Title of Invention: Method and device in UE and base station used for channel coding Abstract: The present disclosure discloses a method and a device in a User and a base station used for channel coding. A first node determines a first bit block; performs channel coding; and transmits a first radio signal. Bits in the first bit block are used to generate bits in a second bit block. The bits in the first bit block and in the second bit block are used for an input to the channel coding, an output after the channel coding is used to generate the first radio signal. Channel coding is based on a polar code. A sub-channel occupied by a target first type bit is related to the number of bits in the second bit block related to the target first type bit. The target first type bit belongs to the first bit block. The disclosure can improve decoding performance of polar codes and reduce complexity of decoding. Detailed Description: Part general_description_paragraphs: Part CROSS-REFERENCE TO RELATED APPLICATION: This application is a continuation of International Application No. PCT/CN2018/071701, filed Jan. 8, 2018, claiming the priority benefit of Chinese Patent Application Serial Number 201710012223.3, filed on Jan. 9, 2017, and Chinese Patent Application Serial Number 201710045440.2, filed on Jan. 22, 2017, the full disclosure of which is incorporated herein by reference. Part BACKGROUND: Part Technical Field: The present disclosure relates to transmission schemes for radio signals in wireless communication systems, and in particular to a method and a device of transmission for channel coding. Part Related Art: Polar Codes are coding schemes first proposed by Professor Erdal Arikan from University of Birken in Turkey in 2008, which may realize the code construction method of the capacity of a symmetrical Binary input Distributed Memoryless Channel (B-DMC). At the 3rd Generation Partner Project (3GPP) RAN1#87 conference, the 3GPP determined the use of a Polar code scheme as a control channel coding scheme of the 5G Enhanced Mobile Broadband (eMBB) scenario. In the traditional Long Term Evolution (LTE) system, Cyclic Redundancy Check (CRC) has specific functions of error check and target receiver identification. As for polar codes, some 3GPP papers (for example, R1-1611254) have designed special check bits for polar codes to ensure that these polar codes can be used for pruning in channel decoding. Part SUMMARY: The inventors have found through researches that since different sub-channels of polar codes correspond to different channel capacities, information bits mapped to different sub-channels may experience varied Bit Error Rate (BERs), therefore, how redundant bits can be effectively utilized to improve decoding performance becomes a problem needed to be solved. In view of the above problem, the present disclosure provides a solution. It should be noted that, in the case of no conflict, the embodiments of the present disclosure and the characteristics in the embodiments may be combined with each other arbitrarily. For example, embodiments in a first node of the present disclosure and the characteristics in the embodiments may be applied to a second node, and vice versa. The present disclosure discloses a method in a first node for wireless communication, comprising: determining a first bit block; performing channel coding; and transmitting a first radio signal; wherein bits in the first bit block are used to generate bits in a second bit block; the bits in the first bit block and the bits in the second bit block are both used for an input to the channel coding, an output after the channel coding is used to generate the first radio signal; the channel coding is based on a polar code; for the channel coding, a sub-channel occupied by a target first type bit is related to at least one of a number of bits in the second bit block related to the target first type bit, or numbers of bits in K first type bit sets; the target first type bit belongs to the first bit block, the K first type bit sets respectively correspond to K second type bits, the K second type bits are all bits in the second bit block related to the target first type bit, for any given second type bit in the K second type bits, all bits in the first bit block used to generate the given second type bit constitute a first type bit set in the K first type bit sets corresponding to the given second type bit; the K is a positive integer. In one embodiment, the above method is advantageous in that redundancy of check bits related to the target first type bit can be determined based on transmission reliability of the sub-channel occupied by the target first type bit. By offering Unequal Error Protection to bits on different sub-channels, bits transmitted on a sub-channel with weaker reliability can be subjected to stronger error protection to improve transmission reliability thereof. In one embodiment, the sub-channel refers to a position in an input bit sequence of Arikan polar encoder. In one subembodiment of the above embodiment, an output after the input bit sequence is multiplied by a polar coding matrix is the output after the channel coding. The polar coding matrix is acquired as a product of a bit reversal permutation matrix and a first matrix, the first matrix is the n-th Kronecker power of a kernel matrix, the n is the logarithm of a length of the input bit sequence with base 2, the kernel matrix is a matrix with 2 rows and 2 columns, wherein two elements in a first row are 1 and 0, respectively, and other two elements in a second row are both 1. In one embodiment, the phrase that the sub-channel occupied by the target first type bit is related to at least one of a number of bits in the second bit block related to the target first type bit, or numbers of bits in K first type bit sets refers to: a channel capacity of a sub-channel occupied by the target first type bit is related to at least one of a number of bits in the second bit block related to the target bit or numbers of bits in K first type bits sets. In one embodiment, the capacity of the sub-channel is: an upper bound of information rate of reliable transmission on the sub-channel. In one embodiment, part of the bits in the first bit block are not related to the bits in the second bit block. In one embodiment, the first bit block is generated on a physical layer of the first node. In one embodiment, the first node is a base station, the first node generates the first bit block based on a result of scheduling. In one embodiment, the first node is a UE, the first node generates the first bit block based on scheduling of a base station. In one embodiment, for any bit in the second bit block, the any bit is equal to a sum of a positive integer number of bit(s) in the first bit block subjected to mod 2. In one embodiment, for any bit in the second bit block, the any bit is acquired after a sum of a positive integer number of bit(s) in the first bit block is subjected to mod 2 and then to Xor operation with a corresponding bit in a scrambling sequence. In one embodiment, the second bit block is not related to bits other than the first bit block. In one embodiment, the input to the channel coding includes all bits in the first bit block, all bits in the second bit block and all bits in a third bit block. Values of all bits in the third bit block are pre-set. In one subembodiment of the above embodiment, all bits in the third bit block are 0, respectively. In one subembodiment of the above embodiment, the bits in the third bit block are related to an identifier of the first node. In one subembodiment of the above embodiment, an identifier of the first node is used to generate the bits in the third bit block. In one subembodiment of the above embodiment, the bits in the third bit block are related to an identifier of a target receiver of the first radio signal. In one subembodiment of the above embodiment, the identifier of the target receiver of the first radio signal is used to generate the bits in the third bit block. In one embodiment, the first radio signal is transmitted on a physical layer control channel (i.e., a physical layer channel that cannot be used for transmitting physical layer data). In one embodiment, the first radio signal is transmitted on a physical layer data channel (i.e., a physical layer channel that can be used for bearing physical layer data). In one embodiment, the first node is a UE. In one subembodiment of the above embodiment, the first radio signal is transmitted on a Physical UplinkControl Channel (PUCCH). In one subembodiment of the above embodiment, the first radio signal is transmitted on a Physical Uplink Shared CHannel (PUSCH). In one embodiment, the first node is a base station. In one subembodiment of the above embodiment, the first radio signal is transmitted on a Physical Downlink Shared CHannel (PDSCH). In one subembodiment of the above embodiment, the first radio signal is transmitted on a Physical DownlinkControl Channel (PDCCH). In one embodiment, the first radio signal is an output after the output of the channel coding is sequentially subjected to Channel Coding, Scrambling, a Modulation Mapper, a Layer Mapper, Precoding, a Resource Element Mapper and broadband symbol generation. In one embodiment, the first radio signal is an output after the output of the channel coding is sequentially subjected to scrambling, a Modulation Mapper, a Layer Mapper, a transform precoder, Precoding, a Resource Element Mapper and broadband symbol generation. In one embodiment, the broadband symbol is an Orthogonal Frequency Division Multiplexing (OFDM) symbol. In one embodiment, the broadband symbol is a Filter Bank Multi Carrier (FBMC) symbol. Specifically, according to one aspect of the present disclosure, wherein the higher the number of the bits in the second bit block related to the target first type bit is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the higher the number of the bits in the second bit block related to the target first type bit is, the more a Bit Error Rate (BER) of the target first type bit will be reduced. As a result, the target first type bit should be mapped to a sub-channel with lower channel capacity so as to average BERs corresponding to the bits in the first bit block. In one embodiment, a channel capacity of a sub-channel occupied by a first given bit is less than a channel capacity of a sub-channel occupied by a second given bit, the number of bits in the second bit block related to the first given bit is greater than the number of bits in the second bit block related to the second given bit. Specifically, according to one aspect of the present disclosure, wherein the less a sum of the numbers of the bits in the K first type bit sets is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the K is equal to 1. In one embodiment, the K is greater than 1. In one embodiment, the K remains unchanged in the above aspect. In one embodiment, given that other conditions are the same, the less a sum of the numbers of the bits in the K first type bit sets is, the more a BER of the target first type bit will be reduced. As a result, the target first type bit should be mapped to a sub-channel with lower channel capacity so as to average BERs corresponding to the bits in the first bit block. In one embodiment, a sum of numbers of bits in K1 first type bit sets is less than a sum of number of bits in K2 first type bit sets. The K1 first type bit sets respectively correspond to K1 second type bits, the K1 second type bits are all bits in the second bit block related to a first given bit. The K2 first bit sets respectively correspond to K2 second type bits, the K2 second type bits are all bits in the second bit block related to a second given bit. The K1 and the K2 are positive integers, respectively. A channel capacity of a sub-channel occupied by the first given bit is smaller than a channel capacity of a sub-channel occupied by the second given bit. The first given bit and the second given bit both belong to the first bit block. In one embodiment, the K1 is equal to the K2. Specifically, according to one aspect of the present disclosure, wherein the greater a sum of reciprocals of the numbers of the bits in the K first type bit sets is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the greater a sum of K rational numbers is, the lower the channel capacity corresponding to the sub-channel occupied by the target first type bit will be. The K rational numbers respectively correspond to the K first type bit sets, any rational number of the K rational numbers is a reciprocal of a number of bits in a corresponding first type bit set. In one embodiment, given that other conditions are the same, the greater a sum of reciprocals of the numbers of the bits in the K first type bit sets is, the more a BER of the target first type bit will be reduced. As a result, the target first type bit should be mapped to a sub-channel with lower channel capacity so as to average BERs corresponding to the bits in the first bit block. In one embodiment, the K remains unchanged in the above aspect. In one embodiment, a sum of reciprocals of numbers of bits in K1 first type bit sets is greater than a sum of reciprocals of numbers of bits in K2 first type bit sets. The K1 first type bit sets respectively correspond to the K1 second type bits, the K1 second type bits are all bits in the second bit block related to a first given bit. The K2 first bit sets respectively correspond to K2 second type bits; the K2 second type bits are all bits in the second bit block related to a second given bit. The K1 and the K2 are positive integers, respectively. A channel capacity of a sub-channel occupied by the first given bit is smaller than a channel capacity of a sub-channel occupied by the second given bit. The first given bit and the second given bit both belong to the first bit block. In one embodiment, the K1 is equal to the K2. Specifically, according to one aspect of the present disclosure, wherein the first bit block comprises a first bit sub-block and a second bit sub-block, a CRC bit block of the first bit sub-block is used to generate the second bit sub-block. In one embodiment, the first bit sub-block and the second bit sub-block constitute the first bit block. In one embodiment, the second bit sub-block is a CRC bit block of the first bit sub-block. In one embodiment, the second bit sub-block is a bit block after the CRC bit block of the first bit sub-block is subjected to scrambling. In one embodiment, a scrambling sequence employed in the scrambling is related to an identifier of the first node. In one embodiment, the first node is a UE, an identifier of the first node is a Radio Network Temporary Identifier (RNTI). In one embodiment, the first node is a base station, an identifier of the first node is a Physical Cell Identifier (PCI). In one embodiment, a scrambling sequence employed in the scrambling is related to an identifier of a target receiver of the first radio signal. In one embodiment, the first node is a base station, an identifier of a target receiver of the first radio signal is an RNTI. In one embodiment, the CRC bit block of the first bit sub-block is an output after the first bit sub-block is subjected to a CRC cyclic generator polynomial. A polynomial consisting of the first bit sub-block and the CRC bit block of the first bit sub-block can be divided by the CRC cyclic generator polynomial on GF(2), namely, the polynomial consisting of the first bit sub-block and the CRC bit block of the first bit sub-block yields a remainder equal to 0 when divided by the CRC Cyclic Generator Polynomial. In one embodiment, a length of the second bit sub-block is one of 24, 16 and 8. In one embodiment, the length of the second bit sub-block is less than 8. In one embodiment, bits in the second bit sub-block are not related to the bits in the second bit block. In one embodiment, part of bits in the first bit sub-block are used to generate the bits in the second bit block, the other part of the bits in the first bit sub-block are not related to the bits in the second bit block. Specifically, according to one aspect of the present disclosure, wherein a channel capacity of a sub-channel mapped by any bit in a first bit set is greater than a channel capacity of a sub-channel mapped by any bit in a second bit set; the bits in the first bit block belong to the first bit set, the bits in the second bit block belong to the second bit set; or part of the bits in the first bit block belong to the first bit set, the other part of the bits in the first bit block and the bits in the second bit block belong to the second bit set. In one embodiment, the above method is advantageous in that Unequal Error Protection can be offered to the first bit set and the second bit set, so that important bits can be transmitted on sub-channels with higher reliability, thus improving the transmission quality of transmission of the first radio signal. In one embodiment, there does not exist a bit common to the first bit set and the second bit set. In one embodiment, any bit in the first bit block belongs to one of the first bit set and the second bit set, any bit in the second bit block belongs to one of the first bit set and the second bit set. In one embodiment, the input to the channel coding includes all bits in the first bit block, all bits in the second bit block and all bits in a third bit block. Values of all bits in the third bit block are pre-set. A channel capacity of a sub-channel mapped by any bit in the third bit block is smaller than a channel capacity of a sub-channel mapped by any bit in the second bit set. In one embodiment, the part of the bits in the first bit block and the other part of the bits in the first bit block constitute the first bit block. In one embodiment, the other part of the bits in the first bit block are used to generate the bits in the second bit block, the bits in the second bit block are not related to the part of the bits in the first bit block. In one embodiment, a channel capacity of a sub-channel occupied by any bit of the other part of the bits in the first bit block is greater than a channel capacity of a sub-channel occupied by any bit in the second bit block. Specifically, according to one aspect of the present disclosure, wherein a CRC bit block of the first bit block is used to generate the second bit block. In one embodiment, the second bit block is a CRC bit block of the first bit block. In one embodiment, the second bit block is a bit block after a CRC bit block of the first bit block is subjected to scrambling. In one embodiment, a scrambling sequence employed in the scrambling is related to an identifier of the first node. In one embodiment, the first node is a UE, an identifier of the first node is an RNTI. In one embodiment, the first node is a base station, an identifier of the first node is a PCI. In one embodiment, a scrambling sequence employed in the scrambling is related to an identifier of a target receiver of the first radio signal. In one embodiment, the first node is a base station, an identifier of a target receiver of the first radio signal is an RNTI. In one embodiment, the CRC bit block of the first bit block is an output after the first bit block is subjected to a CRC cyclic generator polynomial. A polynomial consisting of the first bit block and the CRC bit block of the first bit block can be divided by the CRC cyclic generator polynomial on GF(2), namely, the polynomial consisting of the first bit block and the CRC bit block of the first bit block yields a remainder equal to 0 when divided by the CRC Cyclic Generator Polynomial. In one embodiment, the other part of the bits in the first bit block are used to generate the second bit block. In one embodiment, the second bit block is a CRC bit block of the other part of the bits in the first bit block. In one embodiment, the second bit block is a bit block after a CRC bit block of the other part of the bits in the first bit block is subjected to scrambling. In one embodiment, the other part of the bits in the first bit block are a subset of the first bit sub-block. In one subembodiment of the above embodiment, bits in the first bit sub-block not belonging to the other part of bits in the first bit block are unrelated to bits in the second bit block. Specifically, according to one aspect of the present disclosure, wherein the first node is a base station, the first bit block comprises downlink control information (DCI); or the first node is a UE, the first bit block comprises uplink control information (UCI). In one embodiment, the DCI indicates at least one of corresponding statistics, which are time domain resources occupied, frequency domain resources occupied, a Modulation and Coding Scheme (MCS), a Redundancy Version (RV), a New Data Indicator (NDI), and a Hybrid Automatic Repeat reQuest (HARQ) process number. In one embodiment, the UCI indicates at least one of HARQ-Acknowledgement (HARQ-ACK), Channel State Information (CSI), a Scheduling Request (SR), or a CSI-RS resource indication (CRI). The present disclosure discloses a method in a second node for wireless communication, comprising: receiving a first radio signal; performing channel decoding; and recovering a first bit block; wherein channel coding corresponding to the channel decoding is based on a polar code; bits in the first bit block are used to generate bits in a second bit block; the bits in the first bit block and the bits in the second bit block are both used for an input to the channel coding, an output after the channel coding is used to generate the first radio signal; for the channel coding, a sub-channel occupied by a target first type bit is related to at least one of a number of bits in the second bit block related to the target first type bit, or numbers of bits in K first type bit sets; the target first type bit belongs to the first bit block, the K first type bit sets respectively correspond to K second type bits, the K second type bits are all bits in the second bit block related to the target first type bit, for any given second type bit in the K second type bits, all bits in the first bit block used to generate the given second type bit constitute a first type bit set in the K first type bit sets corresponding to the given second type bit; the K is a positive integer. In one embodiment, the second node is a base station, the first node is a UE. In one embodiment, the second node is a UE, the first node is a base station. In one embodiment, an output after the channel decoding is used to recover the first bit block. Specifically, according to one aspect of the present disclosure, wherein the higher the number of the bits in the second bit block related to the target first type bit is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. Specifically, according to one aspect of the present disclosure, wherein the less a sum of the numbers of the bits in the K first type bit sets is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. Specifically, according to one aspect of the present disclosure, wherein the greater a sum of reciprocals of the numbers of the bits in the K first type bit sets is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. Specifically, according to one aspect of the present disclosure, wherein the first bit block comprises a first bit sub-block and a second bit sub-block, a CRC bit block of the first bit sub-block is used to generate the second bit sub-block. Specifically, according to one aspect of the present disclosure, wherein a channel capacity of a sub-channel mapped by any bit in a first bit set is greater than a channel capacity of a sub-channel mapped by any bit in a second bit set; the bits in the first bit block belong to the first bit set, the bits in the second bit block belong to the second bit set; or part of the bits in the first bit block belong to the first bit set, the other part of the bits in the first bit block and the bits in the second bit block belong to the second bit set. Specifically, according to one aspect of the present disclosure, wherein the channel decoding is used to determine P reference values, the P reference values respectively correspond to bits in a target bit group, the target bit group consists of the bits in the first bit block and the bits in the second bit block, a sum of a number of the bits in the first bit block and a number of the bits in the second bit block is the P; reference values in the P reference values that correspond to the bits in the second bit block are used for pruning in the channel decoding; reference values in the P reference values that correspond to bits in the second bit sub-block are used to determine whether the first bit block is correctly received; the P is a positive integer greater than 1. In one embodiment, the above method is advantageous in that the bits in the second bit block can be used to improve decoding accuracy in the channel decoding and to reduce complexity of decoding; the bits in the second bit sub-block can be used to realize traditional CRC functions, which is to determine whether the first bit block is correctly received, and to transmit an identifier of the first node or an identifier of a receiver of the first radio signal. Therefore, both pruning and traditional CRC functions will be realized. In one embodiment, the P reference values are (received) bits recovered from corresponding (transmitted) bits. In one embodiment, the P reference values are (received) soft bits recovered from corresponding (transmitted) bits. In one embodiment, the P reference values are Log Likelihood Ratios (LLRs) estimated for corresponding (transmitted) bits. In one embodiment, the pruning is used to reduce surviving search paths in the channel decoding based on Viterbi principle. In one embodiment, a given reference value is a reference value in the P reference values used for pruning. For the given reference value, bits corresponding to a pruned search path are related to a given second type bit, the given second type bit is a bit in the second bit block corresponding to the given reference value. In one subembodiment of the above embodiment, for the given reference value, bits corresponding to a pruned search path are used to generate the given second type bit. In one subembodiment of the above embodiment, for the given reference value, a sum of bits corresponding to a pruned search path is subjected to mod 2 before acquiring the given second type bit. In one subembodiment of the above embodiment, for the given reference value, a sum of bits corresponding to a pruned search path is subjected to mod 2 and then to Xor operation with a corresponding bit in a scrambling sequence before acquiring the given second type bit. In one embodiment, reference values in the P reference values that correspond to bits in the second bit sub-block are used to indicate an identifier of a target receiver of the first radio signal. In one embodiment, reference values in the P reference values that correspond to bits in the second bit sub-block are used to indicate an identifier of the first node. In one embodiment, reference values in the P reference values that correspond to bits in the second bit sub-block and reference values in the P reference values that correspond to bits in the first bit sub-block collectively pass CRC check, if the check result turns out to be correct, it is then determined that the first bit block is correctly recovered; otherwise, it is determined that the first bit block is not recovered correctly. Specifically, according to one aspect of the present disclosure, wherein a CRC bit block of the first bit block is used to generate the second bit block. Specifically, according to one aspect of the present disclosure, wherein the second node is a UE, the first bit block comprises DCI; or the second node is a base station, the first bit block comprises UCI. The present disclosure discloses a device in a first node for wireless communication, comprising: a first processor, generating a first bit block; a second processor, performing channel coding; and a first transmitter, transmitting a first radio signal; wherein bits in the first bit block are used to generate bits in a second bit block; the bits in the first bit block and the bits in the second bit block are both used for an input to the channel coding, an output after the channel coding is used to generate the first radio signal; the channel coding is based on a polar code; for the channel coding, a sub-channel occupied by a target first type bit is related to at least one of a number of bits in the second bit block related to the target first type bit, or numbers of bits in K first type bit sets; the target first type bit belongs to the first bit block, the K first type bit sets respectively correspond to K second type bits, the K second type bits are all bits in the second bit block related to the target first type bit, for any given second type bit in the K second type bits, all bits in the first bit block used to generate the given second type bit constitute a first type bit set in the K first type bit sets corresponding to the given second type bit; the K is a positive integer. In one embodiment, the device in the above first node is characterized in that the higher the number of the bits in the second bit block related to the target first type bit is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the device in the above first node is characterized in that the less a sum of the numbers of the bits in the K first type bit sets is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the device in the above first node is characterized in that the greater a sum of reciprocals of the numbers of the bits in the K first type bit sets is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the device in the above first node is characterized in that the first bit block comprises a first bit sub-block and a second bit sub-block, a CRC bit block of the first bit sub-block is used to generate the second bit sub-block. In one embodiment, the device in the above first node is characterized in that a channel capacity of a sub-channel mapped by any bit in a first bit set is greater than a channel capacity of a sub-channel mapped by any bit in a second bit set; the bits in the first bit block belong to the first bit set, the bits in the second bit block belong to the second bit set; or part of the bits in the first bit block belong to the first bit set, the other part of the bits in the first bit block and the bits in the second bit block belong to the second bit set. In one embodiment, the device in the above first node is characterized in that a CRC bit block of the first bit block is used to generate the second bit block. In one embodiment, the device in the above first node is characterized in that the first node is a base station, the first bit block comprises DCI; or the first node is a UE, the first bit block comprises UCI. The present disclosure discloses a device in a second node for wireless communication, comprising: a first receiver, receiving a first radio signal; a third processor, performing channel decoding; and a fourth processor, recovering a first bit block; wherein channel coding corresponding to the channel decoding is based on a polar code; bits in the first bit block are used to generate bits in a second bit block; the bits in the first bit block and the bits in the second bit block are both used for an input to the channel coding, an output after the channel coding is used to generate the first radio signal; for the channel coding, a sub-channel occupied by a target first type bit is related to at least one of a number of bits in the second bit block related to the target first type bit, or numbers of bits in K first type bit sets; the target first type bit belongs to the first bit block, the K first type bit sets respectively correspond to K second type bits, the K second type bits are all bits in the second bit block related to the target first type bit, for any given second type bit in the K second type bits, all bits in the first bit block used to generate the given second type bit constitute a first type bit set in the K first type bit sets corresponding to the given second type bit; the K is a positive integer. In one embodiment, the device in the second node is characterized in that an output after the channel decoding is used to recover the first bit block. In one embodiment, the device in the second node is characterized in that the higher the number of the bits in the second bit block related to the target first type bit is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the device in the second node is characterized in that the less a sum of the numbers of the bits in the K first type bit sets is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the device in the second node is characterized in that the greater a sum of reciprocals of the numbers of the bits in the K first type bit sets is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the device in the second node is characterized in that the first bit block comprises a first bit sub-block and a second bit sub-block, a CRC bit block of the first bit sub-block is used to generate the second bit sub-block. In one embodiment, the device in the second node is characterized in that a channel capacity of a sub-channel mapped by any bit in a first bit set is greater than a channel capacity of a sub-channel mapped by any bit in a second bit set; the bits in the first bit block belong to the first bit set, the bits in the second bit block belong to the second bit set; or part of the bits in the first bit block belong to the first bit set, the other part of the bits in the first bit block and the bits in the second bit block belong to the second bit set. In one embodiment, the device in the second node is characterized in that the channel decoding is used to determine P reference values, the P reference values respectively correspond to bits in a target bit group, the target bit group consists of the bits in the first bit block and the bits in the second bit block, a sum of a number of the bits in the first bit block and a number of the bits in the second bit block is the P; reference values in the P reference values that correspond to the bits in the second bit block are used for pruning in the channel decoding; reference values in the P reference values that correspond to bits in the second bit sub-block are used to determine whether the first bit block is correctly received; the P is a positive integer greater than 1. In one embodiment, the method in the above second node is characterized in that a CRC bit block of the first bit block is used to generate the second bit block. In one embodiment, the method in the above second node is characterized in that the second node is a UE, the first bit block comprises DCI; or the second node is a base station, the first bit block comprises UCI. In one embodiment, the present disclosure has the following advantages over conventional schemes: CRC or one of other block codes is utilized as an outer code for a polar code, thus enhancing the decoding performance of the polar code; the redundancy of an information bit in an outer code is determined based on the transmission reliability of a sub-channel mapped by the information bit, so that Unequal Error Protection can be provided to information bits on different sub-channels, namely, an information bit transmitted on a sub-channel with weaker reliability can be subjected to stronger error protection in an outer code to improve transmission reliability thereof; the check bit of an outer code is used in the decoding process for pruning, so as to reduce complexity of decoding; traditional CRC functions are maintained, i.e., error check and target receiver identification. Part DESCRIPTION OF THE EMBODIMENTS: Part Embodiment 1: Embodiment 1 illustrates a flowchart of wireless transmission, as shown in FIG. 1. In FIG. 1, a base station N1 is a maintenance base station for a serving cell of a UE U2. The N1 transmits a first radio signal in step S11. The U2 receives a first radio signal in step S12. In Embodiment 1, bits in a first bit block are used by the N1 to generate bits in a second bit block. The bits in the first bit block and the bits in the second bit block are both used by the N1 for an input to channel coding, the input to the channel coding is used by the N1 to generate the first radio signal. The channel coding is based on a polar code; for the channel coding, a sub-channel occupied by a target first type bit is related to at least one of a number of bits in the second bit block related to the target first type bit, or numbers of bits in K first type bit sets. The target first type bit belongs to the first bit block, the K first type bit sets respectively correspond to K second type bits, the K second type bits are all bits in the second bit block related to the target first type bit, for any given second type bit in the K second type bits, all bits in the first bit block used to generate the given second type bit constitute a first type bit set in the K first type bit sets corresponding to the given second type bit. The K is a positive integer. The first radio signal is used by the U2 to generate an input to channel decoding, channel coding corresponding to the channel decoding is based on a polar code. An output after the channel decoding is used by the U2 to recover the first bit block. In one embodiment, the sub-channel refers to a position in an input bit sequence of Arikan polar encoder. In one subembodiment of the above embodiment, an output after the input bit sequence is multiplied by a polar coding matrix is the output after the channel coding. The polar coding matrix is acquired as a product of a bit reversal permutation matrix and a first matrix, the first matrix is the n-th Kronecker power of a kernel matrix, the n is the logarithm of a length of the input bit sequence with base 2, the kernel matrix is a matrix with 2 rows and 2 columns, wherein two elements in a first row are 1 and 0, respectively, and other two elements in a second row are both 1. In one embodiment, the phrase that the sub-channel occupied by the target first type bit is related to at least one of a number of bits in the second bit block related to the target first type bit, or numbers of bits in K first type bit sets refers to: a channel capacity of a sub-channel occupied by the target bit is related to at least one of a number of bits in the second bit block related to the target bit or numbers of bits in K first type bits sets. In one embodiment, the channel capacity of one sub-channel is: an upper bound of information rate of reliable transmission on the one sub-channel. In one embodiment, part of the bits in the first bit block are not related to the bits in the second bit block. In one embodiment, the first bit block is generated on a physical layer of the N1. The N1 generates the first bit block based on a result of scheduling. In one embodiment, the input to the channel coding includes all bits in the first bit block, all bits in the second bit block and all bits in a third bit block. Values of all bits in the third bit block are pre-set. In one subembodiment of the above embodiment, all the bits in the third bit block are 0. In one subembodiment of the above embodiment, the bits in the third bit block are related to an identifier of the U2. In one subembodiment of the above embodiment, an identifier of the U2 is used to generate the bits in the third bit block. In one subembodiment of the above embodiment, an identifier of the U2 is an RNTI. In one embodiment, the first radio signal is an output after the output of the channel coding is sequentially subjected to Channel Coding, Scrambling, a Modulation Mapper, a Layer Mapper, Precoding, a Resource Element Mapper and broadband symbol generation. In one embodiment, the broadband symbol is an OFDM symbol. In one embodiment, the broadband symbol is an FBMC symbol. In one embodiment, the second bit block is not related to bits other than the first bit block. In one embodiment, the higher the number of the bits in the second bit block related to the target first type bit is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the less a sum of the numbers of the bits in the K first type bit sets is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the greater a sum of reciprocals of the numbers of the bits in the K first type bit sets is, the lower a channel capacity corresponding to the sub-channel occupied by the target first type bit will be. In one embodiment, the first bit block comprises a first bit sub-block and a second bit sub-block, a CRC bit block of the first bit sub-block is used to generate the second bit sub-block. In one embodiment, a channel capacity of a sub-channel mapped by any bit in a first bit set is greater than a channel capacity of a sub-channel mapped by any bit in a second bit set. The bits in the first bit block belong to the first bit set, the bits in the second bit block belong to the second bit set; or part of the bits in the first bit block belong to the first bit set, the other part of the bits in the first bit block and the bits in the second bit block belong to the second bit set. In one embodiment, a CRC bit block of the first bit block is used to generate the second bit block. In one embodiment, the first bit block comprises DCI. In one subembodiment of the above embodiment, the DCI indicates at least one of corresponding statistics, which are time domain resources occupied, frequency domain resources occupied, an MCS, an RV, an NDI, and a HARQ process number. In one embodiment, the channel decoding is used by the U2 to determine P reference values, the P reference values respectively correspond to bits in a target bit group, the target bit group consists of the bits in the first bit block and the bits in the second bit block, a sum of a number of the bits in the first bit block and a number of the bits in the second bit block is the P. Reference values in the P reference values that correspond to the bits in the second bit block are used for pruning in the channel decoding. Reference values in the P reference values that correspond to bits in the second bit sub-block are used to determine whether the first bit block is correctly received. The P is a positive integer greater than 1. Part Embodiment 2: Embodiment 2 illustrates a flowchart of wireless transmission, as shown in FIG. 2. In FIG. 2, a base station N3 is a maintenance base station for a serving cell of a UE U4. The N3 receives a first radio signal in step S31. The U4 transmits a first radio signal in step S41. In Embodiment 2, bits in a first bit block are used by the U4 to generate bits in a second bit block. The bits in the first bit block and the bits in the second bit block are both used by the U4 for an input to channel coding, the input to the channel coding is used by the U4 to generate the first radio signal. The channel coding is based on a polar code; for the channel coding, a sub-channel occupied by a target first type bit is related to at least one of a number of bits in the second bit block related to the target first type bit, or numbers of bits in K first type bit sets. The target first type bit belongs to the first bit block, the K first type bit sets respectively correspond to K second type bits, the K second type bits are all bits in the second bit block related to the target first type bit, for any given second type bit in the K second type bits, all bits in the first bit block used to generate the given second type bit constitute
{'bibliographic_information': "{'country': 'US', 'doc-number': '16505735', 'kind': 'B2', 'date': '20190709', 'extension': '93', 'invention_title': 'Method and device in UE and base station used for channel coding'}", 'source_file': './grant/2022/ipg220322.xml', 'source_data': 'USPTO-Grant'}