Patent Publication Number: US-2023133527-A1

Title: Configuration of transport block size

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national phase entry of International Application No. PCT/CN2018/083240, filed Apr. 16, 2018, the entire contents of both of which are incorporated herein by reference. 
    
    
     FIELD 
     Embodiments of the present disclosure generally relate to the field of communications, and in particular, to methods, devices and computer readable storage medium for transport block size (TBS) configuration. 
     BACKGROUND 
     In the 3rd Generation Partnership Project (3GPP) specifications, Early Data Transmission (EDT) has been proposed for enhanced machine-type communication (eMTC) and Narrowband Internet of Things (NB-IoT). In uplink (UL), the EDT allows data to be transmitted on Message 3 (Msg3) during a random access procedure. For example, user equipment (UE) may use a reserved preamble to indicate to an evolved NodeB (eNodeB or eNB) that the UE intends to perform the EDT, and then the eNB will allocate Msg3 resources for the EDT. With the EDT, interactions between the UE and the eNB may be significantly decreased, and therefore the latency and overhead of the UL data transmission may be reduced. 
     One concern on the EDT is that the eNB is unaware of the amount of data to be transmitted by the UE. Thus, if the eNB allocates a TBS that is too large, the UE has to pad a transport block (TB) with a lot of bits. For example, if the eNB allocates a TB of 1000 bits but UE only has 504 bits of data to transmit, the UE would have to pad the transport block with 496 bits. This may result in a lot of resource waste. 
     To mitigate the resource waste due to the padding, it is agreed to allow the UE to autonomously select an appropriate TBS, Modulation and Coding Scheme (MSC), Resource Unit (RU), number of repetitions or an appropriate combination of those transmission related parameters based on the amount of UL data to be transmitted. For example, the UE may choose an appropriate TBS from a set of TBSs based on the UL data and may also determine the appropriate MCS, repetitions and RUs (for Narrowband Internet of Things (NB-IoT) technology). 
     In the 3GPP standardization, how to provide the set of possible TB sizes, MCS, repetitions and RUs (for NB-IoT) are being discussed for hardcoding in the 3GPP specifications. One proposal assumes 8 possible candidate values for the maximum TBS which are broadcasted in system information. For each candidate value of the maximum TB size, up to 4 possible TBSs are allowed, which means 4 possible blind decoding options at the eNB. In this case, if the eNB indicates the maximum TBS, the UE may choose a TBS from the four possible TB sizes for the maximum TBS. 
     SUMMARY 
     In general, example embodiments of the present disclosure provide methods, devices and computer readable storage medium for TBS configuration. 
     In a first aspect, a method at a terminal device is provided. The terminal device transmits a random access preamble to a network device. The terminal device receives a random access response from the network device. The random access response includes a resource allocated for a reference TBS. Based on the reference TBS, the terminal device determines a TBS for transmitting data to the network device. Then, the terminal device transmits the data to the network device by using the determined TBS and the allocated resource. 
     In a second aspect, a method at a network device is provided. The network device receives a random access preamble from a terminal device. The network device transmits a random access response to the terminal device, the random access response including a resource allocated for a reference TBS for data transmission of the terminal device. The network device detects data from the terminal device in the allocated resource. 
     In a third aspect, there is provided a device comprising at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the device to perform the method according to the first or second aspect. 
     In a fourth aspect, there is provided a computer readable storage medium that stores a computer program thereon. The computer program, when executed by a processor, causes the processor to perform the method according to the first or second aspect. 
     It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Some example embodiments will now be described with reference to the accompanying drawings, where: 
         FIG.  1    illustrates an example communication network in which embodiments of the present disclosure can be implemented; 
         FIG.  2    illustrates an example message flow between the terminal device and the network device according to some embodiments of the present disclosure; 
         FIG.  3 ( a )  illustrates example processing for blind decoding attempts with different numbers of repetitions according to some embodiments of the present disclosure; 
         FIG.  3 ( b )  illustrates example processing for blind decoding attempts with different numbers of resource elements (REs)/physical resource blocks (PRBs) according to some embodiments of the present disclosure; 
         FIG.  3 ( c )  illustrates example processing for blind decoding attempts with different numbers of resource units (RUs) according to some embodiments of the present disclosure; 
         FIG.  4    illustrates a flowchart of an example method in accordance with some embodiments of the present disclosure; 
         FIG.  5    illustrates a flowchart of an example method in accordance with some other embodiments of the present disclosure; and 
         FIG.  6    illustrates a simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure. 
     
    
    
     Throughout the drawings, the same or similar reference numerals represent the same or similar element. 
     DETAILED DESCRIPTION 
     Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below. 
     In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs. 
     As used herein, the term “communication network” refers to a network that follows any suitable communication standards or protocols such as long term evolution (LTE), LTE-Advanced (LTE-A) and 5G NR, and employs any suitable communication technologies, including, for example, Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM), time division multiplexing (TDM), frequency division multiplexing (FDM), code division multiplexing (CDM), Bluetooth, ZigBee, machine type communication (MTC), enhanced mobile broadband (eMBB), massive machine type communication (mMTC), ultra reliable low latency communication (uRLLC) and EDT technologies. For the purpose of discussion, some embodiments are discussed in the scenario where the EDT technology is utilized. 
     As used herein, the term “network device” refers to any suitable device at a network side of a communication network. The network device may include any suitable device in an access network of the communication network, for example, including a base station (BS), a relay, an access point (AP), a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a gigabit NodeB (gNB), a Remote Radio Module (RRU), a radio header (RH), a remote radio head (RRH), a low power node such as a femto, a pico, and the like. For the purpose of discussion, in some embodiments, the eNB is taken as an example of the network device. 
     As used herein, the term “terminal device” refers to a device capable of, configured for, arranged for, and/or operable for communications with a network device or a further terminal device in a communication network. The communications may involve transmitting and/or receiving wireless signals using electromagnetic signals, radio waves, infrared signals, and/or other types of signals suitable for conveying information over air. In some embodiments, the terminal device may be configured to transmit and/or receive information without direct human interaction. For example, the terminal device may transmit information to the network device on predetermined schedules, when triggered by an internal or external event, or in response to requests from the network side. 
     Examples of the terminal device include, but are not limited to, user equipment (UE) such as smart phones, wireless-enabled tablet computers, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), and/or wireless customer-premises equipment (CPE). For the purpose of discussion, in the following, some embodiments will be described with reference to UEs as examples of the terminal devices, and the terms “terminal device” and “user equipment” (UE) may be used interchangeably in the context of the present disclosure. 
     As used herein, the term “circuitry” may refer to one or more or all of the following: 
     (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and
 
(b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and
 
(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.
 
     This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device. 
     As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term “includes” and its variants are to be read as open terms that mean “includes, but is not limited to”. The term “based on” is to be read as “based at least in part on”. The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment”. The term “another embodiment” is to be read as “at least one other embodiment”. Other definitions, explicit and implicit, may be included below. 
     As described above, in order to improve the resource efficiency, for the EDT, the UE is allowed to autonomously select an appropriate TBS/MCS/RU/repetitions based on the UL data to be transmitted. For instance, if the eNB indicates the maximum TBS of 1000 bits but the UE only has 504 bits of data to be transmit, the UE may choose the TBS of 504 bits instead of the indicated maximum TBS. 
     However, the eNB is unaware of the TBS selected by the UE. Thus, the processing of the eNB for blind decoding may become very complicated. If 4 possible TBSs are allowed for a candidate value of the maximum TBS, the eNB may have to perform up to 4 blind decoding attempts on each Physical Uplink Shared Channel (PUSCH) transmission. This may considerably increase complexity of receiver processing at the eNB. 
     For the NB-IoT, a resource usage indicator may be defined, for example, 2-bit indicator using Narrow-band Physical Uplink Shared Channel (NPUSCH) Format 2, to explicitly notify the eNB of the selected TBS prior to NPUSCH transmission. However, such explicit notification may not be allowed in the random access (RA) procedure for the EDT. 
     One conventional approach for the EDT provides fallback to a legacy Random Access Channel (RACH) procedure. For example, if the TBS indicated by the EDT UL grant is significantly greater than the UL data packet, the UE may fall back to the legacy RACH procedure and only transmit legacy Msg3. In this case, the EDT cannot be performed. 
     Another conventional approach for the EDT allows the eNB to allocate simultaneously multiple grants. For example, the eNB may allocate the grants for 328, 680 and 1000 bits of data, and further the UE may select the grant that best fits UL data buffer. This, however, increases random access response (RAR) overhead significantly and will require multiple blind decoding attempts by the eNB. 
     Embodiments of the present disclosure provide a flexible TBS configuration. After a terminal device transmits a random access request (for example, a RA preamble) to a network device, the network device returns a RAR including a resource allocated for a reference TBS. The reference TBS may be either the maximum TBS configured in system information such as system information block (SIB), or the TBS given in the RAR. The terminal device determines a TBS for UL data transmission based on the reference TBS and then transmits data to the network device by using the determined TBS and the allocated resource. 
     The reference TBS included in the RAR may be more adapted to the immediate UL data transmission, in particular, compared with the maximum TBS broadcast. Such TBS configuration is more flexible. Accordingly, the resource waste may be mitigated and the power efficiency may be increased. 
       FIG.  1    illustrates an example communication network  100  in which embodiments of the present disclosure can be implemented. The network  100  comprises a terminal device  110  and a network device  120 . It is to be understood that the numbers of network devices and terminal devices are shown only for the purpose of illustration without suggesting any limitation. The network  100  may include any suitable numbers of network devices and terminal devices. 
     The terminal device  110  may communicate with the network device  120  or with a further terminal device (not shown) via the network device  120 . The communication may utilize any suitable technology that already exists or will be developed in the future. In some embodiments, the terminal device  110  may be implemented by an eMTC or NB-IoT UE which communicates with the network device  120  using the EDT technology. 
     In various embodiments of the present disclosure, during the RA procedure, the terminal device  110  receives from the network device  120  an RAR that includes a resource allocated for a reference TBS. The terminal device  110  may autonomously determine a TBS for uplink data transmission based on the reference TBS, and then transmit the data by using the determined TBS and the allocated resource. The detailed operations and acts of the terminal device  110  and the network device  120  will be described with reference to  FIG.  2   . 
       FIG.  2    illustrates an example message flow  200  between the terminal device and the network device according to some embodiments of the present disclosure. The message flow  200  can be implemented between the terminal device  110  and the network device  120  as shown in  FIG.  1   . For the purpose of discussion, the message flow  200  will be described with reference to  FIG.  1   . 
     As shown in  FIG.  2   , the terminal device  110  transmits ( 210 ) a RA request to the network device  120 . In this example, the RA request is carried on Message 1 (Msg1). The terminal device  110  may first obtain the resource for the RA request in any suitable way. For example, the network device  120  may reserve some resources for RA requests from served terminal devices. The terminal device  110  may select its own Physical Random Access Channel (PRACH) resource from the reserved resources, for example, based on a coverage enhancement (CE) level that is used. 
     The RA request may be implemented in any suitable form. For example, the RA request may be implemented by a RA preamble. In some embodiments, a specific or reserved preamble for indicating the EDT to be performed may be used. 
     As a response to the RA request transmitted ( 210 ), the terminal device  110  receives ( 220 ) a RAR from the network device  120 , for example, on message  2  (Msg2). The RAR includes a reference TBS indication and a radio resource that is allocated for the reference TBS (i.e., the UL grant). In the method flow  200 , both the reference TBS and the allocated resource are received in RAR UL grant on Physical Downlink Shared Channel (PDSCH). As an alternative example, the reference TBS may be received in downlink control information (DCI) while the allocated resource is received in the RAR UL grant, which is also part of the DCI. 
     The reference TBS may be configured by the network device  120  to be more adapted to the immediate UL transmission in order to improve the resource efficiency. For example, the reference TBS may be smaller than a maximum TBS broadcast by the network device  120  in system information. In this example, the network device  120  may broadcast one or more maximum TBSs in the system information (for example, system information block, or SIB). The maximum TBSs may be associated with different CE levels. Accordingly, as shown, the terminal device  110  may detect ( 208 ) a maximum TBS broadcast by the network device  120  in the SIB before transmitting ( 210 ) the RA request. 
     In this case, the network device may override the maximum TBS by the reference TBS included in the RAR. For example, if the maximum TBS is configured to be 1000 bits, the network device  120  may override the maximum TBS by the reference TBS of 504 bits in the DCI. 
     It is possible that the reference TBS is equal to the maximum TBS. The RAR may not include the reference TBS. The maximum TBS broadcast in the SIB acts as the reference TBS. 
     In various embodiments of the present disclosure, the resource for the following UL transmission is allocated or configured by the network device  120  based on the reference TBS. The resource may include the number of subcarriers/physical resource blocks (PRBs), the number of repetitions, the number of resource units (RUs), and the like. 
     Based on the reference TBS received ( 220 ), the terminal device  110  determines ( 230 ) a TBS for transmitting data to the network device  120 . For example, the terminal device  110  may determine that the reference TBS is to be used for data transmission. 
     In order to further improve the flexibility of the TBS configuration, in some embodiments, the terminal device  110  may adjust the reference TBS based on the amount of the data. If the data in the UL buffer is less than the data accommodated by the reference TBS, the UE may determine a smaller TBS for transmitting the data. For example, if the reference TBS is 712 bits and the terminal device  110  has 408 bits of data to transmit, the terminal device  110  may determine a smaller TBS of 408 bits for data transmission. It is possible that the terminal device  110  may determine a larger TBS when the data is more than the reference TBS. 
     In some embodiments, a set of candidate TBSs may be defined for a reference TBS for the terminal device  110  to select. Table 1 shows example sets of candidate TBSs for different reference TBSs. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Reference TBS (bits) 
                 Candidate TBSs (bits) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 328 
                 328 
               
               
                 408 
                 408, 328 
               
               
                 504 
                 504, 408, 328 
               
               
                 600 
                 600, 504, 408, 328 
               
               
                 712 
                 712, 600, 504, 328 
               
               
                 808 
                 808, 600, 408, 328 
               
               
                 936 
                 936, 712, 504, 328 
               
               
                 1000 
                 1000, 712, 504, 328 
               
               
                   
               
            
           
         
       
     
     The terminal device  110  may select a TBS from the set of candidate TBSs based on the amount of the data to be transmitted. For example, in the case that the reference TBS is 712 bits and the data to transmit is 408 bits, the terminal device  110  may select the candidate TBS of 504 bits for data transmission. The remaining 96 bits in a TB may be padded by the terminal device  110 . 
     The above TBS adjustment may be enabled or disabled by the network device  120 . As shown, the terminal device  110  may receive ( 206 ) an indication that the TBS adjustment is enabled by the network device  120 . This indication may be broadcast by the network  120  in system information such as the SIB. Upon the reception of this indication, the terminal device  110  determines the amount of the data to be transmitted and then adjusts the reference TBS based on the amount of the data. 
     In some embodiments, the terminal device  110  may transmit, to the network device  120 , an indication that the TBS selection is enabled by the terminal device  110 . For example, the terminal device  110  may use a reserved bit in the RA preamble to indicate that the terminal device  110  is capable of autonomous TBS selection. Then, the terminal device  110  may choose whether to perform the TBS selection according to actual needs. Based on this indication, the network device  120  may detect the data based on the candidate TBSs to further reduce the receiver processing complexity. 
     After the TBS is determined ( 230 ), the terminal device  110  transmits ( 240 ) the data to the network device  120  by using the determined TBS and the allocated resource. In order to further improve the flexibility of the resource configuration, the terminal device  110  may autonomously determine from the allocated resource a resource for the UL data transmission, and then transmit the data in the determined resource. The determined resource may or may not be the same as the allocated resource. 
     Similar to the TBS adjustment, the resource adjustment by the terminal device  110  may also be enabled or disabled by the network device  120 . For example, when the indication for the TBS adjustment is received ( 206 ), the terminal device  110  may also receive an indication that the resource adjustment is enabled by the network device  120 . 
     In order to further improve the resource usage and power efficiency, in some embodiments, the terminal device  110  may adjust the allocated resource based on the determined TBS and the reference TBS. Similar to the TBS adjustment, the resource adjustment (for example, adjusting the number of repetitions, time-frequency resource, or transmission power) may also be enabled or disabled by the network device  120 . For example, when the first indication of the TBS adjustment is received ( 206 ), the terminal device  110  may also receive an indication that the resource adjustment is enabled by the network device  120 . 
     The terminal device  110  may utilize any suitable resource adjustment techniques. In the embodiments where the allocated resource includes the number of resource elements (REs)/PRBs or RUs, the terminal device  110  may adjust the number of REs/PRBs or RUs. In the embodiments where the allocated resource includes the reference number of repetitions, the terminal device  110  may adjust the number of repetitions. 
     For example, in the case of the adjustment of the number of repetitions, the terminal device  110  may determine the number of repetitions as a function of the determined TBS and reference TBS values using the equation (1): 
         K =ceil(Nrep*(TBS_new/TBS_ref))  (1)
 
     where TBS_ref represents the reference TBS, TBS_new represents the determined TBS, Nrep represents the reference number of repetitions allocated by the network device  120 . The function ceil( ) represents the operation of rounding up Nrep*(TBS_new/TBS_ref) to the nearest integer. If Nrep=64, TBS_ref=1000 and TBS_new=328, then K=21. In this case, the terminal device  110  may determine the number of repetitions as Nrep_new=21. 
     In some embodiments, the terminal device  110  may select the number of repetitions from a set of candidate numbers of repetitions which is defined or configured in the network  100 . For example, K calculated in the equation (1) is considered as a reference number (referred to as a second reference number) of repetitions. Then, the terminal device  110  selects the number for repetitions from the set of candidate numbers of repetitions. In the above case of K=21, if a set of candidate numbers of repetitions {1, 2, 4, 8, 16, 32, 64, 128} is defined, the terminal device  110  may select Nrep_new=32 that is the smallest value greater than or equal to 21. 
     In some embodiments, after the number of repetitions is selected from the candidate numbers based on the second reference number of repetitions, the terminal device  110  may further determine a transmission power for the selected number of repetitions. For example, the terminal device  110  may adjust the transmission power by: 
       min(10*log 10( K /Nrep_new)+Δ,0) dB
 
     where the parameter A represents power adjustment margin. The value of Δ may be configured according to actual needs. The transmission power may be adjusted as a function of the selected and reference TBS values or as a function of the selected and reference number of repetitions. 
     For example, Δ=0.5. In the case that K=21 but the number of repetitions is selected as Nrep_new=32, the terminal device  110  may adjusts its UL transmission power by 10*log 10(21/32)+0.5=−1.3 dB. 
     Similar to the TBS and resource adjustments, the power adjustment may also be enabled by the network device  120 . For example, as shown in  FIG.  2   , the terminal device  110  may receive ( 206 ) a further indication that the power adjustment is enabled by the network device  120 . 
     It is to be understood that although some embodiments are described in the scenario of the EDT, other grant-free scenarios are also applicable. In those scenarios, after the network device  120  configures certain set of resources based on a reference TBS, the terminal device  110  may also adjust the resources accordingly. 
     Compared with the adjustment of REs/PRBs/RUs, the adjustment of the number of repetitions allows low-complexity of the receiver processing at the network device  120 . The comparison of the processing complexity will be discussed below with reference  FIGS.  3 ( a ),  3 ( b ) and  3 ( c )  which illustrate example processing for blind decoding attempts at the network device  120  when the terminal device  110  uses different adjustment techniques. 
       FIG.  3 ( a )  shows example processing for blind decoding attempts with different numbers of repetitions. As shown in  FIG.  3 ( a ) , in the case that the number of repetitions is adjusted, for four different candidate TBSs  305 ,  310 ,  315  and  320 , the same receiver processing is performed, which may involve Discrete Fourier Transform (DFT), channel estimation, equalization, demodulation, Log Likelihood Ratio (LLR) calculation, Turbo Decoding, for example. Then, separate rate-matching and soft-combining are performed for the different candidate TBSs  305 ,  310 ,  315  and  320 . Furthermore, four separate soft buffers would be required. 
       FIG.  3 ( b )  shows example processing for blind decoding attempts with different numbers of REs/PRBs. As shown in  FIG.  3 ( b ) , in the case that the number of REs/PRBs is adjusted, separate receiver processing and then the rate-matching and soft-combining are performed for the different candidate TBSs  305 ,  310 ,  315  and  320 . Four separate buffers are required. 
       FIG.  3 ( c )  shows example processing for blind decoding attempts with different numbers of RUs. As shown in  FIG.  3 ( c ) , in the case that the number of RUs is adjusted, in the receiver processing, the same DFT is performed. Other receiver processing and then the rate-matching and soft-combining are separated for the different TBSs  305 ,  310 ,  315  and  320 . Four separate buffers are required. 
     Table 2 shows the comparisons of the receiver complexity with the different adjustment techniques as shown in  FIGS.  3 ( a ),  3 ( b ) and  3 ( c ) . 
     
       
         
           
               
               
            
               
                   
               
               
                   
                 Number of processing for 4 transport blocks 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                 Channel 
                   
                   
                   
                 Rate- 
                 Soft Buffer 
                 Turbo 
               
               
                 Technique 
                 DFT 
                 Estimation 
                 Equalization 
                 Demodulation 
                 LLR 
                 Matching 
                 Combining 
                 Decoding 
               
               
                   
               
               
                 Adjusting 
                 1 
                 1 
                 1 
                 1 
                 1 
                 4 
                 4 
                 4 
               
               
                 number of 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 repetitions 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Adjusting 
                 4 
                 4 
                 4 
                 4 
                 4 
                 4 
                 4 
                 4 
               
               
                 number of 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 subcarriers/ 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 PRBs 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Adjusting 
                 1 
                 4 
                 4 
                 4 
                 4 
                 4 
                 4 
                 4 
               
               
                 number of 
                   
                 (possible to 
                   
                   
                   
                   
                   
                   
               
               
                 resource 
                   
                 reduce to 1) 
                   
                   
                   
                   
                   
                   
               
               
                 units 
               
               
                   
               
            
           
         
       
     
     It can be seen that the adjustment of the number of repetitions results in minimum complexity at the network device  120  compared with other adjustment techniques. 
       FIG.  4    which shows a flowchart of an example method  400  in accordance with some embodiments of the present disclosure. The method  400  can be implemented at the terminal device  110  as shown in  FIG.  1   . For the purpose of discussion, the method  400  will be described with reference to  FIG.  1   . 
     At block  405 , the terminal device  110  transmits a random access preamble to the network device  120 . At block  410 , the terminal device  110  receives a random access response from the network device  120 . The random access response includes a resource allocated for a reference TBS. At block  415 , the terminal device  110  determines, based on the reference TBS, a TBS for transmitting data to the network device  120 . At block  420 , the terminal device  110  transmits the data to the network device  120  by using the determined TBS and the allocated resource. In some embodiments, the random access response may also include the reference TBS. 
     In some embodiments, the terminal device  110  may determine amount of the data to be transmitted to the network device. The terminal device  110  may further determine the TBS based on the amount of the data and the reference TBS. 
     In some embodiments, the terminal device  110  may receive, from the network device  120 , an indication that TBS adjustment is enabled by the network device. In response to receiving the indication that the TBS adjustment is enabled by the network device, the terminal device  110  may determine the amount of the data. 
     In some embodiments, the terminal device  110  may determine a set of candidate TBSs associated with the reference TBS, and then select the TBS from the set of candidate TBSs based on the amount of the data. 
     In some embodiments, the terminal device  110  may transmit, to the network device  120 , an indication that TBS selection is enabled by the terminal device  110 . 
     In some embodiments, the terminal device  110  may receive the random access response from the network device  120  by using downlink grant. In some other embodiments, the terminal device  110  may receive the reference TBS and the allocated resource from the network device  120  in uplink grant. 
     In some embodiments, the terminal device  110  may determine, from the allocated resource, a resource for transmitting the data. Then, the terminal device  110  may transmit the data to the network device in the determined resource by using the determined TBS. 
     In some embodiments, the terminal device  110  may receive, from the network device  120 , an indication that resource adjustment is enabled by the network device  120 . In response to receiving the indication that the resource adjustment is enabled by the network device  120 , the terminal device  110  may determine the resource from the allocated resource based on the determined TBS and the reference TBS. 
     In some embodiments, the allocated resource includes a first reference number of repetitions. In these embodiments, the terminal device  110  may determine, based on the first reference number of repetitions, the determined TBS and the reference TBS, the number of repetitions for transmitting the data. 
     In some embodiments, the terminal device  110  may determine a second reference number of repetitions based on the first reference number of repetitions, the determined TBS and the reference TBS. The terminal device  110  may further determining a set of the candidate numbers of repetitions associated with the second reference number of repetitions, and select the number of repetitions from the set of the candidate numbers of repetitions. 
     In some embodiments, the terminal device  110  may determine a transmission power for the selected number of repetitions, and transmit the data to the network device  120  by using the determined TBS, the determined number of repetitions and the determined transmission power. 
     In some embodiments, the terminal device  110  may receive, from the network device  120 , an indication that power adjustment is enabled by the network device  120 . Then, the terminal device  110  may determine the transmission power based on the selected number of repetitions and the second reference number of repetitions. 
     In some embodiments, the terminal device  110  may detect a maximum TBS in system information. The maximum TBS may be larger than the reference TBS. 
       FIG.  5    which shows a flowchart of an example method  500  in accordance with some embodiments of the present disclosure. The method  500  can be implemented at the network device  120  as shown in  FIG.  1   . For the purpose of discussion, the method  500  will be described with reference to  FIG.  1   . 
     At block  505 , the network device  120  receives a random access preamble from the terminal device  110 . At block  510 , the network device  120  transmits a random access response to the terminal device  110 . The random access response includes a resource allocated for a reference TBS for data transmission of the terminal device  110 . At block  515 , the network device  120  detects data from the terminal device  110  in the allocated resource. In some embodiments, the random access response may also include the reference TBS. 
     In some embodiments, the network device  120  may determine a set of candidate TBSs associated with the reference TBS. Then, the network device  120  may detect, based on the set of candidate TBSs, the data from the terminal device  110  in the allocated resource. 
     In some embodiments, the network device  120  may receive, from the terminal device  110 , an indication that TBS selection is enabled by the terminal device  110 . In response to receiving the indication that the TBS selection is enabled by the terminal device  110 , the network device  120  may determine the set of candidate TBSs. 
     In some embodiments, the network device  120  may transmit the random access response to the terminal device  110  by using downlink grant. In some other embodiments, the network device  120  may transmit the reference TBS and the allocated resource to the terminal device  110  in uplink grant. 
     In some embodiments, the network device  120  may transmit, to the terminal device  110 , an indication that TBS adjustment is enabled by the network device  120 . 
     In some embodiments, the network device  120  may transmit, to the terminal device  110 , an indication that resource adjustment is enabled by the network device  120 . 
     In some embodiments, the network device  120  may transmit, to the terminal device  110 , an indication that power adjustment is enabled by the network device  120 . 
     In some embodiments, the network device  120  may broadcast a maximum TBS in system information. The maximum TBS may be larger than the reference TBS. 
     It is to be understood that all operations and features related to the terminal device  110  and the network device  120  described above with reference to  FIGS.  1 ,  2  and  3   ( a )- 3 ( c ) are likewise applicable to the methods  400  and  500  and have similar effects. For the purpose of simplification, the details will be omitted. 
       FIG.  6    is a simplified block diagram of a device  600  that is suitable for implementing embodiments of the present disclosure. The device  600  can be implemented at or as at least a part of the terminal device  110  or a part of the network device  120  as shown in  FIG.  1   . 
     As shown, the device  600  includes a processor  610 , a memory  620  coupled to the processor  610 , a communication module  640  coupled to the processor  610 , and a communication interface (not shown) coupled to the communication module  640 . The memory  620  stores at least a program  630 . The communication module  640  is for bidirectional communications. The communication interface may represent any interface that is necessary for communication with a network element, such as Uu interface for communication between the eNB and the UE. 
     The program  630  is assumed to include program instructions that, when executed by the associated processor  610 , enable the device  600  to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to  FIGS.  1 - 5   . The embodiments herein may be implemented by computer software executable by the processor  610  of the device  600 , or by hardware, or by a combination of software and hardware. The processor  610  may be configured to implement various embodiments of the present disclosure. 
     The memory  620  may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory  620  is shown in the device  600 , there may be several physically distinct memory modules in the device  600 . The processor  610  may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device  600  may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor. 
     When the device  600  acts as the terminal device  110 , the processor  610  and the memory  620  may cooperate to cause the device  600  to implement the method  400  as discussed herein with reference to  FIG.  4   . When the device  600  acts as the network device  120 , the processor  610  and the memory  620  may cooperate to cause the device  600  to implement the method  500  as discussed herein with reference to  FIG.  5   . 
     All operations and features related to the terminal device  110  and the network device  120  described above with reference to  FIGS.  1 ,  2  and  3   ( a )- 3 ( c ) are likewise applicable to the device  600  and have similar effects. For the purpose of simplification, the details will be omitted. 
     Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. 
     The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the methods  400  and  500  as described above with reference to  FIGS.  4  and  5   . Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media. 
     Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server. 
     In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable media. 
     The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. 
     Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination. 
     Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. 
     Various embodiments of the techniques have been described. In addition to or as an alternative to the above, the following examples are described. The features described in any of the following examples may be utilized with any of the other examples described herein. 
     Example 1. A method comprising: at a terminal device, transmitting a random access preamble to a network device; receiving a random access response from the network device, the random access response including a resource allocated for a reference transport block size (TBS); determining, based on the reference TBS, a TBS for transmitting data to the network device; and transmitting the data to the network device by using the determined TBS and the allocated resource. 
     Example 2. The method of example 1, wherein the random access response further includes the reference TBS. 
     Example 3. The method of example 2, wherein receiving the random access response comprises: receiving the reference TBS and the allocated resource from the network device in uplink grant. 
     Example 4. The method of any of examples 1-3, wherein receiving the random access response comprises: receiving the random access response from the network device by using downlink grant. 
     Example 5. The method of any of examples 1-4, wherein determining the TBS comprises: determining amount of the data to be transmitted to the network device; and determining the TBS based on the amount of the data and the reference TBS. 
     Example 6. The method of example 5, wherein determining the amount of the data comprises: receiving, from the network device, an indication that TBS adjustment is enabled by the network device; and in response to receiving the indication that the TBS adjustment is enabled by the network device, determining the amount of the data. 
     Example 7. The method of example 5 or 6, wherein determining the TBS based on the amount of the data and the reference TBS comprises: determining a set of candidate TBSs associated with the reference TBS; and selecting the TBS from the set of candidate TBSs based on the amount of the data. 
     Example 8. The method of example 4, further comprising: transmitting, to the network device, an indication that TBS selection is enabled by the terminal device. 
     Example 9. The method of any of examples 1-8, wherein transmitting the data comprises: determining, from the allocated resource, a resource for transmitting the data; and transmitting the data to the network device in the determined resource by using the determined TBS. 
     Example 10. The method of example 9, wherein determining the resource comprises: receiving, from the network device, an indication that resource adjustment is enabled by the network device; and in response to receiving the indication that the resource adjustment is enabled by the network device, determining the resource from the allocated resource based on the determined TBS and the reference TBS. 
     Example 11. The method of example 10, wherein the allocated resource includes a first reference number of repetitions, and determining the resource comprises: determining, based on the first reference number of repetitions, the determined TBS and the reference TBS, the number of repetitions for transmitting the data. 
     Example 12. The method of example 11, wherein determining the number of repetitions comprises: determining a second reference number of repetitions based on the first reference number of repetitions, the determined TBS and the reference TBS; determining a set of the candidate numbers of repetitions associated with the second reference number of repetitions; and selecting the number of repetitions from the set of the candidate numbers of repetitions. 
     Example 13. The method of example 12, wherein transmitting the data to the network device in the determined resource comprises: determining a transmission power for the selected number of repetitions; and transmitting the data to the network device by using the determined TBS, the determined number of repetitions and the determined transmission power. 
     Example 14. The method of example 13, wherein determining the transmission power comprises: receiving, from the network device, an indication that power adjustment is enabled by the network device; and determining the transmission power based on the selected number of repetitions and the second reference number of repetitions. 
     Example 15. The method of any of examples 1-14, further comprising: detecting a maximum TBS in system information, the maximum TBS being larger than the reference TBS. 
     Example 16. A method comprising: at a network device, receiving a random access preamble from a terminal device; transmitting a random access response to the terminal device, the random access response including a resource allocated for a reference transport block size (TBS) for data transmission of the terminal device; and detecting data from the terminal device in the allocated resource. 
     Example 17. The method of example 16, wherein the random access response further includes the reference TBS. 
     Example 18. The method of example 17, wherein transmitting the random access response comprises: transmitting the reference TBS and the allocated resource to the terminal device in uplink grant. 
     Example 19. The method of any of examples 16-18, wherein transmitting the random access response comprises: transmitting the random access response to the terminal device by using downlink grant. 
     Example 20. The method of any of examples 16-19, wherein detecting the data comprises: determining a set of candidate TBSs associated with the reference TBS; and detecting, based on the set of candidate TBSs, the data from the terminal device in the allocated resource. 
     Example 21. The method of example 20, wherein determining the set of candidate TBSs comprises: receiving, from the terminal device, an indication that TBS selection is enabled by the terminal device; and in response to receiving the indication that the TBS selection is enabled by the terminal device, determining the set of candidate TBSs. 
     Example 22. The method of any of examples 16-21, further comprising: transmitting, to the terminal device, an indication that TBS adjustment is enabled by the network device. 
     Example 23. The method of any of examples 16-22, further comprising: transmitting, to the terminal device, an indication that resource adjustment is enabled by the network device. 
     Example 24. The method of any of examples 16-23, further comprising: transmitting, to the terminal device, an indication that power adjustment is enabled by the network device. 
     Example 25. The method of any of examples 16-24, further comprising: broadcasting a maximum TBS in system information, the maximum TBS being larger than the reference TBS. 
     Example 26. A device, comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the device to perform the method of any of examples 1-15. 
     Example 27. A device, comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the device to perform the method of any of examples 16-25. 
     Example 28. A computer readable storage medium storing a computer program thereon, the computer program, when executed by a processor, causing the processor to perform the method of any of examples 1-15. 
     Example 29. A computer readable storage medium storing a computer program thereon, the computer program, when executed by a processor, causing the processor to perform the method of any of examples 16-25. 
     Example 30. An apparatus comprising: means for transmitting, by a terminal device, a random access preamble to a network device; means for receiving a random access response from the network device, the random access response including a resource allocated for a reference transport block size (TBS); means for determining, based on the reference TBS, a TBS for transmitting data to the network device; and means for transmitting the data to the network device by using the determined TBS and the allocated resource. 
     Example 31. The apparatus of example 30, wherein the random access response further includes the reference TBS. 
     Example 32. The apparatus of example 31, wherein the means for receiving the random access response comprises: means for receiving the reference TBS and the allocated resource from the network device in uplink grant. 
     Example 33. The apparatus of any of examples 30-32, wherein the means for receiving the random access response comprises: means for receiving the random access response from the network device by using downlink grant. 
     Example 34. The apparatus of any of examples 30-33, wherein the means for determining the TBS comprises: means for determining amount of the data to be transmitted to the network device; and means for determining the TBS based on the amount of the data and the reference TBS. 
     Example 35. The apparatus of example 34, wherein the means for determining the amount of the data comprises: means for receiving, from the network device, an indication that TBS adjustment is enabled by the network device; and means for in response to receiving the indication that the TBS adjustment is enabled by the network device, determining the amount of the data. 
     Example 36. The apparatus of example 34 or 35, wherein the means for determining the TBS based on the amount of the data and the reference TBS comprises: means for determining a set of candidate TBSs associated with the reference TBS; and means for selecting the TBS from the set of candidate TBSs based on the amount of the data. 
     Example 37. The apparatus of example 36, further comprising: means for transmitting, to the network device, an indication that TBS selection is enabled by the terminal device. 
     Example 38. The apparatus of any of examples 30-37, wherein the means for transmitting the data comprises: means for determining, from the allocated resource, a resource for transmitting the data; and means for transmitting the data to the network device in the determined resource by using the determined TBS. 
     Example 39. The apparatus of example 38, wherein the means for determining the resource comprises: means for receiving, from the network device, an indication that resource adjustment is enabled by the network device; and means for in response to receiving the indication that the resource adjustment is enabled by the network device, determining the resource from the allocated resource based on the determined TBS and the reference TBS. 
     Example 40. The apparatus of example 39, wherein the allocated resource includes a first reference number of repetitions, and the means for determining the resource comprises: means for determining, based on the first reference number of repetitions, the determined TBS and the reference TBS, the number of repetitions for transmitting the data. 
     Example 41. The apparatus of example 40, wherein the means for determining the number of repetitions comprises: means for determining a second reference number of repetitions based on the first reference number of repetitions, the determined TBS and the reference TBS; means for determining a set of the candidate numbers of repetitions associated with the second reference number of repetitions; and means for selecting the number of repetitions from the set of the candidate numbers of repetitions. 
     Example 42. The apparatus of example 41, wherein the means for transmitting the data to the network device in the determined resource comprises: means for determining a transmission power for the selected number of repetitions; and means for transmitting the data to the network device by using the determined TBS, the determined number of repetitions and the determined transmission power. 
     Example 43. The apparatus of example 42, wherein the means for determining the transmission power comprises: means for receiving, from the network device, an indication that power adjustment is enabled by the network device; and means for determining the transmission power based on the selected number of repetitions and the second reference number of repetitions. 
     Example 44. The apparatus of any of examples 30-43, further comprising: means for detecting a maximum TBS in system information, the maximum TBS being larger than the reference TBS. 
     Example 45. A apparatus comprising: means for receiving, by a network device, a random access preamble from a terminal device; means for transmitting a random access response to the terminal device, the random access response including a resource allocated for a reference transport block size (TBS) for data transmission of the terminal device; and means for detecting data from the terminal device in the allocated resource. 
     Example 46. The apparatus of example 45, wherein the random access response further includes the reference TBS. 
     Example 47. The apparatus of example 46, wherein the means for transmitting the random access response comprises: means for transmitting the reference TBS and the allocated resource to the terminal device in uplink grant. 
     Example 48. The apparatus of any of examples 45-47, wherein the means for transmitting the random access response comprises: means for transmitting the random access response to the terminal device by using downlink grant. 
     Example 49. The apparatus of any of examples 45-48, wherein the means for detecting the data comprises: means for determining a set of candidate TBSs associated with the reference TBS; and means for detecting, based on the set of candidate TBSs, the data from the terminal device in the allocated resource. 
     Example 50. The apparatus of example 49, wherein the means for determining the set of candidate TBSs comprises: means for receiving, from the terminal device, an indication that TBS selection is enabled by the terminal device; and means for in response to receiving the indication that the TBS selection is enabled by the terminal device, determining the set of candidate TBSs. 
     Example 51. The apparatus of any of examples 45-50, further comprising: means for transmitting, to the terminal device, an indication that TBS adjustment is enabled by the network device. 
     Example 52. The apparatus of any of examples 45-51, further comprising: means for transmitting, to the terminal device, an indication that resource adjustment is enabled by the network device. 
     Example 53. The apparatus of any of examples 45-52, further comprising: means for transmitting, to the terminal device, an indication that power adjustment is enabled by the network device. 
     Example 54. The apparatus of any of examples 45-53, further comprising: means for broadcasting a maximum TBS in system information, the maximum TBS being larger than the reference TBS.