WO2015099585A1

WO2015099585A1 - Reporting ignored uplink scheduling grants

Info

Publication number: WO2015099585A1
Application number: PCT/SE2013/051619
Authority: WO
Inventors: Stefan Parkvall; Magnus Stattin
Original assignee: Telefonaktiebolaget L M Ericsson (Publ)
Priority date: 2013-12-23
Filing date: 2013-12-23
Publication date: 2015-07-02

Abstract

It is disclosed a wireless device (30), a radio network node (32) and methods therefore, for communicating in a network. The wireless device determines whether resources indicated by an uplink grant are unused, and transmits information to the radio network node informing that the resources as indicated by the uplink are unused, when the resources are unused.

Description

REPORTING IGNORED UPLINK SCHEDULING GRANTS

TECHNICAL FIELD

This disclosure relates to ignoring of uplink scheduling grants for transmission. In more particular, it relates to a wireless device, a radio network node and methods therein, for providing information informing that resources indicated by an uplink scheduling grant are unused.

BACKGROUND

As the number of wireless devices increases, there is an endeavour to increase resource utilization in radio frequency spectrum. The amount of licensed spectrum is limited and has a price in terms of license cost.

Transmissions in long term evolution (LTE) are fully scheduled, i.e. an evolved NodeB (eNodeB) is in control of when and on what resources a user equipment (UE) shall be transmitting.

Figure 1 schematically presents a network, in which a wireless device 12, such as a UE, 12 is served by a base station 14, such as an eNodeB.

In the uplink, resources are handled by sending uplink scheduling grants to the UEs from the eNodeB. Each uplink scheduling grant contains information on e.g. the frequency resources on which the terminal should transmit, information related to payload size, and modulation and coding to use.

The uplink grants are sent to the UE prior to the scheduled uplink transmission. In LTE, a UE has about 3 ms for processing of the uplink scheduling grant prior to uplink transmission. An uplink scheduling grant transmitted by an eNodeB in the downlink in a subframe n, applies for uplink transmission in a subframe n+4 for a frequency division duplex (FDD) version of LTE. For a time division duplex (TDD) version of LTE, an uplink grant transmitted in subframe n, apply to transmission in a subframe n+k , where k may be equal to or larger than 4.

In addition, there is a possibility for so-called semi-persistent scheduling where a network provides a UE with scheduling grants in the uplink for multiple subframes according to a preconfigured time periodicity. Semi-persistent scheduling may be useful to reduce the control signalling overhead from dynamic scheduling.

Irrespective of dynamic or semi-static scheduling or the reason for sending a scheduling grant, in LTE the UE always obeys uplink scheduling grants, since there is a principle in LTE of the UE to always follow the uplink scheduling grants.

If there is no or not enough data to fill up the resources indicated in the uplink scheduling grant, the UE will use padding to fill the resources indicated in the uplink scheduling grant.

In contrast to LTE, transmissions in WiFi are not scheduled but are autonomously handled.

Figure 2 presents a scheme for transmission in WiFi, illustrating a first node 20, and a second node,

22 attempting unscheduled transmission. When the first node 20 has data to transmit, it listens to the channel activity for a certain amount of time, for example 20 microseconds (μβ), and assesses whether the channel is available for transmission. Since the second node 22 is not transmitting any data during the listening time of the first node 20, the first node, 20 assesses that the channel is available for transmission, and may thus start transmission on the channel.

If the second node 22, assesses the channel availability during transmission by the first node 20, the second node 22 assesses that the channel as not available for uplink transmission. The second node 22 then waits a "back-off duration" in time, after which it assesses the channel availability again. Since the first node 20 does not transmit any data during this time, the second node 22 declares the channel available for transmission, after which it may transmit uplink data.

The scheme as presented in Figure 2 is called listen before talk (LBT) since a node has to listen to the channel and assess the availability before it may transmit, i.e. talk. The use of LBT allows WiFi devices to share the spectrum among a multiple of other WiFi nodes. Moreover, the LBT allows WiFi devices to share the spectrum among non-WiFi devices.

Licensed spectrum, for which LTE is designed, provides many benefits in terms of network planning and quality-of-service guarantees, in relation to an unlicensed spectrum. Since the amount of licensed spectrum is limited and has a price in terms of license cost, many operators exploit unlicensed spectrum, which comes at no licensing cost, as a complement in order to offload the LTE networks. In most cases, WiFi based on the IEEE 802.11 family of technologies is the technology used. Although WiFi provides means to access unlicensed spectrum, it has several drawbacks such as limited support for mobility and quality-of-service handling. Recently, the interest in using LTE for accessing unlicensed spectrum has increased.

Carrier aggregation, where a terminal receives or transmits on multiple component carriers, is an integral part of LTE from release 10 onwards. In the LTE specifications, the component carriers correspond to a primary cell (PCell) and secondary cells (SCells).

From the perspective of the wireless device, there is only one PCell, whereas there may be one or more SCells. Cross-carrier scheduling is supported, in which case downlink assignments and uplink scheduling grants relating to one carrier, e.g. an SCell, may be sent on another carrier, e.g. the PCell, using the (enhanced)physical downlink control channel ((E)PDCCH). Similarly, uplink control signalling on physical uplink control channel (PUCCH) from a UE to the eNodeB is transmitted on the PCell regardless of whether it relates to the PCell or a SCell.

An alternative to carrier aggregation is dual connectivity framework currently being developed in 3GPP, for multiple component carriers. In dual connectivity the carriers are associated with different base stations. Dual connectivity applied to licensed and unlicensed spectra, provides flexibility as the licensed and unlicensed accesses are implemented in separate nodes.

This is in contrast to carrier aggregation, where a PCell and a SCell are co-located in the same node or base station. Using dual connectivity provides additional flexibility as the licensed and unlicensed access may be implemented in separate nodes.

As mentioned above, if there is no data to transmit on the resources indicated in the uplink scheduling grant in LTE, a UE will use padding of the resources indicated in the uplink scheduling grant. It is inefficient to transmit arbitrary bits, in absence of meaningful data to transmit.

When extending LTE to access an unlicensed spectrum on a SCell, it may be beneficial and may become a requirement to support LBT. In the downlink, the eNodeB may listen on the channel prior to the start of a subframe and, if the channel is declared available, schedule data transmissions in the subframes following the listening period.

In the uplink, scheduling decisions are taken by the eNodeB in advance of the listening period in the UE. If the UE finds the channel available, it simply follows the scheduling uplink scheduling grant from the eNodeB and transmits in the uplink as illustrated.

If the UE finds the channel to be busy, it cannot transmit in a particular subframe even if a scheduling grant has instructed the UE to do so. The eNodeB, on the other hand, expects a transmission from the UE in the scheduled uplink resources. To the eNodeB the missing transmission in the uplink appears as if the UE did not properly receive the scheduling grant. For this reason the eNodeB may try to address the missing uplink transmission by increasing the robustness in the downlink when transmitting an uplink scheduling grant despite this is not necessary.

There is hence a need for a solution addressing these issues as discussed above.

SUMMARY

It is an object of exemplary embodiments to address at least some of the issues outlined above, and this object and others are achieved by a wireless device, a radio network node and methods therein, according to the appended independent claims, and by embodiments of the exemplary embodiments according to the dependent claims.

According to an aspect, the exemplary embodiments provide a method in a wireless device for communicating with a radio network node. The method comprises receiving from the radio network node an uplink grant indicating first resources. The method also comprises determining whether to use the first resources indicated by the uplink grant. In addition, the method comprises when determining that the first resources indicated by the uplink grant are unused, transmitting to the radio network node information informing that the first resources are unused.

According to another aspect, the exemplary embodiments provide a method in a radio network node for communicating with a wireless device. The method in the radio network node comprises transmitting to the wireless device an uplink grant indicating first resources. This method in the radio network node also comprises receiving from the wireless device information informing that the first resources indicated by the uplink grant are unused. According to yet another aspect, the exemplary embodiments provide a wireless device that is adapted to communicate with a radio network node. The wireless device comprises a receiver, a transmitter, and a processing unit. The processing unit is adapted to receive via the receiver from the radio network node an uplink grant indicating first resources. The processing unit is also adapted to determine whether to use the first resources indicated by the uplink grant. In addition, the processing unit is adapted to transmit via the transmitter to the radio network node information informing that the first resources are unused, when the processing unit has determined that the first resources indicated by the uplink grant are unused.

According to still yet another aspect, the exemplary embodiments provide a radio network node for communicating with a wireless device. The radio network node comprises a receiver, a transmitter, and a processing unit. The processing unit is adapted to transmit via the transmitter an uplink grant indicating first resources to the wireless device. In addition, the processing unit is adapted to receive via the receiver information informing that the first resources indicated by the uplink grant are unused, from the wireless device.

By providing information to the radio network node informing that resources indicated by an uplink grant are unused, the radio network node may estimate the load or collision probability on an unlicensed spectrum, according to some embodiments of the exemplary embodiments.

Also, by providing information to the radio network node informing that resources indicated by an uplink grant are unused, the network node may distinguish an uplink grant that is successfully received by the wireless device from an uplink grant that is not. The radio network node may then choose to adjust power, aggregation level, i.e. the robustness, only when an uplink grant is not successfully received by the wireless device.

It is a further advantage that padding may be avoided by the wireless device when no data is available to be transmitted using the resources indicated by an uplink grant.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described in more detail, and with reference to the accompanying drawings, in which:

Figure 1 schematically illustrates a communication network;

Figure 2 schematically illustrates resource availability check in prior art;

Figure 3 presents a handshake diagram of signalling according to embodiments of the exemplary embodiments;

Figures 4 and 5 present flow charts of methods according to embodiments of the exemplary embodiments;

Figures 6 and 7 schematically present a radio network node according to embodiments of the exemplary embodiments; and Figures 8 and 9 schematically present a wireless device according to embodiments of the exemplary embodiments.

DETAILED DESCRIPTION

In the following description, different embodiments of the exemplary embodiments will be described in more detail, with reference to accompanying drawings. For the purpose of explanation and not limitation, specific details are set forth, such as particular examples and techniques in order to provide a thorough understanding.

A basic idea of embodiments of the exemplary embodiments is to provide feedback to a radio network node about whether resources indicated by uplink scheduling grants are used or not. Hence, information addressed to a radio network node, such as an eNodeB, informing that resources indicated in uplink scheduling grants are unused, may be provided. This is in spite of receiving the uplink scheduling grant from the radio network node.

In order to inform the radio network node about that the wireless device has not used the resources as indicated in a received uplink scheduling grant, information may be provided to the radio network node informing that the resources as indicated by the uplink scheduling grant are unused.

By providing information to the radio network node about that the resources as indicated by the uplink scheduling grant are unused, the radio network node may distinguish between cases in which the uplink scheduling grant was in fact successfully received by the wireless device, and cases in which the uplink scheduling grant was not successfully received. When receiving information informing that resources indicated by an uplink grant are unused, it is concluded that the uplink grant was successfully received by the wireless device. Hence, the radio network node only reacts by increasing the robustness in the downlink in cases in which it is concluded that the uplink grant was not successfully received by the wireless device.

Figure 3 presents a handshake diagram of signaling between a wireless device 30 and a radio network node 32, for gaining information informing that the resources as indicated by an uplink scheduling grant are unused, when determining by the wireless device that the resources are unused.

In 34, the radio network node 32 sends to the wireless device 30 an uplink scheduling grant indicating first resources for uplink transmission. In 36, the wireless device 30 determines whether to use the first resources indicated by the received uplink scheduling grant for uplink transmission. When determining by the wireless device 30 that the first resources are unused, the wireless device 30 transmits, in 38, to the radio network node 32 information informing that the first resources are unused. The radio network node 32 thus receives the transmitted information informing that the first resources indicated in the uplink scheduling grant are unused.

There may be various reasons to why the wireless device 30 determines that first resources indicated by an uplink scheduling grant are unused. These reasons will be described further down. Moreover, it should be mentioned that embodiments of the present exemplary embodiments are applicable to several different cases. In one case, a single carrier is used for communication between the wireless device and the radio network node, and the wireless device determines that resources indicated by an uplink grant on said carrier are unused. Although the wireless device is under control of the radio network node in LTE and that a wireless device shall follow uplink scheduling grants from a serving radio network node, there may be information or instructions provided to the wireless device from the radio network node, which information or instructions supersedes the uplink scheduling grant. For instance, if the wireless device needs to perform random access, the wireless device will not be able to use resources indicated by an uplink scheduling grant.

When there is only one carrier in the uplink and one carrier in the downlink, these are possibly but not necessarily on the same frequency.

Embodiments of the present exemplary embodiments are however also applicable to cases in which there are two or more carriers. Two examples of frameworks for using two or more carriers are carrier aggregation and dual connectivity.

As indicated above, carrier aggregation is an integral part of LTE. In current LTE specifications, the component carriers correspond to a PCell and one or more SCells. Cross-carrier scheduling is supported, in which case downlink assignments and uplink scheduling grants relating to one carrier, e.g. an SCell, may be sent on another carrier, e.g. the PCell, using the (enhanced)physical downlink control channel ((E)PDCCH). Similarly, uplink control signalling on PUCCH from a UE to the eNodeB is transmitted on the PCell regardless of whether it relates to the PCell or a SCell. In carrier aggregation, the PCell and the one or more SCells are co-located in the same radio network node.

In dual connectivity, two carriers are associated with separate radio network nodes.

Carrier aggregation or dual connectivity may be combined with exploiting an unlicensed spectrum. In carrier aggregation, the PCell will then correspond to the licensed spectrum, and the one or more SCells will correspond to an unlicensed spectrum.

Using dual connectivity provides additional flexibility as licensed access and unlicensed access are implemented in separate nodes. Carrier aggregation requires the licensed and unlicensed access to be co- located, i.e. to be located in the same radio network node.

Although embodiments may be described using an emphasis on carrier aggregation framework, the dual connectivity framework may be used equally well.

If there is no data to be transmitted by the wireless device using the resources indicated by the uplink scheduling grant, the wireless device may determine that the resources indicated by the uplink scheduling grant are unused. Instead of using padding, i.e. filling the first resources with arbitrary bits and transmitting said arbitrary bits to the radio network node, the wireless device may as proposed herein send information informing the radio network node that first resources indicated by the uplink grant are unused. From an interference perspective it is preferable to avoid unnecessary transmission, for example the transmission of arbitrary bits.

Similarly, if the wireless device is pre-assigned a scheduling grant but does not have data of sufficiently high priority to transmit, it will currently also transmit padding in the uplink. This is a result from an LTE principle, that a wireless device, such as a terminal or user equipment (UE) shall always follow the uplink scheduling grants.

The cases wherein there is no data or no data with sufficiently high priority, are applicable to one carrier, either the PCell or a SCell, when using carrier aggregation.

Further there may also be other reasons why the wireless device determines not to use the resources indicated by an uplink grant. One further reason may be that the carrier to be used on the uplink for transmitting data, is not available for the reason that it is busy.

Applying carrier aggregation or dual connectivity to exploiting unlicensed spectrum, it is beneficial to determine whether resources indicated in the uplink scheduling grant may be used.

In order to determine whether a carrier is available, LBT may be applied.

It is noted that reasons for determining that resources are not used may comprise that no data is present to transmit using said resources, and that the carrier is busy, i.e. not available. A carrier may be busy due to other users/systems currently occupying resources. These reasons are not mutually exclusive. Worded differently, both reasons may exist at the same time. They are in this respect independent.

Transmitting 38 the information informing that first resources are unused may be made by using PUCCH, but may alternatively also be made using physical uplink shared channel (PUSCH). As mentioned above, preferably the PCell corresponding to a licensed spectrum may be used for this purpose. However, one or more SCells corresponding to unlicensed spectra are not excluded for this purpose. Using unlicensed spectra for this purpose, it must be recalled that transmission using an SCell will receive "best effort" quality.

In this text it is discussed whether to use the first resources indicated by an uplink scheduling grant.

The first resources are thus resources to be used by the wireless device for data transmission, for instance using the PUSCH. In order to transmit the information informing the radio network node that the first resources are unused, the wireless device needs resources for this transmission. These resources needed for the transmission of the information informing that the first resources are unused, are herein denoted second resources. These second resources may be one or more of the following: preconfigured in the wireless device, determined based on the first resources indicated in the uplink scheduling grant, signalled in the uplink scheduling grant, and derived from downlink control signalling resources carrying the uplink scheduling grant. Combinations of these ways to determine the second resource required for feedback transmission of the information informing that first resources are unused, are also envisaged herein.

For instance, in the case of multiple SCells, the identity of the SCell may be derived from a carrier indicator field in the uplink scheduling grant. This identity is preferably used when computing which PUCCH resources to be used for the transmission of the information informing that the first resources are unused. For example, the PUCCH resource may be a function of both an SCell resource indicated by the uplink grant, and the carrier indicator, indicating an identity of a SCell, which may be a different SCell, from the one as indicated by the uplink grant.

In the case of so-called semi-persistent scheduling where a radio network provides a wireless device with uplink scheduling grants for multiple subframes according to a preconfigured time periodicity, the wireless device may transmit information, on for instance PUCCH, whenever resources as indicated by the uplink grant of the semi-persistent scheduling , to the radio network node. These uplink scheduling grants may indicate resources on either PCell or SCell, in case of carrier aggregation. In principle, this information could however be transmitted on any uplink carrier; corresponding to either PCell or SCell. The second resource to be used in the uplink may be computed in the same way as outlined above.

Figure 4 presents a flow chart of a method in a radio network node 32 for communication with a wireless device 30, according to embodiments of the exemplary embodiments. The method comprises transmitting 42 to the wireless device 30 an uplink grant indicating first resources. The method also comprises receiving 44 from the wireless device 30 information informing that the first resources indicated by the uplink grant are unused.

Transmitting 34, 42 the uplink grant within the method of the radio network node 32 may comprise transmitting the uplink grant on a first carrier of a licensed spectrum, the uplink grant indicating the first resources on a second carrier of an unlicensed spectrum, and receiving 38, 44 on the first carrier the information informing that the first resources indicated by the uplink grant are unused.

Transmitting 34, 42 the uplink grant within the method of the radio network node 32 may comprise transmitting 34, 42 the uplink grant on the first carrier that corresponds to a PCell, where the uplink grant indicates the first resources on the second carrier that corresponds to a SCell.

The method in the radio network node 32 may comprise receiving 38, 44 on second resources the information indicating that the first resources are unused, wherein the second resources are one or more of the following: preconfigured, determined based on the first resources indicated in the uplink grant, signalled in the uplink grant, and derived from downlink control signalling resources carrying the uplink grant.

Receiving the information informing that the first resources are unused may comprise receiving 38,

44 the information informing that the first resources are unused, in a subframe in which the uplink grant indicates the first resources.

Figure 5 presents a flow chart of a method in a wireless device 30 for communicating with a radio network node 32, according to embodiments of the exemplary embodiments. The method comprises receiving 52 from the radio network node 32 an uplink grant indicating first resources. Also, the method in the wireless device comprises determining 54 whether to use the first resources indicated by the uplink grant. In addition, the method in the wireless device comprises, when determining that the first resources indicated by the uplink grant are unused, transmitting 56 to the radio network node 32 information informing that the first resources are unused.

Determining 36 by wireless device whether to use the first resources indicated by the uplink grant, may comprise determining not to use the first resources indicated by the uplink grant, when there is no data to transmit to the radio network node 32 on the first resources. This may be due that there is no data with sufficiently high priority to be transmitted in the uplink.

The method in the wireless device may comprise incrementing a counter when the first resources indicated by the uplink grant are unused. This counter may be a statistics counter. By incrementing the counter each time the first resources indicated by the uplink grant are unused, statistics about when the first resources are unused may be collected.

Transmitting information in the method in the wireless device may comprise transmitting information about the counter to the radio network node 32, upon request from the radio network node 32, or when the counter has exceeded a counter threshold. For instance, having detected that the counter has exceeded a number N, being the counter threshold, the wireless device may transmit information to the radio network node 32 about the counter.

By using a counter, the wireless device may report a fraction of uplink grants for which resources are not used, in a given time window, for instance reporting x out of y uplink grants not used for transmission. Statistics on the usage of uplink grants may be transmitted on a PCell, or on a SCell.

Statistics transmission on the PCell is preferable, as part of the PUSCH, for instance in a bit-field, or on the PUCCH.

Information informing the radio network node about statistics may be transmitted upon request from the eNodeB, or when a certain condition is met, for instance when a counter has exceeded a counter threshold.

The method in the wireless device may further comprise receiving 34, 52 the uplink grant on a first carrier of a licensed spectrum, the uplink grant indicating the first resources on a second carrier of an unlicensed spectrum, and transmitting 38, 56 on the first carrier the information informing that the first resources are unused.

The method in the wireless device may further comprise receiving 34, 52 the uplink grant on the first carrier corresponding to a PCell and that the uplink grant indicates the first resources on a second carrier corresponding to a SCell.

Transmitting the information indicating that the first resources are unused, in the method in the wireless device, may comprise transmitting the information indicating that the first resources are unused, on second resources, wherein the second resources are one or more of the following: preconfigured, determined based on the first resources indicated in the uplink grant, signalled in the uplink grant, and derived from downlink control signalling resources carrying the uplink grant. Transmitting the information indicating that the first resources are unused, in the method in the wireless device, may comprise transmitting, the information informing that the first resources are unused, in a subframe in which the uplink grant indicates the first resources.

Figure 6 schematically presents a radio network node 60 for a communicating with a wireless device. The radio network node 60 comprises a receiver 62, a transmitter 64, and a processing unit 66. The processing unit is adapted to transmit 34, 42 to the wireless device 30 via the transmitter 64 an uplink grant indicating first resources. The processing unit is further adapted to receive 38, 44 from the wireless device 30 via the receiver 62 information informing that the first resources indicated by the uplink grant are unused.

The processing unit 66 of the radio network node 60 may comprise a processor and a memory and wherein said memory contains instructions executable by said processor.

The processing unit 66 of the radio network node 60 may be adapted to transmit 34, 42 via the transmitter the uplink grant on a first carrier of a licensed spectrum, wherein the uplink grant indicates the first resources on a second carrier of an unlicensed spectrum, and to receive 38, 44 via the receiver 62 on the first carrier the information informing that the first resources indicated by the uplink grant are unused.

The first carrier within the radio network 60 node may correspond to a PCell and wherein the second carrier corresponds to a SCell.

The processing unit 66 of the radio network node 60 may further be adapted to receive 38, 44 on second resources the information indicating that the first resources are unused, wherein the second resources are one or more of the following: preconfigured, determined based on the first resources indicated in the uplink grant, signalled in the uplink grant, and derived from downlink control signalling resources carrying the uplink grant.

Processing unit 66 of the radio network node 60 may further be adapted to receive 38, 44 via the receiver 62 the information informing that the first resources are unused, in a subframe in which the uplink grant indicates the first resources.

The radio network node 60 may receive information informing that first resources are unused. This information may be used to affect further behaviour of the radio network node; examples being scheduling of resources, as well as radio resource management (RRM) for regulation of transmission power.

The radio network node may comprise an eNodeB.

Figure 7 schematically presents a radio network node 60 for a communicating with a wireless device. The radio network node 60 comprises transmitting means 72 adapted to transmit 34, 42 to the wireless device 30 an uplink grant indicating first resources. The radio network node 60 also comprises receiving means 74 adapted to receive 38, 44 from the wireless device 62 information informing that the first resources indicated by the uplink grant are unused. Figure 8 schematically presents a wireless device 80 for a communicating with a radio network 32, 60, 70 node. The wireless device 80 comprises a receiver 82, a transmitter 84, and a processing unit 86. The processing unit 86 is adapted to receive 34, 52 from the radio network node 32, 60, 70 via the receiver 82 an uplink grant indicating first resources. The processing unit 86 is adapted to determine 36, 54 whether to use the first resources indicated by the uplink grant. In addition, the processing unit 86 is also adapted to, when determining that the first resources indicated by the uplink grant are unused, transmit 38, 56 to the radio network node 32, 60, 70 via the transmitter 84 information informing that the first resources are unused.

The processing unit 86 of the wireless device 80 may comprise a processor and a memory and wherein said memory contains instructions executable by said processor.

The processing unit 86 of the wireless device may be adapted to determine not to use the first resources indicated by the uplink grant, when there is no data to transmit to the radio network node 32, 60, 70 on the first resources.

The processing unit 86 of the wireless device 80 may further be adapted to increment a counter when the first resources indicated by the uplink grant are unused.

The processing unit 86 of the wireless device 80 may further be adapted to transmit 56 via the transmitter 84 information about the counter, to the radio network node 32, 60, 70, upon request from the radio network node 32, 60, 70, or when the counter has exceeded a counter threshold.

The processing unit 86 of the wireless device 80 may further be adapted to receive 34, 52 via the receiver 82 the uplink grant on a first carrier of a licensed spectrum, where the uplink grant indicates the first resources on a second carrier of an unlicensed spectrum, and wherein the processing unit 86 further is adapted to transmit 38, 56 via the transmitter 84 on the first carrier the information informing that the first resources are unused.

The first carrier within the wireless device may correspond to a PCell and the second carrier may correspond to a SCell.

The processing unit 86 of the wireless device 80 may further be adapted to transmit 38, 56 via the transmitter 84 on second resources the information indicating that the first resources are unused, wherein the second resources are one or more of the following: preconfigured, determined based on the first resources indicated in the uplink grant, signalled in the uplink grant, and derived from downlink control signalling resources carrying the uplink grant.

The processing unit 86 of the wireless device 80 may further be adapted to transmit 38, 56 via the transmitter 84 the information informing that the first resources are unused, in a subframe in which the uplink grant indicates the first resources.

The wireless device may comprise a UE.

Figure 9 schematically presents a wireless device 90 for a communicating with a radio network node 32, 60, 70. The wireless device 90 comprises receiving means 92 adapted to receive 34, 52 from the radio network node 32, 60, 70 via the receiver 82 an uplink grant indicating first resources. The wireless device also comprises determining means 94 adapted to determine 36, 54 whether to use the first resources indicated by the uplink grant. The wireless device moreover also comprises transmitting means 96 adapted to transmit 38, 56 to the radio network node 32, 60, 70 via the transmitter 84 information informing that the first resources are unused, when determining that the first resources indicated by the uplink grant are unused.

The processing circuitry 914 of the server node 910 may comprise a processor and a memory and wherein said memory contains instructions executable by said processor.

Embodiments of the present exemplary embodiments have the following advantages:

It may be further noted that the above described embodiments are only given as examples and should not be limiting to the present exemplary embodiments, since other solutions, uses, objectives, and functions are apparent within the scope of the embodiments as claimed in the accompanying patent claims.

ABBREVIATIONS

(E)PDCCH (enhanced)physical downlink control channel

FDD frequency division duplex

LBT listen before talk

LTE long term evolution

PCell primary cell

PUCCH physical uplink control channel

PUSCH physical uplink shared channel

SCell secondary cell

TDD time division duplex UE user equipment

Claims

A method in a wireless device (30, 80, 90) for communicating with a radio network node (32, 60, 70), the method comprising:

receiving (34, 52) from the radio network node (32, 60, 70) an uplink grant indicating first resources;

determining (36, 54) whether to use the first resources indicated by the uplink grant; and when determining that the first resources indicated by the uplink grant are unused, transmitting (38, 56) to the radio network node (32, 60, 70) information informing that the first resources are unused.

The method according to claim 1, wherein determining (36, 54) whether to use the first resources indicated by the uplink grant, comprises determining not to use the first resources indicated by the uplink grant, when there is no data to transmit to the radio network node (32, 60, 70) on the first resources.

The method according to claim 1 or 2, further comprising incrementing a counter when the first resources indicated by the uplink grant are unused.

The method according to claim 3, further comprising transmitting information about the counter to the radio network node (32, 60, 70), upon request from the radio network node, or when the counter has exceeded a counter threshold.

The method according to any of claims 1 to 4, comprising receiving (34, 52) the uplink grant on a first carrier of a licensed spectrum, the uplink grant indicating the first resources on a second carrier of an unlicensed spectrum, and transmitting (38, 56) on the first carrier the information informing that the first resources are unused.

The method according to claim 5, comprising receiving (34, 52) the uplink grant on the first carrier corresponding to a primary cell, PCell, and the uplink grant indicating the first resources on a second carrier corresponding to a secondary cell, SCell.

The method according to any of the preceding claims, comprising transmitting (38, 56) on second resources the information indicating that the first resources are unused, wherein the second resources are one or more of the following: preconfigured, determined based on the first resources indicated in the uplink grant, signalled in the uplink grant, and derived from downlink control signalling resources carrying the uplink grant.

8. The method according to any of the preceding claims, comprising transmitting (38, 56) the information informing that the first resources are unused, in a subframe in which the uplink grant indicates the first resources.

9. A method in a radio network node (32, 60, 70) for communicating with a wireless device (30, 80, 90), the method comprising:

transmitting (34, 42) to the wireless device (30, 80, 90) an uplink grant indicating first resources; and

- receiving (38, 44) from the wireless device (30, 80, 90) information informing that the first resources indicated by the uplink grant are unused.

10. The method according to claim 9, comprising transmitting (34, 42) the uplink grant on a first

carrier of a licensed spectrum, the uplink grant indicating the first resources on a second carrier of an unlicensed spectrum, and receiving (38, 44) on the first carrier the information informing that the first resources indicated by the uplink grant are unused.

1 1. The method according to claim 10, comprising transmitting (34, 42) the uplink grant on the first carrier corresponding to a primary cell, PCell, and the uplink grant indicating the first resources on the second carrier corresponding to a secondary cell, SCell.

12. The method according to any of claims 9 to 1 1, comprising receiving (38, 44) on second resources the information indicating that the first resources are unused, wherein the second resources are one or more of the following: preconfigured, determined based on the first resources indicated in the uplink grant, signalled in the uplink grant, and derived from downlink control signalling resources carrying the uplink grant.

13. The method according to any of claims 9 to 12, comprising receiving (38, 44) the information informing that the first resources are unused, in a subframe in which the uplink grant indicates the first resources.

14. A wireless device (80) adapted to communicate with a radio network node (32, 60, 70), the

wireless device (80) comprises a receiver (82), a transmitter (84), and a processing unit (86), wherein the processing unit (86) is adapted to:

- receive (34, 52) via the receiver (82) from the radio network node (32, 60, 70) an uplink grant indicating first resources; determine (36, 54) whether to use the first resources indicated by the uplink grant; and transmit (38, 56) via the transmitter (84) to the radio network node (32, 60, 70) information informing that the first resources are unused, when the processing unit (86) has determined that the first resources indicated by the uplink grant are unused.

15. The wireless device (80) according to claim 14, wherein the processing unit (86) further is adapted to determine not to use the first resources indicated by the uplink grant, when there is no data to transmit to the radio network node (32, 60, 70) on the first resources.

16. The wireless device (80) according to claim 14 or 15, wherein the processing unit (86) further is adapted to increment a counter when the first resources indicated by the uplink grant are unused.

17. The wireless device (80) according to claim 16, wherein the processing unit (86) further is adapted to transmit (38, 56) via the transmitter (84) information about the counter, to the radio network node (32, 60, 70), upon request from the radio network node (32, 60, 70), or when the counter has exceeded a counter threshold.

18. The wireless device (80) according to any of claims 14 to 17, wherein the processing unit (86) further is adapted to receive (34, 52) via the receiver (82) the uplink grant on a first carrier of a licensed spectrum, where the uplink grant indicates the first resources on a second carrier of an unlicensed spectrum, and wherein the processing unit (86) further is adapted to transmit (38, 56) via the transmitter (84) on the first carrier the information informing that the first resources are unused.

19. The wireless device (80) according to claim 18, wherein the first carrier corresponds to a primary cell, PCell, and the second carrier corresponds to a secondary cell, SCell.

20. The wireless device (80) according to any of claims 14 to 19, wherein the processing unit (86) further is adapted to transmit (38, 56) via the transmitter (84) on second resources the information indicating that the first resources are unused, wherein the second resources are one or more of the following: preconfigured, determined based on the first resources indicated in the uplink grant, signalled in the uplink grant, and derived from downlink control signalling resources carrying the uplink grant.

21. The wireless device (80) according to any of claims 14 to 20, wherein the processing unit (86) further is adapted to transmit (38, 56) via the transmitter (84) the information informing that the first resources are unused, in a subframe in which the uplink grant indicates the first resources. 22. A radio network node (60) for communicating with a wireless device (30, 80, 90), said radio

network node (60) comprising a receiver (62), a transmitter (64), and a processing unit (66), wherein the processing unit is adapted to:

transmit (34, 42) via the transmitter (64) an uplink grant indicating first resources to the wireless device (30, 80, 90); and

- receive (38, 44) via the receiver (62) information informing that the first resources

indicated by the uplink grant are unused, from the wireless device (30, 80, 90).

The radio network node (60) according to claim 22, wherein the processing unit (66) is adapted to transmit (34, 42) via the transmitter (64) the uplink grant on a first carrier of a licensed spectrum, where the uplink grant indicates the first resources on a second carrier of an unlicensed spectrum, and wherein the processing unit (66) further is adapted to receive (38, 44) via the receiver (62) on the first carrier the information informing that the first resources indicated by the uplink grant are unused. 24. The radio network node (60) according to claim 23, wherein the first carrier corresponds to a

primary cell, PCell, and wherein the second carrier corresponds to a secondary cell, SCell.

25. The radio network node (60) according to any of claims 22 to 24, wherein the processing unit (66) further is adapted to receive (38, 44) on second resources the information indicating that the first resources are unused, wherein the second resources are one or more of the following:

preconfigured, determined based on the first resources indicated in the uplink grant, signalled in the uplink grant, and derived from downlink control signalling resources carrying the uplink grant.

26. The radio network node (60) according to any of claims 22 to 25, wherein the processing unit (66) further is adapted to receive (38, 44) via the receiver (62) the information informing that the first resources are unused, in a subframe in which the uplink grant indicates the first resources.