Dual Carrier Index Modulation (DC-IM)

Abstract

A method and technique for increasing data rates with high error performance in wireless transmission is described. A plurality of groups of p bits are obtained, where p is an integer greater than 1. A transmission signal is then generated. The generation of the transmission signal includes, for each group of p bits, dividing the group of p bits into a first subgroup of p1 bits and a second subgroup of p2 bits, where p1 and p2 are integers greater than 0. A modulation scheme sequence is then selected from a plurality of predetermined sequences of modulation schemes based on the p1 bits. The predetermined sequences are different from each other and each have a length R, where R is an integer greater than 1. The p2 bits are then mapped to R subcarriers according to the R modulation schemes of the selected sequence. Finally, the generated transmission signal is transmitted.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to communications, and in some particular embodiments, to techniques for transmission of signals using index modulation. [Background technology]

[0002] Wireless communication has been evolving for several decades now, and recently global communication systems as well as local network systems have been using technology based on Orthogonal Frequency Division Multiplexing (OFDM).

[0003] In OFDM, data symbols are transmitted simultaneously across multiple subcarriers. Data symbols here refer to modulation symbols that can carry one or several data bits depending on the modulation order. Simultaneously means within one OFDM symbol. OFDM symbols are obtained by mapping the modulation symbols to subcarriers of the transmission band and then transforming the subcarriers by an inverse Fourier transform (IFFT) or, in general, by an inverse orthogonal transform. OFDM symbols (here in the time domain) are then provided for transmission. Before transmission, further operations may be used, such as multiple-input multiple-output (MIMO) processing or any further signal processing related operations. This transmission may further include one or more of pulse shaping, amplification and modulation to a suitable carrier frequency.

[0004] A total of Nlog2M number of bits can be transmitted per OFDM symbol, where N and M are the number of subcarriers and modulation order in a resource unit (RU), respectively. A resource unit is a unit of allocatable resources. For example, the smallest allocatable resource unit may include multiple subcarriers in one or more OFDM symbols (corresponding to a time interval in the time domain). Here, the spectral efficiency of an OFDM system can be given by log2M. In the IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi) standards, such as IEEE.802.11ax (Wi-Fi6), various modulation and coding schemes (MCS) are defined with different modulation orders and coding rates. For example, MCS0 is a scheme with binary phase shift keying (BPSK) (M=2) and 1 / 2 coding rate. In MCS0, only log2M=1 bit can be transmitted per subcarrier. Therefore, this scheme may be used when the channel condition is poor or the received signal strength is low. To further improve reliability, dual carrier modulation (DCM) has been introduced, which modulates the same input bit onto a pair of subcarriers with the same or different constellations. However, one of the main drawbacks of DCM is that the data rate is reduced by half.

[0005] Increasing the data rate of methods such as DCM while still achieving high error performance is a challenging task. Summary of the Invention

[0006] Methods and techniques are described for enabling high data rates and error performance by using index modulation.

[0007] The invention is defined by the independent claims. Some exemplary implementations are presented in the dependent claims.

[0008] For example, a method for wireless transmission is provided, the method including: obtaining a plurality of groups of p bits, where p is an integer greater than 1; for the groups of p bits, (i) dividing the groups of p bits into a first subgroup of p1 bits and a second subgroup of p2 bits, where p1 and p2 are integers greater than 0; (ii) selecting a sequence of modulation schemes from a plurality of predetermined sequences of modulation schemes based on the p1 bits, where the predetermined sequences are different from one another, each of the predetermined sequences having a length R, where R is an integer greater than 1; and (iii) generating a transmission signal including mapping the p2 bits to R subcarriers, respectively, by the R modulation schemes of the selected sequence; and transmitting the generated transmission signal.

[0009] Further provided is a method for wireless reception, comprising the steps of receiving a transmission signal and obtaining from the received signal p=p1+p2 bits, where p1 and p2 are integers greater than 0, comprising determining a first subgroup of p1 bits and a second subgroup of p2 bits by performing maximum likelihood estimation on the received transmission signal, wherein (i) the p2 bits are mapped to R subcarriers, respectively, by R modulation schemes of a sequence of modulation schemes, where R is an integer greater than 1, and (ii) the sequence is one sequence of a plurality of predetermined sequences of modulation schemes, the predetermined sequences being different from each other, each of the predetermined sequences having a length R and indicating p1 bits.

[0010] According to one embodiment, a transmitting device is provided, comprising: a circuit configured to generate a transmission signal, the circuit comprising: obtaining a plurality of groups of p bits, where p is an integer greater than 1, and for each group of p bits, (i) dividing the group of p bits into a first subgroup of p1 bits and a second subgroup of p2 bits, where p1 and p2 are integers greater than 0, (ii) selecting a sequence of modulation schemes from a plurality of predetermined sequences of modulation schemes based on the p1 bits, where the predetermined sequences are different from each other, each of the predetermined sequences has a length R, where R is an integer greater than 1, and (iii) mapping the p2 bits to R subcarriers, respectively, according to the R modulation schemes of the selected sequence; and a transmitter configured to transmit the generated transmission signal.

[0011] According to one embodiment, a receiving device is provided, comprising: a receiver configured to receive a transmission signal; and a circuit configured to obtain from the received signal p=p1+p2 bits, where p1 and p2 are integers greater than 0, and determine a first subgroup of p1 bits and a second subgroup of p2 bits by performing maximum likelihood estimation on the received transmission signal, wherein the p2 bits are mapped to R subcarriers, respectively, by R modulation schemes of a sequence of modulation schemes, where R is an integer greater than 1, the sequence being one sequence of a plurality of predetermined sequences of modulation schemes, the predetermined sequences being different from each other, each of the predetermined sequences having a length R and representing p1 bits.

[0012] Such circuitry may be any circuitry, such as processing circuitry that includes one or more processors and / or other circuit elements.

[0013] These and other features and characteristics of the presently disclosed subject matter, as well as the method of operation and function of the associated elements of structure, and the combination of parts and economies of manufacture, will become more apparent from a consideration of the following description and appended claims, with reference to the accompanying drawings, all of which form a part of this specification. It is expressly understood, however, that each of the drawings is for illustrative and explanatory purposes only and is not intended as a definition of the limits of the disclosed subject matter. As used in the specification and claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0014] An understanding of the nature and advantages of various embodiments can be realized by reference to the following figures. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a block diagram illustrating a communication system. [Diagram 2] A schematic diagram showing mapping to resource units by DCM. [Figure 3a] FIG. 2 is a block diagram showing a transmitting device. [Figure 3b] FIG. 2 is a block diagram showing a receiving device. [Figure 4a] 4 is a flow chart illustrating exemplary steps performed by a transmitting device. [Figure 4b] 4 is a flow chart illustrating exemplary steps performed by a receiving device. [Diagram 5] FIG. 2 is a schematic diagram illustrating a mapping to resource units according to an example embodiment; [Figure 6] FIG. 1 is a schematic diagram showing BPSK and rotated BPSK constellations. [Figure 7] 11 is a graph illustrating simulation results showing bit error rate in an exemplary implementation. [Figure 8] 11 is a graph illustrating simulation results showing packet error rates in an exemplary implementation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] In accordance with certain exemplary implementations, like reference numbers and symbols in the various drawings indicate like elements.

[0017] For purposes of the following description, the terms "end", "top", "bottom", "right", "left", "vertical", "horizontal", "top", "bottom", "transverse", "longitudinal", and their derivatives are intended to refer to the disclosed subject matter as it is oriented in the respective figures. However, it should be understood that the disclosed subject matter can assume various alternative variations and step sequences, unless expressly specified to the contrary. It should also be understood that the specific devices and processes illustrated in the accompanying drawings and described in the following specification are merely exemplary embodiments or aspects of the disclosed subject matter. Thus, specific dimensions and other physical characteristics related to the embodiments or aspects disclosed herein should not be considered as limiting, unless otherwise specified.

[0018] As used herein, aspects, components, elements, structures, operations, steps, functions, instructions, and / or the like should not be construed as critical or essential unless expressly described as such. Also, as used herein, the articles "a" and "an" include one or more items and can be used interchangeably with "one or more" and "at least one." Furthermore, as used herein, the term "set" includes one or more items (e.g., related items, unrelated items, combinations of related and unrelated items, etc.) and can be used interchangeably with "one or more" or "at least one." When only one item is intended, the term "one" or similar language is used. Also, as used herein, terms such as "has," "have," "having," and the like are intended to be open-ended terms. Furthermore, the phrase "based on" is intended to mean "based at least in part on," unless expressly stated otherwise.

[0019] In Fig. 1, an exemplary communication system CS is shown, where Tx stands for a transmitter and Rx for a receiver. The transmitter Tx can transmit signals to the receiver Rx via an interface If. This interface may for example be a radio interface. This interface may be specified by resources available for transmission and reception by the transmitter Tx and the receiver Rx. Such resources may be defined in one or more (or all) of the time domain, the frequency domain, the code domain and the spatial domain. It should be noted that in general, a "transmitter" and a "receiver" may also both be integrated in the same device. That is, the devices Tx and Rx in Fig. 1 may include the functions of Rx and Tx, respectively.

[0020] The present disclosure is not limited to any particular transmitter Tx, receiver Rx, and / or interface If implementation. However, the present disclosure may be readily applied to a number of existing communication systems, as well as extensions of such systems or new communication systems. Exemplary existing communication systems may be, for example, 5G New Radio (NR) in current or future releases, and / or IEEE.802.11-based systems such as the recently researched IEEE.802.11be.

[0021] As explained in the background paragraph, OFDM is a wideband multi-carrier transmission technique that is quite widespread today and has been used in many standards, such as IEEE 802.11 (Wi-Fi), LTE (Long Term Evolution, the fourth generation (4G) mobile communication system), and New Radio (NR, which belongs to the fifth generation (5G)). In OFDM, the frequency band is divided into sub-bands, which are called subcarriers. Data symbols, obtained by mapping the input bits with a constellation, are transmitted simultaneously across these subcarriers. A certain number of subcarriers form a resource unit (RU). For example, an RU may contain 26, 52, 106, 242, 484 or 996 subcarriers. In Wi-Fi standards, such as IEEE 802.11ax (Wi-Fi 6), there are several MCSs that allow adjusting the data transfer rate and communication range. For example, MCS0 corresponds to BPSK with a coding rate of 1 / 2, which provides the most reliable communication and the lowest data rate of any MCS. To further extend the communication range and improve the error performance in Wi-Fi, at the expense of reducing the data rate by half, DCM has been introduced. It is noted that the present disclosure can be easily applied to OFDM systems, but is not limited thereto. It is believed that the present disclosure may be applied to other schemes in general, such as Frequency Division Multiplexing (FDM). OFDM or FDM is not limited to using FFT, but may use Discrete Fourier Transform (DFT) or other transforms. At the receiver side, a time domain signal is received. The samples belonging to the OFDM symbols are transformed by a (forward) transform, such as a Fast Fourier Transform. Thus, modulation symbols are obtained that are mapped to subcarriers, which are then demapped.

[0022] Dual Carrier Modulation (DCM) DCM is a modulation scheme that may be applied to OFDM-based transmission methods. DCM has been involved in the IEEE 802.11ax standard and is applied in MCS 0, 1, 3, and 4. In DCM, an RU with a size of N (e.g., N subcarriers) is divided into two parts.

[0023] FIG. 2 shows an exemplary mapping scheme for DCM-MCS0, ie, DCM based on BPSK.

[0024] As shown in Figure 2, the data symbols (x_n and x_m) of the first and second halves of an RU are determined by the same input bits to realize frequency diversity, where n ∈ {1,...,N / 2} and m = N / 2 + n are the subcarrier indexes of the first and second halves of an RU, respectively. It should be noted that the same or different modulation schemes can be used to map the input bits to the data symbols of the first and second halves of an RU. The term modulation here refers to mapping one or more bits to one signal point among multiple signal points given by a modulation scheme. The arrangement of signal points in a modulation scheme is also sometimes called a constellation. In the case of BPSK, one bit of data is mapped to one data symbol (modulation symbol). In BPSK, the two possible signal points are usually opposites and represent two phases that differ from each other by π (180°).

[0025] More specifically, according to DCM-MCS0, N / 2 groups of bits are respectively mapped to the first N / 2 subcarriers (e.g., the first N / 2 subcarriers when the subcarriers are ordered according to their index). Furthermore, the same N / 2 groups of bits are respectively mapped to the second N / 2 subcarriers (e.g., the last N / 2 subcarriers when the subcarriers are ordered according to their index). In this case, since BPSK mapping is applied, the size of the group is 1, which means that each of the N / 2 groups contains 1 bit. That is, N input bits are separated into two branches. In the first branch, N / 2 bits are mapped to data symbol x_n by the first BPSK mapping, while in the second branch, the remaining N / 2 bits are mapped to data symbol x_m by the second BPSK mapping.

[0026] DCM transmits the same information on two different subcarriers of OFDM, which makes communication more reliable and increases the communication range. However, for the same reason, the traditional DCM method halves the data rate of any MCS, which is a very important metric in wireless communication networks.

[0027] Data rate is one of the important indicators for efficiency in existing wireless communication networks. However, as the data rate increases in a system, the error performance usually deteriorates. As mentioned above, in Wi-Fi technologies such as IEEE.802.11ax, there are several MCSs to adjust the data rate and reliability. For example, MCS0 is the most reliable scheme, but its data rate is nevertheless low compared to schemes using higher layer modulation. DCM techniques can improve the reliability of MCSs and therefore also extend the communication range. However, this technique may reduce the data rate. In future wireless communication technologies that aim to achieve very high data rates, such as IEEE.802.11be, it would be desirable to avoid or reduce the reduction in data rate. Our invention overcomes this drawback of DCM while still achieving error performance close to that of DCM.

[0028] Embodiment 3a shows a transmitting device 350 according to some exemplary embodiments. The transmitting device 350 may be part of any wireless communication device, such as a STA or an AP, or may be a base station or a terminal in general. The transmitting device 350 comprises a memory 310, a processing circuit 320, and a wireless transceiver 330 (or a wireless transmitter 330), which may be able to communicate with each other via a bus 301. The transmitting device 350 may further comprise a user interface 340. However, in some applications, the user interface 340 is not necessary (e.g., some devices for machine-to-machine communication, etc.).

[0029] The memory 310 may store a number of firmware or software modules implementing some embodiments of the present disclosure. The memory 310 may be read by the processing circuitry 320, which may be configured to execute the firmware / software implementing the embodiments. The processing circuitry 320 may comprise one or more processors that, in operation, obtain a number of groups of p bits and generate a transmission signal. The generation of the transmission signal includes, for a group of p bits (or for each group of p bits among the number of groups of p bits), i) dividing the group of p bits into a first subgroup of p1 bits and a second subgroup of p2 bits, ii) selecting a sequence of modulation schemes from a number of predefined sequences of modulation schemes based on the p1 bits, the predefined sequences being different from one another, each of the predefined sequences having a length R, where R is an integer greater than 1, and iii) mapping the p2 bits to R subcarriers, respectively, according to the R modulation schemes of the selected sequence. In operation, the wireless transceiver 330 transmits the generated transmit signal.

[0030] Corresponding to the aforementioned transmitting device, a communication method for wireless transmission (one or more) performed by the transmitting device is provided. As shown in Fig. 4a, the method includes a step S420 of obtaining a plurality of groups of p bits. The method further includes a step S430 of generating a transmission signal, which includes for the group of p bits (or for each group of p bits among the plurality of groups of p bits), i) dividing the group of p bits into a first subgroup of p1 bits and a second subgroup of p2 bits (S440), ii) selecting a sequence of modulation schemes (MS) from a plurality of predetermined sequences of modulation schemes based on the p1 bits (S450), and iii) mapping the p2 bits to R subcarriers by R modulation schemes of the selected sequence, respectively (S460). Furthermore, the method includes a step S470 of transmitting the generated (S430) transmission signal. Furthermore, the method may include a step S410 of obtaining m bits. From this m bits, group(s) of p bits may then be obtained in step S420, as described below.

[0031] Generating the transmit signal (S430) may further include performing OFDM and / or further digital processing (such as MIMO), as well as analog processing (one or more of pulse shaping, power amplification, pre-distortion, modulation onto a system designated frequency carrier, etc.).

[0032] Group of bits It should be noted that in this disclosure, m and p are generally integers (or natural numbers) greater than 1, and p1 and p2 are integers greater than 0. It should be further noted that the terms "group of xxx bits" and "xxx bits" are used interchangeably and refer to a series of 0s and 1s having a length of "xxx". That is, a group of "xxx bits" may be composed of "xxx bits".

[0033] In general, p bits may be obtained from m bits. The m bits may be obtained, for example, from higher layers or from prior processing, which may include one or more of forward error correction coding, rate matching, interleaving, etc. These m bits may be divided (or separated) into groups of p bits according to some predefined pattern. For example, the first p bits of the m bits may be put into the first group of p bits, and so on (more specifically, the nth group of p bits should include the (n×p)+1th bit, the (n×p)×2th bit, ..., up to the (n+1)×pth bit of the m bits). In this disclosure, the number (count, amount) of groups of p bits is N p In general, the number (count) of groups of p bits (among multiple groups of p bits) is expressed as: TIFF0007606601000001.tif10149 In general, there may be one or more groups of p bits, i.e., a number N p is generally an integer greater than 0. That is, there may be one or more groups of p bits (i.e., N p ≧1).

[0034] Generating a transmit signal consists of N p It should be noted that the division, selection, and mapping may be performed for each of the groups. More specifically, the generation of the transmit signal may include dividing N p For each of the groups, the method may include: i) dividing the group of p bits into a first subgroup of p1 bits and a second subgroup of p2 bits; ii) selecting a sequence of modulation schemes from a plurality of predetermined sequences of modulation schemes based on the p1 bits; and iii) mapping the p2 bits to the R subcarriers, respectively, by the R modulation schemes of the selected sequence.

[0035] In particular, when separating, N p Each of the groups may be separated into equal numbers of p1 bits and p2 bits. p The first subgroups obtained by separating the groups may have the same size (number of bits), and N p The second subgroups obtained by separating the groups may have the same size (number of bits). However, the invention is not limited to this and generally can be used with N groups of p bits. p This group may be separated into subgroups of various sizes.

[0036] Furthermore, when selecting, N of p bits p For each of the N groups, the modulation scheme may be selected from a plurality of predetermined sequences of the same modulation scheme, but the invention is not limited thereto. p Each of the groups may have its own / corresponding multiple predefined sequences from which the modulation scheme is selected. p The groups have the same number A of mutually distinct predefined sequences from which the sequences are selected. p The predetermined sequences of the groups may have the same length R. p It is further noted that for each of the groups, the selection is based on a first subgroup of p1 bits obtained by separating the respective group of p bits.

[0037] Furthermore, when mapping, N p The p2 bits of each of the groups are generally mapped to R mutually distinct subcarriers. pEach of the second subgroups obtained by dividing the group may be mapped to the same number R of subcarriers. However, the number of these “N” subcarriers to which the second subgroups are mapped may be different. p ×R” subcarriers are generally different from each other. p It should further be noted that for each of the groups, mapping is performed using the sequence of modulation schemes selected in the group (based on the first subgroup of the group).

[0038] In this disclosure, the number (quantity, count) of subcarriers used per group (e.g., for each group) of p bits is denoted as R, and N p It is further noted that the number (quantity, count) of subcarriers used to transmit the groups is denoted as N. In general, R and N are integers greater than 1.

[0039] In general, m bits are divided into p bits. TIFF0007606601000002.tif10149 It should be noted that if m is greater than "N / R x p", then only the first "N / 2 x p" bits of the m bits may be grouped into N / R groups of p bits, and the remaining bits may be transmitted later. For example, if DCM (corresponding to R=2) is used, the m bits may be separated into N / 2 groups, each containing p bits.

[0040] The group of p bits may be separated or split into two groups, which in this disclosure are referred to as a first subgroup of p1 bits and a second subgroup of p2 bits, respectively. For example, each of the p bits may be placed into either the first subgroup or the second subgroup according to a predetermined or predefined pattern (known to both the receiver and the transmitter). Thus, the sum of p1 and p2 may be p=p1+p2. For example, the first p1 of the p bits may be placed into the first subgroup, and the last p2 of the p bits may be placed into the second subgroup.

[0041] Predefined sequence or mode activation pattern (MAP) It should be noted that in this disclosure, the number (quantity, count) of predefined sequences is referred to as A, and the number (quantity, count) of mutually distinct modulation schemes that appear in the predefined sequences (e.g., in all predefined sequences combined) is referred to as Q. Furthermore, it should be noted that the terms "predefined sequences" and "mode activation patterns" are used interchangeably.

[0042] In general, the predetermined sequences may have the same length R, where R is an integer greater than 1. That is, each predetermined sequence may have the same number of elements (i.e., modulation schemes). Note that in general, the length of the predetermined sequence and the number of subcarriers to which the group is mapped may be the same.

[0043] In general, the predetermined sequences may be different from each other. For example, in some embodiments, the Hamming distance between any two of the predetermined sequences may be R. This may be written as follows: If k ≠ l, then d(I k ,I l )=R. where k∈{1,2,....,Q}, l∈{1,2,....,Q}, d(v,z) is the Hamming distance between v and z, and I k and I l are two predefined sequences.

[0044] That is, in some embodiments, for each pair of different predefined sequences, the Hamming distance is equal to the length of the sequences, i.e., any two sequences differ at each position.

[0045] Here, the Hamming distance between two sequences of modulation schemes is the number of positions (first position, second position, ...., last position in the sequence) where the corresponding modulation schemes differ. That is, the Hamming distance between the first sequence and the second sequence is the number of positions where the modulation scheme of the first sequence differs from the modulation scheme of the second sequence. More specifically, the first, second, ...., and last modulation schemes of the first sequence are compared with the first, second, ...., and last modulation schemes of the second sequence, respectively.

[0046] However, the singleton limit (A ≤ Q R-d+1 ), it may only be possible to generate at most A=Q different MAPs from the Q different modes with Hamming distance R. Accordingly, in some embodiments, the number A of predefined sequences is smaller than or equal to the number Q of mutually distinct modulation schemes appearing in the predefined sequences.

[0047] In some embodiments (especially when using DCM), each of the predetermined sequences has a length R=2. That is, when DCM is applied on two subcarriers, the length of one / each MAP may be 2 (i.e., the diversity order is 2). Furthermore, in some embodiments with R=2, the Hamming distance between any two sequences is 2. That is, in some embodiments, for any k≠l, the condition d(I k ,I l )=2 is satisfied.

[0048] In some embodiments, a predetermined sequence I k (1≦k≦A≦Q) are TIFF0007606601000003.tif10149 where x i (1≦i≦Q) are Q mutually distinct modulation schemes, and π j (1≦j≦R) is a permutation (e.g., a repermutation) of R of {1,2,....,Q}.

[0049] For example, Q MAPs with Hamming distance R may be given by the following equation (1≦k≦Q): I k ={X k ,X k ,...,X k} TIFF0007606601000004.tif7149 By introducing TIFF0007606601000005.tif8149 teeth, TIFF0007606601000006.tif8149 In the corresponding predetermined sequence TIFF0007606601000007.tif9149 represents the mode index of the k = {k,k,...,k}. Another example for Q MAPs with Hamming distance R is I k =(k,k+1,...,Q,1,2...,Q,1,2...,R) It is given by the above formula.

[0050] Furthermore, in some implementations with R=2 (DCM), the achievable MAP is I a = (a, b), where a ∈ {1,...,Q}, b=-(a mod(-(Q+1))=-a mod(Q+1)=Q+1-a.

[0051] Modulation method (also called mode or constellation) In general, each modulation scheme X that appears in a predefined sequence k Each modulation scheme X has the same number (quantity, count) of M symbols. k is a set of symbols of size M. Furthermore, the Q distinct modulation schemes may be symbol-disjoint, i.e., no symbol appears in more than one of the Q distinct modulation schemes. This means that for all k≠l, X k ∩X l = φ, k ∈ {1, ..., Q}, l ∈ {1, ..., Q}. Using non-overlapping modes may allow easy detection by the receiver (e.g., by its circuitry) of the mode of the modulation scheme selected by the transmitter (e.g., by its circuitry).

[0052] In some embodiments, the modulation formats appearing in the predetermined sequence can be obtained by partitioning a Phase Shift Keying (PSK) or Quadrature Amplitude Modulation (QAM) format into groups having M symbols and / or are interrelated by a rotation in the complex plane.

[0053] For example, modulation schemes (or modes) include binary phase shift keying (BPSK) and quadrature binary phase shift keying (QBPSK), which are shown in Figure 6. That is, the two modes in the BPSK constellation can be obtained by the original BPSK symbol and its rotated version as X1 = {1, -1} and X2 = {j, -j}, respectively, where j is the imaginary unit, i.e., J 2=-1). That is, the symbols of the first modulation scheme may be the BPSK symbols {1,-1}, and the symbols of the second modulation scheme may be obtained by rotating the BPSK symbols by π / 2 on the complex plane. The symbols of the first and second modulation schemes may be obtained by dividing the QPSK symbols (or, more generally, the symbols of a modulation scheme having four symbols) into two groups, each of which corresponds to one of the first and second modulation schemes. For example, the first BPSK mapping maps 0 and 1 to phases 0 and π, and the second BPSK mapping maps 0 and 1 to phases π / 2 and 3π / 2, which correspond to the two aforementioned BPSK constellations. It should be noted that the QPSK and the corresponding two BPSK mappings may be rotated by a constant and the same angle, for example π / 4. Then the first BPSK mapping maps 0 and 1 to phases π / 2 and 5π / 2, and the second BPSK mapping maps 0 and 1 to phases 3π / 2 and 7π / 2. These were examples of how to get two modulation schemes (Q=2), each with two symbols (M=2).

[0054] For example, in the case of MCS0, two modes may be defined as shown in Figure 6, and d(I 1 ,I 2 ) = d(I1,I2) = 2 to preserve frequency diversity. 1 =(1,2) and I 2 = (2,1). Thus, in this example, the MAP can be chosen to transmit a total of p1 = 1 bits on each pair of subcarriers, which may make it possible to compensate for the data rate loss caused by transmitting each group of p2 = 1 bits over each of two subcarriers.

[0055] In general (i.e., when Q≧2 and M≧2), Q modulation schemes may be obtained by partitioning the constellation by at least “Q×M” symbols. For example, the symbols of 16QAM may be divided into 4 groups with 4 symbols each, 8 groups with 2 symbols each, or 2 groups with 8 symbols each. This is not limited to 16QAM. For example, the symbols of any QAM (4QAM, 8QAM, 16QAM, 32QAM, 64QAM, 256QAM, etc.) or PSK modulation (4PSK, 8PSK, 16PSK, ...) may be partitioned.

[0056] Alternatively, a new modulation scheme can be obtained from a given modulation scheme by rotating the constellation in the complex plane (e.g., by rotating each symbol), such that the given modulation scheme and the rotated modulation scheme have the same number of symbols.

[0057] In general, any constellation, in particular any QAM and any PSK modulation, can be rotated to obtain (additional) modulation schemes. However, it is not possible to obtain (additional) modulation schemes X by rotating a given constellation. k When we obtain (k∈{1,...,Q}), for all k≠l, X k ∩X l = φ, (k ∈ {1, ..., Q}, l ∈ {1, ..., Q})

[0058] Select MAP(s) For each group of p bits, a selection of the MAP(s) is performed based on respective p1 bits, the p1 bits being obtained by dividing the respective group of p bits into a first and a second subgroup. In particular, said selection may be performed based on the values ​​of said p1 bits. In some embodiments, the values ​​of the p1 bits determine which MAP is selected.

[0059] In general, each of the MAPs may correspond to or be associated with a (single) combination of possible values ​​of the p1 bits. That is, each MAP may indicate a corresponding value (e.g., a value indicating 0 or 1) for each of the p1 bits. In particular, when making the selection, the MAP corresponding to the p1 bits may be selected. The association between the MAP and the values ​​of the p1 bits may be predefined or known to both the sender and the receiver. Thus, the selection of the MAP, i.e., which MAP is chosen, indicates the values ​​of the p1 bits. Thus, at the receiver, the values ​​of the p1 bits can be determined from the MAP to be used.

[0060] In particular, in some embodiments, the first subgroup is of p1=log2A bits, i.e. the second group comprises or consists of p1=log2A bits. In these embodiments, there is a one-to-one correspondence between the MAP of the plurality of MAPs from which a MAP is selected and the possible values ​​of the p1 bits.

[0061] By selecting a MAP to indicate a second subgroup of bits, the data rate can be increased and still allow good error correction. For example, having at least M different MAPs (e.g., having a Q equal to or greater than M) may overcome / compensate for the drawback of the halved data rate due to the use of DCM. In particular, compared to DCM, the mapping scheme (or constellation) used for a pair of subcarriers (with R=2) is selected according to one or more additional input bits. Thus, by applying index modulation (IM) to the constellation mode, the data rate of DCM can be increased while still achieving reliable communication with outstanding error performance. For example, for R=Q=A=2, it may be possible to transmit one additional bit per pair of subcarriers compared to DCM-MCS0. Furthermore, especially for R=2, this allows the use of the established DCM architecture already used in the IEEE 802.11ax wireless standard.

[0062] Mapping of second subgroup(s) to symbols / subcarriers In general, N of p bits pFor each of the groups, p2 bits are mapped to R data symbols. This mapping may be performed according to a MAP selected based on p1 bits of this group of p bits. Here, each of the R data symbols can be obtained by using one (e.g., a single) of the R modulation schemes of the selected MAP to map the p2 bits. Thus, the R data symbols may correspond to the p2 bits respectively according to the R modulation schemes of the selected MAP. That is, for each modulation scheme appearing in the selected MAP, the p2 bits are mapped to a symbol corresponding to the p2 bits according to the modulation scheme. This gives a series of R symbols, each of which represents p2 bits. Since each of the modulation schemes has M symbols, the second subgroup may include or consist of p2=log2M bits.

[0063] Furthermore, N of p bits p For each of the groups, R data symbols obtained by mapping the p1 bits of this group to symbols may be mapped to the R subcarriers, respectively. In particular, in some embodiments (especially in embodiments where the predetermined sequence has a length R=2), the p1 bits of each group of p bits are mapped to two subcarriers. In general, N p For each of the groups, the R subcarriers onto which the R data symbols will be mapped may be predefined or predetermined (e.g., configured by higher layer signaling) and may be specifically known to the receiver. pFor each nth group of the groups, the R subcarriers are subcarriers with indices n, n+N / R, n+2N / R, ..., n+(R-1)N / R. That is, the R subcarriers onto which the R symbols of the nth group are mapped may be subcarriers with indices n, n+N / R, n+2N / R, ..., n+(R-1)N / R.

[0064] More specifically, a predetermined sequence is generated based on the values ​​of p1 bits. TIFF0007606601000008.tif9149 After selecting, this selected predefined sequence I n R modulation schemes TIFF0007606601000009.tif9149 , TIFF0007606601000010.tif9149 , ..., TIFF0007606601000011.tif11149 , p2 bits of the nth group of p bits are used to represent R data symbols TIFF0007606601000012.tif8149 , TIFF0007606601000013.tif8149 , ..., TIFF0007606601000014.tif9149 In particular, the same p2 bits of the nth group may be mapped to each of the R data symbols, where TIFF0007606601000015.tif8149 is the index of the i-th subcarrier used to transmit the n-th group of symbols, which may be used to distinguish the R data symbols of the various groups of p bits.

[0065] The mapping may be performed according to a selected MAP, i.e., the order of the R modulation schemes in the MAP may determine which of the R acquired data symbols are mapped to which of the R subcarriers. For example, the symbols acquired by using a first modulation scheme (MS) of the MAP may be mapped to the subcarrier with the lowest index among the R subcarrier indices, the symbols acquired by using a second MS may be mapped to the subcarrier with the second lowest index among the R subcarriers, and so on.

[0066] In general, after determining the MAP(s), the same processing as in DCM may be performed. This is illustrated in FIG. 5, which shows an example mapping. As illustrated in FIG. 5, there are N / 2 groups of p bits (only the first group and the N / 2th group are explicitly illustrated, the other groups are shown as dots). Each group of p bits (more specifically, p2 bits of each group) is mapped to 2 (R=2) subcarriers. That is, an RU may be formed by mapping p2 bits of each of the N / 2 groups of p bits to 2 (R=2) subcarriers.

[0067] More specifically, p2 bits of the nth group of p bits are TIFF0007606601000016.tif7149 where (·) T For this purpose, we use a modulation scheme with a MAP selected based on the p1 bits of the nth group (in Figure 5, this selected MAP is I n In particular, the first data symbol TIFF0007606601000017.tif8149 may be obtained using a first modulation scheme of the MAP, and a second data symbol TIFF0007606601000018.tif7149 may be obtained using the second modulation scheme of the MAP, i.e., by mapping the same p2 bits using the first and second modulation schemes of the selected MAP, respectively, the data symbol TIFF0007606601000019.tif8149 and TIFF0007606601000020.tif7149 is obtained.

[0068] For example, p1 bits of the nth group of p bits are TIFF0007606601000021.tif6149 where n=1,...,N / 2; TIFF0007606601000022.tif7149 and TIFF0007606601000023.tif7149 represent the mode index utilized across the n-th and m-th subcarriers, respectively. Therefore, MAP I n After determining / selecting, the p2 bits of the nth group are assigned to the mode (constellation) TIFF0007606601000024.tif7149 and TIFF0007606601000025.tif7149 Use the data symbol TIFF0007606601000026.tif8149 and TIFF0007606601000027.tif7149 is mapped to.

[0069] In the example shown in FIG. 5, the data symbol obtained by mapping p2 bits of the nth group is TIFF0007606601000028.tif8149 , TIFF0007606601000029.tif7149 are arranged in resource units (RUs) with indices n and m=n+N / 2, respectively. That is, the data symbols TIFF0007606601000030.tif8149 , TIFF0007606601000031.tif7149 are mapped to subcarriers with indexes n and m=n+N / 2, respectively. An RU may be constructed by performing this process for all n=N / 2 groups of p bits.

[0070] 3b illustrates a receiving device 355 according to some example embodiments. The receiving device 355 includes a memory 315, a processing circuit 325, and a wireless transceiver 335 (or wireless receiver 335), which may be able to communicate with each other via a bus 306. The receiving device 355 may further include a user interface 345. However, in some applications, this user interface 345 is not required (e.g., some devices for machine-to-machine communication, etc.).

[0071] The transceiver / receiver 335 operates to receive a transmission signal. The processing circuit 325 may include one or more processors, which operates to obtain p=p1+p2 bits from the received transmission signal, where p1 and p2 are integers greater than zero. The obtaining includes determining a first subgroup of p1 bits and a second subgroup of p2 bits by performing maximum likelihood estimation on the received transmission signal. The p2 bits are respectively mapped to R subcarriers by R modulation schemes of a sequence of modulation schemes (e.g., mapped by a transmitting device that transmitted the received signal). Furthermore, R is an integer greater than 1, and the sequence is one sequence of a plurality of predetermined sequences of modulation schemes. Furthermore, the predetermined sequences are different from each other, and each of the predetermined sequences has a length R and indicates p1 bits.

[0072] Corresponding to the above receiving device, a communication method for wireless reception is provided which is executed by the receiving device. As shown in Fig. 4b, the method includes a step of receiving a transmission signal (S415). The method further includes a step of obtaining p=p1+p2 bits from the received transmission signal (S425), where p1 and p2 are integers greater than 0. As further shown in Fig. 4b, the step of obtaining p bits (S425) includes a step of obtaining N of the p bits. p It should be noted that a step of obtaining (S425) may be performed for each of the groups. This step of obtaining (S425) includes a step of determining (S435) a first subgroup of p1 bits and a second subgroup of p2 bits by performing (S445) a maximum likelihood estimation on the received transmission signal. More specifically, by performing (S445) a detection / estimation of ML, MAP TIFF0007606601000032.tif7149 and symbol TIFF0007606601000033.tif6149 may be determined or estimated, where the superscript "n" is the index of the group of p bits for which step (S425) is currently being performed. In general, ML detection / estimation is performed based on the received signal. For example, ML detection may be performed based on the symbols Y n It may be based on the symbol TIFF0007606601000034.tif6149 Note that p may include a symbol for each of the R subcarriers. Thus, by ML detection, a symbol may be estimated / determined for each of the R subcarriers associated with each group of p bits.

[0073] The MAP determined in the detection of ML is one of A predetermined MAPs I k It is further noted that the predetermined MAPs are one of the following: As already mentioned above, these predefined MAPs may be known to the transmitter and receiver (e.g., they may be defined in a standard or configured by higher layer signaling).

[0074] Further, the step of acquiring (S435) includes acquiring the number of predetermined MAPs from the MAP (for example, A number of predetermined MAPs I k (2≦k≦A) to MAP TIFF0007606601000035.tif7149 The obtaining step (S435) may further include a step of determining p1 bits (S455) from the determined symbols (from selecting p2 bits). Further, the obtaining step (S435) may include a step of determining p2 bits (S465) from the determined symbols, as will be further described below.

[0075] As described above, the p2 bits are respectively mapped to R subcarriers by R modulation schemes among a sequence of modulation schemes (e.g., mapped by a transmitting device that transmitted the received signal). The sequence is one of a plurality of predetermined sequences of modulation schemes. Furthermore, the predetermined sequences are different from each other, each of the predetermined sequences has a length R and indicates p1 bits. More specifically, each predetermined sequence indicates one combination of values ​​of the p1 bits. That is, each predetermined sequence indicates a corresponding value (e.g., a value indicating 0 or 1) for each of the p1 bits.

[0076] At the receiver, after performing a Fast Fourier Transform (FFT), the received signals at subcarriers n and m=n+N / 2 (for R=2 subcarriers) can be given by: TIFF0007606601000036.tif7149 TIFF0007606601000037.tif6149 Here, h n and h m are the channel fading coefficients for subcarriers n and m, respectively, and w n and w m represents the noise sample in the frequency domain. Using the maximum likelihood (ML) detection rule, i) N p MAP selected based on p1 bits of the nth group out of p groups TIFF0007606601000038.tif7149 and ii) the MAP TIFF0007606601000039.tif7149 When using the n-th group of p2 bits, the data symbol TIFF0007606601000040.tif6149 can be obtained according to the following formula (S445): TIFF0007606601000041.tif9149 Now, suppose that R=2 and the nth group uses subcarriers with index n and m=n+N / 2, then Y n =[y n ,y m ] T , H n =diag(h n ,h m ) T ), where diag(·) represents the diagonalization operation, as previously mentioned. TIFF0007606601000042.tif7149 is the data symbol TIFF0007606601000043.tif8149 and TIFF0007606601000044.tif7149 Includes.

[0077] In general, (R≧2 and N p any mapping pattern to subcarriers of groups TIFF0007606601000045.tif9149 , TIFF0007606601000046.tif11149 , TIFF0007606601000047.tif12149 , and TIFF0007606601000048.tif10149 where: TIFF0007606601000049.tif8149 is the index of the i-th subcarrier used to transmit the n-th group of symbols, TIFF0007606601000050.tif11149 is the index TIFF0007606601000051.tif8149 is the signal received on the subcarrier having

[0078] For example, MAP TIFF0007606601000052.tif7149 and symbol TIFF0007606601000053.tif6149 The joint decision of TIFF0007606601000054.tif10149 where each X k MAP TIFF0007606601000055.tif10149 This includes any sequence of symbols that corresponds to (or is consistent with)

[0079] Mathematically, this TIFF0007606601000056.tif9149 MAP I k are different from each other, and various modulation methods X i Since there is no common symbol in (1≦i≦Q), each X n X k MAP I k and a set of symbol sequences X k Therefore, the MAP TIFF0007606601000057.tif7149 is based on ML detection. TIFF0007606601000058.tif6149 A set of symbol sequences X, including k MAP I k It may be determined as:

[0080] That is, diag(v) is a diagonal matrix (i.e., a matrix with zeros outside its diagonal elements) with diagonal elements corresponding to each element of vector v. The receiver typically receives (one or more) MAP TIFF0007606601000059.tif7149 and symbols TIFF0007606601000060.tif6149 It should be noted that a receiver (e.g., its processing circuitry) may perform joint ML detection with the MAP(s) to be used by the transmitter, but the present invention is not limited thereto. For example, the receiver (e.g., its processing circuitry) may first perform ML detection to determine the MAP(s) to be used by the transmitter, and after the MAP(s) are determined, the determined MAP(s) may be used. TIFF0007606601000061.tif7149 may be used to perform ML detection of the symbols.

[0081] In step S455, the determined MAP determined by ML detection (S435) is TIFF0007606601000062.tif7149 From the p1 bits, p1 bits may be determined. More specifically, A predetermined MAP I k From (2≦k≦A), MAP TIFF0007606601000063.tif7149 The p1 bits may be determined based on selecting A, i.e., the p1 bits may be determined based on which of the A predefined MAPs has been determined / detected by the ML detection means.

[0082] In particular, each of the A predefined MAPs may be associated with or correspond to a particular combination (e.g., a single combination) of values ​​of the p1 bits. These associations between the predefined MAPs and the combinations of values ​​may be known to the transmitter and receiver (e.g., they may be defined in a standard or configured by higher layer signaling). Thus, in step S455, the p1 bits are associated with or correspond to the detected MAPs. TIFF0007606601000064.tif7149 It can be determined that the metric has a value corresponding to:

[0083] That is, at the receiver, p1 bits of a group of p bits can be determined as follows: ML detection may be performed to determine the MAP used to map the p2 bits to the R symbols. In particular, for each group of p bits, the corresponding R subcarriers onto which the p2 bits are respectively mapped may be known to the receiver. For example, the corresponding R subcarriers may be predefined (e.g., in a standard) or may be signaled / indicated by the transmitter (e.g., by higher layer signaling). Thus, the receiver may detect the received symbol Y on the R subcarriers as n Regarding which of the predetermined MAPs (i.e., which I n ), we may determine how to minimize the "argmin" expression above. For example, TIFF0007606601000065.tif6149 It may be determined which of the predetermined MAPs corresponds to the MAP.

[0084] Furthermore, in step S465, the symbol determined by the ML detection is TIFF0007606601000066.tif6149 p bits may be determined based on or according to the R determined symbols. TIFF0007606601000067.tif10149 , TIFF0007606601000068.tif11149 , ..., TIFF0007606601000069.tif11149 Each of the R determined symbols generally corresponds to a particular combination (e.g., a single combination) of values ​​of the p bits, i.e., each of the R determined symbols can indicate a corresponding value (e.g., a value indicating 0 or 1) for each of the p bits.

[0085] Therefore, in step S465, p2 bits are added to the detected symbol TIFF0007606601000070.tif6149 Since the transmitter maps p2 bits to each of the R subcarriers, the values ​​of the p2 bits may generally correspond to each of the detected symbols. TIFF0007606601000071.tif10149 , TIFF0007606601000072.tif11149 , ..., TIFF0007606601000073.tif11149 does not correspond to the same value of the p2 bits (e.g., due to an imperfect channel), then, for example, the p2 bits are more likely to represent the determined symbol than any other combination of the p2 bits. TIFF0007606601000074.tif6149 , . . . , or more.

[0086] Experimental Results / Advantages of the Invention The method previously described with reference to Fig. 5 (denoted DCIM-MCS0, where E stands for enhanced) achieves only slightly worse error performance than DCM-MCS0 described with reference to Fig. 2 while doubling the data rate, as can be seen in Fig. 7. Simulation results in terms of bit error rate (BER) in a Rayleigh channel without additional coding are shown in Fig. 7. The spectral efficiency of DCM-MCS0 is 1 / 2 log22 = 0.5 bps / Hz, while the spectral efficiency of the proposed method is log22 = 1 bps / Hz. As can be seen, DCIM-MCS0 can achieve twice the spectral efficiency and still achieve outstanding error performance. Here, SNR is the ratio of SNR to E B This refers to the signal-to-noise ratio per bit, defined as E B is the signal energy per bit and N0 is the noise spectral density.

[0087] FIG. 8 shows the results of a simulation of the packet error rate (PER) performance of MCS0, DCM-MCS0, and the exemplary implementation described in connection with FIG. 5. The channel model used in the simulation was channel model B with coding, specifically convolutional coding (CC) with a coding rate of 1 / 2. Furthermore, in this simulation, one packet contains 960 bytes of information. As can be seen from the simulation results, DCIM-MCS0 achieves much better error performance while achieving the same data rate as MCS0. Furthermore, the simulation results show that the error performance of DCM-MCS0 and DCIM-MCS0 are quite close, and DCIM achieves much higher spectral efficiency than DCM-MCS0. As in FIG. 7, the SNR is proportional to the E per bit. B / N0 is defined as

[0088] As can be seen from the above description, some embodiments of the present disclosure can provide a relatively simple structure for mapping modulation symbols to respective frequencies.

[0089] Furthermore, the present disclosure is not limited to selecting two modulation schemes: some embodiments may utilize more than two modulation schemes, thus providing more flexibility for mode selection.

[0090] In some embodiments, the processing circuitry performing the functions described herein may be integrated in an integrated circuit on a single chip. The output of the processing circuitry is a composite signal in the time domain. This may be a discrete signal that the processing circuitry can provide to the transceiver 330 for transmission. The processing circuitry may also implement a control function for controlling the transceiver 330 to transmit the signal. The transceiver 330 is configured (e.g., by the processing circuitry) to transmit the signal by the symbols carrying the generated signal. For example, the processing circuitry 320 may configure (control) the transceiver 330 to transmit the signal via the bus 301. The transceiver may be, for example. a wireless transceiver.

[0091] As mentioned above, the program code can enable a processing circuit (e.g., comprising one or more processors) to operate as a special-purpose computer programmed to execute the techniques disclosed herein. In FIG. 3a, the memory 310 is shown as being separate from the processing circuit. However, this is only an example. In general, the memory 310 may be implemented within the processing circuit, e.g., within one or more processors. The term "memory" refers to any type of long-term, short-term, volatile, non-volatile, or other memory, and is not limited to any particular type or number of memories, or the type of medium on which the memory is stored.

[0092] Software and hardware implementation The methodologies described herein (at the transmitter side and the receiver side) may be implemented by various means, depending on the application. For example, these methodologies may be implemented in hardware, an operation system, firmware, software, or any combination of two or all of these. A hardware implementation may use any processing circuit, which may comprise one or more processors. For example, the hardware may comprise one or more of an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processor (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, any electronic device, or other electronic circuit unit or element designed to perform the functions described above.

[0093] When implemented as program code, the functions performed by the transmitting device (apparatus) may be stored as one or more instructions or codes in a non-transitory computer-readable storage medium, such as memory 310 or any other type of storage device. A computer-readable medium comprises a physical computer storage medium, which may be any available medium accessible by a computer, or generally by the processing circuitry 320. Such computer-readable medium may comprise RAM, ROM, EEPROM, optical disk storage, magnetic disk storage, semiconductor storage, or other storage devices. Specific, non-limiting examples include compact discs (CDs), CD-ROMs, laser discs, optical discs, digital versatile discs (DVDs), Blu-ray discs (BDs), and the like. Combinations of various storage media may also be realized, i.e., distributed and heterogeneous storage devices may be utilized.

[0094] The above-mentioned embodiments and exemplary implementations are provided as non-limiting examples. It is understood that various modifications may be made without departing from the claimed subject matter. For example, modifications may be made to adapt each example to new systems and situations without departing from the central ideas described herein. In particular, the above-mentioned embodiments and exemplary implementations are multiple-input / multiple-output (MIMO) compatible and can be applied to any MCS.

[0095] Selected embodiments and examples In summary, a method and technique for increasing data rates with high error performance in wireless transmission is described. A plurality of groups of p bits are obtained, where p is an integer greater than 1. Furthermore, a transmission signal is generated. The generation of the transmission signal includes, for the group of p bits, dividing the group of p bits into a first subgroup of p1 bits and a second subgroup of p2 bits, where p1 and p2 are integers greater than 0. Furthermore, a sequence of modulation schemes is selected from a plurality of predetermined sequences of modulation schemes based on the p1 bits. The predetermined sequences are different from each other, and each of the predetermined sequences has a length R, where R is an integer greater than 1. Furthermore, the p2 bits are mapped to R subcarriers respectively according to the R modulation schemes of the selected sequence. Finally, the generated transmission signal is transmitted.

[0096] A method for wireless transmission is provided, the method including: i) obtaining a plurality of groups of p bits, where p is an integer greater than 1; ii) for the group of p bits, dividing the group of p bits into a first sub-group of p1 bits and a second sub-group of p2 bits, where p1 and p2 are integers greater than 0; selecting a sequence of modulation schemes from a plurality of predetermined sequences of modulation schemes based on the p1 bits, the predetermined sequences being different from one another, each of the predetermined sequences having a length R, where R is an integer greater than 1; and generating a transmission signal including mapping the p2 bits to R subcarriers, respectively, by the R modulation schemes of the selected sequence; and iii) transmitting the generated transmission signal.

[0097] In some embodiments, each of the predetermined sequences has a length R=2.

[0098] In some embodiments, the first subgroup is of p1=log2A bits, where A is the number of a predetermined sequence, and each modulation scheme appearing in the predetermined sequence has the same number M of symbols, and the second subgroup is of p2=log2M bits.

[0099] In some embodiments, the Hamming distance between any two of the predetermined sequences is R and / or the number A of the predetermined sequences is less than or equal to the number Q of mutually distinct modulation schemes appearing in the predetermined sequences.

[0100] For example, a predetermined sequence I k (1≦k≦A≦Q) are TIFF0007606601000075.tif10149 where X i(1≦i≦Q) are Q mutually distinct modulation schemes, and π j (1≦j≦R) is a sequence of R permutations of {1,2,....,Q}.

[0101] In some embodiments, the modulation schemes appearing in the predetermined sequence can be obtained by partitioning a phase shift keying or quadrature amplitude modulation scheme into groups having M symbols and / or are interrelated by a rotation in the complex plane.

[0102] For example, modulation schemes include binary phase shift keying (BPSK) and quadrature binary phase shift keying (QBPSK).

[0103] In some embodiments, the number of groups of p bits is TIFF0007606601000076.tif12149 where N is the Nth number of p bits. p is the number of subcarriers used to transmit the p groups, and / or the generation of the transmit signal is p For each of the groups, it involves splitting, selecting, and mapping.

[0104] In some embodiments, N p For each nth group of the groups, the R subcarriers are the subcarriers with indices n, n+N / R, n+2N / R, . . . , n+(R-1)N / R.

[0105] A method for wireless reception is provided, comprising the steps of: i) receiving a transmission signal; and ii) obtaining from the received signal p=p1+p2 bits, where p1 and p2 are integers greater than 0, comprising determining a first subgroup of p1 bits and a second subgroup of p2 bits by performing maximum likelihood estimation on the received transmission signal, wherein the p2 bits are mapped to R subcarriers, respectively, by R modulation schemes of a sequence of modulation schemes, R being an integer greater than 1, the sequence being one sequence of a plurality of predetermined sequences of modulation schemes, the predetermined sequences being different from each other, each of the predetermined sequences having a length R and indicating p1 bits.

[0106] In some embodiments, each of the plurality of predetermined sequences has a length R=2.

[0107] In some embodiments, the first subgroup is of p1=log2A bits, where A is the number of a predetermined sequence, and each modulation scheme appearing in the predetermined sequence has the same number M of symbols, and the second subgroup is of p2=log2M bits.

[0108] In some embodiments, the Hamming distance between any two of the predetermined sequences is R and / or the number A of the predetermined sequences is less than or equal to the number Q of mutually distinct modulation schemes appearing in the predetermined sequences.

[0109] A transmitting apparatus is provided, comprising: a circuit configured to generate a transmission signal, the circuit comprising: i) obtaining a plurality of groups of p bits, where p is an integer greater than 1; ii) for each group of p bits, dividing the group of p bits into a first subgroup of p1 bits and a second subgroup of p2 bits, where p1 and p2 are integers greater than 0; selecting a sequence of modulation schemes from a plurality of predetermined sequences of modulation schemes based on the p1 bits, the predetermined sequences being different from one another, each of the predetermined sequences having a length R, where R is an integer greater than 1; and iii) mapping the p2 bits to R subcarriers, respectively, by the R modulation schemes of the selected sequence. The transmitting apparatus further comprises a transmitter configured to transmit the generated transmission signal.

[0110] A receiving device is provided, comprising a receiver configured to receive a transmission signal, further comprising a circuit configured to: obtain p=p1+p2 bits from the received signal, where p1 and p2 are integers greater than 0, and determine a first subgroup of p1 bits and a second subgroup of p2 bits by performing a maximum likelihood estimation on the received transmission signal, where the p2 bits are mapped to R subcarriers, respectively, by R modulation schemes of a sequence of modulation schemes, where R is an integer greater than 1, the sequence being one sequence of a plurality of predetermined sequences of modulation schemes, the predetermined sequences being different from each other, each of the predetermined sequences having a length R and representing the p1 bits.

[0111] Further, a computer program is provided which, when stored on a non-transitory medium and executed by a computer or processing circuit, comprises code instructions for performing the steps of any of the methods described above.

[0112] According to some embodiments, the processing circuitry and / or the transceiver are incorporated in an integrated circuit (IC).

[0113] While the disclosed subject matter has been described in detail for purposes of illustration based on what are currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is for this purpose only and that the disclosed subject matter is not limited to the disclosed embodiments, but rather is intended to cover modifications and equivalent arrangements within the spirit and scope of the appended claims. For example, it is to be understood that the subject matter disclosed herein contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.

Claims

1. 1. A method for wireless transmission, comprising: obtaining a plurality of groups of p bits, where p is an integer greater than 1; For a group of p bits, (i) dividing said group of p bits into p １ A first subgroup of bits and p ２ and a second subgroup of p bits, １ and p ２ is an integer greater than 0; (ii) the p １ selecting a sequence of modulation schemes from a plurality of predetermined sequences of modulation schemes based on the bits; the predetermined sequences are different from one another; each of the predetermined sequences has a length R; R is an integer greater than 1; and (iii) determining the p by R modulation schemes of the selected sequence; ２ mapping the bits to the R subcarriers respectively; generating a transmit signal, transmitting the generated transmission signal; A method comprising:

2. The method of claim 1 , wherein each of the predetermined sequences has a length R=2.

3. The first subgroup is １ = log ２ of A bits, A being the number of said predetermined sequence; Each modulation scheme occurring in the predetermined sequence has the same number M of symbols, and the second subgroup is ２ = log ２ 3. The method of claim 1, wherein the signal is of M bits.

4. the Hamming distance between any two of the predetermined sequences is R; and / or the number A of the predetermined sequences is less than or equal to the number Q of mutually different modulation schemes appearing in the predetermined sequences; The method according to claim 3.

5. The predetermined sequence I ｋ (1≦k≦A≦Q), is given as x ｉ (1≦i≦Q) are Q mutually distinct modulation schemes, π ｊ 5. The method of claim 4, wherein (1≦j≦R) is R permutations of {1, 2, . . . , Q}.

6. The modulation scheme appearing in the predetermined sequence is A phase shift keying or quadrature amplitude modulation scheme can be obtained by partitioning into groups having M symbols; and / or 6. A method according to claim 4 or 5, wherein the vectors are related to each other by a rotation in the complex plane.

7. The method of claim 6 , wherein the modulation schemes include binary phase shift keying (BPSK) and quadrature binary phase shift keying (QBPSK).

8. The number of said groups of p bits is where N is the N number of p bits. ｐ is the number of subcarriers used to transmit the group, and / or The generating of the transmit signal comprises the N ｐ The method of any one of claims 1 to 7, comprising the steps of: dividing, selecting, and mapping for each of said groups.

9. The N ｐ 9. The method of claim 8, wherein for each nth group of n groups, the R subcarriers are subcarriers having indices n, n+N / R, n+2N / R, . . . , n+(R-1)N / R.

10. 1. A method for radio reception, comprising: receiving a transmission; From the received transmission signal, p １ and p ２ p=p is an integer greater than 0 １ +p ２ obtaining p bits by performing a maximum likelihood estimation on the received transmitted signal; １ A first subgroup of bits and p ２ determining a second subgroup of bits; Including, (iv) the p ２ bits are respectively mapped to R subcarriers by R modulation schemes of a sequence of modulation schemes, where R is an integer greater than 1; (v) the sequence is one of a plurality of predetermined sequences of a modulation scheme, where the predetermined sequences are different from each other, each of the predetermined sequences has a length R, and the p １ bits, method.

11. The method of claim 10 , wherein each of the plurality of predetermined sequences has a length R=2.

12. The first subgroup is １ = log ２ of A bits, A being the number of said predetermined sequence; Each modulation scheme occurring in the predetermined sequence has the same number M of symbols, and the second subgroup is ２ = log ２ 12. The method according to claim 10 or 11, which is of M bits.

13. the Hamming distance between any two of the predetermined sequences is R; and / or A, the number of the predetermined sequences, is smaller than or equal to the number Q of mutually different modulation schemes appearing in the predetermined sequences; The method according to any one of claims 10 to 12.

14. obtaining a number of groups of p bits, where p is an integer greater than 1; For a group of p bits, The group of p bits is denoted by p １ A first subgroup of bits and p ２ and a second subgroup of p bits, １ and p ２ is an integer greater than 0; The p １ selecting a sequence of modulation schemes from a plurality of predetermined sequences of modulation schemes based on the bits; the predetermined sequences are different from one another; each of the predetermined sequences has a length R; R is an integer greater than 1; and, The p ２ mapping the bits to the R subcarriers respectively; generating a transmit signal, and a circuit configured to: a transmitter configured to transmit the generated transmission signal; A transmitting device comprising:

15. a receiver configured to receive a transmitted signal; From the received transmission signal, p １ and p ２ p=p is an integer greater than 0 １ +p ２ bits by performing a maximum likelihood estimation on the received transmitted signal, １ A first subgroup of bits and p ２ a circuit configured to perform the obtaining, the circuit comprising: A receiving device comprising: The p ２ bits are respectively mapped to R subcarriers by R modulation schemes from a sequence of modulation schemes, where R is an integer greater than 1; the sequence being one of a plurality of predetermined sequences of modulation formats; the predetermined sequences are different from one another; Each of the predetermined sequences has a length R, and １ bits, Receiving device.

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