Patent Description:
<CIT> relates to a mechanism for providing feedback in sidelink transmissions without involving a centralized controller, such as a base station (e.g., an eNB). <CIT> relates to communication network protocols, including vehicle-to-device, vehicle-to-vehicle, and vehicle-to-network communication resource allocation and feedback methods. 3GPP TSG RAN WG1 #<NUM>, R1-<NUM>, "Physical layer procedure for NR V2X" relates to issues of physical layer procedure. <CIT> relates to methods and devices are provided for allocating radio resources in a unicast sidelink communication with feedback transmissions. <CIT> relates to a technique for user equipment UE that receives a D2D signal to transmit a feedback signal in the D2D communication.

In <NUM>rd generation partnership project ("3GPP") specifications, device-to-device ("D2D") communications are referred to as sidelink communications or communications over a PC5 interface. <FIG> is a schematic diagram illustrating a communication network <NUM> that includes network nodes <NUM> and communication devices <NUM> connected to the network nodes <NUM> and/or to each other via one or more sidelink communication channels. Sidelink communications allow devices or user equipments ("UEs") (also referred to as communication devices) to establish communication when out of network coverage ("OOC"). Sidelink communications can be used in partial coverage situations (e.g., when one of the UEs is in coverage but the other is OOC) or in coverage ("InC") situations. When operated InC or in partial coverage, the network may or may not control partially or totally the behavior of the UEs that communicate through the sidelink.

Operation without network control presents multiple design challenges. For example, UEs may need to select resources for transmission in an autonomous way instead of receiving a grant from a base station (e.g., a gNB). This can result in multiple UEs selecting the same resources, which can cause colliding transmissions. Even if the system operates without collisions, it is can be desirable that multiple users (usually physically separated) use the same radio resources.

In response to receiving and decoding a data transmission, a receiving UE can transmit a feedback message using a physical sidelink feedback channel ("PSFCH"). The PSFCH is a transmission spanning a few symbols (e.g., <NUM>-<NUM> symbols) and <NUM> subcarriers (e.g., on a resource block ("RB")). Conventional techniques for providing feedback messages may result in multiple receivers selecting the same PSFCH resource (e.g., the same RB and the same sequence). If different receivers select the same PSFCH resource, they may confuse the corresponding transmitters.

The invention provides a method of operating a first communication device according to independent claim <NUM>, a method of operating a second communication device according to independent claim <NUM>, a first communication device according to independent claim <NUM>, a second communication device according to independent claim <NUM>, and computer programs according to independent claims <NUM> and <NUM>. Preferred embodiments are defined by the subject-matter of dependent claims.

Various embodiments described herein ensure that different physical sidelink feedback channel ("PSFCH") resources are selected for acknowledging the reception (positive or negative) of physical sidelink shared channel ("PSSCH") transmissions that are scheduled by physical sidelink control channels ("PSCCHs") that use different demodulation reference signals ("DM-RS") or by PSSCHs that include different fields.

Several layers in the protocol stack include sidelink-related functionality including the physical ("PHY") layer. At the PHY layer, multiple PHY channels are defined including the physical sidelink control channel ("PSCCH") and the physical sidelink shared channel ("PSSCH").

The PSCCH can carry the sidelink control information ("SCI") that can be necessary for enabling sidelink communications. The SCI includes information that can be used for successfully decoding other sidelink transmissions such as PSSCH transmissions. For example, the SCI may identify the modulation and coding scheme used for encoding the PSSCH, the time-frequency resource allocation in which the PSSCH is transmitted, and/or the multi-antenna configuration used for transmitting the PSSCH.

The PSCCH can be transmitted using a predefined format in predefined time-frequency resources. Therefore, a UE can blindly attempt to decode PSCCH using the predefined format in the predefined resources. If the UE succeeds, then the UE can proceed to decode the corresponding PSSCH using the format described by the SCI. The PSSCH can carry a higher-layer payload (e.g., data from an application).

Wireless signals transmitted by a UE (also referred to as a transmitting ("TX") UE) are transformed by the wireless channel before they arrive at another UE (also referred to herein as a receiving ("RX") UE. The transformation may include attenuation, distortion, and/or phase shifts, and the transformation may vary over time. The RX UE may need to know, at least to some extent, the transformation applied by the wireless channel in order to be able to retrieve the message sent by the TX UE. To allow the RX UE to estimate the wireless channel, the TX UE can insert some predefined signals, knows as reference signals ("RS"). Once the RX UE has estimated the channel it proceeds to decode the message sent by the TX UE. The more accurate the channel estimates, the higher the chances that the message will be decoded correctly.

Like most PHY channels, PSCCH has associated demodulation RS ("DM-RS" or "DMRS"), commonly referred to as PSCCH DMRS.

As described before, PSCCH is transmitted with a predefined format, which allows for efficient blind decoding of the transmissions. In some examples, the DMRS sequence for PSCCH is also predefined. However, if the same PSCCH DMRS sequence is used by multiple TX UEs on the same radio resources (due to a collision or to spatial resource reutilization), the quality of the channel estimates can be severely degraded.

Zadoff-Chu ("ZC") sequences are a special group of sequences with special properties that make them suitable as reference signals. For example, one of these properties states that a ZC sequence and a cyclically-shifted version of the ZC sequences are orthogonal.

In long term evolution ("LTE") sidelink, the DM-RS sequence transmitted with PSCCH is generated by first generating a predefined ZC sequence and then applying a randomly selected cyclic shift ("CS") to the predefined ZC sequence. This way of generating PSCCH DM-RS reduces the probability that two nearby UEs select the same PSCCH DM-RS sequence.

For new radio ("NR") the details have not been decided yet, but a similar mechanism may be used. That is, a parameter of the DM-RS sequence transmitted with PSCCH can be selected at random. The parameter may be a CS, like in LTE, or a different parameter like a code (e.g., an orthogonal cover code), a sequence used for DM-RS, a value for initializing the sequence generator (e.g., c init), or in general a parameter used for generating the DM-RS.

This way of generating PSCCH DM-RS ensures that if two UEs transmit PSCCH in the same resources, the channel between one (or both) of them and a RX UE can be estimated with accuracy. Once one channel is accurately estimated, the PSCCH can often be decoded despite the interference from the other transmission.

NR sidelink supports the use of hybrid automatic response request ("HARQ") feedback, sent from a receiver to a transmitter to inform the transmitter of whether the receiver could successfully decode the transmission. A TX UE can send a transmission including PSCCH and PSSCH. The RX UE can attempt to decode the control signaling in the transmission (e.g., carried in PSCCH and possibly also in PSSCH). After this, the RX UE can attempt to decode the data payload carried in the PSSCH. In some examples, If the RX UE decodes the control information but fails to decode the data payload, the RX UE sends a negative feedback acknowledgement message to the TX UE. Otherwise, the RX UE does not send any feedback message. In additional or alternative examples, If the RX UE decodes the control information but fails to decode the data payload, the RX sends a negative feedback acknowledgement message to the TX UE. If the RX UE decodes the control information as well as the data payload, it sends a positive feedback acknowledgement message to the transmitter. Otherwise, the receiver UE does not send any feedback message.

In either of the above examples, the feedback message can be transmitted using a physical sidelink feedback channel ("PSFCH"). The PSFCH is a transmission spanning a few symbols (e.g., <NUM>-<NUM> symbols) and <NUM> subcarriers (e.g., on a resource block ("RB")). The transmission of the PSFCH can depend on a few parameters besides the feedback message itself. For example, the PSFCH can depend on the RB used for transmission (e.g.. , which RB within the entire system bandwidth) and/or the sequence used for transmission (which in turn can depend on the base sequence and/or the cyclic shift).

Conventional techniques for providing feedback messages may result in multiple receivers selecting the same PSFCH resource (e.g., the same RB and the same sequence). If different receivers select the same PSFCH resource, they may confuse the corresponding transmitters.

In one example, a first UE sends a message to a second UE, which fails to decode the PSCCH and PSSCH. A third UE sends a message to a fourth UE, which decodes both PSCCH and PSSCH. The PSFCH resource to be used by the second UE and the fourth UE is the same. The fourth UE sends a positive feedback acknowledgment message that is received by both the first UE and the second UE. As a result, the first UE can incorrectly believe the second UE has correctly decode its message.

In various embodiments of the present disclosure, a feedback channel resource selection mechanism or function ensures or at least improves the likelihood that different feedback channel resources are selected by respective communication devices for providing feedback transmissions (e.g., positive acknowledgment ("ACK")/ negative acknowledgment ("NACK")) in response to sidelink data channel transmissions.

<FIG> is a signal flow diagram illustrating an example of operations performed by a communication device 120a and a communication device 120b during a feedback process. At operation <NUM>, communication device 120b (e.g., a TX UE) transmits control information to communication device 120a (e.g., a RX UE) via a control channel. At operation <NUM>, communication device 120b transmits data to communication device 120a via a data channel. At operation <NUM>, communication device 120a attempts to decode the data transmission. At operation <NUM>, communication device 120a determines a parameter of the control channel. At operation <NUM>, communication device 120a selects a transmission resource based on the parameter. At operation <NUM>, communication device 120a transmits a feedback message, response to the data transmission, to the communication device 120b using the transmission resource.

<FIG> is a block diagram illustrating elements of a wireless device <NUM> (also referred to as a mobile terminal, a mobile communication terminal, a wireless communication device, a wireless terminal, mobile device, a wireless communication terminal, a user equipment ("UE"), a user equipment node/terminal/device, etc.) configured to provide wireless communication according to embodiments of inventive concepts. (Wireless device <NUM> may be provided, for example, as discussed below with respect to wireless device <NUM> of <FIG>, UE <NUM> of <FIG>, UEs <NUM>, <NUM> of <FIG>, and UE <NUM> of <FIG>. ) As shown, wireless device UE may include an antenna <NUM> (e.g., corresponding to antenna <NUM> of <FIG>), and transceiver circuitry <NUM> (also referred to as a transceiver, e.g., corresponding to interface <NUM> of <FIG>; interfaces <NUM>, <NUM>, <NUM>, transmitter <NUM>, and receiver <NUM> of <FIG>; and radio interface <NUM> of <FIG>) including a transmitter and a receiver configured to provide uplink and downlink radio communications with a base station(s) (e.g., corresponding to network node <NUM> of <FIG>, also referred to as a RAN node) of a radio access network. Wireless device UE may also include processing circuitry <NUM> (also referred to as a processor, e.g., corresponding to processing circuitry <NUM> of <FIG>, processor <NUM> of <FIG>, and processing circuitry <NUM> of <FIG>) coupled to the transceiver circuitry, and memory circuitry <NUM> (also referred to as memory, e.g., corresponding to device readable medium <NUM> of <FIG>) coupled to the processing circuitry. The memory circuitry <NUM> may include computer readable program code that when executed by the processing circuitry <NUM> causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry <NUM> may be defined to include memory so that separate memory circuitry is not required. Wireless device UE may also include an interface (such as a user interface) coupled with processing circuitry <NUM>, and/or wireless device UE may be incorporated in a vehicle.

As discussed herein, operations of wireless device UE may be performed by processing circuitry <NUM> and/or transceiver circuitry <NUM>. For example, processing circuitry <NUM> may control transceiver circuitry <NUM> to transmit communications through transceiver circuitry <NUM> over a radio interface to a radio access network node (also referred to as a base station) and/or to receive communications through transceiver circuitry <NUM> from a RAN node over a radio interface. Moreover, modules may be stored in memory circuitry <NUM>, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry <NUM>, processing circuitry <NUM> performs respective operations (e.g., operations discussed below with respect to Example Embodiments relating to wireless devices).

Within the context of this disclosure, the term communication device is a device which is able to communicate with a network node, such as a base station, or with another wireless device by transmitting and/or receiving wireless signals. Thus, the term communication device encompasses, but is not limited to: a mobile phone, a stationary or mobile wireless device for machine-to-machine communication, an integrated or embedded wireless card, or an externally plugged in wireless card. The communication device includes any device intended for accessing services via an access network and configured to communicate over the access network. For example, the communication device may also include, but is not limited to: a smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic (e.g., television, radio, lighting arrangement, tablet computer, laptop, or PC). The communication device may be a portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data, via a wireless or wireline connection. As used herein, the term communication device may be used interchangeably with UE or user device.

<FIG> is a block diagram illustrating elements of a radio access network RAN node <NUM> (also referred to as a network node, base station, eNodeB/eNB, gNodeB/gNB, etc.) of a Radio Access Network ("RAN") configured to provide cellular communication according to embodiments of inventive concepts. (RAN node <NUM> may be provided, for example, as discussed below with respect to network node <NUM> of <FIG>, base stations 4412a-c of <FIG>, and/or base station <NUM> of <FIG>, all of which should be considered interchangeable in the examples and embodiments described herein and be withing the intended scope of this disclosure, unless otherwise noted) As shown, the RAN node may include transceiver circuitry <NUM> (also referred to as a transceiver, e.g., corresponding to portions of interface <NUM> of <FIG> and/or portions of radio interface <NUM> of <FIG>) including a transmitter and a receiver configured to provide uplink and downlink radio communications with mobile terminals. The RAN node may include network interface circuitry <NUM> (also referred to as a network interface, e.g., corresponding to portions of interface <NUM> of <FIG> and/or portions of communication interface <NUM> of <FIG>) configured to provide communications with other nodes (e.g., with other base stations) of the RAN and/or core network CN. The network node may also include processing circuitry <NUM> (also referred to as a processor, e.g., corresponding to processing circuitry <NUM> of <FIG> and/or processing circuitry <NUM> of <FIG>) coupled to the transceiver circuitry, and memory circuitry <NUM> (also referred to as memory, e.g., corresponding to device readable medium <NUM> of <FIG>) coupled to the processing circuitry. The memory circuitry <NUM> may include computer readable program code that when executed by the processing circuitry <NUM> causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry <NUM> may be defined to include memory so that a separate memory circuitry is not required.

As discussed herein, operations of the RAN node may be performed by processing circuitry <NUM>, network interface <NUM>, and/or transceiver <NUM>. For example, processing circuitry <NUM> may control transceiver <NUM> to transmit downlink communications through transceiver <NUM> over a radio interface to one or more mobile terminals or mobile UEs and/or to receive uplink communications through transceiver <NUM> from one or more mobile terminals or mobile UEs over a radio interface. Similarly, processing circuitry <NUM> may control network interface <NUM> to transmit communications through network interface <NUM> to one or more other network nodes and/or to receive communications through network interface from one or more other network nodes. Moreover, modules may be stored in memory <NUM>, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry <NUM>, processing circuitry <NUM> performs respective operations (e.g., operations discussed below with respect to Example Embodiments relating to RAN nodes).

As used herein, network node refers to equipment capable, configured, arranged, and/or operable to communicate directly or indirectly with a communication device and/or with other network nodes or equipment in the radio communication network to enable and/or provide wireless access to the user device and/or to perform other functions (e.g., administration) in the radio communication network. Examples of network nodes include, but are not limited to, base stations ("BSs") (e.g., radio base stations, Node Bs, evolved Node Bs ("eNBs"), gNode Bs, access points ("APs") (e.g., radio access points). A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and/or remote radio units ("RRUs"), sometimes referred to as Remote Radio Heads ("RRHs"). Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system ("DAS"). Yet further examples of network nodes include multi-standard radio ("MSR") equipment such as MSR BSs, network controllers such as radio network controllers ("RNCs") or base station controllers ("BSCs"), base transceiver stations ("BTSs"), transmission points, transmission nodes, multi-cell/multicast coordination entities ("MCEs"), core network nodes (e.g., mobile switching centers ("MSCs"), mobility management entities ("MMEs")), operation and management ("O&M") nodes, operations support system nodes, self-organizing network ("SON") nodes, positioning nodes (e.g., enhanced serving mobile location centers ("E-SMLCs"), and/or MDTs. As another example, a network node may be a virtual network node. More generally, however, network nodes may represent any suitable device (or group of devices) capable, configured, arranged, and/or operable to enable and/or provide a user device with access to the telecommunications network or to provide some service to a user device that has accessed the telecommunications network.

According to some other embodiments, a network node may be implemented as a core network CN node without a transceiver. In such embodiments, transmission to a wireless device UE may be initiated by the network node so that transmission to the wireless device is provided through a network node including a transceiver (e.g., through a base station or RAN node). According to embodiments where the network node is a RAN node including a transceiver, initiating transmission may include transmitting through the transceiver.

<FIG> is a block diagram illustrating elements of a core network CN node (e.g., an SMF node, an AMF node, etc.) of a communication network configured to provide cellular communication according to embodiments of inventive concepts. As shown, the CN node may include network interface circuitry <NUM> (also referred to as a network interface) configured to provide communications with other nodes of the core network and/or the radio access network RAN. The CN node may also include a processing circuitry <NUM> (also referred to as a processor) coupled to the network interface circuitry, and memory circuitry <NUM> (also referred to as memory) coupled to the processing circuitry. The memory circuitry <NUM> may include computer readable program code that when executed by the processing circuitry <NUM> causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry <NUM> may be defined to include memory so that a separate memory circuitry is not required.

As discussed herein, operations of the CN node may be performed by processing circuitry <NUM> and/or network interface circuitry <NUM>. For example, processing circuitry <NUM> may control network interface circuitry <NUM> to transmit communications through network interface circuitry <NUM> to one or more other network nodes and/or to receive communications through network interface circuitry from one or more other network nodes. Moreover, modules may be stored in memory <NUM>, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry <NUM>, processing circuitry <NUM> performs respective operations (e.g., operations discussed below with respect to Example Embodiments relating to core network nodes).

A UE can be connected to a single base station in order to use the mobile network services (e.g., making phone calls, messaging, and communicating data). When a UE does not have any data to send its connection can be idle and be torn down by the UE.

In some embodiments, one or more resources for transmitting a feedback transmission in a feedback channel are selected by a communication device in dependence on or as a function of one or more of: <NUM>) a parameter of a reference signal transmitted with a control channel that schedules a data channel transmission to which the feedback transmission corresponds; <NUM>) a field of the control channel that schedules the data channel transmission; and/or <NUM>) a function of the fields of the control channel that schedules the data channel transmission.

In additional or alternative embodiments, the communication device is mounted on, part of, or carried in a vehicle. In additional or alternative embodiments, the communication device may be a communication device configured for use by a public safety responder. In additional or alternative embodiments, the data channel transmission is a vehicle-to-vehicle ("V2V") communication, a public safety ("PS") communication, or a proximity service ("ProSe") communication. In additional or alternative embodiments, the feedback message is one of a positive or negative acknowledgement (e.g., an ACK or a NACK message, respectively). In additional or alternative embodiments, the feedback message is a negative acknowledgement (e.g., a NACK message) and no feedback message is sent if the data channel is decoded correctly. In additional or alternative embodiments, the feedback channel is a physical sidelink feedback channel ("PSFCH"), the control channel is a physical sidelink control channel ("PSCCH"), and the data channel is a physical sidelink shared channel ("PSSCH").

According to the claimed invention, the feedback channel resource is selected at least partially based on a parameter of a reference signal transmitted with the control channel that schedules the data channel transmission for which the feedback transmission is made. A first communication device receives a transmission from a second communication device. This transmission includes or is communicated using a control channel (e.g., PSCCH) and a data channel (e.g., PSSCH), wherein the control channel (or data channel) includes a corresponding reference signal, such as a DM-RS. The first communication device detects the transmission from the second communication device and attempts to decode it. Based on the outcome of the decoding operation, the first communication device sends a feedback message to the second communication device. For example, the first communication device sends ACK if it can decode the data channel and NACK if it cannot. The feedback channel resource used for conveying the feedback message is selected based on one or more of the reference signals of the control channel (or data channel) or a parameter associated with or from the reference signals.

According to the claimed invention, the feedback resource is selected based on one or more of the following parameters of the reference signals: the cyclic shift of the reference signals; the base sequence of the reference signals; the value used for initializing the generator of the sequence used as reference signal; the code of the reference signal (e.g., an orthogonal cover code); and a parameter of the reference signals that is randomly selected by the communication device that transmitted the data channel that is being acknowledged.

In some embodiments, the feedback channel resource is selected at least partially based on one or more fields of the control channel (e.g., PSCCH) that schedules the data channel (e.g., PSSCH) transmission. In some examples, a first communication device receives a transmission from a second communication device. This transmission includes or is communicated using a control channel (e.g., PSCCH) and a data channel (PSSCH), wherein the control channel (or data channel) includes a corresponding reference signal, such as a DM-RS. The first communication device detects the transmission from the second communication device and attempts to decode it. Based on the outcome of the decoding operation, the first communication device sends a feedback message to the second communication device. For example, the first communication device sends ACK if it can decode the data channel and NACK if it cannot. The feedback channel resource used for conveying the feedback message is selected based on a function of one or more of the fields of the control channel that scheduled the data channel transmission.

In additional or alternative embodiments, the feedback resource may be selected as a function of a CRC of the fields of the control channel. For example, the CRC of the sidelink control information carried by the control channel may be used.

In some embodiments, the feedback channel resource is selected at least partially based on a field of the control channel that schedules the data channel transmission. In some examples, a first communication device receives a transmission from a second communication device. This transmission includes or is communicated using a control channel (e.g., PSCCH) and a data channel (PSSCH), wherein the control channel (or data channel) includes a corresponding reference signal, such as a DM-RS. The first communication device detects the transmission from the second communication device and attempts to decode it. Based on the outcome of the decoding operation, the first communication device sends a feedback message to the second communication device. For example, the first communication device sends ACK if it can decode the data channel and NACK if it cannot. The feedback channel resource used for conveying the feedback message is selected based on one or more of the fields of the control channel that scheduled the data channel transmission.

In additional or alternative embodiments, the feedback resource may be selected based on one or more of the following fields of the sidelink control information, which is carried by the control channel: an identifier ("ID") of the transmitter UE of the PSCCH; an identifier of the intended receiver UE of the PSCCH; a destination group ID; and a service ID.

Various embodiments described herein may provide potential advantages. One potential advantage may provide effective selection of feedback channel resources by communication devices configured for sidelink communications. Additional potential advantages of various embodiments may include: <NUM>) improving resource utilization in sidelink channels; <NUM>) reducing signaling overhead; and <NUM>) increasing network capacity for sidelink communications.

Operations of a first communication device (implemented using the structure of the block diagram of <FIG> will now be discussed with reference to the flow chart of <FIG> according to some embodiments of inventive concepts. For example, modules may be stored in memory <NUM> of <FIG>, and these modules may provide instructions so that when the instructions of a module are executed by respective wireless device processing circuitry <NUM>, processing circuitry <NUM> performs respective operations of the flow chart.

At block <NUM>, processing circuitry <NUM> receives, via transceiver <NUM>, control information from a second communication device over a control channel. Receiving the control information includes receiving a reference signal with the control channel. In additional or alternative embodiments, the reference signal includes a demodulation reference signal ("DM-RS") that schedules the data channel transmission. In additional or alternative embodiments, the control channel is a physical sidelink control channel ("PSCCH"). In additional or alternative embodiments, receiving the data channel transmission includes receiving the data channel transmission from the second communication device via a physical sidelink shared channel ("PSSCH").

At block <NUM>, processing circuitry <NUM> receives, via transceiver <NUM>, a data channel transmission from the second communication device using the control information. In some embodiments, receiving the data channel transmission from the second communication device using the control information includes receiving the data channel transmission directly from the second communication device through a sidelink communication protocol without directing the data channel transmission through any network nodes in the communications network.

At block <NUM>, processing circuitry <NUM> determines a feedback message to transmit to the second communication device based on an attempt to decode the data channel transmission.

At block <NUM>, processing circuitry <NUM> determines a parameter of the control channel. According to the claimed invention, determining the parameter includes determining one of: a cyclic shift, a base sequence, a sequence generator initialization value, and a code associated with one or more reference signals included in the control information and determining the parameter includes randomly selecting a parameter of the reference signal. In additional or alternative embodiments, determining the parameter includes determining the parameter based on one or more of fields of the control channel. In additional or alternative embodiments, the one or more fields includes a cyclic redundancy check ("CRC") value associated with the control channel. In additional or alternative embodiments, the one or more fields includes at least one of: an identifier of the second communication device; an identifier of the first communication device; a destination group identifier; and a service identifier.

At block <NUM>, processing circuitry <NUM> selects a resource to use for transmitting the feedback message to the second communication device based on the parameter. In some embodiments, selecting the resource includes selecting the resource based directly on the parameter. In additional or alternative embodiments, selecting the resource includes selecting the resource based on a function of the parameter.

In additional or alternative embodiments, selecting the resource to use for sending the feedback message to the second communication device based on the parameter includes selecting the resource based on a function of a CRC value of the control channel.

At block <NUM>, processing circuitry <NUM> transmits, via transceiver <NUM>, the feedback message to the second communication device using the resource.

Various operations from the flow chart of <FIG> may be optional with respect to some embodiments of communication devices and related methods.

Operations of a second communication device (implemented using the structure of the block diagram of <FIG> will now be discussed with reference to the flow chart of <FIG> according to some embodiments of inventive concepts. For example, modules may be stored in memory <NUM> of <FIG>, and these modules may provide instructions so that when the instructions of a module are executed by respective wireless device processing circuitry <NUM>, processing circuitry <NUM> performs respective operations of the flow chart.

At block <NUM>, processing circuitry <NUM> determines a parameter of a control channel. According to the claimed invention, determining the parameter includes determining one of: a cyclic shift, a base sequence, a sequence generator initialization value, and a code associated with one or more reference signals included in the control information and determining the parameter includes randomly selecting a parameter of the reference signal. In additional or alternative embodiments, determining the parameter includes determining the parameter based on one or more of fields of the control channel. In additional or alternative embodiments, the one or more fields includes a cyclic redundancy check ("CRC") value associated with the control channel. In additional or alternative embodiments, the one or more fields includes at least one of: an identifier of the second communication device; an identifier of the first communication device; a destination group identifier; and a service identifier.

At block <NUM>, processing circuitry <NUM> transmits, via transceiver <NUM>, control information to a first communication device over the control channel. The control information can include scheduling of a data channel transmission (e.g., the data channel transmission in block <NUM>). In some embodiments, transmitting the control information includes transmitting a reference signal with the control channel. In additional or alternative embodiments, the reference signal includes a demodulation reference signal ("DM-RS"). In additional or alternative embodiments, the control channel is a physical sidelink control channel ("PSCCH"). In additional or alternative embodiments, transmitting the data channel transmission includes transmitting the data channel transmission from the second communication device via a physical sidelink shared channel ("PSSCH").

At block <NUM>, processing circuitry <NUM> transmits, via transceiver <NUM>, a data channel transmission to the first communication device. In some embodiments, transmitting the data channel transmission to the first communication device is based on the schedule in the control information and includes transmitting the data channel transmission directly to the first communication device through a sidelink communication protocol without directing the data channel transmission through any network nodes in the communications network.

At block <NUM>, processing circuitry <NUM> determines a resource for receiving a feedback message from the first communication device. In some embodiments, determining the resource includes determining the resource based directly on the parameter. In additional or alternative embodiments, determining the resource includes determining the resource based on a function of the parameter.

In additional or alternative embodiments, determining the resource for receiving the feedback message from the first communication device based on the parameter includes determining the resource based on a function of a CRC value of the control channel.

At block <NUM>, processing circuitry <NUM> receives, via transceiver <NUM>, the feedback message from the first communication device.

Explanations are provided below for various abbreviations/acronyms used in the present disclosure.

Additional explanation is provided below.

<FIG> illustrates a wireless network in accordance with some embodiments.

Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in relation to a wireless network, such as the example wireless network illustrated in <FIG>. For simplicity, the wireless network of <FIG> only depicts network <NUM>, network nodes <NUM> and 4160b, and WDs <NUM>, 4110b, and 4110c (also referred to as mobile terminals). In practice, a wireless network may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or end device. Of the illustrated components, network node <NUM> and wireless device (WD) <NUM> are depicted with additional detail. The wireless network may provide communication and other types of services to one or more wireless devices to facilitate the wireless devices' access to and/or use of the services provided by, or via, the wireless network.

As used herein, wireless device (WD) refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term WD may be used interchangeably herein with user equipment (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. In some embodiments, a WD may be configured to transmit and/or receive information without direct human interaction. For instance, a WD may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network. Examples of a WD include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over IP (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless cameras, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a smart device, a wireless customer-premise equipment (CPE). a vehicle-mounted wireless terminal device, etc. A WD may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may in this case be referred to as a D2D communication device. As yet another specific example, in an Internet of Things (IoT) scenario, a WD may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another WD and/or a network node. The WD may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the WD may be a UE implementing the 3GPP narrow band internet of things (NB-loT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances (e.g. refrigerators, televisions, etc.) personal wearables (e.g., watches, fitness trackers, etc.). In other scenarios, a WD may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A WD as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a WD as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal.

<FIG> illustrates a user Equipment in accordance with some embodiments.

UE <NUM> may be any UE identified by the 3rd Generation Partnership Project (3GPP), including a NB-loT UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE. UE <NUM>, as illustrated in <FIG>, is one example of a WD configured for communication in accordance with one or more communication standards promulgated by the 3rd Generation Partnership Project (3GPP), such as 3GPP's GSM, UMTS, LTE, and/or <NUM> standards.

Network connection interface <NUM> may be configured to provide a communication interface to network 4243a. Network 4243a may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 4243a may comprise a Wi-Fi network.

In <FIG>, processing circuitry <NUM> may be configured to communicate with network 4243b using communication subsystem <NUM>. Network 4243a and network 4243b may be the same network or networks or different network or networks. Communication subsystem <NUM> may be configured to include one or more transceivers used to communicate with network 4243b.

Network 4243b may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 4243b may be a cellular network, a Wi-Fi network, and/or a near-field network.

<FIG> illustrates a virtualization environment in accordance with some embodiments.

Virtual machines <NUM> comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer <NUM> or hypervisor.

<FIG> illustrates a telecommunication network connected via an intermediate network to a host computer in accordance with some embodiments.

Access network <NUM> comprises a plurality of base stations 4412a, 4412b, 4412c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 4413a, 4413b, 4413c. Each base station 4412a, 4412b, 4412c is connectable to core network <NUM> over a wired or wireless connection <NUM>. A first UE <NUM> located in coverage area 4413c is configured to wirelessly connect to, or be paged by, the corresponding base station 4412c. A second UE <NUM> in coverage area 4413a is wirelessly connectable to the corresponding base station 4412a.

<FIG> illustrates a host computer communicating via a base station with a user equipment over a partially wireless connection in accordance with some embodiments.

It is noted that host computer <NUM>, base station <NUM> and UE <NUM> illustrated in <FIG> may be similar or identical to host computer <NUM>, one of base stations 4412a, 4412b, 4412c and one of UEs <NUM>, <NUM> of <FIG>, respectively.

Wireless connection <NUM> between UE <NUM> and base station <NUM> is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments may improve the performance of OTT services provided to UE <NUM> using OTT connection <NUM>, in which wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may improve the random access speed and/or reduce random access failure rates and thereby provide benefits such as faster and/or more reliable random access.

<FIG> illustrates methods implemented in a communication system including a host computer, a base station and a user equipment in accordance with some embodiments.

The communication system includes a host computer, a base station and a UE which may be those described with reference to <FIG>.

<FIG> illustrates methods implemented in a communication system including a host computer, a base station and a user equipment in accordance with some embodiments.

The communication system includes a host computer, a base station and a UE which may be those described with reference to <FIG>.

The communication system includes a host computer, a base station and a UE which may be those described with reference to <FIG>.

The communication system includes a host computer, a base station and a UE which may be those described with reference to <FIG>.

The term "and/or" (abbreviated "/") includes any and all combinations of one or more of the associated listed items.

Claim 1:
A method of operating a first communication device in a communications network, the method comprising:
receiving (<NUM>) control information from a second communication device over a control channel, wherein receiving the control information comprises receiving a reference signal with the control channel;
receiving (<NUM>) a data channel transmission from the second communication device using the control information;
determining (<NUM>) a feedback message to transmit to the second communication device based on an attempt to decode the data channel transmission;
determining (<NUM>) a parameter of the control channel by determining a parameter of the reference signal comprising one of:
a cyclic shift, a base sequence, a sequence generator initialization value, a code associated with the reference signal, the parameter of the reference signal having been randomly selected by the second communication device;
selecting (<NUM>) a resource to use for transmitting the feedback message to the second communication device based on the parameter of the control channel; and
transmitting (<NUM>) the feedback message to the second communication device using the resource.