Abstract: This application provides an example timing advance update method, an example terminal, and an example base station. One example method includes receiving, by a terminal, an updated timing advance TA value and a beam cell identity of a beam cell in which the terminal is located that are sent by a base station. The example method also includes obtaining, by the terminal, corresponding TA compensation information based on the beam cell identity. The example method further includes performing, by the terminal, TA compensation in a TA update period based on the updated TA value and the TA compensation information. The example method also includes sending, by the terminal, uplink data by using a TA value obtained after TA compensation is performed.

Abstract: A random access method includes sending a random access preamble to a base station on a first time domain resource, obtaining an index value of the first time domain resource, obtaining an index difference between the first time domain resource and a second time domain resource, obtaining an index value of the second time domain resource by adding the index value of the first time domain resource and the index difference, obtaining a random access radio network temporary identifier (RA-RNTI) based on the index value of the second time domain resource, receiving a random access response (RAR) from the base station, and descrambling a cyclic redundancy check (CRC) code of the RAR using the RA-RNTI.

Abstract: This application provides a random access method and an apparatus. The method includes: receiving, by a terminal device, a broadcast signal; and sending, by the terminal device, a random access signal, where a preamble sequence in the random access signal includes K first symbols and Q second symbols, the first symbol and the second symbol are different from each other, K and Q are integers greater than or equal to 1, K+Q=NSEQ, and NSEQ is a quantity of symbols included in the preamble sequence.

Abstract: Embodiments of this application provide a parameter transmission method and an apparatus, and relate to the field of wireless communication technologies. In the method, the terminal device may receive first information. The first information may include a time parameter. The time parameter may be used to determine a timing offset. The timing offset includes a second timing offset, and the second timing offset indicates a delay of activation of configuration information. The terminal device determines a delay start duration of a random access response (RAR) window based on the second timing offset.

Abstract: In a communication method, to meet a requirement of a positioning service, a first communication apparatus obtains data to be processed, and determines a first frame structure that includes a communication time period and a positioning time period. A first switching time period is included between the communication time period and the positioning time period, a 1st time-domain symbol occupied by the first switching time period is consecutive to a last time-domain symbol occupied by the communication time period, and a last time-domain symbol occupied by the first switching time is consecutive to a 1st time-domain symbol occupied by the positioning time period. The first communication apparatus then processes the data based on the first frame structure.

Abstract: Embodiments of this application provide a method for coding in a wireless communication network. A communication device interleave a first bit sequence to obtain a first interleaved sequence having sequence number starting with a sequence number of 0, wherein the first bit sequence comprises bits for indicating timing, wherein the bits for indicating timing comprises a set of bits for indicating synchronization signal block index (SSBI); wherein the set of bits for indicating SSBI are placed in positions indicated by sequence numbers of 2, 3 and 5 in the first interleaved sequence. The devices add d first CRC bits on the first interleaved sequence to obtain a second bit sequence, interleave on the second bit sequence according to an interleave pattern to obtain a second interleaved sequence, and polar encode the second interleaved sequence to obtain the encoded sequence.

Abstract: The present disclosure relates to data transmission methods and apparatuses. In one example method, a receiving end obtains a transmission resource, and feeds back first information to a transmitting end based on the transmission resource. The first information is determined based on a channel state of a first channel, and the first information indicates whether retransmission is required or indicates whether a transmission mode is to be adjusted.

Abstract: This application relates to the field of wireless communications technologies, and discloses an encoding method and apparatus, to improve accuracy of reliability calculation and ordering for polarized channels. The method includes: obtaining a first sequence used to encode K to-be-encoded bits, where the first sequence includes sequence numbers of N polarized channels, the first sequence is same as a second sequence or a subset of the second sequence, the second sequence comprises sequence numbers of Nmax polarized channels, and the second sequence is the sequence shown in Sequence Q11 or Table Q11, K is a positive integer, N is a positive integer power of 2, n is equal to or greater than 5, K?N, Nmax=1024; selecting sequence numbers of K polarized channels from the first sequence; and performing polar code encoding on K the to-be-encoded bits based on the selected sequence numbers of the K polarized channels.

Abstract: Embodiments of this application provide a wireless communication method and an apparatus. The method includes: A first communication apparatus receives first information, where the first information indicates a determining threshold of a parameter in a first parameter set, and the first parameter set includes at least one of the following parameters: location information, delay information, a timing advance rate, a rate of the timing advance rate, a Doppler value, a Doppler rate, and remaining coverage time. The first communication apparatus determines, based on the first information, whether an access condition is met, and performs random access when the access condition is met. This avoids a random access failure in a current cell and re-access in a next cell due to random access performed when the condition is not met.

Abstract: A first communication apparatus obtains first ephemeris information of a second communication apparatus, where the first ephemeris information includes information about m parameters of n parameters in second ephemeris information, n is equal to 6, and m is a positive integer less than n, and the n parameters include a first location parameter, a first location parameter, and a first location parameter in first location information, and a first velocity parameter, a first velocity parameter, and a first velocity parameter in first velocity information. The first communication apparatus determines values of the n parameters in the second ephemeris information based on the first ephemeris information, where the values of the n parameters include values of the m parameters and values of remaining n-m parameters. The first communication apparatus communicates with the second communication apparatus based on the second ephemeris information.

Abstract: This application relates to a cell selection method and apparatus. In an example method, a terminal device performs measurement based on measurement configuration information of N cells and determines M candidate cells based on a measurement result. N is an integer greater than 0, and M is an integer greater than 0 and less than N. The example method further includes the terminal device selecting a target cell from the M candidate cells based on first information. The first information includes coverage information of at least one candidate cell in the M candidate cells.

Abstract: Embodiments of this application provides a communication method and a communication apparatus. The method includes: A second satellite device receives first indication information from a first satellite device, and obtains, based on the first indication information, a first timing pre-compensation value and/or a first frequency pre-compensation value corresponding to at least one first terminal. The second satellite device communicates with the at least one first terminal based on the first timing pre-compensation value and/or the first frequency pre-compensation value.

Abstract: Example communication methods and communication apparatus are described. One example method includes sending a first message by a first satellite to a second satellite. The first message includes information about a frequency reuse scheme. The information about the frequency reuse scheme includes basic unit information. The basic unit information includes central point locations and frequency information of at least N?1 beams. Herein, N is a frequency reuse factor of the first satellite. At least N?1 different pieces of frequency information exist in the frequency information that is of the at least N?1 beams and that is included in the basic unit information. In addition, N is a positive integer greater than or equal to 3.

Abstract: An uplink signal sending and receiving method includes that a first communication apparatus obtains a first timing advance (TA) change rate, and sends an uplink signal in a plurality of first time periods. There is a first time interval between the plurality of first time periods to compensate for a time synchronization drift. A length of the first time interval and a location of the first time interval between the plurality of first time periods are determined based on the first TA change rate, and the first TA change rate is a TA change rate in a communication process of the first communication apparatus.

Abstract: This application provides a method for processing a round trip delay, a related apparatus, and a readable storage medium, and pertains to the field of communications technologies. The method includes: receiving a delay quantization parameter of a common round trip delay (RTD), where the delay quantization parameter includes a first quantization parameter, and the first quantization parameter is used to indicate a height-related delay; and obtaining the common RTD based on the delay quantization parameter. The height-related delay is indicated by using the first quantization parameter, so that the common RTD is obtained based on the first quantization parameter.

Abstract: Embodiments of this application disclose a data transmission method, apparatus, and system, and relate to the communication field. This can flexibly configure a HARQ process to improve a data transmission throughput. A specific solution is: A network device sends a first transport block and a first identifier to a terminal. The first identifier is used to indicate whether to switch, from non-hybrid automatic repeat request HARQ transmission to HARQ transmission, a HARQ process in which the first transport block is located. The first identifier is occupied when the HARQ process uses the HARQ transmission. The terminal receives the first transport block and the first identifier from the network device. The first identifier is used to indicate whether to switch, from the non-hybrid automatic repeat request HARQ transmission to the HARQ transmission, the HARQ process in which the first transport block is located.

Abstract: A method includes: A transmit end obtains P QAM symbols; the transmit end performs IDWT or DWT on the P QAM symbols, to obtain a first signal matrix with N rows and M columns, and transposes the first signal matrix, to obtain a transposed first transpose matrix, where P, N, and M are all positive integers; and the transmit end outputs the transposed first transpose matrix. Correspondingly, a receive end obtains a second signal matrix with M rows and N columns; the receive end transposes the second signal matrix, to obtain a transposed second transpose matrix; and performs DWT or IDWT on the second transpose matrix, to obtain P QAM symbols.

Abstract: This application discloses a frequency compensation method and apparatus, to improve performance of frequency compensation. The method includes: determining a change rate of a Doppler frequency shift value based on a weighted change rate of a change rate of a timing advance TA, determining the Doppler frequency shift value based on the change rate of the Doppler frequency shift value, and performing frequency compensation based on the determined Doppler frequency shift value; or determining a frequency offset value based on the Doppler frequency shift value with reference to pre-compensation and based on a reference signal, to further determine a frequency offset value, and performing frequency compensation based on the frequency offset value.

Abstract: Example beam hopping methods and apparatus are described. In one example method, a first satellite sends a communication signal to a first area by using a first beam, where the communication signal is used by the first satellite to communicate with a terminal device in the first area, and the first area belongs to an area covered by the first satellite. The first satellite sends a positioning signal to a second area by using a second beam, where the positioning signal is used by a terminal device in the second area for positioning measurement.

Abstract: Embodiments of this application provide a channel matrix determining method, an apparatus, and a system, relating to the field of communication technologies, to resolve a technical problem that a manner in which a network device determines a precoding matrix based on an existing PMI indicator is not applicable to long-distance communication. The method includes: A terminal device obtains a plurality of reference signals, determines a first channel matrix based on the plurality of reference signals, and feeds back, to a network device, first information indicating some channel elements in the first channel matrix. The terminal device may further receive a downlink signal determined based on the first information and sent by the network device. A channel element in the some channel elements is determined based on signal strength and/or a time-frequency resource of the reference signal.