WO2018190757A1

WO2018190757A1 - Transmission scheduling in a wireless communication system

Info

Publication number: WO2018190757A1
Application number: PCT/SE2017/050373
Authority: WO
Inventors: Johan ZHANG; Ying Sun; Jianwei Zhang
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2017-04-12
Filing date: 2017-04-12
Publication date: 2018-10-18

Abstract

A radio network node (12B) is configured for use in a wireless communication system. The radio network node (12B) in particular is configured to, after a change in channel conditions based on which a first transmission (16A) was scheduled for a first user equipment to occur on a radio resource (18) over a scheduled period (20), schedule a second transmission (16B) for a second user equipment to occur on the radio resource (18) over at least a portion of the scheduled period (20). The radio network node (12B) is also configured to transmit or receive the second transmission (16B) as scheduled.

Description

TRANSMISSION SCHEDULING IN A WIRELESS COMMUNICATION SYSTEM

TECHNICAL FIELD

The application relates generally to a wireless communication system, and particularly to scheduling a transmission in such a wireless communication system.

BACKGROUND

The time period over which a transmission is performed in a wireless communication system (i.e., the transmission time interval, TTI) affects the receiver's ability to successfully receive and decode that transmission. The longer the TTI, the more the receiver is able to collect energy from the transmission in the face of noise and interference on the radio channel, and the greater the ability of the receiver to successfully decode the transmission. The TTI therefore may be set to appropriately account for the channel conditions expected for a transmission. A relatively shorter TTI (e.g., 1 ms) may suffice in fairly good channel conditions so as to advantageously minimize transmission latency, but a relatively longer TTI (e.g., 5000ms) may be required in poor channel conditions. Wreless technologies such as Narrowband Internet of Things (NB-loT) and enhanced machine type communication (eMTC) indeed allow long TTIs in order to enhance coverage under potentially poor channel conditions.

While increasing transmission time may improve coverage, that increase introduces challenges to scheduling transmissions in a way that optimizes radio resource usage. This proves true especially when channel conditions fluctuate rapidly.

SUMMARY

A transmission may be scheduled to occur on a certain radio resource over a certain time period, based on certain measurements or expectations about the channel conditions over which the transmission will be sent. Those channel conditions based on which the transmission was scheduled may change, though, even before the end of the time period over which the transmission is scheduled to occur. This may be the case for instance if the channel coherence time is shorter than the scheduled period, which is more likely for a relatively long (e.g., >10ms) scheduled period. Such a change in channel conditions impacts the receiver's ability to receive the transmission, for better or for worse. One or more embodiments herein advantageously account for a change in the channel conditions based on which a transmission was scheduled. Some embodiments for example schedule another transmission to occur on the same radio resource over at least a portion of the same time period, e.g., based on an understanding that decoding of the previously scheduled transmission will fail or succeed early due to the channel condition change. In one or more embodiments, this scheduling approach advantageously optimizes or improves radio resource usage. More particularly, embodiments herein include a method performed by a radio network node configured for use in a wireless communication system. The method comprises, after a change in channel conditions based on which a first transmission was scheduled for a first user equipment to occur on a radio resource over a scheduled period, scheduling a second transmission for a second user equipment to occur on the radio resource over at least a portion of the scheduled period. The method also comprises transmitting or receiving the second transmission as scheduled.

In some embodiments, the change in the channel conditions is indicative that decoding of the first transmission will fail, or is indicative that early decoding of the first transmission will succeed before the end of the scheduled period.

In some embodiments, the scheduling of the second transmission is performed after the channel conditions change by a certain extent.

Alternatively or additionally, the method may further comprises determining whether or not the channel conditions based on which the first transmission was scheduled have changed. In this case, the scheduling of the second transmission may be performed after determining that the channel conditions based on which the first transmission was scheduled have changed.. In some embodiments, for example, the determining is performed at each of one or more predefined times within the scheduled period.

In some embodiments, the first and second transmissions are downlink transmissions to the first and second user equipments. In this case, the transmitting or receiving may comprise transmitting the second transmission over at least a portion of the scheduled period during which the first transmission is not transmitted as scheduled. Alternatively or additionally, the transmitting or receiving may comprise, before the end of the scheduled period, switching from transmitting the first transmission to transmitting the second transmission, such that the radio network node stops transmitting the first transmission earlier than scheduled without notifying the first user equipment.

Alternatively, the first and second transmissions are uplink transmissions in other embodiments. In this case, the transmitting or receiving may comprise receiving the second transmission over at least a portion of the scheduled period during which the first transmission is also being transmitted as scheduled. Alternatively or additionally, the transmitting or receiving may comprise, before the end of the scheduled period, switching from decoding the first transmission to decoding the second transmission, such that the radio network node stops decoding the first transmission earlier than scheduled even though the first transmission is still transmitted over the scheduled period as scheduled.

In any of these embodiments, the method may further comprises, for each of multiple candidate user equipments, evaluating channel conditions for a transmission to be scheduled for the candidate user equipment on the radio resource, assuming the first transmission is interference to that transmission, and selecting the second user equipment from the multiple candidate user equipments based on the evaluating.

In some embodiments, the method further comprises selecting the second user equipment to be a user equipment associated with a predicted signal to interference plus noise ratio, SINR, that is higher by at least a defined margin than an SINR associated with the first user equipment, wherein the predicted SINR includes a signal power associated with the first user equipment as interference.

In any of these embodiments, the wireless communication system may be a narrowband internet of things (NB-loT) system.

Embodiments herein also include a corresponding radio network node, computer program, and carrier of the computer program (e.g., computer-readable medium).

Still other embodiments herein include a method performed by a radio node configured for use in a wireless communication system. The method comprises detecting a change in channel conditions based on which a transmission was scheduled for a user equipment to occur over a scheduled period. The method also comprises, after detecting the change, stopping decoding of or transmitting of the transmission before the end of the scheduled period, e.g., even though the transmission remains scheduled over the scheduled period.

In some embodiments, the detected change is indicative that decoding of the

transmission will fail, or is indicative that early decoding of the transmission will succeed before the end of the scheduled period.

In some embodiments, the detecting comprises detecting that the channel conditions have changed by a certain extent.

In some embodiments, the method further comprises, at each of one or more predefined times within the scheduled period, detecting whether a change has occurred in the channel conditions based on which the transmission was scheduled.

In some embodiments, the stopping comprises stopping decoding of the transmission before the end of the scheduled period, even though the transmission remains scheduled over the scheduled period.

In some embodiments, the stopping comprises stopping transmitting of the transmission before the end of the scheduled period, even though the transmission remains scheduled over the scheduled period.

In some embodiments, the wireless communication system is a narrowband internet of things (NB-loT) system.

Embodiments herein also include a corresponding radio node, computer program, and carrier of the computer program (e.g., computer-readable medium). BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a block diagram of a wireless communication system that includes a radio network node and a user equipment according to some embodiments.

Figure 2 is a call flow diagram related to some embodiments concerning uplink transmissions.

Figure 3 is a call flow diagram related to some embodiments concerning downlink transmissions.

Figure 4 is a logic flow diagram of a method performed by a radio network node according to some embodiments.

Figure 5 is a logic flow diagram of a method performed by a radio network node according to other embodiments.

Figure 6 is a block diagram of a wireless communication system that includes a radio network node and a user equipment according to other embodiments.

Figure 7 is a call flow diagram related to some embodiments concerning downlink transmissions.

Figure 8 is a call flow diagram related to some embodiments concerning uplink transmissions.

Figure 9 is a logic flow diagram of a method performed by a radio node according to some embodiments.

Figure 10 is a block diagram of a non-continuous scheduled period according to some embodiments.

Figure 1 1A is a block diagram of a radio network node according to some embodiments. Figure 1 1 B is a block diagram of a radio network node according to other embodiments. Figure 12A is a block diagram of a radio node according to some embodiments.

Figure 12B is a block diagram of a radio node according to other embodiments.

Figure 13 is a block diagram of a radio network node according to some embodiments. Figure 14 is a block diagram of a user equipment according to some embodiments.

DETAILED DESCRIPTION

Figure 1 illustrates a wireless communication system 10 according to one or more embodiments. The system 10 may be for instance a narrowband loT (NB-loT) system or an enhanced machine type communication (eMTC) system. Regardless, the system 10 includes one or more radio network nodes (e.g., one or more enhanced Node Bs, eNBs), two of which are shown as radio network nodes 12A and 12B. The system 10 also includes multiple user equipment (e.g., NB-loT or eMTC devices), two of which are shown as user equipment 14A and 14B.

Radio network nodes control the use of radio resources for transmissions in the system 10 (e.g., within respective cells controlled by those radio network nodes). Radio network nodes control radio resource usage for transmissions by scheduling those transmissions to occur on certain radio resources over certain time periods. Radio resources may include for instance frequency resources, code resources, time resources, spatial resources, any combination thereof, or any other resource on which a radio transmission is performed. The time period over which a transmission is scheduled may be indicated or reflected by the radio resource on which the transmission is scheduled. For example, where a radio resource is a time-frequency resource such as a radio block (e.g., 12 subcarriers over a 1 ms subframe), the scheduled time period may be the duration of the resource.

Figure 1 more particularly shows that radio network node 12A or 12B schedules a first transmission 16A for a first user equipment 14A. The first transmission 16A may be an uplink transmission from the first user equipment 14A to radio network node 12A or 12B, may be a downlink transmission from radio network node 12A or 12B to the first user equipment 14A, or may be a sidelink transmission from the first user equipment 14A to another user equipment. No matter whether the first transmission 16A is uplink, downlink, or sidelink, the radio network node 12A or 12B schedules the first transmission 16A to occur on a certain radio resource 18 over a certain time period, referred to as scheduled period 20. Note in this regard that the left- hand axis of the graph in Figure 1 reflects the radio resource domain(s) that define which radio resource 18 is used by a transmission, and the bottom axis of the graph reflects the time domain over which a transmission is scheduled.

In some embodiments, the first transmission 16A is scheduled in this way based on certain measurements or expectations about the channel conditions over which the first transmission 16A will be sent. For example, the radio network node 12A or 12B may measure the channel conditions and/or receive measurement reports from the first user equipment 14A and/or another radio network node indicating the channel conditions. Based on those channel conditions, the radio network node 12A or 12B decides to schedule the first transmission 16A on the certain radio resource 18 over the scheduled period 20.

The length of the scheduled period 20 may be statically fixed, or may be dynamically adjusted by, governed by, or otherwise determined by the decision to schedule the first transmission 16A. For example, where the first transmission 16A constitutes the transmission of one or more repetitions of a data block (e.g., a medium access control (MAC) protocol data unit (PDU) or a transport block), the scheduling decision may involve determining how many repetitions are to be transmitted, which may in turn dictate the length of the scheduled period 20 (with a greater number of repetitions requiring a longer scheduled period 20).

Especially when the channel coherence time is shorter than the scheduled period 20 (which may be the case for instance for a large number of repetitions), the channel conditions based on which the first transmission 16A is scheduled may change before the scheduled period 20 ends. In some embodiments, for example, the radio network node 12A or 12B decides to schedule the first transmission 16 based on a measurement or expectation that the first transmission 16A will be sent over certain channel conditions, but those measured or expected channel conditions do not hold throughout the scheduled period 20. The channel conditions may for instance improve or deteriorate in the interim between the first transmission's scheduling decision and the end of the scheduled period 20 (e.g., such that the channel conditions based on which the first transmission 16A was scheduled end up being too optimistic or pessimistic). Figure 1 in this regard shows that the channel conditions 22A for the first transmission 16A deteriorate over the course of the scheduled period 20. Note in this regard that the right-hand axis of the graph in Figure 1 reflects the channel conditions that exist at a certain time.

One or more embodiments herein advantageously account for and exploit a change in the channel conditions based on which the first transmission 16A was scheduled, in order to schedule a second transmission 16B for a second user equipment 14B in the system 10. More particularly, after (e.g., responsive to) a change in the channel conditions 22A based on which the first transmission 16A was scheduled to occur on a radio resource 18 over the scheduled period 20, the radio network node 12B schedules a second transmission 16B for a second user equipment 14B. In fact, in some embodiments, the radio network node 12B schedules the second transmission 16B to occur on the same radio resource 18 over at least a portion of the same scheduling period 20. In one or more embodiments, this scheduling approach

advantageously optimizes or improves radio resource usage, e.g., by exploiting the radio resource 18 for the second transmission 16B during a portion of the scheduling period 20 in which use of the radio resource 18 for the first transmission 16A would have been unnecessary, wasteful, or non-optimal.

Figure 1 for example shows deterioration in the channel conditions 22A based on which the first transmission 16A was scheduled to occur over the scheduled period 20. After (e.g., responsive to) that deterioration, radio network node 12B schedules the second transmission 16B to occur on the same radio resource 18 over at least a portion 20B of the scheduling period 20, with the second transmission 16B potentially extending beyond the scheduling period 20 as well. As shown, for instance, the channel conditions 22A deteriorate by a certain extent over the course of a first portion 20A of the scheduling period 20 (e.g., deteriorate by at least a threshold TH, expressed for instance as a certain amount or percentage change). Even though the first transmission 16A has already been scheduled to occur on the radio resource 18 over the whole scheduling period 20, this deterioration in some embodiments prompts the radio network node 12B to schedule the second transmission 16B to occur on the radio resource 18 over the latter portion 20B of the scheduling period 20.

In some embodiments, the channel conditions 22A deteriorating in this way or to this extent is indicative that decoding of the first transmission 16A will fail, e.g., at least with a certain degree of likelihood. In this and other embodiments, therefore, the radio network node 12B's scheduling of the second transmission 16B on the same radio resource 18 and over at least a portion of the same scheduled period 20 as the first transmission 16A may amount to or be done as part of a decision to effectively "give up" on the first transmission 16A. Having given up on the first transmission 16A, the radio network node 12B does not concern itself with what effect, if any, the scheduling and transmission of the second transmission 16B on the same radio resource 18 may have on decoding of the first transmission 16A.

Similarly, although not shown in Figure 1 , the channel conditions 22A based on which the first transmission 16A was scheduled may improve, e.g., by a certain extent. After (e.g., responsive to) this improvement, the radio network node 12B may schedule the second transmission 16B in a similar way to that described above with respect to channel condition deterioration; that is, to occur on the same radio resource 18 over at least a portion 20B of the scheduling period 20. The radio network node 12B may do so based on an understanding or prediction that the channel conditions 22A improving in this way or to this extent is indicative that decoding of the first transmission 16A will succeed earlier than scheduled, e.g., at least with a certain degree of likelihood. The radio network node 12B may for instance schedule the second transmission 16B to occur on the radio resource 18 within the scheduled period 20, but to occur after the first transmission 16A has been or is expected to be decoded early. With the first transmission 16A being or expected to be decoded by the time the second transmission 16B is transmitted on the radio resource 18, the radio network node 12B does not concern itself with what effect, if any, the scheduling and transmission of the second transmission 16B on the same radio resource 18 may have on decoding of the first transmission 16A.

Where the first and second transmissions 16A, 16B are uplink transmissions, for example, the radio network node 12B may not concern itself with additional interference that it may introduce to the first transmission 16A by its scheduling of the second transmission 16B on the same radio resource 18. In fact, the radio network node 12A or 12B may even stop decoding the first transmission 16A earlier than scheduled, even though the first transmission 16A continues to be transmitted as scheduled, either because decoding of the first transmission 16A will ultimately fail or because decoding of the first transmission 16A has already succeeded. That is, the radio network node 12A or 12B in some embodiments does not cancel the previous scheduling of the first transmission 16A, such that the first and second transmissions 16A, 16B are co-scheduled on the radio resource 16 for at least a portion 20B of the scheduled period 20. The radio network node 12A or 12B may not even notify the first user equipment 14A that it has given up on or has already successfully decoded the first transmission 16A before the end of the scheduled period 20. Indeed, downlink channel conditions may not be good enough to timely and efficiently transmit such a notification to the first user equipment 14A. In these and other embodiments, therefore, the first user equipment 14A may still transmit the first transmission 16A over the portion 20B of the scheduled period 20, even after channel conditions 22A have deteriorated or improved. In this case, the radio network node 12A or 12B, before the end of the scheduled period 20, may simply stop decoding the first transmission 16A, such that it stops decoding the first transmission 16A early even though the first transmission 16A is still transmitted over the scheduled period 20 as scheduled. Where the radio network node 12B is the radio network node that decodes the first transmission 16A, this may mean that the radio network node 12B switches from decoding the first transmission 16A to decoding the second transmission 16B.

Analogously, where the first and second transmissions 16A, 16B are downlink transmissions, the radio network node 12A or 12B may stop transmitting the first transmission 16A earlier than scheduled, in favor of "re-using" the radio resource 18 for transmitting the second transmission 16B instead. Indeed, having given up on the first transmission 16A or having determined that the first user equipment 14A will be able to decode the first transmission 16A early, the radio network node 12A or 12B may stop transmitting the first transmission 16A based on an understanding that doing so will not actually affect the first user equipment's ability to ultimately decode the first transmission 16A. The radio network node 12A or 12B in some embodiments may not even notify the first user equipment 14A that it stops transmitting the first transmission 16A early. Indeed, downlink channel conditions may not be good enough to timely and efficiently transmit such a notification to the first user equipment 14A. In these and other embodiments, therefore, the first user equipment 14A may still attempt to decode the first transmission 16A over the portion 20B of the scheduled period 20, even though the first transmission 16A is not actually being transmitted anymore due to channel conditions 22A having deteriorated or improved. In this case, the radio network node 12A or 12B, before the end of the scheduled period 20, may simply stop transmitting the first transmission 16A, such that it stops transmitting the first transmission 16A early even though the first user equipment 1614A still expects the first transmission 16A over the scheduled period 20. Where the radio network node 12B is the radio network node that transmits the first transmission 16A, this may mean that the radio network node 12B switches from transmitting the first transmission 16A to transmitting the second transmission 16B.

Figure 2 illustrates additional details of one or more embodiments where the first and second transmissions 16A, 16B are uplink transmissions. As shown, radio network node 12A or 12B determines uplink channel conditions 22A for the first user equipment 14A in the form of a signal to noise plus interference ratio (SINR) for the first user equipment 14A (Step S1). The radio network node 12A or 12B may for instance receive an uplink (UL) reference signal transmitted by the first user equipment 14A and measure the SINR of the UL reference signal. Regardless, based on the determined uplink channel conditions 22A, the radio network node 12A or 12B decides to schedule the first transmission 16A to occur over the scheduled period 20 and transmits an uplink grant to the first user equipment 14A indicating such scheduling (Step S2). During the scheduled period 20, the first user equipment 14A may transmit a portion of the first transmission 16A (e.g., one or more repetitions of the first transmission 16A) and the radio network node 12A or 12B may decode that portion of the first transmission 16A (Step S3). As shown, though, the radio network node 12A or 12B may later determine the uplink channel conditions 22A for the first user equipment 14A again, such as by measuring another UL reference signal from the first user equipment 14A during the scheduled period 20 (Step S4). Based on this, the radio network node 12A or 12B may detect that the channel conditions 22A based on which the first transmission 16A was scheduled have changed (e.g., increased by at least a threshold TH1 or decreased by at least a threshold TH2, which may each be specified as a certain amount or percentage change) (Step S5). Alternatively or additionally, the radio network node 12A or 12B may indirectly detect that the channel conditions 22A based on which the first transmission 16A was scheduled have changed (e.g., improved), by detecting that the first transmission 16A was decoded early, e.g., before the end of the scheduled period 20 or before receiving all repetitions of the first transmission 16A. Either way, after (e.g., responsive to) detection of such a change, the radio network node 12B decides to schedule the second transmission 16B to occur on the same radio resource 18 over at least a portion 20B of the scheduled period 20 and transmits an uplink grant to the second user equipment 14B indicating such scheduling (Step S6).

The radio network node 12A or 12B may also stop decoding subsequent portions of the first transmission 16A, even though the first transmission 16A continues to be transmitted (Steps S7 and S9). The radio network node 12A or 12B may do this either because it has already successfully decoded the first transmission 16A early (e.g., due to improved channel conditions 22A) or because it has given up on being able to successfully decode the first transmission 16A (e.g., due to deteriorated channel conditions 22A). Meanwhile, the second user equipment 14B transmits the second transmission 16B during a portion 20B of the scheduled period 20 and the radio network node 12B corresponding decodes (or at least attempts to decode) that second transmission 16B (Step S8).

Figure 3 analogously illustrates additional details of one or more embodiments where the first and second transmissions 16A, 16B are downlink transmissions. As shown, radio network node 12A or 12B determines downlink channel conditions 22A for the first user equipment 14A in the form of a signal to noise plus interference ratio (SINR) for the first user equipment 14A (Step S1). The radio network node 12A or 12B may for instance receive a downlink (DL) measurement report from the first user equipment 14A (e.g., a channel quality indication, CQI, report or a reference signal received power, RSRP, report) that was generated by the first user equipment 15A based on measurement of a downlink reference signal. Regardless, based on the determined downlink channel conditions 22A, the radio network node 12A or 12B decides to schedule the first transmission 16A to occur over the scheduled period 20 and transmits a downlink grant to the first user equipment 14A indicating such scheduling (Step S2). During the scheduled period 20, the radio network node 12A or 12B may transmit a portion of the first transmission 16A (e.g., one or more repetitions of the first transmission 16A) to the first user equipment 14A (Step S3). As shown, though, the radio network node 12A or 12B may later determine the downlink channel conditions 22A for the first user equipment 14A again, such as by receiving another DL measurement report from the first user equipment 14A during the scheduled period 20 (Step S4). Based on this, the radio network node 12A or 12B may detect that the channel conditions 22A based on which the first transmission 16A was scheduled have changed (e.g., increased by at least a threshold TH1 or decreased by at least a threshold TH2, which may each be specified as a certain amount or percentage change) (Step S5). After (e.g., responsive to) detection of such a change, the radio network node 12B decides to schedule the second transmission 16B to occur on the same radio resource 18 over at least a portion 20B of the scheduled period 20 and transmits a downlink grant to the second user equipment 14B indicating such scheduling (Step S6).

The radio network node 12A or 12B may also stop transmitting subsequent portions of the first transmission 16A, even though the first user equipment 14A continues to expect the first transmission 16A (Steps S7 and S9). The radio network node 12A or 12B may do this either because it determines that the first user equipment 14A will have already successfully decoded the first transmission 16A early (e.g., due to improved channel conditions 22A) or because it has given up on the first user equipment 14A being able to successfully decode the first

transmission 16A (e.g., due to deteriorated channel conditions 22A). Meanwhile, the radio network node 12B transmits the second transmission 16B to the second user equipment 14B during a portion 20B of the scheduled period 20 (Step S8).

The certain extent of change in the channel conditions 22A that may trigger or otherwise condition scheduling of the second transmission 16B in some embodiments may be set statically or may vary dynamically based on one or more criteria. For example, in some embodiments, one or more thresholds define the extent of change in the channel conditions 22A that is to trigger or condition the scheduling of the second transmission 16B. Each of these one or more thresholds may be statically set to trigger or condition the second transmissions' scheduling upon the channel conditions 22A having changed by a predefined amount or percentage as of a predefined time in the scheduled period 20. Accordingly, in some

embodiments, a determination as to whether the channel conditions 22A have changed may be performed (e.g., by the radio network node 12B) at each of one or more predefined times in the scheduled period 20. For example, one threshold may dictate that the second transmission 16B be scheduled if the channel conditions based on which the first transmission 16A was scheduled have changed by 3 dB as of a halfway point in the scheduled period 20 (i.e., as of 50% of the transmission time interval). Alternatively or additionally, another threshold may dictate that the second transmission 16B be scheduled if the channel conditions based on which the first transmission 16A was scheduled have changed by 6 dB as of a quarter point in the scheduled period 20 (i.e., as of 25% of the transmission time interval). In still other

embodiments, a threshold may be dynamically set to trigger or condition the second transmission's scheduling upon the channel conditions 22A having changed by different amounts or percentages as of different times in the scheduled period 20. For example, the threshold may be calculated to specify a certain amount or percentage as a function of a certain time in the scheduled period 20. Note though that different thresholds may be used for governing the second transmission's scheduling upon channel condition changes in different directions (i.e., one threshold TH 1 for channel condition improvement and a different threshold TH2 for channel conditions deterioration).

As suggested by Figures 2 and 3, the radio network node 12B that schedules the second transmission 16B in some embodiments itself may evaluate whether a change in the channel conditions 22A based on which the first transmission 16A was scheduled has occurred. The radio network node 12B may for instance compare the channel conditions 22A at different times, e.g., by comparing the channel conditions 22A based on which the first transmission 16A was scheduled to the channel conditions 22A as they exist during the scheduled period 20. The radio network node 12B may even perform some measurement (e.g., SINR measurement) which represents the channel conditions 22A or from which the channel conditions 22A are determined. In some embodiments, though, the radio network node 12B may alternatively or additionally receive information (e.g., pathloss information) from one or more other radio network nodes indicating the channel conditions 22A or from which the radio network node 12B determines the channel conditions 22A.

In other embodiments, a different radio network node (e.g., radio network node 12A) is the node that evaluates whether a change has occurred in the channel conditions 22A based on which the first transmission 16A was scheduled. For example, where the first transmission 16A is for a first user equipment 14A in a first cell, and the second transmission 16B is for a second user equipment 14B in a second cell, a radio network node serving the first cell may evaluate whether a change has occurred in the channel conditions 22A based on which the first transmission 16A was scheduled. Regardless, this different radio node may transmit signaling to the radio network node 12B indicating whether such a change has occurred, e.g., to a defined extent. That is, the different radio network node may obtain information indicating whether or an extent to which a change has occurred in the channel conditions 22A based on which the first transmission 16A was scheduled, and transmit the obtained information to the radio network node 12B. Based on or responsive to this signaling, the radio network node 12B may schedule the second transmission 16B.

In some embodiments as suggested above, it is the change in channel conditions 22A based on which the first transmission 16A was scheduled that triggers or prompts the radio network node 12B to schedule the second transmission 16B. For example, the radio network node 12B may decide to schedule a second transmission 16B (e.g., if possible or needed) responsive to detecting that such a change in the channel conditions 22A for the first transmission 16A has occurred. In these and other embodiments, therefore, the channel condition change for the first transmission 16A may prompt the radio network node 12B to evaluate for which of multiple candidate user equipments, if any, it is to schedule a transmission on the same radio resource 18 over at least a portion 20B of the scheduled period 20. Based on this evaluation, the radio network node 12B may select from among the candidate user equipments the second user equipment 14B for which to schedule a transmission as the second transmission 16B.

In one or more of these embodiments, the radio network node 12B may perform this selection by, for each of the candidate user equipments, evaluating the channel conditions for a transmission to be scheduled for that candidate user equipment on the radio resource 18. In some embodiments, the channel conditions for a transmission to be scheduled for a candidate user equipment may be evaluated under the assumption that the first transmission 16A is or would be interference to that transmission (e.g., if that candidate user equipment were to be selected and thereby "paired" with the first user equipment 14A). This may be the case for instance in embodiments where the second transmission 16B is scheduled on the radio resource 18 duration a potion 20B of the scheduled period 20, even though the first

transmission 16A is still transmitted during that portion 20B as scheduled. One example of such an embodiment is where the first and second transmissions 16A, 16B are uplink transmissions, and the first user equipment 14A is not notified that the first transmission 16A will fail or has been decoded early. In these and other embodiments, therefore, the radio network node 12B may broadly select a candidate user equipment that has better channel conditions than the first user equipment 14A.

As one specific example, the radio network node 12B may select the second user equipment 14B as being a user equipment associated with channel conditions that will support a transmission meeting certain criteria (e.g., related to quality of service), even in the face of interference from the first transmission 16A. One example criteria in this regard is that the selected user equipment is associated with a predicted SINR that is higher by at least a defined margin than an SINR associated with the first user equipment 14A, where the predicted SINR includes a signal power associated with the first user equipment 14A as interference. In uplink embodiments, this may translate into the selected user equipment having a predicted SINR at the radio network node 12B that is higher by at least a defined margin than the first user equipment's SINR at the radio network node 12A or 12B, where the predicted SINR includes the first user equipment's received signal power at the radio network node 12A or 12B as interference.

Regardless, where the selection is performed from among M candidate user equipments (UE), this may be expressed mathematically as, for i=0... M-1 , selecting candidate UE i if

101og₁₀ SINR_{UEillpredlcted} > SINR_UE + TH , where SINR_{UE{ predlcted} is the predicted SINR of candidate UE i, SINR_UE is the SINR of the first user equipment 14A, and TH is a threshold defining the margin by which the predicted SINR of candidate UE i must be higher than the SINR of the first user equipment 14A in order for the candidate UE i to be selected (TH may be set depending on a prediction of interference). Note that the predicted SINR of candidate UE i SINR_{UE i) predicted} includes a signal power associated with the first user equipment 14A P_UE as

P 0)

interference. SINR_{UE j) predicted} may for instance be expressed as ^-^-— , where P_UE{i) is a

P_JJE + N + 1

signal power associated with candidate UE i, and N + I is noise plus interference. In uplink embodiments, for instance, the signal power associated with the first user equipment 14A P_UE and the signal power associated with candidate UE i P_UE(i) may be received signal powers at the radio network node 12A or 12B. Regardless, one or both of these signal powers may be measured by the radio network node 12A or 12B, or may be determined or estimated based on measurement reports from the candidate UE i and the first user equipment 14A.

In other embodiments, by contrast, the scheduling of the second transmission 16B is triggered or prompted by a different triggering criteria, but the change in channel conditions 22A based on which the first transmission 16A was scheduled functions as a condition for the second transmission 16B to be scheduled on the same radio resource 18 and during at least a portion of the same scheduled period 20 as the first transmission 16A. For example, in some embodiments, the receipt of a scheduling request from the second user equipment 14B triggers the radio network node 12B to schedule the second transmission 16B, at which point the radio network node 12B evaluates on which radio resource and during which time period to schedule the second transmission 16B. As part of this evaluation, the radio network node 12B may determine (e.g., itself or based on received signaling) that a change has occurred in the channel conditions 22A based on which the first transmission 16A was scheduled to occur on the radio resource 18 over the scheduled period 20. Based on this determination, the radio network node 12B may decide to schedule the second transmission 16B on the same radio resource 18 for at least a portion 20B of the same scheduled period 20 as that over which the first transmission 16A is scheduled. In this case, therefore, the radio network node 12B may broadly engage in a search for which radio resource and/or which time period to schedule a transmission for a certain user equipment, as opposed to engaging in a search for a second user equipment 14B for which to schedule a transmission on a certain radio resource and time period.

In view of the above modifications and variations, Figure 4 generally illustrates a method

100 performed by a radio network node 12B according to one or more embodiments. As shown, the method 100 includes, after a change in channel conditions based on which a first transmission 16A was scheduled for a first user equipment 14A to occur on a radio resource 18 over a scheduled period 20, scheduling a second transmission 16B for a second user equipment 14B to occur on the radio resource 18 over at least a portion 20B of the scheduled period 20 (Block 102). The method also includes transmitting or receiving the second

transmission 16B as scheduled (Block 104).

As described above, the method 100 may further include determining whether or not the channel conditions based on which the first transmission 16A was scheduled have changed (Block 106). In some embodiments, this determination may be made based on at least some information received from another radio network node (e.g., radio network node 12A). This information may for instance indicate whether or an extent to which a change has occurred in channel conditions based on which the first transmission 16A was scheduled. In one or more of these embodiments, this is the case when the first and second transmissions 16A, 16B are scheduled in different cells.

Figure 5 in this regard illustrates a method 200 performed by a radio network node 12N configured to serve a first cell in some embodiments. As shown, the method 200 includes obtaining information indicating whether or an extent to which a change has occurred in channel conditions based on which a first transmission 16A was scheduled to occur in the first cell for a first user equipment 14A on a radio resource 18 over a scheduled period 20 (Block 202). The method 200 also includes transmitting the obtained information to a second radio network node 12B that is configured for serving a second cell (Block 204). The second radio network node 12B as described above may in turn schedule a second transmission 16B as described above in the second cell.

Embodiments described above exploit a change in channel conditions based on which the first transmission 16A was scheduled in order to schedule a second transmission 16B. Other embodiments herein exploit that change for other purposes, such as to avoid needlessly transmitting or decoding the first transmission 16A, even if no second transmission 16B is scheduled. This may for instance conserve power or processing resources, may improve the efficiency of radio resource usage, or may reduce interference in the system 10. Figure 6 illustrates one or more embodiments in this regard.

As shown in Figure 6, radio network node 12C schedules a transmission 16C for a user equipment 14C. The transmission 16C may again be an uplink transmission, a downlink transmission, or a sidelink transmission. Regardless, the transmission 16C is scheduled to occur over a scheduled period 20C, based on certain measurements or expectations about the channel conditions over which the transmission 16C will be sent. Similar to the above, though, those channel conditions may not hold throughout the scheduled period 20C. Figure 6 in this regard shows that the channel conditions 22C for the transmission 16C deteriorate over the course of the scheduled period 20C.

One or more embodiments herein advantageously account for and exploit a change in the channel conditions based on which the transmission 16C was scheduled, in order to stop transmitting or decoding the transmission 16C. More particularly, after a change (e.g., of a certain extent) in the channel conditions based on which the transmission 16C was scheduled to occur over the scheduled period 20C, decoding or transmitting of the transmission 16C is stopped, i.e., before the end of the scheduled period 20C. Decoding or transmitting may be stopped even though the transmission 16C remains scheduled to occur over the scheduled period 20C. Figure 6 for instance shows that the transmission 16C is transmitted or decoded during a first portion 20C-1 of the scheduled period 20C, but that transmission or decoding is stopped during a second portion 20C-2 of the scheduled period 20C after channel conditions 20C have changed, e.g., deteriorated by a threshold TH. Indeed, in some embodiments similar to those above, the channel conditions 20C changing in this way or to this extent is indicative that decoding of the transmission 16C will fail or will succeed early before the end of the scheduled period 20C. Accordingly, stopping decoding of or transmitting of the transmission 16C will not actually affect the ability of the transmission 16C to be decoded in this case.

Note that the radio network node 12C and/or the user equipment 14C may stop transmitting or decoding the transmission 16C in this way. This may be the case regardless of whether the transmission 16C is an uplink, downlink, or sidelink transmission.

Figure 7 nonetheless illustrates additional details of some embodiments where the transmission 16C is a downlink transmission and the user equipment 14C stops decoding the transmission 16C after detecting a change in the channel conditions based on which the transmission 16C was scheduled. As shown, The user equipment 14C measures downlink channel conditions in the form of SIN R based on a downlink (DL) reference signal received from the radio network node 12C (Steps S1-S2). The user equipment 14C sends a downlink measurement report (e.g., CQI or RSRP report) to the radio network node 12C based on the measured channel conditions (Step S3). The radio network node 12C in turn schedules the transmission 16C to be transmitted to the user equipment 14C, based on the SINR reflected by the downlink measurement report. The radio network node 12C in this regard transmits a downlink grant to the user equipment 14C scheduling the transmission 16C to occur in the scheduled period 20C (Step S4). During the scheduled period 20C, the radio network node 12C transmits a portion of the transmission 16C (e.g., one or more repetitions of the transmission 16C) and the user equipment 14C decodes that portion of the transmission 16C (Step S5).

As shown, though, the user equipment 14C may later determine the downlink channel conditions 22C again, such as by measuring another DL reference signal from the radio network node 12C during the scheduled period 20C (Steps S6-S7). Based on this, the user equipment 14C may detect that the channel conditions 22C based on which the transmission 16C was scheduled have changed (e.g., increased by at least a threshold TH1 or decreased by at least a threshold TH2, which may each be specified as a certain amount or percentage change) (Step S8). Alternatively or additionally, the user equipment 14C may indirectly detect that the channel conditions 22C based on which the transmission 16C was scheduled have changed (e.g., improved), by detecting that the transmission 16C was decoded early, e.g., before the end of the scheduled period 20C or before receiving all repetitions of the transmission 16C. Either way, after (e.g., responsive to) detection of such a change, the user equipment 14C stops decoding subsequent portions of the transmission 16C, even though the transmission 16C continues to be transmitted (Steps S9-S10) in cases where the user equipment 14C does not notify the radio network node 12C that it has stopped decoding. The user equipment 14C may do this either because it has already successfully decoded the transmission 16C early (e.g., due to improved channel conditions 22C) or because it has given up on being able to successfully decode the transmission 16C (e.g., due to deteriorated channel conditions 22C).

Figure 8 illustrates corresponding processing performed by the user equipment 14C in embodiments where the transmission 16C is a downlink transmission. As shown, the user equipment 14C determines uplink channel conditions in the form of uplink SINR (Step S1) and receives an uplink grant based on those channel conditions (Step S2). That uplink grant schedules the transmission 16C to occur during the scheduled period 20C. During the scheduled period 20C, the user equipment 14C transmits a portion of the transmission 16C (e.g., one or more repetitions of the transmission 16C) (Step S3).

As shown, though, the user equipment 14C may later determine the uplink channel conditions again (Step S4). Based on this, the user equipment 14C may detect that the channel conditions 22C based on which the transmission 16C was scheduled have changed (e.g., increased by at least a threshold TH1 or decreased by at least a threshold TH2, which may each be specified as a certain amount or percentage change) (Step S5). After (e.g., responsive to) detection of such a change, the user equipment 14C stops transmitting subsequent portions of the transmission 16C, even though the transmission 16C is still scheduled to be transmitted (Steps S6-S7) in cases where the user equipment 14C does not notify the radio network node 12C that it has stopped transmitting. The user equipment 14C may do this either because it predicts that the radio network node 12C will have already successfully decoded the

transmission 16C early (e.g., due to improved channel conditions 22C) or because it has given up on the radio network node 12C being able to successfully decode the transmission 16C (e.g., due to deteriorated channel conditions 22C).

In view of the above modifications and variations, Figure 9 generally illustrates a method 300 performed by a radio node (e.g., a radio network node or a user equipment) configured for use in a wireless communication system 10 according to some embodiments. As shown, the method 300 includes detecting a change in channel conditions based on which a transmission 16C was scheduled for a user equipment 14C to occur over a scheduled period 20C (Block 302). The method also includes, after detecting the change, stopping decoding of or transmitting of the transmission 16C before the end of the scheduled period 20C (Block 304). The decoding or transmitting of the transmission 16C may be stopped even though the transmission 14C remains scheduled over the scheduled period 20C.

Note that embodiments described above may be performed separately or in

combination. For example, in some embodiments, the radio network node 12B may attempt to schedule a second transmission 16B after channel conditions based on which a first transmission 16A was scheduled have changed. But, if that attempt fails, such as may be the case for instance if no candidate user equipment is suitable for selecting as the second user equipment 14B, the radio network node 12B may nonetheless still stop decoding or transmitting the first transmission 16A (e.g., in order to save power).

Note also that embodiments described above may be performed selectively with respect to certain transmissions, such as transmissions deemed higher priority than other transmissions for which the embodiments are not performed. The second transmission 16C described above for example may be a higher priority transmission (e.g., a delay critical transmission) than the first transmission 16A. In this way, some embodiments schedule a delay critical transmission associated with good channel conditions on a radio resource 18 without waiting for another transmission (e.g., with a long transmission time) on that radio resource 18 to no longer be scheduled on that resource.

In these and other embodiments, therefore, such scheduling may improve latency performance in a scenario with relatively high load and transmissions with different priorities and/or transmission lengths. Alternatively or additionally, some embodiments reduce interference in the system (e.g., inter-cell interference), such as by avoiding the needless transmission of a transmission that has already been decoded or whose decoding will ultimately fail. This may translate into higher system throughput.

Still further, some embodiments as described herein exploit scheduling parameters exchanged between radio network nodes. Such scheduling parameters may directly or indirectly indicate for instance channel conditions for, changes in channel conditions for, and/or the priority (e.g., high or low) of scheduled transmissions or transmissions to be scheduled.

Note also that, while the figures illustrate a scheduled period 20, 20C that is continuous in time, the scheduled period 20, 20C may be continuous or non-continuous in time. For example, a scheduled period in some embodiments may be a non-continuous period of time during which a transmission is scheduled to occur (e.g., according to a single scheduling decision of a radio network node), excluding one or more gaps in the transmission during which the transmission is not to be transmitted. The one or more transmission gaps do not constitute part of the scheduled period in this case. Figure 10 illustrates one example in this regard when the scheduled period 20 or 20C is non-continuous in time.

As shown in Figure 10, a transmission 16D is scheduled to occur over a non-continuous scheduled period 20D. This non-continuous scheduled period 20D includes time intervals 20D-1 , 20D-2, and 20D-3 that are separated by transmission gaps 30. The transmission 16D is scheduled to occur during these time intervals 20D-1 , 20D-2, and 20D-3, but not during the transmission gaps 30.

A radio network node may for instance schedule the transmission 16D to occur over a certain number of subframes. But the transmission 16D may be performed with transmission gaps 30 therein. For example, it may be predefined that after transmission of a certain number of time units, a gap of a certain duration shall be inserted, during which the transmission 16D is postponed. Alternatively, a radio network node may configure (e.g., via higher layer signaling such as radio resource control signaling) that transmission gaps are to occur with a certain periodicity and duration. Regardless, the transmission 16D is postponed during a transmission gap 30 and continues/resumes after the transmission gap 30. Where the transmission 16D is scheduled based on a scheduling request or scheduling grant, the transmission 16D may resume after a transmission gap 30 without another scheduling request or scheduling grant prompting that resumption. In this case, the non-continuous scheduled period 20D may result from a single scheduling decision that the transmission 16D is to have a certain transmission length (e.g., a certain number of subframes) and from one transmission gaps of a transmission gap pattern temporarily interrupting that transmission 16D.

Note further that, in some embodiments, the transmission 16D may comprise multiple repetitions of a data block (e.g., a transport block), including the original transmission of that data block. When such a transmission 16D is scheduled to occur over a non-continuous scheduled period 20D, different repetitions may or may not be separated by a transmission gap 30. This is because the transmission gaps 30 may be defined or configured to occur irrespective of when the repetitions are to occur. Moreover, each of the repetitions may be scheduled for transmission one after another (e.g., based on the same scheduling decision) in a proactive manner irrespective of whether previous repetitions are received successfully. The repetitions may therefore be scheduled during the scheduled period 20D irrespective of any positive or negative acknowledgement (ACK/NACK) for those repetitions or the transmission 16D as a whole.

Despite explanation in the context of NB-loT, eMTC, and 5G in some embodiments, it will be appreciated that the techniques may be applied to other wireless networks. Thus, references herein to signals using terminology from the 3GPP standards should be understood to apply more generally to signals having similar characteristics and/or purposes, in other networks.

A radio node herein is any type of node capable of communicating over radio signals. A radio network node 12 herein is any type of network node (e.g., a base station) capable of communicating with another node over radio signals. A user equipment 14 is any type device capable of communicating with a radio network node 12 or another user equipment 14 over radio signals. A user equipment 14 may therefore refer to a machine-to-machine (M2M) device, a machine-type communications (MTC) device, a NB-loT device, etc. A user equipment 14 may also be referred to as a radio device, a radio communication device, a wireless terminal, or simply a terminal - unless the context indicates otherwise, the use of any of these terms is intended to include device-to-device UEs or devices, machine-type devices or devices capable of machine-to-machine communication, sensors equipped with a wireless device, wireless- enabled table computers, mobile terminals, smart phones, laptop-embedded equipped (LEE), laptop-mounted equipment (LME), USB dongles, wireless customer-premises equipment (CPE), etc. It should be understood that these devices may be UEs, but are generally configured to transmit and/or receive data without direct human interaction.

In an IOT scenario, a user equipment 14 as described herein may be, or may be comprised in, a machine or device that performs monitoring or measurements, and transmits the results of such monitoring measurements to another device or a network. Particular examples of such machines are power meters, industrial machinery, or home or personal appliances, e.g. refrigerators, televisions, personal wearables such as watches etc. In other scenarios, a user equipment 14 as described herein may be comprised in a vehicle and may perform monitoring and/or reporting of the vehicle's operational status or other functions associated with the vehicle.

Note that a radio network node 12 (e.g., a base station) as described above may perform the processing herein by implementing any functional means or units. In one

embodiment, for example, the radio network node comprises respective circuits configured to perform the steps shown in any of Figures 2-9. The circuits in this regard may comprise circuits dedicated to performing certain functional processing and/or one or more microprocessors in conjunction with memory. In embodiments that employ memory, which may comprise one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc., the memory stores program code that, when executed by the one or more microprocessors, carries out the techniques described herein.

Figure 11 A illustrates additional details of a radio network node 12B in accordance with one or more embodiments. As shown, the radio network node 12B includes one or more processing circuits 410 and radio circuitry 420. The radio circuitry 420 may be configured to transmit and/or receive via one or more antennas that are internal and/or external to the radio network node 12B. The one or more processing circuits 410 are configured to perform processing described above, e.g., in Figure 4 and/or 9, such as by executing instructions stored in memory 430. The one or more processing circuits 410 in this regard may implement certain functional means or units.

Figure 1 1 B in this regard illustrates additional details of a radio network node 12B in accordance with one or more other embodiments. Specifically, the radio network node 12B may include a scheduling module or unit 440 for, after a change in channel conditions based on which a first transmission was scheduled for a first user equipment to occur on a radio resource over a scheduled period, scheduling a second transmission for a second user equipment to occur on the radio resource over at least a portion of the scheduled period. The radio network node 12B may further include a transmitting (TX) or receiving (RX) module or unit 450 for transmitting or receiving the second transmission as scheduled. One or more of these modules or units may be implemented by the one or more processing circuits 410 in Figure 11 A.

Similarly, note that a radio node (e.g., a base station or a user equipment) as described above may perform the processing herein by implementing any functional means or units. In one embodiment, for example, the radio node comprises respective circuits configured to perform the steps shown in any of Figures 6-9. The circuits in this regard may comprise circuits dedicated to performing certain functional processing and/or one or more microprocessors in conjunction with memory. In embodiments that employ memory, which may comprise one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc., the memory stores program code that, when executed by the one or more microprocessors, carries out the techniques described herein.

Figure 12A illustrates additional details of a radio node 500 in accordance with one or more embodiments. As shown, the radio node 500 includes one or more processing circuits 510 and radio circuitry 520. The radio circuitry may be configured to transmit and/or receive via one or more antennas that are internal and/or external to the radio node 500. The one or more processing circuits 510 are configured to perform processing described above, e.g., in Figure 9, such as by executing instructions stored in memory 530. The one or more processing circuits 510 in this regard may implement certain functional means or units.

Figure 12B in this regard illustrates additional details of a radio node 500 in accordance with one or more other embodiments. Specifically, the radio node 500 may include a detecting module or unit 540 for detecting a change in channel conditions based on which a transmission was scheduled for a user equipment to occur on over a scheduled period. The radio node 500 may further include a stopping module or unit 550 for, after detecting the change, stopping decoding of or transmitting of the transmission before the end of the scheduled period, e.g., even though the transmission remains scheduled over the scheduled period. One or more of these modules or units may be implemented by the one or more processing circuits 510 in Figure 12A.

Additional details of a radio network node 12 are shown in relation to Figure 13. As shown in Figure 13, the example radio network node 12 includes an antenna 460, radio circuitry (e.g. radio front-end circuitry) 470, processing circuitry 780, and the radio network node 12 may also include a memory 490. The memory 490 may be separate from the processing circuitry 480 or an integral part of processing circuitry 480. Antenna 460 may include one or more antennas or antenna arrays, and is configured to send and/or receive wireless signals, and is connected to radio circuitry (e.g. radio front-end circuitry) 470. In certain alternative embodiments, radio network node 12 may not include antenna 460, and antenna 460 may instead be separate from radio network node 12 and be connectable to radio network node 12 through an interface or port. The radio circuitry (e.g. radio front-end circuitry) 470 may comprise various filters and amplifiers, is connected to antenna 460 and processing circuitry 480, and is configured to condition signals communicated between antenna 460 and processing circuitry 480. In certain alternative embodiments, radio network node 12 may not include radio circuitry (e.g. radio front- end circuitry) 470, and processing circuitry 480 may instead be connected to antenna 460 without front-end circuitry 470.

Processing circuitry 480 may include one or more of radio frequency (RF) transceiver circuitry 482, baseband processing circuitry 484, and application processing circuitry 486. In some embodiments, the RF transceiver circuitry 482, baseband processing circuitry 484, and application processing circuitry 486 may be on separate chipsets. In alternative embodiments, part or all of the baseband processing circuitry 484 and application processing circuitry 486 may be combined into one chipset, and the RF transceiver circuitry 482 may be on a separate chipset. In still alternative embodiments, part or all of the RF transceiver circuitry 482 and baseband processing circuitry 484 may be on the same chipset, and the application processing circuitry 486 may be on a separate chipset. In yet other alternative embodiments, part or all of the RF transceiver circuitry 482, baseband processing circuitry 484, and application processing circuitry 486 may be combined in the same chipset. Processing circuitry 480 may include, for example, one or more central processing units (CPUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), and/or one or more field programmable gate arrays (FPGAs).

The radio network node 12 may include a power source 495. The power source 495 may be a battery or other power supply circuitry, as well as power management circuitry. The power supply circuitry may receive power from an external source. A battery, other power supply circuitry, and/or power management circuitry are connected to radio circuitry (e.g. radio front- end circuitry) 470, processing circuitry 480, and/or memory 490. The power source 495, battery, power supply circuitry, and/or power management circuitry are configured to supply radio network node 12, including processing circuitry 480, with power for performing the functionality described herein.

Additional details of a user equipment 14 are shown in relation to Figure 14. As shown in Figure 14, the example user equipment 14 includes an antenna 560, radio circuitry (e.g. radio front-end circuitry) 570, processing circuitry 580, and the user equipment 14 may also include a memory 590. The memory 590 may be separate from the processing circuitry 580 or an integral part of processing circuitry 580. Antenna 560 may include one or more antennas or antenna arrays, and is configured to send and/or receive wireless signals, and is connected to radio circuitry (e.g. radio front-end circuitry) 570. In certain alternative embodiments, user equipment 14 may not include antenna 560, and antenna 560 may instead be separate from user equipment 14 and be connectable to user equipment 14 through an interface or port. The radio circuitry (e.g. radio front-end circuitry) 570 may comprise various filters and amplifiers, is connected to antenna 560 and processing circuitry 580, and is configured to condition signals communicated between antenna 560 and processing circuitry 580. In certain alternative embodiments, user equipment 14 may not include radio circuitry (e.g. radio front-end circuitry) 570, and processing circuitry 580 may instead be connected to antenna 560 without front-end circuitry 570.

Processing circuitry 580 may include one or more of radio frequency (RF) transceiver circuitry 582, baseband processing circuitry 584, and application processing circuitry 586. In some embodiments, the RF transceiver circuitry 582, baseband processing circuitry 584, and application processing circuitry 586 may be on separate chipsets. In alternative embodiments, part or all of the baseband processing circuitry 584 and application processing circuitry 586 may be combined into one chipset, and the RF transceiver circuitry 582 may be on a separate chipset. In still alternative embodiments, part or all of the RF transceiver circuitry 582 and baseband processing circuitry 584 may be on the same chipset, and the application processing circuitry 586 may be on a separate chipset. In yet other alternative embodiments, part or all of the RF transceiver circuitry 582, baseband processing circuitry 584, and application processing circuitry 586 may be combined in the same chipset. Processing circuitry 580 may include, for example, one or more central processing units (CPUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), and/or one or more field programmable gate arrays (FPGAs).

The user equipment 14 may include a power source 595. The power source 595 may be a battery or other power supply circuitry, as well as power management circuitry. The power supply circuitry may receive power from an external source. A battery, other power supply circuitry, and/or power management circuitry are connected to radio circuitry (e.g. radio front- end circuitry) 570, processing circuitry 580, and/or memory 590. The power source 595, battery, power supply circuitry, and/or power management circuitry are configured to supply user equipment 14, including processing circuitry 580, with power for performing the

functionality described herein.

Those skilled in the art will also appreciate that embodiments herein further include corresponding computer programs.

A computer program comprises instructions which, when executed on at least one processor of a node, cause the node to carry out any of the respective processing described above. A computer program in this regard may comprise one or more code modules corresponding to the means or units described above.

Embodiments further include a carrier containing such a computer program. This carrier may comprise one of an electronic signal, optical signal, radio signal, or computer readable storage medium. The present invention may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

Claims

CLAIMS What is claimed is:

1. A method performed by a radio network node (12B) configured for use in a wireless communication system (10), the method comprising:

after a change in channel conditions based on which a first transmission (16A) was scheduled for a first user equipment to occur on a radio resource (18) over a scheduled period (20), scheduling (102) a second transmission (16B) for a second user equipment to occur on the radio resource (18) over at least a portion of the scheduled period (20); and

transmitting or receiving (104) the second transmission (16B) as scheduled.

2. The method of claim 1 , wherein the change in the channel conditions is indicative that decoding of the first transmission (16A) will fail, or is indicative that early decoding of the first transmission (16A) will succeed before the end of the scheduled period (20).

3. The method of any of claims 1-2, wherein the scheduling of the second transmission (16B) is performed after the channel conditions change by a certain extent.

4. The method of any of claims 1-3, further comprising determining whether or not the channel conditions based on which the first transmission (16A) was scheduled have changed, and wherein the scheduling of the second transmission (16B) is performed after determining that the channel conditions based on which the first transmission (16A) was scheduled have changed.

5. The method of claim 4, wherein the determining is performed at each of one or more predefined times within the scheduled period (20).

6. The method of any of claims 1-5, wherein the first and second transmissions (16A, 16B) are downlink transmissions to the first and second user equipments, and wherein the transmitting or receiving comprises transmitting the second transmission (16B) over at least a portion of the scheduled period (20) during which the first transmission (16A) is not transmitted as scheduled.

7. The method of any of claims 1-6, wherein the first and second transmissions (16A, 16B) are downlink transmissions from the radio network node (12B), and wherein the transmitting or receiving comprises, before the end of the scheduled period (20), switching from transmitting the first transmission (16A) to transmitting the second transmission (16B), such that the radio network node (12B) stops transmitting the first transmission (16A) earlier than scheduled without notifying the first user equipment.

8. The method of any of claims 1-5, wherein the first and second transmissions (16A, 16B) are uplink transmissions, and wherein the transmitting or receiving comprises receiving the second transmission (16B) over at least a portion of the scheduled period (20) during which the first transmission (16A) is also being transmitted as scheduled.

9. The method of any of claims 1-5 and 8, wherein the first and second transmissions (16A, 16B) are uplink transmissions to the radio network node (12B), and wherein the transmitting or receiving comprises, before the end of the scheduled period (20), switching from decoding the first transmission (16A) to decoding the second transmission (16B), such that the radio network node (12B) stops decoding the first transmission (16A) earlier than scheduled even though the first transmission (16A) is still transmitted over the scheduled period (20) as scheduled.

10. The method of any of claims 1-9, further comprising, for each of multiple candidate user equipments, evaluating channel conditions for a transmission to be scheduled for the candidate user equipment on the radio resource (18), assuming the first transmission (16A) is interference to that transmission, and selecting the second user equipment from the multiple candidate user equipments based on the evaluating.

1 1. The method of any of claims 1-10, further comprising selecting the second user equipment to be a user equipment associated with a predicted signal to interference plus noise ratio, SINR, that is higher by at least a defined margin than an SIN R associated with the first user equipment, wherein the predicted SINR includes a signal power associated with the first user equipment as interference.

12. The method of any of claims 1-11 , wherein the wireless communication system (10) is a narrowband internet of things (NB-loT) system.

13. A radio network node (12B) configured for use in a wireless communication system (10), the radio network node (12B) configured to:

after a change in channel conditions based on which a first transmission (16A) was

scheduled for a first user equipment to occur on a radio resource (18) over a scheduled period (20), schedule a second transmission (16B) for a second user equipment to occur on the radio resource (18) over at least a portion of the scheduled period (20); and

transmit or receive the second transmission (16B) as scheduled.

14. The radio network node of claim 13, configured to perform the method of any of claims 2-12.

15. A radio network node (12B) configured for use in a wireless communication system, the radio network node (12B) comprising radio circuitry (420) and processing circuitry (410) wherein the radio network node (12B) is configured to:

after a change in channel conditions based on which a first transmission (16A) was scheduled for a first user equipment to occur on a radio resource (18) over a scheduled period (20), schedule a second transmission (16B) for a second user equipment to occur on the radio resource (18) over at least a portion of the scheduled period (20); and

transmit or receive the second transmission (16B) as scheduled.

16. The radio network node of claim 15, comprising radio circuitry (420) and processing circuitry (410) wherein the radio network node (12B) is configured to perform the method of any of claims 2-12.

17. A radio network node (12B) configured for use in a wireless communication system, the method comprising:

a scheduling module (440) for, after a change in channel conditions based on which a first transmission (16A) was scheduled for a first user equipment to occur on a radio resource (18) over a scheduled period (20), scheduling a second transmission (16B) for a second user equipment to occur on the radio resource (18) over at least a portion of the scheduled period (20); and

a transmitting or receiving module (450) for transmitting or receiving the second

transmission (16B) as scheduled.

18. The radio network node of claim 17, comprising one or more modules for performing the method of any of claims 2-12.

19. A computer program comprising instructions which, when executed by at least one processor of a radio network node (12B), causes the radio network node (12B) to carry out the method of any of claims 1-12.

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

21. A method performed by a radio node (12C, 14C) configured for use in a wireless communication system (10), the method comprising:

detecting (302) a change in channel conditions based on which a transmission (16C) was scheduled for a user equipment (14C) to occur over a scheduled period (20C); and

after detecting the change, stopping (304) decoding of or transmitting of the transmission (16C) before the end of the scheduled period (20C), even though the transmission (16C) remains scheduled over the scheduled period (20C).

22. The method of claim 21 , wherein the detected change is indicative that decoding of the transmission (16C) will fail, or is indicative that early decoding of the transmission (16C) will succeed before the end of the scheduled period (20C).

23. The method of any of claims 21-22, wherein the detecting comprises detecting that the channel conditions have changed by a certain extent.

24. The method of any of claims 21-23, further comprising, at each of one or more predefined times within the scheduled period (20C), detecting whether a change has occurred in the channel conditions based on which the transmission (16C) was scheduled.

25. The method of any of claims 21-24, wherein the stopping comprises stopping decoding of the transmission (16C) before the end of the scheduled period (20C), even though the transmission (16C) remains scheduled over the scheduled period (20C).

26. The method of any of claims 21-24, wherein the stopping comprises stopping transmitting of the transmission (16C) before the end of the scheduled period (20C), even though the transmission (16C) remains scheduled over the scheduled period (20C).

27. The method of any of claims 21-26, wherein the wireless communication system is a narrowband internet of things (NB-loT) system.

28. A radio node (12C, 14C) configured for use in a wireless communication system (10), the radio node (12C, 14C) configured to:

detecting a change in channel conditions based on which a transmission (16C) was scheduled for a user equipment (14C) to occur on over a scheduled period

(20C); and after detecting the change, stop decoding of or transmitting of the transmission (16C) before the end of the scheduled period (20C), even though the transmission (16C) remains scheduled over the scheduled period (20C).

29. The radio node of claim 28, configured to perform the method of any of claims 22-27.

30. A radio node (12C, 14C) configured for use in a wireless communication system (10), the radio node (12C, 14C) comprising radio circuitry (520) and processing circuitry (510) wherein the radio node (12C, 14C) is configured to:

detect a change in channel conditions based on which a transmission (16C) was

scheduled for a user equipment (14C) to occur on over a scheduled period (20C); and

after detecting the change, stop decoding of or transmitting of the transmission (16C) before the end of the scheduled period (20C), even though the transmission (16C) remains scheduled over the scheduled period (20C).

31. The radio node of claim 30, comprising radio circuitry (520) and processing circuitry (510) wherein the radio node (12C, 14C) is configured to perform the method of any of claims 22-27.

32. A radio node (12C, 14C) configured for use in a wireless communication system, the radio node (12C, 14C) comprising:

a detecting module (540) for detecting a change in channel conditions based on which a transmission (16C) was scheduled for a user equipment to occur on over a scheduled period (20C); and

a stopping module (550) for, after detecting the change, stopping decoding of or

transmitting of the transmission (16C) before the end of the scheduled period (20C), even though the transmission (16C) remains scheduled over the scheduled period (20C).

33. The radio node of claim 32, comprising one or more modules for performing the method of any of claims 22-27.

34. A computer program comprising instructions which, when executed by at least one processor of a radio node (12C, 14C), causes the radio node (12C, 14C) to carry out the method of any of claims 21-27.

35. A carrier containing the computer program of claim 34, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.