SPS with skipping transmissions and adaptive HARQ

In one embodiment, a method in a wireless device for adaptive HARQ retransmissions comprises receiving, from a network node, a request to initiate an adaptive hybrid automatic repeat request (HARQ) retransmission. The method comprises identifying a HARQ process associated with the HARQ retransmission request and determining whether a HARQ buffer of the HARQ process is empty. In response to determining that the HARQ buffer is empty, the method comprises not delivering the HARQ information to the HARQ process and not triggering an adaptive HARQ retransmission.

TECHNICAL FIELD

The present disclosure relates generally to wireless communications and, more specifically, to SPS with skipping transmissions and adaptive HARQ.

BACKGROUND

In LTE-Rel-13 and LTE-Rel-14, latency reduction techniques are discussed and standardized in 3GPP. One latency reduction technique allows the eNB to configure a UE with semi-persistent scheduling (SPS) and, when no uplink (UL) data is available, the possibility of allowing the UE to skip uplink transmissions.

In SPS, the UE is configured with an uplink grant which is valid during the RRC configured SPS-occasions, e.g. every 10 ms or every 1 ms. When UL data is available, the UE can use the configured UL grant for transmission. According to pre-Rel-14 behavior, when no data is available for transmission, the UE sends a padding transmission on the configured UL grant. In Rel-14 it is standardized to allow skipping of these padding transmissions.

However, the UE's ability to skip transmissions introduced an uncertainty in the eNB. The eNB may question whether the UE intentionally skipped a transmission or whether an error occurred with the UE transmission. This uncertainty may cause the eNB to send a retransmission request to the UE. Retransmissions in SPS can be handled by non-adaptive and adaptive HARQ retransmissions. Adaptive retransmissions have the advantage that the used redundancy version can be adjusted leading to a more reliable retransmission. Generally, the eNB sends another PDCCH UL grant to the UE, triggering an adaptive HARQ retransmission by the UE.

A number of technical issues arise when a UE receives an adaptive HARQ retransmission grant triggered from the eNB after previously skipping a UL transmission.

SUMMARY

To address the foregoing problems, disclosed is a method in a wireless device for adaptive HARQ retransmissions. The method comprises receiving, from a network node, a request to initiate an adaptive hybrid automatic repeat request (HARQ) retransmission. The HARQ retransmission request may comprise HARQ information. The method may then identify a HARQ process associated with the HARQ retransmission request, determine whether a HARQ buffer of the HARQ process is empty, and in response to determining that the HARQ buffer is empty, not delivering the HARQ information to the HARQ process not triggering an adaptive HARQ retransmission.

In certain embodiments, the method may further include determining that a medium access control (MAC) entity of the wireless device is configured to skip an uplink transmission when no uplink data is available.

In certain embodiments, the method may further comprise determining that an uplink grant received on a physical downlink control channel (PDCCH) was addressed to the semi-persistent scheduling (SPS) cell radio network temporary identifier (C-RNTI).

In certain embodiments, prior to receiving the HARQ retransmission request from the network node, the method may further comprise determining that no uplink data is available for transmission to the network node and skipping a scheduled uplink transmission to the network node.

In certain embodiments, the request to initiate a HARQ retransmission received from the network node comprises a new data indicator (NDI) that has not been toggled.

Also disclosed is a wireless device. The wireless device comprises an interface and processing circuitry communicatively coupled to the interface. The interface may be configured to receive, from a network node, a request to initiate a HARQ retransmission. The HARQ retransmission request may comprise HARQ information. The processing circuitry may be configured to identify a HARQ process associated with the HARQ retransmission request, determine whether a HARQ buffer of the HARQ process is empty, and in response to determining that the HARQ buffer is empty, not triggering an adaptive HARQ retransmission.

In certain embodiments, the processing circuitry of the wireless device is further configured to determine that a MAC entity of the wireless device is configured to skip an uplink transmission when no uplink data is available.

In certain embodiments, the processing circuitry of the wireless device is further configured to determine that an uplink grant received on a PDCCH was addressed to the SPS C-RNTI.

In certain embodiments, prior to the interface receiving the HARQ retransmission request from the network node, the processing circuitry of the wireless device is further configured to determine that no uplink data is available for transmission to the network nodes, and skip a scheduled uplink transmission to the network node.

Also disclosed is a method performed by a network node for adaptive HARQ retransmissions in a communication network. The method comprising determining that an uplink transmission from a wireless device was not received, transmitting an adaptive HARQ retransmission request to the wireless device, determining that an adaptive HARQ retransmission was not received from the wireless device, determining whether to transmit another adaptive HARQ retransmission request to the wireless device, and in response to determining that another adaptive HARQ retransmission request should not be sent to the wireless device, stopping additional adaptive HARQ retransmission requests to the wireless device.

In certain embodiments, in response to determining that another adaptive HARQ retransmission request should be sent to the wireless device, the method may further comprise transmitting an adaptive HARQ retransmission request to the wireless device.

In certain embodiments, determining whether to transmit another adaptive HARQ retransmission request to the wireless device comprises counting a number of adaptive HARQ retransmission requests that have previously been sent to the wireless device, and determining that another adaptive HARQ retransmission request should not be sent when the number of adaptive HARQ retransmission requests reaches a preconfigured number. In certain embodiments, the preconfigured number is less than five.

In certain embodiments, in response to determining that another adaptive HARQ retransmission request should not be sent to the wireless device, the method further comprises determining that the wireless device skipped transmitting the uplink transmission.

Also disclosed is a network node. The network node comprises processing circuitry and an interface communicatively coupled to the processing circuitry. The processing circuitry may be configured to determine that an uplink transmission from a wireless device was not received. The interface may be configured to transmit an adaptive HARQ retransmission request to the wireless device. The processing circuitry is further configured to determine that an adaptive HARQ retransmission was not received from the wireless device, determine whether to transmit another adaptive HARQ retransmission request to the wireless device, in response to determining that another adaptive HARQ retransmission request should not be sent to the wireless device, stopping scheduling of another adaptive HARQ retransmission requests to the wireless device.

In certain embodiments, in response to determining that another adaptive HARQ retransmission request should be sent to the wireless device, the interface is further configured to transmit an adaptive HARQ retransmission request to the wireless device.

In certain embodiments, to determine whether to transmit another adaptive HARQ retransmission request to the wireless device, the processing circuitry is configured to count a number of adaptive HARQ retransmission requests that have previously been sent to the wireless device, and determine that another adaptive HARQ retransmission request should not be sent when the number of adaptive HARQ retransmission requests reaches a preconfigured number. In certain embodiments, the preconfigured number is less than five.

Certain embodiments of the present disclosure may provide one or more technical advantages. For example, certain embodiments may advantageously allow for well-defined UE behavior, which avoids potential unexpected errors in communication between an eNB and the UE. Certain embodiments of the present disclosure represent HARQ retransmissions. As another example, certain embodiments may advantageously reduce PDCCH resources. Other advantages may be readily apparent to one having skill in the art. Certain embodiments may have none, some, or all of the recited advantages.

DETAILED DESCRIPTION

As described above, it is unclear how a wireless device, such as a UE, should react when adaptive HARQ retransmissions are triggered by an evolved Node B (eNB) after the UE has skipped an uplink transmission. For example, if a UE does not have information to transmit, the UE may skip a UL transmission. The eNB may not identify that the UE skipped the UL transmission and may instead assume that the UL transmission failed. In response, the eNB may schedule an adaptive hybrid automatic repeat request (HARQ) retransmission. Upon receiving the HARQ retransmission grant, the UE may initiate an adaptive HARQ retransmission of the current HARQ buffer. However, since the UE did not previously transmit any data, the current buffer is empty.

An issue therefore exists regarding how the UE should react when receiving an adaptive HARQ retransmission grant when the HARQ buffer is empty. Because there is no current solution to this issue, the behavior of the UE cannot be anticipated, which may lead to additional unexpected error in the eNB and/or the UE. To overcome these issues, embodiments of the present disclosure provide solutions to handle adaptive HARQ retransmissions for SPS configured wireless devices that have skipped UL transmissions.

According to one embodiment, when the HARQ buffer of the process is empty, upon receiving the adaptive HARQ retransmission grant from the network node, the wireless device will determine that no adaptive HARQ retransmission should be performed and will ignore the adaptive HARQ retransmission grant. Thus, no adaptive HARQ retransmission is triggered. The eNB which triggered the retransmission grant will again not receive any response from the UE. The eNB may schedule another adaptive HARQ retransmission, which again, will not be sent by the UE. The eNB may stop scheduling adaptive HARQ retransmissions after a configurable number of retransmission attempts is reached.

Providing a well-defined UE response to adaptive HARQ retransmission grants when the UE has skipped a UL transmission provides a number of technical advantages not realized by current systems. Certain embodiments may advantageously allow for well-defined UE behavior, which avoids potential unexpected errors in communication between an eNB and the UE. As another example, certain embodiments may advantageously reduce PDCCH resources.FIGS. 1-10provide additional details of SPS with skipping transmissions and adaptive HARQ that may provide these and other advantages.

FIG. 1is a schematic diagram of a wireless communication network100, in accordance with certain embodiments. In the illustrated embodiment,FIG. 1includes network120, network nodes100a-b(network node100amay be referenced generally as “network node100”), and wireless device110. Network node100may be interchangeably referred to as eNodeB (eNB)100. Wireless device110may be interchangeably referred to as user equipment (UE)110. In different embodiments, the wireless network may comprise any number of wired or wireless networks, network nodes, base stations (BS), controllers, wireless devices, relay stations, and/or any other components that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections.

Network120may comprise one or more IP networks, public switched telephone networks (PSTNs), packet data networks, optical networks, wide area networks (WANs), local area networks (LANs), wireless local area networks (WLANs), wired networks, wireless networks, metropolitan area networks, and other networks to enable communication between devices.

Network node100may refer to any kind of network node100, which may comprise a Node B, base station (BS), radio base station, multi-standard radio (MSR) radio node such as MSR BS, eNode B, network controller, radio network controller (RNC), multi-cell/multicast coordination entity (MCE), base station controller (BSC), relay node, base transceiver station (BTS), access point (AP), radio access point, transmission points, transmission nodes, remote radio unit (RRU), remote radio head (RRH), nodes in distributed antenna system (DAS), core network node (e.g., MSC, MME, SON node, coordinating node, etc.), O&M, OSS, positioning node (e.g., E-SMLC), MDT, an external node (e.g., third-party node, a node external to the current network), or any suitable network node.

Network node100comprises interface101, processor102, storage103, and antenna104. These components are depicted as single boxes located within a single larger box. In practice however, a network node100may comprise multiple different physical components that make up a single illustrated component (e.g., interface101may comprise terminals for coupling wires for a wired connection and a radio transceiver for a wireless connection). As another example, network node100may be a virtual network node in which multiple different physically separate components interact to provide the functionality of network node100(e.g., processor102may comprise three separate processors located in three separate enclosures, where each processor is responsible for a different function for a particular instance of network node100). Similarly, network node100may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, a BTS component and a BSC component, etc.), which may each have their own respective processor, storage, and interface components. In certain scenarios in which network node100comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple

NodeB's. In such a scenario, each unique NodeB and BSC pair, may be a separate network node. In some embodiments, network node100may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate storage103for the different RATs) and some components may be reused (e.g., the same antenna104may be shared by the RATs).

Processor102may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, processing circuitry, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in conjunction with other network node100components, such as storage103, network node100functionality. For example, processor102may execute instructions stored in storage103. Such functionality may include providing various wireless features discussed herein to a wireless devices, such as wireless device110, including any of the features or benefits disclosed herein.

Storage103may comprise any form of volatile or non-volatile computer readable memory including, without limitation, persistent storage, solid state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), removable media, or any other suitable local or remote memory component. Storage103may store any suitable instructions, data or information, including software and encoded logic, utilized by network node100. Storage103may be used to store any calculations made by processor102and/or any data received via interface101.

Network node100also comprises interface101which may be used in the wired or wireless communication of signalling and/or data between network node100, network120, and/or wireless device110. For example, interface101may perform any formatting, coding, or translating that may be needed to allow network node100to send and receive data from network120over a wired connection. Interface101may also include a radio transmitter and/or receiver that may be coupled to or a part of antenna104. The radio may receive digital data that is to be sent out to other network nodes or wireless devices110via a wireless connection. The radio may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters. The radio signal may then be transmitted via antenna104to the appropriate recipient (e.g., wireless device110).

Antenna104may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In some embodiments, antenna104may comprise one or more omni-directional, sector or panel antennas operable to transmit/receive radio signals between, for example, 2 GHz and 66 GHz. An omni-directional antenna may be used to transmit/receive radio signals in any direction, a sector antenna may be used to transmit/receive radio signals from devices within a particular area, and a panel antenna may be a line of sight antenna used to transmit/receive radio signals in a relatively straight line.

Wireless device110may be any type of wireless endpoint, mobile station, mobile phone, wireless local loop phone, smartphone, user equipment (UE), desktop computer, PDA, cell phone, tablet, laptop, VoIP phone or handset, which is able to wirelessly send and receive data and/or signals to and from a network node, such as network node100and/or other wireless devices110. For example, wireless device110may transmit wireless signals to one or more of network nodes110a-b, and/or receive wireless signals from one or more of network nodes110a-b. The wireless signals may contain voice traffic, data traffic, control signals, and/or any other suitable information. In some embodiments, an area of wireless signal coverage associated with a network node110may be referred to as a cell. In some embodiments, wireless device110may have device-to-device (D2D) capability. Thus, wireless device110may be able to receive signals from and/or transmit signals directly to another wireless device.

Wireless device110comprises interface111, processor112, storage113, and antenna114. Like network node100, the components of wireless device110are depicted as single boxes located within a single larger box, however in practice a wireless device may comprises multiple different physical components that make up a single illustrated component (e.g., storage113may comprise multiple discrete microchips, each microchip representing a portion of the total storage capacity).

The wireless network may utilize wireless device110and network node100to implement the HARQ operations. HARQ operations provide error control and data recovery in the wireless network. The HARQ operations may be performed by HARQ entities. There is typically one HARQ entity at the MAC entity of a wireless device110for each service cell of the wireless network with a configured uplink. Thus, if wireless device110is communicating with network node100aand network node100b, then wireless device110may have two different HARQ entities in the MAC layer of wireless device110. Each HARQ entity may maintain a number of parallel HARQ processes that allow for transmission to take place continuously while waiting for the HARQ feedback on the successful or unsuccessful reception of previous transmissions. For example, in some embodiments, when the physical layer is configured for uplink spatial multiplexing, there may be two HARQ processes associated with a given transmission time interval (TTI). For a given TTI, if an uplink grant is indicated for the TTI, the HARQ entity may identify the HARQ process(es) for which a transmission should take place.

Accordingly, a HARQ entity of wireless device110may identify the HARQ process associated with the TTI for which an uplink grant has been provided. In some embodiments, for a given TTI, if wireless device110determines that the MAC entity is configured to skip UL transmissions (e.g., the MAC entity of wireless device110is configured with skipUplinkTxSPS); the uplink grant received on PDCCH was addressed to the SPS cell radio network temporary identifier (C-RNTI); and the HARQ buffer of the identified HARQ process is empty, then wireless device110may ignore the uplink grant and not perform an adaptive HARQ retransmission.

Interface111may be used in the wireless communication of signalling and/or data between wireless device110and network node100. For example, interface111may perform any formatting, coding, or translating that may be needed to allow wireless device110to send and receive data from network node100over a wireless connection. Interface111may also include a radio transmitter and/or receiver that may be coupled to or a part of antenna114. The radio may receive digital data that is to be sent out to network node100via a wireless connection. The radio may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters. The radio signal may then be transmitted via antenna114to network node100.

Processor112may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, processing circuitry, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in combination with other wireless device110components, such as storage113, wireless device110functionality. Such functionality may include providing various wireless features discussed herein, including any of the features or benefits disclosed herein.

Storage113may be any form of volatile or non-volatile memory including, without limitation, persistent storage, solid state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), removable media, or any other suitable local or remote memory component. Storage113may store any suitable data, instructions, or information, including software and encoded logic, utilized by wireless device110. Storage113may be used to store any calculations made by processor112and/or any data received via interface111.

Antenna114may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In some embodiments, antenna114may comprise one or more omni-directional, sector or panel antennas operable to transmit/receive radio signals between 2 GHz and 66 GHz. For simplicity, antenna114may be considered a part of interface111to the extent that a wireless signal is being used.

In certain embodiments, network nodes100may interface with a radio network controller. The radio network controller may control network nodes100and may provide certain radio resource management functions, mobility management functions, and/or other suitable functions. In certain embodiments, the functions of the radio network controller may be performed by network node100. The radio network controller may interface with a core network node. In certain embodiments, the radio network controller may interface with the core network node via an interconnecting network. The interconnecting network may refer to any interconnecting system capable of transmitting audio, video, signals, data, messages, or any combination of the preceding. The interconnecting network may include all or a portion of a PSTN, a public or private data network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a local, regional, or global communication or computer network such as the Internet, a wireline or wireless network, an enterprise intranet, or any other suitable communication link, including combinations thereof.FIG. 8describes additional functionality of a radio network controller.

In some embodiments, the core network node may manage the establishment of communication sessions and various other functionalities for wireless device110. Wireless device110may exchange certain signals with the core network node using the non-access stratum (NAS) layer. In non-access stratum signaling, signals between wireless devices110and the core network node may be transparently passed through the radio access network. In certain embodiments, network nodes100may interface with one or more network nodes over an internode interface. For example, network nodes100aand100bmay interface over an X2 interface.

AlthoughFIG. 1illustrates a particular arrangement of a wireless network, the present disclosure contemplates that the various embodiments described herein may be applied to a variety of networks having any suitable configuration. For example, the wireless network may include any suitable number of wireless devices110and network nodes100, as well as any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device (such as a landline telephone). Furthermore, although certain embodiments may be described as implemented in a long-term evolution (LTE) network, the embodiments may be implemented in any appropriate type of telecommunication system supporting any suitable communication standards and using any suitable components, and are applicable to any RAT or multi-RAT systems in which the wireless device receives and/or transmits signals (e.g., data). For example, the various embodiments described herein may be applicable to NR, LTE, LTE-Advanced, UMTS, HSPA, GSM, cdma2000, WiMax, WiFi, another suitable radio access technology, or any suitable

As described above, the present disclosure contemplates various embodiments that provide solutions to handle adaptive HARQ retransmissions for SPS configured wireless devices110that have skipped UL transmissions to network node100. For example, in one embodiment, a wireless device110may determine that no data is available for transmission and decide to skip a UL transmission. Network node100may determine that no UL transmission was received from wireless device110. Network node100may schedule an adaptive HARQ operation by sending another UL grant over the physical downlink control channel (PDCCH) to wireless device110, indicated to the SPS resources.

Upon receiving the adaptive HARQ retransmission grant (also referred to as a request), wireless device110may respond in several ways. In one embodiment, wireless device110may receive the adaptive HARQ retransmission grant and initiate an adaptive HARQ retransmission of the current HARQ buffer. In some embodiments, wireless device110will have skipped the UL transmission and the current HARQ buffer will be empty. Upon determining that the HARQ buffer of the process is empty, wireless device110may then decide not to deliver the received HARQ information from the adaptive HARQ retransmission grant to the HARQ process. Wireless device110may then decide not to trigger an adaptive HARQ retransmission. In this manner, wireless device110will ignore the uplink grant from network node100when: (1) wireless device110skips an UL transmission (e.g., when the MAC entity of wireless device110is configured with skipUplinkTxSPS); (2) wireless device110receives an uplink grant on the PDCCH addressed to the SPS cell radio network temporary identifier (C-RNTI); and (3) the HARQ buffer of the identified process is empty.

Any appropriate steps, methods, or functions may be performed through a computer program product that may, for example, be executed by the components and equipment illustrated in the figure above. For example, storage103may comprise non-transitory computer readable means on which a computer program can be stored. The computer program may include instructions which cause processor102(and any operatively coupled entities and devices, such as interface101and storage103) to execute methods according to embodiments described herein. The computer program and/or computer program product may thus provide means for performing any steps herein disclosed.

FIGS. 2-5are additional illustrate embodiments of the present disclosure describe how to handle adaptive HARQ retransmissions for SPS configured wireless device110communicating with network nodes100a-b.

FIG. 2illustrates a signal flow diagram200describing a first option for responding to an adaptive HARQ retransmission request, in accordance with certain embodiments. At a high level, signal flow diagram200describes an embodiment wherein wireless device110will ignore the adaptive HARQ retransmission grant transmitted from network node100when certain conditions are present.

At step201, wireless device110may skip an uplink transmission to network node100. For example, wireless device110may skip an uplink transmission when wireless device110is configured for SPS and has the ability to skip UL transmissions when no UL data is available.

At step202, since wireless device110skipped the UL transmission, network node100fails to receive a transmission from wireless device110. Network node100may not recognize that wireless device110skipped the uplink transmission and, instead, may assume that the UL transmission failed. Network node100may respond by scheduling an adaptive HARQ retransmission. In some embodiments, an adaptive HARQ retransmission may be indicated by addressing the SPS RNTI of wireless device110and by setting the new data indicator (NDI) field to 1 (i.e., indicating that NDI is not toggled). Network node100may then transmit adaptive HARQ retransmission grant S210to wireless device110.

At step203, wireless device110may receive signal S210and determine whether the HARQ buffer of the current process is empty. Here, since wireless device110skipped the UL transmission at step201, the HARQ buffer of the current process will be empty. In some embodiments, wireless device110may ignore the adaptive HARQ retransmission grant (i.e., S210) when it is determined that the MAC entity of wireless device110is configured to skip UL transmissions (i.e., the MAC entity is configured with skipUplinkTxSPS) and/or when the UL grant (i.e., the adaptive HARQ retransmission signal S210) received on PDCCH was addressed to semi-persistent scheduling C-RNTI.

Upon determining that the HARQ buffer is empty, at step204, wireless device110may ignore the adaptive HARQ retransmission request signal S210. For example, wireless device110may not deliver the received HARQ information from the adaptive HARQ retransmission request to the HARQ process and may not trigger an adaptive HARQ retransmission.

At step205, network node100will again not receive any retransmission from wireless device110. In some embodiments, network node100may schedule another adaptive HARQ retransmission request for wireless device110. In some embodiments, network node100may stop scheduling adaptive HARQ retransmissions after determining that wireless device110is ignoring the retransmission request or upon determining that wireless device110skipped the UL transmission. For example, in some embodiments, network node100may stop scheduling adaptive HARQ retransmissions after a configurable number of retransmission attempts have been tried. The configurable number of retransmission attempts may be set to any suitable number (e.g., 0-5 attempts). In some embodiments, the preconfigured number may be set to a limit (e.g., the preconfigured number is less than five). While the above embodiments discuss using a configurable number to determine when to stop scheduling retransmission attempts, any suitable process may be used to determine when network node100should stop scheduling adaptive HARQ retransmissions.

At step205, if network node100determines that another adaptive HARQ retransmission should be sent to wireless device110, network node100may again send adaptive HARQ retransmission grant210to wireless device110. The process of steps203-205may then repeat until network node100determines that another adaptive HARQ retransmission should not be sent and/or until network node100identifies that wireless device110skipped the UL transmission at step201.

FIG. 3illustrates a signal flow diagram300describing a second option for responding to an adaptive HARQ retransmission request, in accordance with certain embodiments. Generally, signal flow diagram300describes an embodiment wherein wireless device110will transmit new data, when available, in response to the adaptive HARQ retransmission grant transmitted from network node100when certain conditions are present. Network node100and wireless device110may perform steps201-203and S210described above in reference toFIG. 2. Therefore, only steps that are new toFIG. 3will be described.

At step301, wireless device110may receive signal S210and initiate an adaptive HARQ retransmission of the HARQ buffer of the current process. At step302wireless device110determines whether new data is available for transmission. If new data is available, the data can be sent directly to network node100. Thus, instead of transmitting padding or skipping the UL retransmission, wireless device110may send the new data. This embodiment allows for resources to not be wasted by unnecessary transmissions (e.g., padding) or missed opportunities to transmit data (e.g., skipping the UL transmission). In some embodiments, if no new data is available, wireless device110may operate as described inFIG. 2and ignore the adaptive HARQ retransmission request.

If wireless device110determines that new data is available for transmission at step302, wireless device110may transmit new data S310to network node100. At step303, network node100receives the new data and may identify that wireless device110transmitted new data. At step304, based on the reception of new data, network node100may determine that wireless device110skipped a UL transmission at step201. If network node100determines that wireless device110skipped the UL transmission for which adaptive HARQ retransmission signal S210was previously sent, network node100may then determine not to schedule another retransmission request.

FIG. 4illustrates a signal flow diagram400describing a third option for responding to an adaptive HARQ retransmission request, in accordance with certain embodiments. Signal flow diagram400describes an embodiment wherein wireless device110will transmit an indication to network node100, which informs network node100that wireless device110skipped the UL transmission. Network node100and wireless device110may perform steps201-203,301, and S210described above in reference toFIGS. 2 and 3. Therefore, only steps that are new toFIG. 4will be described.

After receiving the adaptive HARQ retransmission grant S210from network node100and determining that the HARQ buffer of the current process is empty, wireless device110may transmit indication S410to network node100.

At step401, network node100may receive indication signal S410. Indication signal S410may indicate to network node100that wireless device110skipped the UL transmission at step201and, therefore, network node100should not schedule another adaptive HARQ retransmission. By not scheduling additional adaptive HARQ retransmissions, no further PDCCH resources are wasted. Accordingly at step402, network node100determines that wireless device110skipped the UL transmission and determines that no further adaptive HARQ retransmissions should be scheduled.

Indication signal S410may take any suitable format and include any suitable data. Moreover, the contents of indication signal S410may change based on one or more factors. For example, if wireless device110has new data to transmit, indication signal S410may include the new data. In this embodiment, upon receiving the new data, network node100may react as described in steps303and304fromFIG. 3. If no new data is available, wireless device110may instead transmit padding as part of indication signal S410. In some embodiments, wireless device110may always send padding as part of indication signal S410, independent of whether new data is available.

In certain embodiments, wireless device110may transmit a MAC control element as part of indication signal S410. The MAC control element may indicate to network node100that wireless device110skipped the UL transmission at step201and there is nothing for retransmission.

FIG. 5illustrates a signal flow diagram500describing a fourth option for responding to an adaptive HARQ retransmission request, in accordance with certain embodiments. Signal flow diagram500describes an embodiment wherein the corresponding data that should have been sent, such as padding or regular BSR, is stored in the HARQ buffer of the current process. Thus, if network node100transmits another adaptive HARQ retransmission, the HARQ buffer of the current process will no longer be empty and may transmit the stored information. Network node100and wireless device110may perform steps201-205,301and S210described above in reference toFIGS. 2 and 3. Therefore, only steps that are new toFIG. 5will be described.

After receiving adaptive HARQ retransmission grant S210from network node100and determining that the HARQ buffer of the current process is empty (step203), at step501, wireless device110may store the corresponding data that should have been sent, the MAC PDU for transmission (padding BSR, regular BSR, etc.) in the HARQ buffer of the current HARQ process. In some embodiments, wireless device110may then decide not to transmit a response signal to network node100.

As described above, at step205, network node100, which triggered the original retransmission grant, will again not receive any retransmission from wireless device110. In some embodiments, network node100may schedule another adaptive HARQ retransmission request for wireless device110. If network node100determines that an additional adaptive HARQ retransmission request should be sent to wireless device110(e.g., using signal S210), wireless device110may respond using the stored MAC PDU in the HARQ buffer. In this manner, wireless device110may skip an UL transmission and skip an initial response to an adaptive HARQ retransmission grant. However, should an additional retransmission grant be received by wireless device110, the HARQ buffer of the current process will no longer be empty and wireless device110may transmit the stored information.

Based on the forgoing descriptions ofFIGS. 2-5, the present disclosure contemplates a number of embodiments for how to handle adaptive HARQ retransmissions for SPS configured wireless devices110that have skipped UL transmissions to network nodes100a-b.FIGS. 6 and 7provide additional detail on methods of SPS with skipping transmissions and adaptive HARQ.

FIG. 6is a flow chart of a method600in a wireless device110, in accordance with certain embodiments. In some embodiments, method600may be performed by wireless device110receiving an adaptive HARQ retransmission request. At step602, wireless device110may skip a UL transmission to network node100. However, in some embodiments, step602may be optional and the method may begin with step604. At step604, wireless device110may receive an adaptive HARQ retransmission request from network node100. In some embodiments, the adaptive HARQ retransmission grant may be indicated by addressing the SPS RNTI of wireless devices110and/or by setting the NDI to 1 (i.e., indicating that NDI is not toggled).

Upon receiving the HARQ retransmission grant, wireless device may initiate an adaptive HARQ retransmission of the HARQ buffer of the current process. For example, at step606wireless device110may determine that the HARQ buffer of the current HARQ process is empty since wireless device110skipped the earlier UL transmission at step602. Upon determining that the HARQ buffer is empty, at step608, wireless device110may ignore the adaptive HARQ retransmission grant from network node100. In some embodiments, ignoring the adaptive HARQ retransmission grant may include not delivering the received HARQ information from the adaptive HARQ retransmission grant to the current HARQ process and/or not triggering an adaptive HARQ retransmission.

In some embodiments, before ignoring the adaptive HARQ retransmission grant, wireless device110may also determine that the MAC entity of wireless device110is configured to skip UL transmissions and/or that the UL grant received on PDCCH was addressed to semi-persistent scheduling C-RNTI. After step608, the method may end.

FIG. 7is a flow chart of a method700in a network node100, in accordance with certain embodiments. In some embodiments, method700may be performed by network node100is for adaptive HARQ retransmissions in a communication network. At step702, network node100may determine that a UL transmission from wireless device110was not received. Network node100may not know whether wireless device110intentionally skipped a UL transmission or whether an error occurred with the UL transmission.

At step704, network node100may transmit an adaptive HARQ retransmission request to wireless device100. However, in certain situations wireless device110may not respond to the retransmission request. For example, if wireless device110is performing the method described inFIG. 6, wireless device110may ignore the adaptive HARQ retransmission request when wireless device110skipped the UL transmission.

At step706, network node100may determine that no adaptive HARQ retransmission was received from wireless device110. Network node100may still be unclear whether wireless device110is intentionally non-responsive or whether there is a continuing transmission error. Thus, at step708, network node100determines whether to transmit another adaptive HARQ retransmission request to wireless device110. For example, in some embodiments, network node100may stop scheduling adaptive HARQ retransmissions after a configurable number of retransmission attempts have been tried. The configurable number of retransmission attempts may be set to any suitable number, including but not limited to 0-5 attempts. As another example, network node100may stop scheduling adaptive HARQ retransmissions after determining that wireless device110is ignoring the retransmission request or upon determining that wireless device110skipped the UL transmission. The foregoing examples are merely illustrative. Any suitable process may be used to determine when network node100should stop scheduling adaptive HARQ retransmissions.

If network node100determines at step708to transmit another adaptive HARQ retransmission, the process may return to step704. In some embodiments, network node100may also update an internal counter to keep track of the number of times an adaptive HARQ retransmission request has been sent to wireless device110.

If network node100determines at step708to not transmit another adaptive HARQ retransmission, the process may proceed to step710. At step710, network node100may stop sending adaptive HARQ retransmission requests to the wireless device. In some embodiments, network node100may assume that network node100skipped the UL transmission and that any further retransmission requests would unnecessarily waste PDCCH resources and/or create undesired PDCCH interference.

FIG. 8is a schematic block diagram of an exemplary radio network controller or core network node810, in accordance with certain embodiments. Examples of network nodes can include a mobile switching center (MSC), a serving GPRS support node (SGSN), a mobility management entity (MME), a radio network controller (RNC), a base station controller (SC), and so on. The radio network controller or core network node810includes processor820, memory830, and network interface840. In some embodiments, processor820executes instructions to provide some or all of the functionality described above as being provided by the network node, memory830stores the instructions executed by processor820, and network interface840communicates signals to any suitable node, such as a gateway, switch, router, Internet, Public Switched Telephone Network (PSTN), network nodes100, radio network controllers or core network nodes810, etc.

In some embodiments, network interface840is communicatively coupled to processor820and may refer to any suitable device operable to receive input for the network node, send output from the network node, perform suitable processing of the input or output or both, communicate to other devices, or any combination of the preceding. Network interface840may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.

Other embodiments of the network node may include additional components beyond those shown inFIG. 8that may be responsible for providing certain aspects of the network node's functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the embodiments described above).

FIG. 9is a schematic block diagram of an exemplary wireless device110, in accordance with certain embodiments. Wireless device110may include one or more modules. For example, wireless device110may include a determining module910, a communication module920, and a receiving module930. Optionally, wireless device110may include an input module940, a display module950, and any other suitable modules. Wireless device110may perform the response to receiving an adaptive HARQ retransmission request described above with respect toFIGS. 1-7.

Determining module910may perform the processing functions of wireless device110. In certain embodiments, wireless device110may perform any of the functions described above with respect toFIGS. 1-7. In one example embodiment, determining module910may decide to skip an uplink transmission to network node100. For example, in some embodiments, wireless device110may skip an uplink transmission when wireless device110is be configured for SPS and has the ability to skip UL transmissions when no UL data is available. In response to receiving an adaptive HARQ retransmission request from network node100, determining module910may also initiate an adaptive HARQ retransmission of the HARQ buffer of the current process. For example, determining module910may determine that the HARQ buffer of the current HARQ process is empty since wireless device110skipped the earlier UL transmission. Upon determining that the HARQ buffer is empty, determining module910may ignore the request to initiate an adaptive HARQ retransmission from network node100(e.g., ignore the UL grant).

In some embodiments, ignoring the adaptive HARQ retransmission grant may include not delivering the received HARQ information from the adaptive HARQ retransmission grant to the current HARQ process and/or not triggering an adaptive HARQ retransmission. According to another example embodiment, determining module910may determine that the MAC entity of wireless device110is configured to skip UL transmissions and/or that the UL grant received on PDCCH was addressed to semi-persistent scheduling C-RNTI, before ignoring the adaptive HARQ retransmission grant.

Determining module910may include or be included in one or more processors, such as processor112described above in relation toFIG. 1. Determining module910may include analog and/or digital circuitry configured to perform any of the functions of determining module910and/or processor112described above. The functions of determining module910described above may, in certain embodiments, be performed in one or more distinct modules.

Communication module920may perform the communication functions of wireless device110. In certain embodiments, communication module920may perform any of the communication functions described above with respect toFIGS. 1-7. In some embodiments, communication module920may transmit signals to network node110in response to wireless device110receiving the adaptive HARQ retransmission request. For example, communication module920may transmit new data as disclosed inFIG. 3(signal S310) or the indication signal (signal S410) as disclosed inFIG. 4.

Communication module920may transmit messages to one or more of network nodes100a-bof the wireless network described inFIG. 1. Communication module920may include a transmitter and/or a transceiver, such as interface111and/or antenna114described above in relation toFIG. 1. Communication module920may include circuitry configured to wirelessly transmit messages and/or signals. In particular embodiments, communication module920may receive messages and/or signals for transmission from determining module910. In certain embodiments, the functions of communication module920described above may be performed in one or more distinct modules.

Receiving module930may perform the receiving functions of wireless device110. In certain embodiments, receiving module930may perform any of the receiving functions of wireless device110described above with respect toFIGS. 1-7. In one example embodiment, receiving module930may receive the adaptive HARQ retransmission request(s) from network node100(e.g., signal S210). Receiving module930may include a receiver and/or a transceiver, such as interface111and/or antenna114described above in relation toFIG. 1. Receiving module930may include circuitry configured to wirelessly receive messages and/or signals. In particular embodiments, receiving module930may communicate received messages and/or signals to determining module910.

Optionally, wireless device110may include input module940. Input module940may receive user input intended for wireless device110. For example, the input module may receive key presses, button presses, touches, swipes, audio signals, video signals, and/or any other appropriate signals. The input module may include one or more keys, buttons, levers, switches, touchscreens, microphones, and/or cameras. The input module may communicate received signals to determining module910.

Optionally, wireless device110may include display module950. Display module950may present signals on a display of wireless device110. Display module950may include the display and/or any appropriate circuitry and hardware configured to present signals on the display. Display module950may receive signals to present on the display from determining module910.

Determining module910, communication module920, receiving module930, input module940, and display module950may include any suitable configuration of hardware and/or software. Wireless device110may include additional modules beyond those shown inFIG. 9that may be responsible for providing any suitable functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the various solutions described herein).

FIG. 10is a block schematic of an exemplary network node100, in accordance with certain embodiments. Network node100may include one or more modules. For example, network node100may include determining module1010, communication module1020, receiving module1030, and any other suitable modules. In some embodiments, one or more of determining module1010, communication module1020, receiving module1030, or any other suitable module may be implemented using one or more processors, such as processor102described above in relation toFIG. 1. In certain embodiments, the functions of two or more of the various modules may be combined into a single module. Network node100may perform one or more steps of the adaptive HARQ retransmission process described above in reference toFIGS. 1-7.

Determining module1010may perform the processing functions of network node100. In certain embodiments, determining module1010may perform any of the functions of network node described above with respect toFIGS. 1-7. In one example embodiment, determining module1010may determine that an uplink transmission from wireless device110was not received. Determining module1010may also determine that network node100did not receive an adaptive HARQ retransmission from wireless device110in response to network node100transmitting an Adaptive HARQ retransmission request. Determining module1010may then determine whether network node100should transmit a subsequent adaptive HARQ retransmission request to wireless device110.

In response to determining that another adaptive HARQ retransmission request should not be sent to wireless device110, determining module1010may stop the scheduling of another adaptive HARQ retransmission request. In some embodiments, determining module1010determines whether to transmit another adaptive HARQ retransmission request by counting a number of adaptive HARQ retransmission requests that have previously been transmitted to wireless device110and determining that another adaptive HARQ retransmission request should not be sent when the number of adaptive HARQ retransmission requests reaches a preconfigured number (e.g., 1, 2, 3, 4, or 5 etc.).

In some embodiments, determining module1010may determine that wireless device110skipped an uplink transmission and no adaptive HARQ retransmission is necessary in response to determining that the preconfigured number of adaptive HARQ retransmissions have been sent to wireless device110.

Determining module1010may include or be included in one or more processors, such as processor102described above in relation toFIG. 1. Determining module1010may include analog and/or digital circuitry configured to perform any of the functions of determining module1010and/or processor102described above. The functions of determining module1010may, in certain embodiments, be performed in one or more distinct modules. For example, in certain embodiments some of the functionality of determining module1010may be performed by an allocation module.

Communication module1020may perform the transmission functions of network node100. In certain embodiments, network node100may perform any of the functions of the node described above with respect toFIGS. 1-7. In one example embodiment, communication module1020may transmit adaptive HARQ retransmission requests to wireless device110. In some embodiments, an adaptive HARQ retransmission request sent from communication module1020may be indicated by addressing the SPS RNTI of wireless device110and/or by setting the NDI to 1 (i.e., indicating that NDI is not toggled).

Communication module1020may transmit messages to one or more of wireless devices110. Communication module1020may include a transmitter and/or a transceiver, such as transceiver1010described above in relation toFIG. 10. Communication module1020may include circuitry configured to wirelessly transmit messages and/or signals. In particular embodiments, communication module1020may receive messages and/or signals for transmission from determining module1010or any other module.

Receiving module1030may perform the receiving functions of network node100. In certain embodiments, receiving module1030may perform any of the functions of network node100described inFIGS. 1-7. In one example embodiment, receiving module1030may receive new data (signal S310) from wireless device110in response to network node100sending an adaptive HARQ retransmissions request (signal S210) to wireless device110. In some embodiments, receiving module1030may receive an indication signal (signal S410) from wireless device110. The indication signal may be transmitted from wireless device110in response to network node100sending an adaptive HARQ retransmissions request (signal210) to wireless device110. Indication signal may comprise any suitable data including new data and/or padding.

Receiving module1030may receive any suitable information from wireless device110Receiving module1030may include a receiver and/or a transceiver, such as interface101and/or antenna104, which are described above in relation toFIG. 1. Receiving module1030may include circuitry configured to wirelessly receive messages and/or signals. In particular embodiments, receiving module1030may communicate received messages and/or signals to determining module1010or any other suitable module.

Determining module1010, communication module1020, and receiving module1030may include any suitable configuration of hardware and/or software. Network node100may include additional modules beyond those shown inFIG. 10that may be responsible for providing any suitable functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the various solutions described herein).

Modifications, additions, or omissions may be made to the systems and apparatuses disclosed herein without departing from the scope of the disclosure. Although the above description and embodiments refer to the handling of adaptive HARQ retransmissions for skipping transmission on SPS resources, the disclosure includes handling adaptive HARQ retransmissions when skip padding is done on dynamically scheduled resources and UL transmission. Furthermore, in some embodiments, wireless device110may be configured to allow non-adaptive HARQ retransmissions on SPS granted resources. In certain embodiments, adaptive HARQ retransmission grants may override non-adaptive HARQ retransmission occasions.

Moreover, the components of the systems and apparatuses may be integrated or separated. The operations of the systems and apparatuses may be performed by more, fewer, or other components. Additionally, operations of the systems and apparatuses may be performed using any suitable logic comprising software, hardware, and/or other logic. As used in this document, “each” refers to each member of a set or each member of a subset of a set.

Any steps described herein are merely illustrative of certain embodiments. It is not required that all embodiments incorporate all the steps disclosed nor that the steps be performed in the exact order depicted or described herein. Furthermore, some embodiments may include steps not illustrated or described herein, including steps inherent to one or more of the steps disclosed herein.

Any appropriate steps, methods, or functions may be performed through one or more functional modules. Each functional module may comprise software, computer programs, sub-routines, libraries, source code, or any other form of executable instructions that are executed by, for example, a processor. In some embodiments, each functional module may be implemented in hardware and/or in software. For example, one or more or all functional modules may be implemented by processors102and/or112, possibly in cooperation with storage103and/or113. Processors102and/or112and storage103and/or113may thus be arranged to allow processors102and/or112to fetch instructions from storage103and/or113and execute the fetched instructions to allow the respective functional module to perform any steps or functions disclosed herein.

Modifications, additions, or omissions may be made to the methods disclosed herein without departing from the scope of the disclosure. The methods may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order. Although this disclosure has been described in terms of certain embodiments, alterations and permutations of the embodiments will be apparent to those skilled in the art. Accordingly, the above description of the embodiments does not constrain this disclosure. Other changes, substitutions, and alterations are possible without departing from the spirit and scope of this disclosure, as defined by the following claims.

Abbreviations used in the preceding description include:

AP Access Point

BS Base Station

BSC Base Station Controller

BTS Base Transceiver Station

C-RNTI Cell Radio Network Temporary Identifier

DAS Distributed Antenna System

eNB evolved Node B

HARQ Hybrid Automatic Repeat Request

LAN Local Area Network

LTE Long Term Evolution

MAC Medium Access Control

MAN Metropolitan Area Network

NDI New Data Indicator

PDCCH Physical Downlink Control Channel

PSTN Public Switched Telephone Network

RNC Radio Network Controller

RRC Radio Resource Control

TTI Transmission Time Interval

UE User Equipment

UL Uplink

WAN Wide Area Network