Codeword bit interleaving scheme for multi-layer transmission in wireless communication systems

Abstract

This invention relates to a codeword bit interleaving scheme for multi-layer transmission in a wireless communication system. The codeword bit interleaving scheme involves dividing the columns of an interleaving matrix into at least two separate column groups based on the transmission quality (e.g., SNR) of the data transmission layer (e.g., MIMO layer). Then, starting with writing information bits into the column group corresponding to the high-quality data transmission layer, the column group is filled with codeword bits. Afterwards, all column groups are merged to restore the initial column arrangement of the interleaving matrix, and codeword bits are read row by row from the interleaving matrix and mapped to modulation symbols. The modulation symbols are then mapped to the data transmission layer itself. By doing so, the information bits of the codewords can be allocated to the high-quality data transmission layer, thereby improving decoding performance.

Description

Technical Field

[0001] This invention relates generally to the field of wireless communication, and particularly to a codeword bit interleaving scheme for multilayer transmission in wireless communication systems. Background Technology

[0002] Fifth-generation (5G) mobile wireless communication networks, such as the 3rd Generation Partnership Project (3GPP) New Radio (NR), use a multiple-input multiple-output (MIMO) approach to achieve very high data rates between base stations (BS) or gNodeBs (gNBs) and user equipment (UEs). The MIMO method employs multipath propagation over the radio channel by using multiple transmitter and receiver antennas to create multiple spatial layers (also known as MIMO layers) capable of transmitting information concurrently. Propagation phenomena occurring over the radio channel often lead to large imbalances in the signal-to-noise ratio (SNR) between MIMO layers. If these large SNR imbalances are not properly handled, they can cause performance degradation.

[0003] In NR, any data stream exchanged between the gNB and the UE consists of a series of data blocks. Each data block is independently encoded into a codeword using error-correcting codes. NR relies on low-density parity-check (LDPC) codes for error correction. The codeword bits are then interleaved and modulated to transmit them to the gNB or UE through the MIMO layer.

[0004] However, despite the potential for large SNR imbalances in MIMO layers, NR still uses the same modulation and code rate across all MIMO layers. To guarantee a given transmission reliability, modulation / code rate selection is based on the transmission quality specific to the worst (i.e., low SNR) MIMO layer. This makes it impossible to fully utilize the transmission quality of high SNR MIMO layers, resulting in bit rate limitations. Summary of the Invention

[0005] This summary is provided to introduce some concepts in a simplified form, which will be further described below in the detailed description. This summary is not intended to identify key features of the invention, nor is it intended to limit the scope of the invention.

[0006] The purpose of this invention is to provide a technical solution for implementing codeword bit interleaving in multilayer transmission in wireless communication systems.

[0007] The above-described objectives are achieved through the features of embodiments of the present invention. Other embodiments and examples will become apparent from the content, detailed description, and accompanying drawings of the present invention.

[0008] According to a first aspect, an apparatus for a wireless communication system is provided. The apparatus includes a processor, a memory coupled to the processor, and a transceiver. The memory stores processor-executable instructions. When executed, the processor causes the processor to operate as follows: First, the processor receives codewords to be transmitted through data transmission layers. Each data transmission layer has a transmission quality, and the codewords are obtained using linear codes. The codewords have a codeword length E and include codeword bits. The codeword bits include at least one information bit and at least one parity bit. Then, the processor performs interleaving of the codeword bits using a matrix having n rows and k columns, where n and k are selected based on a predefined modulation scheme and the codeword length E. Each column corresponds to a data transmission layer. The interleaving operation includes:

[0009] - Arrange the columns corresponding to data transmission layers with transmission quality equal to or higher than the threshold into at least one first column group;

[0010] - Arrange the columns corresponding to data transmission layers with transmission quality below a threshold into at least one second column group;

[0011] - Begin by writing at least one information bit line by line into the at least one first column group, and then write codeword bits line by line into the at least one first column group and the at least one second column group;

[0012] - Combine the at least one first column group and the at least one second column group to recover the matrix; and

[0013] - Read codeword bits column by column from the matrix.

[0014] Once the interleaving operation is complete, the processor uses a predefined modulation scheme to obtain the modulation symbols for the codeword bits read from each column of the matrix. The processor then maps the modulation symbols to the data transmission layer. Next, the transceiver transmits the mapped modulation symbols to the target device in the wireless communication system.

[0015] By performing interleaving in this manner, even if codewords are transmitted over multiple data transmission layers with significantly different transmission qualities, the apparatus according to the first aspect can map the information bits of the codewords to a data transmission layer with high transmission quality (e.g., high SNR). Furthermore, this mapping can improve decoding performance in the target apparatus, thereby achieving a lower error rate and higher spectral efficiency.

[0016] In one embodiment of the first aspect, the predefined modulation scheme has a modulation order Q. m And n is equal to the modulation order Q m Meanwhile, k is determined by applying a floor or ceiling function to the codeword length E and the modulation order Q. m This is obtained by comparing the ratios. By doing so, a more efficient interleaving matrix can be created, thereby improving the efficiency of the entire interleaving operation.

[0017] In one embodiment of the first aspect, the processor is further configured to: determine the modulation order Q of a predefined modulation scheme based on the transmission quality of the data transmission layer prior to the interleaving operation. m By doing so, a modulation order Q that is more suitable for a given data transmission layer can be selected. m This improves the efficiency of the entire interleaving operation.

[0018] In one embodiment of the first aspect, the Q-value of the codeword bits in each column of the predefined modulation scheme definition matrix is... m The mapping from tuples to modulation symbols, and the processor is also used for:

[0019] - Determine each Q based on the transmission quality of the data transmission layer. m The bit capacity of the codeword bits in a tuple; and

[0020] - Based on the determined bit capacity, determine: (i) the number G of columns of matrix (800) to which the at least one first column group (802) and the at least one second column group (804) will be arranged, and (ii) the correspondence between each data transmission layer in the data transmission layer and the at least one first column group (802) or the at least one second column group (804).

[0021] By doing so, the efficiency of grouping the columns of the matrix used in the interleaving operation can be improved, thereby improving the efficiency of the entire interleaving operation.

[0022] In one embodiment of the first aspect, the processor is further configured to: generate a control message before the transceiver transmits the mapped modulation symbol to the target device, and cause the transceiver to transmit the control message to the target device. The control message may include at least one of the following: modulation order Q.m The codeword length E; the number G of at least one first column group and at least one second column group used in interleaving codeword bits; and the correspondence between each data transmission layer and the at least one first column group or the at least one second column group. By doing so, information about the codeword bit interleaving scheme used by the apparatus according to the first aspect can be provided to the target device, thereby enabling the target device to perform deinterleaving and thus perform decoding operations more efficiently and faster.

[0023] In one embodiment of the first aspect, the codeword is obtained using a linear code selected from turbo codes, system codes, system polar codes, and LDPC codes. This allows for greater flexibility in the use of the apparatus according to the first aspect, since, for example, LDPC codes can be used for 5G NR.

[0024] In one embodiment of the first aspect, the predefined modulation scheme includes one of quadrature amplitude modulation (QAM), phase shift keying (PSK), and quadrature PSK (QPSK). This allows for greater flexibility in the use of the apparatus according to the first aspect, as the apparatus can select from the modulation schemes depending on the specific application.

[0025] In one embodiment of the first aspect, the processor is further configured to: predetermine the transmission quality of the data transmission layer based on an uplink reference signal in the case of time-division duplex (TDD) communication, or based on a downlink reference signal in the case of frequency-division duplex (FDD) communication. This allows the apparatus according to the first aspect to be used more flexibly, as it can be adapted to different duplex communication links.

[0026] In one embodiment of the first aspect, the data transmission layer includes a MIMO spatial layer. This enables the apparatus according to the first aspect to be used in MIMO wireless communication systems, thereby increasing its flexibility of use.

[0027] According to a second aspect, a method for wireless communication is provided. The method begins with receiving a codeword to be transmitted through a data transmission layer. Each data transmission layer has a transmission quality, and the codeword is obtained using a linear code. The codeword has a codeword length E and includes codeword bits. The codeword bits include at least one information bit and at least one parity bit. The method then performs a step of interleaving the codeword bits using a matrix with n rows and k columns, where n and k are chosen based on a predefined modulation scheme and the codeword length E. Each column corresponds to a data transmission layer. The interleaving step includes the following sub-steps:

[0028] - Arrange the columns corresponding to data transmission layers with transmission quality equal to or higher than the threshold into at least one first column group;

[0029] - Arrange the columns corresponding to data transmission layers with transmission quality below a threshold into at least one second column group;

[0030] - Begin by writing at least one information bit line by line into the at least one first column group, and then write codeword bits line by line into the at least one first column group and the at least one second column group;

[0031] - Combine the at least one first column group and the at least one second column group to recover the matrix; and

[0032] - Read codeword bits column by column from the matrix.

[0033] When the interleaving step ends, the method proceeds to obtain modulation symbols of codeword bits read from each column of the matrix using a predefined modulation scheme. Then, the method initiates the next step, in which the modulation symbols are mapped to the data transmission layer. Next, the method transmits the mapped modulation symbols to the target wireless communication device.

[0034] By performing the interleaving step in this manner, even if the codeword is transmitted over multiple data transmission layers with significantly different transmission qualities, the information bits of the codeword can be mapped to a data transmission layer with high transmission quality (e.g., high SNR). Furthermore, this mapping can improve the decoding performance in the target wireless communication device, thereby achieving a lower error rate and greater spectral efficiency.

[0035] In one embodiment of the second aspect, the predefined modulation scheme has a modulation order Q. m And n is equal to the modulation order Q m Meanwhile, k is determined by applying a floor function to the codeword length and modulation order Q. m This is obtained by comparing the ratios. By doing so, a more efficient interleaving matrix can be created, thereby improving the efficiency of the entire interleaving process.

[0036] In one embodiment of the second aspect, the method further includes determining the modulation order Q of a predefined modulation scheme based on the transmission quality of the data transmission layer prior to the interleaving step. m This is the step. By doing so, a modulation order Q that is more suitable for a given data transmission layer can be selected. m This improves the efficiency of the entire interlacing process.

[0037] In one embodiment of the second aspect, the Q-value of the codeword bits in each column of the predefined modulation scheme definition matrix is... m Mapping tuples to modulation symbols. In this embodiment, the method further includes the following steps:

[0038] - Determine each Q based on the transmission quality of the data transmission layer. m The bit capacity of the codeword bits in a tuple; and

[0039] - Based on the determined bit capacity, determine: (i) the number G of columns of matrix (800) to which the at least one first column group (802) and the at least one second column group (804) will be arranged, and (ii) the correspondence between each data transmission layer in the data transmission layer and the at least one first column group (802) or the at least one second column group (804).

[0040] By doing so, the efficiency of grouping the columns of the matrix used in the interleaving step can be improved, thereby improving the efficiency of the entire interleaving step.

[0041] In one embodiment of the second aspect, prior to the transmission step, the method further includes the step of generating a control message and transmitting the control message to a target wireless communication device. The control message may include at least one of the following: modulation order Q. m The codeword length E; the number G of at least one first column group and at least one second column group used when interleaving codeword bits; and the correspondence between each data transmission layer and at least one first column group or at least one second column group. By doing so, information about the codeword bit interleaving scheme used in the method according to the second aspect can be provided to the target wireless communication device on the transmitting side, thereby enabling the target wireless communication device to perform deinterleaving and thus decode the codeword bits more efficiently and faster.

[0042] In one embodiment of the second aspect, the codeword is obtained using a linear code selected from turbo codes, system codes, system polar codes, and LDPC codes. This allows for greater flexibility in the application of the method according to the second aspect, as LDPC codes can be used, for example, in 5G NR.

[0043] In one embodiment of the second aspect, the predefined modulation scheme includes one of a QAM scheme, a PSK modulation scheme, and a QPSK modulation scheme. This allows for greater flexibility in using the method according to the second aspect, as it provides the possibility of selecting the modulation scheme based on a specific application.

[0044] In one embodiment of the second aspect, the method further includes the step of pre-determining the transmission quality of the data transmission layer based on an uplink reference signal in the case of time-division duplex (TDD) communication, or based on a downlink reference signal in the case of frequency-division duplex (FDD) communication. This allows for greater flexibility in the use of the method according to the second aspect, as it can be applied to different duplex communication links.

[0045] In one embodiment of the second aspect, the data transmission layer includes a MIMO spatial layer. This allows the method according to the second aspect to be used in MIMO wireless communication systems, thereby increasing its flexibility of use.

[0046] According to a third aspect, a computer program product is provided. The computer program product includes a computer-readable storage medium storing computer code. When executed by at least one processor, the computer code causes the at least one processor to perform the method according to the second aspect. By using such a computer program product, the implementation of the method according to the second aspect in any computing device, such as the apparatus according to the first aspect, can be simplified.

[0047] Other features and advantages of the invention will become apparent after reading the following detailed description and reviewing the accompanying drawings. Attached Figure Description

[0048] The invention will now be described in conjunction with the accompanying drawings, in which:

[0049] Figure 1 A block diagram of a conventional transmitter for performing NR LDPC encoded transmission is shown;

[0050] Figure 2 It shows the result of Figure 1 The example structure shown is that of the first codeword segment of the initial transmission performed by a conventional transmitter;

[0051] Figure 3 This explains that in Figure 1 The interleaving, modulation, and layer mapping operations performed in the conventional transmitter shown;

[0052] Figure 4 Showing the target Figure 1The bit capacity of the different modulation schemes used in the conventional transmitters shown. and (Assuming a dependence on the unit average modulation symbol energy);

[0053] Figure 5 A block diagram of a wireless communication device according to an exemplary embodiment is shown;

[0054] Figure 6 An exemplary embodiment is shown in Figure 5 A block diagram of the processor used in the device shown;

[0055] Figure 7 A flowchart of a wireless communication method according to an exemplary embodiment is shown;

[0056] Figure 8 This explains the situation when using two column groups. Figure 7 The method shown includes the interleaving step, modulation step, and mapping step;

[0057] Figure 9 This demonstrates the application of 16QAM(Q m Dependencies of numerical examples of (=4)

[0058] Figure 10 It shows that they are respectively made by Figure 1 The conventional interleaver in the conventional transmitter shown Figure 6 The matrix used by the interleaver in the processor shown, and the corresponding bit capacity for the first transmission in the numerical example;

[0059] Figure 11 It shows that they are respectively made by Figure 1 The conventional interleaver in the conventional transmitter shown Figure 6 The matrix used by the interleaver in the processor shown, and the corresponding bit capacity for the second transmission in the numerical example;

[0060] Figure 12 The relationship between block error rate (BLER) and SNR is shown for two transmissions in a numerical example.

[0061] Figure 13A and Figure 13B The BLER performance of LDPC-coded transmission with QPSK modulation and 16QAM modulation is shown for v=2 MIMO layers and G=2 column groups;

[0062] Figure 14A and Figure 14B It shows the target and Figure 13A and Figure 13BThe code rate and modulation used are the same as the code rate and modulation metric Δ. CC Dependence on SNR; and

[0063] Figure 15A and Figure 15B The BLER performance of LDPC-coded transmissions with QPSK modulation and 16QAM modulation is shown for different layer SNR differences. Detailed Implementation

[0064] Various embodiments of the invention are described in further detail with reference to the accompanying drawings. However, the invention may be embodied in many other forms and should not be construed as limited to any particular structure or function discussed in the following description. Rather, these embodiments are provided to make the description of the invention detailed and complete.

[0065] As will be apparent to those skilled in the art from the specific embodiments described herein, the scope of the invention covers any of the embodiments disclosed herein, whether implemented independently or in conjunction with any other embodiments of the invention. For example, the apparatuses and methods disclosed herein can be implemented in practice using any number of the embodiments provided herein. Furthermore, it should be understood that any embodiment of the invention can be implemented using one or more elements set forth in the appended claims.

[0066] The term “exemplary” means “used for illustration” in this document. Unless otherwise stated, any embodiment described herein as “exemplary” should not be construed as preferred or having an advantage over other embodiments.

[0067] According to the exemplary embodiments disclosed herein, a user equipment, or UE for short, may refer to a mobile device, mobile station, terminal, user device, mobile phone, cellular phone, smartphone, cordless phone, personal digital assistant (PDA), wireless communication device, desktop computer, laptop computer, tablet computer, gaming device, netbook, smartbook, ultrabook, medical device or medical equipment, biometric sensor, wearable device (e.g., smartwatch, smart glasses, smart wristband, etc.), entertainment device (e.g., audio player, video player, etc.), vehicle component or sensor, smart meter / sensor, unmanned vehicle (e.g., industrial robot, quadcopter, etc.), industrial manufacturing equipment, global positioning system (GPS) device, internet-of-thing (IoT) device, industrial IoT (IIoT) device, machine-type communication (MTC) device, massive IoT (MIoT) or massive MTC (mMTC) device / sensor group, or any other suitable device for supporting wireless communication. In some embodiments, a UE may refer to at least two UEs that are placed side by side and interconnected, as defined in this way.

[0068] As used in the exemplary embodiments disclosed herein, a Radio Access Network node (or RAN node for short) may refer to a fixed communication point of a UE in a specific wireless communication network. An RAN node may be referred to as a base transceiver station (BTS) in 2G communication technology, as a NodeB in 3G communication technology, as an evolved NodeB (eNodeB) in 4G communication technology, and as a gNB in ​​5G new radio (NR) communication technology. RAN nodes may serve different types of cells, such as macrocells, microcells, picocells, femtocells, and / or other cell types. A macrocell may cover a relatively large geographic area (e.g., a radius of at least several kilometers). A microcell may cover a geographic area, for example, with a radius of less than two kilometers. A picocell may cover a relatively small geographic area, such as an office, shopping mall, train station, stock exchange, etc. A femtocell may cover an even smaller geographic area (e.g., a home). Accordingly, an RAN node serving a macrocell may be referred to as a macro node, an RAN node serving a microcell may be referred to as a micro node, and so on.

[0069] According to the exemplary embodiments disclosed herein, the wireless communication network in which the UE and RAN nodes communicate with each other can refer to a cellular or mobile telecommunications network, a wireless local area network (WLAN), a wireless personal area network (WPAN), a wireless wide area network (WWAN), a satellite communication (SATCOM) system, or any other type of wireless communication network. Each of these types of wireless communication networks supports wireless communication according to one or more communication protocol standards. For example, cellular networks can operate according to the Global System for Mobile Communication (GSM), Code-Division Multiple Access (CDMA), Wide-Band Code-Division Multiple Access (WCDM), Time-Division Multiple Access (TDMA), or any other communication protocol standard; WLANs can operate according to one or more versions of the IEEE 802.11 standard; WPANs can operate according to the Infrared Data Association (IrDA), Wireless USB, Bluetooth, or ZigBee standards; and WWANs can operate according to the Worldwide Interoperability for Microwave Access (WiMAX) standard.

[0070] As used in the exemplary embodiments disclosed herein, a wireless communication system can refer to a set of at least two entities (e.g., a UE and a RAN node, two UEs, two RAN nodes, etc.) that communicate with each other over any wireless communication network (similar to the wireless communication network described above). This communication can be performed, for example, through a radio channel established between a UE and a gNB. To achieve very high data rates, MIMO methods can be applied to the radio channel. MIMO methods involve using multiple transmit antennas and multiple receive antennas (i.e., MIMO channels) for data transmission. A MIMO channel formed by multiple transmit and receive antennas can be decomposed into independent channels. Each independent channel can also be referred to as a spatial subchannel or spatial or MIMO layer of the MIMO channel. MIMO methods make it possible to perform spatial multiplexing or spatial diversity. Spatial multiplexing refers to the simultaneous transmission of multiple data streams through multiple spatial layers of a MIMO channel.

[0071] Propagation phenomena occurring on radio channels typically lead to large imbalances in the signal-to-noise ratio (SNR) between MIMO layers. Large SNR imbalances can cause performance degradation. Table 1, given below, shows examples of MIMO layer SNRs for different numbers of NR physical downlink shared channel (PDSCH) transmissions. It is assumed that each PDSCH transmission has a different number of MIMO layers available. The number of MIMO layers depends on the radio channel. In Table 1, cells without any numbers indicate that the associated MIMO layer is unavailable in the corresponding PDSCH transmission. In NR, only one channel quality (e.g., SNR) is reported for multiple MIMO layers, and only one modulation and code rate are used for transmission on the MIMO layers. Therefore, the transmission performance of the entire MIMO channel is limited by the lowest quality in the MIMO layers (e.g., for the initial transmission in the example given in Table 1, the lowest quality is 8.6 dB, representing the SNR of layer 4).

[0072] Table 1. Examples of SNR in MIMO layer during MIMO transmission.

[0073]

[0074]

[0075] Figure 1 A block diagram of a conventional transmitter 100 for performing NR LDPC encoded transmission is shown. Transmitter 100 may be part of a wireless communication device, such as a UE or gNB. Figure 1As shown, transmitter 100 includes an LDPC encoder 102, a cyclic buffer 104, an interleaver 106, a modulator 108, and a layer mapper 110, which are used in transmitter 100 in the order mentioned. It is important to note that in NR, any data stream exchanged between, for example, a gNB and a UE consists of a series of data blocks. These data blocks are processed independently of each other by transmitter 100. More specifically, as... Figure 1 As shown, each data block is independently encoded by LDPC encoder 102 using error correction code (i.e., LDPC code in this case), interleaved by interleaver 106, modulated by modulator 108, and mapped to v MIMO layers by layer mapper 110.

[0076] Now let's consider the operation of transmitter 100 in more detail.

[0077] LDPC encoder 102 will convert data block i = (i1,…,i K Mapped to codeword c = (c1, ..., c) N The codeword c is written into the circular buffer 104 in the transmitter 100. In the initial transmission, the first codeword segment c0 = (c e The first codeword segment, e = 1, ..., E (E > K), is read from the circular buffer 104 and sent to the interleaver 106, where it undergoes bit interleaving, or in other words, bit rearrangement or swapping. Therefore, the initial transmission has an initial value equal to R. C =K / E error correction code rate.

[0078] Figure 2 An exemplary structure 200 of the first codeword segment c0 of the initial transmission performed by transmitter 100 is shown. Figure 2 As shown, the first codeword segment c0 consists of two main parts: a first part 202 containing information bits (commonly referred to as system bits) and a second part 204 containing parity bits (also called parity check bits). The first codeword segment c0 can optionally be obtained by removing or puncturing some information bits to accelerate the convergence of the LDPC decoder. Such removed or punctured bits are... Figure 2 The first codeword segment c0 is represented as "206". Typically, the first codeword segment c0 can be written as:

[0079] c0 = (c1, c2, ..., c E )=(j1,j2,…,j K-2Z ,p1,…,p E-K+2Z ),

[0080] Where j1 = i 2Z+1 j2=i 2Z+2 ,…,j K-2Z=i K These are information bits, and p1,…,p E-K+2Z These are parity bits. The initial 2Z information bits (where Z represents the boosting factor used to boost the parity check matrix of a given LDPC code) are truncated, meaning that the truncated bits are neither written to the circular buffer 104 nor transmitted by the transmitter 100.

[0081] Figure 3 This describes the interleaving, modulation, and layer mapping operations performed in transmitter 100. For example... Figure 3 As shown, the interleaver 106 uses a rectangular array or matrix 300 (also known as an interleaving matrix) with the number of rows equal to the modulation order Q of the preselected modulation scheme. m And the number of columns S = E / Q m The bits of c0 are written into matrix 300 row by row, starting from the top row and proceeding from left to right. Since the initial portion of c0 contains (K-2Z) information bits, therefore... The top row is filled with information bits. The remaining information bits (if any) are written to the first row. Okay. The rest of matrix 300 is filled with odd and even bits.

[0082] Once all the bits of c0 have been written into matrix 300, these bits are read from matrix 300 column by column from top to bottom, starting from the leftmost column, thus producing the output b = (b1,…,b) of interleaver 106. E Therefore, the nth output bit of interleaver 106 is Here, mod represents the modulo operation. The s-th column (where s = 1, ..., S) of interleaver 106 produces the Q bits. m tuple The tuple is then mapped to the complex modulation symbol d. s Therefore, any Q m The initial bits of a tuple are all information bits. Assume Q... m The bits in the tuple do not increase the reliability level, which allows the information bits to be mapped to a high-capacity bit channel. Each bit channel can be considered as a physical resource used to pass codeword bits to the receiver by mapping codeword bits to modulation symbols. Therefore, the modulator 108 generates a modulation symbol vector d = (d1, ..., d...). S ), its in Figure 3 The value in the middle is represented as 302.

[0083] Layer mapper 110 maps modulation symbols 302 from d to v MIMO layers 304, where 1 ≤ v ≤ 4. More specifically, layer mapper 110 forms v modulation symbol vectors—one modulation symbol vector for each MIMO layer, where the l-th vector can be written as d l=(d l ,d l+v ,d l+2v ,…), l=1,…,v. It is important to note that columns in matrix 300 associated with the same MIMO layer are filled using the same dotted pattern. Figure 3 As shown (e.g., the column with the densest dot pattern filling corresponds to MIMO layer 1). In another step ( Figure 3 (Not shown in the image), the layer-mapped symbols are pre-coded and mapped to time-frequency resource elements, then modulated, for example, by using orthogonal frequency division multiplexing (OFDM), and transmitted to a receiver, for example, another UE or gNB.

[0084] For the remaining (overlapping and / or non-overlapping) codeword segments of codeword c, the transmission process described above for the first codeword segment c0 is repeated segment by segment. More specifically, each subsequent codeword segment is read from the circular buffer 104, interleaved using matrix 300, and mapped to the corresponding modulation symbol vector 302, which is then mapped to the MIMO layer 304 for transmission to the receiver.

[0085] According to the above transmission process, the first codeword segment c0 is transmitted through multiple independent bit channels (where each bit channel is associated with the Q-value of the bits read from matrix 300). m The bits in the tuple are sent on the physical resources (the resources corresponding to the bits in the tuple), and their capacity—referred to as the bit capacity in this paper—is given by Q. m tuple The middle is used to select the modulation symbol d S The bit position and the SNR of the corresponding MIMO layer are used to determine Q. m tuple Bit capacity of the l-th bit Defined as a given bit b l The corresponding log-likelihood ratio (LLR) λ l Mutual information between them. It can be written mathematically as:

[0086]

[0087] Where I(X,Y) represents the mutual information between random variables X and Y, and l is Q m The positions of bits in a tuple (l = 1, ..., Q) m And the log-likelihood ratio (LLR)λ l The definition is as follows:

[0088]

[0089] Where y = x + w is the modulation symbol received by the receiver, and w is a variable with variance. Additive white Gaussian noise (AWGN), P(b l =0|y) is bit b in y l The probability that P(b) is 0, and P(b) l =1|y) is bit b in y l The probability of being 1.

[0090] Figure 4 The bit capacity for different modulation schemes used in transmitter 100 is shown. and (Assuming a unit average modulation symbol energy) dependency. Here, l∈{1,…,Q} m} is Q m The bit positions within a tuple. Specifically, Figure 4 The dependencies for the following modulation schemes are shown. BPSK(Q m =1): QPSK(Q m =2): and QAM, where Q m ∈{4,6,8} (which correspond to 16QAM, 64QAM, and 256QAM respectively). For example... Figure 4 As shown, with any QAM modulation scheme Q m The bit channel corresponding to the initial position in the tuple This corresponds to the bit channel with the highest bit capacity. More precisely, it applies to any SNR and any QAM modulation order Q. m And bit positions l1, l2 ∈ {1, …, Q} m If l2 > l1, then we can obtain... It can also be written

[0091]

[0092] Thus, the interleaver 106 maps the information bits to each Q. m A high-capacity bit channel within a tuple. However, interleaver 106 ignores Q. m The tuples are then mapped to MIMO layers 304 with different SNRs. Since the SNR imbalance between MIMO layers 304 can be significant, the information bits are mapped to Q bits regardless of the layer SNR. mThe initial bits of a tuple are insufficient to guarantee a high bit capacity for information bits. In fact, when the SNR imbalance between MIMO layers 304 is significant, transmitting a Q-bit on a high SNR MIMO layer... m The last bit of the tuple is compared to the other Q transmitted on a low SNR MIMO layer. m The initial bits of a tuple have a higher capacity.

[0093] To overcome the aforementioned drawbacks, instead of transmitting a single codeword, multiple shorter codewords can be transmitted across multiple MIMO layers, with each shorter codeword used for one MIMO layer or a group of MIMO layers with similar SNR. By doing so, each shorter codeword will be encoded and modulated using the optimal code rate and modulation order to match the layer SNR. However, this solution has the following main disadvantages:

[0094] 1. Compared to transmitting long codewords, transmitting shorter codewords results in smaller coding gain;

[0095] 2. Scheduling multiple shorter codewords instead of a single codeword requires sending more scheduling messages on the control channel, resulting in a larger amount of control information and potential control channel congestion.

[0096] The exemplary embodiments disclosed herein provide technical solutions that can alleviate or even eliminate the aforementioned drawbacks inherent in the prior art. Specifically, the technical solutions disclosed herein relate to a codeword bit interleaving scheme that involves dividing the columns of an interleaving matrix (hereinafter referred to as the matrix) into at least two disjoint column groups based on the transmission quality (e.g., SNR) of the data transmission layer (e.g., MIMO layer). If codeword bits are transmitted on the same layer or different layers with similar transmission quality, the two columns are in the same column group. Then, starting with writing information bits into the column group corresponding to the high-quality data transmission layer, these column groups are filled with codeword bits. After all information bits have been written, parity bits are written into the remaining column groups. Afterward, all column groups are merged to restore the initial column arrangement of the matrix, and codeword bits are read row by row from the matrix and mapped to modulation symbols. The modulation symbols are then mapped to the data transmission layer itself. By doing so, the information bits of the codewords can be allocated to the high-quality data transmission layer, thereby providing better decoding performance compared to interleaver 106.

[0097] Figure 5A block diagram of a wireless communication device 500 according to an exemplary embodiment is shown. The device 500 can be implemented as a UE or a RAN node, or as part of a UE or a RAN node. The device 500 includes a processor 502, a memory 504, and a transceiver 506. The memory 504 stores processor-executable instructions 508, which, when executed by the processor 502, cause the processor 502 to receive a codeword 510 and obtain a layer-mapped modulation symbol 512, as will be described in more detail below. It should be noted that the configuration as described below... Figure 5 The number, arrangement, and interconnection of the building elements of the illustrated device 500 are not intended as any limitation on the invention, but are merely provided to offer a general concept of how these building elements can be implemented within the device 500. For example, processor 502 can be replaced by several processors, and memory 504 can be implemented as a single storage device coupled to device 500. Furthermore, transceiver 506 can be implemented as two devices, one for receiving operations and the other for transmitting operations. Regardless of the implementation, transceiver 506 is intended to be able to perform the various operations required to transmit layer-mapped modulation symbols 512, such as OFDM modulation.

[0098] Figure 6 A block diagram of a processor 502 according to an exemplary embodiment is shown. The processor 502 includes components such as a circular buffer 602, an interleaver 604, a modulator 606, and a layer mapper 608. The circular buffer 602, interleaver 604, modulator 606, and layer mapper 608 serve the same purpose as the circular buffer 104, interleaver 106, modulator 108, and layer mapper 110 included in the transmitter 100 described above. The processor 502 may optionally include an encoder for obtaining codeword 510. The components of the processor 502 can be implemented as hardware and / or software. Hardware implementation of the components can be provided using a CPU, a general-purpose processor, a single-purpose processor, a microcontroller, a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal processor (DSP), a complex programmable logic device, or any combination thereof. As an example, the components of the processor 502 can be implemented as two or more microprocessors. The software implementation includes implementing the function of each component of the processor 502 by executing corresponding code, programs, routines, commands, etc., which are stored in the memory 504, for example, together with the processor executable instructions 506.

[0099] Return to Figure 5 The memory 504 can be implemented as a classic non-volatile or volatile memory used in modern electronic computing machines. As examples, non-volatile memory may include read-only memory (ROM), ferroelectric random-access memory (RAM), programmable ROM (PROM), electrically erasable PROM (EEPROM), solid-state drive (SSD), flash memory, disk storage devices (e.g., hard disk drives and magnetic tape), optical disk storage devices (e.g., CD, DVD, and Blu-ray discs), etc. As for volatile memory, examples include dynamic RAM, synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), static RAM, etc.

[0100] As for the processor-executable instructions 506 stored in memory 504, they can be configured to be used as computer-executable code to cause processor 502 to execute aspects of the present invention. The computer-executable code for performing operations or steps related to aspects of the present invention can be written in any combination of one or more programming languages, such as Java, C++, etc. In some examples, the computer-executable code can be in the form of a high-level language or in a pre-compiled form, and can be dynamically generated on-the-fly by an interpreter (also pre-stored in memory 504).

[0101] Figure 7 A flowchart of a wireless communication method 700 according to an exemplary embodiment is shown. Method 700 itself describes the operation of device 500. Figure 7As shown, method 700 begins at step S702, in which processor 502 receives codeword 510 to be transmitted through a data transmission layer. Each data transmission layer in the data transmission layer has transmission quality. A data transmission layer can be represented by a MIMO layer; however, the invention is not limited to this example, and those skilled in the art will readily recognize that a data transmission layer can refer to any spatial layer on which information can be transmitted simultaneously. As for transmission quality, it can refer to any metric in the art used to compare the level of a desired signal with the level of background noise. A non-limiting example of transmission quality is SNR. Codeword 510 can be obtained by processor 502 itself or received by processor 502 from an external source (e.g., from a remote server used to transmit codeword 510 to transceiver 506, which in turn provides the codeword to processor 502). The codeword is obtained using linear codes. Non-limiting examples of linear codes include turbo codes, systematic codes, systematic polar codes, LDPC codes, etc. Codeword 510 has a codeword length E and includes codeword bits. The codeword bits include at least one information bit and at least one parity bit. Step S702 may further include: if the segmented transmission of codeword 510 is scheduled, storing the codeword in a circular buffer 602.

[0102] Once codeword 510 is received, method 700 proceeds to step S704, in which processor 502, i.e., interleaver 604, interleaves (or in other words, rearranges / swaps) the codeword bits of codeword 510 using a matrix with n rows and k columns, where n and k are chosen based on a predefined modulation scheme and codeword length E. This matrix can be created in the same way as matrix 300 used by interleaver 106 in transmitter 100. Typically, n can be equal to the modulation order Q of the predefined modulation scheme. m k is determined by applying a floor function to the codeword length E and the modulation order Q. m This is obtained by comparing the two. Non-limiting examples of predefined modulation schemes include QAM, PSK, and QPSK modulation schemes. Each column of the matrix used in step S704 of method 700 corresponds to a data transmission layer, which allows the columns to be grouped based on the transmission quality of the data transmission layer, as described below.

[0103] The interleaving step S704 is performed as follows: First, the interleaver 604 arranges columns corresponding to data transmission layers with transmission quality equal to or higher than a threshold into at least one first column group, and arranges columns corresponding to data transmission layers with transmission quality lower than the threshold into at least one second column group. The threshold depends on the specific application and can be any transmission quality value between the minimum and maximum transmission quality of the data transmission layer (e.g., any SNR between the minimum and maximum SNR of the available MIMO layer to be used for transmission). Then, starting with writing information bits row by row into the first column group, the interleaver 604 writes codeword bits row by row into the first and second column groups. Afterward, the interleaver 604 merges the first and second column groups to recover the matrix. This recovery means returning to the initial column arrangement in the matrix, but now the columns have been filled with codeword bits. The interleaving step S704 ends when the interleaver 604 reads codeword bits column by column from the matrix.

[0104] When the interleaving step S704 ends, method 700 proceeds to step S706, in which processor 502, i.e., modulator 606, obtains the modulation symbols of the codeword bits read from each column of the matrix using a predefined modulation scheme. Then, the next step S708 of method 700 is initiated, in which processor 502, i.e., layer mapper 608, maps the modulation symbols obtained in step S706 to the data transmission layer. Next, method 700 proceeds to step S710, in which transceiver 506 transmits the mapped modulation symbols to the target wireless communication device (e.g., another UE or gNB).

[0105] In one exemplary embodiment, method 700 may include an additional step in which processor 502 (e.g., including dedicated additional hardware or software components) determines the transmission quality of the data transmission layer in advance, i.e., before step S702 or step S704, based on an uplink reference signal in the case of TDD communication or based on a downlink reference signal in the case of FDD communication. For example, if device 500 is a gNB using a MIMO method when performing TDD communication, downlink / uplink channel reciprocity is assumed, and therefore the gNB determines the downlink SNR by calculating the singular value decomposition of the MIMO channel matrix obtained based on the uplink reference signal. If device 500 is a UE performing FDD communication, the UE performs channel estimation based on the downlink reference signal, i.e., determines the SNR.

[0106] In one exemplary embodiment, method 700 may include an additional step in which processor 502 (e.g., dedicated additional hardware or software components included therein) determines the modulation order Q of a predefined modulation scheme based on the transmission quality of the data transmission layer prior to interleaving step S704. m By doing so, a modulation order Q that is more suitable for a given data transmission layer can be selected. m This improves the efficiency of the interlacing step S704.

[0107] In one exemplary embodiment, the predefined modulation scheme can define the Q of the codeword bits to be read from each column of the matrix in the interleaving step S704. m The mapping from tuples to modulation symbols. In this embodiment, method 700 may include an additional step in which processor 502 (e.g., dedicated additional hardware or software components included) determines each Q based on the transmission quality of the data transmission layer. m The bit capacity of the codeword bits in the tuple is determined, and the determined bit capacity is used to determine: (i) the number G of columns of the matrix to be arranged into the first and second column groups, and (ii) the correspondence between each data transmission layer and the first or second column group. By doing so, the efficiency of grouping the columns of the matrix used in the interleaving step S704 can be improved, thereby improving the efficiency of the interleaving step S704 itself.

[0108] In one exemplary embodiment, prior to the transmission step S710, method 700 may include an additional step in which processor 502 (e.g., dedicated additional hardware or software components included) generates a control message and transmits the control message to the target wireless communication device. The control message may include at least one of the following: modulation order Q. m The codeword length E; the number G of at least one first column group and at least one second column group used when interleaving codeword bits; and the correspondence between each data transmission layer and at least one first column group or at least one second column group. By doing so, information about the codeword bit interleaving scheme used by device 100 when performing method 700 can be provided to the target wireless communication device, thereby enabling the target wireless communication device to perform deinterleaving and thus decode the codeword bits more efficiently and faster.

[0109] Such control messages can be sent to the target communication device using the following three control signaling methods:

[0110] 1) According to the first control signaling method, the column grouping configuration g = (γ1,…,γ) of the indication column group is included in the control field of the control message. v Each element γv These are all integers between 1 and the number of column groups G, indicating the column group for the corresponding column. For example, interleaver 604 configured with G=1, g=(1,…,1) overlaps with interleaver 106. The first control signaling method may generate non-negligible control information overhead because g can take the value v. v There are 10 distinct values, and the size needs to be at least 1. Bit field of a bit.

[0111] 2) According to the second control signaling method, it is assumed that the wireless communication device 100 and the target wireless communication device are used to sort the data transmission layers in the same order based on their independently determined layer SNRs. Once the layers are sorted according to their SNRs, for each pair of adjacent layers, the control bits indicated in the control message indicate whether the two layers are in the same column group. Since there are v-1 pairs of adjacent layers, a control field of size v-1 bits is sufficient. However, the second control signaling method has the following drawback: the wireless communication device 100 and the target wireless communication device may produce different layer SNR estimates, which may lead to different layer orders. However, layer swapping occurs when the SNR difference between two swapped layers is small, i.e., when the two layers correspond to the same column group. Two layers with a large SNR difference will never be swapped, as this would imply a large SNR estimation error. The swapping of layers assigned to the same column group is independent of interleaving / deinterleaving; therefore, the second control signaling method works even with SNR estimation errors.

[0112] 3) According to the third control signaling method, it is assumed that the wireless communication device 100 and the target wireless communication device are used to: sort the data transmission layers in the same order based on their independently determined layer SNRs, in order to determine the same layer sequence sorted according to their own SNRs. The control field represents: the number of groups G between 1 and v; G-1 maximum SNR gaps between consecutive layers in the sorted layer sequence are used as group separation SNR boundaries. Since there can be at most v column groups, a control field of size log2 v bits is sufficient in the control message.

[0113] Figure 8 The interleaving step S704, modulation step S706, and mapping step S708 of method 700 when using two column groups are described. Figure 8 In the example shown, matrix 800 is created in the same way as matrix 300, that is, matrix 800 includes Q. m Each row and S = E / Q mEach column. Unlike interleaver 106 (hereinafter referred to as conventional interleaver 106 to highlight its relationship with the prior art), in step S704, interleaver 604 divides matrix 800 into G = 2 separate column groups 802 and 804. Again, it should be noted that if two columns correspond to the same layer or different layers with similar transmission quality (e.g., SNR), then these two columns are located in the same column group. Figure 3 Similarly, the columns of matrix 800 associated with the corresponding layer are filled using different dot patterns. Figure 8 As shown (e.g., the column with the densest dotted pattern filling corresponds to layer 1). Column groups 802 and 804 can be arranged in descending order of transmission quality for their respective layers. Figure 8 In this context, it is assumed that the first column group 802 consists of the following columns of matrix 800: the columns correspond to layers with higher transmission quality (e.g., in the case of transmission quality represented by SNR, these layers are above a specific threshold in decibels (dB)).

[0114] See Figure 8 In G=2 steps, the codeword 510 is written into matrix 800. In the first step, starting with writing the information bits, the codeword bits are... Write the first column group 802; here, E1 is the total number of bits in the first column group 802. In the second step, write the subsequent codeword bits. Write the second column group 804, where E2 is the total number of bits in the second column group. If more than two column groups are used, this process continues until the last step, when the remaining codeword bits are written to the Gth column group. In all steps, the codeword bits are written to matrix 800 row by row from left to right, starting from the top row.

[0115] Once all the codeword bits of codeword 510 have been written into column groups 802 and 804, the interleaver 604 performs the following: merging column groups 802 and 804 to restore matrix 800, that is, restoring the initial column arrangement of the matrix, which is in... Figure 8 The matrix 806 is used to represent the codeword bits. Reading the codeword bits from the recovered matrix 806 is done by interleaver 604 in the same way as regular interleaver 106, i.e., by reading the recovered matrix 806 column by column from top to bottom, starting from the leftmost column, to obtain the output b = (b1,…,b...). E The s-th column (s=1,…,S) of the recovered matrix 806 produces Q. m Bit tuple Then, in step S706, the tuple is mapped to the complex modulation symbol d by modulator 606. s Therefore, it is proved that any Q mThe initial bits of the tuple all represent information bits. Modulator 606 generates modulation symbol vector 810, i.e., d = (d1, ..., d2). S Next, in step S708, the modulation symbol vector is mapped to the data transmission layer by the layer mapper 608, thereby obtaining the layer-mapped modulation symbol 512.

[0116] If more than two column groups are formed in the interleaving step S704, and v g S is used as the number of data transmission layers in the g-th column group (g = 1, ..., G). g =Sv g / v is the number of columns in the g-th column group of matrix 800, and E g =S g Q m It is the total number of bits in the g-th column group.

[0117] It should be noted that if a single column group is used (i.e., G=1), the interleaver 604 writes the codeword bits into the matrix 800 in the same manner as the regular interleaver 106. In this case, reading the codeword bits from the matrix 800 is also done in the same way. Therefore, the interleaver 604 configured with one column group is exactly the same as the regular interleaver 106.

[0118] For the transmission of codeword 510, whether it is more convenient to use a conventional interleaver 106 or an interleaver 604 is based on the metric Δ. CC The metric (ρ, g) is used to determine the increase in the total bit capacity of codeword 510 provided by interleaver 604 relative to conventional interleaver 106 (normalized by codeword length E). Here, ρ = (SNR1, ..., SNR) v The layer contains the SNR (SNR is an example of transmission quality), and g = (γ1, ..., γ). v The indicator column group is as described above. Δ CC The definition is given as follows

[0119]

[0120] The summation is calculated using the information bit indices e = 1, ..., K in codeword 510, and β is discussed in the context of... Figure 3 The bit capacity is as defined above; 604 (e) gives the Q when using interleaver 604 m The position of the e-th information bit in the tuple, l 106 (e) gives the Q when using the conventional interleaver 106 m The position of the e-th information bit in the tuple; SNR 604 (e) and SNR 106(e) represent the SNR of the e-th information bit when using interleaver 604 and regular interleaver 106, respectively. In the above equations, β is independent of the interleaver used, and the different mappings of the interleavers are achieved through the l of interleaver 604. 604 (e) SNR 604 (e) and the l of conventional weaver 106 106 (e) SNR 106 (e) Captured. 106 (e) and SNR 106 (e) is through application Figure 3 The image shows the result of a conventional interleaver mapping. 604 (e) and SNR 604 (e) is through application Figure 8 The interleaver mapping shown is obtained.

[0121] Numerical evaluation shows that Δ CC It provides a good indication of the gain obtained through the interleaver 604—when Δ CC When the time is positive, the interleaver 604 performs better than the conventional interleaver 106, while when the time is negative... CC This indicates that the performance of the conventional interleaver 106 is better. Therefore, it can be based on Δ CC The sign of the interleaver is used to select the interleaver.

[0122] Now let's consider an explanation of how to use Δ CC Numerical examples.

[0123] Assume codeword 510 is obtained using LDPC coding and requires 16QAM (Q16Q2) to be applied on two data transmission layers (v=2) (e.g., MIMO layers). m =4) at bitrate R C =1 / 2 of the codeword 510 is transmitted in segments. Assume an average SNR of 7dB. Further assume that in the first transmission of a codeword segment of codeword 510, there is a small SNR difference Δ between the two layers. SNR =2dB — SNR1 = 8dB and SNR2 = 6dB, while in the second transmission of another codeword segment of codeword 510, the SNR difference between the two layers is Δ SNR =10dB — SNR1 = 12dB and SNR2 = 2dB. Interleaver 604 produces two column groups, each containing one column (i.e., g = (1,2)). Table 2 below summarizes the above evaluation assumptions.

[0124] Table 2 Evaluations in the above numerical examples

[0125]

[0126] Figure 9 This demonstrates the application of 16QAM(Q m Dependencies of the above numerical examples (=4) exist Figure 9 In the context of the SNR difference between the two layers in the first and second transmission cases, the vertical line pairs corresponding to the dependency relationship are shown. The intersections are used to obtain the bit capacity of each codeword bit in each codeword bit tuple. In this case, each 4-codeword bit tuple is represented by four codeword bits b1, b2, b3, and b4, where b1 is the first bit in the 4-tuple, b2 is the second bit, and so on. In the first transmission, when using the first data transmission layer, the bit capacity of codeword bits b1 and b2 is 0.78, and the bit capacity of codeword bits b3 and b4 is 0.56; while when using the second data transmission layer, the bit capacity of codeword bits b1 and b2 is 0.68, and the bit capacity of codeword bits b3 and b4 is 0.4. In the second transmission, when using the first data transmission layer, the bit capacity of codeword bits b1 and b2 is 0.93, and the bit capacity of codeword bits b3 and b4 is 0.86; while when using the second data transmission layer, the bit capacity of codeword bits b1 and b2 is 0.47, and the bit capacity of codeword bits b3 and b4 is 0.16.

[0127] Figure 10 Matrices 1000 and 1002, used by conventional interleaver 106 and interleaver 604 respectively, are shown, along with the corresponding bit capacity for the first transmission in the above digital example. Figure 10 In this example, different dot patterns are used again to show the correspondence between the columns of matrices 1000 and 1002 and the two data transmission layers (e.g., the column with the densest dot pattern corresponds to the first data transmission layer). Furthermore, bold numbers indicate the positions of the information bits. Since the code rate is 1 / 2, the information bits occupy half of each matrix regardless of the interleaver used. The regular interleaver 106 writes the information bits row by row into all columns (i.e., in other words, across both data transmission layers), thus filling the two higher rows with information bits (see [reference]). Figure 10 (The upper part). Therefore, half of the information bits have a bit capacity of 0.78, while the other half have a bit capacity of 0.68. Unlike the conventional interleaver 106, the interleaver 604 only writes the information bits to the column corresponding to the first data transmission layer (see the upper part). Figure 10 (The lower part). This means that half of the information bits have a bit capacity of 0.78, while the other half of the information bits have a bit capacity of 0.56.

[0128] Now let's calculate Δ by applying the above equation. CC Therefore, it is necessary to determine Q. mposition l in tuple 604 (e) and l 106 (e) and the SNR value of the data transmission layer on which the e-th bit (e = 1, ..., K) is transmitted for each information bit. 604 (e) and SNR 106 (e). Value l 106 (e) and SNR 106 (e) By Figure 3 The interleaver mapping shown is obtained; the corresponding bit capacity is obtained from... Figure 10 The upper part is determined. Value l 604 (e) and SNR 604 (e) By Figure 8 The interleaver mapping shown is obtained; the corresponding bit capacity is obtained from... Figure 10 The lower part is determined. These values ​​are shown in Table 3 below.

[0129] Table 3 lists the bit positions, SNR, and corresponding bit capacity for the first transmission.

[0130]

[0131]

[0132] Δ CC This is obtained by summing the numbers in the rightmost column of Table 3 and dividing the result by E. In the rightmost column of Table 3, K / 4 values ​​= 0, K / 4 values ​​= 0.1, K / 4 values ​​= -0.12, and K / 4 values ​​= -0.22. Therefore, Δ for the first transmission is obtained as follows. CC :

[0133]

[0134] K / E=R has already been used. C =1 / 2. Negative Δ CC This indicates that the conventional interleaver 106 provides better performance compared to the interleaver 604.

[0135] Figure 11 Matrices 1100 and 1102, used by conventional interleaver 106 and interleaver 604 respectively, are shown, along with the corresponding bit capacity for the second transmission in the digital example above. Figure 11 In this example, different dot patterns are used again to show the correspondence between the columns of matrices 1100 and 1102 and the two data transmission layers (e.g., the column with the densest dot pattern corresponds to the first data transmission layer). Furthermore, bold numbers again indicate the position of information bits. For example... Figure 11As shown, when using the conventional interleaver 106, half of the information bits have a bit capacity of 0.93, and the other half have a bit capacity of 0.47. When using the interleaver 604, half of the information bits have a bit capacity of 0.93, and the other half have a bit capacity of 0.86. Similar to Table 3, Table 4 below lists Q... m position l in tuple 604 (e) and l 106 (e) transmits the SNR values ​​of the two data transmission layers on which the e-th bit (e = 1, ..., K) is transmitted. 604 (e) and SNR 106 (e), and the bit capacity for the second transmission.

[0136] Table 4 lists the bit positions, SNR, and corresponding bit capacities for the second transmission.

[0137]

[0138]

[0139] Δ CC This is obtained by summing the numbers in the rightmost column of Table 4 and dividing the result by E. In the rightmost column of Table 4, K / 4 values ​​= 0, K / 4 values ​​= 0.46, K / 4 values ​​= -0.07, and K / 4 values ​​= 0.39. Therefore, Δ for the second transmission is obtained as follows. CC :

[0140]

[0141] The above positive Δ CC This indicates that the interleaver 604 provides better performance compared to the conventional interleaver 106.

[0142] Figure 12 The relationship between block error rate (BLER) and SNR is shown for the two transmissions in the above digital example. Figure 12 In the diagram, the dashed line corresponds to the regular interleaver 106, while the solid line corresponds to the interleaver 604. The dependency BLER (SNR) confirms this conclusion. For the first transmission (SNR = 8dB), the BLER of the regular interleaver 106 is smaller than that of the interleaver 604. For the second transmission (SNR = 12dB), the BLER of the interleaver 604 is smaller. It can be further concluded that data transmission layers with similar SNRs should be located in the same column group, while data transmission layers with significantly different SNRs should be located in different column groups.

[0143] Therefore, the above numerical examples clearly demonstrate how to base them on Δ CCThe sign of (ρ,g) is used to determine the relationship between regular interleaver 106 and interleaver 604. Meanwhile, Δ CC (ρ,g) enables the finding of the optimal column grouping configuration g. * This can be achieved as follows:

[0144] g * (ρ)=argmax g Δ CC (ρ,g).

[0145] If the optimal column grouping result obtained from the above equation is g * = (1,…,1), then all columns are in the same column group, which means that the regular interleaver 106 is the optimal choice, i.e., it provides the best performance. When g * When ≠(1,…,1), the optimal column grouping g is configured. * The 604 interleaver achieves optimal performance.

[0146] Δ can be calculated by configuring g to group all allowed columns. CC (ρ, g) is used to numerically configure the optimal column grouping for searching. * Typically, since there are up to v column groups, each of the v elements in g can take values ​​between 1 and v. For a given column grouping configuration, this will result in multiple values ​​on the order of v. v The allowed value is a fairly large number, even for small v. As mentioned above, by reviewing that data transmission layers with similar SNRs can be grouped in the same column, the search complexity can be greatly reduced. Therefore, the following search strategy can be applied:

[0147] 1. Sort them according to the SNR of the data transmission layer;

[0148] 2. For each pair of adjacent data transmission layers, evaluate whether these data transmission layers should be in the same column group.

[0149] Because there are v-1 pairs of adjacent data transmission layers, the number of allowed column grouping configurations is limited from v v Dropped to 2 v-1 Therefore, it is only necessary to adjust Δ CC (ρ,g) undergoes 2 v-1 This evaluation is conducted once. In NR, the maximum number of MIMO layers (which is an example of a data transmission layer) used for a codeword is v = 4; therefore, the order of magnitude of the number of allowed column grouping configurations will be v. v =256. Using the above search strategy, the number of allowed column grouping configurations is reduced to 2. v-1 =8.

[0150] In the above digital example, the performance of LDPC-coded transmission was evaluated for a MIMO channel with v layers and G column groups, where each MIMO layer has the same SNR within each column group. Without loss of generality, it can be assumed that the SNR of the first column group is higher than that of the other column groups, and that the SNR of the g-th column group is Δ smaller than that of the first column group. SNR,g [dB]. The channel model is represented by additive white Gaussian noise (AWGN). Table 5 below summarizes the performance evaluation assumptions. Performance gains are based on achieving BLER ≤ 10. -2 The required SNR is evaluated.

[0151] Table 5 Summary of Simulation Parameters (Subset of Evaluation Combinations)

[0152]

[0153] Figure 13A and Figure 13B The BLER performance of LDPC-coded transmissions with QPSK modulation and 16QAM modulation for v=2 MIMO layers and G=2 column groups is shown. Figure 13A and Figure 13B In the diagram, the solid curve shows the performance obtained using interleaver 604, while the dashed curve shows the performance obtained using conventional interleaver 106. The SNR difference between MIMO layers is Δ. SNR =10dB. It can be observed that the interleaver 604 consistently outperforms the conventional interleaver 106. With QPSK modulation and LDPC code rate 1 / 2, an SNR gain of up to 0.9dB is observed (see...). Figure 13A In the case of 16QAM, the SNR gain is slightly smaller, but still significant (see [reference]). Figure 13B ).

[0154] exist Figure 13A and Figure 13B It was observed that higher-order modulation provides lower gain. With a small layer SNR difference, the conventional interleaver 106 has already mapped the information bits to the bit channel with the highest bit capacity. Therefore, there is no gain. To obtain gain using higher-order modulation, the layer SNR difference must be large enough that the minimum bit capacity on the higher SNR layer is greater than the maximum bit capacity on the lower SNR layer. Therefore, for each modulation order, there exists a minimum SNR difference below which the interleaver 604 provides no gain, or even incurs a loss. For QPSK, the minimum SNR difference is 0 dB; for 16QAM, it is approximately 6 dB; and for 64QAM, it is approximately 10 dB. Therefore, for a given fixed SNR difference, the higher the modulation order, the smaller the gain.

[0155] exist Figure 13A and Figure 13B This was also observed in [the study], for any given modulation and a given Δ. SNR Maximum gain is achieved by utilizing the bit rate. The gain is obtained, but for code rates of 1 / 4 and 2 / 3, the gain is smaller. This behavior relates to the fundamental observation that optimal belief propagation decoding performance is obtained when information bits are mapped to bit channels with the highest bit capacity.

[0156] Figure 14A and Figure 14B It shows the target and Figure 13A and Figure 13B The code rate and modulation used are the same as those used in the modulation. CC (SNR). Curve Δ CC (SNR) has multiple branches—one branch for each bit rate. Figure 14A and Figure 14B In the diagram, each branch is shown at BLER=10. –2 Within the SNR range around the SNR point. It can be seen that the Δ corresponds to the branch with a code rate of 1 / 2. CC It is higher than other branches. Figure 13A , Figure 13B as well as Figure 14A , Figure 14B The comparison reveals the Δ of interleaver 604 CC A clear correlation exists between gain and Δ. For a code rate of 1 / 2, the gain and Δ... CC For higher bit rates, Δ CC It depends on the bitrate and SNR of all MIMO layers. This makes it more difficult to determine the optimal bitrate.

[0157] Figure 15A and Figure 15B The BLER performance of LDPC-coded transmissions with QPSK modulation and 16QAM modulation is shown for different layer SNR differences. Figure 15A and Figure 15B In the diagram, the solid curve shows the BLER performance obtained using interleaver 604, while the dashed curve shows the BLER performance obtained using conventional interleaver 106. In this case, the code rate is R0. C =1 / 2. The performance of interleaver 604 is consistently superior to that of conventional interleaver 106. In QPSK and Δ SNR At 15dB, an SNR gain of up to 2.7dB was observed (see [reference]). Figure 15A In the case of 16QAM, when Δ SNR At 15dB, an SNR gain of up to 1.7dB was observed (see [reference]). Figure 15B ).

[0158] It should be noted that each step or operation, or any combination of steps or operations, of method 700 can be implemented by various means, such as hardware, firmware, and / or software. As an example, one or more of the steps or operations described above can be embodied by processor-executable instructions, data structures, program modules, and other suitable data representations. Furthermore, the executable instructions embodying the steps or operations described above can be stored on a corresponding data carrier and executed by processor 502. This data carrier can be implemented as any computer-readable storage medium that can be read by the at least one processor to execute processor-executable instructions. Such a computer-readable storage medium can include both volatile and non-volatile media, removable and non-removable media. As an example, and not a limitation, a computer-readable medium includes media implemented in any method or technology suitable for storing information. More specifically, practical examples of computer-readable media include, but are not limited to, information delivery media, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD), holographic media or other optical storage, magnetic tape, magnetic tape cassette, disk storage devices, and other magnetic storage devices.

[0159] While exemplary embodiments of the invention have been described herein, it should be noted that various changes and modifications may be made to the embodiments of the invention without departing from the scope of legal protection defined by the appended claims. In the appended claims, the word "comprising" does not exclude other elements or operations, and the indefinite articles "a" or "an" do not exclude a plurality. The enumeration of certain measures in dissimilar dependent claims does not imply that combinations of these measures cannot be used advantageously.

Claims

1. An apparatus (500) for a wireless communication system, characterized in that, include: Processor (502); A memory (504) coupled to the processor (502) and used to store processor-executable instructions (508), wherein the processor (502) is used to perform the following operations when executing the processor-executable instructions (508): Receive codewords (510) to be transmitted through data transmission layers, wherein each data transmission layer has transmission quality, the codewords (510) are obtained using linear codes, and the codewords (510) have a codeword length. It also includes codeword bits, which include at least one information bit and at least one parity bit; By using individual lines and A matrix of 800 columns is used to interleave the codeword bits, where and Based on the predefined modulation scheme and the codeword length Selected, each column in the columns corresponds to one of the data transmission layers; The columns corresponding to data transmission layers with transmission quality equal to or higher than a threshold are arranged into at least one first column group (802), wherein the threshold is an independently determined SNR between the minimum signal-to-noise ratio (SNR) and the maximum SNR of the available data transmission layers, the at least one information bit is selectively mapped into the at least one first column group (802), the data transmission layers are ordered based on the SNR between the minimum SNR and the maximum SNR, adjacent data transmission layers are paired, and the control bits indicated in the control message indicate whether each pair of adjacent data transmission layers is in the same column group; The columns corresponding to data transmission layers with transmission quality below the threshold are arranged into at least one second column group (804), wherein at least one parity bit is selectively mapped to the at least one second column group (804); The codeword bits are written row by row into the at least one first column group (802) and the at least one second column group (804). Merge the at least one first column group (802) and the at least one second column group (804) to recover the matrix (800); and Read the codeword bits column by column from the matrix (800); Modulation symbols (810) of codeword bits read from each column of the matrix are obtained by using the predefined modulation scheme. as well as Map the modulation symbol (810) to the data transmission layer; as well as A transceiver (506) is used to send mapped modulation symbols (512) and the control message to a target wireless communication device.

2. The apparatus (500) according to claim 1, characterized in that, The predefined modulation scheme has a modulation order. , and among them Equal to the modulation order ,and This is achieved by applying a floor function (either floor function or floor function) to the codeword length. With the modulation order It is obtained by the ratio of [the two].

3. The apparatus (500) according to claim 2, characterized in that, The processor (502) is further configured to: determine the modulation order of the predefined modulation scheme based on the transmission quality of the data transmission layer before the interleaving. .

4. The apparatus (500) according to claim 2 or 3, characterized in that, The predefined modulation scheme defines the codeword bits of each column of the matrix (800). The mapping of tuples to the modulation symbols (810), and wherein the processor (502) is further used for: Determine each based on the transmission quality of the data transmission layer. The bit capacity of the codeword bits in a tuple; as well as Based on the determined bit capacity, determine: (i) the number of columns of the matrix (800) that will be arranged into the at least one first column group (802) and the at least one second column group (804). (ii) the correspondence between each data transmission layer in the data transmission layer and the at least one first column group (802) or the at least one second column group (804).

5. The apparatus (500) according to claim 4, characterized in that, The processor (502) is also configured to perform the following operations before causing the transceiver to transmit the mapped modulation symbol (512): The control message is generated, and the control message includes at least one of the following: The modulation order ; The codeword length ; The number of the at least one first column group (802) and the at least one second column group (804) used when interleaving the codeword bits ;as well as The correspondence between each data transmission layer in the data transmission layer and the at least one first column group (802) or the at least one second column group (804).

6. The apparatus (500) according to claim 1, characterized in that, The codeword (510) is obtained using a linear code selected from one of turbo codes, systematic codes, systematic polar codes and low-density parity-check (LDPC) codes (200).

7. The apparatus (500) according to claim 1, characterized in that, The predefined modulation scheme includes one of the following: Quadrature Amplitude Modulation (QAM), Phase Shift Keying (PSK), and Quadrature PSK (QPSK).

8. The apparatus (500) according to claim 1, characterized in that, The processor (502) is also configured to: predetermine the transmission quality of the data transmission layer based on the uplink reference signal in the case of time division duplex (TDD) communication, or based on the downlink reference signal in the case of frequency division duplex (FDD) communication.

9. The apparatus (500) according to claim 1, characterized in that, The data transmission layer includes a multiple-input multiple-output (MIMO) spatial layer.

10. A method (700) for wireless communication, characterized in that, include: Receive (S702) a codeword (510) to be transmitted through a data transmission layer, wherein each data transmission layer in the data transmission layer has a transmission quality, the codeword (510) is obtained using a linear code, and the codeword (510) has a codeword length. It also includes codeword bits, which include at least one information bit and at least one parity bit; By using individual lines and A matrix (800) of columns is used to interleave (S704) the codeword bits, where and Based on the predefined modulation scheme and the codeword length Selected, each column in the columns corresponds to one of the data transmission layers; The columns corresponding to data transmission layers with transmission quality equal to or higher than a threshold are arranged into at least one first column group (802), wherein the threshold is an independently determined SNR between the minimum signal-to-noise ratio (SNR) and the maximum SNR of the available data transmission layers, the at least one information bit is selectively mapped into the at least one first column group (802), the data transmission layers are ordered based on the SNR between the minimum SNR and the maximum SNR, adjacent data transmission layers are paired, and the control bits indicated in the control message indicate whether each pair of adjacent data transmission layers is in the same column group; The columns corresponding to data transmission layers with transmission quality below the threshold are arranged into at least one second column group (804), wherein at least one parity bit is selectively mapped to the at least one second column group (804); The codeword bits are written row by row into the at least one first column group (802) and the at least one second column group (804). Merge the at least one first column group (802) and the at least one second column group (804) to recover the matrix (800); and Read the codeword bits column by column from the matrix (800); Modulation symbols (810) of codeword bits read from each column of the matrix (800) are obtained (S706) by using the predefined modulation scheme. Map the modulation symbol (810) to the data transmission layer (S708); as well as The mapped modulation symbol (512) and the control message are sent to the target wireless communication device (S710).

11. The method (700) according to claim 10, characterized in that, The predefined modulation scheme has a modulation order. , and among them Equal to the modulation order ,and This is achieved by applying a floor function (either floor function or floor function) to the codeword length. With the modulation order It is obtained by the ratio of [the two].

12. The method (700) according to claim 11, characterized in that, Also includes: Prior to the interleaving (S704), the modulation order of the predefined modulation scheme is determined based on the transmission quality of the data transmission layer. .

13. The method (700) according to claim 11 or 12, characterized in that, The predefined modulation scheme defines the codeword bits of each column of the matrix (800). The mapping of tuples to the modulation symbols (810), and wherein the method (700) further includes: Determine each based on the transmission quality of the data transmission layer. The bit capacity of the codeword bits in a tuple; and Based on the determined bit capacity, determine: (i) the number of columns of the matrix (800) that will be arranged into the at least one first column group (802) and the at least one second column group (804). (ii) the correspondence between each data transmission layer in the data transmission layer and the at least one first column group (802) or the at least one second column group (804).

14. The method (700) according to claim 13, characterized in that, The method further includes performing the following operations before transmitting (S710) the mapped modulation symbol (512): The control message is generated, and the control message includes at least one of the following: The modulation order ; The codeword length ; The number of the at least one first column group (802) and the at least one second column group (804) used when interleaving the codeword bits ;as well as The correspondence between each data transmission layer in the data transmission layer and the at least one first column group (802) or the at least one second column group (804).

15. The method (700) according to claim 10, characterized in that, The codeword (510) is obtained using a linear code selected from one of turbo codes, systematic codes, systematic polar codes and low-density parity-check (LDPC) codes (200).

16. The method (700) according to claim 10, characterized in that, The predefined modulation scheme includes one of the following: Quadrature Amplitude Modulation (QAM), Phase Shift Keying (PSK), and Quadrature PSK (QPSK).

17. The method (700) according to claim 10, characterized in that, Also includes: In the case of Time Division Duplex (TDD) communication, the transmission quality of the data transmission layer is predetermined based on the uplink reference signal, or in the case of Frequency Division Duplex (FDD) communication, based on the downlink reference signal.

18. The method (700) according to claim 10, characterized in that, The data transmission layer includes a multiple-input multiple-output (MIMO) spatial layer.

19. A computer program product including a computer-readable storage medium, characterized in that, The computer-readable storage medium includes computer code that, when executed by at least one processor, causes the at least one processor to perform the method (700) according to any one of claims 10 to 18.

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