Patent Publication Number: US-2020281014-A1

Title: Information transmission method and apparatus for grant-free uplinks

Description:
TECHNICAL FIELD 
     The present disclosure relates to a field of wireless communication, and in particular to an information transmission method and an apparatus for grant-free uplinks of a Non-Orthogonal Multiple Access (NOMA) system. 
     BACKGROUND 
     In order to reduce signaling overhead, it has been proposed to utilize grant-free uplinks for information transmission in a NOMA system. In the grant-free uplinks, when a user terminal performs information transmission with a base station, the user terminal transmits, to the base station, uplink access information required for its access to the base station together with data information to be transmitted after accessing the base station. Accordingly, the base station decodes the uplink access information and the data information to obtain the data information. 
     Specifically, in a communication system, when the base station receives the uplink access information and the data information of the user terminal, the base station firstly decodes the uplink access information. If the decoding is performed correctly, the base station processes the received data information. On the other hand, if the decoding cannot be performed correctly, the base station does not process the received data information. 
     SUMMARY OF THE DISCLOSURE 
     According to one aspect of the present disclosure, an information transmission method for grant-free uplinks performed by a user terminal is provided, the method comprising: transmitting access information of the user terminal; receiving response information of a base station to the access information, wherein the response information includes acknowledgement information of the base station to the access information; transmitting service information after receiving the response information to the access information, wherein the service information includes data information. 
     According to another aspect of the present disclosure, an information transmission method for grant-free uplinks performed by a base station is provided, the method comprising: receiving access information of a user terminal; decoding the access information of the user terminal, and transmitting response information if the access information is decoded correctly, wherein the response information includes acknowledgement information of the base station to the access information; receiving service information after transmitting the response information, wherein the service information includes data information. 
     According to another aspect of the present disclosure, a user terminal for grant-free uplinks is provided, the user terminal comprising: a transmitting unit configured to transmit access information of the user terminal; a receiving unit configured to receive response information of a base station to the access information, wherein the response information includes acknowledgement information of the base station to the access information; a determining unit configured to determine whether the receiving unit receives the response information to the access information, the transmitting unit further configured to transmit service information after the determining unit determines that the receiving unit receives the response information to the access information, wherein the service information includes data information. 
     According to another aspect of the present disclosure, a base station for grant-free uplinks is provided, the base station comprising: a receiving unit configured to receive access information of a user terminal; a decoding unit configured to decode the access information of the user terminal; a determining unit configured to determine whether the decoding is performed correctly; a transmitting unit configured to transmit response information after the determining unit determines that the access information of the user terminal is decoded correctly, wherein the response information includes acknowledgement information of the base station to the access information, the receiving unit further configured to receive service information after the transmitting unit transmits the response information, wherein the service information includes data information. 
     With the information transmission method and the apparatus for grant-free uplinks according to the above aspects of the present disclosure, invalid transmission of the service information is avoided, and thus waste of radio resources is reduced and uplink spectral efficiency is improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to explain the technical solution of embodiments of the present disclosure more clearly, accompanying drawings used in description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are merely some of the embodiments of the present disclosure. Those skilled in the art may further obtain other accompanying drawings according to these accompanying drawings without creative effort. 
         FIG. 1  shows a flowchart of an information transmission method for grant-free uplinks performed by a user terminal according to one embodiment of the present disclosure; 
         FIG. 2  shows a schematic diagram of information transmission between a user terminal and a base station according to one example; 
         FIG. 3  shows a schematic diagram of information transmission between a user terminal and a base station according to another example; 
         FIG. 4  shows a schematic diagram of information transmission between a user terminal and a base station according to another example; 
         FIG. 5  shows a schematic diagram of information transmission between a user terminal and a base station according to another example; 
         FIG. 6  shows a schematic diagram of information transmission between a user terminal and a base station according to another example; 
         FIG. 7  shows a flowchart of an information transmission method for grant-free uplinks performed by a base station according to one embodiment of the present disclosure; 
         FIG. 8  shows a schematic structural diagram of a user terminal performing the method shown in  FIG. 1  according to the embodiments of the present disclosure; 
         FIG. 9  shows a schematic structural diagram of a base station performing the method shown in  FIG. 7  according to the embodiments of the present disclosure; 
         FIG. 10  shows a schematic diagram of a hardware structure of a related user equipment according to the embodiments of the present disclosure. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     An information transmission method and an apparatus for grant-free uplinks according to embodiments of the present disclosure will be described below with reference to the accompanying drawings. Like reference numerals refer to like elements throughout the accompanying drawings. It should be understood that the embodiments described herein are merely illustrative and should not be construed as limiting the scope of the present disclosure. Furthermore, the base station may be a fixed station, a NodeB, an eNodeB (eNB), an access point, a transmission point, a reception point, a femto cell, a small cell and the like, which is not limited herein. Furthermore, a User Equipment (UE) described herein may include various types of user terminals, for example, a mobile terminal (or referred to as a mobile station) or a fixed terminal. However, for convenience, the UE and the mobile station sometimes may be used interchangeably hereinafter. 
     According to the information transmission method and the apparatus for grant-free uplinks provided by the embodiments of the present disclosure, the user terminal firstly transmits access information to the base station, and the user terminal transmits service information only after receiving the base station acknowledgement information to the access information, thereby avoiding invalid transmission of the service information, and thus reducing waste of radio resources and improving uplink spectral efficiency. 
     The information transmission method for grant-free uplinks performed by a user terminal according to one embodiment of the present disclosure will be described below with reference to  FIG. 1 .  FIG. 1  illustrates a flowchart of the information transmission method  100  for grant-free uplinks. 
     As shown in  FIG. 1 , in step S 101 , access information of a user terminal is transmitted. According to one example of the embodiment, the access information may include a preamble code (also referred to as a preamble sequence or a random access preamble code) and/or uplink data control information. 
     For example, the preamble code may include a cyclic prefix CP with a length of Tcp and a sequence with a length of Tseq. For a cell formed by a base station, there may be 64 preamble codes. When accessing to the base station, the user terminal selects one of the 64 preamble codes for access to prevent access collisions with other user terminals. 
     Furthermore, the preamble code may further include identification information of the user terminal. The identification information of the user terminal may be, for example, the user terminal&#39;s ID, the user terminal&#39;s physical address (also referred to as Media Access Control (MAC) address), or other information that can uniquely identify the user terminal and the like, to identify the user terminal&#39;s identity. After receiving the preamble code of the user terminal, the base station may obtain the identification information of the user terminal from the preamble code, thereby identifying the user terminal&#39;s identity. 
     As another example, the uplink data control information may include Uplink Control CHannel (UL CCH) information of the user terminal. 
     As described above, the access information transmitted in step S 101  may include both a preamble code and uplink data control information. Alternatively, the access information transmitted in step S 101  may also include only one of a preamble code and uplink data control information. 
     When the access information includes a preamble code and uplink data control information, both the preamble code and the uplink data control information may include the identification information of the user terminal, or one of the two may include the identification information of the user terminal, to identify the user terminal&#39;s identity. 
     Furthermore, when the access information includes only uplink data control information, the uplink data control information may include the identification information of the user terminal. As described above, the identification information of the user terminal may be, for example, the user terminal&#39;s ID, the user terminal&#39;s MAC address, or other information that can uniquely identify the user terminal and the like, to identify the user terminal&#39;s identity. After receiving the uplink data control information of the user terminal, the base station may obtain the identification information of the user terminal from the uplink data control information, thereby identifying the user terminal&#39;s identity. 
     According to another example of this embodiment, the access information in step S 101  may further include first scheduling information for the service information. The service information will be further described in a later step S 103 . 
     According to an example of this embodiment, the first scheduling information may include at least one of modulation and coding information for the service information, information on the number of times of retransmissions for the service information, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, and radio resource information for the service information. After receiving the first scheduling information, the base station may process the service information transmitted by the user terminal according to the first scheduling information. 
     For example, the modulation and coding information for the service information may indicate a modulation and coding mode adopted by the user terminal when transmitting the service information, so that the base station may demodulate and decode the service information according to the modulation and coding information after receiving the service information. 
     As another example, the information on the number of times of retransmissions for the service information may indicate the number of times of retransmissions after the user terminal failing to transmit the service information, so that the base station may perform hybrid feedback retransmission combination on the service information received for multiple times. 
     As yet another example, the transmission power control information for the service information may indicate a transmission power adopted by the user terminal when transmitting the service information, so that the base station may obtain the transmission power for the user terminal, and thereby perform channel measurement or channel estimation. 
     As yet another example, the signature information for the service information may indicate an interleaving mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before interleaving according to the interleaving mode after receiving the service information (this operation may also be referred to as □de-interleaving□). The signature information for the service information may also indicate a scrambling mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before scrambling according to the scrambling mode after receiving the service information (this operation may also be referred to as □de-scrambling□). The signature information for the service information may also indicate a spreading mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before spreading according to the spreading mode after receiving the service information. Certainly, the signature information for the service information is not limited to the interleaving mode, the scrambling mode, and the spreading mode listed herein, and may also indicate other operations that the user terminal performs on the service information when transmitting the service information. 
     As yet another example, the reference signal information for the service information may indicate reference signals of a channel adopted by the user terminal when transmitting the service information, so that the base station may perform channel measurement or channel estimation. 
     As yet another example, the radio resource information for the service information may indicate radio resources occupied by the user terminal when transmitting the service information, so that the base station may receive the service information on the radio resources. 
     Then, in step S 102 , response information of the base station to the access information is received, where the response information includes acknowledgement information (also referred to as □ACK□) of the base station to the access information. In this embodiment, when the base station decodes the access information correctly, the base station may feed back the acknowledgement information to the user terminal. On the other hand, when the base station does not decode the access information correctly, the base station may not feed back any information to the user terminal, or may feed back non-acknowledgment information (also referred to as □NACK□) to the user terminal. 
     According to one example of this embodiment, when the access information transmitted by the user terminal in step S 101  includes a preamble code, the user terminal receives response information of the base station to the preamble code in step S 102 , where the response information includes acknowledgement information of the base station to the preamble code. For example, when the user terminal transmits the preamble code in step S 101 , the base station receives and decodes the preamble code. If the decoding is performed correctly, the base station may feed back acknowledgement information to the user terminal, and the user terminal receives the acknowledgement information of the base station to the preamble code in step S 102 . In this example, a correct decoding may be that the base station obtains the identification information of the user terminal through the decoding and thereby identifies the user terminal&#39;s identity. 
     According to another example of this embodiment, when the access information transmitted by the user terminal in step S 101  includes uplink data control information, the user terminal receives response information of the base station to the uplink data control information in step S 102 , where the response information includes acknowledgement information of the base station to the uplink data control information. For example, when the user terminal transmits the uplink data control information in step S 101 , the base station receives and decodes the uplink data control information. If the decoding is performed correctly, the base station may feed back acknowledgement information to the user terminal, and the user terminal receives the acknowledgement information of the base station to the uplink data control information in step S 102 . 
     According to another example of this embodiment, when the access information transmitted by the user terminal in step S 101  includes a preamble code and uplink data control information, the user terminal receives response information of the base station to the preamble code and the uplink data control information in step S 102 , where the response information includes acknowledgement information of the base station to the preamble code and the uplink data control information. For example, when the user terminal transmits the preamble code and the uplink data control information in step S 101 , the base station receives and decodes the preamble code and the uplink data control information. If the decoding is performed correctly, the base station may feed back acknowledgement information to the user terminal, and the user terminal receives the acknowledgement information of the base station to the preamble code and the uplink data control information in step S 102 . 
     In this example, the base station feeds back the acknowledgement information to the user terminal only after correctly decoding the preamble code and the uplink data control information, respectively. 
     In addition, according to another example of this embodiment, the response information received by the user terminal in step S 102  may further include Timing Advance (TA) information transmitted by the base station to the user terminal. For example, the base station may transmit a timing advance command to the user terminal to inform the user terminal of the amount of time of the timing advance, thereby avoiding transmission delay caused by the distance between the base station and the user terminal, and reducing interference between the user terminal and other user terminals. 
     Furthermore, according to another example of this embodiment, when the user terminal transmits the first scheduling information for the service information in step S 101 , the base station receives the first scheduling information for the service information. Then, the base station generates modified scheduling information according to the first scheduling information for the service information, and feeds back the modified scheduling information to the user terminal by including it in the response information. Accordingly, the user terminal receives the modified scheduling information in step S 102 . 
     For example, when the user terminal transmits scheduling information for the service information in step S 101 , the base station receives the scheduling information for the service information. Then, the base station may flexibly modify the received scheduling information based on load conditions, channel conditions and the like in the cell to obtain the modified scheduling information. The base station may then feed back the modified scheduling information to the user terminal by including it in the response information. Accordingly, the user terminal receives the modified scheduling information in step S 102 . Then, the user terminal transmits the service information to the base station based on the modified scheduling information in a later step S 103 . 
     For example, the scheduling information transmitted by the user terminal in step S 101  may include the modulation and coding information for the service information. When the user terminal transmits the modulation and coding information for the service information in step S 101 , the base station receives the modulation and coding information for the service information. Then, the base station may select a preferable coding and modulation mode for the user terminal based on load conditions, channel conditions and the like in the cell, to obtain information on the preferable modulation and coding mode. Then, the base station may feed back the information on the preferable modulation and coding mode to the user terminal by including it in the response information. Accordingly, the user terminal receives the information on the preferable modulation and coding mode in step S 102 . Then, the user terminal transmits the service information to the base station based on the preferable modulation and coding mode in a later step S 103 . 
     Similarly, the scheduling information transmitted by the user terminal in step S 101  may include information on the number of times of retransmissions for the service information, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, or radio resource information for the service information and the like. That is, the base station may select the number of times of retransmissions, a transmission power, a signature mode, radio resources and the like that are preferable for the user terminal based on load conditions, channel conditions and the like in the cell. 
     Certainly, the base station may also select a modulation and coding mode, the number of times of retransmissions, a transmission power, a signature mode, radio resources and the like that are inferior for the user terminal based on load conditions, channel conditions and the like in the cell, which sacrifices part of the user terminal performance while realizes an overall performance improvement of the cell. 
     According to another example of this embodiment, the base station may further transmit second scheduling information to the user terminal. For example, when the user terminal transmits the first scheduling information for the service information in step S 101 , the response information received by the user terminal in step S 102  may further include the second scheduling information. Specifically, the second scheduling information may be supplementary information of the base station to the first scheduling information. 
     For example, when the user terminal transmits only the modulation and coding information in the scheduling information for the service information in step S 101 , the response information received by the user terminal in step S 102  may include other information in the scheduling information for the service information, such as information on the number of times of retransmissions, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, radio resource information for the service information, and the like. 
     According to another example of this embodiment, when the user terminal transmits the first scheduling information for the service information in step S 101 , the response information received by the user terminal in step S 102  may include not only the modified first scheduling information, but also the second scheduling information. 
     For example, when the user terminal transmits only the modulation and coding information in the scheduling information for the service information in step S 101 , the base station modifies the modulation and coding information after receiving it to obtain modified modulation and coding information, and thus the response information received by the user terminal in step S 102  may include not only other information in the scheduling information for the service information, such as information on the number of times of retransmissions, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, radio resource information for the service information and the like, but also the modified modulation and coding information. 
     The specific content of the response information received by the user terminal in step S 102  has been described above, and the time that the user terminal receives the response information in step S 102  will be described below. In this embodiment, the time that the user terminal receives the response information in step S 102  may be a moment or a time window. 
     According to an example of this embodiment, the user terminal may transmit information indicating a first time interval to the base station when transmitting the access information of the user terminal in step S 101 . The base station may transmit the response information to the access information after the first time interval according to the received access information. For example, after receiving the access information, the base station may transmit the response information of the base station to the access information at a moment or any moment in a time window after a predetermined time interval. Accordingly, after step S 101 , the user terminal may receive the response information of the base station to the access information at a moment or in a time window after the first time interval. 
     According to another example of this embodiment, the user terminal may also determine a periodic information-receiving window, and receive the response information of the base station to the access information in a first information-receiving window after transmitting the access information of the user terminal in step S 101 . The information-receiving window may be a time window for transmitting signaling between the user terminal and the base station. Alternatively, the information-receiving window may be a time period. 
     In this example, the signaling transmitted in the time window may include user terminal-specific signaling information transmitted by the base station to the user terminal, or group-specific signaling information of a user terminal group to which the user terminal belongs. The user terminal-specific signaling may include cell reference signals, downlink control information and the like; the group-specific signaling information may include channel quality conditions, resource allocation conditions, user terminal grouping conditions, and so on. 
     The user terminal group mentioned herein may include one or more user terminals transmitting signaling information in a same time slot, or may include one or more user terminals transmitting signaling information in a same frequency band, or may be one or more user terminals that transmit access information within a time period between two adjacent information-receiving windows. 
     Furthermore, according to another example of this embodiment, the base station may transmit the response information to the access information on an existing downlink channel, or may transmit the response information to the access information on a dedicated channel. 
     Specifically, the base station may transmit the response information to the access information on a downlink control channel, a downlink data channel, or a response information transmission channel. Accordingly, the user terminal receives the response information of the base station to the access information on the corresponding downlink control channel, the downlink data channel, or the response information transmission channel in step S 102 . 
     For example, the downlink control channel may include a Physical Downlink Control Channel (PDCCH), a Physical Multicast Channel (PMCH), a Physical Broadcast Channel (PBCH), a Physical Control Format Indicator Channel (PCFICH), and a Physical HARQ Indicator Channel (PHICH) and the like; the downlink data channel may include a Physical Downlink Shared Channel (PDSCH) and the like; the response information transmission channel may include a channel dedicated to receive the response information. 
     According to another example of this embodiment, in step S 102 , the user terminal may determine radio resources carrying the response information based on at least one of the identification information of the user terminal and information on radio resources for transmitting the uplink data control information, and then receive the response information of the base station to the access information on the radio resources. 
     For example, the base station determines, for user terminals in the cell, a radio resource pool for transmitting response information. After receiving access information of a certain user terminal, the base station selects radio resources for the user terminal, and then transmits response information to the access information of this user terminal on the radio resources. In step S 102 , the user terminal may deduce index numbers of radio resources used by the base station based on the identification information of the user terminal, and then receive the response information on the radio resources corresponding to the index numbers. 
     As another example, the base station determines, for user terminals in the cell, a radio resource pool for transmitting response information. After receiving access information of a user terminal, the base station selects radio resources for the user terminal, and then transmits response information to the access information of this user terminal on the radio resources. In step S 102 , the user terminal may deduce index numbers of radio resources used by the base station not only based on the identification information of the user terminal but also based on the information on radio resources for transmitting the uplink data control information, and then receive the response information on the radio resources corresponding to the index numbers. 
     In this example, the base station may use frequency resources for transmitting the uplink data control information as frequency resources for transmitting the response information. That is, frequency resources for transmitting the uplink data control information and frequency resources for transmitting the response information may be identical. Alternatively, the base station may also use a subframe pattern corresponding to radio resources for transmitting the uplink data control information as a subframe pattern for transmitting the response information. That is, a subframe pattern for transmitting the uplink data control information and a subframe pattern for transmitting the response information may be identical. 
     Then, in step S 103 , after the response information to the access information is received, the service information is transmitted, where the service information includes data information. In this embodiment, the user terminal transmits the service information only after receiving the response information of the base station to the access information, thereby avoiding waste of radio resources. 
     According to one example of this embodiment, if the access information transmitted by the user terminal in step S 101  includes a preamble code and then the user terminal receives response information of the base station to the preamble code in step S 102 , the user terminal may transmit the data information in step S 103 . 
     According to another example of this embodiment, if the access information transmitted by the user terminal in step S 101  includes uplink data control information and then the user terminal receives response information of the base station to the uplink data control information in step S 102 , the user terminal may transmit the data information in step S 103 . 
     According to another example of this embodiment, if the access information transmitted by the user terminal in step S 101  includes a preamble code and uplink data control information and then the user terminal receives response information of the base station to the preamble code and the uplink data control information in step S 102 , the user terminal may transmit the data information in step S 103 . 
     According to another example of this embodiment, if the access information transmitted by the user terminal in step S 101  includes a preamble code and then the user terminal receives response information of the base station to the preamble code in step S 102 , the user terminal may also transmit uplink data control information and the data information in step S 103 . 
     According to another example of this embodiment, if the access information transmitted by the user terminal in step S 101  includes a preamble code and then the user terminal receives response information of the base station to the preamble code in step S 102 , the user terminal may also transmit uplink data control information firstly, receive response information of the base station to the uplink data control information that includes acknowledgement information of the base station to the uplink data control information, and then transmit service information after receiving the response information of the uplink data control information in step S 103 . 
     The specific process of the user terminal transmitting the service information in step S 103  has been described above, and the time that the user terminal transmits the service information in step S 103  will be described below. 
     According to one example of this embodiment, the user terminal may transmit information indicating a second time interval to the base station when transmitting the access information of the user terminal in step S 101 . After receiving the response information, the user terminal may transmit the service information to the base station after the second time interval, so that the base station receives the service information transmitted by the user terminal at a corresponding moment. For example, after receiving the response information, the user terminal may transmit the service information at a moment or any moment in a time window after a predetermined time interval. 
     According to another example of this embodiment, the user terminal may not transmit information indicating the second time interval to the base station. Specifically, after receiving the response information, the user terminal may transmit the service information after a third time interval. 
     As for the □first time interval□, the □second time interval□ and the □third time interval□ mentioned above, time lengths corresponding to them may be the same or different, which is not limited by this embodiment. 
     Steps S 101 - 103  have been described in detail above, and examples of the method  100  will be further described below with reference to  FIGS. 2-6 . 
       FIG. 2  shows a schematic diagram of information transmission between a user terminal and a base station according to one example. In the example shown in  FIG. 2 , the access information includes a preamble code  201  and the service information includes data information  203 . As shown in  FIG. 2 , firstly, as shown by arrow A, the user terminal transmits the preamble code  201  to the base station. Then, as shown by arrow B, the user terminal receives, from the base station, response information  202  of the base station to the preamble code  201 . Finally, as shown by arrow C, the user terminal transmits the data information  203  to the base station. 
       FIG. 3  shows a schematic diagram of information transmission between a user terminal and a base station according to another example. In the example shown in  FIG. 3 , the access information includes uplink data control information  301  and the service information includes data information  303 . As shown in  FIG. 3 , firstly, as shown by arrow A, the user terminal transmits the uplink data control information  301  to the base station. Then, as shown by arrow B, the user terminal receives, from the base station, response information  302  of the base station to the uplink data control information  301 . Finally, as shown by arrow C, the user terminal transmits the data information  303  to the base station. 
       FIG. 4  shows a schematic diagram of information transmission between a user terminal and a base station according to another example. In the example shown in  FIG. 4 , the access information includes a preamble code  401  and uplink data control information  402 , and the service information includes data information  404 . As shown in  FIG. 4 , firstly, as shown by arrow A, the user terminal transmits the preamble code  401  and the uplink data control information  402  to the base station. Then, as shown by arrow B, the user terminal receives, from the base station, response information  403  of the base station to the preamble code  401  and the uplink data control information  402 . Finally, as shown by arrow C, the user terminal transmits the data information  404  to the base station. 
       FIG. 5  shows a schematic diagram of information transmission between a user terminal and a base station according to another example. In the example shown in  FIG. 5 , the access information includes a preamble code  501 , and the service information includes uplink data control information  503  and data information  504 . As shown in  FIG. 5 , firstly, as shown by arrow A, the user terminal transmits the preamble code  501  to the base station. Then, as shown by arrow B, the user terminal receives, from the base station, response information  502  of the base station to the preamble code  501 . Finally, as shown by arrow C, the user terminal transmits the uplink data control information  503  and the data information  504  to the base station. 
       FIG. 6  shows a schematic diagram of information transmission between a user terminal and a base station according to another example. In the example shown in  FIG. 6 , the access information includes a preamble code  601  and the service information includes data information  605 . As shown in  FIG. 6 , firstly, as shown by arrow A, the user terminal transmits the preamble code  601  to the base station. Then, as shown by arrow B, the user terminal receives, from the base station, response information  602  of the base station to the preamble code  601 . Finally, as shown by arrow C, the user terminal firstly transmits uplink data control information  603  to the base station, receives response information  604  of the base station to the uplink data control information  603 , and finally transmits the data information  605  after receiving the response information  604  of the uplink data control information. 
     According to the information transmission method for grant-free uplinks performed by a user terminal provided by the embodiments of the present disclosure, the user terminal firstly transmits the access information to the base station, and the user terminal transmits the service information only after receiving the base station acknowledgement information to the access information, thereby avoiding invalid transmission of the service information, and thus reducing waste of radio resources and improving uplink spectral efficiency. 
     An information transmission method for grant-free uplinks performed by a base station according to one embodiment of the present disclosure will be described below with reference to  FIG. 7 .  FIG. 7  shows a flowchart of the information transmission method  700  for grant-free uplinks. 
     As shown in  FIG. 7 , in step S 701 , access information of a user terminal is received. According to one example of this embodiment, the access information may include a preamble code (also referred to as a preamble sequence or a random access preamble code) and/or uplink data control information. 
     For example, the preamble code may include a cyclic prefix CP with a length of Tcp and a sequence with a length of Tseq. For a cell formed by a base station, there may be 64 preamble codes. When accessing to the base station, the user terminal selects one of the 64 preamble codes for access to prevent access collisions with other user terminals. 
     Furthermore, the preamble code may further include identification information of the user terminal. The identification information of the user terminal may be, for example, the user terminal&#39;s ID, the user terminal&#39;s physical address (also referred to as Media Access Control (MAC) address), or other information that can uniquely identify the user terminal and the like, to identify the user terminal&#39;s identity. After receiving the preamble code of the user terminal, the base station may obtain the identification information of the user terminal from the preamble code, thereby identifying the user terminal&#39;s identity. 
     As another example, the uplink data control information may include Uplink Control CHannel (ULCCH) information of the user terminal. 
     As described above, the access information received in step S 701  may include both a preamble code and uplink data control information. Alternatively, the access information received in step S 701  may also include only one of a preamble code and uplink data control information. 
     When the access information includes a preamble code and uplink data control information, both the preamble code and the uplink data control information may include the identification information of the user terminal, or one of the two may include the identification information of the user terminal, to identify the user terminal&#39;s identity. 
     Furthermore, when the access information includes only uplink data control information, the uplink data control information may include the identification information of the user terminal. As described above, the identification information of the user terminal may be, for example, the user terminal&#39;s ID, the user terminal&#39;s MAC address, or other information that can uniquely identify the user terminal and the like, to identify the user terminal&#39;s identity. After receiving the uplink data control information of the user terminal, the base station may obtain the identification information of the user terminal from the uplink data control information, thereby identifying the user terminal&#39;s identity. 
     According to another example of this embodiment, the access information in step S 701  may further include first scheduling information for the service information. The service information will be further described in a later step S 703 . 
     According to an example of this embodiment, the first scheduling information may include at least one of modulation and coding information for the service information, information on the number of times of retransmissions for the service information, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, and radio resource information for the service information. After receiving the first scheduling information, the base station may process the service information transmitted by the user terminal according to the first scheduling information. 
     For example, the modulation and coding information for the service information may indicate a modulation and coding mode adopted by the user terminal when transmitting the service information, so that the base station may demodulate and decode the service information according to the modulation and coding information after receiving the service information. 
     As another example, the information on the number of times of retransmissions for the service information may indicate the number of times of retransmissions after the user terminal failing to transmit the service information, so that the base station may perform hybrid feedback retransmission combination on the service information received for multiple times. 
     As yet another example, the transmission power control information for the service information may indicate a transmission power adopted by the user terminal when transmitting the service information, so that the base station may obtain the transmission power for the user terminal, and thereby perform channel measurement or channel estimation. 
     As yet another example, the signature information for the service information may indicate an interleaving mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before interleaving according to the interleaving mode after receiving the service information (this operation may also be referred to as □de-interleaving□). The signature information for the service information may also indicate a scrambling mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before scrambling according to the scrambling mode after receiving the service information (this operation may also be referred to as □de-scrambling□). The signature information for the service information may also indicate a spreading mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before spreading according to the spreading mode after receiving the service information. Certainly, the signature information for the service information is not limited to the interleaving mode, the scrambling mode, and the spreading mode listed herein, and may also indicate other operations that the user terminal performs on the service information when transmitting the service information. 
     As yet another example, the reference signal information for the service information may indicate reference signals of a channel adopted by the user terminal when transmitting the service information, so that the base station may perform channel measurement or channel estimation. 
     As yet another example, the radio resource information for the service information may indicate radio resources occupied by the user terminal when transmitting the service information, so that the base station may receive the service information on the radio resources. 
     Then, in step S 702 , the access information of the user terminal is decoded, and response information is transmitted if decoded correctly, where the response information includes acknowledgement information (also referred to as □ACK□) of the base station to the access information. In this embodiment, when the base station decodes the access information correctly, the base station may feed back the acknowledgement information to the user terminal. On the other hand, when the base station does not decode the access information correctly, the base station may not feed back any information to the user terminal, or may feed back non-acknowledgment information (also referred to as □NACK□) to the user terminal. 
     According to one example of this embodiment, when the access information received by the base station in step S 701  includes a preamble code, the base station decodes the preamble code of the user terminal in step S 702  and transmits response information if decoding correctly, where the response information includes acknowledgement information of the base station to the preamble code. For example, after the base station receiving the preamble code in step S 701 , the base station decodes the preamble code in step S 702  and feeds back acknowledgement information to the user terminal if decoding correctly. In this example, a correct decoding may be that the base station obtains the identification information of the user terminal through the decoding and thereby identifies the user terminal&#39;s identity. 
     According to another example of this embodiment, when the access information received by the base station in step S 701  includes uplink data control information, the base station decodes the uplink data control information of the user terminal in step S 702  and transmits response information if decoding correctly, where the response information includes acknowledgement information of the base station to the uplink data control information. For example, after the base station receives the uplink data control information in step S 701 , the base station decodes the uplink data control information in step S 702  and feeds back acknowledgement information to the user terminal if decoding correctly. 
     According to another example of this embodiment, when the access information received by the base station in step S 701  includes a preamble code and uplink data control information, the base station decodes the preamble code and the uplink data control information of the user terminal in step S 702  and transmits response information if decoding correctly, where the response information includes acknowledgement information of the base station to the preamble code and the uplink data control information. For example, after the base station receives the preamble code and the uplink data control information in step S 701 , the base station decodes them in step S 702  and feeds back acknowledgement information to the user terminal if decoding correctly. 
     In this example, the base station feeds back the acknowledgement information to the user terminal only after correctly decoding the preamble code and the uplink data control information, respectively, in step S 702 . 
     In addition, according to another example of this embodiment, the response information transmitted by the base station in step S 702  may further include Timing Advance (TA) information transmitted by the base station to the user terminal. For example, the base station may transmit a timing advance command to the user terminal to inform the user terminal of the amount of time of the timing advance, thereby avoiding transmission delay caused by the distance between the base station and the user terminal, and reducing interference between the user terminal and other user terminals. 
     Furthermore, according to another example of this embodiment, when the base station receives the first scheduling information for the service information in step S 701 , the base station generates modified scheduling information according to the first scheduling information for the service information, and feeds back the modified scheduling information to the user terminal in step S 702  by including it in the response information. 
     For example, when the user terminal transmits scheduling information for the service information, the base station receives the scheduling information for the service information. Then, the base station may flexibly modify the received scheduling information based on load conditions, channel conditions and the like in the cell to obtain the modified scheduling information. The base station may then feed back the modified scheduling information to the user terminal by including it in the response information. Accordingly, the user terminal receives the modified scheduling information. Then, the user terminal may transmit the service information to the base station based on the modified scheduling information. 
     For example, the scheduling information received by the base station in step S 701  may include the modulation and coding information for the service information, and then the base station may select a preferable coding and modulation mode for the user terminal based on load conditions, channel conditions and the like in the cell, to obtain information on the preferable modulation and coding mode. Then, the base station may feed back the information on the preferable modulation and coding mode to the user terminal in step S 702  by including it in the response information. After receiving the information on the preferable modulation and coding mode, the user terminal may transmit the service information to the base station based on the preferable modulation and coding mode. 
     Similarly, the scheduling information received by the base station in step S 701  may include information on the number of times of retransmissions for the service information, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, or radio resource information for the service information and the like. That is, the base station may select the number of times of retransmissions, a transmission power, a signature mode, radio resources and the like that are preferable for the user terminal based on load conditions, channel conditions and the like in the cell. 
     Certainly, the base station may also select a modulation and coding mode, the number of times of retransmissions, a transmission power, a signature mode, radio resources and the like that are inferior for the user terminal based on load conditions, channel conditions and the like in the cell, which sacrifices part of the user terminal performance while realizes an overall performance improvement of the cell. 
     According to another example of this embodiment, the base station may further transmit second scheduling information to the user terminal in step S 702 . For example, when the base station receives the first scheduling information for the service information in step S 701 , the base station may generate the second scheduling information, and the response information transmitted in step S 702  may further include the second scheduling information. Specifically, the second scheduling information may be supplementary information of the base station to the first scheduling information. 
     For example, when the base station receives only the modulation and coding information in the scheduling information for the service information in step S 701 , the response information transmitted by the base station in step S 702  may include other information in the scheduling information for the service information, such as information on the number of times of retransmissions, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, radio resource information for the service information, and the like. 
     According to another example of this embodiment, when the base station receives the first scheduling information for the service information in step S 701 , the response information transmitted by the base station in step S 702  may include not only the modified first scheduling information, but also the second scheduling information. 
     For example, when the base station receives only the modulation and coding information in the scheduling information for the service information in step S 701 , the base station modifies the modulation and coding information after receiving it to obtain modified modulation and coding information, and thus the response information transmitted by the base station in step S 702  may include not only other information in the scheduling information for the service information, such as information on the number of times of retransmissions, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, radio resource information for the service information and the like, but also the modified modulation and coding information. 
     The specific content of the response information transmitted by the base station in step S 702  has been described above, and the time that the base station transmits the response information in step S 702  will be described below. In this embodiment, the time that the base station transmits the response information in step S 702  may be a moment or a time window. 
     According to an example of this embodiment, the base station may further receive information indicating a first time interval in step S 701 . After receiving the access information, the base station may transmit the response information to the access information after the first time interval. For example, after receiving the access information, the base station may transmit the response information of the base station to the access information at a moment or any moment in a time window after a predetermined time interval. Accordingly, the user terminal may receive the response information of the base station to the access information at a moment or in a time window after the first time interval. 
     According to another example of this embodiment, the base station may also determine a periodic information-receiving window, and transmit the response information of the base station to the access information in a first information-receiving window after receiving the access information of the user terminal in step S 701 . The information-receiving window may be a time window for transmitting signaling between the user terminal and the base station. Alternatively, the information-receiving window may be a time period. 
     In this example, the signaling transmitted in the time window may include user terminal-specific signaling information transmitted by the base station to the user terminal, or group-specific signaling information of a user terminal group to which the user terminal belongs. The user terminal-specific signaling may include cell reference signals, downlink control information and the like; the group-specific signaling information may include channel quality conditions, resource allocation conditions, user terminal grouping conditions, and so on. 
     The user terminal group mentioned herein may include one or more user terminals transmitting signaling information in a same time slot, or may include one or more user terminals transmitting signaling information in a same frequency band, or may be one or more user terminals that transmit access information within a time period between two adjacent information-receiving windows. 
     Furthermore, according to another example of this embodiment, the base station may transmit the response information to the access information on an existing downlink channel, or may transmit the response information to the access information on a dedicated channel. 
     Specifically, in step S 702 , the base station may transmit the response information to the access information on a downlink control channel, a downlink data channel, or a response information transmission channel. Accordingly, the user terminal receives the response information of the base station to the access information on the corresponding downlink control channel, the downlink data channel, or the response information transmission channel. 
     For example, the downlink control channel may include a Physical Downlink Control Channel (PDCCH), a Physical Multicast Channel (PMCH), a Physical Broadcast Channel (PBCH), a Physical Control Format Indicator Channel (PCFICH), and a Physical HARQ Indicator Channel (PHICH) and the like; the downlink data channel may include a Physical Downlink Shared Channel (PDSCH) and the like; the response information transmission channel may include a channel dedicated to receive the response information. 
     According to another example of this embodiment, in step S 702 , the base station may determine radio resources carrying the response information based on at least one of the identification information of the user terminal and information on radio resources for transmitting the uplink data control information, and then transmit the response information of the base station to the access information on the radio resources. 
     For example, the base station determines, for user terminals in the cell, a radio resource pool for transmitting response information. After receiving access information of a user terminal, the base station selects radio resources for the user terminal, and then transmits response information to the access information of this user terminal on the radio resources. In step S 702 , the base station may deduce index numbers of radio resources used by the base station based on the identification information of the user terminal, and then transmit the response information on the radio resources corresponding to the index numbers. 
     As another example, the base station determines, for user terminals in the cell, a radio resource pool for transmitting response information. After receiving access information of a user terminal, the base station selects radio resources for the user terminal, and then transmits response information to the access information of this user terminal on the radio resources. In step S 702 , the base station may deduce index numbers of radio resources used by the base station not only based on the identification information of the user terminal but also based on the information on radio resources for transmitting the uplink data control information, and then transmit the response information on the radio resources corresponding to the index numbers. 
     In this example, the base station may use frequency resources for transmitting the uplink data control information as frequency resources for transmitting the response information. That is, frequency resources for transmitting the uplink data control information and frequency resources for transmitting the response information may be identical. Alternatively, the base station may also use a pattern corresponding to radio resources for transmitting the uplink data control information as a subframe pattern for transmitting the response information. That is, a subframe pattern for transmitting the uplink data control information and a subframe pattern for transmitting the response information may be identical. 
     In addition, according to another example of this embodiment, in step S 702 , the base station may transmit response information to each user terminal separately, and alternatively, the base station may also transmit response information of a group of user terminals at the same time. The □group of user terminals□ herein may be the □user terminal group□ described above. 
     Then, in step S 703 , after transmitting the response information, the service information is received, where the service information includes data information. In this embodiment, the user terminal transmits the service information only after receiving the response information of the base station to the access information, thereby avoiding waste of radio resources. Accordingly, the base station receives the service information only after transmitting the response information. 
     According to one example of this embodiment, if the access information received by the base station in step S 701  includes a preamble code and then the base station transmits response information of the base station to the preamble code in step S 702 , the base station may receive the data information in step S 703 . 
     According to another example of this embodiment, if the access information received by the base station in step S 701  includes uplink data control information and then the base station transmits response information of the base station to the uplink data control information in step S 702 , the base station may receive the data information in step S 703 . 
     According to another example of this embodiment, if the access information received by the base station in step S 701  includes a preamble code and uplink data control information and then the base station transmits response information of the base station to the preamble code and the uplink data control information in step S 702 , the base station may receive the data information in step S 703 . 
     According to another example of this embodiment, if the access information received by the base station in step S 701  includes a preamble code and then the base station transmits response information of the base station to the preamble code in step S 702 , the base station may also receive uplink data control information and the data information in step S 703 . 
     According to another example of this embodiment, if the access information received by the base station in step S 701  includes a preamble code and then the base station transmits response information of the base station to the preamble code in step S 702 , the base station may also receive uplink data control information firstly, transmit response information to the uplink data control information that includes acknowledgement information of the base station to the uplink data control information, and then receive service information after transmitting the response information of the uplink data control information in step S 703 . 
     The specific process of the base station receiving the service information in step S 703  has been described above, and the time that the base station receives the service information in step S 703  will be described below. 
     According to one example of this embodiment, the base station may also receive information indicating a second time interval when receiving the access information of the user terminal in step S 701 . After receiving the response information, the user terminal may transmit the service information to the base station after the second time interval, so that the base station receives the service information transmitted by the user terminal at a corresponding moment. For example, after receiving the response information, the user terminal may transmit the service information at a moment or any moment in a time window after a predetermined time interval. 
     As for the □first time interval□ and the □second time interval□ mentioned above, time lengths corresponding to them may be the same or different, which is not limited by this embodiment. 
     Steps S 701 - 703  have been described in detail above, and examples of the method  700  may be further described with reference to  FIGS. 2-6 , which will not be repeatedly described herein. 
     According to the information transmission method for grant-free uplinks performed by a base station provided by the embodiments of the present disclosure, the user terminal firstly transmits the access information to the base station, and the user terminal transmits the service information only after receiving the base station acknowledgement information to the access information, thereby avoiding invalid transmission of the service information, and thus reducing waste of radio resources and improving uplink spectral efficiency. 
     A user terminal performing the method  100  shown in  FIG. 1  according to embodiments of the present disclosure will be described below with reference to  FIG. 8 .  FIG. 8  shows a schematic structural diagram of the user terminal  800  performing the method  100  shown in  FIG. 1 . 
     As shown in  FIG. 8 , the user terminal  800  includes a transmitting unit  801  configured to transmit access information of the user terminal. The user terminal  800  further includes a receiving unit  802  configured to receive response information of a base station to the access information, where the response information includes acknowledgement information of the base station to the access information. Moreover, the transmitting unit  801  is further configured to transmit service information after the receiving unit  802  receives the response information to the access information, where the service information includes data information. The user terminal  800  may further include other components in addition to these three units. However, since these components are not related to the content of the embodiments of the present disclosure, illustration and description thereof are omitted herein. Furthermore, since specific details of the following operations performed by the user terminal  800  according to the embodiments of the present disclosure are the same as those described above with reference to  FIGS. 2-6 , repeated descriptions of the same details are omitted herein to avoid repetition. 
     According to one example of this embodiment, the access information may include a preamble code (also referred to as a preamble sequence or a random access preamble code) and/or uplink data control information. 
     For example, the preamble code may include a cyclic prefix CP with a length of Tcp and a sequence with a length of Tseq. For a cell formed by a base station, there may be 64 preamble codes. When accessing to the base station, the user terminal selects one of the 64 preamble codes for access to prevent access collisions with other user terminals. 
     Furthermore, the preamble code may further include identification information of the user terminal. The identification information of the user terminal may be, for example, the user terminal&#39;s ID, the user terminal&#39;s physical address (also referred to as Media Access Control (MAC) address), or other information that can uniquely identify the user terminal and the like, to identify the user terminal&#39;s identity. After receiving the preamble code of the user terminal, the base station may obtain the identification information of the user terminal from the preamble code, thereby identifying the user terminal&#39;s identity. 
     As another example, the uplink data control information may include Uplink Control CHannel (ULCCH) information of the user terminal. 
     As described above, the access information transmitted by the transmitting unit  801  may include both a preamble code and uplink data control information. Alternatively, the access information transmitted by the transmitting unit  801  may also include only one of a preamble code and uplink data control information. 
     When the access information includes a preamble code and uplink data control information, both the preamble code and the uplink data control information may include the identification information of the user terminal, or one of the two may include the identification information of the user terminal, to identify the user terminal&#39;s identity. 
     Furthermore, when the access information includes only uplink data control information, the uplink data control information may include the identification information of the user terminal. As described above, the identification information of the user terminal may be, for example, the user terminal&#39;s ID, the user terminal&#39;s MAC address, or other information that can uniquely identify the user terminal and the like, to identify the user terminal&#39;s identity. After receiving the uplink data control information of the user terminal, the base station may obtain the identification information of the user terminal from the uplink data control information, thereby identifying the user terminal&#39;s identity. 
     According to another example of this embodiment, the access information transmitted by the transmitting unit  801  may further include first scheduling information for the service information. The service information will be further described later. 
     According to an example of this embodiment, the first scheduling information may include at least one of modulation and coding information for the service information, information on the number of times of retransmissions for the service information, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, and radio resource information for the service information. After receiving the first scheduling information, the base station may process the service information transmitted by the user terminal according to the first scheduling information. 
     For example, the modulation and coding information for the service information may indicate a modulation and coding mode adopted by the user terminal when transmitting the service information, so that the base station may demodulate and decode the service information according to the modulation and coding information after receiving the service information. 
     As another example, the information on the number of times of retransmissions for the service information may indicate the number of times of retransmissions after the user terminal failing to transmit the service information, so that the base station may perform hybrid feedback retransmission combination on the service information received for multiple times. 
     As yet another example, the transmission power control information for the service information may indicate a transmission power adopted by the user terminal when transmitting the service information, so that the base station may obtain the transmission power for the user terminal, and thereby perform channel measurement or channel estimation. 
     As yet another example, the signature information for the service information may indicate an interleaving mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before interleaving according to the interleaving mode after receiving the service information (this operation may also be referred to as □de-interleaving□). The signature information for the service information may also indicate a scrambling mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before scrambling according to the scrambling mode after receiving the service information (this operation may also be referred to as □de-scrambling□). The signature information for the service information may also indicate a spreading mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before spreading according to the spreading mode after receiving the service information. Certainly, the signature information for the service information is not limited to the interleaving mode, the scrambling mode, and the spreading mode listed herein, and may also indicate other operations that the user terminal performs on the service information when transmitting the service information. 
     As yet another example, the reference signal information for the service information may indicate reference signals of a channel adopted by the user terminal when transmitting the service information, so that the base station may perform channel measurement or channel estimation. 
     As yet another example, the radio resource information for the service information may indicate radio resources occupied by the user terminal when transmitting the service information, so that the base station may receive the service information on the radio resources. 
     Then, the receiving unit  802  receives the response information of the base station to the access information, where the response information includes acknowledgement information (also referred to as □ACK□) of the base station to the access information. In this embodiment, when the base station decodes the access information correctly, the base station may feed back the acknowledgement information to the user terminal. On the other hand, when the base station does not decode the access information correctly, the base station may not feed back any information to the user terminal, or may feed back non-acknowledgment information (also referred to as □NACK□) to the user terminal. 
     According to one example of this embodiment, when the access information transmitted by the transmitting unit  801  includes a preamble code, the receiving unit  802  receives response information of the base station to the preamble code, where the response information includes acknowledgement information of the base station to the preamble code. For example, when the transmitting unit  801  transmits the preamble code, the base station receives and decodes the preamble code. If the decoding is performed correctly, the base station may feed back the acknowledgement information to the user terminal, and the receiving unit  802  receives the acknowledgement information of the base station to the preamble code. In this example, a correct decoding may be that the base station obtains the identification information of the user terminal through the decoding and thereby identifies the user terminal&#39;s identity. 
     According to another example of this embodiment, when the access information transmitted by the transmitting unit  801  includes uplink data control information, the receiving unit  802  receives response information of the base station to the uplink data control information, where the response information includes acknowledgement information of the base station to the uplink data control information. For example, when the transmitting unit  801  transmits the uplink data control information, the base station receives and decodes the uplink data control information. If the decoding is performed correctly, the base station may feed back acknowledgement information to the user terminal, and the receiving unit  802  receives the acknowledgement information of the base station to the uplink data control information. 
     According to another example of this embodiment, when the access information transmitted by transmitting unit  801  includes a preamble code and uplink data control information, the receiving unit  802  receives response information of the base station to the preamble code and the uplink data control information, where the response information includes acknowledgement information of the base station to the preamble code and the uplink data control information. For example, when the transmitting unit  801  transmits the preamble code and the uplink data control information, the base station receives and decodes the preamble code and the uplink data control information. If the decoding is performed correctly, the base station may feed back acknowledgement information to the user terminal, and the receiving unit  802  receives the acknowledgement information of the base station to the preamble code and the uplink data control information. 
     In this example, the base station feeds back the acknowledgement information to the user terminal only after correctly decoding the preamble code and the uplink data control information, respectively. 
     In addition, according to another example of this embodiment, the response information received by the receiving unit  802  may further include Timing Advance (TA) information transmitted by the base station to the user terminal. For example, the base station may transmit a timing advance command to the user terminal to inform the user terminal of the amount of time of the timing advance, thereby avoiding transmission delay caused by the distance between the base station and the user terminal, and reducing interference between the user terminal and other user terminals. 
     Furthermore, according to another example of this embodiment, when the transmitting unit  801  transmits the first scheduling information for the service information, the base station receives the first scheduling information for the service information. Then, the base station generates modified scheduling information according to the first scheduling information for the service information, and feeds back the modified scheduling information to the user terminal by including it in the response information. Accordingly, the receiving unit  802  receives the modified scheduling information. 
     For example, when the transmitting unit  801  transmits scheduling information for the service information, the base station receives the scheduling information for the service information. Then, the base station may flexibly modify the received scheduling information based on load conditions, channel conditions and the like in the cell to obtain the modified scheduling information. The base station may then feed back the modified scheduling information to the user terminal by including it in the response information. Accordingly, the receiving unit  802  receives the modified scheduling information. Then, the transmitting unit  801  transmits the service information to the base station based on the modified scheduling information. 
     For example, the scheduling information transmitted by the transmitting unit  801  may include the modulation and coding information for the service information. When the transmitting unit  801  transmits the modulation and coding information for the service information, the base station receives the modulation and coding information for the service information. Then, the base station may select a preferable coding and modulation mode for the user terminal based on load conditions, channel conditions and the like in the cell, to obtain information on the preferable modulation and coding mode. Then, the base station may feed back the information on the preferable modulation and coding mode to the user terminal by including it in the response information. Accordingly, the receiving unit  802  receives the information on the preferable modulation and coding mode. Then, the transmitting unit  801  transmits the service information to the base station based on the preferable modulation and coding mode. 
     Similarly, the scheduling information transmitted by the transmitting unit  801  may include information on the number of times of retransmissions for the service information, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, or radio resource information for the service information and the like. That is, the base station may select the number of times of retransmissions, a transmission power, a signature mode, radio resources and the like that are preferable for the user terminal based on load conditions, channel conditions and the like in the cell. 
     Certainly, the base station may also select a modulation and coding mode, the number of times of retransmissions, a transmission power, a signature mode, radio resources and the like that are inferior for the user terminal based on load conditions, channel conditions and the like in the cell, which sacrifices part of the user terminal performance while realizes an overall performance improvement of the cell. 
     According to another example of this embodiment, the base station may further transmit second scheduling information to the user terminal. For example, when the transmitting unit  801  transmits the first scheduling information for the service information, the response information received by the receiving unit  802  may further include the second scheduling information. Specifically, the second scheduling information may be supplementary information of the base station to the first scheduling information. 
     For example, when the transmitting unit  801  transmits only the modulation and coding information in the scheduling information for the service information, the response information received by the receiving unit  802  may include other information in the scheduling information for the service information, such as information on the number of times of retransmissions, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, radio resource information for the service information, and the like. 
     According to another example of this embodiment, when the transmitting unit  801  transmits the first scheduling information for the service information, the response information received by the receiving unit  802  may include not only the modified first scheduling information, but also the second scheduling information. 
     For example, when the transmitting unit  801  transmits only the modulation and coding information in the scheduling information for the service information, the base station modifies the modulation and coding information after receiving it to obtain modified modulation and coding information, and thus the response information received by the receiving unit  802  may include not only other information in the scheduling information for the service information, such as information on the number of times of retransmissions, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, radio resource information for the service information and the like, but also the modified modulation and coding information. 
     The specific content of the response information received by the receiving unit  802  has been described above, and the time that the receiving unit  802  receives the response information will be described below. In this embodiment, the time that the receiving unit  802  receives the response information may be a moment or a time window. 
     According to an example of this embodiment, the transmitting unit  801  may transmit information indicating a first time interval to the base station when transmitting the access information of the user terminal. The base station may transmit the response information to the access information after the first time interval according to the received access information. For example, after receiving the access information, the base station may transmit the response information of the base station to the access information at a moment or any moment in a time window after a predetermined time interval. Accordingly, the receiving unit  802  may receive the response information of the base station to the access information at a moment or in a time window after the first time interval. 
     According to another example of this embodiment, the transmitting unit  801  may also determine a periodic information-receiving window, and receive the response information of the base station to the access information in a first information-receiving window after transmitting the access information of the user terminal. The information-receiving window may be a time window for transmitting signaling between the user terminal and the base station. Alternatively, the information-receiving window may be a time period. 
     In this example, the signaling transmitted in the time window may include user terminal-specific signaling information transmitted by the base station to the user terminal, or group-specific signaling information of a user terminal group to which the user terminal belongs. The user terminal-specific signaling may include cell reference signals, downlink control information and the like; the group-specific signaling information may include channel quality conditions, resource allocation conditions, user terminal grouping conditions, and so on. 
     The user terminal group mentioned herein may include one or more user terminals transmitting signaling information in a same time slot, or may include one or more user terminals transmitting signaling information in a same frequency band, or may be one or more user terminals that transmit access information within a time period between two adjacent information-receiving windows. 
     Furthermore, according to another example of this embodiment, the base station may transmit the response information to the access information on an existing downlink channel, or may transmit the response information to the access information on a dedicated channel. 
     Specifically, the base station may transmit the response information to the access information on a downlink control channel, a downlink data channel, or a response information transmission channel. Accordingly, the receiving unit  802  receives the response information of the base station to the access information on the corresponding downlink control channel, the downlink data channel, or the response information transmission channel. 
     For example, the downlink control channel may include a Physical Downlink Control Channel (PDCCH), a Physical Multicast Channel (PMCH), a Physical Broadcast Channel (PBCH), a Physical Control Format Indicator Channel (PCFICH), and a Physical HARQ Indicator Channel (PHICH) and the like; the downlink data channel may include a Physical Downlink Shared Channel (PDSCH) and the like; the response information transmission channel may include a channel dedicated to receive the response information. 
     According to another example of this embodiment, the receiving unit  802  may determine radio resources carrying the response information based on at least one of the identification information of the user terminal and information on radio resources for transmitting the uplink data control information, and then receive the response information of the base station to the access information on the radio resources. 
     For example, the base station determines, for user terminals in the cell, a radio resource pool for transmitting response information. After receiving access information of a certain user terminal, the base station selects radio resources for the user terminal, and then transmits response information to the access information of this user terminal on the radio resources. The receiving unit  802  may deduce index numbers of radio resources used by the base station based on the identification information of the user terminal, and then receive the response information on the radio resources corresponding to the index numbers. 
     As another example, the base station determines, for user terminals in the cell, a radio resource pool for transmitting response information. After receiving access information of a user terminal, the base station selects radio resources for the user terminal, and then transmits response information to the access information of this user terminal on the radio resources. The receiving unit  802  may deduce index numbers of radio resources used by the base station not only based on the identification information of the user terminal but also based on the information on radio resources for transmitting the uplink data control information, and then receive the response information on the radio resources corresponding to the index numbers. 
     In this example, the base station may use frequency resources for transmitting the uplink data control information as frequency resources for transmitting the response information. That is, frequency resources for transmitting the uplink data control information and frequency resources for transmitting the response information may be identical. Alternatively, the base station may also use a subframe pattern corresponding to radio resources for transmitting the uplink data control information as a subframe pattern for transmitting the response information. That is, a subframe pattern for transmitting the uplink data control information and a subframe pattern for transmitting the response information may be identical. 
     Then, after the receiving unit  802  receives the response information to the access information, the transmitting unit  801  transmits the service information, where the service information includes data information. In this embodiment, the transmitting unit  801  transmits the service information only after the receiving unit  802  receives the response information of the base station to the access information, thereby avoiding waste of radio resources. 
     According to one example of this embodiment, if the access information transmitted by the transmitting unit  801  includes a preamble code and then the receiving unit  802  receives response information of the base station to the preamble code, the transmitting unit  801  transmits the data information. 
     According to another example of this embodiment, if the access information transmitted by the transmitting unit  801  includes uplink data control information and then the receiving unit  802  receives response information of the base station to the uplink data control information, the transmitting unit  801  transmits the data information. 
     According to another example of this embodiment, if the access information transmitted by the transmitting unit  801  includes a preamble code and uplink data control information and then the receiving unit  802  receives response information of the base station to the preamble code and the uplink data control information, the transmitting unit  801  transmits the data information. 
     According to another example of this embodiment, if the access information transmitted by the transmitting unit  801  includes a preamble code and then the receiving unit  802  receives response information of the base station to the preamble code, the transmitting unit  801  transmits uplink data control information and the data information. 
     According to another example of this embodiment, if the access information transmitted by the transmitting unit  801  includes a preamble code and then the receiving unit  802  receives response information of the base station to the preamble code, the transmitting unit  801  transmits uplink data control information firstly, receives response information of the base station to the uplink data control information that includes acknowledgement information of the base station to the uplink data control information, and then transmits service information after receiving the response information of the uplink data control information. 
     The specific process of the transmitting unit  801  transmitting the service information has been described above, and the time that the transmitting unit  801  transmits the service information will be described below. 
     According to one example of this embodiment, the transmitting unit  801  may also transmit information indicating a second time interval to the base station when transmitting the access information of the user terminal. After receiving the response information, the user terminal may transmit the service information to the base station after the second time interval, so that the base station receives the service information transmitted by the user terminal at a corresponding moment. For example, after receiving the response information, the user terminal may transmit the service information at a moment or any moment in a time window after a predetermined time interval. 
     According to another example of this embodiment, the transmitting unit  801  may not transmit information indicating the second time interval to the base station. Specifically, after receiving the response information, the user terminal may transmit the service information after a third time interval. 
     As for the □first time interval□, the □second time interval□ and the □third time interval□ mentioned above, time lengths corresponding to them may be the same or different, which is not limited by this embodiment. 
     The user terminal  800  has been described in detail above, and examples of the user terminal  800  may be further described with reference to  FIGS. 2-6 , which is not repeatedly described herein. 
     According to the user terminal for information transmission in grant-free uplinks provided by the embodiments of the present disclosure, the user terminal firstly transmits the access information to the base station, and the user terminal transmits the service information only after receiving the base stations  acknowledgement information to the access information, thereby avoiding invalid transmission of the service information, and thus reducing waste of radio resources and improving uplink spectral efficiency. 
     A base station performing the method  700  shown in  FIG. 7  according to embodiments of the present disclosure will be described below with reference to  FIG. 9 .  FIG. 9  shows a schematic structural diagram of the base station  900  performing the method  700  shown in  FIG. 7 . 
     As shown in  FIG. 9 , the base station  900  includes a receiving unit  901  configured to receive access information of a user terminal. The base station  900  further includes a decoding unit  902  configured to decode the access information of the user terminal. The base station  900  further includes a transmitting unit  903  which is configured to transmit the response information after the decoding unit  902  correctly decodes the access information of the user terminal, where the response information includes acknowledgement information of the base station to the access information. In addition, the receiving unit  901  is further configured to receive service information after the transmitting unit  903  transmits the response information, where the service information includes data information. The base station  900  may further include other components in addition to these three units. However, since these components are not related to the content of the embodiments of the present disclosure, illustration and description thereof are omitted herein. Furthermore, since specific details of the following operations performed by the base station  900  according to the embodiments of the present disclosure are the same as those described above with reference to  FIGS. 2-6 , repeated descriptions of the same details are omitted herein to avoid repetition. 
     According to one example of this embodiment, the access information may include a preamble code (also referred to as a preamble sequence or a random access preamble code) and/or uplink data control information. 
     For example, the preamble code may include a cyclic prefix CP with a length of Tcp and a sequence with a length of Tseq. For a cell formed by a base station, there may be 64 preamble codes. When accessing to the base station, the user terminal selects one of the 64 preamble codes for access to prevent access collisions with other user terminals. 
     Furthermore, the preamble code may further include identification information of the user terminal. The identification information of the user terminal may be, for example, the user terminal&#39;s ID, the user terminal&#39;s physical address (also referred to as Media Access Control (MAC) address), or other information that can uniquely identify the user terminal and the like, to identify the user terminal&#39;s identity. After receiving the preamble code of the user terminal, the base station may obtain the identification information of the user terminal from the preamble code, thereby identifying the user terminal&#39;s identity. 
     As another example, the uplink data control information may include Uplink Control CHannel (ULCCH) information of the user terminal. 
     As described above, the access information received by the receiving unit  901  may include both a preamble code and uplink data control information. Alternatively, the access information received by the receiving unit  901  may also include only one of a preamble code and uplink data control information. 
     When the access information includes a preamble code and uplink data control information, both the preamble code and the uplink data control information may include the identification information of the user terminal, or one of the two may include the identification information of the user terminal, to identify the user terminal&#39;s identity. 
     Furthermore, when the access information includes only uplink data control information, the uplink data control information may include the identification information of the user terminal. As described above, the identification information of the user terminal may be, for example, the user terminal&#39;s ID, the user terminal&#39;s MAC address, or other information that can uniquely identify the user terminal and the like, to identify the user terminal&#39;s identity. After receiving the uplink data control information of the user terminal, the base station may obtain the identification information of the user terminal from the uplink data control information, thereby identifying the user terminal&#39;s identity. 
     According to another example of this embodiment, the access information received by the receiving unit  901  may further include first scheduling information for the service information. The service information will be further described later. 
     According to an example of this embodiment, the first scheduling information may include at least one of modulation and coding information for the service information, information on the number of times of retransmissions for the service information, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, and radio resource information for the service information. After receiving the first scheduling information, the base station may process the service information transmitted by the user terminal according to the first scheduling information. 
     For example, the modulation and coding information for the service information may indicate a modulation and coding mode adopted by the user terminal when transmitting the service information, so that the base station may demodulate and decode the service information according to the modulation and coding information after receiving the service information. 
     As another example, the information on the number of times of retransmissions for the service information may indicate the number of times of retransmissions after the user terminal failing to transmit the service information, so that the base station may perform hybrid feedback retransmission combination on the service information received for multiple times. 
     As yet another example, the transmission power control information for the service information may indicate a transmission power adopted by the user terminal when transmitting the service information, so that the base station may obtain the transmission power for the user terminal, and thereby perform channel measurement or channel estimation. 
     As yet another example, the signature information for the service information may indicate an interleaving mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before interleaving according to the interleaving mode after receiving the service information (this operation may also be referred to as □de-interleaving□). The signature information for the service information may also indicate a scrambling mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before scrambling according to the scrambling mode after receiving the service information (this operation may also be referred to as □de-scrambling□). The signature information for the service information may also indicate a spreading mode adopted by the user terminal when transmitting the service information, so that the base station may recover information before spreading according to the spreading mode after receiving the service information. Certainly, the signature information for the service information is not limited to the interleaving mode, the scrambling mode, and the spreading mode listed herein, and may also indicate other operations that the user terminal performs on the service information when transmitting the service information. 
     As yet another example, the reference signal information for the service information may indicate reference signals of a channel adopted by the user terminal when transmitting the service information, so that the base station may perform channel measurement or channel estimation. 
     As yet another example, the radio resource information for the service information may indicate radio resources occupied by the user terminal when transmitting the service information, so that the base station may receive the service information on the radio resources. 
     Then, the decoding unit  902  decodes the access information of the user terminal, and transmits response information if decoding correctly, where the response information includes acknowledgement information (also referred to as □ACK□) of the base station to the access information. In this embodiment, when the base station decodes the access information correctly, the base station may feed back the acknowledgement information to the user terminal. On the other hand, when the base station does not decode the access information correctly, the base station may not feed back any information to the user terminal, or may feed back non-acknowledgment information (also referred to as □NACK□) to the user terminal. 
     According to one example of this embodiment, when the access information received by the receiving unit  901  includes a preamble code, the decoding unit  902  decodes the preamble code of the user terminal, and if decoding correctly, the transmitting unit  903  transmits response information, where the response information includes acknowledgement information of the base station to the preamble code. For example, after the receiving unit  901  receives the preamble code, the decoding unit  902  decodes the preamble code, and if decoding correctly, the acknowledgement information may be fed back to the user terminal. In this example, a correct decoding may be that the base station obtains the identification information of the user terminal through the decoding and thereby identifies the user terminal&#39;s identity. 
     According to another example of this embodiment, when the access information received by the receiving unit  901  includes uplink data control information, the decoding unit  902  decodes the uplink data control information of the user terminal, and if decoding correctly, the transmitting unit  903  transmits response information, where the response information includes acknowledgement information of the base station to the uplink data control information. For example, after the receiving unit  901  receives the uplink data control information, the decoding unit  902  decodes the uplink data control information, and if decoding correctly, the transmitting unit  903  may feed back acknowledgement information to the user terminal. 
     According to another example of this embodiment, when the access information received by the receiving unit  901  includes a preamble code and uplink data control information, the decoding unit  902  decodes the preamble code and the uplink data control information of the user terminal, and if decoding correctly, the transmitting unit  903  transmits response information, where the response information includes acknowledgement information of the base station to the preamble code and the uplink data control information. For example, after the receiving unit  901  receives the preamble code and the uplink data control information, the decoding unit  902  decodes them, and if decoding correctly, the transmitting unit  903  may feed back acknowledgement information to the user terminal. 
     In this example, the acknowledgement information is fed back to the user terminal only after the decoding unit  902  correctly decodes the preamble code and the uplink data control information, respectively. 
     In addition, according to another example of this embodiment, the response information transmitted by the transmitting unit  903  may further include Timing Advance (TA) information transmitted by the base station to the user terminal. For example, the base station may transmit a timing advance command to the user terminal to inform the user terminal of the amount of time of the timing advance, thereby avoiding transmission delay caused by the distance between the base station and the user terminal, and reducing interference between the user terminal and other user terminals. 
     Furthermore, according to another example of this embodiment, when the receiving unit  901  receives the first scheduling information for the service information, the base station generates modified scheduling information according to the first scheduling information for the service information, and the transmitting unit  903  feeds back the modified scheduling information to the user terminal by including it in the response information. 
     For example, when the user terminal transmits scheduling information for the service information, the base station receives the scheduling information for the service information. Then, the base station may flexibly modify the received scheduling information based on load conditions, channel conditions and the like in the cell to obtain the modified scheduling information. The base station may then feed back the modified scheduling information to the user terminal by including it in the response information. Accordingly, the user terminal receives the modified scheduling information. Then, the user terminal may transmit the service information to the base station based on the modified scheduling information. 
     For example, the scheduling information received by the receiving unit  901  may include the modulation and coding information for the service information, and then the base station may select a preferable coding and modulation mode for the user terminal based on load conditions, channel conditions and the like in the cell, to obtain information on the preferable modulation and coding mode. Then, the transmitting unit  903  may feed back the information on the preferable modulation and coding mode to the user terminal by including it in the response information. After receiving the information on the preferable modulation and coding mode, the user terminal may transmit the service information to the base station based on the preferable modulation and coding mode. 
     Similarly, the scheduling information received by the receiving unit  901  may include information on the number of times of retransmissions for the service information, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, or radio resource information for the service information and the like. That is, the base station may select the number of times of retransmissions, a transmission power, a signature mode, radio resources and the like that are preferable for the user terminal based on load conditions, channel conditions and the like in the cell. 
     Certainly, the base station may also select a modulation and coding mode, the number of times of retransmissions, a transmission power, a signature mode, radio resources and the like that are inferior for the user terminal based on load conditions, channel conditions and the like in the cell, which sacrifices part of the user terminal performance while realizes an overall performance improvement of the cell. 
     According to another example of this embodiment, the transmitting unit  903  may further transmit second scheduling information to the user terminal. For example, when the receiving unit  901  receives the first scheduling information for the service information, the base station may generate the second scheduling information, and the response information transmitted by the transmitting unit  903  may further include the second scheduling information. Specifically, the second scheduling information may be supplementary information of the base station to the first scheduling information. 
     For example, when the receiving unit  901  receives only the modulation and coding information in the scheduling information for the service information, the response information transmitted by the transmitting unit  903  may include other information in the scheduling information for the service information, such as information on the number of times of retransmissions, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, radio resource information for the service information, and the like. 
     According to another example of this embodiment, when the receiving unit  901  receives the first scheduling information for the service information, the response information transmitted by the transmitting unit  903  may include not only the modified first scheduling information, but also the second scheduling information. 
     For example, when the receiving unit  901  receives only the modulation and coding information in the scheduling information for the service information, the base station modifies the modulation and coding information after receiving it to obtain modified modulation and coding information, and thus the response information transmitted by the transmitting unit  903  may include not only other information in the scheduling information for the service information, such as information on the number of times of retransmissions, transmission power control information for the service information, signature information for the service information, reference signal information for the service information, radio resource information for the service information and the like, but also the modified modulation and coding information. 
     The specific content of the response information transmitted by the transmitting unit  903  has been described above, and the time that the transmitting unit  903  transmits the response information will be described below. In this embodiment, the time that the transmitting unit  903  transmits the response information may be a moment or a time window. 
     According to an example of this embodiment, the receiving unit  901  may further receive information indicating a first time interval. After receiving the access information, the base station may transmit the response information to the access information after the first time interval. For example, after receiving the access information, the base station may transmit the response information of the base station to the access information at a moment or any moment in a time window after a predetermined time interval. Accordingly, the user terminal may receive the response information of the base station to the access information at a moment or in a time window after the first time interval. 
     According to another example of this embodiment, the base station may also determine a periodic information-receiving window, and transmit the response information of the base station to the access information in a first information-receiving window after the receiving unit  901  receives the access information of the user terminal. The information-receiving window may be a time window for transmitting signaling between the user terminal and the base station. Alternatively, the information-receiving window may be a time period. 
     In this example, the signaling transmitted in the time window may include user terminal-specific signaling information transmitted by the base station to the user terminal, or group-specific signaling information of a user terminal group to which the user terminal belongs. The user terminal-specific signaling may include cell reference signals, downlink control information and the like; the group-specific signaling information may include channel quality conditions, resource allocation conditions, user terminal grouping conditions, and so on. 
     The user terminal group mentioned herein may include one or more user terminals transmitting signaling information in a same time slot, or may include one or more user terminals transmitting signaling information in a same frequency band, or may be one or more user terminals that transmit access information within a time period between two adjacent information-receiving windows. 
     Furthermore, according to another example of this embodiment, the base station may transmit the response information to the access information on an existing downlink channel, or may transmit the response information to the access information on a dedicated channel. 
     Specifically, the transmitting unit  903  may transmit the response information to the access information on a downlink control channel, a downlink data channel, or a response information transmission channel. Accordingly, the user terminal receives the response information of the base station to the access information on the corresponding downlink control channel, the downlink data channel, or the response information transmission channel. 
     For example, the downlink control channel may include a Physical Downlink Control Channel (PDCCH), a Physical Multicast Channel (PMCH), a Physical Broadcast Channel (PBCH), a Physical Control Format Indicator Channel (PCFICH), and a Physical HARQ Indicator Channel (PHICH) and the like; the downlink data channel may include a Physical Downlink Shared Channel (PDSCH) and the like; the response information transmission channel may include a channel dedicated to receive the response information. 
     According to another example of this embodiment, the transmitting unit  903  may determine radio resources carrying the response information based on at least one of the identification information of the user terminal and information on radio resources for transmitting the uplink data control information, and then transmit the response information of the base station to the access information on the radio resources. 
     For example, the base station determines, for user terminals in the cell, a radio resource pool for transmitting response information. After receiving access information of a user terminal, the base station selects radio resources for the user terminal, and then transmits response information to the access information of this user terminal on the radio resources. The transmitting unit  903  may deduce index numbers of radio resources used by the base station based on the identification information of the user terminal, and then transmit the response information on the radio resources corresponding to the index numbers. 
     As another example, the base station determines, for user terminals in the cell, a radio resource pool for transmitting response information. After receiving access information of a user terminal, the base station selects radio resources for the user terminal, and then transmits response information to the access information of this user terminal on the radio resources. The transmitting unit  903  may deduce index numbers of radio resources used by the base station not only based on the identification information of the user terminal but also based on the information on radio resources for transmitting the uplink data control information, and then transmit the response information on the radio resources corresponding to the index numbers. 
     In this example, the base station may use frequency resources for transmitting the uplink data control information as frequency resources for transmitting the response information. That is, frequency resources for transmitting the uplink data control information and frequency resources for transmitting the response information may be identical. Alternatively, the base station may also use a pattern corresponding to radio resources for transmitting the uplink data control information as a subframe pattern for transmitting the response information. That is, a subframe pattern for transmitting the uplink data control information and a subframe pattern for transmitting the response information may be identical. 
     In addition, according to another example of this embodiment, the transmitting unit  903  may transmit response information to each user terminal separately, and alternatively, the base station may also transmit response information of a group of user terminals at the same time. The □group of user terminals□ herein may be the □user terminal group□ described above. 
     Then, after the transmitting unit  903  transmits the response information, the receiving unit  901  receives service information, where the service information includes data information. In this embodiment, the user terminal transmits the service information only after receiving the response information of the base station to the access information, thereby avoiding waste of radio resources. Accordingly, the receiving unit  901  receives the service information only after the transmitting unit  903  transmits the response information. 
     According to an example of this embodiment, if the access information received by the receiving unit  901  includes a preamble code and then the transmitting unit  903  transmits response information of the base station to the preamble code, the receiving unit  901  may receive the data information. 
     According to another example of this embodiment, if the access information received by the receiving unit  901  includes uplink data control information and then the transmitting unit  903  transmits response information of the base station to the uplink data control information in step S 702 , the receiving unit  901  may receive the data information. 
     According to another example of this embodiment, if the access information received by the receiving unit  901  includes a preamble code and uplink data control information and then the transmitting unit  903  transmits response information of the base station to the preamble code and the uplink data control information, the receiving unit  901  may receive the data information. 
     According to another example of this embodiment, if the access information received by the receiving unit  901  includes a preamble code and then the transmitting unit  903  transmits response information of the base station to the preamble code, the receiving unit  901  may also receive uplink data control information and the data information. 
     According to another example of this embodiment, if the access information received by the receiving unit  901  includes a preamble code and then the transmitting unit  903  transmits response information of the base station to the preamble code, the receiving unit  901  may also receive uplink data control information firstly, transmit response information to the uplink data control information that includes acknowledgement information of the base station to the uplink data control information, and then receive service information after the transmitting unit  903  transmits the response information of the uplink data control information. 
     In addition, according to an example of this embodiment, the receiving unit  901  may also receive information indicating a second time interval when receiving the access information of the user terminal. After receiving the response information, the user terminal may transmit the service information to the base station after the second time interval, so that the base station receives the service information transmitted by the user terminal at a corresponding moment. For example, after receiving the response information, the user terminal may transmit the service information at a moment or any moment in a time window after a predetermined time interval. 
     As for the □first time interval□ and the □second time interval□ mentioned above, time lengths corresponding to them may be the same or different, which is not limited by this embodiment. 
     The base station  900  has been described in detail above, and examples of the base station  900  may be further described with reference to  FIGS. 2-6 , which will not be repeatedly described herein. 
     According to the base station for information transmission of grant-free uplinks provided by the embodiments of the present disclosure, the user terminal first transmits the access information to the base station, and the user terminal transmits the service information only after receiving the base station acknowledgement information to the access information, thereby avoiding invalid transmission of the service information, and thus reducing waste of radio resources and improving uplink spectral efficiency. 
     In addition, block diagrams used in the description of the above embodiments illustrate blocks in units. These structural blocks may be implemented in arbitrary combination of hardware and/or software. Furthermore, means for implementing respective structural blocks is not particularly limited. That is, the respective structural blocks may be implemented by one apparatus that is physically and/or logically jointed; or more than two apparatuses that are physically and/or logically separated may be directly and/or indirectly connected (e.g., in a wire and/or wireless mode), and the respective structural blocks may be implemented by these apparatuses. 
     For example, the user equipment in the embodiments of the present disclosure may function as a computer that executes the processes of the information transmission method of the present disclosure.  FIG. 10  shows a schematic diagram of hardware structure of a user equipment  1000  related according to an embodiment of the present disclosure. The above user equipment  1000  may be constituted as a computer apparatus that physically comprises a processor  1010 , a memory  1020 , a storage  1030 , a communication apparatus  1040 , an input apparatus  1050 , an output apparatus  1060 , a bus  1070  and the like 
     In addition, in the following description, terms such as □apparatus□ may be replaced with circuits, devices, units, and the like. The hardware structure of the user equipment  1000  may include one or more of the respective apparatuses shown in the figure, or may not include a part of the apparatuses. 
     For example, only one processor  1010  is illustrated, but there may be multiple processors. Furthermore, processes may be performed by one processor, or processes may be performed by more than one processor simultaneously, sequentially, or by other methods. In addition, the processor  1010  may be installed by more than one chip. 
     Respective functions of the user equipment  1000  may be implemented, for example, by reading specified software (program) on hardware such as the processor  1010  and the memory  1020 , so that the processor  1010  performs computations, controls communication performed by the communication apparatus  1040 , and controls reading and/or writing of data in the memory  1020  and the storage  1030 . 
     The processor  1010 , for example, operates an operating system to control the entire computer. The processor  1010  may be constituted by a Central Processing Unit (CPU), which includes interfaces with peripheral apparatuses, a control apparatus, a computing apparatus, a register and the like. For example, the baseband signal processing unit, the call processing unit and the like described above may be implemented by the processor  1010 . 
     In addition, the processor  1010  reads programs (program codes), software modules and data from the storage  1030  and/or the communication apparatus  1040  to the memory  1020 , and execute various processes according to them. As for the program, a program causing computers to execute at least a part of the operations described in the above embodiments may be employed. For example, a control unit of the user equipment  1000  may be implemented by a control program stored in the memory  1020  and operated by the processor  1010 , and other functional blocks may also be implemented similarly. 
     The memory  1020  is a computer-readable recording medium, and may be constituted, for example, by at least one of a Read Only Memory (ROM), an Erasable Programmable ROM (EPROM), an Electrically EPROM (EEPROM), a Random Access Memory (RAM) and other appropriate storage media. The memory  1020  may also be referred to as a register, a cache, a main memory (a main storage apparatus) and the like. The memory  1020  may store executable programs (program codes), software modules or the like for implementing wireless communication methods related to an embodiment of the present disclosure. 
     The storage  1030  is a computer-readable recording medium, and may be constituted, for example, by at least one of a flexible disk, a Floppy® disk, a magneto-optical disk (e.g., a Compact Disc ROM (CD-ROM) and the like), a digital versatile disk, a Blu-ray® disk, a removable disk, a hard driver, a smart card, a flash memory device (e.g., a card, a stick and a key driver), a magnetic stripe, a database, a server, and other appropriate storage media. The storage  1030  may also be referred to as an auxiliary storage apparatus. 
     The communication apparatus  1040  is a hardware (transceiver device) performing communication between computers via a wired and/or wireless network, and is also referred to as a network device, a network controller, a network card, a communication module or the like, for example. The communication device  1040  may include a high-frequency switch, a duplexer, a filter, a frequency synthesizer and the like to implement, for example, Frequency Division Duplex (FDD) and/or Time Division Duplex (TDD). For example, the transmitting and receiving antennas, amplifying unit, transmitting and receiving units, transmission path interfaces and the like described above may be implemented by the communication apparatus  1040 . 
     The input apparatus  1050  is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor and the like) that receives input from the outside. The output apparatus  1060  is an output device (e.g., a display, a speaker, a Light Emitting Diode (LED) light and the like) that performs outputting to the outside. In addition, the input apparatus  1050  and the output apparatus  1060  may also be an integrated structure (e.g., a touch screen). 
     Furthermore, the respective apparatuses such as the processor  1010  and the memory  1020  are connected by the bus  1070  that communicates information. The bus  1070  may be constituted by a single bus or by different buses between the apparatuses. 
     Furthermore, the user equipment  1000  may comprise hardware such as a microprocessor, a Digital Signal Processor (DSP), an Application Specified Integrated Circuit (ASIC), a Programmable Logic Device (PLD), a Field Programmable Gate Array (FPGA), etc., and the hardware may be used to implement a part of or all of the respective functional blocks. For example, the processor  1010  may be installed by at least one of the hardware. 
     The terms illustrated in the present specification and/or the terms required for understanding of the present specification may be substituted with terms having the same or similar meaning. For example, a channel and/or a symbol may also be a signal (signaling). Furthermore, the signal may be a message. A reference signal may be abbreviated as an CRS and may also be referred to as a □pilot□, a □pilot signal□ and so on, depending on the standard applied. Furthermore, a component carrier (CC) may also be referred to as a cell, a frequency carrier, a carrier frequency, and the like. 
     In addition, a radio frame may be composed of one or more periods (frames) in the time domain. Each of the one or more periods (frames) constituting the radio frame may also be referred to as a subframe. Further, a subframe may be composed of one or more slots in the time domain. The subframe may be a fixed length of time duration (e.g., 1 ms) that is independent of the numerology. 
     Furthermore, a slot may be composed of one or more symbols (OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, etc.) in the time domain. Furthermore, the slot may also be a time unit based on the numerology. Furthermore, the slot may also include a plurality of microslots. Each microslot may be composed of one or more symbols in the time domain. Furthermore, a microslot may also be referred to as a □subframe□. 
     A radio frame, a subframe, a slot, a microslot and a symbol all represent a time unit during signal transmission. A radio frame, a subframe, a slot, a microslot and a symbol may also use other names that correspond to thereof, respectively. For example, one subframe may be referred to as a □transmission time interval (TTI)□, and a plurality of consecutive subframes may also be referred to as a □TTI□, and one slot or one microslot may also be referred to as a □TTI.□ That is, a subframe and/or a TTI may be a subframe (1 ms) in the existing LTE, may be a period of time shorter than 1 ms (e.g., 1 to 13 symbols), or may be a period of time longer than 1 ms. In addition, a unit indicating a TTI may also be referred to as a slot, a microslot and the like instead of a subframe. 
     Herein, a TTI refers to the minimum time unit of scheduling in wireless communication, for example. For example, in LTE systems, a wireless base station performs scheduling for respective user terminals that allocates radio resources (such as frequency bandwidths and transmission power that can be used in respective user terminals) in units of TTI. In addition, the definition of the TTI is not limited thereto. 
     The TTI may be a transmission time unit of channel-coded data packets (transport blocks), code blocks, and/or codewords, or may be a processing unit of scheduling, link adaptation and so on. In addition, when the TTI is given, a time interval (e.g., the number of symbols) mapped to transport blocks, code blocks, and/or codewords actually may also be shorter than the TTI. 
     In addition, when one slot or one microslot is called a TTI, more than one TTI (i.e., more than one slot or more than one microslot) may also become the minimum time unit of scheduling. Furthermore, the number of slots (the number of microslots) constituting the minimum time unit of the scheduling may be controlled. 
     A TTI having a time duration of 1 ms may also be referred to as a normal TTI (TTI in LTE Rel. 8-12), a standard TTI, a long TTI, a normal subframe, a standard subframe, or a long subframe, and so on. A TTI that is shorter than a normal TTI may also be referred to as a compressed TTI, a short TTI, a partial (or fractional) TTI, a compressed subframe, a short subframe, a microslot, a subslot, and so on. 
     In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may also be replaced with a TTI having a time duration exceeding 1 ms, and a short TTI (e.g., a compressed TTI, etc.) may also be replaced with a TTI having a TTI duration shorter than the long TTI and longer than 1 ms. 
     A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. Also, an RB may include one or more symbols in the time domain, and may be one slot, one microslot, one subframe or one TTI duration. One TTI and one subframe may be composed of one or more resource blocks, respectively. In addition, one or more RBs may also be referred to as □physical resource blocks (PRBs (Physical RBs))□, □Sub-Carrier Groups (SCGs)□, □Resource Element Groups (REGs)□, □PRG pairs□, □RB pairs□ and so on. 
     Furthermore, a resource block may also be composed of one or more resource elements (REs). For example, one RE may be a radio resource area of one subcarrier and one symbol. 
     In addition, structures of the radio frames, subframes, slots, microslots and symbols, etc. described above are simply examples. For example, configurations such as the number of subframes included in a radio frame, the number of slots of each subframe or radio frame, the number or microslots included in a slot, the number of symbols and RBs included in a slot or microslot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol duration and the cyclic prefix (CP) duration may be variously altered. 
     Furthermore, the information, parameters and so on described in this specification may be represented in absolute values or in relative values with respect to specified values, or may be represented by other corresponding information. For example, radio resources may be indicated by specified indices. Furthermore, equations and the like using these parameters may be different from those explicitly disclosed in this specification. 
     The names used for the parameters and the like in this specification are not limited in any respect. For example, since various channels (PUCCHs (Physical Uplink Control Channels), PDCCHs (Physical Downlink Control Channels), etc.) and information elements may be identified by any suitable names, the various names assigned to these various channels and information elements are not limited in any respect. 
     The information, signals and the like described in this specification may be represented by using any one of various different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. possibly referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or photons, or any combination thereof. 
     In addition, information, signals and the like may be output from higher layers to lower layers and/or from lower layers to higher layers. Information, signals and the like may be input or output via a plurality of network nodes. 
     The information, signals and the like that are input or output may be stored in a specific location (for example, in a memory), or may be managed in a control table. The information, signals and the like that are input or output may be overwritten, updated or appended. The information, signals and the like that are output may be deleted. The information, signals and the like that are input may be transmitted to other apparatuses. 
     Reporting of information is by no means limited to the aspects/embodiments described in this specification, and may be implemented by other methods as well. For example, reporting of information may be implemented by using physical layer signaling (for example, downlink control information (DCI), uplink control information (UCI)), higher layer signaling (for example, RRC (Radio Resource Control) signaling, broadcast information (master information blocks (MIBs), system information blocks (SIBs), etc.), MAC (Medium Access Control) signaling), other signals or combinations thereof. 
     In addition, physical layer signaling may also be referred to as L1/L2 (Layer 1/Layer 2) control information (L1/L2 control signals), L1 control information (L1 control signal) and the like. Furthermore, RRC signaling may also be referred to as □RRC messages□, for example, RRC connection setup messages, RRC connection reconfiguration messages, and so on. Furthermore, MAC signaling may be reported by using, for example, MAC control elements (MAC CEs). 
     Furthermore, notification of prescribed information (for example, notification of □being X□) is not limited to being performed explicitly, and may be performed implicitly (for example, by not performing notification of the prescribed information or by notification of other information). 
     Decision may be performed by a value (0 or 1) represented by 1 bit, or by a true or false value (boolean value) represented by TRUE or FALSE, or by a numerical comparison (e.g., comparison with a prescribed value). 
     Software, whether referred to as □software□, □firmware□, □middleware□, □microcode□ or □hardware description language□, or called by other names, should be interpreted broadly to mean instructions, instruction sets, code, code segments, program codes, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions and so on. 
     In addition, software, commands, information, etc. may be transmitted and received via a transport medium. For example, when software is transmitted from web pages, servers or other remote sources using wired technologies (coaxial cables, fibers, twisted pairs, Digital Subscriber Lines (DSLs), etc.) and/or wireless technologies (infrared ray, microwave, etc.), these wired technologies and/or wireless technologies are included in the definition of the transport medium. 
     The terms □system□ and □network□ used in this specification are used interchangeably. 
     In this specification, terms like □Base Station (BS)□, □wireless base station□, □eNB□, □gNB□, □cell□, □sector□, □cell group□, □carrier□ and □component carrier□ may be used interchangeably. The base station is sometimes referred to as terms such as a fixed station, a NodeB, an eNodeB (eNB), an access point, a transmitting point, a receiving point, a femto cell, a small cell, etc. 
     A base station is capable of accommodating one or more (for example, three) cells (also referred to as sectors). In a case where the base station accommodates a plurality of cells, the entire coverage area of the base station may be divided into a plurality of smaller areas, and each smaller area may provide communication services by using a base station sub-system (for example, a small base station for indoor use (a Remote Radio Head (RRH)). Terms like □cell□ and □sector□ prefer to a part of or an entirety of the coverage area of a base station and/or a sub-system of the base station that provides communication services in this coverage. 
     In this specification, terms such as □Mobile Station (MS)□, □user terminal□, □User Equipment (UE)□, and □terminal□ may be used interchangeably. The mobile station is sometimes referred by those skilled in the art as a user station, a mobile unit, a user unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile user station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other appropriate terms. 
     Furthermore, the wireless base station in this specification may also be replaced with a user terminal. For example, for a structure in which communication between a wireless base station and a user terminal is replaced with communication between a plurality of user terminals (Device-to-Device, D2D), respective manners/embodiments of the present disclosure may be applied. At this time, functions provided by the wireless base station described above may be regarded as functions provided by the user terminals. Furthermore, the words □uplink□ and □downlink□ may also be replaced with □side□. For example, an uplink channel may be replaced with a side channel. 
     Also, the user terminal in this specification may be replaced with a wireless base station. At this time, functions provided by the above user terminal may be regarded as functions provided by the wireless base station. 
     In this specification, specific actions configured to be performed by the base station sometimes may be performed by its upper nodes in certain cases. Obviously, in a network composed of one or more network nodes having base stations, various actions performed for communication with terminals may be performed by the base stations, one or more network nodes other than the base stations (for example, Mobility Management Entities (MMEs), Serving-Gateways (S-GWs), etc., may be considered, but not limited thereto)), or combinations thereof. 
     The respective manners/embodiments described in this specification may be used individually or in combinations, and may also be switched and used during execution. In addition, orders of processes, sequences, flow charts and so on of the respective manners/embodiments described in this specification may be re-ordered as long as there is no inconsistency. For example, although various methods have been described in this specification with various units of steps in exemplary orders, the specific orders as described are by no means limitative. 
     The manners/embodiments described in this specification may be applied to systems that utilize LTE (Long Term Evolution), LTE-A (LTE-Advanced), LTE-B (LTE-Beyond), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), New-RAT (New Radio Access Technology), NR (New Radio), NX (New radio access), FX (Future generation radio access), GSM® (Global System for Mobile communications), CDMA 2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi®), IEEE 802.16 (WiMAX®), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth® and other appropriate wireless communication methods, and/or next-generation systems that are enhanced based on them. 
     Terms such as □based on□ as used in this specification do not mean □based on only□, unless otherwise specified in other paragraphs. In other words, terms such as □based on□ mean both □based on only□ and □at least based on.□ 
     Any reference to units with designations such as □first□, □second□ and so on as used in this specification does not generally limit the quantity or order of these units. These designations may be used in this specification as a convenient method for distinguishing between two or more units. Therefore, reference to a first unit and a second unit does not imply that only two units may be employed, or that the first unit must precedes the second unit in several ways. 
     Terms such as □deciding (determining)□ as used in this specification may encompass a wide variety of actions. The □deciding (determining)□ may regard, for example, calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or other data structures), ascertaining, etc. as performing the □deciding (determining)□. In addition, the □deciding (determining)□ may also regard receiving (e.g., receiving information), transmitting (e.g., transmitting information), inputting, outputting accessing (e.g., accessing data in a memory), etc. as performing the □deciding (determining)□. In addition, the □deciding (determining)□ may further regard resolving, selecting, choosing, establishing, comparing, etc. as performing the □deciding (determining)□. That is to say, the □deciding (determining)□ may regard certain actions as performing the □deciding (determining)□. 
     As used herein, terms such as □connected□, □coupled□, or any variation thereof mean any direct or indirect connection or coupling between two or more units, and may include the presence of one or more intermediate units between two units that are □connected□ or □coupled□ to each other. Coupling or connection between the units may be physical, logical or a combination thereof. For example, □connection□ may be replaced with □access.□ As used in this specification, two units may be considered as being □connected□ or □coupled□ to each other by using one or more electrical wires, cables and/or printed electrical connections, and, as a number of non-limiting and non-inclusive examples, by using electromagnetic energy having wavelengths in the radio frequency region, microwave region and/or optical (both visible and invisible) region. 
     When terms such as □including□, □comprising□ and variations thereof are used in this specification or the claims, these terms, similar to the term □having□, are also intended to be inclusive. Furthermore, the term □or□ as used in this specification or the claims is not an exclusive or. 
     Although the present disclosure has been described in detail above, it should be obvious to a person skilled in the art that the present disclosure is by no means limited to the embodiments described in this specification. The present disclosure may be implemented with various modifications and alterations without departing from the spirit and scope of the present disclosure defined by the recitations of the claims. Consequently, the description in this specification is for the purpose of illustration, and does not have any limitative meaning to the present disclosure.