Patent Description:
<CIT> relates to the technical field of signal shaping, specifically distribution matching. It presents a device for probabilistic signal shaping, and a transmitter or receiver employing said device.

<CIT> refers to methods for converting or reconverting a data signal and to a method and a system for data transmission and/or data reception.

<NPL>, concerns an implementation of an AC-DM in FPA and how to choose the input length for the CCDM to guarantee error-free decoding.

<NPL>), proposes multiset partition distribution matching (MPDM) where the composition is constant over all output sequences.

The invention is defined by the subject-matter of independent claims <NUM>, <NUM>, <NUM> and <NUM>. Preferred embodiments are defined by the subject-matter of dependent claims <NUM>-<NUM>, <NUM>, <NUM>-<NUM> and <NUM>.

Accordingly, in one or more example aspects, the functions described may be implemented in hardware, software, or any combination thereof.

Communication over a channel is possible if the transmission rate over the channel satisfies a capacity based on the transmission power and the signal-to-noise ratio (SNR). The Shannon Capacity models the amount of information that can be transmitted across a noise communication channel in which certain signal values can be confused with each other. The Shannon Capacity in an additive white Gaussian noise (AWGN) channel is achievable with a Gaussian distribution of the information. For example, uniform signaling (e.g., a non-Gaussian distribution of information) may optimistically achieve an achievable information rate (AIR) that is <NUM> dB (<NUM> bits per dimension (bit/<NUM>-D)) away from the capacity of the AWGN channel (sometimes referred to as the "shaping gap").

Techniques for reducing (or closing) the shaping gap include generating a non-uniform distribution of the information. For example, in geometric shaping, instead of using a uniform distribution, an equiprobable signal may be constructed with constellation points arranged with a Gaussian-like geometry. Geometric shaping enables large shaping gains for symbol-wise forward error correction (FEC). However, geometric shaping may provide limited Gray mapping and/or may be difficult to achieve shaping gains in bit-interleaved coded modulation (BICM) with binary FEC.

Another technique for reducing the shaping gap includes probabilistic shaping. In probabilistic shaping, instead of using a uniform distribution, aspects induce a Gaussian-like signal distribution with a uniform constellation. Examples of probabilistic shaping including Trellis shaping and shell mapping. Probabilistic amplitude shaping is another technique for employing probabilistic shaping that has achieved high throughput for commercial use in optical core networks (e.g., over <NUM> GB/second). Probabilistic shaping offers low-complexity and flexible integration with existing BICM schemes.

Aspects disclosed herein provide techniques for improving the spectral efficiency and achievable information rate for communication over a channel, such as an AWGN channel. For example, disclosed techniques utilize a distribution matcher that includes a decompresser to convert a sequence of information bits into a set of symbols. The sequence of information bits may be uniformly distributed, such as in <NUM> NR. However, aspects presented herein are not limited to application with <NUM> NR. The decompresser may generate the sequence of symbols based on a target probability mass function (PMF), such as a Maxwell-Boltzmann Distribution, and a symbol block length. The sequence of symbols may be transmitted to a receiver for processing to determine the transmitted information.

The distribution matcher may also include a compressor to convert the set of symbols into a sequence of compressed information bits. In a fixed-to-fixed scheme, the distribution matcher may include a comparator to compare the sequence of information bits to the sequence of compressed information bits to determine how many bits were not converted into the set of symbols. In some examples, the distribution matcher may provide the output of the comparator to the receiver so that the receiver can determine how to process the set of symbols. For example, based on a compressor at the receiver, the receiver may compress the set of symbols to generate information bits based on the target PMF, which may result in extra bits. The receiver may use the output of the comparator (e.g., discard signaling) to determine how many bits to discard.

In another aspect, the distribution matcher may employ a variable-to-fixed scheme in which the decompressor is configured with a "back-off" limit. The back-off limit may limit the amount of information bits that the decompressor may convert to the set of symbols so that extra bits are not transmitted to the receiver for discarding. Moreover, the variable-to-fixed scheme may limit the amount of overhead (e.g., compared to the fixed-to-fixed scheme) as a comparator is not needed and, thus, the distribution matcher may forego transmitting discard signaling.

<FIG> is a diagram illustrating an example of a wireless communications system and an access network <NUM> including base stations <NUM> or <NUM> and UEs <NUM>.

As an example, a wireless transmitter, such as a base station <NUM> / <NUM> and/or a UE <NUM>, may include a transmission distribution matching component <NUM>. In certain aspects, the transmission distribution matching component <NUM> may be configured to decompress a first sequence of information bits for wireless transmission to output a sequence of shaped symbols. The example transmission distribution matching component <NUM> may also be configured to compress the sequence of shaped symbols to output a second sequence of compressed information bits. Additionally, the example transmission distribution matching component <NUM> may be configured to transmit, to a receiver, a signal comprising the sequence of shaped symbols.

Still referring to <FIG>, in certain aspects, a wireless receiver, such as a base station <NUM> / <NUM> and/or a UE <NUM>, may include a receiver distribution matching component <NUM>. In certain aspects, the receiver distribution matching component <NUM> may be configured to receive, from a transmitter, a signal comprising a sequence of shaped symbols. The example receiver distribution matching component <NUM> may also be configured to compress the sequence of shaped symbols to output a sequence of compressed information bits, and where the compression is based on the sequence of shaped symbols and a target probability mass function (PMF).

Although the following description may be focused on <NUM> NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other communication technologies, such as optical communication, in which signaling may occur over a noisy channel.

The wireless communications system (also referred to as a wireless wide area network (WWAN)) includes the base stations <NUM>, the UEs <NUM>, an Evolved Packet Core (EPC) <NUM>, and another core network <NUM> (e.g., a <NUM> Core (5GC)).

The transmit (TX) processor (e.g., a TX processor <NUM>) and the receive (RX) processor (e.g., an RX processor <NUM>) implement layer <NUM> functionality associated with various signal processing functions. Each spatial stream may then be provided to a different antenna <NUM> via a separate transmitter <NUM> TX. Each transmitter <NUM> TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE <NUM>, each receiver <NUM> RX receives a signal through its respective antenna <NUM>. Each receiver <NUM> RX recovers information modulated onto an RF carrier and provides the information to an RX processor <NUM>. A TX processor <NUM> and the RX processor <NUM> implement layer <NUM> functionality associated with various signal processing functions. These soft decisions may be based on channel estimates computed by a channel estimator <NUM>. The data and control signals are then provided to a controller/processor <NUM>, which implements layer <NUM> and layer <NUM> functionality.

Channel estimates derived by the channel estimator <NUM> from a reference signal or feedback transmitted by the base station <NUM> may be used by the TX processor <NUM> to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor <NUM> may be provided to different antenna <NUM> via separate transmitters <NUM> TX. Each transmitter <NUM> TX may modulate an RF carrier with a respective spatial stream for transmission.

Each receiver <NUM> RX receives a signal through its respective antenna <NUM>. Each receiver <NUM> RX recovers information modulated onto an RF carrier and provides the information to the RX processor <NUM>.

Aspects of the transmission distribution matching component <NUM> may be performed by the UE <NUM> (e.g., by at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>) and/or the base station <NUM> (e.g., by at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>).

Aspects of the receiver distribution matching component <NUM> may be performed by the UE <NUM> (e.g., by at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>) and/or the base station <NUM> (e.g., by at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>).

Techniques for reducing (or closing) the shaping gap include generating a non-uniform distribution of the information. For example, in geometric shaping, instead of using a uniform distribution, an equiprobable signal is constructed with constellation points arranged with a Gaussian-like geometry. Geometric shaping enables large shaping gains for symbol-wise forward error correction (FEC). However, geometric shaping may provide limited Gray mapping and/or may be difficult to achieve shaping gains in bit-interleaved coded modulation (BICM) with binary FEC.

Probabilistic amplitude shaping (PAS) utilizes reverse concatenation whereby the shaping precedes FEC coding. <FIG> illustrates a communication system <NUM> employing PAS, as presented herein. The communication system <NUM> includes a wireless transmitter <NUM> and a wireless receiver <NUM>. For example, an information source <NUM> may generate k information bits that is received by a transmitter distribution matcher <NUM>. The transmitter distribution matcher <NUM> may generate a sequence of symbols (n). The sequence of symbols (n) may be received by an amplitude to bit component <NUM> and an FEC encoder <NUM> to produce a set of bits where some are shaped and others are uniformly distributed. After the encoding, the bits are mapped, e.g., to quadrature amplitude modulation (QAM) symbols by a QAM mapping component <NUM>. A signal <NUM> (e.g., the symbols) is then transmitted over the wireless medium to the wireless receiver <NUM>, e.g., over a channel <NUM>.

At the wireless receiver <NUM>, the signal <NUM> is received by a bitwise log-likelihood ratios (LLR) demapper component <NUM> to demap the symbols of the signal <NUM>. The demapped symbols are received by the FEC decoder <NUM> and a bit to amplitude component <NUM> to decode the bits. The decoded bits are provided to a receiver distribution dematcher <NUM> to uniformly distribute the received bits, which may then be sent to their destination.

Aspects disclosed herein provide techniques for improving the spectral efficiency and achievable information rate for communication over an AWGN channel. For example, disclosed techniques utilize a distribution matcher that includes a decompresser to convert a sequence of information bits (u) into a set of symbols. The sequence of information bits (u) may be uniformly distributed. As one non-limiting example, in <NUM> NR, the sequence of information bits may be uniformly distributed. The decompresser may generate the sequence of symbols based on a target probability mass function (PMF), such as a Maxwell-Boltzmann Distribution, and a symbol block length (n). The sequence of symbols may be transmitted to a receiver for processing to determine the transmitted information.

The distribution matcher may also include a compressor to convert the set of symbols into a sequence of compressed information bits (û). In a fixed-to-fixed scheme, the distribution matcher may include a comparator to compare the sequence of information bits (u) to the sequence of compressed information bits (û) to determine how many information bits were not converted into the set of symbols. In some examples, the distribution matcher may provide the output of the comparator to the receiver so that the receiver can determine how to process the set of symbols. For example, based on a compressor at the receiver, the receiver may compress the set of symbols to generate information bits based on the target PMF, which may result in extra bits. The receiver may use the output of the comparator (e.g., discard signaling) to determine how many bits to discard.

In another aspect, the distribution matcher may employ a variable-to-fixed scheme in which the decompressor is configured with a "back-off" limit. The back-off limit may limit the amount of information bits that the decompressor may convert to the set of symbols so that extra bits are not transmitted to the receiver for discarding. Moreover, the variable-to-fixed scheme may limit the amount of overhead (e.g., compared to the fixed-to-fixed scheme) as a comparator is not needed and, thus, the distribution matcher may forego transmitting discard signaling with information about the number of bits to discard at the receiver. In such examples, when employing the variable-to-fixed scheme, the rate loss compared to target entropy may be improved compared to when employing the fixed-to-fixed scheme.

<FIG> illustrates a block diagram of an example fixed-to-fixed transmitter distribution matcher <NUM> and a fixed-to-fixed receiver distribution dematcher <NUM>, as presented herein. The example fixed-to-fixed transmitter distribution matcher <NUM> employs reversed back-to-back compression and decompression. For example, the example fixed-to-fixed transmitter distribution matcher <NUM> includes a decompression component <NUM>, a compression component <NUM>, and a comparator component <NUM>. The decompression component <NUM> receives a sequence (u) of k information bits (e.g. from the information source <NUM> of <FIG>) and generates a set of symbols (n). For example, the decompression component <NUM> may generate the set of symbols (n) based on a target PMF (e.g., such as the Maxwell-Boltzmann Distribution) and a symbol block length (n). The set of symbols (n) may represent shaped real positive amplitude symbols. The set of symbols (n) may then be transmitted to a receiver, for example, over a channel.

As shown in <FIG>, the set of symbols (n) are also provided to the compression component <NUM>, which applies the target PMF to generate a sequence (û) of k' compressed information bits. The comparator component <NUM> receives the sequence (u) of k information bits and the sequence (û) of k' compressed information bits to generate a discard signal <NUM>. The discard signal <NUM> provides information about postfix bits (e.g., the last bits or last segment of bits in the sequence) and may be based on a difference in the quantity of bits of the sequence (û) and the sequence (u). For example, the decompression component <NUM> may receive a sequence (u) of <NUM> information bits. Based on the symbol block length and the target PMF, the decompression component <NUM> may generate the set of symbols (n) using <NUM> bits. The compression component <NUM> may receive the set of symbols (n) and generate the sequence (û) of <NUM> compressed information bits. The comparator component <NUM> may then compare the sequence (u) of <NUM> information bits and the sequence (û) of <NUM> compressed information bits and determine that <NUM> bits were not used. Thus, the discard signal <NUM> may indicate that <NUM> bits were not used.

Thus, the fixed-to-fixed transmitter distribution matcher <NUM> may attempt to determine whether an n-length sequence of symbols distributed according to the target PMF can be compressed to the given information bit sequence (u) of at least length k. If the answer is yes, then it may be appreciated that the quantity of the first k information bits of the sequence (u) is less than or equal to quantity of the first k' compressed information bits of the sequence (û) and are identical. Moreover, the first k' compressed information bits of the sequence (û) may be part of a prefix code. As a result, the discard signal <NUM> may indicate to discard zero bits. As used herein, a prefix code may comprise a type of code system for which a "prefix property" holds. In some such systems, two code words may not share a prefix (e.g., an initial segment of bits). Additionally, or alternatively, in some such systems, a whole code word in the system may not comprise a prefix (e.g., an initial segment of bits) of another code word in the system.

However, if the answer is no (e.g., an n-length sequence of symbols distributed according to the target PMF cannot be compressed to the given information bit sequence (u) of at least length k), then it may be appreciated that the discard signal <NUM> may indicate to discard one or more bits. For example, only a portion of the first k information bits of the sequence (u) and the k' compressed information bits of the sequence (û) may be the same. For example, the quantity of the portion of bits that are the same may be determined by Equation <NUM> (below).

In Equation <NUM>, the variable "k" represents the quantity of information bits of the sequence (u), the variable "k'" represents the quantity of compressed information bits of the sequence (û), and the variable "discard" represents the difference in the respective quantities. Thus, based on Equation <NUM>, the identical bits may be determined based on the minimum of the quantity of information bits of the sequence (u) and the quantity of compressed information bits of the sequence (û) less the difference in the respective quantities. Moreover, it may be appreciated that the sequence (u) and the sequence (û) are not the same starting at the bit (min(k, k') - discard + <NUM>).

In the illustrated example of <FIG>, the fixed-to-fixed receiver distribution dematcher <NUM> includes a compression component <NUM> and a discarding component <NUM>. The example compression component <NUM> receives the set of symbols (n) and generates the sequence (û) of k' compressed information bits based on the target PMF. Aspects of the compression component <NUM> may be similar to the compression component <NUM> of the fixed-to-fixed transmitter distribution matcher <NUM>. That is, the sequence (û) of k' compressed information bits generated by the compression components <NUM>, <NUM> may be the same. The example discarding component <NUM> receives the sequence (û) of k' compressed information bits from the compression component <NUM> and the discard signal <NUM> from the fixed-to-fixed transmitter distribution matcher <NUM> and determines which, if any, bits to discard.

As shown in <FIG>, transmitting the set of symbols (n) may include overhead. For example, if an n-length sequence of symbols distributed according to the target PMF cannot be compressed to the given information bit sequence (u) of at least length k, then the set of symbols (n) may include additional bits that the receiver discards. Additionally, the transmitter transmits the discard signal <NUM>. In some examples, the discard signal <NUM> may be of length "dec2bin(discard)", which converts the decimal value of the sequence of bits to discard into a binary value. Thus, the total value of bits that may be conveyed by the transmitter to the receiver may be determined by Equation <NUM> (below).

In Equation <NUM>, the variable "k̂" represents the total value of bits conveyed by the transmitter, the variable "k" represents the quantity of information bits of the sequence (u), the variable "k'" represents the quantity of compressed information bits of the sequence (û), the variable "discard" represents the difference in the respective quantities, and the variable "length(dec2bin(discard))" represents the decimal-to-binary value of the discarded bits.

<FIG> illustrates a block diagram of an example implementation of a fixed-to-fixed transmitter distribution matcher <NUM> and an example implementation of a fixed-to-fixed receiver distribution dematcher <NUM>, as presented herein. The example fixed-to-fixed transmitter distribution matcher <NUM> employs reversed back-to-back compression and decompression. As shown in <FIG>, the decompression component <NUM> of <FIG> may be implemented by an arithmetic decoding component <NUM>, the compression component <NUM> of <FIG> may be implemented by an arithmetic coding component <NUM>, and the compression component <NUM> of <FIG> may be implemented by an arithmetic coding component <NUM>. Aspects of the comparator component <NUM> may be implemented by the comparator component <NUM> of <FIG>. Aspects of the discard signal <NUM> may be implemented by the discard signal <NUM> of <FIG>. Aspects of the discarding component <NUM> may be implemented by the discarding component <NUM> of <FIG>.

The example arithmetic decoding component <NUM> and the arithmetic coding components <NUM>, <NUM> may perform entropy decoding/encoding. Applying entropy decoding/encoding may improve compression ratios, which may allow more bits to be converted into symbols and, thus, allow an n-length sequence of symbols distributed according to the target PMF to be compressed to the given information bit sequence (u) of at least length k.

However, it may be appreciated that other examples may employ other techniques for coding. For example, the fixed-to-fixed transmitter distribution matcher and the fixed-to-fixed receiver distribution matcher may employ Huffman coding, range coding, or universal coding.

As described above, the fixed-to-fixed distribution matcher may transmit additional bits (e.g., overhead) that are discarded by the receiver. Thus, it may be beneficial to enable the decompression component to "back off" or terminate early the decompression procedure on a sequence (u) of k information bits. That is, if the decompression component receives the sequence (u) of <NUM> information bits, but the decompression component generates the set of symbols (n) based on the first <NUM> information bits, then the decompression component may stop processing the remaining <NUM> information bits. Thus, the quantity of discarded bits is reduced to zero as the set of symbols (n) includes those bits that were used. Moreover, a discard signal is not generated as the signal received by the receiver does not include bits to discard.

For example, and with respect to arithmetic coding, for the arithmetic coding to be a prefix code and to be recoverable (e.g., uniquely decodable) from a length-n symbol sequence (s), Equation <NUM> (below) may apply.

In Equation <NUM>, the variable "k" represents the quantity of bits, the variable "s" represents the sequence of length-n symbols, and the variable "P(S)" represents a probability of the sequence S of length-n symbols. For example, arithmetic coding takes n symbols and compresses them to k bits for which Equation <NUM> applies. However, when decompressing a random bit sequence, Equation <NUM> may not apply. Equation <NUM> (below) provides a techniques for averaging that may be beneficial when applying arithmetic coding.

In Equation <NUM>, the variable "H(s)" represents the entropy of the sequence of length-n symbols, the variable "E[k]" represents the expectation applied to the k bits (e.g., an average with respect to the probability P(S)), and the variable "P(S)" represents the probability of the sequence S of length-n symbols. Based on Equation <NUM>, it may be appreciated that it may be possible to bound the average rate, in bits per symbol, of the arithmetic coding, as shown in Equation <NUM> (below).

In Equation <NUM>, the variable "H(s)" represents the entropy of the sequence of length-n symbols, the variable "E[k]" represents the expectation applied to the k bits (e.g., an average with respect to the probability P(S)), and the variable "n" represents the length of the symbols. On average, and as n increases, the maximum possible bits per symbol compression is H(s) + <NUM>. Thus, given an input of a random bit sequence of length k, if the decompression component (e.g., the arithmetic decoding component <NUM> of <FIG>) stops decoding after n̂ symbols, then the conveyed quantity of bits (k̂) may be greater than the k bits of Equation <NUM>. The value of n̂ symbols may be determined by applying Equation <NUM> (below). The conveyed quantity of bits (k̂) may be determined by applying Equation <NUM> (below).

In Equation <NUM>, the variable "n̂" represents the quantity of symbols at which to stop the decompression procedure, the variable "k" represents the quantity of information bits, and the variable "H(s)" represents the entropy of the sequence of length-n symbols.

In Equation <NUM>, the variable "k̂" represents the quantity of conveyed bits, and the variable "P(ŝ)" represents the probability of the sequence (ŝ) of length-n̂ symbols.

Thus, by "backing off" or stopping the decompression procedure after n̂ symbols (and so the sequence ŝ of length-n̂ symbols is less than or equal to the sequence s of length-n symbols), then a codeword of length k̂ may be uniquely decodable from the n̂ ≤ n symbols.

<FIG> illustrates a block diagram of an example variable-to-fixed transmitter distribution matcher <NUM> and an example variable-to-fixed receiver distribution dematcher <NUM>, as presented herein. Similar to the example fixed-to-fixed transmitter distribution matcher <NUM> of <FIG>, the example variable-to-fixed transmitter distribution matcher <NUM> employs reversed back-to-back compression and decompression. In the illustrated example, aspects of the variable-to-fixed transmitter distribution matcher <NUM> and the variable-to-fixed receiver distribution dematcher <NUM> may be implemented using arithmetic coding techniques, such as an arithmetic coding component and an arithmetic decoding component.

As shown in <FIG>, the variable-to-fixed transmitter distribution matcher <NUM> includes a decompression component <NUM> and a compression component <NUM>. The decompression component <NUM> receives a sequence (u) of k information bits (e.g. from the information source <NUM> of <FIG>) and generates a set of symbols (n̂). For example, the decompression component <NUM> may generate the set of symbols (n̂) based on a target PMF (p) (e.g., such as the Maxwell-Boltzmann Distribution) and a nominal symbol block length (n'). The set of symbols (n̂) may represent fixed n̂ shaped real positive amplitude symbols. The set of symbols (n̂) may then be transmitted to a receiver, for example, over a channel.

In the illustrated example of <FIG>, the decompression component <NUM> stops the decompression procedure after the set of symbols (n̂) are generated. To determine the quantity of symbols (n̂) to generate, the decompression component <NUM> applies Equation <NUM> (below).

In Equation <NUM>, the variable "n̂" represents the quantity of symbols at which to stop the decompression procedure, the variable "k" represents the quantity of information bits, and the variable "L" corresponds to an entropy under a target PMF (p). The value of L may be determined by applying Equation <NUM> (below).

In Equation <NUM>, the variable "Hp" represents the entropy of the target PMF (p). Thus, as shown in Equation <NUM>, the value of L may be calculated as the sum of an integer and the entropy Hp. In the example of Equation <NUM>, the integer is two. However, in some examples, the value of L may be determined by applying Equation <NUM> (below).

In Equation <NUM>, the variable "Hp" represents the entropy of the target PMF (p). Thus, as shown in Equation <NUM>, the value of L may be calculated as the sum of an integer and the ceiling function of the entropy Hp. In the example of Equation <NUM>, the integer is one.

By applying Equation <NUM>, the quantity of symbols of the set of symbols (n̂) is less than the quantity of symbols of the set of symbols (n) of <FIG>. Additionally, the quantity of conveyed bits k̂ is less than the k information bits. Thus, additional (e.g., bits to discard at the receiver) are not transmitted.

As an example, the decompression component <NUM> may receive a sequence (u) of <NUM> information bits and the value of L may be <NUM>. By applying Equation <NUM>, the decompression component <NUM> may stop the decompression procedure at <NUM> symbols (e.g., <NUM> bits / <NUM> = <NUM> symbols). The transmitter may then transmit the <NUM> symbols.

As described above, the decompression component <NUM> may stop the decompression procedure after generating the set of symbols (n̂). That is, instead of processing the full sequence (u) of k information bits, the decompression component <NUM> may stop after k̂ bits, and where k̂ is less than the k information bits. For example, in the above example, the decompression component <NUM> may use <NUM> bits of the <NUM> information bits to generate the <NUM> symbols.

As shown in <FIG>, the set of symbols (n̂) are also provided to the compression component <NUM>. The compression component <NUM> may receive the set of symbols (n̂) and generate the sequence (û) of k̂ conveyed bits. Thus, the compression component <NUM> may enable the variable-to-fixed transmitter distribution matcher <NUM> to determine which bits of the sequence (u) of k information bits were converted to symbols. For example, in the above example, the compression component <NUM> may determine that the <NUM> symbols conveyed to the receiver correspond to bits <NUM> to <NUM> of the sequence (u) of <NUM> information bits. In such examples, the decompression component <NUM> may the information regarding the sequence (û) of k̂ conveyed bits to determine which bit to start the next decompression procedure. For example, the decompression component <NUM> may start the next decompression procedure on bits <NUM> to <NUM> of the sequence (u) of <NUM> information bits. Moreover, it may be appreciated that the set of symbols (n̂) generated by the next decompression procedure may be different than the previous set of symbols (n̂). For example, in the above example, the quantity of information bits to process for the next decompression procedure is <NUM> information bits and with the same value of L (e.g., four), the next decompression procedure may generate five symbols based on Equation <NUM> (e.g., <NUM> bits / <NUM> = <NUM> symbols).

In the illustrated example of <FIG>, the variable-to-fixed receiver distribution dematcher <NUM> includes a compression component <NUM>. The example compression component <NUM> receives the set of symbols (n̂) and generates the sequence (û) of k̂ conveyed bits based on the target PMF (p). Aspects of the compression component <NUM> may be similar to the compression component <NUM> of the variable-to-fixed transmitter distribution matcher <NUM>. That is, the sequence (û) of k̂ conveyed bits generated by the compression components <NUM>, <NUM> may be the same.

As shown in <FIG>, the set of symbols (n̂) may comprise a varying quantity of symbols. Moreover, the sequence (û) of k̂ conveyed bits may also be a varying quantity. To improve the compression procedure performed at the compression components <NUM>, <NUM>, the respective compression components <NUM>, <NUM> reset arithmetic coding parameters after performing the compression procedure on n̂ symbols. For example, for the first compression procedure in the above example, the compression components <NUM>, <NUM> may reset the arithmetic coding parameters after processing the <NUM> symbols, and for the second compression procedure, the compression components <NUM>, <NUM> may reset the arithmetic coding parameters after processing the five symbols.

As described above, aspects of the decompression component <NUM> and the compression components <NUM>, <NUM> may be implemented by arithmetic coding. Additionally, compared to the fixed-to-fixed distribution matching scheme of <FIG>, the variable-to-fixed distribution matching scheme of <FIG> may reduce overhead by, for example, avoiding the transmitting of bits that are discarded and by skipping the transmitting of a discard signal. As a result, the variable-to-fixed distribution matching scheme of <FIG> may improve spectral efficiency, reduce rate loss due to shaping, and may improve the achievable information rate (e.g., improvement in gain) compared to the fixed-to-fixed distribution matching scheme.

<FIG> illustrates a block diagram of an example implementation of a variable-to-fixed transmitter distribution matcher <NUM> and an example implementation of a variable-to-fixed receiver distribution dematcher <NUM>, as presented herein. The variable-to-fixed transmitter distribution matcher <NUM> employs reversed back-to-back compression and decompression. As shown in <FIG>, the decompression component <NUM> of <FIG> may be implemented by an arithmetic decoding component <NUM>, the compression component <NUM> of <FIG> may be implemented by an arithmetic coding component <NUM>, and the compression component <NUM> of <FIG> may be implemented by an arithmetic coding component <NUM>.

The example arithmetic decoding component <NUM> and the arithmetic coding components <NUM>, <NUM> may perform entropy decoding/encoding. Applying entropy decoding/encoding may improve compression ratios, which may allow more bits to be converted into symbols and, thus, allow an n'-length sequence of symbols distributed according to the target PMF to be compressed to the given information bit sequence (û) of k̂ conveyed bits.

However, it may be appreciated that other examples may employ other techniques for coding. For example, the variable-to-fixed transmitter distribution matcher and the variable-to-fixed receiver distribution matcher may employ Huffman coding, range coding, or universal coding.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by a wireless transmitter, such as a UE (e.g., the UE <NUM>, the UE <NUM>, and/or an apparatus <NUM> of <FIG>) or a base station (e.g., the base station <NUM>/<NUM>, the base station <NUM>). Optional aspects are illustrated with a dashed line. The method may facilitate improving spectral efficiency by reducing rate loss due to shaping and improving the achievable information rate (e.g., improvement in gain) for communications in a noisy channel.

At <NUM>, the wireless transmitter decompresses a first sequence of information bits for wireless transmission to output a sequence of, or a set of, shaped symbols, as described in connection with the set of symbols (n) of <FIG> and/or <NUM>, and/or the set of symbols (n̂) of <FIG> and/or <NUM>. For example, <NUM> may be performed by a decompression component <NUM> of the apparatus <NUM> of <FIG>.

According to the claimed invention, the decompression is based on a target symbol length and a target probability mass function (PMF).

In some examples, the decompression is based on arithmetic decoding, as described in connection with <FIG> and/or <NUM>. In some examples, the decompression is based on probabilistic decompression. In some examples, the decompression is based on one or more of Huffman coding, range coding, or universal coding. In some examples, the decompression of the first sequence of information bits is performed at a distribution matcher, such as the example fixed-to-fixed transmitter distribution matcher <NUM> of <FIG>, the example fixed-to-fixed transmitter distribution matcher <NUM> of <FIG>, the example variable-to-fixed transmitter distribution matcher <NUM> of <FIG>, and/or the example variable-to-fixed transmitter distribution matcher <NUM> of <FIG>.

At <NUM>, the wireless transmitter compresses the sequence of shaped symbols to output a second sequence of compressed information bits, as described in connection with the sequence (û) of k' compressed information bits of <FIG> and/or <NUM>, and/or the sequence (û) of k̂ conveyed bits of <FIG> and/or <NUM>. For example, <NUM> may be performed by a compression component <NUM> of the apparatus <NUM> of <FIG>.

According to the claimed invention, the compression is based on the target PMF.

In some examples, the compression is based on arithmetic coding, as described in connection with <FIG> and/or <NUM>. In some examples, the compression is based on probabilistic compression.

At <NUM>, the wireless transmitter transmits, to a receiver, a signal comprising the sequence of shaped symbols, as described in connection with the signal <NUM> of <FIG>, the set of symbols (n) of <FIG> and/or <NUM>, and/or the set of symbols (n̂) of <FIG> and/or <NUM>. For example, <NUM> may be performed by a signal transmission component <NUM> of the apparatus <NUM> of <FIG>.

At <NUM>, the wireless transmitter may signal, to the receiver, information about bits to discard at the receiver based on a comparison of the first sequence of information bits and the second sequence of compressed information bits, as described in connection with the discard signal <NUM> of <FIG>. For example, <NUM> may be performed by a discard component <NUM> of the apparatus <NUM> of <FIG>.

In some examples, the first sequence of information bits may comprise a variable number of information bits, as described in connection with the first decompression procedure and the second decompression procedure of <FIG>. In such examples, the first sequence of information bits may be a prefix subset (sometimes referred to as a "prefix code") of a fixed sequence of information bits. For example, the first sequence of information bits may correspond to the <NUM> information bits and the fixed sequence of information bits may correspond to the <NUM> information bits. For example, at <NUM>, the wireless transmitter may stop decompressing the fixed sequence of information bits, as described in connection with the decompression component <NUM> of <FIG> and the nominal symbol block length (n'). For example, <NUM> may be performed by a stopping component <NUM> of the apparatus <NUM> of <FIG>. For example, the wireless transmitter may apply Equation <NUM> (above) to stop decompressing the fixed sequence of information bits after generating the set of symbols (n̂).

At <NUM>, the wireless transmitter may restart decompressing remaining information bits based on a variable determined from the second sequence of compressed information bits, as described in connection with the second decompression procedure of <FIG>. For example, <NUM> may be performed by the decompression component <NUM> of the apparatus <NUM> of <FIG>. For example, the wireless transmitter may restart decompressing the remaining information bits <NUM> to <NUM> of the sequence (u) of <NUM> information bits of <FIG>.

In some examples, the sequence of shaped symbols transmitted to the received is based on a fixed sequence of information bits scaled by an integer number, as described in connection with Equations <NUM> and <NUM>. In some examples, the integer number is based on a target entropy (H(s)) for the target PMF (p).

In some examples, at <NUM>, the wireless transmitter may perform FEC encoding to the sequence of shaped symbols output based on the decompression of the first sequence of information bits, as described in connection with the FEC encoder <NUM> of <FIG>. For example, <NUM> may be performed by an FEC encoding component <NUM> of the apparatus <NUM> of <FIG>.

The apparatus <NUM> is a wireless transmitter. and includes a cellular baseband processor <NUM> (also referred to as a modem) coupled to a cellular RF transceiver <NUM>. In some aspects, the apparatus <NUM> may be a UE <NUM> or a base station <NUM> or <NUM>. In some aspects, the apparatus may include additional components for wireless communication, including any combination of one or more subscriber identity modules (SIM) cards <NUM>, an application processor <NUM> coupled to a secure digital (SD) card <NUM> and a screen <NUM>, a Bluetooth module <NUM>, a wireless local area network (WLAN) module <NUM>, a Global Positioning System (GPS) module <NUM>, and/or a power supply <NUM>. The cellular baseband processor <NUM> communicates through the cellular RF transceiver <NUM> with the UE <NUM> and/or base station <NUM>/<NUM>. In one configuration, the apparatus <NUM> may be a modem chip and include just the cellular baseband processor <NUM>, and in another configuration, the apparatus <NUM> may be the entire UE (e.g., see the UE <NUM> of <FIG>) and include the additional modules of the apparatus <NUM>. The cellular baseband processor <NUM> may be a component of the base station <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>. In one configuration, the apparatus <NUM> may be a modem chip and include just the cellular baseband processor <NUM>, and in another configuration, the apparatus <NUM> may be the entire base station (e.g., see the base station <NUM> of <FIG>) and include the additional modules of the apparatus <NUM>.

The communication manager <NUM> includes a decompression component <NUM> that is configured to decompress a first sequence of information bits for wireless transmission to output a sequence of shaped symbols, for example, as described in connection with <NUM> of <FIG>. The example decompression component <NUM> may also be configured to restart decompressing remaining information bits based on a variable determined from the second sequence of compressed information bits, for example, as described in connection <NUM> of <FIG>.

The communication manager <NUM> also includes a compression component <NUM> that is configured to compress the sequence of shaped symbols to output a second sequence of compressed information bits, for example, as described in connection with <NUM> of <FIG>.

The communication manager <NUM> also includes a signal transmission component <NUM> that is configured to transmit, to a receiver, a signal comprising the sequence of shaped symbols, for example, as described in connection with <NUM> of <FIG>.

The communication manager <NUM> also includes a discard component <NUM> that is configured to signal, to the receiver, information about bits to discard at the receiver based on a comparison of the first sequence of information bits and the second sequence of compressed information bits, for example, as described in connection with <NUM> of <FIG>.

The communication manager <NUM> also includes a stopping component <NUM> that is configured to stop decompressing the fixed sequence of information bits, for example, as described in connection with <NUM> of <FIG>.

The communication manager <NUM> also includes an FEC encoding component <NUM> that is configured to perform FEC encoding to the sequence of shaped symbols output based on the decompression of the first sequence of information bits, for example, as described in connection with <NUM> of <FIG>.

In one configuration, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, includes means for decompressing a first sequence of information bits for wireless transmission to output a sequence of shaped symbols. The example apparatus <NUM> also includes means for compressing the sequence of shaped symbols to output a second sequence of compressed information bits. The example apparatus <NUM> also includes means for transmitting, to a receiver, a signal comprising the sequence of shaped symbols.

In another configuration, the example apparatus <NUM> also includes means for signaling, to the receiver, information about postfix bits to discard at the receiver based on a comparison of the first sequence of information bits and the second sequence of compressed information bits.

In another configuration, the example apparatus <NUM> also includes means for stopping decompressing the fixed sequence of information bits. The example apparatus <NUM> also includes means for restarting decompressing remaining information bits based on a variable determined from the second sequence of compressed information bits.

In another configuration, the example apparatus <NUM> also includes means for performing FEC encoding to the sequence of shaped symbols output based on the decompressing of the first sequence of information bits.

The aforementioned means may be one or more of the aforementioned components of the apparatus <NUM> configured to perform the functions recited by the aforementioned means. As described supra, the apparatus <NUM> may include the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>. As such, in one configuration, the aforementioned means may be the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM> configured to perform the functions recited by the aforementioned means.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by a wireless receiver, such as a UE (e.g., the UE <NUM>, the UE <NUM>, and/or an apparatus <NUM> of <FIG>) or a base station (e.g., the base station <NUM>/<NUM>, the base station <NUM>). Optional aspects are illustrated with a dashed line. The method may facilitate improving spectral efficiency by reducing rate loss due to shaping and improving the achievable information rate (e.g., improvement in gain) for communications in a noisy channel.

At <NUM>, the wireless receiver receives, from a transmitter, a signal comprising a sequence of shaped symbols, as described in connection with the signal <NUM> of <FIG>, the set of symbols (n) of <FIG> and/or <NUM>, and/or the set of symbols (n̂) of <FIG> and/or <NUM>. For example, <NUM> may be performed by a signal reception component <NUM> of the apparatus <NUM> of <FIG>.

At <NUM>, the wireless receiver receives, from the transmitter, information about bits to discard, as described in connection with the discard signal <NUM> of <FIG>. For example, <NUM> may be performed by a discard component <NUM> of the apparatus <NUM> of <FIG>.

At <NUM>, the wireless receiver compresses the sequence of shaped symbols to output a sequence of compressed information bits, and where the compressing is based on the sequence of shaped symbols and a target probability mass function (PMF), as described in connection with the sequence (û) of k' compressed information bits of <FIG> and/or <NUM>, and/or the receiver bits of <FIG> and/or <NUM>. For example, <NUM> may be performed by a compression component <NUM> of the apparatus <NUM> of <FIG>.

In some examples, the sequence of shaped symbols comprises a variable number of information bits, as described in connection with the first decompression procedure and the second decompression procedure of <FIG>. In such examples, the first sequence of information bits may be a prefix subset of a fixed sequence of information bits. For example, the first sequence of information bits may correspond to the <NUM> information bits and the fixed sequence of information bits may correspond to the <NUM> information bits. In some examples, the sequence of shaped symbols received at the wireless receiver is based on the fixed sequence of information bits scaled by an integer number, as described in connection with Equations <NUM> and <NUM>. In some examples, the integer number is based on a target entropy (H(s)) for the target PMF (p).

In some examples, the compressing is based on arithmetic coding, as described in connection with <FIG> and/or <NUM>. In some examples, the compressing is based on one or more of Huffman coding, range coding, or universal coding. In some examples, the compressing is based on probabilistic compression. In some examples, the compressing of the sequence of shaped symbols is performed at a distribution dematcher, such as the example fixed-to-fixed receiver distribution dematcher <NUM> of <FIG>, the example fixed-to-fixed receiver distribution dematcher <NUM> of <FIG>, the example variable-to-fixed receiver distribution dematcher <NUM> of <FIG>, and/or the example variable-to-fixed receiver distribution dematcher <NUM> of <FIG>.

In some examples, the sequence of shaped symbols comprises shaped positive amplitude symbols.

In some examples, at <NUM>, the wireless receiver may perform FEC decoding of the sequence of shaped symbols output prior to the compressing, as described in connection with the FEC decoder <NUM> of <FIG>. For example, <NUM> may be performed by an FEC decoding component <NUM> of the apparatus <NUM> of <FIG>.

The apparatus <NUM> is a wireless receiver and includes a cellular baseband processor <NUM> (also referred to as a modem) coupled to a cellular RF transceiver <NUM>. In some aspects, the apparatus <NUM> may be a UE <NUM> or a base station <NUM> or <NUM>. In some aspects, the apparatus may include additional components for wireless communication, including any combination of one or more subscriber identity modules (SIM) cards <NUM>, an application processor <NUM> coupled to a secure digital (SD) card <NUM> and a screen <NUM>, a Bluetooth module <NUM>, a wireless local area network (WLAN) module <NUM>, a Global Positioning System (GPS) module <NUM>, and a power supply <NUM>. The cellular baseband processor <NUM> communicates through the cellular RF transceiver <NUM> with the UE <NUM> and/or base station <NUM>/<NUM>. In one configuration, the apparatus <NUM> may be a modem chip and include just the cellular baseband processor <NUM>, and in another configuration, the apparatus <NUM> may be the entire UE (e.g., see the UE <NUM> of <FIG>) and include the additional modules of the apparatus <NUM>. The cellular baseband processor <NUM> may be a component of the base station <NUM> and may include the memory <NUM> and/or at least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM>. In one configuration, the apparatus <NUM> may be a modem chip and include just the cellular baseband processor <NUM>, and in another configuration, the apparatus <NUM> may be the entire base station (e.g., see the base station <NUM> of <FIG>) and include the additional modules of the apparatus <NUM>.

The communication manager <NUM> includes a signal reception component <NUM> that is configured to receive, from a transmitter, a signal comprising a sequence of shaped symbols, for example, as described in connection with <NUM> of <FIG>.

The communication manager <NUM> also includes a compression component <NUM> that is configured to compress the sequence of shaped symbols to output a sequence of compressed information bits, and where the compressing is based on the sequence of shaped symbols and a target probability mass function (PMF), for example, as described in connection with <NUM> of <FIG>.

The communication manager <NUM> also includes a discard component <NUM> that is configured to receive, from the transmitter, information about bits to discard, for example, as described in connection with <NUM> of <FIG>.

The communication manager <NUM> also includes an FEC decoding component <NUM> that is configured to perform FEC decoding of the sequence of shaped symbols output prior to the compressing, for example, as described in connection with <NUM> of <FIG>.

In one configuration, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, includes means for receiving, from a transmitter, a signal comprising a sequence of shaped symbols. The example apparatus <NUM> also includes means for compressing the sequence of shaped symbols to output a sequence of compressed information bits, wherein the compressing is based on the sequence of shaped symbols and a target PMF.

According to the claimed invention, the apparatus <NUM> also includes means for receiving, from the transmitter, information about postfix bits to discard.

In another configuration, the example apparatus <NUM> also includes means for performing FEC decoding of the sequence of shaped symbols output prior to the compressing.

The symbols on DL may be cyclic prefix (CP) orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. For slot configuration <NUM>, different numerologies µ <NUM> to <NUM> allow for <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> slots, respectively, per subframe. <FIG> provide an example of slot configuration <NUM> with <NUM> symbols per slot and numerology µ=<NUM> with <NUM> slots per subframe. The slot duration is <NUM>, the subcarrier spacing is <NUM>, and the symbol duration is approximately <NUM>. Within a set of frames, there may be one or more different bandwidth parts (BWPs) (see <FIG>) that are frequency division multiplexed. Each BWP may have a particular numerology.

The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) (e.g., <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> CCEs), each CCE including six RE groups (REGs), each REG including <NUM> consecutive REs in an OFDM symbol of an RB. A PDCCH within one BWP may be referred to as a control resource set (CORESET). A UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., common search space, UE-specific search space) during PDCCH monitoring occasions on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at greater and/or lower frequencies across the channel bandwidth. The physical broadcast channel (PBCH), which carries a master information block (MIB), may be logically grouped with the PSS and SSS to form a synchronization signal (SS)/PBCH block (also referred to as SS block (SSB)).

The PUCCH carries uplink control information (UCI), such as scheduling requests, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK) information (ACK / negative ACK (NACK)) feedback.

Aspects disclosed herein provide techniques for improving the spectral efficiency and achievable information rate for communication over a channel, e.g., an AWGN channel. For example, disclosed techniques utilize a distribution matcher that includes a decompresser to convert a sequence of information bits into a set of symbols. The sequence of information bits may be uniformly distributed, such as in <NUM> NR. The decompresser may generate the sequence of symbols based on a target probability mass function (PMF), such as a Maxwell-Boltzmann Distribution, and a symbol block length. The sequence of symbols may be transmitted to a receiver for processing to determine the transmitted information.

Claim 1:
A method of wireless communication at a wireless transmitter, comprising:
decompressing (<NUM>) a first sequence of information bits for wireless transmission to output a sequence of shaped symbols, wherein the decompression is based on a target symbol length and a target probability mass function, PMF;
compressing (<NUM>) the sequence of shaped symbols to output a second sequence of compressed information bits, wherein the compression is based on the target PMF; and
transmitting (<NUM>), to a receiver, a signal comprising the sequence of shaped symbols.