CN109429354B

CN109429354B - Random access method and terminal

Info

Publication number: CN109429354B
Application number: CN201710775219.2A
Authority: CN
Inventors: 曹永照; 赵毅男; 吴凤娟; 胡小群; 张鹏; 周国华
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-08-31
Filing date: 2017-08-31
Publication date: 2021-05-18
Anticipated expiration: 2037-08-31
Also published as: WO2019042335A1; CN109429354A

Abstract

The embodiment of the invention provides a random access method and a terminal, relates to the field of communication, and can adjust TA of the terminal and increase the coverage area of a base station under the condition of high-frequency large subcarrier spacing. The method comprises the following steps: a terminal receives a first uplink Timing Advance (TA) sent by a base station and sends first uplink data to the base station according to the first TA; the terminal receives a receiving failure response sent by the base station, and updates the first TA to a second TA, wherein the second TA is larger than the first TA; the receiving failure response is used for indicating that the base station does not successfully receive the first uplink data; and the terminal sends second uplink data to the base station according to the second TA.

Description

Random access method and terminal

Technical Field

The embodiment of the invention relates to the field of communication, in particular to a random access method and a terminal.

Background

When the number of terminals is large, the simultaneous request of different terminals to access the base station can cause collision between the terminals, and the random access technology can well solve the collision between users. Specifically, the base station broadcasts a system message, and each terminal receives the system message and determines a preamble according to the system message. Then, the terminal sends a preamble to the base station through a Physical Random Access Channel (PRACH), and the base station measures an uplink Timing Advance (TA) of the terminal according to the preamble sent by the terminal, and then sends the TA to the terminal. The terminal determines the starting time of uplink transmission according to the received TA and starts uplink transmission at the starting time. And once the base station successfully demodulates and decodes the uplink data sent by the terminal, sending a confirmation message to the terminal to indicate that the uplink data sent by the terminal is successfully transmitted.

Typically, the base station takes the symbol duration as the time granularity for estimating TA. If the transmission delay of the lead code sent by the terminal to the base station exceeds the symbol duration T under the communication system, the TA determined by the base station is inaccurate. Generally, a transmission delay (RTD) per 1km when a terminal transmits data to a base station is 6.7 μ s, so that the base station can estimate a TA of the terminal at maximum distance from the base station (T/6.7) km. The coverage area of the serving cell of the base station is a range with a radius of (T/6.7) km around the base station. That is, in the terminals out of the cell coverage, the time it takes for the base station to transmit the preamble is longer than 1 symbol duration, so the base station cannot accurately calculate the TA of these terminals.

For example, in LTE, the PRACH subcarrier spacing is 1.25KHZ, the time duration of one symbol in the time domain is about 1/1.25 ═ 0.8s, i.e. 800 μ s, and the base station can accurately estimate the TA of the terminal within the cell coverage radius (800 μ s/6.7 μ s ═ 120 km).

In a New Radio (NR) system, the PRACH subcarrier spacing may become large (for example, the new NR system supports the PRACH subcarrier spacing of 120kHz), and the symbol duration becomes small, so the coverage radius of the serving cell of the base station becomes small. That is, the base station can only accurately calculate the TA of the terminal within a small range, and for a large number of terminals outside the coverage of the serving cell of the base station, the base station cannot accurately estimate the TA of the terminals, so that the terminals cannot be successfully accessed according to the TA issued by the base station in the random access stage.

Disclosure of Invention

The application provides a random access method and a terminal, which can adjust TA of the terminal and increase the coverage of a base station under the condition of high-frequency large subcarrier spacing.

In order to achieve the purpose, the technical scheme is as follows:

in a first aspect, a random access method is disclosed, which includes: the terminal receives a first TA sent by the base station and sends first uplink data to the base station according to the first TA; once the first TA calculated by the base station for the terminal is inaccurate, the base station cannot successfully receive the first uplink data sent by the terminal, and then the base station replies a reception failure response to the terminal to indicate that the base station does not successfully receive the first uplink data. And the terminal receives a receiving failure response sent by the base station, updates the first TA to a second TA, wherein the second TA is larger than the first TA, and the terminal sends second uplink data to the base station according to the second TA.

In the random access method provided by the embodiment of the invention, after the terminal sends the uplink data, if a reception failure response sent by the base station is received, the terminal can adjust the TA to increase the TA, and the second uplink data sent according to the larger TA can possibly reach the base station in the CP.

With reference to the first aspect, in a first possible implementation manner of the first aspect, the method further includes: the method comprises the steps that a terminal receives a timing advance adjusting coefficient K sent by a base station, wherein the K is an integer which is more than or equal to 1 and less than or equal to Q, and the Q is a difference value between the upper limit of the number of symbols occupied by random access lead codes supported under a communication system where the terminal and the base station work and the number of symbols occupied by the lead codes configured at present by the base station.

That is, if the first TA calculated by the base station for the terminal is smaller, the terminal may be instructed to increase the TA by the advance adjustment coefficient K. Specifically, the base station supports that the random access preamble occupies S symbols at most, that is, the base station can accurately calculate the TA of the terminal within kilometer of the base station (S × t/6.7), where t is a symbol duration. Assume that the length of the random access preamble currently configured by the base station is P symbols, that is, the base station can currently accurately calculate the TA of the terminal within kilometer of the base station (P × t/6.7). If the time of the first uplink data sent by the terminal according to the first TA is not within the cyclic prefix and the uplink data is not successfully received by the base station, the terminal may be considered to be out of the kilometer range from the base station (P × t/6.7), but if the terminal is within the kilometer range from the base station (S × t/6.7), the base station may calculate an accurate TA for the terminal, and only needs to increase the symbol duration on the basis of the first TA, and the first TA can only increase (S-P ═ Q) symbols at most.

With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the updating the first TA to the second TA specifically includes: determining the second TA as N₀+ t × K, where N₀For the first TA, t is the traffic for the base station and the terminal to workThe time length of one symbol in the signaling format.

The terminal can increase K symbol durations on the basis of the first TA, and the second uplink data sent according to the increased TA may fall within the cyclic prefix, so that the second uplink data can be successfully received by the base station, and the probability of successful access of the terminal is increased. In addition, the base station directly indicates the terminal to adjust the TA through the K through the downlink message, so that the problem that the terminal adjusts the TA for multiple times and sends uplink data for multiple times to cause interference to other terminals in the cell is avoided.

With reference to the first aspect or any one of the foregoing possible implementation manners of the first aspect, in a third possible implementation manner of the first aspect, the updating the first TA to the second TA specifically includes: and receiving a second TA sent by the base station, and updating the first TA into the received second TA. Here, the second TA is a first TA + N × t, t is a time length of one symbol in a communication system in which the base station and the terminal operate, N is an integer greater than or equal to 0 and less than or equal to Q, and Q is a difference between an upper limit of a number of symbols occupied by a random access preamble supported by the terminal and the communication system in which the base station operates and a number of symbols occupied by a preamble currently configured by the base station.

That is, the base station directly indicates a TA to the terminal, and the terminal may determine the uplink transmission time using the received TA to transmit uplink data. The second uplink data sent according to the second TA may fall within the cyclic prefix, and the second uplink data may be successfully received by the base station, thereby increasing the probability of successful access of the terminal. In addition, the base station directly indicates a TA to the terminal through the downlink message, so that the interference of the terminal to other terminals in the cell caused by the repeated TA adjustment and the repeated uplink data transmission of the terminal is avoided.

With reference to the first aspect or any one of the foregoing possible implementation manners of the first aspect, in a fourth possible implementation manner of the first aspect, the sending, by the terminal to the base station according to the second TA specifically includes: and determining a first uplink transmission time according to the second TA, and transmitting second uplink data at the first uplink transmission time.

That is, the terminal may determine the time to transmit the second uplink data according to the time of last receiving the downlink message and the second TA. For example, the first uplink transmission time is the time of last receiving the downlink message + scheduling delay-2 × the second TA.

With reference to the first aspect or any one of the foregoing possible implementations of the first aspect, in a fifth possible implementation of the first aspect, the updating the first TA to the second TA specifically includes: according to N₀+ t × Q determines Q uplink timing advances, the second TA comprises Q uplink timing advances, where Q ∈ [1, Q]Q is an integer, and Q is a difference value between the upper limit of the number of symbols occupied by the random access lead code supported under the communication system in which the terminal and the base station work and the number of symbols occupied by the lead code currently configured by the base station; wherein N is₀For the first TA, t is the time length of one symbol in the communication system in which the base station and the terminal operate.

That is, the terminal may determine N₀+t×1、N₀+t×2……N₀Each of the Q TAs + txq is greater than the first TA, and the second uplink data sent according to the greater TA may fall within the cyclic prefix, so that the second uplink data is successfully received by the base station, thereby increasing the probability of successful access of the terminal.

With reference to the first aspect or any one of the foregoing possible implementation manners of the first aspect, in a sixth possible implementation manner of the first aspect, the sending, by the terminal to the base station according to the second TA specifically includes: according to ith uplink timing advance N in Q uplink timing advances₀Determining a first uplink sending time by + txi, and sending second uplink data at the first uplink sending time; wherein i is more than or equal to 1 and less than or equal to Q; if the terminal receives the receiving failure response sent by the base station, the N is used₀+ t × (i +1) determines the second uplink transmission time, and transmits the second uplink data at the second uplink transmission time.

That is, the terminal sends uplink data for multiple times according to different TAs, the TA sending the uplink data each time increases a symbol duration compared with the TA sending the uplink data last time, if a reception failure response sent by the base station is received after the terminal sends the uplink data for a certain time, it indicates that the uplink data sent this time is not successfully received by the base station, and the TA needs to be adjusted, and the terminal increases the TA by a symbol duration. In the implementation mode, the base station does not need to instruct the terminal how to adjust the TA through instructions, the TA can be automatically adjusted, the signaling overhead of the base station is saved, meanwhile, the second uplink data sent according to the larger TA may fall into the cyclic prefix, and the second uplink data can be successfully received by the base station, so that the probability of successful access of the terminal is increased.

With reference to the first aspect or any one of the foregoing possible implementations of the first aspect, in a seventh possible implementation of the first aspect, before the terminal receives the first TA sent by the base station, the method further includes: receiving a system message sent by a base station, wherein the system message comprises a root sequence index number and/or format configuration information of a random access lead code; determining a random access lead code according to the index number of the root sequence and/or the format configuration information of the random access lead code; the random access preamble is transmitted to the base station.

The terminal determines a random access preamble according to the system message broadcast by the base station, and then sends the random access preamble to the base station, so that the base station can determine the first TA according to the time when the random access preamble sent by the terminal is successfully received.

In a second aspect, a terminal is disclosed, comprising: a receiving unit, configured to receive a first uplink timing advance TA sent by a base station; a sending unit, configured to send first uplink data to the base station according to the first TA received by the receiving unit; the receiving unit is further configured to receive a reception failure response sent by the base station; the receiving failure response is used for indicating that the base station does not successfully receive the first uplink data; an updating unit, configured to update the first TA to a second TA, where the second TA is greater than the first TA; the sending unit is further configured to send second uplink data to the base station according to the second TA.

With reference to the second aspect, in a first possible implementation manner of the second aspect, the receiving unit is further configured to receive a timing advance adjustment coefficient K sent by the base station, where K is an integer greater than or equal to 1 and less than or equal to Q, and Q is a difference between an upper limit of a number of symbols occupied by a random access preamble supported in a communication system in which the terminal and the base station operate and a number of symbols occupied by a preamble currently configured by the base station.

With reference to the second aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner of the second aspect, the updating unit is specifically configured to determine that the second TA is N₀+ t × K, where N₀For the first TA, t is the time length of one symbol in the communication system in which the base station and the terminal operate.

With reference to the second aspect or any one of the foregoing possible implementation manners of the first aspect, in a third possible implementation manner of the second aspect, the receiving unit is further configured to receive a second TA sent by the base station; the updating unit is specifically configured to update the first TA to the received second TA.

With reference to the second aspect or any one of the foregoing possible implementation manners of the first aspect, in a fourth possible implementation manner of the second aspect, the terminal further includes a determining unit, where the determining unit is configured to determine a first uplink sending time according to the second TA; the sending unit is specifically configured to send the second uplink data at the first uplink sending time.

With reference to the second aspect or any one of the foregoing possible implementations of the first aspect, in a fifth possible implementation of the second aspect, the updating unit is specifically configured to, according to N, update the update unit₀+ t × Q determines Q uplink timing advances, the second TA comprises Q uplink timing advances, where Q ∈ [1, Q]Q is an integer, and Q is a difference value between the upper limit of the number of symbols occupied by the random access lead code supported under the communication system in which the terminal and the base station work and the number of symbols occupied by the lead code currently configured by the base station; wherein N is₀For the first TA, t is the time length of one symbol in the communication system in which the base station and the terminal operate.

With reference to the second aspect or any one of the foregoing possible implementations of the first aspect, in a sixth possible implementation of the second aspect, the determining unit is specifically configured to determine, according to an ith uplink timing advance N of the Q uplink timing advances₀+ txi determines a first uplink transmission time; the sending unit is used for sending second uplink data at the first uplink sending time; wherein, i is more than or equal to 1 and less than or equal toQ; the receiving unit is used for receiving a receiving failure response sent by the base station; a determination unit for determining based on N₀+ t (i +1) determining a second uplink transmission time; the transmitting unit is configured to transmit the second uplink data at the second uplink transmission time.

With reference to the second aspect or any one of the foregoing possible implementations of the first aspect, in a seventh possible implementation of the second aspect, the receiving unit is further configured to receive a system message sent by the base station before receiving the first TA sent by the base station, where the system message includes a root sequence index and/or format configuration information of a random access preamble; the determining unit is further configured to determine the random access preamble according to the root sequence index number and/or format configuration information of the random access preamble; the transmitting unit is further configured to transmit the random access preamble to the base station.

In a third aspect, a computer-readable storage medium having instructions stored therein is disclosed; when it is run on a terminal as described in the second aspect and any one of its possible implementations, it is caused to perform a random access method as described in the first aspect and its various possible implementations.

In a fourth aspect, a wireless communication device is disclosed, wherein instructions are stored in the wireless communication device, and when the wireless communication device is run on a terminal according to the second aspect and any one of its possible implementations, the wireless communication device causes the terminal to perform a random access method according to the first aspect and its various possible implementations. In a specific implementation, the wireless communication device may be a chip.

For a detailed description of the second aspect, the third aspect, the fourth aspect, and various implementations thereof in the present application, reference may be made to the detailed description of the first aspect and various implementations thereof; moreover, for the beneficial effects of the second aspect, the third aspect, the fourth aspect and various implementation manners thereof, reference may be made to beneficial effect analysis in the first aspect and various implementation manners thereof, and details are not described here.

In a fifth aspect, a random access method is disclosed, which includes:

the base station determines a timing advance adjusting parameter, wherein the timing advance adjusting parameter is used for indicating the terminal to update the first timing advance TA to a second TA; the second TA is greater than the first TA; and the base station sends the timing advance adjusting parameter to the terminal.

In the random access method provided by the embodiment of the invention, the base station can instruct the terminal to adjust the TA through the timing advance adjusting parameter, so that after the terminal sends the uplink data, if a receiving failure response sent by the base station is received, the terminal can adjust the TA according to the timing advance adjusting parameter instructed by the base station to increase the TA, and the second uplink data sent according to the larger TA can reach the base station in the CP.

With reference to the fifth aspect, in a first possible implementation manner of the fifth aspect, the determining, by the base station, a timing advance adjustment parameter specifically includes: and determining a timing advance adjusting coefficient K according to the difference Q between the upper limit of the number of the symbols occupied by the random access lead code supported under the communication system of the terminal and the base station and the number of the symbols occupied by the lead code currently configured by the base station, wherein K is an integer which is more than or equal to 1 and less than or equal to Q.

With reference to the fifth aspect or the first possible implementation manner of the fifth aspect, in a second possible implementation manner of the fifth aspect, the sending, by the base station, the timing advance adjustment parameter to the terminal specifically includes: and sending the timing advance adjusting coefficient K to the terminal so that the terminal updates the first TA to the second TA according to the timing advance adjusting coefficient K.

With reference to the fifth aspect or any one of the foregoing possible implementation manners of the fifth aspect, in a third possible implementation manner of the fifth aspect, the determining, by the base station, the timing advance adjustment parameter specifically includes: receiving a random access lead code sent by a terminal, and calculating a first TA according to the random access lead code; sending the first TA to the terminal; and determining that the uplink data sent by the terminal according to the first TA is not successfully received, and determining a second TA according to a difference Q between the upper limit of the number of the symbols occupied by the random access lead code supported under the communication system in which the terminal and the base station work and the number of the symbols occupied by the lead code currently configured by the base station, wherein the second TA is the first TA + N t, t is the time length of one symbol under the communication system in which the base station and the terminal work, and N is an integer greater than or equal to 0 and less than or equal to Q.

With reference to the fifth aspect or any one of the foregoing possible implementation manners of the fifth aspect, in a fourth possible implementation manner of the fifth aspect, the sending, by the base station, the timing advance adjustment parameter to the terminal specifically includes: and sending the second TA to the terminal.

In a sixth aspect, a base station is disclosed, comprising: a determining unit, configured to determine a timing advance adjustment parameter, where the timing advance adjustment parameter is used to instruct a terminal to update a first timing advance TA to a second timing advance TA; the second TA is greater than the first TA. And the sending unit is used for sending the timing advance adjusting parameter to the terminal.

With reference to the sixth aspect, in a first possible implementation manner of the sixth aspect, the determining unit is specifically configured to determine the timing advance adjustment coefficient K according to a difference Q between an upper limit of the number of symbols occupied by the random access preamble supported by the communication system in which the terminal and the base station operate and the number of symbols occupied by the preamble currently configured by the base station, where K is an integer greater than or equal to 1 and less than or equal to Q.

With reference to the sixth aspect or the first possible implementation manner of the sixth aspect, in a second possible implementation manner of the sixth aspect, the sending unit is specifically configured to send the timing advance adjustment coefficient K to the terminal, so that the terminal updates the first TA to the second TA according to the timing advance adjustment coefficient K.

With reference to the sixth aspect or any one of the possible implementation manners of the sixth aspect, in a third possible implementation manner of the sixth aspect, the base station further includes a receiving unit. The receiving unit is used for receiving a random access lead code sent by the terminal; the determining unit is used for calculating a first TA according to the random access lead code; the sending unit is specifically configured to send the first TA to the terminal; the determining unit is configured to determine that uplink data sent by the terminal according to the first TA is unsuccessfully received, and then determine a second TA according to a difference Q between an upper limit of a number of symbols occupied by a random access preamble supported under a communication system in which the terminal and the base station operate and a number of symbols occupied by a preamble currently configured by the base station, where the second TA is the first TA + N × t, t is a time length of one symbol in the communication system in which the base station and the terminal operate, and N is an integer greater than or equal to 0 and less than or equal to Q.

With reference to the sixth aspect or any one of the possible implementation manners of the sixth aspect, in a fourth possible implementation manner of the sixth aspect, the sending unit is specifically configured to send the second TA to the terminal.

In a seventh aspect, a computer-readable storage medium having instructions stored therein is disclosed; when it is run on the base station according to the above sixth aspect and any one of its possible implementations, it is caused to perform the random access method according to the above fifth aspect and its various possible implementations.

In an eighth aspect, a wireless communication device is disclosed, wherein instructions are stored in the wireless communication device, which when run on a base station according to the above sixth aspect and any one of its possible implementations, cause the base station to perform a random access method according to the above fifth aspect and its various possible implementations. In a specific implementation, the wireless communication device may be a chip.

For a detailed description of the sixth aspect, the seventh aspect, the eighth aspect and various implementations thereof in the present application, reference may be made to the detailed description of the fifth aspect and various implementations thereof; moreover, for the beneficial effects of the sixth aspect, the seventh aspect, the eighth aspect and various implementation manners thereof, reference may be made to beneficial effect analysis in the fifth aspect and various implementation manners thereof, and details are not repeated here.

Drawings

Fig. 1 is a schematic diagram of a terminal uplink collision;

fig. 2 is a frame structure diagram of a random access preamble;

fig. 3 is a flow chart of a conventional random access method;

fig. 4 is a schematic structural diagram of a terminal according to an embodiment of the present invention;

fig. 5 is a flowchart illustrating a random access method according to an embodiment of the present invention;

fig. 6 is another flowchart of a random access method according to an embodiment of the present invention;

fig. 7 is another flowchart of a random access method according to an embodiment of the present invention;

fig. 8 is another flowchart of a random access method according to an embodiment of the present invention;

fig. 9 is another schematic structural diagram of a terminal according to an embodiment of the present invention;

fig. 10 is a schematic structural diagram of a terminal according to an embodiment of the present invention;

fig. 11 is a schematic structural diagram of a base station according to an embodiment of the present invention;

fig. 12 is a schematic structural diagram of a base station according to an embodiment of the present invention;

fig. 13 is another schematic structural diagram of a base station according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described in detail below with reference to the accompanying drawings in the embodiments of the present invention.

As shown in fig. 1, when a plurality of terminals all have a requirement for transmitting data to a base station, collision may occur between different terminals. Therefore, the random access technology is provided, and the time for sending uplink data by different terminals is controlled, so that the collision among the terminals is avoided.

Specifically, the base station broadcasts a system message, where the system message includes time-frequency information of the uplink PRACH, a root sequence index, a cyclic shift (cyclic shift), and the like. And the terminal detects the synchronous sequence to complete downlink synchronization. Further, the terminal may also send a Random Access Preamble on RACH in uplink to the base station according to the system message broadcast by the base station, so as to initiate Random Access.

As shown in fig. 2, a random access Preamble (hereinafter, Preamble) includes a Cyclic Prefix (CP), a Preamble sequence, and a guard time GT.

Among them, a Cyclic Prefix (CP) is used to cope with multipath, ensuring orthogonality between multiple access users. The guard time GT is used as a guard interval to avoid interference to the signal of the next subframe. The preamble sequence is used for the base station to detect the random access request of the terminal and for measuring the uplink timing advance.

The Preamble in the LTE has four configurations, namely configurations 0-3, and specifically, table 1 shows specific situations of the four configurations:

TABLE 1

Note that T in Table 1_SIs the time domain sampling interval, about 32.55 ns.

As shown in fig. 3, the random access procedure of the terminal mainly includes the following four steps:

firstly, a terminal sends Msg1 to a base station through a PRACH, and the Msg1 comprises a random access preamble.

Specifically, the terminal may determine a random access Preamble according to a root sequence number in a system message broadcast by the base station, and send the Preamble on a time-frequency resource corresponding to PRACH time-frequency information in the system message.

And secondly, the base station sends Msg2 to the terminal, and the Msg2 comprises TA calculated by the base station for the terminal.

Here, the Msg2 may be a Random Access Response (RAR) message.

And thirdly, the terminal determines the uplink timing according to the TA and sends the Msg3 to the base station.

The Msg3 may be a first scheduled UL transmission UL-SCH, that is, data that the terminal first transmits through an uplink shared channel.

The terminal can determine the time for sending the Msg3 according to the TA in the Msg2, that is, the uplink synchronization is completed, and then the terminal can transmit the Msg3 in the uplink resource allocated to the terminal by the base station, wherein the Msg3 can be the uplink data of the initial transmission, and the terminal requests to access the base station for subsequent data transmission by sending the Msg3 to the base station.

It should be noted that an important feature of uplink transmission is that different UEs have orthogonal multiple access (orthogonal multiple access) in time and frequency, i.e. uplink transmissions from different UEs in the same cell do not interfere with each other. In order to ensure orthogonality of uplink transmission and avoid interference in a cell, a base station requires that signals transmitted by different terminals through the same subframe but different frequency domain resources arrive at the base station with substantially aligned time. Specifically, as long as the base station receives the uplink data sent by the UE within the cp (cyclic prefix) range of the currently configured Preamble, the uplink data can be correctly decoded. If the Msg3 sent by the terminal does not arrive at the base station within the CP, it is considered as interference by the base station, and the base station cannot successfully demodulate and decode the received Msg3, i.e., if the Msg3 sent by the terminal does not arrive at the base station within the CP, the Msg3 cannot be successfully received by the base station. The base station enables the time of the uplink signals from different terminals to reach the base station to be basically aligned by indicating the TA of each terminal, and the terminal far away from the base station has larger transmission time delay, and the needed TA is larger than the TA of the terminal near the center of the base station.

In addition, Msg3 supports HARQ processes, i.e., the base station may send a NACK (reception failure response) to the terminal when it did not successfully receive Msg3, indicating that the terminal retransmitted Msg 3. The base station tells the terminal to retransmit the resource and the position of the Msg3 through DCI0 scrambled by Temporary C-RNTI.

And fourthly, the base station sends the Msg4 to the terminal to indicate the competition result of the random access of the terminal.

The Msg4 may be a Contention Resolution on DL message, the base station and the terminal may finally complete Contention Resolution through Msg4, and for the case of initial access and re-establishment, the MAC PDU in Msg4 may carry a Contention Resolution flag.

In addition, the Msg4 also supports HARQ processes, and only terminals that complete contention resolution will feed back ACKs to the base station. After the terminal receives the Msg4, if it is determined that the terminal completes contention resolution according to the contention resolution flag in the Msg4, that is, the contention successfully accesses the base station, the terminal may indicate ACK to the base station through PUCCH, and a physical layer (PHY) of the base station receives the ACK and reports the ACK to a Media Access Control (MAC) layer of the base station.

Generally, after receiving a preamble sent by a UE, a base station calculates a TA for a terminal, and the terminal determines an uplink sending time according to the TA to send the Msg3, where if the TA calculated by the base station for the terminal is inaccurate, the uplink sending time determined by the terminal is inaccurate, and further the base station cannot successfully receive the Msg3 sent by the terminal.

In a specific implementation, the base station estimates the TA in units of 1 PRACH symbol duration. That is, if the transmission delay of the preamble transmitted by the terminal to the base station exceeds the symbol duration T in the communication system, the TA determined by the base station is inaccurate. And the TA calculated by the base station for the terminal is N less symbol duration T. Where N is an integer of 1 or more.

Generally, a transmission delay (RTD) per 1km when a terminal transmits data to a base station is 6.7 μ s, so that the base station can estimate a TA of the terminal at maximum distance from the base station (T/6.7) km. The coverage area of the serving cell of the base station is a range with a radius of (T/6.7) km around the base station. That is, in the terminals out of the cell coverage, the time it takes for the base station to transmit the preamble is longer than 1 symbol duration, so the base station cannot accurately calculate the TA of these terminals.

In LTE, Msg1 (including preamble) is sent in PRACH, and the PRACH subcarrier spacing in LTE is 1.25kHz, and the typical 1-symbol duration in time domain is the inverse of the subcarrier spacing, i.e. one symbol duration in LTE is about 800 μ s (i.e. 1/1.25 s). That is, in LTE, the base station can accurately estimate the TA of the terminal within 120km of the cell coverage radius.

Compared with LTE, the PRACH subcarrier spacing in the NR system supports the 30/60/120kHz scenario, i.e., the PRACH supports a large subcarrier spacing. Taking the PRACH subcarrier spacing of 120kHz as an example, the duration of each symbol of the PRACH is approximately 8.3 μ s (i.e., 1/120 s). By adopting the current TA measuring mechanism, the coverage radius of a cell is about 8.3/6.7 ≈ 1.25km, and a base station can only correctly calculate the TA of a terminal within the range of 1.25km away from the base station.

Therefore, under the subcarrier interval with large high frequency, the occupied time of the RACH preamble is shortened, and the coverage radius of the cell is too small. That is, the base station can only accurately calculate the TA of the terminals within a small range, and for a large number of terminals outside the coverage of the serving cell of the base station, the base station cannot accurately estimate the TA of the terminals. Due to the fact that TA is estimated incorrectly, Msg3 sent by different terminals cannot reach a base station in a Cyclic Prefix (CP), orthogonality among different terminals is affected, intersymbol crosstalk is caused, decoding cannot be achieved, and therefore the terminals cannot be accessed successfully.

The principle of the embodiment of the invention is as follows: a corresponding TA adjustment mechanism is defined, and the terminal can adjust the TA,

specifically, the terminal sends a random access preamble to the base station, and the base station calculates a first TA for the terminal according to the random access preamble sent by the terminal and sends the first TA to the terminal. And the terminal sends first uplink data according to the first TA, the first uplink data is not successfully received by the base station, and the base station sends a receiving failure response to the terminal. And after receiving the receiving failure response, the terminal adjusts the first TA to a second TA which is larger than the first TA, and then the terminal sends second uplink data according to the second TA. Generally, the first uplink data in the base station is not successfully received by the base station, and it is likely that the TA calculated by the base station for the terminal is too small because the terminal is outside the coverage cell of the base station, so the terminal can increase the first TA, and the second uplink data sent according to the larger TA may reach the base station in the CP, and thus, in a high-frequency situation, the embodiment of the present invention can improve the success probability of the random access of the terminal.

The random access method provided by the embodiment of the present application may be applied to a terminal, which may be the terminal in fig. 1. As shown in fig. 4, the terminal may include at least one processor 11, a memory 12, a transceiver 13, and a communication bus 14.

The following describes the various components of the terminal in detail with reference to fig. 4:

the processor 11 is a control center of the terminal, and may be a single processor or a collective term for a plurality of processing elements. For example, the processor 11 is a Central Processing Unit (CPU), and may be an Application Specific Integrated Circuit (ASIC), or one or more Integrated circuits configured to implement embodiments of the present invention, such as: one or more microprocessors (digital signal processors, DSPs), or one or more Field Programmable Gate Arrays (FPGAs).

The processor 11 may perform various functions of the terminal by running or executing software programs stored in the memory 12 and calling data stored in the memory 12, among others.

In particular implementations, processor 11 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG. 4, for example, as one embodiment.

In particular implementations, the terminal may include multiple processors, such as processor 11 and processor 15 shown in FIG. 4, as one embodiment. Each of these processors may be a single-Core Processor (CPU) or a multi-Core Processor (CPU). A processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (e.g., computer program instructions).

The Memory 12 may be a Read-Only Memory (ROM) or other type of static storage device that can store static information and instructions, a Random Access Memory (RAM) or other type of dynamic storage device that can store information and instructions, an Electrically Erasable Programmable Read-Only Memory (EEPROM), a Compact Disc Read-Only Memory (CD-ROM) or other optical Disc storage, optical Disc storage (including Compact Disc, laser Disc, optical Disc, digital versatile Disc, blu-ray Disc, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited to these. The memory 12 may be self-contained and coupled to the processor 11 via a communication bus 14. The memory 12 may also be integrated with the processor 11.

Wherein, the memory 12 is used for storing software programs for executing the invention scheme and is controlled by the processor 11 to execute.

The transceiver 13, which may be any transceiver or the like, is used for communication with other devices in the system of fig. 1, such as a base station or other terminals in fig. 1. And may also be used to communicate with communications Networks, such as ethernet, Radio Access Network (RAN), Wireless Local Area Networks (WLAN), etc. The transceiver 13 may include a receiving unit implementing a receiving function and a transmitting unit implementing a transmitting function.

The communication bus 14 may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended ISA (EISA) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown in FIG. 4, but this does not indicate only one bus or one type of bus.

The arrangement of devices shown in fig. 4 is not intended to be limiting and may include more or fewer components than shown, or some components may be combined, or a different arrangement of components.

An embodiment of the present invention provides a random access method, as shown in fig. 5, the method includes the following steps:

101. the terminal receives a system message of the base station.

In a specific implementation, the base station broadcasts a system message, and the terminal can receive the system message. The system message comprises time frequency information of the uplink PRACH and/or a root sequence index number and/or cyclic shift and the like.

102. The terminal determines a random access preamble.

In a specific implementation, the terminal may determine a random access preamble according to the root sequence index number in the system message received in step 101. In general, the random access preamble may be a ZC sequence of length 839. In the embodiment of the present invention, the random access Preamble may be denoted as Preamble.

103. The terminal transmits a random access preamble to the base station.

In a specific implementation, the terminal sends the random access preamble to the base station through a time-frequency position indicated by the time-frequency information of the system message, which includes the uplink PRACH. The terminal transmits a random access preamble to the base station through the aforementioned Msg 1. In addition, the base station can blindly detect the random access lead code in the PRACH, and if the base station detects the random access lead code, the random access lead code is reported to the MAC layer of the base station.

104. And the base station calculates a first TA for the terminal according to the received random access preamble.

In the specific implementation, the base station estimates the TA in units of one PRACH symbol duration, detects a random access preamble at each symbol, and determines an energy maximum at a certain time of a certain symbol, and then considers that the random access preamble transmission of the terminal is completed. If the time length of the random access preamble of the terminal reaching the base station exceeds one symbol time length, the time that the base station receives the random access preamble of the terminal is inevitably not in the first PRACH symbol, such as: reception is completed within the qth PRACH symbol. The base station refers to the starting time of the Q-th PRACH symbol when calculating the TA for the terminal, so that the TA calculated for the terminal by the base station is smaller when the time length of the random access preamble of the terminal reaching the base station exceeds one symbol time length. Further, the duration of N PRACH symbols is smaller.

105. The terminal receives a first TA sent by the base station.

In step 103, after the terminal sends the random access Preamble, if the base station detects the Preamble. The subsequent base station will feed back a Random Access Response (RAR) of the MAC in a Physical Downlink Shared Channel (PDSCH) within the random Access Response window. Wherein, the RAR can be regarded as the aforementioned Msg2 and is carried in DL-SCH.

In addition, the TA calculated by the base station for the terminal is also carried in the RAR, and the RAR includes: the Preamble sent by the terminal in step 103, the backoff parameter, PUSCH uplink scheduling information allocated for the terminal to transmit the first uplink data (which may be considered as the initial transmission of the Msg 3), and a Temporary cell RNTI (Temporary cell RNTI, Temporary C-RNTI). Wherein, the Preamble is used for the terminal matching operation, and if the terminal determines that the Preamble in the received RAR is the same as the Preamble sent by the terminal in step 103, the information contained in the RAR can be considered to be related to the terminal; the backoff parameter is a time that the terminal re-initiates the Preamble code to be delayed, that is, once the terminal receives a reception failure response sent by the base station, indicating that the random access code sent by the terminal is not successfully received by the base station, the terminal should postpone a certain time (the time length indicated by the backoff parameter) and then send the random access Preamble code again; the RNTI is used for scrambling first uplink data to be sent by the terminal; the PUSCH uplink scheduling information allocated for the terminal to transmit the first uplink data comprises the following steps: whether to frequency hop, modulation code rate, access resource, access time, etc.

In a specific implementation, the terminal obtains the TA by decoding the RAR sent by the base station. Further, the terminal obtains the RAR transmitted by the base station by decoding the PDSCH channel. When decoding the PDSCH Channel, the terminal first decodes the Physical Downlink Control Channel (PDCCH) resource allocation information by accessing a random access radio network temporary identity (RA-RNTI), and then continues to decode the PDSCH Channel content. And the terminal can determine the RA-RNTI according to the PRACH time-frequency resource location carrying the Msg1, where Msg1 is a message used by the terminal to send the random access preamble in step 103.

In addition, both the terminal and the base station can calculate the RA-RNTI value, so the base station does not need to transmit the RA-RNTI to the terminal in an air interface.

106. And the terminal sends first uplink data to the base station according to the first TA.

In a specific implementation, the terminal determines a first uplink transmission time according to the first TA, and transmits first uplink data at the first uplink transmission time. The first uplink transmission time determined by the terminal may be: t1+ scheduling delay (3 ms — 2 × TA in LTE FDD), where T1 is the time when the terminal receives Msg2 in step 105, and TA is the first TA.

In addition, the terminal sends the first uplink data to the base station by carrying the first uplink data in the Msg3, and the first uplink data can be considered as the initial transmission of the Msg 3. The initial transmission of the Msg3 is only one uplink transmission dynamically scheduled through the Msg2 message of the MAC layer, and other uplink transmissions in the random access process are dynamically scheduled through the DCI 0.

In addition to the first uplink data, the Msg3 may also carry Radio Resource Control (RRC) link setup messages, RRC reestablishment messages, and so on. If the Msg3 contains the layer 3 message, the base station needs to store the CCCH SDU information corresponding to the layer 3 message in the Msg3, and the CCCH SDU information can be sent back to the terminal as a competition resolving identifier, so that the terminal can recognize the CCCH SDU information to confirm that the terminal completes the competition and successfully accesses the base station.

107. And the terminal receives a receiving failure response sent by the base station, wherein the receiving failure response is used for indicating that the base station does not successfully receive the first uplink data.

It should be noted that the Msg3 message carrying the first uplink data supports the HARQ process, and when the base station does not successfully receive the Msg3 sent by the terminal, the base station replies to the terminal with a reception failure response indicating that the Msg3 is not successfully received by the base station. It can be understood that, if the base station does not successfully receive the first uplink data, the terminal may reply a reception failure response to the terminal. In the embodiment of the present invention, the reception failure response may be NACK.

108. And the terminal updates the first TA to a second TA, wherein the second TA is larger than the first TA.

Once the terminal receives the reception failure response sent by the base station in step 107, it indicates that the first uplink data sent by the terminal is not successfully received by the base station. It may be that the terminal is far from the base station, and the time length for the random access preamble of the terminal to reach the base station exceeds one symbol time length, so the TA calculated by the base station for the terminal is small, and further, is small by N PRACH symbol time lengths.

In a specific implementation, the terminal may increase the first TA by using one symbol duration as the adjustment step size. For example, the first TA + N symbol duration is the second TA.

In addition, the terminal may update the first TA to the second TA according to the timing advance adjustment parameter issued by the base station. The timing advance adjustment parameter may be a TA (i.e., the second TA) determined by the base station, and after the timing advance adjustment parameter is issued to the terminal, the terminal may directly update the current TA to the TA issued by the base station. In a specific implementation, the second TA is the first TA + N × t, where t is a time length of one symbol in a communication system in which the base station and the terminal operate, for example: the time length of one symbol is 800us in LTE. N is an integer which is more than or equal to 0 and less than or equal to Q, and Q is the difference value between the upper limit of the number of the symbols occupied by the random access lead code supported under the communication system in which the terminal and the base station work and the number of the symbols occupied by the lead code currently configured by the base station.

The timing advance adjustment parameter may be a timing advance adjustment coefficient K (K is an integer of 1 or more and Q or less) for updating the first TA to N₀+ t × K. Wherein N is₀Is the first TA.

In the random access method provided by the embodiment of the invention, after the terminal sends the uplink data, if a reception failure response sent by the base station is received, the terminal can adjust the TA, so that the TA can be increased, and the second uplink data sent according to the larger TA can possibly reach the base station in the CP.

In some embodiments, the base station may send a timing advance adjustment coefficient K to the terminal, and instruct the terminal to adjust the TA according to K. Based on this, an embodiment of the present invention provides a random access method, as shown in fig. 6, where the method includes the following steps:

201. and the base station sends a cell-level system message to the terminal, wherein the system message comprises configuration information of a Preamble, a root sequence index number and a timing advance adjusting coefficient K.

For example, the Preamble configuration information may be the Preamble format in table 1, such as: 0 to 3. K is an integer of 1 to Q. And Q is the difference value between the upper limit of the number of the symbols occupied by the random access lead code supported by the communication system in which the terminal and the base station work and the number of the symbols occupied by the lead code currently configured by the base station. For example, the communication system where the terminal and the base station operate is NR, where a random access preamble code under NR may occupy at most 12 symbols, if the number of symbols occupied by the preamble code currently configured by the base station is 3, Q is 9, and K is an integer greater than or equal to 1 and less than or equal to 9, for example: 3.

specifically, the base station supports that the random access preamble occupies S symbols at most, that is, the base station can accurately calculate the TA of the terminal within kilometer of the base station (S × t/6.7), where t is a symbol duration. Assume that the length of the random access preamble currently configured by the base station is P symbols, that is, the base station can currently accurately calculate the TA of the terminal within kilometer of the base station (P × t/6.7). If the terminal is according to the TA (namely the initial TA measured value N of the embodiment of the invention) issued by the base station for the first time₀) The time of the transmitted uplink data arriving at the base station is not within the cyclic prefix, the uplink data is not successfully received by the base station, and the terminal can be considered to be out of the kilometer range from the base station (P x t/6.7), but if the terminal is within the kilometer range from the base station (S x t/6.7), the base station can calculate the accurate TA for the terminal, and only needs to be within N₀Is increased with symbol duration, and N₀At most, only (S-P ═ Q) symbols can be added.

202. And the terminal sends a Preamble to the base station.

The terminal may determine a Preamble according to the root sequence index received in step 201.

203. The base station feeds back RAR to the terminal, and the RAR comprises an initial TA measurement value N₀。

The initial TA measurement value is the first TA according to the embodiment of the present invention.

204. The terminal measures the value N according to the initial TA₀And transmitting the first uplink data.

In a specific implementation, as shown in fig. 6, the terminal first performs N₀Determining an upstream transmission time T₁At T₁RV0 (redundancy version 0) is sent to the base station and a NACK is received from the base station. The terminal is according to N₀Determining an upstream transmission time T₂At T₂Transmitting RV2 to base station(redundancy version 2), NACK by the base station reply is received. The terminal is according to N₀Determining an upstream transmission time T₃At T₃RV3 (redundancy version 3) is sent to the base station, and a NACK is received from the base station. The terminal is according to N₀Determining an upstream transmission time T₄At T₄RV1 (redundancy version 1) is sent to the base station, and NACK sent by the base station is received.

Wherein, T₁The time when the terminal receives the RAR in step 203 + scheduling delay-2 × N₀；T₂According to T₁Time of NACK reception + scheduling delay-2 × N after transmission of RV0₀；T₃According to T₂Time of NACK reception + scheduling delay-2 × N after transmission of RV2₀；T₄According to T₃Time of NACK reception + scheduling delay-2 × N after transmission of RV3₀。

Here, RV0 to RV4 may be referred to as first uplink data.

205. The terminal sends TA to N₀Is updated to N₀+t*K。

The adjusted TA is called N ═ N₀And t is a symbol duration of a communication system in which the base station and the terminal work.

Illustratively, t is 2048Ts 2048 × 32.55ns ≈ 66.7us, which is the symbol duration at a NR subcarrier spacing of 15kHz, 2048Ts ≈ 8.3us, which is the symbol duration at a NR subcarrier spacing of 120 kHz.

206. Terminal according to N₀And + t × K transmits second uplink data.

In a specific implementation, as shown in fig. 6, the terminal first determines an uplink transmission time T according to N₁', at T₁'RV' 0 (redundancy version 0) is sent to the base station, and NACK replied by the base station is received. The terminal determines an uplink transmission time T according to N₂', at T₂'transmitting RV' 2 (redundancy version 2) to the base station, receiving NACK from the base station. The terminal determines an uplink transmission time T according to N₃', at T₃'transmitting RV' 3 (redundancy version 3) to base station, receiving base stationA NACK of the reply. The terminal determines an uplink transmission time T according to N₄', at T₄'transmitting RV' 1 (redundancy version 1) to the base station, and receiving NACK transmitted by the base station.

Here, RV '0 to RV' 4 may be referred to as second uplink data.

Table 2 shows details of uplink data transmission from the terminal to the base station in step 204 and step 205, which are as follows:

TABLE 2

In table 2, the 1 st to 4 th transmissions are four uplink transmissions in step 204, and the 1 st to 4 th transmissions are four uplink transmissions in step 205.

207. The terminal successfully receives the competition resolving message, which indicates that the terminal is successfully accessed randomly.

For the description of the "contention resolution message", see the related explanation in step 110, and are not described herein.

In the random access method provided by the embodiment of the invention, the base station indicates the timing advance adjustment coefficient K to the terminal through the cell-level system message, so that the terminal can complete TA adjustment at one time according to the K, the influence of TA adjustment of the terminal on uplink transmission of other terminals in a cell is avoided to a certain extent, and meanwhile, the success rate of terminal access can be increased.

In some embodiments, the terminal may adjust the TA by itself with one symbol duration as an adjustment step size, and based on this, an embodiment of the present invention provides a random access method, as shown in fig. 7, where the method includes the following steps:

301. the base station sends a cell-level system message to the terminal, wherein the system message comprises configuration information of a Preamble (random access Preamble) and a root sequence index number.

For example, the Preamble configuration information may be the Preamble format in table 1, such as: 0 to 3.

302. And the terminal sends a Preamble to the base station.

303. The base station feeds back RAR to the terminal, and the RAR comprises an initial TA measurement value N₀。

304. The terminal measures the value N according to the initial TA₀And transmitting the first uplink data.

In a specific implementation, as shown in fig. 7, the terminal first performs N₀Determining an upstream transmission time T₁At T₁RV0 (redundancy version 0) is sent to the base station and a NACK is received from the base station. The terminal is according to N₀Determining an upstream transmission time T₂At T₂RV2 (redundancy version 2) is sent to the base station, and a NACK is received from the base station. The terminal is according to N₀Determining an upstream transmission time T₃At T₃RV3 (redundancy version 3) is sent to the base station, and a NACK is received from the base station. The terminal is according to N₀Determining an upstream transmission time T₄At T₄RV1 (redundancy version 1) is sent to the base station, and NACK sent by the base station is received.

Here, RV0 to RV4 may be referred to as first uplink data.

305. The terminal sends TA to N₀Is updated to N₀And + t × i, transmitting the second uplink data according to the updated TA.

Wherein i belongs to [1, Q ], Q is an integer, Q is a difference value between the upper limit of the number of symbols occupied by the random access lead code supported by the base station and the number of symbols occupied by the lead code currently configured by the base station, and t is the time length of one symbol in the communication system in which the base station and the terminal work.

In a specific implementation, according to N₀+t×i、i∈[1,Q]Q uplink timing advances may be determined. In the embodiment of the present invention, N determined when i ═ 1 can be considered₀+ tx1 is the first uplink timing advance, N, of the Q uplink timing advances₀And + t × i is the ith uplink timing advance in the Q uplink timing advances.

As shown in fig. 7, the terminal first takes i ═ 1, according to N₀+ t × 1 transmits uplink data, and if NACK transmitted by the base station is received, i is taken to be 2, and N is used as the basis₀+ tx 2 transmits uplink data. And so on, that is, the base station uses t as the step size for adjusting the TA, sends uplink data according to the adjusted TA, and continues to adjust the TA using t as the step size once receiving NACK replied by the base station.

Aiming at the ith uplink timing advance 'N' in the Q uplink timing advances₀And determining an uplink transmission time and transmitting uplink data according to the + t × i', and if the terminal receives a reception failure response transmitted by the base station, determining an uplink transmission time according to the N + t × i +1 and transmitting the uplink data at the uplink transmission time.

It should be noted that in NR, since the subcarrier interval becomes larger to reduce the cell coverage radius, in order to increase the coverage radius of the cell at the high-frequency subcarrier interval, NR supports increasing the cell coverage radius by means of Preamble sequence repetition, the length of the Preamble in NR that may be configured may be 1, 2, 4, 6, or 12 symbol durations, and the symbol duration is the time length of one symbol in the communication system in which the base station and the terminal operate. That is, the above-mentioned "upper limit of the number of symbols occupied by the random access preamble code supported by the base station" in NR is 12. If the configuration information of the Preamble received in step 301 indicates that the length of the Preamble configuration is Y, Q is 12-Y. For example, the Preamble currently configured length is 6 symbol durations, and then Q-12-6.

Specifically, the base station supports that the random access preamble occupies S symbols at most, that is, the base station can accurately calculate the TA of the terminal within kilometer of the base station (S × t/6.7), where t is a symbol duration. Assume that the length of the random access preamble currently configured by the base station is P symbols, that is, the base station can currently accurately calculate the TA of the terminal within kilometer of the base station (P × t/6.7). If the terminal is according to the TA (namely the initial TA measured value N of the embodiment of the invention) issued by the base station for the first time₀) The time of the transmitted uplink data reaching the base station is not within the cyclic prefix, the uplink data is not successfully received by the base station, and the terminal can be considered to be inOut of kilometer range from the base station (P x t/6.7), but if the terminal is within kilometer range from the base station (S x t/6.7), the base station can calculate the exact TA for the terminal, only at N₀Is increased with symbol duration, and N₀At most, only (S-P ═ Q) symbols can be added.

Table 3 shows specific conditions of several configurations of preambles at an interval of 20KHz for 1 subcarrier in NR, which are as follows:

TABLE 3

It should be noted that "0-1" in table 3 is only a possible implementation manner of the Preamble configuration number in NR, and the Preamble configuration number may be in other forms, which is not limited in this embodiment of the present invention. In addition, when the PRACH subcarrier interval is configured otherwise, the Preamble may have other configurations, which is not limited in the embodiment of the present invention.

The terminal firstly according to N₀+ tx1 determines an uplink transmission time and transmits uplink data at the time, and if receiving the reception failure response transmitted by the base station, the terminal transmits the uplink data according to N₀+ tx2 determines an uplink transmission time, and transmits uplink data at the time, and so on, and directly receives the contention resolution message transmitted by the base station.

In a specific implementation, four redundancy versions are sent when the terminal determines that uplink data is sent after one TA, which is exemplified by: according to N₁(equal to N)₀+ tx 1) sending four redundancy versions of uplink data, if the terminal receives the receiving failure response sent by the base station, then according to N₂(equal to N)₀+ t × 2) sending four redundancy versions of uplink data, and receiving a reception failure response … … sent by the base station according to N_i(equal to N)₀+ t × i) transmits the uplink data of four redundancy versions.

It should be noted that the terminal is not necessarily based on N₁～N_iThe redundancy version is transmitted, as long as the uplink data transmitted according to a certain value thereof is successfully received by the base station,the terminal receives the contention resolution message transmitted from the base station, and the terminal may not transmit uplink data according to a value after the value. Illustratively, the terminal is according to N₃The transmitted uplink data is successfully received by the base station, the terminal receives the competition resolving message transmitted by the base station, and the terminal does not need to be according to N₄～N_iAnd then transmits the uplink data.

Table 4 gives details of the uplink data transmission from the terminal to the base station in step 305, which are as follows:

TABLE 4

306. And the terminal receives the competition resolving message sent by the base station and indicates that the terminal is successfully accessed randomly.

In the random access method provided by the embodiment of the invention, the terminal automatically completes the adjustment of the TA, and the base station does not need to indicate how the terminal adjusts the TA through the downlink message, so that the signaling overhead in the aspect of indication of the base station can be reduced, and the access success rate of the terminal can be increased.

In some embodiments, the base station may directly indicate the increment of the TA to the terminal, and based on this, an embodiment of the present invention provides a random access method, as shown in fig. 8, where the method includes the following steps:

401. and the base station sends a cell-level system message to the terminal, wherein the system message comprises configuration information of a Preamble and a root sequence index number.

402. And the terminal sends a Preamble to the base station.

403. The base station feeds back RAR to the terminal, and the RAR comprises an initial TA measurement value N₀。

404. The terminal measures the value N according to the initial TA₀And transmitting the first uplink data.

405. If the base station determines that the first uplink data sent by the terminal is not successfully received, the base station calculates the uplink timing advance N of the terminal₁。

In a specific implementation, the terminal is far away from the base station, and a time required for the base station to completely receive the Preamble sent by the terminal exceeds one symbol duration, so the TA sent by the base station in step 403 is smaller, and specifically, may be smaller by N symbol durations. Therefore, if the time of the uplink data sent by the terminal reaching the base station is within the CP included in the Preamble currently configured by the base station, the TA, that is, N, sent by the base station in step 403 can be sent by the base station₀Increasing the duration of N symbols, i.e. N₁＝N₀+ N × t. Where t is a time length of a symbol in a communication system in which the base station and the terminal operate, for example: the time length of one symbol is 800us in LTE. N is an integer which is more than or equal to 0 and less than or equal to Q, and Q is the difference value between the upper limit of the number of the symbols occupied by the random access lead code supported under the communication system in which the terminal and the base station work and the number of the symbols occupied by the lead code currently configured by the base station. For example, the communication system where the terminal and the base station operate is NR, where a random access preamble code under NR may occupy at most 12 symbols, if the number of symbols occupied by the preamble code currently configured by the base station is 3, Q is 9, and further N is an integer greater than or equal to 1 and less than or equal to 9, for example: 3.

406. the base station retransmits RAR to the terminal, and the retransmitted RAR contains the fixed N₁。

407. The terminal receives RAR sent by the base station and according to N₁And sending the second uplink data.

Wherein N is₁Namely, the second TA according to the embodiment of the present invention.

408. And the terminal receives the competition resolving message sent by the base station and indicates that the terminal is successfully accessed randomly.

The base station provided by the embodiment of the invention indicates the second TA in a level mode through the RAR terminal, so that the access time delay can be reduced while the coverage area is increased and the access success rate is improved, and meanwhile, the influence on uplink transmission of other terminals in a cell is reduced.

In some embodiments, the base station can also increment the timing advance by N ^ according to which the terminal is₀+ N ^ determines the second TA and according to N₀And + N ^ sending uplink data.

In some embodiments, if the TA determined by the base station for the terminal is too large, the terminal may also adjust the first TA to a smaller value, where it is not limited that the second TA is necessarily larger than the first TA, and the terminal may increase or decrease the first TA according to the actual indication.

Fig. 9 shows a possible structure diagram of the terminal involved in the above embodiment in the case of dividing each functional module by corresponding functions. As shown in fig. 9, the terminal includes a receiving unit 501, a transmitting unit 502, and an updating unit 503.

A receiving unit 501, configured to support the terminal to perform step 101, step 105, step 107, step 110, step 201, step 203, step 204, step 206, step 207, step 301, step 303, step 304, step 305, step 306, step 401, step 403, step 404, step 406, step 408, and/or other processes for the techniques described herein in the foregoing embodiments;

a sending unit 502, configured to support the terminal to perform step 103, step 106, step 109, step 202, step 204, step 206, step 302, step 304, step 305, step 402, step 404, step 407, and/or other processes for the techniques described herein in the foregoing embodiments;

an updating unit 502, configured to support the terminal to perform the steps of updating the timing advance in step 108, step 205, step 305, and step 406 in the foregoing embodiments, and/or other processes for the technology described herein;

it should be noted that all relevant contents of each step related to the above method embodiment may be referred to the functional description of the corresponding functional module, and are not described herein again.

Illustratively, in the case of using an integrated unit, a schematic structural diagram of a terminal provided in the embodiment of the present application is shown in fig. 10. In fig. 10, the terminal includes: a processing module 601 and a communication module 602. The processing module 601 is used for controlling and managing the actions of the terminal, for example, performing the steps performed by the updating unit 503, and/or other processes for performing the techniques described herein. The communication module 602 is configured to support interaction between the terminal and other devices, for example, perform the steps performed by the receiving unit 501 and the sending unit 502. As shown in fig. 10, the terminal may further include a storage module 603, and the storage module 603 is used for storing program codes and data of the terminal.

When the processing module 601 is a processor, the communication module 602 is a transceiver, and the storage module 603 is a memory, the terminal is the terminal shown in fig. 4. When the processing module 601 is a processor and the communication module 602 is a transceiver, the terminal is the terminal shown in fig. 4. If the transceiver is a receiver and a transmitter, the receiver performs the steps performed by the receiving unit 501 and the transmitter performs the steps performed by the transmitting unit 502.

Fig. 11 shows a schematic diagram of a possible structure of the base station involved in the above embodiment, in the case of dividing each functional module according to each function. As shown in fig. 11, the base station includes a receiving unit 701, a transmitting unit 702, and a determining unit 703.

A receiving unit 701, configured to support the base station to perform step 103, step 106, step 109, step 202, step 204, step 206, step 302, step 304, step 305, step 402, step 404, step 407, and/or other processes for the techniques described herein in the foregoing embodiments;

a sending unit 702, configured to support the base station to perform step 101, step 105, step 107, step 110, step 201, step 203, step 204, step 206, step 207, step 301, step 303, step 304, step 305, step 306, step 401, step 403, step 404, step 406, step 408, and/or other processes for the techniques described herein in the foregoing embodiments;

a determining unit 703 for supporting the base station to perform step 104, step 405 in the above embodiments, and/or other processes for the techniques described herein;

For example, in the case of using an integrated unit, a schematic structural diagram of a base station provided in the embodiment of the present application is shown in fig. 12. In fig. 12, the base station includes: a processing module 801 and a communication module 802. The processing module 801 is configured to control and manage actions of the base station, for example, perform the steps performed by the determination unit 703 and/or perform other processes for performing the techniques described herein. The communication module 802 is configured to support interaction between a base station and other devices, for example, perform the steps performed by the receiving unit 701 and the sending unit 702. As shown in fig. 11, the base station may further include a storage module 803, and the storage module 803 is used for storing program codes and data of the base station.

When the processing module 801 is a processor, the communication module 802 is a transceiver, and the storage module 803 is a memory, the base station is the base station shown in fig. 13.

If the transceiver is a receiver and a transmitter, the receiver performs the steps performed by the receiving unit 701 and the transmitter performs the steps performed by the transmitting unit 702.

In the above embodiments, all or part of the implementation may be realized by software, hardware, firmware or any combination thereof. When implemented using a software program, may take the form of a computer program product, either entirely or partially. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the application to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

Through the above description of the embodiments, it is clear to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional modules is merely used as an example, and in practical applications, the above function distribution may be completed by different functional modules according to needs, that is, the internal structure of the device may be divided into different functional modules to complete all or part of the above described functions.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described device embodiments are merely illustrative, and for example, the division of the modules or units is only one logical functional division, and there may be other divisions when actually implemented, for example, a plurality of units or components may be combined or may be integrated into another device, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may be one physical unit or a plurality of physical units, that is, may be located in one place, or may be distributed in a plurality of different places. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially or partially contributed to by the prior art, or all or part of the technical solutions may be embodied in the form of a software product, where the software product is stored in a storage medium and includes several instructions to enable a device (which may be a single chip, a chip, or the like) or a processor (processor) to execute all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only an embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present disclosure should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A random access method, comprising:

a terminal receives a first uplink Timing Advance (TA) sent by a base station and sends first uplink data to the base station according to the first TA;

the terminal receives a receiving failure response sent by the base station, and updates the first TA to a second TA, wherein the second TA is larger than the first TA; the reception failure response is used for indicating that the base station does not successfully receive the first uplink data;

the terminal sends second uplink data to the base station according to the second TA;

and the terminal receives a timing advance adjusting coefficient K sent by the base station, wherein the K is an integer which is more than or equal to 1 and less than or equal to Q, and the Q is a difference value between the upper limit of the number of the symbols occupied by the random access lead code supported under the communication system in which the terminal and the base station work and the number of the symbols occupied by the lead code currently configured by the base station.

2. The method according to claim 1, wherein the updating the first TA to the second TA specifically comprises:

determining the second TA as N₀+ t × K, where N₀For the first TA, t is a time length of one symbol in a communication system in which the base station and the terminal operate.

3. The method according to claim 1, wherein the updating the first TA to the second TA specifically comprises:

and receiving the second TA sent by the base station, and updating the first TA into the received second TA.

4. The method of claim 2, wherein the sending, by the terminal to the base station, the second uplink data according to the second TA specifically comprises:

and determining a first uplink transmission time according to the second TA, and transmitting the second uplink data at the first uplink transmission time.

5. The method according to claim 1, wherein the updating the first TA to the second TA specifically comprises:

according to N₀+ t × Q determines Q uplink timing advances, where the second TA includes the Q uplink timing advances, where Q e [1, Q]Q is an integer, and Q is a difference value between an upper limit of the number of symbols occupied by the random access preamble code supported by the communication system in which the terminal and the base station work and the number of symbols occupied by the preamble code currently configured by the base station;

wherein, the N is₀And for the first TA, the t is a time length of one symbol in a communication system in which the base station and the terminal operate.

6. The method of claim 5, wherein the sending, by the terminal to the base station, the second uplink data according to the second TA specifically comprises:

according to the ith uplink timing advance N in the Q uplink timing advances₀Determining a first uplink sending time at + txi, and sending the second uplink data at the first uplink sending time; wherein i is more than or equal to 1 and less than or equal to Q;

if the terminal receives a receiving failure response sent by the base station, the receiving failure response is sent according to N₀+ t × (i +1) determines a second uplink transmission time, and transmits the second uplink data at the second uplink transmission time.

7. The method according to any of claims 1-6, wherein before the terminal receives the first TA transmitted by the base station, the method further comprises:

receiving a system message sent by the base station, wherein the system message comprises a root sequence index number and/or format configuration information of a random access preamble;

determining a random access lead code according to the index number of the root sequence and/or the format configuration information of the random access lead code;

transmitting the random access preamble to the base station.

8. A terminal, comprising:

a receiving unit, configured to receive a first uplink timing advance TA sent by a base station;

a sending unit, configured to send first uplink data to the base station according to the first TA received by the receiving unit;

the receiving unit is further configured to receive a reception failure response sent by the base station; the reception failure response is used for indicating that the base station does not successfully receive the first uplink data;

an updating unit, configured to update the first TA to a second TA, where the second TA is greater than the first TA;

the sending unit is further configured to send second uplink data to the base station according to the second TA;

the receiving unit is further configured to receive a timing advance adjustment coefficient K sent by the base station, where K is an integer greater than or equal to 1 and less than or equal to Q, and Q is a difference between an upper limit of a number of symbols occupied by a random access preamble supported in a communication system in which the terminal and the base station operate and a number of symbols occupied by a preamble currently configured by the base station.

9. The terminal of claim 8, wherein the updating unit is specifically configured to determine that the second TA is N₀+ t × K, where N₀For the first TA, t is a time length of one symbol in a communication system in which the base station and the terminal operate.

10. The terminal of claim 8,

the receiving unit is further configured to receive the second TA sent by the base station;

the updating unit is specifically configured to update the first TA to the received second TA.

11. The terminal according to claim 9, characterized in that the terminal further comprises a determining unit,

the determining unit is configured to determine a first uplink transmission time according to the second TA;

the sending unit is specifically configured to send the second uplink data at the first uplink sending time.

12. The terminal according to claim 8, characterized in that the updating unit is specifically configured to,

according to N₀+ t × Q determines Q uplink timing advances,the second TA comprises the Q uplink timing advances, wherein Q ∈ [1, Q ∈]Q is an integer, and Q is a difference value between an upper limit of the number of symbols occupied by the random access preamble code supported by the communication system in which the terminal and the base station work and the number of symbols occupied by the preamble code currently configured by the base station;

13. The terminal according to claim 12, characterized in that the terminal further comprises a determining unit,

the determining unit is specifically configured to determine an ith uplink timing advance N of the Q uplink timing advances₀+ txi determines a first uplink transmission time;

the sending unit is configured to send the second uplink data at the first uplink sending time; wherein i is more than or equal to 1 and less than or equal to Q;

the receiving unit is configured to receive a reception failure response sent by the base station;

the determination unit is used for determining the N₀+ t (i +1) determining a second uplink transmission time;

the sending unit is configured to send the second uplink data at the second uplink sending time.

14. The terminal according to any of claims 11-13,

the receiving unit is further configured to receive a system message sent by the base station before receiving the first TA sent by the base station, where the system message includes a root sequence index and/or format configuration information of a random access preamble;

the determining unit is further configured to determine a random access preamble according to the root sequence index number and/or format configuration information of the random access preamble;

the sending unit is further configured to send the random access preamble to the base station.

15. A computer-readable storage medium having instructions stored thereon, which, when run on a terminal, cause the terminal to perform the method of any one of claims 1-7.

16. A wireless communications apparatus, comprising: a memory;

the memory has stored therein instructions that, when executed by the terminal, cause the terminal to perform the method of any of claims 1-7.