples. Figure 4 further illustrates the network node 400 comprising processing means 420, which comprises the memory 422 and the processor 421. Still further, figure 4 illustrates the network node 400 comprising a communication unit 430. The communication unit 430 may comprise an interface through which the network node 400 communicates with other nodes or entities of the communication network as well as wireless device of the communication network. Figure 4 also illustrates the network node 300 comprising further functionality 440. The further functionality 440 may comprise hardware of software necessary for the network node 400 to perform different tasks that are not disclosed herein. Merely as an illustrative example, the further functionality may comprise a scheduler for scheduling transmissions from the network node 400 and/or for transmissions from wireless devices with which the network node 400 communicates with. [0001 15] In figure 5, the wireless device 500 is also illustrated comprising a communication unit 501. Through this unit, the wireless device 500 is adapted to communicate with other nodes and/or entities in the wireless communication network. The communication unit 501 may comprise more than one receiving arrangement. For example, the communication unit 501 may be connected to both a wire and an antenna, by means of which the wireless device 500 is enabled to communicate with other nodes and/or entities in the wireless communication network. Similarly, the communication unit 501 may comprise more than one transmitting arrangement, which in turn is connected to both a wire and an antenna, by means of which the wireless device 500 is enabled to communicate with other nodes and/or entities in the wireless communication network. The wireless device 500 further comprises a memory 502 for storing data. Further, the wireless device 500 may comprise a control or processing unit (not shown) which in turn is connected to the different units 503-504. It shall be pointed out that this is merely an illustrative example and the wireless device 500 may comprise more, less or other units or modules which execute the functions of the wireless device 500 in the same manner as the units illustrated in figure 5.

[0001 16] It should be noted that figure 5 merely illustrates various functional units in the wireless device 500 in a logical sense. The functions in practice may be implemented using any suitable software and hardware means/circuits etc. Thus, the embodiments are generally not limited to the shown structures of the wireless device 500 and the functional units. Hence, the previously described exemplary embodiments may be realised in many ways. For example, one embodiment includes a computer-readable medium having instructions stored thereon that are executable by the control or processing unit for executing the method steps in the wireless device 500. The instructions executable by the computing system and stored on the computer-readable medium perform the method steps of the wireless device 500 as set forth in the claims.

[0001 17] In figure 6, the network node 600 is also illustrated comprising a communication unit 601 . Through this unit, the network node 600 is adapted to communicate with other nodes and/or entities in the wireless communication network. The communication unit 601 may comprise more than one receiving arrangement. For example, the communication unit may be connected to both a wire and an antenna, by means of which the network node 600 is enabled to communicate with other nodes and/or entities in the wireless communication network. Similarly, the communication unit 601 may comprise more than one transmitting arrangement, which in turn is connected to both a wire and an antenna, by means of which the network node 600 is enabled to communicate with other nodes and/or entities in the wireless communication network. The network node 600 further comprises a memory 602 for storing data. Further, the network node 600 may comprise a control or processing unit (not shown) which in turn is connected to the different units 603-604. It shall be pointed out that this is merely an illustrative example and the network node 600 may comprise more, less or other units or modules which execute the functions of the network node 600 in the same manner as the units illustrated in figure 6.

[0001 18] It should be noted that figure 6 merely illustrates various functional units in the network node 600 in a logical sense. The functions in practice may be implemented using any suitable software and hardware means/circuits etc. Thus, the embodiments are generally not limited to the shown structures of the network node 600 and the functional units. Hence, the previously described exemplary embodiments may be realised in many ways. For example, one embodiment includes a computer-readable medium having instructions stored thereon that are executable by the control or processing unit for executing the method steps in the network node 600. The instructions executable by the computing system and stored on the computer-readable medium perform the method steps of the network node 600 as set forth in the claims.

[0001 19] Figure 7 schematically shows an embodiment of an arrangement 700 in a wireless device 300, 500. Comprised in the arrangement 700 in the wireless device 300, 500 are here a processing unit 706, e.g. with a Digital Signal

Processor, DSP. The processing unit 706 may be a single unit or a plurality of units to perform different actions of procedures described herein. The arrangement 700 in the wireless device 300, 500 may also comprise an input unit 702 for receiving signals from other entities, and an output unit 704 for providing signal(s) to other entities. The input unit and the output unit may be arranged as an integrated entity or as illustrated in the example of figure 5, as one or more interfaces 501 .

[000120] Furthermore, the arrangement 700 in the wireless device 300, 500 comprises at least one computer program product 708 in the form of a non-volatile memory, e.g. an Electrically Erasable Programmable Read-Only Memory,

EEPROM, a flash memory and a hard drive. The computer program product 708 comprises a computer program 710, which comprises code means, which when executed in the processing unit 706 in the arrangement 700 in the wireless device 300, 500 causes the wireless device to perform the actions e.g. of the procedure described earlier in conjunction with figures 1e and 1f.

[000121 ] The computer program 710 may be configured as a computer program code structured in computer program modules 710a-710e. Hence, in an

exemplifying embodiment, the code means in the computer program of the arrangement 700 in the wireless device 300, 500 comprises a determining unit, or module, for determining at least one characteristic influencing the ability of the wireless device to receive downlink transmissions from the network node. The computer program further comprises a selecting unit, or module, for selecting a first or a second control information reporting state to use based on the

determined at least one characteristic.

[000122] The computer program modules could essentially perform the actions of the flow illustrated in figure 1 a, to emulate the wireless device 500. In other words, when the different computer program modules are executed in the processing unit 706, they may correspond to the units 503-504 of figure 5.

[000123] Figure 8 schematically shows an embodiment of an arrangement 800 in a network node 400, 600. Comprised in the arrangement 800 in the network node 400, 600 are here a processing unit 806, e.g. with a Digital Signal Processor. The processing unit 806 may be a single unit or a plurality of units to perform different actions of procedures described herein. The arrangement 800 in the network node 400, 600 may also comprise an input unit 802 for receiving signals from other entities, and an output unit 804 for providing signal(s) to other entities. The input unit and the output unit may be arranged as an integrated entity or as illustrated in the example of figure 6, as one or more interfaces 601 .

[000124] Furthermore, the arrangement 800 in the network node 400, 600 comprises at least one computer program product 808 in the form of a non-volatile memory, e.g. an EEPROM, a flash memory and a hard drive. The computer program product 808 comprises a computer program 810, which comprises code means, which when executed in the processing unit 806 in the arrangement 800 in the network node 400, 600 causes the arrangement 800 in the network node 400, 600 to perform the actions e.g. of the procedure described earlier in conjunction with figure 2.

[000125] The computer program 810 may be configured as a computer program code structured in computer program modules 810a-810e. Hence, in an exemplifying embodiment, the code means in the computer program of the arrangement 800 in the network node 400, 600 comprises a receiving unit, or module, for receiving information from the wireless device that the wireless device has changed control information reporting state, wherein the at least two control information reporting states are a first control information reporting state and a second control information reporting state. The computer program further comprises a transmitting unit, or module, for transmitting downlink data

transmissions to the wireless device when the change of control information reporting states is from the second to the first control information reporting state, wherein the network node refrains from transmitting downlink data transmissions to the wireless device when the change of control information reporting states is from the first to the second control information reporting state.

[000126] The computer program modules could essentially perform the actions of the flow illustrated in figure 2, to emulate the network node 600. In other words, when the different computer program modules are executed in the processing unit 806, they may correspond to the units 603-604 of figure 6. [000127] Although the code means in the respective embodiments disclosed above in conjunction with figures 5 and 6 are implemented as computer program modules which when executed in the respective processing unit causes the wireless device and the network node respectively to perform the actions described above in the conjunction with figures mentioned above, at least one of the code means may in alternative embodiments be implemented at least partly as hardware circuits.

[000128] The processor may be a single Central Processing Unit, CPU, but could also comprise two or more processing units. For example, the processor may include general purpose microprocessors; instruction set processors and/or related chips sets and/or special purpose microprocessors such as Application Specific Integrated Circuits, ASICs. The processor may also comprise board memory for caching purposes. The computer program may be carried by a computer program product connected to the processor. The computer program product may comprise a computer readable medium on which the computer program is stored. For example, the computer program product may be a flash memory, a Random-Access Memory RAM, Read-Only Memory, ROM, or an EEPROM, and the computer program modules described above could in alternative embodiments be distributed on different computer program products in the form of memories within the wireless device and the network node

respectively.

[000129] It is to be understood that the choice of interacting units, as well as the naming of the units within this disclosure are only for exemplifying purpose, and nodes suitable to execute any of the methods described above may be configured in a plurality of alternative ways in order to be able to execute the suggested procedure actions.

[000130] It should also be noted that the units described in this disclosure are to be regarded as logical entities and not with necessity as separate physical entities.

[000131 ] While the embodiments have been described in terms of several embodiments, it is contemplated that alternatives, modifications, permutations and equivalents thereof will become apparent upon reading of the specifications and study of the drawings. It is therefore intended that the following appended claims include such alternatives, modifications, permutations and equivalents as fall within the scope of the embodiments and defined by the pending claims.