Method and apparatus for HARQ feedback for variable code rate retransmissions - Patents.com

Abstract

A method and apparatus for providing feedback in a HARQ scheme is described. A transmission-specific channel quality indicator (CQI) feedback scheme is described. A channel coding related feedback scheme is also described.

Description

[Technical field]

[0001] The present disclosure relates to a method and apparatus for wireless communication based on a HARQ feedback scheme. [Background technology]

[0002] Hybrid Automatic Repeat Request (HARQ) is a common technique used in wireless communications to improve the chances of successfully transmitting and receiving a message. The message is coded with an error-correcting scheme so that some errors introduced by the wireless channel can be corrected at the receiver without further action from the transmitter. If the receiver cannot decode the message, it sends HARQ feedback to the transmitter, causing the transmitter to retransmit the message.

[0003] Improvements to commonly used HARQ schemes have been developed. For example, a cross-code block coding based approach may be used to generate the retransmitted messages. In an example implementation, the retransmissions are messages generated from at least a portion of multiple different code blocks (CBs), which may result in, for example, more efficient use of network resources. Retransmission schemes that utilize cross-code block coding techniques may be referred to as cross-CB HARQ schemes, or two-dimensional (2D) HARQ schemes.

[0004] Further improvements to HARQ retransmissions are generally desirable, e.g., solutions that help improve the nature or content of retransmissions and / or that help reduce the amount of resources used for retransmissions are generally desirable. Summary of the Invention [Means for solving the problem]

[0005] In various examples, this disclosure describes methods and apparatus for wireless communication using a retransmission scheme. In particular, a feedback scheme is described that enables a transmitter node to determine the amount of redundancy to be used for a retransmission.

[0006] In some examples, the feedback scheme may be based on an instantaneous channel quality indicator (CQI), which is measured based on an initial transmission.

[0007] Furthermore, a new feedback-based cross-CB coding transmission scheme is also described. In addition, the new feedback scheme is extended to multicast and network coding scenarios.

[0008] In an example aspect, the present disclosure describes a method in a receiver node, the method including receiving a data transmission from a transmitter node, the data transmission including transmission of an associated reference signal, determining a transmission-specific channel quality indicator (CQI) associated with the received data transmission from the reference signal, and transmitting feedback indicative of the transmission-specific CQI to the transmitter node.

[0009] In one example of the aforementioned exemplary embodiment of the method, the reference signal may be a demodulation reference signal (DMRS).

[0010] In one example of any of the aforementioned exemplary aspects of the method, the data transmission may include one or more code blocks, and the method may further include performing a decoding operation to decode the one or more code blocks. The method may further include, in response to successful decoding of the one or more code blocks, the feedback indicative of the transmission-specific CQI represents a positive acknowledgement (ACK) indicating successful decoding, or in response to unsuccessful decoding of at least one of the one or more code blocks, the feedback indicative of the transmission-specific CQI represents a negative acknowledgement (NACK) indicating unsuccessful decoding.

[0011] In one example of any of the aforementioned exemplary aspects of the method, the feedback indicative of the transmission-specific CQI may be transmitted separately from the response feedback.

[0012] In one example of any of the aforementioned exemplary aspects of the method, the transmit-specific CQI may indicate the highest supported modulation and coding scheme (MCS) that can be supported by the current channel quality measured from the reference signal and that provides a block error rate (BLER) below a defined threshold.

[0013] In one example of the aforementioned exemplary aspect of the method, the transmit-specific CQI may be determined by identifying a CQI index value from a defined CQI table that corresponds to the highest supported MCS, and the identified CQI index value is used as the transmit-specific CQI.

[0014] In one example of the aforementioned exemplary embodiment of the method, a reserved CQI index value in a defined CQI table may be defined to indicate an ACK.

[0015] In one example of any of the aforementioned exemplary aspects of the method, determining the transmission-specific CQI may further include determining a differential CQI representative of a difference in channel quality between a current channel quality measured from a reference signal of the received data transmission and a previously reported channel quality, where the differential CQI is used as the transmission-specific CQI.

[0016] In one example of the aforementioned exemplary aspect of the method, the differential CQI may be indicated as the difference between a first MCS used for the received data transmission based on the previously reported channel quality and a second MCS that is the highest supported MCS that can be supported by the current channel quality.

[0017] In one example of any of the aforementioned exemplary aspects of the method, the data transmission may be a retransmission that includes one or more retransmitted code blocks or one or more cross block check blocks generated from selected bits across one or more code blocks of the data transmission.

[0018] In one example of any of the aforementioned exemplary aspects of the method, the method may further include, after transmitting the feedback to the transmitter node, receiving a retransmission from the transmitter node, the retransmission using at least one retransmission parameter that differs from a corresponding parameter used for the data transmission.

[0019] In another example aspect, the present disclosure describes a method in a transmitter node, the method including: transmitting a data transmission to a receiver node, the data transmission including a transmission of one or more code blocks and an associated reference signal; receiving feedback from the receiver node indicative of a transmission-specific channel quality indicator (CQI) associated with the received data transmission; and transmitting a retransmission to the receiver node using retransmission parameters determined based on the received feedback.

[0020] In one example of the aforementioned exemplary embodiment of the method, the reference signal may be a demodulation reference signal (DMRS).

[0021] In one example of any of the aforementioned exemplary aspects of the method, the feedback indicative of the transmit-specific CQI may represent a negative acknowledgement (NACK) indicating unsuccessful decoding of one or more code blocks at the receiver node.

[0022] In one example of any of the aforementioned exemplary aspects of the method, the feedback indicative of the transmission-specific CQI may be transmitted separately from the NACK feedback.

[0023] In one example of any of the aforementioned exemplary aspects of the method, the method may further include determining at least one retransmission parameter, the at least one retransmission parameter being one of a retransmission rate, a modulation and coding scheme (MCS), a power level, a beamforming parameter, a number of retransmitted code blocks, or a number of check blocks.

[0024] In one example of any of the aforementioned exemplary aspects of the method, the transmission-specific CQI may correspond to a proposed retransmission rate, and the retransmission is performed using the proposed retransmission rate.

[0025] In one example of any of the aforementioned exemplary aspects of the method, the retransmission may include one or more retransmitted code blocks or one or more cross block check blocks generated from selected bits across one or more code blocks of the data transmission.

[0026] In another example aspect, the present disclosure describes a method in a receiver node, the method including receiving a data transmission of one or more code blocks from a transmitter node, performing a decoding operation to decode the one or more code blocks, determining channel coding related feedback based on the decoding operation, and transmitting the channel coding related feedback to the transmitter node.

[0027] In one example of the aforementioned exemplary aspect of the method, the channel coding related feedback may be determined based on hard decision outputs from a decoder at the receiver node generated from a decoding operation.

[0028] In another example of the aforementioned exemplary aspect of the method, the channel coding related feedback may be determined based on a soft output from a decoder at the receiver node, generated from a decoding operation.

[0029] In another example of the aforementioned exemplary aspect of the method, the channel coding related feedback may be determined based on the decoding convergence behavior of a decoder at a receiver node during a decoding operation.

[0030] In another exemplary aspect, the present disclosure describes an apparatus including a processing unit and a non-transitory memory including instructions that, when executed by the processing unit, cause the apparatus to perform any one of the preceding exemplary aspects of the method.

[0031] In another exemplary aspect, the present disclosure describes a non-transitory computer-readable medium having stored thereon machine-executable instructions that, when executed by a processing unit of an apparatus, cause the apparatus to perform any one of the aforementioned exemplary aspects of the method.

[0032] Reference will now be made, by way of example, to the accompanying drawings which illustrate exemplary embodiments of the present application. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 is a schematic diagram illustrating an example wireless communication system suitable for implementing examples described herein. [Diagram 2] FIG. 1 is a block diagram illustrating an example apparatus suitable for implementing the examples described herein. [Figure 3A] FIG. 1 illustrates an example code structure from which a cross-block check block may be generated. [Figure 3B] FIG. 1 illustrates an example code structure from which a cross-block check block may be generated. [Figure 3C] FIG. 1 illustrates an example code structure from which a cross-block check block may be generated. [Figure 4A] FIG. 1 is a signaling diagram illustrating an example of how CSI reporting is performed. [Figure 4B] FIG. 1 is a signaling diagram illustrating an example of how CSI reporting is performed. [Diagram 5]1 is a flowchart illustrating an example method for providing transmit-specific CQI feedback, in accordance with an example of the present disclosure. [Figure 6] FIG. 6 is a signaling diagram illustrating an exemplary implementation of the method of FIG. 5. [Figure 7] FIG. 2 illustrates an example CQI table that may be used to implement examples of the present disclosure. [Figure 8] FIG. 13 illustrates an example table of feedback indexes that may be used to implement examples of the present disclosure. [Figure 9] 1 is a flowchart illustrating an example method for providing channel coding related feedback, in accordance with an example of the present disclosure. [Figure 10] 10 is a signaling diagram illustrating an example implementation of the method of FIG. 9. [Figure 11] 4 is a flowchart illustrating an example method that may be performed by a transmitter node, in accordance with an example of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Similar reference numbers may be used in different figures to indicate similar components.

[0035] To facilitate an understanding of the present disclosure, an exemplary wireless communication system is first described.

[0036] FIG. 1 illustrates an example of a wireless communication system 100 (also referred to as wireless system 100) in which embodiments of the present disclosure may be implemented. In general, the wireless system 100 allows multiple wireless or wired elements to communicate data and other content. The wireless system 100 may allow content (e.g., voice, data, video, text, etc.) to be communicated (e.g., broadcast, narrowcast, via user device to user device, etc.) between entities of the system 100. The wireless system 100 may operate by sharing resources, such as bandwidth. The wireless system 100 may be suitable for wireless communication using 5G technology and / or later generation wireless technologies. In some examples, the wireless system 100 may also accommodate some legacy wireless technologies (e.g., 3G or 4G wireless technologies).

[0037] In the illustrated example, wireless system 100 includes user equipment (UE) 110, radio access network (RAN) 120, core network 130, public switched telephone network (PSTN) 140, Internet 150, and other networks 160. In some examples, one or more of the networks may be omitted or replaced with a different type of network. Other networks may be included in wireless system 100. Although a particular number of these components or elements are shown in FIG. 1, any reasonable number of these components or elements may be included in wireless system 100.

[0038] The UE 110 is configured to operate, communicate, or both in the wireless system 100. For example, the UE 110 may be configured to transmit, receive, or both over wireless or wired communication channels. The term "UE" may be used to refer to any suitable end-user device for wireless operations, and may include (or be referred to as) devices such as a wireless transmit / receive unit (WTRU), a mobile station, a mobile relay, a fixed or mobile subscriber unit, a mobile phone, a station (STA), a machine type communication (MTC) device, a personal digital assistant (PDA), a smartphone, a laptop, a computer, a tablet, a wireless sensor, an Internet of Things (IoT) device, a network-enabled vehicle, or a consumer electronics device, among others. In some examples, the term electronic device (ED) may be used in place of a UE. In general, it should be understood that the use of the term UE in this disclosure does not necessarily limit the disclosure to any particular wireless technology.

[0039] In Figure 1, the RAN 120 includes base stations (BSs) 170. Although Figure 1 illustrates each RAN 120 including a single respective BS 170, it should be understood that any given RAN 120 may include more than one BS 170 and any given RAN 120 may also include base station controllers (BSCs), radio network controllers (RNCs), relay nodes, elements, and / or devices. Each BS 170 is configured to wirelessly interface with one or more of the UEs 110 to enable access to any other BSs 170, the core network 130, the PSTN 140, the Internet 150, and / or other networks 160. For example, the BS 170 may also be referred to as (or include) a base transceiver station (BTS), a radio base station, a Node-B (NodeB), evolved NodeB (eNodeB or eNB), a Home eNodeB, a gNodeB (gNB) (also referred to as a next generation NodeB), a transmission point (TP), a transmission and reception point (TRP), a site controller, an access point (AP), or a wireless router, among others. Future generation BSs 170 may be referred to using other terminology. In some examples, the term TRP may be used to encompass the BS 170 or any other node that may assist in transmitting and receiving communications. Thus, while the present disclosure refers to the BS 170, it should be understood that this is not intended to be limiting. Any UE 110 may alternatively or additionally be configured to interface with, access, or communicate with any other BS 170, the Internet 150, the core network 130, the PSTN 140, other networks 160, or any combination thereof. In some examples, the BS 170 may access the core network 130 via the Internet 150 .

[0040] The UE 110 and the BS 170 are examples of communication devices that may be used to implement some or all of the functions and / or embodiments described herein. Any BS 170 may be a single element as shown, or multiple elements distributed across a corresponding RAN 120, or otherwise. Each BS 170 transmits and / or receives wireless signals within a particular geographic region or area, sometimes referred to as a "cell" or "coverage area." A cell may be further divided into cell sectors, and a BS 170 may use multiple transceivers, for example, to serve multiple sectors. In some embodiments, picocells or femtocells may be established and the radio access technology supports this. A macrocell may encompass one or more smaller cells. The number of RANs 120 shown is merely an example. Any number of RANs may be contemplated when conceiving the wireless system 100.

[0041] The BS 170 communicates with one or more of the UEs 110 through one or more uplink (UL) / downlink (DL) radio interfaces 190 (e.g., via radio frequency (RF), microwave, infrared, etc.). The UL / DL interfaces 190 may also be referred to as, for example, a UL / DL connection, a UE-BS link / connection / interface, or a UE-network link / connection / interface. The UEs 110 may also communicate with each other directly (i.e., without going through the BS 170) via one or more sidelink (SL) radio interfaces 195. The SL interfaces 195 may also be referred to as, for example, a SL connection, a UE-to-UE link / connection / interface, a vehicle-to-vehicle (V2V) link / connection / interface, a vehicle-to-everything (V2X) link / connection / interface, a vehicle-to-infrastructure (V2I) link / connection / interface, a vehicle-to-pedestrian (V2P) link / connection / interface, a device-to-device (D2D) link / connection / interface, or simply a SL. The radio interfaces 190, 195 may utilize any suitable radio access technology. For example, the radio system 100 may implement one or more channel access methods, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), or Single Carrier FDMA (SC-FDMA), for wireless communications.

[0042] The RAN 120 communicates with the core network 130 to provide various services, such as voice, data, and other services, to the UE 110. The RAN 120 and / or the core network 130 may communicate directly or indirectly with one or more other RANs (not shown), which may or may not be directly served by the core network 130 and may or may not employ the same radio access technology. The core network 130 may also serve as a gateway access between (i) the RAN 120 or the UE 110, or both, and (ii) other networks (such as the PSTN 140, the Internet 150, and other networks 160). In addition, some or all of the UE 110 may include functionality for communicating with different wireless networks over different wireless links using different wireless technologies and / or protocols. Instead of (or in addition to) wireless communication, the UE 110 may communicate with a service provider or switch (not shown) and the Internet 150 via wired communication channels. The PSTN 140 may include a circuit-switched telephone network for providing plain old telephone service (POTS). The Internet 150 may include a network of computers and / or subnets (intranets), and the Internet 150 may incorporate protocols such as the Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), etc. The UE 110 may be a multi-mode device capable of operating according to multiple radio access technologies and may incorporate multiple transceivers necessary to support these.

[0043] 2 illustrates an example apparatus 200 that may implement examples disclosed herein. FIG. 2 illustrates possible embodiments of the UE 110 or the BS 170 and is not intended to be limiting.

[0044] As shown in FIG. 2, the exemplary apparatus 200 (e.g., an exemplary embodiment of the UE 110 or BS 170) includes at least one processing unit 201. The processing unit 201 implements various processing operations of the apparatus 200. For example, the processing unit 201 may perform signal coding, data processing, power control, input / output processing, or any other function of the apparatus 200. The processing unit 201 may also be configured to implement some or all of the functions and / or embodiments described in more detail herein. Each processing unit 201 includes any suitable processing or computing device configured to perform one or more operations. Each processing unit 201 may include, for example, a microprocessor, a microcontroller, a digital signal processor, a field programmable gate array, or an application specific integrated circuit.

[0045] The device 200 includes at least one communication interface 202 for wired and / or wireless communication. One or more communication interfaces 202 may be used in the device 200. Each communication interface 202 includes any suitable structure for generating signals for wireless or wired transmission and / or for processing wirelessly or wired received signals. Although shown as a single functional unit, the communication interface 202 may be implemented using at least one transmitter interface and at least one separate receiver interface. In some examples, one or more transmitters and one or more receivers may be implemented by the communication interface 202.

[0046] The apparatus 200 includes one or more antennas 204 for wireless communication. Each antenna 204 includes any suitable structure for transmitting and / or receiving wireless signals. In some examples, the apparatus 200 may include multiple antennas 204 to support multiple-input multiple-output (MIMO) communication. There may be multiple antennas 204 that together form an antenna array that may be used for beamforming and beamsteering operations. In some examples, there may be one or more antennas 204 used to transmit signals and separate one or more antennas 204 used to receive signals.

[0047] The apparatus 200 further includes one or more input / output devices 206 or input / output interfaces (such as a wired interface to the Internet 150). The input / output devices 206 enable interaction with a user or other devices in the wireless system 100. Each input / output device 206 includes any suitable structure for providing information to or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touch screen, including network interface communications.

[0048] In addition, the device 200 includes at least one memory 208. The memory 208 stores instructions and data used, generated, or collected by the device 200. For example, the memory 208 may store software instructions or modules configured to implement some or all of the functions and / or embodiments described herein and executed by the processing unit 201. Each memory 208 includes any suitable volatile and / or non-volatile storage and retrieval device. Any suitable type of non-transitory memory may be used, such as random access memory (RAM), read-only memory (ROM), hard disk, optical disk, subscriber identity module (SIM) card, memory stick, and secure digital (SD) memory card.

[0049] Hybrid Automatic Repeat Request (HARQ) is a commonly used retransmission technique. Conventional HARQ retransmission schemes are typically based on whether a transport block (TB) is successfully decoded by a receiver node. If the receiver node fails to decode any one of the code blocks (CBs) of a packet (when the packet can be a single TB), negative feedback is sent back to the transmitter node, and the transmitter node performs a retransmission of the entire packet, even if other CBs of the packet are successfully decoded by the receiver node. This can be an inefficient use of communication resources. New Radio (NR) Release 15 supports Code Block Group (CBG) based HARQ retransmission. In CBG based HARQ retransmission, CBs are grouped into CBGs, and feedback from the receiver node includes the index of the CBG that contains the successfully decoded CB. Retransmission can then be based only on the CBG with the index indicated in the feedback. However, CBG based HARQ retransmission requires the feedback to include the CBG index that needs to be retransmitted, which increases the overhead of HARQ feedback. Furthermore, if each CBG has one (or more) CBs in error, then all CBGs (i.e., the entire TB) are used for retransmission, thus eliminating the savings in retransmission in addition to the additional overhead of needing to feed back the CBG index. Thus, CBG-based HARQ can still introduce inefficiencies.

[0050] Retransmission schemes based on the use of cross-block check blocks (also referred to as cross-packet check blocks or vertical check blocks) have been described. For example, techniques for generating cross-block check blocks are described in U.S. patent application Ser. No. 16 / 665,121, filed Oct. 28, 2019, entitled “SYSTEM AND METHOD FOR HYBRID-ARQ,” which is incorporated herein by reference in its entirety. The use of cross-block check blocks in network coding (also referred to as 2D network coding or 2D joint network coding) is described in U.S. patent application Ser. No. 17 / 110,226, filed Dec. 2, 2020, entitled “METHODS AND SYSTEMS FOR NETWORK CODING USING CROSS-PACKET CHECK BLOCKS,” which is incorporated herein by reference in its entirety.

[0051] An example of how a cross-block check block may be generated will now be described with reference to Figures 3A-3C.

[0052] FIG. 3A illustrates an exemplary code structure of a single packet 302 (which may be one TB) segmented into multiple CBs 310 (four CBs 310 are shown in this example for simplicity, but this is not intended to be limiting). Each CB 310 includes an information block 304 formed from encoder input bits. The encoder input bits may also be referred to as information bits. Each CB 310 also includes check bits (e.g., cyclic redundancy check (CRC) bits) that are generated using bits from the information block 304 of the CB 310. The check bits appended to the information block 304 of the CB 310 may be referred to as a horizontal check block 306. As illustrated, there may be one horizontal check block 306 for each CB 310. The term "horizontal" refers to how the check bits in the horizontal check block 306 are generated using only information bits from a single CB 310 and is not intended to imply any physical structure or orientation. The horizontal check block 306 may also be referred to as an intra-block check block, or a single CB check block, among others.

[0053] One or more cross block check blocks 308 are generated using selected bits across two or more CBs 310. In some examples, the cross block check blocks 308 may be referred to as vertical check blocks (to distinguish them from the horizontal check blocks 306), although the term "vertical" is not intended to imply any physical structure or orientation. Additionally, it should be understood that the terms "parity block" or "redundancy block" may be used in place of "check block." In FIG. 3A, each cross block check block 308 is generated using selected bits across two or more CBs 310 of the packet 304.

[0054] 3B illustrates another example, which is similar to the example of FIG. 3A, except that FIG. 3B illustrates two different packets 302, and the cross block check block 308 is generated using selected bits across the CBs of the two different packets 302. Although two packets 302 are illustrated, it should be understood that there may be more packets 302. Thus, FIG. 3B illustrates an example in which each cross block check block 308 is generated using selected bits across the CBs 310 of two or more packets 302. In this example, the cross block check block 308 may be referred to as a cross packet check block (because the cross block check block 308 is generated using selected bits across the two or more packets 302).

[0055] FIG. 3C shows another example of how the cross block check block 308 is generated from a non-systematic code (e.g., a polar code, a block code, or a convolutional code). The packet 302 is segmented into multiple CBs 310, each CB 310 being a non-systematic codeword 312. Each non-systematic codeword is determined based on a set of encoder input bits, but the information bits do not appear in the codeword as systematic bits. Unlike systematic codes, the horizontal check bits are not simply appended to the set of information bits. In this example, a single packet 302 is shown, but it should be understood that there may be more than one packet 302 (each packet 302 includes a CB 310 with a non-systematic codeword 312). In this example, each cross block check block 308 is generated using selected bits from two or more CBs 310.

[0056] It will be understood by those skilled in the art that the present disclosure does not depend on whether a systematic or non-systematic code is used. For simplicity, the following description may be based on a packet 302 having a systematic CB 310. It should be understood that this is not intended to be limiting.

[0057] When systematic CB 310 is used, cross block check block 308 may include one or more cross block check blocks 308 generated from bits selected from the plurality of information blocks 304. Optionally, one or more cross block check blocks 308 may also be generated using bits selected from across the plurality of horizontal check blocks 306. A cross block check block 308 generated from bits selected from a horizontal check block may be referred to as a "check-on-check" block.

[0058] Generally, in each of Figures 3A-3C, each cross block check block 308 is generated from bits selected from multiple CBs 310. In particular, one or more bits may be selected from each of two or more CBs 310. The selected bits may be referred to as cross block bits (because the bits are selected across multiple CBs 310), and the group of selected bits may be referred to as a cross block information block. The cross block information blocks are then encoded (e.g., using an FEC code such as an LDPC code) or otherwise combined (e.g., using an XOR, a linear combination, etc.) to obtain the cross block check block 308. In general, the term check block should be understood to encompass various techniques that may be used to combine selected bits across different CBs 310, including encoding techniques such as using XOR and using linear combination, as well as encoding the selected bits using a channel code (among others).

[0059] When the CBs 310 are arranged in rows, as shown in FIGS. 3A-3C, each cross block check block 308 may be generated from a string of bits, which may have any suitable width (e.g., may be one or more bits wide). Different cross block check blocks 308 may be generated from strings of different bit widths (i.e., different numbers of cross block bits may be used to generate different cross block check blocks 308). In some examples, each CB 310 may be divided into an equal (or nearly equal) number of bits, called sub-blocks. Each cross block check block 308 may then be generated from bits belonging to a respective column of the sub-block.

[0060] The set of cross block check blocks 308 may be generated based on the bits of the CB 310 in natural order. The natural order of the bits may refer to the order of the bits in each CB 310 as output by the encoder. The different sets of cross block check blocks 308 may be generated by shuffling (or interleaving) the bits in each CB 310 (such that the vertical column of bits obtained after shuffling or interleaving is different from the vertical column of bits obtained when the bits of the CB 310 are in natural order). A predefined shuffling scheme or a predefined interleaver may be used to perform this shuffling or interleaving. The interleaver may be (among other things) a predefined algorithm, or a predefined matrix, which is applied to rows of bits to obtain reordered rows of bits. It is understood that other techniques (not necessarily limited to interleaving) may be used. Thus, different sets of cross block check blocks 308 may be generated for the same set of CBs 310 using natural ordering of bits or using different interleavers (when different interleavers are associated with each different redundancy version (RV) index). Examples of how each RV index may be associated with a respective interleaver used to generate the cross block check blocks 308 are described in PCT Application No. PCT / CN2021 / 121483, “METHODS AND APPARATUSES FOR WIRELESS COMMUNICATION RETRANSMISSION USING CHECK BLOCKS GENERATED ACCORDING TO SUBBLOCK INTERLEAVERS,” filed on September 28, 2021, and incorporated herein by reference in its entirety.

[0061] The manner in which the cross block bits are selected (e.g., which interleaver or RV index to use, how many bits to select across different CBs 310, from which CBs 310 to select the cross block bits, etc.) and the manner in which the cross block check blocks 308 are generated (e.g., which combining or encoding technique to use, how many cross block check blocks 308 to generate, whether check-on-check blocks are generated, etc.) may be configured by the transmitter node and / or by the network controller and / or may be defined by the standard.

[0062] The check bits included in the horizontal check block 306 and the cross block check block 308 may be useful to aid in decoding at a receiver node. For example, after each decoding operation (also called a decoding attempt) at a decoder, an error check may be performed using the check bits to determine whether the information bits in the CB 310 were successfully decoded. Each cross block check block 308 includes check bits generated from multiple CBs 310, thereby providing information useful for decoding the multiple CBs 310. The decoder may use the check bits of the cross block check block 308 to aid in decoding the CBs 310.

[0063] In examples where the CB 310 is systematic (such as an LDPC code or a turbo code), an iterative decoding process may be used in the decoder of the receiver node to decode the received CB 310. The decoder calculates the log-likelihood ratio (LLR) of the bit values ​​during the decoding of the CB 310, which may be considered as a "soft" output of the decoder. In this disclosure, a soft output may refer to a decoder output that has not yet been finalized (e.g., a bit value that has not yet been definitively determined to be a 1 or 0 value), but may still provide information that may be useful (e.g., in a subsequent decoding iteration). Such a soft output may be probabilistic in nature (e.g., an LLR). CBs 310 that are not correctly decoded (e.g., fail a check using the corresponding horizontal check block 306) may benefit from information encoded in the cross block check block 308. Because each of the cross block check blocks 308 is generated from information bits selected from two or more (or all) of the CBs 310, the soft output from a decoding operation to decode the cross block check blocks 308 may help improve the decoding of the CBs 310 (and vice versa). In at least this way, the cross block check blocks 308 help improve the decoding.

[0064] A HARQ retransmission scheme that utilizes a cross block check block may be referred to as cross block HARQ or 2D HARQ. A HARQ retransmission scheme that does not utilize a cross block check block may be referred to as conventional HARQ or 1D HARQ. This disclosure describes an example feedback mechanism that may be used in both conventional HARQ and cross block HARQ. The disclosed feedback mechanism may enable a receiver node to provide information regarding the quality of an initial transmission to a transmitter node to enable the transmitter node to determine an appropriate amount of redundancy (e.g., code rate) to be used in the retransmission (rather than using the same code rate as the initial transmission). This provides the advantage that retransmission resources required for the retransmission may be reduced while maintaining overall reliability.

[0065] In existing LTE and NR wireless communication systems, channel quality indicator (CQI) feedback is part of channel state information (CSI) feedback. CSI feedback typically includes, among other information, a rank indicator (RI), a precoding matrix indicator (PMI), and a CQI. For a given corresponding rank and precoding matrix, the CQI indicates the maximum modulation and coding scheme (MCS) that the channel quality can support.

[0066] CSI feedback including CQI feedback is typically transmitted in a CSI report transmitted on a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). The CSI report may be periodic, semi-persistent, or aperiodic. The periodicity of the periodic CSI report is configured. Semi-persistent CSI reporting is similar to periodic CSI reporting, but additionally CSI reporting may be enabled and disabled (e.g., using a MAC control element (CE)). Aperiodic CSI reporting means that each CSI report is explicitly triggered (e.g., using downlink control information (DCI) signaling or MAC CE).

[0067] FIG. 4A is a signaling diagram illustrating an example of an exemplary periodic or semi-persistent CSI reporting.

[0068] The BS 170 transmits a radio resource control (RRC) signal 402 to the UE 110 to configure resources used for CSI reporting (including CSI reference signals (CSI-RS)). Optionally, if semi-persistent CSI reporting is used, the BS 170 may transmit an enablement signal 404 to the UE 110 (e.g., using MAC CE). The BS 170 transmits a CSI-RS 406 to the UE 110. The UE 110 uses the CSI-RS to perform measurements and calculate a signal-to-interference-and-noise ratio (SINR). The UE 110 determines the highest MCS that the calculated SINR supports and the corresponding CQI index (e.g., using a CQI table that may be defined in a standard). The CQI index is the CQI feedback included in the CSI report 408 sent back to the BS 170 by the UE 110. The CSI-RS 406 and the CSI report 408 are repeated periodically. Optionally, if semi-persistent CSI reporting is used, the periodic CSI reporting may end after the BS 170 transmits a disable signal 410 to the UE 110 (eg, using the MAC CE).

[0069] FIG. 4B is a signaling diagram illustrating an example of a typical aperiodic CSI report.

[0070] The BS 170 sends a radio resource control (RRC) signal 422 to the UE 110 to configure resources used for CSI reporting (including CSI-RS). Optionally, the BS 170 may trigger aperiodic CSI reporting in an UL scheduling grant 424. The BS 170 then sends a CSI-RS 426 to the UE 110. The UE 110 uses the CSI-RS to obtain the SINR and reports the corresponding CQI index in a CSI report 428 (similar to the procedure described above for periodic or semi-persistent CSI reporting). In aperiodic CSI reporting, the CSI-RS 426 and the CSI report 428 are not performed again (until the next trigger from the BS 170).

[0071] In some examples, instead of using CSI-RS, a synchronization signal block (SSB) may be used instead. In general, the BS 170 uses the received CQI feedback (contained in the CSI report) for link adaptation, which means that the BS 170 can use the CQI feedback to select the appropriate MCS to be used for transmission. However, regardless of the specific type of CSI report used, there is typically a relatively long time interval (e.g., about 1 ms) between each CSI report (and thus a relatively long time interval between each CQI feedback). This means that the information contained in the conventional CQI feedback does not necessarily accurately reflect the rapidly changing channel quality. Furthermore, conventional CQI measurements are relatively coarse measurements of channel quality, and in particular, conventional CQI measurements are only made at specific slots and bandwidths (e.g., depending on the CSI-RS or SSB used) and provide information about the general channel, not a specific transmission. In addition, in wireless mobile communications, the channel changes over time. Thus, conventional CQI feedback may not provide an accurate indication of the code rate supported for an actual transmission (e.g., due to interference, channel aging, etc.). In most existing cellular communication applications, conventional CQI feedback may be considered sufficient for typically slow link adaptation.

[0072] In various examples, the present disclosure describes feedback mechanisms that provide information to enable a transmitter node (e.g., a BS) to determine a retransmission rate based on the quality of an initial transmission received at a receiver node. The disclosed transmit-specific CQI feedback allows for faster adaptation of transmission parameters, which may be important in high data volume applications (e.g., involving transmission of larger TBs with many code blocks). The disclosed transmit-specific CQI feedback may enable more efficient use of time / frequency resources while introducing relatively little overhead.

[0073] In some examples, the receiver node may provide feedback based on dynamic channel measurements performed using the initial transmission. The dynamic channel measurements performed by the receiver node may be measurements of channel quality, power or energy of the transmitted signal, among others. One example of a channel quality measurement, which will be described further below, is CQI feedback based on measurements performed using the initial transmission. Such CQI feedback may be referred to as transmission-specific CQI feedback, instantaneous CQI feedback, or dynamic CQI feedback (or other similar suitable names) to distinguish it from conventional slower CQI feedback.

[0074] In another example, a receiver node may provide feedback based on the decoding operations performed to decode the initial transmission. Such feedback may be referred to as decoding-based feedback.

[0075] In another example, the receiver node may provide feedback based on an estimate of the retransmission rate / resources that may be needed to successfully decode the initial transmission. The estimate of the needed retransmission rate / resources (which may be quantized over a defined number of bits or a defined number of possible selections) may be based on dynamic channel measurements and / or decoding operations.

[0076] In this disclosure, transmit-specific CQI feedback refers to CQI feedback that may be determined from a reference signal included in a transmission (e.g., an initial transmission). The transmit-specific CQI feedback may be used to indicate the highest MCS that can be supported by the current channel while keeping the BLER below a given threshold. For example, as described in more detail below, the transmit-specific CQI feedback may be determined using a CQI table (which may be an existing CQI table used for conventional CQI feedback). In another example, the transmit-specific CQI feedback may be determined using a CQI table specific to the transmit-specific CQI feedback.

[0077] FIG. 5 is a flow chart illustrating an example method 500 that may be performed by a receiver node apparatus 200 (eg, UE 110) to provide transmit-specific CQI feedback back to a transmitter node (eg, BS 170).

[0078] At 502, one or more CB transmissions (and more specifically, data transmissions) are received from a transmitter node. For example, the transmission may be an initial transmission, where the CB corresponds to a data packet from the transmitter node or a transport block transmitted by the transmitter node. The data transmission includes a transmission of an associated reference signal, for example, a demodulation reference signal (DMRS).

[0079] Optionally, at 504, a decoding operation (also referred to as a decoding attempt) is performed to decode one or more CBs. If the decoding is successful (i.e., all received CBs are decoded), the receiver node may provide an acknowledgement (ACK) as feedback to the transmitter node instead of the transmit-specific CQI feedback. As described further below, in some examples, a reserved CQI index value may be used for the transmit-specific CQI feedback to indicate an ACK (i.e., the ACK feedback may be incorporated into the transmit-specific CQI feedback). In some examples, the transmit-specific CQI feedback (apart from the reserved CQI index value indicating an ACK) may be interpreted as a form of a negative acknowledgement (NACK) to indicate that the decoding of at least one CB was not successful.

[0080] In some examples, the transmission-specific CQI feedback may be provided independent of the decoding operation. That is, the transmission-specific CQI feedback may be feedback provided separately from the ACK / NACK feedback, regardless of whether the decoding of the received code block was successful or unsuccessful. In this regard, the method 500 may omit step 504. That is, the decoding operation may occur at any time, but steps 506 and 508 may not depend on the result of the decoding operation. Furthermore, steps 506 and 508 may be performed before or in parallel with the decoding operation. Thus, the method 500 may be performed without performing any decoding of the at least one code block.

[0081] At 506, a transmission-specific CQI is determined for the received transmission using a reference signal (e.g., DMRS) included in the transmission. For example, the transmission-specific CQI indicates the highest MCS (e.g., determined from a CQI table) that a channel having a BLER less than a given threshold can support, as described in further detail later in this disclosure. To determine the transmission-specific CQI, the receiver node may obtain a SINR using the reference signal and then determine a CQI value based on the SINR. Existing techniques used to determine a traditional slower CQI may be adapted to determine the transmission-specific CQI, as disclosed herein.

[0082] At 508, feedback indicative of the transmission-specific CQI is transmitted to the transmitter node. The feedback may be provided as ACK / NACK feedback or may be provided separately from the ACK / NACK feedback (e.g., on a separate or dedicated feedback channel).

[0083] A transmitter node (e.g., BS 170) may use the transmit-specific CQI feedback to determine how the retransmission should be performed, e.g., the transmitter node may determine the code rate, number of cross block check blocks (if cross block check blocks are used), MCS, power level, beamforming, etc., to use for the retransmission based on the transmit-specific CQI feedback. The transmitter node may perform the retransmission using a set of one or more cross block check blocks, as described above. In another example, the transmitter node may perform the retransmission using a conventional HARQ scheme (i.e., without generating cross block check blocks).

[0084] The receiver node may receive a retransmission from the transmitter node following the transmitter node determining the retransmission parameters using the transmit-specific CQI feedback. The transmitter node may use the transmit-specific CQI feedback to immediately adapt the retransmission parameters, so that the retransmission may use different parameters (e.g., different MCS, different time-frequency resources, etc.) than the initial transmission. For example, if the initial transmission used a particular MCS, the transmitter node may adapt the retransmission parameters to use a different MCS for the retransmission. Thus, the transmit-specific CQI allows for dynamic or instantaneous adaptation of the retransmission parameters, which may be more sensitive to changing channel conditions compared to traditional slower CQI feedback.

[0085] It should be understood that the method 500 may be similarly performed by a receiver node to provide transmission-specific CQI feedback in response to a retransmission (i.e., the transmission-specific CQI feedback is not necessarily limited to the initial transmission). For example, if the receiver node is still unable to decode all CBs after a retransmission from the transmitter node, the receiver node may determine a transmission-specific CQI and send transmission-specific CQI feedback back to the transmitter node as a form of NACK (or in addition to a separate NACK feedback) to indicate that the decoding was still unsuccessful. The transmitter node may then use the transmission-specific CQI feedback to determine how a second retransmission should be performed. The method 500 may be performed, for example, until all of the CBs in the initial transmission are successfully decoded by the receiver node or until a maximum number of retransmissions are performed by the transmitter node.

[0086] 6 is a signaling diagram illustrating an example of transmit-specific CQI feedback, for example, by implementing an embodiment of the method 500 at a receiver node. It should be understood that in this example, the transmitter node is the BS 170 and the receiver node is the UE 110 (i.e., downlink transmission), but this is not intended to be limiting. For example, in another example, the transmitter node may be the UE 110 and the receiver node may be the BS 170 (i.e., uplink transmission). In another example, the transmitter node may be the first UE 110 and the receiver node may be the second UE 110 (i.e., sidelink transmission).

[0087] The BS 170 transmits a scheduling 602 for the initial transmission to the UE 110. For example, the DL scheduling for the initial transmission may be transmitted in a DCI signal. The BS 170 then performs a downlink data transmission 604 (i.e., an initial transmission including one or more CBs) to the UE 110. In particular, the transmission includes a reference signal such as a DMRS. The UE 110 receives the transmission (e.g., as described in steps 502 and 504 of the method 500) and performs a decoding operation to decode the one or more CBs in the initial transmission. In this example, at least one code block is not necessarily decoded, and the UE 110 returns a HARQ feedback (e.g., a NACK feedback) and a transmission-specific CQI feedback 606. In particular, the UE 110 may determine a transmission-specific CQI feedback using the DMRS from the initial transmission (as described in steps 506 and 508 of the method 500) and may transmit the transmission-specific CQI feedback to the BS 170 together with (or instead of) the HARQ feedback via the PUCCH.

[0088] At 608, BS 170 can use the information in the transmit-specific CQI feedback to adapt transmission parameters (e.g., code rate, number of cross block check blocks (if cross block check blocks are used), MCS, power level, beamforming, etc.) for performing the retransmission. BS 170 schedules retransmission 610 (e.g., by transmitting another DCI signal) and performs a downlink retransmission including DMRS 612. In particular, the retransmission is performed using transmission parameters that have been adapted based on the transmit-specific CQI feedback from UE 110. UE 110 then performs decoding again using additional information from the retransmission. If the decoding is still unsuccessful, UE 110 can send back transmit-specific CQI feedback along with (or instead of) the NACK feedback, and BS 170 can perform another retransmission (with adaptation of the transmission parameters according to the transmit-specific CQI feedback). This process can be repeated until decoding of all code blocks at UE 110 is successful or until a maximum number of retransmissions is reached. Assuming that all code blocks are successfully decoded (after one or more retransmissions), UE 110 may optionally send HARQ feedback 614 (eg, ACK feedback) back to BS 170.

[0089] From the above description and examples, it will be understood that the transmit-specific CQI feedback (also referred to as dynamic CQI feedback or instantaneous CQI feedback) disclosed herein differs from conventional CQI feedback in several ways. For example, compared to conventional CQI feedback, there is no need to configure the reference signal resources used for CQI reporting, rather the transmit-specific CQI feedback utilizes the existing configuration and scheduling of DMRS resources (already used with data transmissions for channel estimation purposes). The transmit-specific CQI feedback may not need to be explicitly triggered (e.g., unlike the case of semi-persistent or aperiodic CSI reporting), rather the transmit-specific CQI feedback may be transmitted simultaneously with the existing HARQ feedback on the PUCCH (e.g., the receiver node may always transmit the transmit-specific CQI feedback by default). However, in some examples, the signaling (e.g., scheduling DCI) may include an indicator to indicate to the receiver node whether transmit-specific CQI feedback should be provided for the scheduled data transmission.

[0090] Furthermore, conventional CQI feedback in CSI reports is based on a reference signal of a particular bandwidth (e.g., wideband or subband) and resource, and is not associated with any particular transmission. However, the transmission-specific CQI feedback disclosed herein is specifically based on measurements obtained from a particular actual transmission (e.g., a DMRS associated with a data transmission). Thus, compared to conventional CQI feedback, the transmission-specific CQI feedback disclosed herein is a more accurate estimate of the channel quality experienced by the receiver node based on the actual received transmission. Thus, the transmission-specific CQI feedback can more accurately predict the code rate supported by the current channel and the amount of retransmission resources required to successfully decode the transmitted code block.

[0091] For example, if the initial transmission includes multiple code blocks and the transmitter node uses cross block check blocks in the retransmission, the overall code rate supported by the current channel, as indicated by the transmit-specific CQI feedback, may provide a good estimate of how much additional redundancy is needed in the retransmission (and thus how many cross block check blocks to generate). In another example, if the transmitter node is BS 170, information from the transmit-specific CQI feedback may be used for link adaptation (e.g., to determine the MCS to use for the retransmission). In addition, the transmitter node (e.g., BS 170) may adjust the time / frequency resources used for the retransmission, thus helping to reduce retransmission overhead and / or improve spectral efficiency. It should be appreciated that the transmitter node (e.g., BS 170) may use information from the transmit-specific CQI feedback to adjust any other parameters for any subsequent transmissions. For example, BS 170 may adjust power control parameters based on the transmit-specific CQI feedback, or BS 170 may determine that the required redundancy in the retransmission is low, such that new data may be transmitted along with the retransmission, based on the transmit-specific CQI feedback.

[0092] As mentioned above, in some examples, the transmission-specific CQI may be determined based on a measurement of SINR using a reference signal, such as DMRS in the transmission. In another example, in addition to the transmission-specific CQI feedback, information on a measured power or energy level (e.g., Reference Signal Received Power (RSRP), Received Signal Strength Indicator (RSSI), L1-RSRP, etc.) may be provided. The power or energy measurement may be performed using a reference signal that is not necessarily part of the transmission (i.e., without necessarily using DMRS in the transmission). For example, the power or energy measurement may be performed using a latest reference signal that is not necessarily part of the transmission (e.g., CSI-RS, SSB, etc.). It should be noted that measurements performed using a reference signal that is not necessarily part of the transmission may result in measurements that reflect the current channel conditions with less accuracy than measurements performed using DMRS transmitted as part of the actual transmission.

[0093] In the above examples, the transmission-specific CQI feedback may be transmitted together with the HARQ feedback (e.g., ACK / NCK feedback) or may be transmitted on a separate or dedicated feedback channel. For example, if the transmission-specific CQI feedback is based on a downlink transmission (e.g., from the BS 170 to the UE 110 as shown in FIG. 6), the transmission-specific CQI feedback may be transmitted together with the HARQ feedback as part of the uplink control information (UCI) on the PUCCH. In some examples, the conventional ACK feedback may be incorporated into the transmission-specific CQI feedback. That is, a particular CQI index value (e.g., a CQI index value representing the best channel quality) in the transmission-specific CQI feedback may be used to indicate an ACK, while all other CQI index values ​​represent a NACK (as well as provide additional information regarding the channel quality). In some examples, the transmission-specific CQI feedback may be transmitted on the PUSCH (e.g., possibly together with other uplink data transmissions) or on a separate dedicated feedback channel.

[0094] Similarly, if the transmit-specific CQI feedback is based on an uplink transmission (e.g., from the UE 110 to the BS 170), the transmit-specific CQI feedback may be transmitted on a DCI of a physical downlink control channel (PDCCH) or a dedicated uplink feedback channel (e.g., similar to a physical channel Hybrid ARQ Indicator Channel (PHICH)). If the transmit-specific CQI feedback is based on a sidelink transmission (e.g., between two UEs 110), the transmit-specific CQI can be transmitted together with the HARQ feedback on a sidelink feedback channel (e.g., on a physical sidelink feedback channel (PSFCH)) or separately from the HARQ feedback on a separate sidelink feedback channel.

[0095] Quantization of the transmit-specific CQI feedback may be performed. Quantization may be useful to reduce the overhead introduced by the transmit-specific CQI feedback to more efficiently use feedback resources. In addition, quantization may reduce the number of possible CQI index values ​​used for the transmit-specific CQI feedback to fit within a predefined number of bits (e.g., based on available feedback resources). Several example methods for quantization of the transmit-specific CQI feedback are described herein. However, it should be understood that various different quantization methods known in the art may be used within the scope of this disclosure.

[0096] In some examples, the transmit-specific CQI feedback may utilize an existing CQI table (e.g., as described below with respect to FIG. 7) that is already used for conventional CQI feedback. While it may be convenient to adapt the use of a CQI index from an existing CQI table for the transmit-specific CQI feedback, it should be understood that this transmit-specific CQI feedback may be transmitted in other manners. For example, the transmit-specific CQI feedback may be transmitted as a measurement of channel quality (e.g., post-processing SINR value), maximum supported rate, maximum supported MCS, etc. The transmit-specific CQI feedback may be quantized in various ways to fit a selected number or number of bits used to represent the feedback.

[0097] In some examples, the transmit-specific CQI feedback may depend on some other parameters, such as the rank and precoder matrix used for the MIMO transmission (similar to conventional CSI reporting). However, parameters such as RI or PMI may not need to be reported together with the transmit-specific CQI feedback. Instead, the transmit-specific CQI feedback may be understood to be based on the actual rank and precoder matrix used for the data transmission for which the transmit-specific CQI feedback is determined.

[0098] In one example, the transmit-specific CQI feedback may be quantized based on an existing MCS table, similar to how conventional CQI feedback is used for link adaptation.

[0099] FIG. 7 shows an example CQI table 700, as defined in existing standards: 3GPP TS 38.214 Table 5.2.2.1-2: 4-bit CQI table.

[0100] As shown in FIG. 7, the CQI table 700 defines 16 possible CQI index values ​​(0 to 15), each corresponding to a respective modulation (Quadrature Phase Shift Keying (QPSK), 16-point Quadrature Amplitude Modulation (16QAM), or 64-point QAM (64QAM)), an approximate supported code rate, and a spectral efficiency (number of information bits per symbol). The supported code rate means that a transmission using the MCS corresponding to the CQI index value (and in the corresponding transmission resource) can provide a block error rate (BLER) less than a given threshold (e.g., set to 0.1 in this example). It should be noted that there are different CQI tables defined in the standard. Furthermore, the CQI table used to report CQI is usually different from the MCS table used for scheduling, since the CQI index table usually has fewer MCS entries than the MCS table used to schedule the actual transmission.

[0101] CQI table 700 (or other existing CQI tables) may be adapted for use with the transmit-specific CQI feedback disclosed herein. To further reduce feedback overhead, the number of bits required to indicate a CQI index value may be further reduced (e.g., by reducing the number of possible CQI index values). In some examples, there may be a different additional CQI table defined for transmit-specific CQI feedback (rather than using an existing CQI table such as CQI table 700). For example, a CQI table defined for transmit-specific CQI feedback may have fewer MCS entries compared to an existing CQI table, which corresponds to a smaller number of bits required to transmit transmit-specific CQI feedback. Such a CQI table may be predefined (e.g., defined in a standard and preprogrammed for the network and UE 110) or signaled by the network to UE 110 (e.g., via RRC signaling or DCI signaling).

[0102] In one example, the transmission-specific CQI feedback may indicate a differential CQI (or delta CQI), which is the difference in channel quality between the currently measured channel quality and the previously reported channel quality. The previously reported channel quality may be indicated by the previous transmission-specific CQI feedback or may be indicated by the conventional CQI feedback in the latest CSI report. For example, if the transmission-specific CQI feedback utilizes the same CQI table as the previous conventional CQI feedback in the latest CSI report, the transmission-specific CQI feedback may indicate the differential CQI as a supported MCS (e.g., as the difference between the highest supported MCS that can be supported by the currently measured channel quality and the actual MCS used for the received transmission). For example, if the previous conventional CQI feedback indicates a first CQI index (representing a first supported MCS) from the CQI table, the differential CQI may be indicated as the difference between a second CQI index (representing a second supported MCS) and the first CQI index, where the second CQI index is determined using the DMRS from the transmission. In another example, the differential CQI may be indicated as the difference between the currently used MCS (e.g., the MCS used for the current transmission) and the MCS supported by the current channel quality (i.e., determined using the DMRS from the current transmission). For example, the currently used MCS may correspond to a CQI index in a CQI table (or may be rounded to the closest MCS in the CQI table), and the differential CQI may then be the difference between the CQI index of the currently used MCS and the CQI index determined from the DMRS of the current transmission.

[0103] In some examples, the transmit-specific CQI feedback may be quantized by directly quantizing the determined CQI value (e.g., post-processing SINR value). In another example, the transmit-specific CQI feedback may be quantized based on the supported retransmission rates, which may allow the transmitter node to more directly select the rate used for retransmission (although in general it may be up to the transmitter node or BS 170 to determine how to use the information included in the transmit-specific CQI feedback).

[0104] If an existing CQI table is used for the transmit-specific CQI feedback, the receiver node (e.g., UE 110) performs operations to determine the transmit-specific CQI feedback by measuring and calculating the SINR using the DMRS from the received transmission. Then, from the SINR, the receiver node determines the highest supported MCS, identifies a corresponding CQI index value from the CQI table, and sends back the identified CQI index value as the transmit-specific CQI feedback. As mentioned above, in some examples, one of the possible CQI index values ​​(e.g., the CQI index corresponding to the highest channel quality) may be reserved to indicate ACK feedback.

[0105] There are different techniques that may be used by the receiver node to measure and calculate the SINR. One example of how the receiver node may measure and calculate the SINR to determine the transmit-specific CQI feedback is now described.

[0106] For example, the receiver node may perform channel estimation using pilots (e.g., DMRS in the received transmission). Then, post-processing SNIR estimation may be performed, and finally, the effective SINR may be estimated (e.g., using Exponential Effective SINR Mapping (EESM) or Capacity Effective SINR Mapping (ESM) similar to those used in the PHY abstraction). The effective SINR (SINR eff The formula for estimating θ is provided below:

number

[0107] The receiver node may then use the calculated effective SINR to match against the reference BLER curve for each MCS in the CQI table to determine the highest supported MCS that still has a BLER less than a set threshold (e.g., 0.1). Upon determining the highest supported MCS, a corresponding CQI index may be identified from the CQI table, and the receiver node may then feed back the identified CQI index as transmission-specific CQI feedback.

[0108] In another example, the transmit-specific CQI feedback may indicate a maximum supported rate. The receiver node may perform a supported rate estimation (e.g., R=BW log 1 where R is the supported rate, BW is the bandwidth, and SINR is the equivalent SINR, as described above). 2 The estimated supported rate may be further adjusted based on the modulation and other parameters. The receiver node may then compare the estimated supported rate with the actual transmission rate (based on the received transmission) to estimate the required transmission rate for retransmission. The estimated required transmission rate may then be indicated in the transmission-specific CQI feedback.

[0109] FIG. 8 shows an example table 800 of CQI index values ​​that may be used to indicate an estimated required transmission rate.

[0110] In this example, it may be assumed that the data transmission is a TB containing 12 CBs, with a given transmission rate (denoted by R) and 2-bit feedback is used (corresponding to 4 possible feedback index values). The feedback index may be based on a range of estimated supported rates (denoted by R1), which is determined based on CQI measurements (e.g., as described above). To aid in understanding the example table 800, the column labeled ">=0.75R" is explained. The notation >=0.75R indicates that the estimated supported rate (R1) in the initial transmission is greater than or equal to 0.75R (i.e., 3 / 4 of the actual transmission rate (R)). In such a case, this means that a retransmission of 1 / 3 of the amount of the original data transmission should support an additional rate of 1 / 3*0.75R=0.25R. Thus, when a receiver node combines an initial transmission of 12 CBs together with a retransmission amount of 4 CBs, the overall supported rate is likely to be higher than 1R (i.e., the actual transmission rate), which means that the receiver node is likely to be able to successfully decode the data after the first retransmission. Entries under the column labeled "(0.6R,0.75R)" (i.e., estimated supported rates (R1) greater than 0.6 and less than 0.75 of the actual transmission rate (R)) and under the column labeled "<=0.6R" (i.e., estimated supported rates less than or equal to 0.6 of the actual transmission rate (R)) may be understood similarly. Note that CQI index 0 is reserved to indicate successful decoding (i.e., ACK feedback), in which case retransmission may not be required.

[0111] Additionally, although the exemplary table 800 includes a corresponding proposed retransmission amount (e.g., a proposed number of code blocks or cross block check blocks to use for the retransmission), the transmitter node may not need to explicitly include the proposed retransmission amount in the table 800 since the transmitter node may make its own determination of how the transmission-specific CQI feedback is used to adjust the retransmission parameters. For example, consider that an initial transmission is performed using 1 / 3 rate QPSK, and the initial transmission is a TB with 12 CBs. If the receiver node sends back a feedback index of 2 (which according to the exemplary table 800 corresponds to a proposed retransmission amount of 8 code blocks or cross block check blocks), the transmitter node may perform the retransmission using 8 cross block check blocks and the same rate as the initial transmission (i.e., using 1 / 3 rate QPSK). Alternatively, the transmitter node may choose to perform the retransmission using 12 cross block check blocks, but use a different rate instead (e.g., using 1 / 2 rate QPSK).

[0112] In some examples, the transmission-specific feedback may provide channel coding-related feedback instead of (or in addition to) providing CQI information. The result of channel decoding by the receiver node may provide information about how much additional redundancy is needed in the retransmission to obtain successful decoding (after combining information from the initial transmission and the retransmission).

[0113] FIG. 9 is a flow chart illustrating an example method 900 that may be performed by a receiver node apparatus 200 (eg, a UE 110) to provide channel coding related feedback back to a transmitter node (eg, a BS 170).

[0114] At 902, a transmission of one or more CBs is received from a transmitter node. For example, the transmission may be an initial transmission, and the CB corresponds to a data packet from the transmitter node. The CB may be encoded using a systematic code (e.g., LDPC) or a non-systematic code (e.g., polar code).

[0115] At 904, a decoding operation (also referred to as a decoding attempt) is performed to decode one or more CBs. If the decoding is successful, the receiver node may provide ACK feedback to the transmitter node in lieu of the channel coding related feedback. In other examples, the ACK feedback may be incorporated into the channel coding related feedback (e.g., using a reserved feedback index value) similar to that described above for the transmit specific CQI feedback.

[0116] Assuming that the decoding of at least one CB is not successful, at 906, channel coding related feedback is determined based on the decoding operation. For example, the channel coding related feedback may be determined based on a hard decision decoder output, based on a soft output (e.g., LLR) of the decoder, or based on a decoding convergence behavior. Details of how the channel coding related feedback may be determined are provided further below.

[0117] At 908, the channel coding related feedback is transmitted to the transmitter node. The feedback may be provided together with the ACK / NACK feedback (e.g., on the PUCCH or PUSCH if the transmission is a downlink transmission) or may be provided separately from the ACK / NACK feedback (e.g., on a separate dedicated feedback channel).

[0118] A transmitter node (e.g., BS 170) may use the channel coding related feedback, for example, to determine a retransmission rate. For example, if the transmitter node uses cross block check blocks for retransmissions as described above, the transmitter node may use the channel coding related feedback to determine how many cross block check blocks and / or which RVs to use for retransmissions. However, it should be understood that the transmitter node may use the channel coding related feedback in other ways to adapt retransmissions. In some examples, the transmitter node may perform retransmissions using a conventional HARQ scheme (i.e., without generating cross block check blocks).

[0119] It should be understood that the method 900 may be similarly performed by a receiver node to provide channel coding related feedback in response to a retransmission. For example, if the receiver node is still unable to decode all CBs after a retransmission from the transmitter node, the receiver node may determine and send back additional channel coding related feedback, and the transmitter node may determine how a second retransmission should be performed. The method 900 may be performed, for example, until all of the CBs in the initial transmission are successfully decoded by the receiver node or until a maximum number of retransmissions are performed by the transmitter node.

[0120] 10 is a signaling diagram illustrating an example of channel coding related feedback, for example, by implementing an embodiment of the method 900 in a receiver node. In this example, the transmitter node is the BS 170 and the receiver node is the UE 110 (i.e., downlink transmission), but it should be understood that this is not intended to be limiting. For example, the example of FIG. 10 can be adapted to uplink or sidelink transmission.

[0121] The BS 170 transmits a scheduling 1002 for the initial transmission to the UE 110. For example, the DL scheduling for the initial transmission may be transmitted in a DCI signal. The BS 170 then performs a downlink data transmission 1004 (i.e., an initial transmission including one or more CBs) to the UE 110. The UE 110 receives the transmission and performs a decoding operation to decode the CBs in the initial transmission. In this example, at least one CB is not necessarily decoded, and the UE 110 returns HARQ feedback (e.g., NACK feedback) and channel coding related feedback 1006.

[0122] At 1008, the BS 170 uses the information in the channel coding related feedback to adapt parameters for the retransmission, such as the transmission rate, RV, channel coding method, etc. The BS 170 schedules the retransmission 1010 (e.g., by transmitting another DCI signal) and performs the downlink retransmission 1012. In particular, the retransmission is performed using transmission parameters determined based on the channel coding related feedback from the UE 110. The UE 110 then attempts to decode again using additional information from the retransmission. If the decoding is still unsuccessful, the UE 110 can send back channel coding related feedback again and the BS 170 can perform another retransmission (with adaptation of the transmission parameters according to the channel coding related feedback). This process can be repeated until decoding of all CBs at the UE 110 is successful or until a maximum number of retransmissions is reached. Assuming that all CBs are successfully decoded (after one or more retransmissions), the UE 110 may optionally send HARQ feedback 1014 (eg, ACK feedback) back to the BS 170.

[0123] It should be understood that the various techniques previously described for transmit-specific CQI feedback may also be adapted for use with channel coding related feedback (only differing in that the channel coding related feedback is transmitted instead of the transmit-specific CQI feedback). For example, techniques for quantization of the transmit-specific CQI feedback may be used for quantization of the channel coding related feedback so that fewer bits are required to transmit the channel coding related feedback. In another example, techniques for transmitting transmit-specific CQI feedback together with the ACK / NACK HARQ feedback or in a separate dedicated feedback channel may also be applied to the channel coding related feedback. In another example, various methods in which a transmitter node (e.g., BS 170) uses transmit-specific CQI feedback to adapt retransmission parameters may also be applied in cases in which the transmitter node uses channel coding related feedback to adapt retransmission parameters. Those skilled in the art will readily understand how the aforementioned techniques may be adapted for use with channel coding related feedback, so the details need not be repeated here.

[0124] As mentioned above, the receiver node may determine the channel coding related feedback in a variety of ways, some of which are described herein.

[0125] In one example, the channel coding related feedback may be based on a hard decision decoder output. For example, if the receiver node performs decoding of an LDPC or polar code, the receiver node may use the final decoder output to find the ratio of the number of failed check nodes to the total number of check nodes. Details of the basic encoding and decoding schemes for LDPC codes and polar codes are well known (e.g., LDPC coding is described in Lin et al. Error Control Coding, 2nd edition, Pearson Prentice Hall, Upper Saddle River, 2004) and need not be repeated here. For example, an LDPC code with a parity check matrix denoted H with dimension J×n, where J is the length of the coding bits and n is the length of the information bits, and a LDPC matrix denoted z, where z=(z 1 ,z 2 ,…,z J ) is a row vector representing the binary decision output of the J coded bits. The syndrome of the decoder output may be denoted as s, which is a vector that provides information about the decoding error. Then, s=zH T is the syndrome of the decoder output z, where s=(s 1 ,s,…,s J ), and each s j is one of the J components of s. The number of failed check nodes then equals the number of non-zero components of the syndrome, where J is the total number of components of syndrome s. Thus, the ratio of failed check nodes can be calculated as the ratio of the number of non-zero components of the syndrome divided by J. The ratio of failed check nodes can be quantized (e.g., a defined numeric range may be mapped to a defined number of bits) and sent back as feedback.

[0126] In another example, the final decoder output may be compared with hard decisions on the coded bits from the output signal (after processing, before input to the decoder), and the difference ratio may be quantized and sent back as feedback. In another example, the result of a CRC check of an already decoded CB (or cross block check block, if applicable) may be quantized and sent back as feedback. For example, for an LDPC code transmitted over an additive white Gaussian noise (AWGN) channel, consider a row vector x of length J that is the binary hard decision output of the coded bits based on a received signal sequence that has not passed through a channel decoder of the LDPC code, where the received signal sequence is typically used as the input of the channel decoder. Also consider a row vector z of length J that is the final binary decoded output of the LDPC decoder for the coded bits (as described above). The channel coding related feedback may then be the difference ratio, which may be calculated as the number of non-zero components of the vector (xz) divided by the total number of vector components J.

[0127] In some examples, the channel coding related feedback may be based on the soft output (e.g., LLR) of the decoder. For example, a reliability estimate may be calculated using the output LLR and a quantized estimate may be sent back as feedback.

[0128] In some examples, the channel coding related feedback may be based on the decoding convergence behavior. For example, the number of decoding iterations until convergence (or non-convergence of the decoding operation) may be quantized and provided as feedback. For example, for the output LLR of the information bits of the decoder output, a reliability value may be assigned based on the LLR value. The reliability of all bits of the CB that pass the CRC check may be assigned a reliability value of 1. For the remaining undecoded CBs, the assigned reliability value may be based on a comparison between the absolute value of the LLR and a defined threshold denoted by Th. If the absolute value of the LLR is greater than a given threshold Th, the reliability value may be assigned to be a value of 1. If the LLR is equal to 0, the reliability value may be assigned to be a value of 0. If the absolute value of the LLR is between 0 and Th, the reliability value may be calculated using a defined reliability function (e.g., r=f(LLR)) that assigns a reliability value to be a quantization of the LLR that is in the range between 0 and 1 (the reliability function may be defined such that the greater the absolute value of the LLR, the greater the reliability value (but always less than 1)). The overall reliability to be transmitted as channel coding related feedback can then be estimated as the sum of all reliability values ​​of all information bits divided by the total number of information bits. The reliability function and / or threshold Th can be defined empirically (e.g., from experimental data and calculated or based on the output of multiple iterations / convergence behavior).

[0129] In examples where quantization is used, the quantization values ​​may be index values ​​that are mapped to defined numerical ranges given in tables defined in the standard (e.g., similar to how CQI index values ​​are mapped using defined CQI tables).

[0130] It should be noted that the channel coding related feedback may be used to help the transmitter node determine various retransmission parameters, such as retransmission rate, channel coding scheme, RV index, or other parameters. For example, the transmitter node may use the channel coding related feedback to help determine which coded bits to use for the retransmission (e.g., which RV index to use for the retransmission). In one example, if the channel coding related feedback indicates poor decoding results in the initial transmission (e.g., indicates that most of the CBs could not be decoded), the transmitter node may determine that the retransmission should be performed with RV index 0 (i.e., the same as the initial transmission, where RV index 0 typically contains more information bits than other RV indexes). On the other hand, if the channel coding related feedback indicates good decoding results (e.g., successful decoding of most, but not all, of the CBs in the initial transmission), the transmitter node may determine that the retransmission should be performed with RV index 1 or 2 instead, which contains fewer information bits and can provide incremental redundancy.

[0131] 11 is a flow chart illustrating an example method 1100 that may be performed by the apparatus 200, which is a transmitter node (e.g., BS 170). The method 1100 may be performed in a situation where transmission-specific CQI feedback or channel coding related feedback is sent back by a receiver node (e.g., UE 110). For example, the method 1100 may be performed by BS 170 in the examples of FIG. 6 or FIG. 10.

[0132] At 1102, the transmitter node transmits one or more CB transmissions to the receiver node. For example, the transmission may be an initial transmission, where the CB corresponds to a data packet. The transmission includes a reference signal, for example, a DMRS.

[0133] At 1104, transmission-specific CQI feedback or channel coding related feedback is received from the receiver node, e.g., as described above. The feedback may be received as ACK / NACK feedback (e.g., on the PUCCH or PUSCH) or may be provided separately from the ACK / NACK feedback (e.g., on a separate feedback channel). If ACK feedback is received, method 1100 may end. If the feedback indicates that a retransmission is required, method 1100 proceeds to step 1106.

[0134] At 1106, the transmitter node uses the feedback (e.g., transmission-specific CQI feedback or channel coding-related feedback) to determine parameters for performing the retransmission. For example, the transmitter node may determine a code rate, a number of cross block check blocks (if cross block check blocks are used), an MCS, a power level, beamforming, etc., to use for the retransmission. If the feedback indicates a recommended or proposed retransmission rate, for example, the transmitter node may use the recommended or proposed retransmission rate for the retransmission. In some examples, the transmitter node may choose to ignore the recommended or proposed retransmission rate and determine its own retransmission parameters.

[0135] At 1108, a retransmission is sent to the receiver node using the parameters determined in step 1106. The transmitter node may perform the retransmission using a set of one or more cross block check blocks, as described above. In another example, the transmitter node may perform the retransmission using a conventional HARQ scheme (i.e., without generating a cross block check block).

[0136] It should be appreciated that steps 1104-1108 may be repeated to perform multiple retransmissions. For example, the transmitter node may continue to receive feedback from the receiver node and perform retransmissions using parameters determined based on the feedback until all of the CBs in the initial transmission are successfully decoded by the receiver node (e.g., until an ACK is received from the receiver node) or until a maximum number of retransmissions have been performed by the transmitter node.

[0137] Although examples have been described in the context of unicast transmission (i.e., a transmitter node transmits to one receiver node), it should be understood that the present disclosure may also be used in groupcast or multicast applications. For example, in a groupcast or multicast transmission, each receiver node may determine and send back its own transmit-specific CQI feedback (or channel coding related feedback). The transmitter node may use the worst-case feedback (i.e., the transmit-specific CQI feedback (or channel coding related feedback) that indicates the worst channel quality (or most unsuccessful decoding attempts) among all receiver nodes) as a basis for determining parameters for retransmission.

[0138] In various examples, this disclosure has described feedback schemes that provide transmission-specific (also called dynamic or instantaneous) feedback. In particular, transmission-specific CQI feedback and channel coding related feedback have been described. Examples of this disclosure may enable a transmitter node (e.g., BS) to determine retransmission parameters (e.g., retransmission rate, MCS, power level, beamforming, etc.). The disclosed feedback may be used in retransmission schemes that utilize cross block check blocks as well as retransmission schemes that do not utilize cross block check blocks.

[0139] This disclosure describes example methods of quantization of transmission-specific CQI feedback and channel coding-related feedback, which help reduce associated overhead. In some examples, index-based feedback (e.g., using existing CQI tables) may be adapted for use with the disclosed feedback schemes.

[0140] Although this disclosure describes methods and processes with a particular order of steps, one or more steps of the methods and processes may be omitted or modified, if desired. One or more steps may be performed in an order other than the order described, if desired.

[0141] Although the present disclosure is described at least in part with respect to a method, those skilled in the art will understand that the present disclosure is also directed to various components for performing at least some of the aspects and features of the described method, by hardware components, software, or any combination of the two. Thus, the technical solutions of the present disclosure may be embodied in the form of a software product. A suitable software product may be stored in a pre-recorded storage device or other similar non-volatile or non-transitory computer-readable medium, including, for example, a DVD, a CD-ROM, a USB flash disk, a removable hard disk, or other storage medium. The software product includes tangibly stored instructions that enable a processing device (e.g., a personal computer, a server, or a network device) to execute the method examples disclosed herein. The machine-executable instructions may be in the form of code sequences, configuration information, or other data that, when executed, cause a machine (e.g., a processor or other processing device) to perform steps of a method according to the examples of the present disclosure.

[0142] The present disclosure may be embodied in other specific forms without departing from the subject matter of the claims. The described exemplary embodiments should be considered in all respects as illustrative only and not limiting. Selected features from one or more of the above embodiments may be combined to form alternative embodiments not expressly described, and features suitable for such combinations are understood to be within the scope of the present disclosure.

[0143] All values ​​and subranges within the disclosed ranges are also disclosed. Also, while the systems, devices, and processes disclosed and illustrated herein may include a particular number of elements / components, the systems, devices, and assemblies can be modified to include additional or fewer such elements / components. For example, although any of the disclosed elements / components may be referred to in the singular, the embodiments disclosed herein may be modified to include a plurality of such elements / components. The subject matter described herein is intended to cover and encompass any appropriate changes in technology. [Explanation of symbols]

[0144] 15 New Radio (NR) Release 100 Radio System 110 User Equipment (UE) 120 Radio Access Network (RAN) 130 Core Network 140 Public Switched Telephone Network (PSTN) 150 Internet 160 other networks 170 Base Station (BS) 190 Uplink (UL) / Downlink (DL) Air Interface 195 Sidelink (SL) Radio Interface 200 equipment 201 Processing Unit 202 Communication Interface 204 Antenna 206 Input / Output Devices 208 Memory 302,304 packets 304 Information Block 306 Horizontal Check Block 308 Cross Block Check Block 310 Code Block (CB) 312 Non-systematic codewords 402,422 Radio Resource Control (RRC) Signaling 404 Activation Signal 406,426 CSI-RS 408,428 CSI Report 410 Disable Signal 424 UL Scheduling Permit 602,1002 Scheduling 604,1004 Downlink data transmission 606 HARQ Feedback and Transmit-Specific CQI Feedback 610,1010 retransmission 612 DMRS 614,1014 HARQ Feedback 700 CQI Table 800 tables 1006 HARQ feedback and channel coding related feedback 1012 Downlink retransmission

Claims

1. A method in a receiver node, comprising: receiving a data transmission from a transmitter node, the data transmission including a transmission of an associated reference signal; determining a transmission-specific channel quality indicator (CQI) associated with the received data transmission from the reference signal; transmitting feedback to the transmitter node indicative of the transmit specific CQI; A method comprising:

2. The method of claim 1 , wherein the reference signal is a demodulation reference signal (DMRS).

3. the data transmission includes one or more code blocks, the method further including performing a decoding operation to decode the one or more code blocks; The method comprises: in response to successful decoding of the one or more code blocks, the feedback indicative of the transmit-specific CQI represents an acknowledgement (ACK) indicating successful decoding; or In response to unsuccessful decoding of at least one of the one or more code blocks, the feedback indicative of the transmission-specific CQI represents a negative acknowledgement (NACK) indicating unsuccessful decoding or The method of claim 1 or 2, further comprising one of:

4. The method of claim 1 or 2, wherein the feedback indicative of the transmission-specific CQI is sent separately from a response feedback.

5. 5. The method of claim 1, wherein the transmission-specific CQI indicates the highest supported modulation and coding scheme (MCS) that can be supported by a current channel quality measured from the reference signal and that provides a block error rate (BLER) below a defined threshold.

6. The transmission specific CQI is 6. The method of claim 5, wherein the CQI index value is determined by identifying, from a defined CQI table, a CQI index value that corresponds to a highest supported MCS, and the identified CQI index value is used as the transmission-specific CQI.

7. The method of claim 6 , wherein a reserved CQI index value in the defined CQI table is defined to indicate an ACK.

8. The step of determining a transmit specific CQI comprises: determining a differential CQI representing a difference in channel quality between a current channel quality measured from the reference signal of the received data transmission and a previously reported channel quality, the differential CQI being used as the transmission-specific CQI; 5. The method according to claim 1 , comprising:

9. 9. The method of claim 8, wherein the differential CQI is indicated as a difference between a first MCS used for the received data transmission based on the previously reported channel quality and a second MCS that is the highest supported MCS that can be supported by the current channel quality.

10. 10. The method of claim 1, wherein the data transmission is a retransmission that includes one or more retransmitted code blocks or one or more cross block check blocks generated from selected bits across one or more code blocks of the data transmission.

11. receiving a retransmission from the transmitter node after transmitting the feedback, the retransmission using at least one retransmission parameter that differs from a corresponding parameter used for the data transmission; 11. The method of any one of claims 1 to 10, further comprising:

12. A method in a transmitter node, comprising: transmitting a data transmission to a receiver node, the data transmission including a transmission of one or more code blocks and associated reference signals; receiving feedback from the receiver node indicative of a transmission-specific channel quality indicator (CQI) associated with the received data transmission; sending a retransmission to the receiver node using retransmission parameters determined based on the received feedback; A method comprising:

13. The method of claim 12 , wherein the reference signal is a demodulation reference signal (DMRS).

14. The method of claim 12 or 13, wherein the feedback indicative of the transmit-specific CQI represents a negative acknowledgement (NACK), indicating unsuccessful decoding of the one or more code blocks at the receiver node.

15. The method of claim 12 or 13, wherein the feedback indicative of the transmission specific CQI is transmitted separately from a NACK feedback.

16. determining at least one retransmission parameter, the at least one retransmission parameter comprising: Retransmission rate, Modulation and Coding Scheme (MCS), Power level, Beamforming parameters, The number of code blocks that were retransmitted, or Number of check blocks The method according to any one of claims 12 to 15, further comprising the step of:

17. 17. The method of claim 12, wherein the transmission-specific CQI corresponds to a proposed retransmission rate, and the retransmission is performed using the proposed retransmission rate.

18. 18. The method of claim 12, wherein the retransmission includes one or more retransmitted code blocks or one or more cross block check blocks generated from selected bits across the one or more code blocks of the data transmission.

19. A method in a receiver node, comprising: receiving a data transmission of one or more code blocks from a transmitter node; performing a decoding operation to decode the one or more code blocks; determining channel coding related feedback based on the decoding operation; transmitting said channel coding related feedback to said transmitter node; A method comprising:

20. 20. The method of claim 19, wherein the channel coding related feedback is determined based on a hard decision output from a decoder at the receiver node generated from the decoding operation.

21. 20. The method of claim 19, wherein the channel coding related feedback is determined based on a soft output from a decoder at the receiver node generated from the decoding operation.

22. 20. The method of claim 19, wherein the channel coding related feedback is determined based on a decoding convergence behavior of a decoder at the receiver node during the decoding operation.

23. An apparatus comprising: A processing unit; a non-transitory memory containing instructions that, when executed by the processing unit, cause the apparatus to perform the method of any one of claims 1 to 22; An apparatus comprising:

24. A non-transitory computer readable medium having machine executable instructions stored thereon, the instructions, when executed by a processing unit of an apparatus, causing the apparatus to perform a method according to any one of claims 1 to 22.

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