WO2016041574A1

WO2016041574A1 - Detection of a transmission error in a wireless network

Info

Publication number: WO2016041574A1
Application number: PCT/EP2014/069647
Authority: WO
Inventors: Gustavo Wagner; Frank Frederiksen
Original assignee: Nokia Solutions And Networks Oy
Priority date: 2014-09-16
Filing date: 2014-09-16
Publication date: 2016-03-24

Abstract

An example technique may include controlling receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device, determining, by the first wireless device based on the received data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device, and controlling sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission.

Description

DESCRIPTION

TITLE

DETECTION OF A TRANSMISSION ERROR IN A WIRELESS NETWORK

TECHNICAL FIELD

[0001 ] This description relates to communications.

BACKGROUND

[0002] A communication system may be a facility that enables communication between two or more nodes or devices, such as fixed or mobile communication devices. Signals can be carried on wired or wireless carriers.

[0003] An example of a cellular communication system is an architecture that is being standardized by the 3 Generation Partnership Project (3GPP). A recent development in this field is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. E-UTRA (evolved UMTS Terrestrial Radio Access) is the air interface of 3GPP's Long Term Evolution (LTE) upgrade path for mobile networks. In LTE, base stations, which are referred to as enhanced Node Bs (eNBs), provide wireless access within a coverage area or cell. In LTE, mobile devices, or mobile stations are referred to as user equipments (UE). LTE has included a number of improvements or developments. SUMMARY

[0004] According to an example implementation, a method may include controlling receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device, determining, by the first wireless device based on the received data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device, and controlling sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission.

[0005] According to another example implementation, an apparatus includes at least one processor and at least one memory including computer instructions, when executed by the at least one processor, cause the apparatus to control receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device, determine, by the first wireless device based on the received data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device, and control sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission.

[0006] According to another example implementation, a computer program product includes a computer-readable storage medium and storing executable code that, when executed by at least one data processing apparatus, is configured to cause the at least one data processing apparatus to perform a method including controlling receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device, determining, by the first wireless device based on the received status of the new data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device, and controlling sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission.

[0007] According to another example implementation, an apparatus may include means for controlling receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device, means for determining, by the first wireless device based on the received data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device, and means for controlling sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission.

[0008] According to an example implementation, a method may include determining, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device, providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data, and initiating, by the second protocol entity of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data from the second wireless device.

[0009] According to another example implementation, an apparatus includes at least one processor and at least one memory including computer instructions, when executed by the at least one processor, cause the apparatus to: determine, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device, provide a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data, initiate, by the second protocol entity of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data from the second wireless device. According to another example implementation, a computer program product includes a computer-readable storage medium and storing executable code that, when executed by at least one data processing apparatus, is configured to cause the at least one data processing apparatus to perform a method comprising: determining, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device, providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data, and initiating, by the second protocol entity of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data from the second wireless device.

[0010] According to another example implementation, an apparatus may include means for determining, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device, means for providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data, and means for initiating, by the second protocol entity of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data from the second wireless device.

[0011 ] The details of one or more examples of implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a block diagram of a wireless network 130 according to an example implementation.

[0013] FIG. 2 is a diagram illustrating an example implementation of a user device.

[0014] FIG. 3 is a diagram illustrating a technique for detecting and recovering from an out-of-order transmission or other transmission error according to another example implementation.

[0015] FIG. 4 is a diagram illustrating another technique for detecting and recovering from an out-of-order transmission or other transmission error according to another example implementation.

[0016] FIG. 5 is a flow chart illustrating operation of a wireless device according to an example implementation.

[0017] FIG. 6 is a flow chart illustrating operation of a wireless device according to another example implementation.

[0018] FIG. 7 is a block diagram of a wireless station (e.g., BS or user device or other wireless node) 700 according to an example implementation. DETAILED DESCRIPTION

[0019] According to an example illustrative implementation, a New Data Indicator (NDI) is a field or signal that may be transmitted by a base station (BS) in LTE via the Physical downlink control channel (PDCCH). The timing of the NDI signal identifies the hybrid ARQ (HARQ) process for which the NDI applies. The NDI signal indicates whether the transmitted data unit (transmitted on the data channel) for the corresponding HARQ process is a new data unit (not previously transmitted), or a retransmitted data unit (a retransmission of a previously transmitted data unit). The NDI signal can toggle between values to indicate either a transmission of new data, or a retransmission (of previously transmitted data). According to an example implementation, the NDI signal may be used by a wireless device (such as, for example, a user device or mobile station/MS) to detect out-of order data transmissions or to detect a failure to receive an expected

retransmission from the BS much earlier in the communication process, rather than waiting for the BS to detect this problem.

[0020] In one illustrative example, a wireless device may send a negative acknowledgement (NACK) for a data unit to the BS. After sending this NACK, the wireless device is now expecting the BS to retransmit the NACKed data unit. If a NDI signal for the next transmitted data unit from the BS indicates new data (and thus indicating the requested/expected retransmission did not occur), then this may (or likely) indicates that the BS did not receive the NACK (or some other error has occurred), and the wireless device can take appropriate action to notify the BS of the failure to receive the expected retransmission of the data unit or of the out of order transmission. This is merely one illustrative example, and other types of control signals (other than an NDI signal) may be used. Also, while these illustrative examples are described with respect to LTE, these techniques may be applied to a variety of wireless technologies.

[0021] According to an example implementation, a method may include controlling receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator (e.g., a NDI signal) indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device (e.g., an NDI signal indicating transmission of new data), determining, by the first wireless device based on the received data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device, and controlling sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission.

[0022] According to another example implementation, a method may include determining, by a first protocol entity (e.g., a media access control/MAC entity) of a first wireless device in a wireless network based on a control signal (e.g., based on a NDI signal indicating transmission of new data) received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device, providing a notification, by the first protocol entity (e.g., MAC entity) of the first wireless device to a second protocol entity (e.g., radio link control/RLC entity) of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data, and, initiating, by the second protocol entity (e.g., RLC entity) of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data from the second wireless device.

[0023] FIG. 1 is a block diagram of a wireless network 130 according to an example implementation. In the wireless network 130 of FIG. 1 , user devices 131 , 132, 133 and 135, which may also be referred to as user equipments (UEs), may be connected (and in communication) with a base station (BS) 134, which may also be referred to as an enhanced Node B (eNB). At least part of the functionalities of a base station or eNB may be also be carried out by any node, server or host which may be operably coupled to a transceiver, such as a remote radio head. BS 134 provides wireless coverage within a cell 136, including to user devices 131 , 132, 133 and 135. Although only four user devices are shown as being connected or attached to BS 134, any number of user devices may be provided. BS 134 is also connected to a core network 150 via a S1 interface 151 . This is merely one simple example of a wireless network, and others may be used.

[0024] A user device (user terminal, user equipment (UE)) may refer to a portable computing device that includes wireless mobile communication devices operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: a mobile station, a mobile phone, a cell phone, a smartphone, a personal digital assistant (PDA), a handset, a device using a wireless modem (alarm or

measurement device, etc.), a laptop and/or touch screen computer, a tablet, a phablet, a game console, a notebook, and a multimedia device, as examples. It should be

appreciated that a user device may also be a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network.

[0025] In LTE (as an example), core network 150 may be referred to as Evolved Packet Core (EPC), which may include a mobility management entity (MME) which may handle or assist with mobility/handover of user devices between BSs, one or more gateways that may forward data and control signals between the BSs and packet data networks or the Internet, and other control functions or blocks.

[0026] FIG. 2 is a diagram illustrating an example implementation of a user device. Each user device may include at least one radio protocol stack that may be implemented in hardware and/or software. According to an example implementation, a protocol stack may include logic, and/or computer instructions executed by a processor to perform the functions or operations for each entity of the protocol stack. An example protocol stack for a user device 210 may include, for example, a Packet Data Convergence Protocol (PDCP) entity 240, a Radio Link Control (RLC) entity 242, a Media Access Control (MAC) entity 244, a Physical layer (PHY) entity 246, and a Radio Resource Control (RRC) entity 248.

[0027] The PDCP entity 240 may, for example, perform ciphering (encryption and decryption of data) and header compression-decompression. The RLC entity 242 may, for example, perform segmentation/concatenation, error detection and correction, data retransmission, duplicate detection and in-sequence data delivery to higher layers.

According to an example implementation, there may be one RLC corresponding to one logical channel. MAC entity 244 performs multiplexing of logical channels (where there may be one or more logical channels), hybrid ARQ (HARQ) retransmissions (where ARQ may refer to automatic repeat request), inserting of MAC control elements (MAC CEs) used for in-band control signaling, and other MAC-related functions. The PHY entity 246 handles or performs coding/decoding, modulation/demodulation, multi-antenna mapping, and other physical layer functions. Multiple RLC entities within a user device may share one MAC entity 244 and one PHY entity 246. RRC entity 248 may be responsible for handling a number of functions or procedures related to the Radio Access Network (RAN).

[0028] BS 134 may include the same or a similar structure to that shown in FIG. 2, e.g., including one or more of a Packet Data Convergence Protocol (PDCP) entity 240, a Radio Link Control (RLC) entity 242, a Media Access Control (MAC) entity 244, a Physical layer (PHY) entity 246, and a Radio Resource Control (RRC) entity 248.

[0029] According to an example implementation, the RLC entity 242 of user device 132 (as an example) implements an ARQ process, in which (e.g., for an acknowledged mode) a transmitter (e.g., transmitting BS) retransmits RLC packets (data units) that were negatively acknowledged (or NACKed) by a receiving RLC entity (e.g., receiving RLC entity at user device 132). An acknowledged mode (AM) RLC transmitter has the ability to request a status report from the RLC receiver by sending a poll signal to the RLC receiver. The status report from the RLC receiver may, for example, indicate acknowledgement (ACK) of receipt or negative acknowledgement (NACK) for one or more data units. For example, in an example implementation, an RLC transmitter may send a poll (e.g., by sending a PDU with a polling bit set to 1 ) to obtain a status report when one or more of the following have occurred at the RLC transmitter: a predefined number of data units or bytes have been transmitted, a last data unit in a buffer has been transmitted, or a poll retransmit timer has expired. The RLC transmitter may resend/retransmit any RLC data units indicated as NACKed (negatively acknowledged) in the status report.

[0030] MAC entity 244 at a user device may operate a plurality (e.g., 8) parallel

HARQ (hybrid ARQ) processes, with each HARQ process using, for example, a Stop-And- Wait method. After a transmitting MAC entity transmits a MAC data unit, the receiving MAC entity may respond with an ACK or NACK at a predetermined time, e.g., 4 ms or 4 frames after the original transmitted data unit. The transmitting MAC entity transmits a next data unit after receiving an acknowledgement, and may resend the previous MAC data unit if a NACK is received. However, ACKs/NACKs are sent via the same

channel/medium over which the data is sent. Thus, errors may occur, such as an ACK to NACK error (e.g., in which an ACK is transmitted but is mis-received (or mis-interpreted) as a NACK, or a NACK to ACK error (e.g., in which a NACK is mis-received/mis- interpreted as an ACK). Also, a transmitting MAC entity, e.g., a transmitting MAC entity at a BS, may transmit a new data indicator (NDI) on a downlink control channel, such as on a PDCCH (physical downlink control channel).

[0031] A state of the NDI may indicate whether the BS MAC entity is transmitting a new (not previously transmitted) data unit or retransmitting a (an earlier transmitted) data unit. Thus, a new data unit (sent by a sending device) may refer to a data unit that was not previously sent/transmitted by the sending device, while a retransmitted data unit may refer to a data unit that was earlier (or previously) sent/transmitted by the sending device and is being sent/transmitted again (retransmitted) by the sending device. For example, the sending device may resend/retransmit a data unit where there was a problem at the receiving device that prevented reception/decoding of the data unit or other problem that prevented the sending/transmitting device from receiving an ACK (acknowledgement) that acknowledged receipt of the data unit by the receiving device. According to an example implementation, a BS MAC entity may toggle (or change) the state of the NDI for a HARQ process to indicate that a new data unit is being transmitted on a data channel for the same HARQ process. In an example implementation, each of the 8 HARQ processes may transmit data (over a data channel), ACK/NACKs and a NDI (over a control channel(s)) at a different time, e.g., such that the HARQ process may be implicitly identified for these signals/data based on timing or time of transmission. For example, for a HARQ process, ACK/NACK signals may be transmitted 4 frames (e.g., 4ms) after the original data transmission. In this manner, according to an example implementation, these control signals (e.g., ACK/NACK) may be associated with a HARQ process based on the time or timing of the transmission of these signals. Similarly, an NDI signal may be associated with a data unit or a HARQ process by the NDI signal being transmitted at the same time as or in parallel to the transmission of the data unit, for example.

[0032] According to an example implementation, rather than waiting for a transmitting RLC entity to send a poll (to request a status report), a receiving node (e.g., a user device receiving data from a BS) may detect an out of order transmission of a data unit or other data transmission error. Once an out of order data unit (or other transmission error) has been detected by a user device, the user device may send one or more signals to the transmitting BS to cause the transmitting BS to send (or re-send) the in-order or missing (expected) data unit, to correct the transmission error(s). This may allow data transmission processes (e.g., MAC HARQ process and/or RLC ARQ process) to more quickly detect and/or correct out-of-order transmissions or other transmission errors. Several different example implementations or options may be used for a receiving node (e.g., a user device) to notify a transmitting node (e.g., BS) of a determined out-of-order data unit or other transmission error.

[0033] FIG. 3 is a diagram illustrating a technique for detecting and recovering from an out-of-order transmission or other transmission error according to an example implementation. In FIG. 3, a user device 132 is in communication with a base station (BS) 134. According to an example implementation, at 312, user device 132 (or an RLC entity of user device 132) may receive a RLC data unit K (with a sequence number (SN) = K) from BS 134. Next, at 314, user device 132 (or an RLC entity of user device 132) may receive a RLC data unit K+2 (with sequence number = K+2) from BS 134, which is a data unit that is out-of-order compared to the previously received data unit (SN=K). Thus, at 316, user device 132 determines that the received data unit (at 314) is an out-of-order data unit, e.g., a data unit having a sequence number (K+2) that is out of order compared to the previously (or immediately prior) received data unit at 312 (with SN=K). After receiving the data unit with SN=K (at 312), a next in-order data unit should have a sequence number K+1 , which is the sequence number following the previously received and decoded data unit (SN=K). But the data unit received at 314 is out-of-order because the data unit (SN=K+2) received at 314 does not have a sequence number having a next consecutive sequence number after the most recently received (and decoded) data unit (SN=K). For example, receipt of an out-of-order data unit may, at least in some situations, be an indication that the missing data unit(s) (e.g., data unit with SN=K+1 in this example) was mis-delivered, not decoded correctly, or otherwise not received by user device 132. According to an example implementation, rather than waiting for BS 134 to take action, user device 132 may send one or more signals to BS 134 flagging (or indicating) a transmission error, such as flagging or indicating the detection by user device 132 of an out-of-order data unit. The BS 134 may then, for example, assess the situation, investigate which data units have been sent and/or acknowledged, and/or resend one or more data units. In this manner, the user device 132 and BS 134 may, at least in some situations, more quickly detect and correct (or recover from) an out-of-order transmission or other transmission error.

[0034] Various signals may be used to indicate to BS 134 that an out-of-order data unit was detected or received. According to one example implementation, user device 132 may indicate to BS 134 that an out-of-order data unit was received or detected by user device 132 sending (or controlling sending) a retransmission failure indication (not shown in FIG. 3) for a hybrid ARQ (HARQ) process indicating a failure of the user device to receive an expected retransmission of a data unit from the BS 134 based on a status of a new data indicator (NDI) for the HARQ process indicating transmission of a new data unit. For example, the transmission of a new data unit may be considered an out-of-order data unit when the user device 132 is expecting a retransmission of the current/previous data unit. For example, a status of the new data indicator (NDI) from the BS 134 may identify this out-of-order transmission by indicating a transmission of a new data unit, when the user device sent a NACK for a data unit and is now expecting a retransmission of that data unit, for example. An example of this situation is described with reference to FIG. 4.

[0035] According to another example implementation, user device 132 and BS 134 may perform a set of operations 317 (which may include one or more of operations 318, 320 and 322, as examples). In this example implementation, at 318, user device 132 sends an out-of-order indication to BS 134 to indicate that an out-of-order data unit (e.g., data unit with SN=K+2) was received by the user device 132. For example, the out-of- order indication may be a flag or bit (or bits) that may be sent, e.g., via a control channel. In an example implementation, the out-of-order indication may be a physical layer signaling (e.g., one bit), e.g., which may be set to 0 by a user device 132 if RLC packets are received in order by user device 132, and set to 1 if user device 132 received an out- of-order packet or data unit.

[0036] In one example implementation, the out-of-order indication may cause a higher layer function or program at the BS 134 to investigate which packets or data units are missing (e.g., sent but not yet acknowledged). In yet another example

implementation, multiple time-dependent channels (e.g., different time slots) may be used to transmit a different out-of-order indication. For example, a time-related dependency of the out-of-order indication to identify the missing data unit (e.g., RLC data unit). For example, four resources (e.g., channels, frequencies, time slots...) may be used to communicate an out-of-order indication to a BS 134. User device 132 may be allowed to indicate on, then depending on the exact time of observing the missing RLC data unit (or the time of observing the out-of-order data unit), the user device may identify the missing RLC sequence number or index on the time-dependent resource. One non-limiting example of identifying the RLC sequence number on the time-dependent resource, may include that a user device or UE may indicate, on a user device-specific transmission resource, that a RLC packet is missing. Under the assumption of constant or more correctly known processing time in the receiving end, the base station (or eNB) knows at which time instant the original transmission happened, and it will be able to identify which

RLC packet or RLC packets failed.

[0037] In another non-limiting example, the time-dependent resources may be combined with multiple user device-specific resources (or channels) in the frequency or code domain to allow for the possibility to indicate a derivative or mapping of the missing RLC packet number (for instance mapping through the modulus operation).

[0038] The time-dependent resource for potential indication may, in some implementations, be defined such that the resources are only available in certain time instants, such that different user devices will have different time frames available for the potential indication of missing RLC packet numbers.

[0039] In one example implementation, diversity may be applied for the transmission of the out-of-order indication, with respect to ACK/NACK control signals for the same data unit. For example, user device 132 may send the out-of-order indication via a resource that is different than a resource used for a transmission of an

acknowledgement/negative acknowledgement of the missing data unit or out-of-order data unit. As some examples, a different code, a different channel or frequency, or a different transmission time interval (TTI) may be used to transmit the out-of-order indication than what is used to transmit ACK/NACK information regarding the same data unit.

[0040] Referring to FIG. 3 again, after transmitting the out-of-order indication at 318, the BS 134 may send a poll at 320 to the user device 132. In response to the poll, the user device may send an RLC status report that may include ACK (acknowledgement) or NACK (negative acknowledgement) for one or more data units, including a NACK for the missing data unit(s).

[0041 ] According to an example implementation, in response to receiving the status report, the BS 134 may take corrective action, such as resending the missing RLC data unit at 328.

[0042] In another example implementation, the user device 132 and BS 134 may perform a set of operations 323, including operations 324 and 326 in response to determining or receiving an out-of-order data unit at 316. At 324, for example, in response to determining that an out-of-order data unit has been received, the user device 132 may obtain uplink resources from the BS 134. At 326, the user device 132 may then send an RLC status report to the BS 134 including a NACK for the missing data unit(s). At 328, BS 134 may then send the missing data unit (the data unit indicated as NACK in the status report). Therefore, the sending of the unsolicited status report at operation 326 in response to determining that an out-of-order data unit has been received may, at least in some cases, allow for a faster recovery from the out-of-order condition as compared to the set of operations 317 that waits to receive a poll from the BS 134 before sending the status report.

[0043] In one example implementation, a BS 134 may receive an ACK from the user device (which was a NACK misinterpreted as an ACK), and in a later transmission time interval (TTI), the BS 134 receives information that the user device 132 has received a data unit out-of-order. In this example case, depending on network load and latency requirements, for example, several correction options may be used or performed by BS 134, such as, for example: resend the missing data unit on the same HARQ process, e.g., as if the BS 134 had received a NACK in the HARQ signaling; resend the missing data unit on another HARQ process; set the polling bit (or poll) to true in the transmission of the next RLC data unit such that the user device will generate and send a status report to the BS 134; and re-concatenate or re-segment the lost/missing RLC data unit and resend it.

[0044] According to an example implementation, some restrictions may be applied on how RLC data units (e.g., RLC packets, RLC protocol data units) are mapped to physical (PHY) or MAC data units for transmission. According to an example

implementation, either segmentation or concatenation may be applied to RLC data units when mapping RLC data units to PHY (or MAC) data units, but not both segmentation and concatenation of RLC data units may be used for one PHY (or MAC) data unit.

[0045] For example, segmentation may include mapping (for transmission) a segment (or fragment) of one or more RLC data units to a single PHY (or single MAC) data unit. Concatenation may include combining all or part of two or more RLC data units into one PHY (or one MAC) data unit for transmission. For example, an 1800 byte RLC data unit may be segmented (or fragmented) to use a 1000 byte PHY data unit (e.g., based on the available wireless transmission opportunity). Thus, in this segmentation example, the first 1000 bytes of the 1800 byte RLC data unit may be mapped to the 1000 byte PHY (or MAC) data unit for transmission. The remaining 800 bytes of the RLC data unit may be mapped to a second PHY (or a second MAC) data unit.

[0046] However, according to an example implementation, a RLC data unit segment/fragment of a first RLC data unit may not be concatenated with a RLC data unit (or RLC data unit fragment) of one or more other RLC data units into one PHY (or one MAC) data unit (this would be an example where both segmentation and concatenation have been performed). Therefore, according to an example implementation, a segment of an RLC data unit may be mapped to a PHY (or MAC) data unit, but may not be combined (concatenated) with another RLC data unit (or fragment thereof). Similarly, according to this example implementation, only integer (whole RLC data units) numbers of RLC data units may be concatenated into one PHY (or one MAC) data unit, but segments (less than whole RLC data units) may not be concatenated into a PHY (or a MAC) data unit.

[0047] According to an example implementation, by limiting the mapping of RLC data units to PHY (or MAC) data units to allow either segmentation of RLC data units or concatenation of whole (or integer numbers of) RLC data units to a PHY (or MAC) data unit, but not both segmentation and concatenation for the same (or one) PHY (or MAC) data unit, this may allow a more accurate mapping between MAC or PHY data units and RLC data units. Thus, for example, when a NDI for a MAC HARQ process indicates a new data transmission when a receiver may be expecting a retransmission of a MAC data unit, the receiving node or receiving user device 132 may determine a failure to receive an expected retransmission of data unit K based on the NDI signal (indicating transmission of a new MAC data unit K+1 ) and the time/timing of the transmission of the NDI signal (e.g., implicitly identifying the HARQ process), as shown by operation 322.

[0048] By, for example, limiting the mapping from RLC data units to PHY (or MAC) data units to allow either segmentation or whole RLC data unit concatenation, but not both segmentation and concatenation for a PHY (or MAC) data unit, the MAC data unit K that was identified as missing (or failure to receive retransmission) based on the NDI, may be more quickly or more accurately mapped to one or more corresponding or associated RLC data units. In an example implementation, this limitation or restriction on mapping of RLC data units to MAC or PHY data units (not allowing both segmentation and concatenation) for one MAC or PHY data unit may improve communication or signals between RLC, MAC and/or PHY entities at a wireless node (BS or user device), e.g., to allow the HARQ and/or ARQ processes to more quickly recover from out of order errors, retransmission errors, or other transmission errors, by facilitating the communication between a RLC entity and a MAC entity or PHY entity to map a missing MAC or PHY data unit to one or more corresponding RLC data units. This may allow the existing NDI signal or a retransmission failure indication (see FIG. 4 below) provided at the MAC or PHY level, to be used to identify a retransmission error for a MAC or PHY data unit, and then to map this MAC or PHY data unit to a corresponding RLC data unit to allow, for example, existing RLC poll and/or RLC status reports to be used to allow faster recovery from such a transmission error. Also, by respecting boundaries of RLC data units (where both segmentation and concatenation of RLC data units is not allowed or not performed), a RLC transmitter may better correlate signals of different levels or entities, such as ARQ (RLC ARQ) feedback, the HARQ ACK/NACK signals, and/or other signals (NDI signals, retransmission failure indications, status reports, etc.) in order to identify missing data units and/or take appropriate corrective measures (e.g., resend any missing data units).

[0049] FIG. 4 is a diagram illustrating a technique for detecting and recovering from an out-of-order transmission or other transmission error according to another example implementation. As shown in FIG. 4, a user device 132 is in communication with a BS 134. At 412, a HARQ process at BS 134 sends a MAC data unit K to user device 132. The MAC data unit K may include, for example, a HARQ ID to identify the HARQ process, and a user device identifier, such as a cell radio network temporary identifier (C-

RNTI) identifying user device 132, and data. However, in this example, at 413, the user device 132 is unable to decode the MAC data unit K, e.g., due to noise, multi-path interference or other condition.

[0050] At 414, user device 132 sends a NACK (negative acknowledgement) associated with the HARQ process to BS 134. According to an example implementation, the NACK may be associated with the specific HARQ process based on the time or timing of the transmission of the NACK, e.g., NACK may typically be sent 4 frames or 4 ms after the HARQ data unit is sent, according to one example implementation. In this example, at 416, a NACK to ACK error may occur at the BS 134, e.g., such that the BS 134

misinterprets the transmitted NACK as an ACK (acknowledgement) for MAC data unit K.

[0051 ] As a result of BS 134 misinterpreting the NACK at 414 as an ACK for data unit K (or for the associated HARQ process), the BS 134 does not (at this point) resend/retransmit MAC data unit K to user device 132. Rather, at 420, the HARQ process at BS 134 sends a next MAC data unit K+1 , which is a new transmission (not a

retransmission). At 418, e.g., at around the same time that data unit K+1 is transmitted (or in parallel to transmission of data unit K+1 ), BS 134 also transmits control information (e.g., via downlink control channel) to the user device 132 including a new data indicator (NDI) that is toggled (or changed states as compared to the previous data unit

transmission for the same HARQ process) to indicate that the current data transmission (data unit K+1 ) is a new data unit, not a retransmission.

[0052] At 422, the user device 132 determines a failure to receive an expected retransmission of data unit K, based on NDI indicating a new transmission or transmission of a new data unit (and not a retransmission). In other words, for example, due to the stop-and-wait method of the HARQ process (e.g., transmitting one data unit, and waiting for an ACK before transmitting a next data unit, and retransmitting the data unit if a NACK is received), the NDI indicating a transmission of a new data unit means that the HARQ process at BS 134 is not (at this point) retransmitting data unit K, since the HARQ process has moved on to transmit new (or next) data unit K+1 . User device 132 may have several options in responding to the detection of the failure to receive an expected retransmission of a data unit, including a set of operations 423, and as an alternative, a set of operations

431 .

[0053] One example set of operations 423 will be described which may include one or more of operations 424, 426 and 430. At 424, in response to determining the failure to receive the expected retransmission of data unit K, user device 132 may transmit a retransmission failure indication (e.g., indicating that a retransmission of a data unit was requested, but failed/was not received) over a control channel to BS 134. The

retransmission failure indication at 424 may explicitly identify the HARQ process for which the retransmission failure indicates is associated with (or is applied to) by including a HARQ ID field to identify the HARQ process. Alternatively, the HARQ process may be implicitly identified for the retransmission failure indication based on the time or timing for transmitting/sending the retransmission failure indication. For example, the

retransmission failure indication may be transmitted at a fixed time offset from the original data transmission, e.g., 4 frames or 4 ms after the original data transmission of MAC data unit K, for example.

[0054] At 426, in response to receiving the retransmission failure indication for the HARQ process, BS 134 (or RLC entity of BS 134) may send a poll (or polling signal) to user device 132 (or to RLC entity of user device 132). At 428, user device 132 may map the failed or missing MAC data unit (e.g., MAC data unit K) (for which the retransmission failure was determined) to one or more associated RLC data units.

[0055] At 430, in response to receiving the poll at 426, user device 132 may send a status report (e.g., RLC status report) with a NACK indicated for the data unit K for which a failure to receive the expected retransmission was determined. Thus, in one example implementation the NACK may be indicated at the MAC level, e.g., NACK indicated for the MAC data unit K. In another example implementation, the status report may include a NACK for an RLC data unit corresponding to or associated with the failed MAC data unit K (determined failure to retransmit data unit K), e.g., based on the mapping performed at 428, for example. At 436, in response to the status report, the BS 134 (e.g., RLC entity at BS 134) may retransmit the RLC data unit or the MAC data unit for which a NACK was indicated in the status report.

[0056] Another example set of operations 431 will be described which may include one or more of operations 432 and 434 in FIG. 4. Thus, for example, operations 432 and 434 may be performed as an alternative to operations 424, 426 and 430. At operation 432, in response to determining a failure to receive an expected retransmission of data unit K, e.g., based on the NDI, the user device may obtain uplink resources from the BS 134. Resources may be obtained by user device sending a request for uplink resources to BS 134, and then a schedule (indicating uplink resources have been allocated for user device 132) being sent from BS 134 to user device 132. At 434, user device 132 may send a status report (e.g., RLC status report) that may include ACK or NACK indications for one or more data units, including a NACK indicated for the data unit K for which a failure to receive the expected transmission was determined. Thus, in one example implementation the NACK may be indicated at the MAC level, e.g., NACK indicated for the MAC data unit K. In another example implementation, the status report may include a

NACK for an RLC data unit corresponding to or associated with the failed MAC data unit K (determined failure to retransmit data unit K), e.g., based on the mapping performed at 428, for example. At 436, in response to the status report, the MAC data unit K (and/or the RLC data unit indicated as NACK in the status report) is resent from BS 134 to user device 132.

[0057] According to an example implementation, the set of operations 431 (including operations 432 and 434) may allow for a faster recovery from a transmission error, as compared to the set of operations 423 (that includes operations 424, 426 and 430), because in the operations 432 and 434, an unsolicited status report is immediately sent to the BS 134, rather than waiting for a poll and then sending the status report.

[0058] According to an example implementation, upon the reception of retransmission failure indication at 424, the BS 134 may decide to concatenate and/or segment the missing data unit(s) in a way which is different than the original data transmission. The retransmission may be performed via one or more HARQ processes which may be different than the HARQ process used to originally send/transmit the data unit(s). Furthermore, RLC sequence numbers may refer to RLC protocol data units

(PDUs), RLC service data units (SDUs), bytes, bits, nibbles or words, for example. Also, according to an example implementation, user device 132 may pass the out-of-order data to upper layers at the user device, and may indicate to upper layer(s) that the missing data/bytes are still expected to be received over the radio interface from BS 134. By passing out-of-order data units to upper layers at the user device, while the user device may await a retransmission of a missing data unit, the user device may address a problem of a user device accumulating a large number of bytes/large amount of data while waiting for missing data to be received, before passing the data to upper layers. Typically, when the in-order delivery is finally possible at the user device, the RLC entity of a user device, may then pass a huge amount of data to the upper layers, e.g., to the TCP/IP

(Transmission Control Protocol/Internet Protocol) stack of the user device. For example, in such a case, the TCP/IP stack at the user device 132 may have a relatively large amount of data to process at once, and as a result, the connection speed or connection performance may be reduced or slowed, e.g., based on a processing delay at the user device. Therefore, to improve the data processing speed at the user device, the user device may pass at least some out-of-order data to an upper layer (e.g., TCP/IP layers) of the user device, which may speed connection processing at the user device, for example.

[0059] According to an example implementation, the operation at 422 may include the following. At 422, a media access control (MAC) entity 244 of a wireless device (such of user device 132) may determine, based on a control signal (e.g., NDI received at 418) received from another wireless device (such as from the BS 134), a failure to receive an expected retransmission of a data unit from the second wireless device. Also, according to an example implementation, MAC entity 244 of user device 132 may then provide a notification to (or notify) a radio link control (RLC) entity 242 of the failure (e.g., by the MAC entity 244) to receive the expected retransmission of the data unit. The notification provided by the MAC entity 244 of the failure to receive the expected retransmission may include, for example: a HARQ ID to identify the hybrid ARQ process for which the expected retransmission was not received (based on the status of the NDI for the HARQ process). Also, the RLC entity 242 may map the HARQ ID to a RLC sequence number of a next expected RLC data unit (or may identify a next in-order RLC data unit, for example. For example, for a HARQ process, the RLC entity 242 may have received RLC data unit K-1 , and RLC data unit K has not yet been received. Thus, based on the MAC entity 242 of user device 132 providing the notification to RLC entity 242 of user device 132 of the failure (of the MAC entity 244) to receive an expected retransmission of a data unit for the HARQ process (e.g., based on a status of the NDI for the HARQ process), the RLC entity 242 may perform one or more actions, e.g., to notify the BS 134 of the failure to receive the data unit.

[0060] For example, the user device 132 may initiate a communication process with the base station 134 to receive the data unit (the data unit for which there was the failure to receive the expected retransmission) from the BS 134. For example, the user device may send a message to BS 134 indicating that the data unit K (or data unit for which a failure to receive the expected retransmission was determined) has not been received by user device 132. Also, as another example, operations 424, 426, 428 and 430 may be performed, or for example, operations 432 and 434 may be performed, e.g., to notify the BS 134 of the missing data unit or of the data unit for which the user device failed to receive. The missing data unit may be received at 436.

[0061] In FIGs. 3 and 4, the communication is performed between devices 132 and 134. In the illustrative examples shown in FIGs. 3 and 4, device 132 is a user device, and device 134 is a base station. Although not shown in FIGs. 3 and 4, the

communications and operations performed in FIGs. 3 and 4 may alternatively be performed between a first user device and a second user device (e.g., between peer user devices), between a first base station and a second base station, or between a user device (at device 134) and a base station (at device 132), as examples.

[0062] FIG. 5 is a flow chart illustrating operation of a wireless device according to an example implementation. Operation 510 includes controlling receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device. Operation 520 includes determining, by the first wireless device based on the received data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device. Operation 530 includes controlling sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission. [0063] According to another example implementation of the method of FIG. 5, the first wireless device and the second wireless device may be one of the following: the first wireless device is a user device and the second wireless device is a user device; the first wireless device is a base station and the second wireless device is a base station; the first wireless device is a user device and the second wireless device is a base station; and the first wireless device is a base station and the second wireless device is a user device.

[0064] According to another example implementation of the method of FIG. 5, the data indicator may include a new data indicator that is provided for a hybrid ARQ process, wherein the determining may include determining, by the first wireless device based on the received new data indicator for the hybrid ARQ process, a failure to receive an expected retransmission of a data unit from the second wireless device.

[0065] According to another example implementation of the method of FIG. 5, the determining may include: determining, by the first wireless device, a failure to decode a first transmission of the data unit from the second wireless device for a hybrid ARQ process, controlling sending, by the first wireless device, a negative acknowledgement to the second wireless device based on the failure to decode the first transmission of the data unit, and determining, by the first wireless device, a failure to receive an expected retransmission of the data unit from the second wireless device for the hybrid ARQ process based on the data indicator for the hybrid ARQ process that indicates a transmission of data from the second wireless device that was not previously transmitted from the second wireless device.

[0066] According to another example implementation of the method of FIG. 5, the method may further include controlling receiving a poll by the first wireless device from the second wireless device, and controlling sending, by the first wireless device in response to receiving the poll, a status report to the second wireless device, the status report indicating a status of acknowledgement or negative acknowledgement for one or more data units including a status of negative acknowledgement of the data unit for which a failure to receive an expected retransmission was determined.

[0067] According to another example implementation of the method of FIG. 5, the data indicator is provided for a hybrid ARQ process, and wherein the controlling sending a signal may include controlling sending, by the first wireless device to the second wireless device based on the determining, a retransmission failure indication for the hybrid ARQ process indicating a failure to receive an expected retransmission of a data unit from the second wireless device for the hybrid ARQ process.

[0068] According to another example implementation of the method of FIG. 5, the data indicator may include a new data indicator that is provided for a hybrid ARQ process, and wherein the retransmission failure indication is sent via a resource associated with the first wireless device and at a time that identifies the hybrid ARQ process.

[0069] According to another example implementation of the method of FIG. 5, the controlling sending a signal may include: obtaining, by the first wireless device from the second wireless device, uplink resources, and controlling sending, by the first wireless device, a status report to the second wireless device via the obtained uplink resources, the status report indicating a status of acknowledgement or negative acknowledgement for one or more data units including a status of negative acknowledgement of the data unit for which a failure to receive an expected retransmission was determined.

[0070] According to another example implementation of the method of FIG. 5, the data indicator may include a new data indicator that is provided for a hybrid ARQ process, and further wherein the controlling sending a signal may include: a media access control (MAC) entity of the first wireless device notifying a radio link control (RLC) entity of the first wireless device of the determined failure to receive an expected retransmission of the data unit for the hybrid ARQ process, mapping, by the first wireless device, the data unit of the hybrid ARQ process for which a failure to receive an expected retransmission was determined to one or more associated RLC data units, and obtaining, by the first wireless device from the second wireless device, uplink resources, and controlling sending a RLC status report from the first wireless device to the second wireless device via the obtained uplink resources, the status report indicating a status of acknowledgement or negative acknowledgement for one or more data units including a status of negative

acknowledgement of the one or more associated RLC data units.

[0071 ] According to another example implementation of the method of FIG. 5, the method may further include applying a restriction for transmission of data units between the first wireless device and the second wireless device wherein radio link control (RLC) data units may be segmented or concatenated for transmission in a physical data unit, but RLC data units may not be both segmented and concatenated for transmission in a physical data unit.

[0072] According to another example implementation a computer program product for a computer may include software code portions for performing the operations or steps of described or claimed herein when the product is run on the computer.

[0073] According to another example implementation, an apparatus may include at least one processor and at least one memory including computer instructions, when executed by the at least one processor, cause the apparatus to: control receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device, determine, by the first wireless device based on the received data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device, control sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission.

[0074] According to an example implementation, a computer program product includes a computer-readable storage medium and storing executable code that, when executed by at least one data processing apparatus, is configured to cause the at least one data processing apparatus to perform a method of FIG. 5, such as including:

controlling receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device, determining, by the first wireless device based on the received status of the new data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device, and controlling sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission.

[0075] FIG. 6 is a flow chart illustrating operation of a wireless device according to another example implementation. Operation 610 includes determining, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device. Operation 620 includes providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected

retransmission of the previously transmitted data. And, operation 630 includes initiating, by the second protocol entity of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data from the second wireless device.

[0076] According to another example implementation of the method of FIG. 6, the control signal may include a new data indicator for a hybrid ARQ process, the new data indicator received via a control channel and indicating whether a data transmission received by the first wireless device from the second wireless device via a data channel is a transmission of new data or a retransmission of previously transmitted data.

[0077] According to another example implementation of the method of FIG. 6, the first wireless device and the second wireless device may be one of the following: the first wireless device is a user device and the second wireless device is a user device; the first wireless device is a base station and the second wireless device is a base station; the first wireless device is a user device and the second wireless device is a base station; and the first wireless device is a base station and the second wireless device is a user device.

[0078] According to another example implementation of the method of FIG. 6, the first protocol entity may include a media access control (MAC) entity, and the second protocol entity may include a radio link control (RLC) entity.

[0079] According to another example implementation of the method of FIG. 6, the control signal may include a new data indicator for a hybrid ARQ process, wherein the providing a notification may include providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data unit, wherein the notification includes information identifying the hybrid ARQ process.

[0080] According to another example implementation of the method of FIG. 6, the control signal may include a new data indicator for a hybrid ARQ process, and wherein the initiating, by the second protocol data unit of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data unit from the second wireless device may include one or more of the following: controlling sending, from the first wireless device to the second wireless device, information identifying a sequence number last received by the first wireless device; controlling sending, from the first wireless device to the second wireless device, a retransmission failure indication, the retransmission failure indication identifying either the hybrid ARQ process or a sequence number; controlling sending, from the first wireless device to the second wireless device, an out-of-order indication to indicate that the first wireless device has received an out-of-order data unit; and controlling sending, from the first wireless device to the second wireless device, a radio link control status report with a negative acknowledgement indicated for the previously transmitted data.

[0081 ] According to another example implementation of the method of FIG. 6, the initiating is performed by the second protocol entity to receive the data unit only for up to a maximum number of the notifications received from the first protocol data unit indicating a failure to receive the expected retransmission of the previously transmitted data unit.

[0082] According to another example implementation of the method of FIG. 6, the method may further include passing out-of-order data from the second protocol entity of the first wireless device to a third protocol entity of the first wireless device while the first wireless device waits to receive the previously transmitted (or missing) data from the second wireless device, the third protocol entity being provided at a higher protocol layer than the second protocol entity.

[0083] According to another example implementation, a computer program product is provided for a computer, and may include software code portions for performing the steps or operations as described above, when the product is run on the computer.

[0084] According to another example implementation, an apparatus may include at least one processor and at least one memory including computer instructions, when executed by the at least one processor, cause the apparatus to: determine, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device, provide a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data, and initiate, by the second protocol entity of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data.

[0085] According to another example implementation, a computer program product includes a computer-readable storage medium and storing executable code that, when executed by at least one data processing apparatus, is configured to cause the at least one data processing apparatus to perform a method of FIG. 6, such as including: determining, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device, providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected

retransmission of the previously transmitted data, and initiating, by the second protocol entity of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data.

[0086] FIG. 7 is a block diagram of a wireless station (e.g., BS or user device) 700 according to an example implementation. The wireless station 700 may include, for example, two RF (radio frequency) or wireless transceivers 702A, 702B, where each wireless transceiver includes a transmitter to transmit signals and a receiver to receive signals. The wireless station also includes a processor or control unit/entity (controller) 704 to execute instructions or software and control transmission and receptions of signals, and a memory 706 to store data and/or instructions. [0087] Processor 704 may also make decisions or determinations, generate frames, packets or messages for transmission, decode received frames or messages for further processing, and other tasks or functions described herein. Processor 704, which may be a baseband processor, for example, may generate messages, packets, frames or other signals for transmission via wireless transceiver 702 (702A or 702B). Processor 704 may control transmission of signals or messages over a wireless network, and may control the reception of signals or messages, etc., via a wireless network (e.g., after being down- converted by wireless transceiver 702, for example). Processor 704 may be

programmable and capable of executing software or other instructions stored in memory or on other computer media to perform the various tasks and functions described above, such as one or more of the tasks or methods described above. Processor 704 may be (or may include), for example, hardware, programmable logic, a programmable processor that executes software or firmware, and/or any combination of these. Using other terminology, processor 704 and transceiver 702 together may be considered as a wireless

transmitter/receiver system, for example.

[0088] In addition, referring to FIG. 7, a controller (or processor) 708 may execute software and instructions, and may provide overall control for the station 700, and may provide control for other systems not shown in FIG. 7, such as controlling input/output devices (e.g., display, keypad), and/or may execute software for one or more applications that may be provided on wireless station 700, such as, for example, an email program, audio/video applications, a word processor, a Voice over IP application, or other application or software.

[0089] In addition, a storage medium (such as, for example, memory 706) may be provided that includes stored instructions, which when executed by a controller or processor may result in the processor 704, or other controller or processor, performing one or more of the functions or tasks described herein and/or claimed herein.

[0090] According to another example implementation, RF or wireless

transceiver(s) 702A/702B may receive signals or data and/or transmit or send signals or data. Processor 704 (and possibly transceivers 702A/702B) may control the RF or wireless transceiver 702A or 702B to receive, send, broadcast or transmit signals or data.

[0091] According to another example implementation, an apparatus may include means (704, and/or 702A/702B) for controlling receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device, means (704, and/or 702A/702B) for determining, by the first wireless device based on the received data indicator, a failure to receive an expected

retransmission of a data unit from the second wireless device, and means (704, and/or 702A/702B) for controlling sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected

retransmission.

[0092] According to another example implementation, the data indicator may include a new data indicator that is provided for a hybrid ARQ process, wherein the means for determining may include means (704, and/or 702A/702B) for determining, by the first wireless device based on the received new data indicator for the hybrid ARQ process, a failure to receive an expected retransmission of a data unit from the second wireless device.

[0093] According to another example implementation, the means for determining may include: means (704, and/or 702A/702B) for determining, by the first wireless device, a failure to decode a first transmission of the data unit from the second wireless device for a hybrid ARQ process, means (704, and/or 702A/702B) for controlling sending, by the first wireless device, a negative acknowledgement to the second wireless device based on the failure to decode the first transmission of the data unit, and means (704, and/or

702A/702B) for determining, by the first wireless device, a failure to receive an expected retransmission of the data unit from the second wireless device for the hybrid ARQ process based on the data indicator for the hybrid ARQ process that indicates a transmission of data from the second wireless device that was not previously transmitted from the second wireless device.

[0094] According to another example implementation the apparatus may further include means (704, and/or 702A/702B) for controlling receiving a poll by the first wireless device from the second wireless device, and means (704, and/or 702A/702B) for controlling sending, by the first wireless device in response to receiving the poll, a status report to the second wireless device, the status report indicating a status of

acknowledgement or negative acknowledgement for one or more data units including a status of negative acknowledgement of the data unit for which a failure to receive an expected retransmission was determined.

[0095] According to another example implementation, the data indicator is provided for a hybrid ARQ process, and wherein the means for controlling sending a signal may include means (704, and/or 702A/702B) for controlling sending, by the first wireless device to the second wireless device based on the determining, a retransmission failure indication for the hybrid ARQ process indicating a failure to receive an expected retransmission of a data unit from the second wireless device for the hybrid ARQ process. [0096] According to another example implementation, the data indicator may include a new data indicator that is provided for a hybrid ARQ process, and wherein the retransmission failure indication is sent via a resource associated with the first wireless device and at a time that identifies the hybrid ARQ process.

[0097] According to another example implementation, the means for controlling sending a signal may include: means (704, and/or 702A/702B) for obtaining, by the first wireless device from the second wireless device, uplink resources, and means (704, and/or 702A/702B) for controlling sending, by the first wireless device, a status report to the second wireless device via the obtained uplink resources, the status report indicating a status of acknowledgement or negative acknowledgement for one or more data units including a status of negative acknowledgement of the data unit for which a failure to receive an expected retransmission was determined.

[0098] According to another example implementation, the data indicator may include a new data indicator that is provided for a hybrid ARQ process, and further wherein the means for controlling sending a signal may include: a media access control (MAC) entity of the first wireless device notifying a radio link control (RLC) entity of the first wireless device of the determined failure to receive an expected retransmission of the data unit for the hybrid ARQ process, means (704) for mapping, by the first wireless device, the data unit of the hybrid ARQ process for which a failure to receive an expected

retransmission was determined to one or more associated RLC data units, means (704, and/or 702A/702B) for obtaining, by the first wireless device from the second wireless device, uplink resources, and means (704, and/or 702A/702B) for controlling sending a RLC status report from the first wireless device to the second wireless device via the obtained uplink resources, the status report indicating a status of acknowledgement or negative acknowledgement for one or more data units including a status of negative acknowledgement of the one or more associated RLC data units.

[0099] According to another example implementation, the apparatus may further include means (704, and/or 702A/702B) for applying a restriction for transmission of data units between the first wireless device and the second wireless device wherein radio link control (RLC) data units may be segmented or concatenated for transmission in a physical data unit, but RLC data units may not be both segmented and concatenated for transmission in a physical data unit.

[00100] According to another example implementation, an apparatus may include means (704, and/or 702A/702B) for determining, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device, means (704, and/or 702A/702B) for providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data, and means (704, and/or 702A/702B) for initiating, by the second protocol entity of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data.

[00101] According to an example implementation, the control signal may include a new data indicator for a hybrid ARQ process, the new data indicator received via a control channel and indicating whether a data transmission received by the first wireless device from the second wireless device via a data channel is a transmission of new data or a retransmission of previously transmitted data.

[00102] According to another example implementation, first wireless device and the second wireless device may be one of the following: the first wireless device is a user device and the second wireless device is a user device; the first wireless device is a base station and the second wireless device is a base station; the first wireless device is a user device and the second wireless device is a base station; and the first wireless device is a base station and the second wireless device is a user device.

[00103] According to an example implementation, the first protocol entity may include a media access control entity, and the second protocol entity comprises a radio link control entity.

[00104] According to an example implementation, the control signal may include a new data indicator for a hybrid ARQ process, wherein the means for providing a notification may include: means (704, and/or 702A/702B) for providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data unit, wherein the notification includes information identifying the hybrid ARQ process.

[00105] According to an example implementation, the control signal may include a new data indicator for a hybrid ARQ process, and wherein the means for initiating, by the second protocol data unit of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data unit from the second wireless device may include one or more of the following: means (704, and/or

702A/702B) for controlling sending, from the first wireless device to the second wireless device, information identifying a sequence number last received by the first wireless device, means (704, and/or 702A/702B) for controlling sending, from the first wireless device to the second wireless device, a retransmission failure indication, the

retransmission failure indication identifying either the hybrid ARQ process or a sequence number, means (704, and/or 702A/702B) for controlling sending, from the first wireless device to the second wireless device, an out-of-order indication to indicate that the first wireless device has received an out-of-order data unit; and means (704, and/or

702A/702B) for controlling sending, from the first wireless device to the second wireless device, a radio link control status report with a negative acknowledgement indicated for the previously transmitted data.

[00106] According to an example implementation, the means for initiating may include the second protocol entity receiving the data unit only for up to a maximum number of the notifications received from the first protocol data unit indicating a failure to receive the expected retransmission of the previously transmitted data unit.

[00107] Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Implementations may implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, a data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. Implementations may also be provided on a computer readable medium or computer readable storage medium, which may be a non-transitory medium. Implementations of the various techniques may also include implementations provided via transitory signals or media, and/or programs and/or software implementations that are downloadable via the Internet or other network(s), either wired networks and/or wireless networks. In addition, implementations may be provided via machine type communications (MTC), and also via an Internet of Things (IOT).

[00108] The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, photoelectrical and/or electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst a number of computers.

[00109] Furthermore, implementations of the various techniques described herein may use a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the implementation and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors microcontrollers, ...) embedded in physical objects at different locations.

Mobile cyber physical systems, in which the physical system in question has inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals. The rise in popularity of smartphones has increased interest in the area of mobile cyber- physical systems. Therefore, various implementations of techniques described herein may be provided via one or more of these technologies.

[00110] A computer program, such as the computer program(s) described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit or part of it suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[00111 ] Method steps may be performed by one or more programmable processors executing a computer program or computer program portions to perform functions by operating on input data and generating output. Method steps also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).

[00112] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer, chip or chipset. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[00113] To provide for interaction with a user, implementations may be implemented on a computer having a display device, e.g., a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, for displaying information to the user and a user interface, such as a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.

[00114] Implementations may be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation, or any combination of such back-end, middleware, or front-end components. Components may be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN) and a wide area network (WAN), e.g., the Internet.

[00115] While certain features of the described implementations have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the various embodiments.

Claims

WHAT IS CLAIMED IS:

1 . A method comprising:

controlling receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device;

determining, by the first wireless device based on the received data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device; and

controlling sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected

retransmission.

2. The method of claim 1 wherein the first wireless device and the second wireless device are one of the following:

the first wireless device is a user device and the second wireless device is a user device;

the first wireless device is a base station and the second wireless device is a base station;

the first wireless device is a user device and the second wireless device is a base station; and

the first wireless device is a base station and the second wireless device is a user device.

3. The method of claim 1 wherein the data indicator comprises a new data indicator that is provided for a hybrid ARQ process, wherein the determining comprises:

determining, by the first wireless device based on the received new data indicator for the hybrid ARQ process, a failure to receive an expected retransmission of a data unit from the second wireless device.

4. The method of claim 1 wherein the determining comprises:

determining, by the first wireless device, a failure to decode a first transmission of the data unit from the second wireless device for a hybrid ARQ process; controlling sending, by the first wireless device, a negative acknowledgement to the second wireless device based on the failure to decode the first transmission of the data unit; and

determining, by the first wireless device, a failure to receive an expected retransmission of the data unit from the second wireless device for the hybrid ARQ process based on the data indicator for the hybrid ARQ process that indicates a transmission of data from the second wireless device that was not previously transmitted from the second wireless device.

5. The method of any of claims 1 through 3 and further comprising :

controlling receiving a poll by the first wireless device from the second wireless device; and

controlling sending, by the first wireless device in response to receiving the poll, a status report to the second wireless device, the status report indicating a status of acknowledgement or negative acknowledgement for one or more data units including a status of negative acknowledgement of the data unit for which a failure to receive an expected retransmission was determined.

6. The method of claim 1 , wherein the data indicator is provided for a hybrid ARQ process, and wherein the controlling sending a signal comprises controlling sending, by the first wireless device to the second wireless device based on the determining, a retransmission failure indication for the hybrid ARQ process indicating a failure to receive an expected retransmission of a data unit from the second wireless device for the hybrid ARQ process.

7. The method of claim 5 wherein the data indicator comprises a new data indicator that is provided for a hybrid ARQ process, and wherein the

retransmission failure indication is sent via a resource associated with the first wireless device and at a time that identifies the hybrid ARQ process.

8. The method of any of claims 1 through 3 wherein the controlling sending signal comprises:

obtaining, by the first wireless device from the second wireless device, uplink resources;

controlling sending, by the first wireless device, a status report to the second wireless device via the obtained uplink resources, the status report indicating a status of acknowledgement or negative acknowledgement for one or more data units including a status of negative acknowledgement of the data unit for which a failure to receive an expected retransmission was determined.

9. The method of claim 1 wherein the data indicator comprises a new data indicator that is provided for a hybrid ARQ process, and further wherein the controlling sending a signal comprises:

a media access control (MAC) entity of the first wireless device notifying a radio link control (RLC) entity of the first wireless device of the determined failure to receive an expected retransmission of the data unit for the hybrid ARQ process; mapping, by the first wireless device, the data unit of the hybrid ARQ process for which a failure to receive an expected retransmission was determined to one or more associated RLC data units; and

obtaining, by the first wireless device from the second wireless device, uplink resources; and

controlling sending a RLC status report from the first wireless device to the second wireless device via the obtained uplink resources, the status report indicating a status of acknowledgement or negative acknowledgement for one or more data units including a status of negative acknowledgement of the one or more associated RLC data units.

10. The method of any of claims 1 through 9 and further comprising applying a restriction for transmission of data units between the first wireless device and the second wireless device wherein radio link control (RLC) data units may be segmented or concatenated for transmission in a physical data unit, but RLC data units may not be both segmented and concatenated for transmission in a physical data unit.

1 1 . An apparatus comprising means for carrying out the method according to any one of claims 1 through 10.

12. A computer program product for a computer, comprising software code portions for performing the steps of any of claims 1 through 10 when said product is run on the computer.

13. An apparatus comprising at least one processor and at least one memory including computer instructions, when executed by the at least one processor, cause the apparatus to:

control receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device;

determine, by the first wireless device based on the received data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device; and

control sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission.

14. A computer program product, the computer program product comprising a computer-readable storage medium and storing executable code that, when executed by at least one data processing apparatus, is configured to cause the at least one data processing apparatus to perform a method comprising:

determining, by the first wireless device based on the received status of the new data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device; and

retransmission.

15. An apparatus comprising:

means for controlling receiving, by a first wireless device from a second wireless device in a wireless network, a data indicator indicating a transmission of data from the second wireless device that was not previously transmitted from the second wireless device;

means for determining, by the first wireless device based on the received data indicator, a failure to receive an expected retransmission of a data unit from the second wireless device; and means for controlling sending, by the first wireless device, a signal to the second wireless device based on the determining the failure to receive the expected retransmission.

16. A method comprising:

determining, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device;

providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data; and

initiating, by the second protocol entity of the first wireless device, a

communication process with the second wireless device to receive the previously transmitted data from the second wireless device.

17. The method of claim 16 wherein the control signal comprises a new data indicator for a hybrid ARQ process, the new data indicator received via a control channel and indicating whether a data transmission received by the first wireless device from the second wireless device via a data channel is a transmission of new data or a retransmission of previously transmitted data.

18. The method of claim 16 wherein the first wireless device and the second wireless device are one of the following:

19. The method of claim 16 wherein the first protocol entity comprises a media access control entity, and the second protocol entity comprises a radio link control entity.

20. The method of claim 16 wherein the control signal comprises a new data indicator for a hybrid ARQ process, wherein the providing a notification comprises: providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data unit, wherein the notification includes information identifying the hybrid ARQ process.

21 . The method of claim 16 wherein the control signal comprises a new data indicator for a hybrid ARQ process, and wherein the initiating, by the second protocol data unit of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data unit from the second wireless device comprises one or more of the following :

controlling sending, from the first wireless device to the second wireless device, information identifying a sequence number last received by the first wireless device;

controlling sending, from the first wireless device to the second wireless device, a retransmission failure indication, the retransmission failure indication identifying either the hybrid ARQ process or a sequence number;

controlling sending, from the first wireless device to the second wireless device, an out-of-order indication to indicate that the first wireless device has received an out-of-order data unit; and

controlling sending, from the first wireless device to the second wireless device, a radio link control status report with a negative acknowledgement indicated for the previously transmitted data.

22. The method of claim 16 wherein the initiating is performed by the second protocol entity to receive the data unit only for up to a maximum number of the notifications received from the first protocol data unit indicating a failure to receive the expected retransmission of the previously transmitted data unit.

23. The method of claim 16 and further comprising: passing out-of-order data from the second protocol entity of the first wireless device to a third protocol entity of the first wireless device while the first wireless device waits to receive the previously transmitted data from the second wireless device, the third protocol entity being provided at a higher protocol layer than the second protocol entity.

24. An apparatus comprising means for carrying out the method according to any one of claims 16 through 23.

25. A computer program product for a computer, comprising software code portions for performing the steps of any of claims 16 through 23 when said product is run on the computer.

26. An apparatus comprising at least one processor and at least one memory including computer instructions, when executed by the at least one processor, cause the apparatus to:

determine, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device;

provide a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data; and

initiate, by the second protocol entity of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data.

27. A computer program product, the computer program product comprising a computer-readable storage medium and storing executable code that, when executed by at least one data processing apparatus, is configured to cause the at least one data processing apparatus to perform a method comprising:

providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data; and initiating, by the second protocol entity of the first wireless device, a

communication process with the second wireless device to receive the previously transmitted data.

28. An apparatus comprising:

means for determining, by a first protocol entity of a first wireless device in a wireless network based on a control signal received from a second wireless device, a failure to receive an expected retransmission of previously transmitted data from the second wireless device;

means for providing a notification, by the first protocol entity of the first wireless device to a second protocol entity of the first wireless device, of the failure to receive the expected retransmission of the previously transmitted data; and means for initiating, by the second protocol entity of the first wireless device, a communication process with the second wireless device to receive the previously transmitted data.