Random access procedure

Abstract

Exemplary embodiments of this disclosure provide methods, devices, and computer-readable storage media for random access procedures. [Solution] The method comprises the following steps: sending a random access request to a network device using a random access procedure in a terminal device; determining, in response to receiving an uplink grant from the network device in the random access procedure, whether the first size of a first data unit indicated by the uplink grant matches the second size of a second data unit stored in the buffer of the terminal device; and determining, in response to determining that the first size does not match the second size, a first portion of the second data unit for subsequent transmission.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of telecommunications, and more specifically, to methods, devices, and computer-readable storage media for random access procedures.

Background Art

[0002] In 5G New Radio (NR), multi-beam operation is provided. Support for multi-beam operation in NR includes beam quality measurement, beam quality reporting, beam allocation, and a recovery mechanism when the allocated beam quality is not good enough. NR supports multi-beam operation at all stages of wireless operations such as initial / random access, paging, data / control transmission, data / control reception, and mobility handling.

[0003] In a multi-beam operation scenario in NR, a user equipment (UE) can switch between a beam to which a contention-free random access (CFRA) resource is allocated and a beam to which a contention-based random access (CBRA) resource is allocated. However, in LTE, the communication network allocates the CFRA resources for the entire cell to the UE. That is, there is no switching between CFRA and CBRA. Therefore, when a beam switching procedure is performed in NR, the size of the media access control (MAC) protocol data unit (PDU) permitted within the uplink grant allocated during a random access (RA) procedure and transmitted from a network device (e.g., gNB) may be different from the size of the MAC PDU obtained from the UE's Msg3 buffer.

Summary of the Invention

[0004] Generally, exemplary embodiments of the present disclosure provide methods, devices, and computer-readable storage media for random access procedures.

[0005] In a first embodiment, a method is provided that is implemented in a terminal device. The method comprises the terminal device sending a random access request to a network device in a random access procedure; in response to receiving an uplink grant of the terminal device from the network device in the random access procedure, determining whether a first size of a first data unit indicated by the uplink grant matches a second size of a second data unit stored in a buffer of the terminal device; and determining a first portion of the second data unit for subsequent transmission in response to determining that the first size does not match the second size.

[0006] A second embodiment provides a method implemented in a network device. The method comprises receiving a random access request from a terminal device in a random access procedure, and, in response to receiving the random access request, sending an uplink grant of the terminal device indicating the first size of the first data unit to the terminal device, so that the terminal device determines whether the first size of the first data matches the second size of the second data unit stored in the terminal device's buffer.

[0007] In a third embodiment, a terminal device is provided. The device comprises at least one processor and at least one memory containing computer program code. The at least one memory and the computer program code, together with the at least one processor, are configured to cause the device to perform at least the method according to the first embodiment.

[0008] In a fourth aspect, a network device is provided. The device comprises at least one processor and at least one memory containing computer program code. The at least one memory and the computer program code, together with the at least one processor, are configured to cause the device to perform at least the method according to the second aspect.

[0009] In a fifth embodiment, an apparatus is provided that includes means for performing the steps of the method according to the first embodiment.

[0010] In a sixth embodiment, an apparatus is provided that includes means for performing the steps of the method according to the second embodiment.

[0011] In the seventh aspect, a computer-readable medium is provided on which a computer program is stored, and the computer program, once executed by at least one processor of the device, causes the device to perform the method according to the first aspect.

[0012] In the eighth aspect, a computer-readable medium is provided on which a computer program is stored, and the computer program, once executed by at least one processor of the device, causes the device to perform the method according to the second aspect.

[0013] It should be understood that the Summary of the Invention section is not intended to identify any important or essential features of the embodiments of this disclosure, nor is it intended to be used to limit the scope of this disclosure. Other features of this disclosure will be readily apparent through the following description.

[0014] The above and other purposes, features, and advantages of this disclosure will become more apparent through a more detailed description of some exemplary embodiments of this disclosure in the accompanying drawings. [Brief explanation of the drawing]

[0015] [Figure 1] An exemplary communication system 100 in which exemplary embodiments of the present disclosure may be implemented is shown. [Figure 2] The following illustrations illustrate an exemplary process 200 of a random access procedure according to some exemplary embodiments of the present disclosure. [Figure 3] A flowchart of an exemplary method 300 of a random access procedure according to some exemplary embodiments of the present disclosure is shown. [Figure 4] A flowchart of an exemplary method 400 of a random access procedure according to some exemplary embodiments of the present disclosure is shown. [Figure 5] This is a simplified block diagram of a device suitable for carrying out exemplary embodiments of the present disclosure. [Modes for carrying out the invention]

[0016] Throughout the drawing, the same or similar reference numbers represent the same or similar elements.

[0017] The principles of this disclosure are described here with reference to several exemplary embodiments. These embodiments are described for illustrative purposes only and should be understood as assisting those skilled in the art in understanding and implementing this disclosure, without implying any limitation on the scope of this disclosure. The disclosure described herein can be implemented in various ways other than those described below.

[0018] In the following description and claims, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this disclosure belongs, unless otherwise defined.

[0019] As used herein, the term “communication network” refers to a network that conforms to any preferred communication standard or protocol, such as Long-Term Evolution (LTE), LTE-Advanced (LTE-A), and 5G NR, and uses any preferred communication technology, including, for example, Multiple Input Multiple Output (MIMO), OFDM, Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), Code Division Multiplexing (CDM), Bluetooth, ZigBee, Machine-Type Communication (MTC), eMBB, mMTC, and uRLLC technology. For the purposes of this discussion, in some embodiments, an LTE network, an LTE-A network, a 5G NR network, or any combination thereof will be treated as an example of a communication network.

[0020] As used herein, the term “network device” refers to any suitable device on the network side of a communications network. Network devices may include any suitable device within the access network of a communications network, such as base stations (BS), relays, access points (AP), node Bs (NodeB or NB), advanced node Bs (eNodeB or eNB), gigabit node Bs (gNB), remote radio modules (RRUs), radio headers (RHs), remote radio heads (RRHs), and low-power nodes such as femto and pico. For the purposes of this discussion, in some embodiments, eNBs are treated as examples of network devices.

[0021] Network devices may also include any suitable devices within the core network, such as multistandard radio (MSR) radio equipment like multistandard radio MSRBS, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), multicell / multicast coordinating entities (MCEs), mobile switching stations (MSCs) and MMEs, operation and management (O&M) nodes, operational support system (OSS) nodes, self-organizing network (SON) nodes, positioning nodes such as advanced service-providing mobile location centers (E-SMLCs), and / or mobile information terminals (MDTs).

[0022] As used herein, the term "terminal device" refers to a device that is configured to communicate, arranged to communicate, and / or operable to communicate with a network device or a further terminal device in a communication network. Communication may include transmitting and / or receiving wireless signals using electromagnetic signals, radio waves, infrared signals, and / or other types of signals suitable for transmitting information wirelessly. 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 a network device at a predetermined schedule when triggered by an internal event or an external event, or in response to a request from the network side.

[0023] Examples of terminal devices include, but are not limited to, user equipment (UE) such as smartphones, wireless-enabled tablet computers, laptop embedded equipment (LEE), laptop-mounted equipment (LME), and / or wireless in-home equipment (CPE). For the purpose of discussion, in the following, some embodiments are described with reference to UE as an example of a terminal device, and the terms "terminal device" and "user equipment" (UE) may be used interchangeably in the context of the present disclosure.

[0024] As used herein, the term "cell" refers to the area covered by a wireless signal transmitted by a network device. Terminal devices within the cell can receive services provided by the network device and access the communication network via the network device.

[0025] As used herein, the term "circuit" (a) a circuit implementation with only hardware (such as an implementation with only analog and / or digital circuits), (b) A combination of hardware circuits and software, e.g., (if applicable), (i) a combination of analog and / or digital hardware circuit(s) and software / firmware, and (ii) a hardware processor(s) (including digital signal processor(s)) having software, software, and optionally part of the memory(ies) that cooperate to cause a device such as a mobile phone or a server to perform various functions. (c) Hardware circuit(s) that require software (e.g., firmware) for operation, and / or processor(s) such as microprocessor(s) or part of microprocessor(s) where software may not be present if not required for operation. May refer to one or more or all of the above.

[0026] This definition of circuit applies to all uses of this term in this application, including all claims. As a further example, the term "circuit" as used in this application also includes simply a hardware circuit or processor (or processors), or a part of a hardware circuit or processor, and the implementation of software and / or firmware associated therewith (or therewith). The term "circuit" also includes, for example, a baseband integrated circuit or a processor integrated circuit for a mobile device, or a similar integrated circuit within a server, a cellular network device, or other computing or network device, if applicable to a particular claim element.

[0027] As used herein, the singular forms "a," "an," and "the" are intended to include the plural unless otherwise clearly indicated by the context. The term "includes" and its variations should be interpreted as an open term meaning "includes, but not limited to." The term "based on" should be interpreted as "at least partially based on." The terms "one embodiment" and "an embodiment" should be interpreted as "at least one embodiment." The term "another embodiment" should be interpreted as "at least one other embodiment." Other explicit and implicit definitions may be included below.

[0028] Figure 1 shows a communication network 100 in which embodiments of the present disclosure may be implemented. The communication network 100 may conform to any existing or future preferred protocol or standard. In some embodiments, the communication network 100 may be an LTE (or LTE-A) network, an NR network, or a combination thereof.

[0029] The communication network 100 comprises a network device 110. The network device 110 provides services to a terminal device 120 within a cell 111. The number of network devices and terminal devices is shown for illustrative purposes only, without implying any limitation. The communication system 100 may include any suitable number of network devices and terminal devices. Communication between the network device 110 and the terminal device 120 may utilize any suitable existing or future-developed technologies.

[0030] The issue of grants of different sizes provided by the communication network for MESSAGE3 (Msg3) transmission was considered in LTE. Msg3 can transmit Layer 2 and Layer 3 messages from terminal device 120 to network device 110, such as radio resource control connection requests for initial access or C-RNTI medium access control (MAC) control elements (CE) for random access in connection mode. If the uplink grant provided in the Random Access Response (RAR) to the same group of Random Access Preambles (RAPs) is of a different size than the previous uplink grant allocated during that random access procedure (e.g., the first uplink grant), this was considered an extremely rare case, and the behavior of terminal device 120 within the random access procedure was undefined. In LTE, the communication network allocates cell-wide CFRA resources to terminal device 120. In other words, there is no switching between CFRA and CBRA within a single random access procedure.

[0031] 5G New Radio (NR) offers multi-beam operation. Therefore, unlike LTE, where CFRA resources are allocated to a single cell (e.g., cell 111 shown in Figure 1), in NR, the communication network can allocate CFRA resources only to a subset of beams within cell 111, rather than all of them, because allocating CFRA resources to all beams of all UEs can be too costly and thus defeat the purpose of beamforming.

[0032] Therefore, in the case of multi-beam operation in NR, user equipment (UE), such as the terminal device 120 shown in Figure 1, can move within the cell and change beams. The terminal device 120 can switch between a beam with one type of RA resource and several other beams with another type of RA resource. For example, within cell 111, the terminal device can switch between a beam assigned a CFRA (Critical Free Random Access) resource and a beam assigned a CBRA (Critical Based Random Access) resource.

[0033] When terminal device 120 switches from CFRA to CBRA, there are no problems caused by Msg3, which can only be generated during the first CBRA attempt. In the CFRA case, the RA procedure is already successful upon receiving Msg2 from gNB (e.g., network device 110 shown in Figure 1).

[0034] However, if terminal device 120 switches from CBRA to CFRA, Msg3 should be generated and transmitted in CFRA as well, according to TS 38.321, because the Hybrid Auto-Retransmission Request (Hybrid ARQ or HARQ) buffer should be flushed upon completion of the RA procedure, but the Msg3 buffer should not be flushed. Furthermore, in a HARQ entity, if an uplink grant is received in RAR and a Medium Access Control (MAC) protocol data unit (PDU) is present in the Msg3 buffer, the MAC PDU may be retrieved from the Msg3 buffer.

[0035] In the above example, if the grant provided by RAR for a CFRA preamble transmission is the same size as the grant previously provided in response to a CBRA preamble transmission, the MAC PDU in the Msg3 buffer can be transmitted with the provided grant. However, two different preamble groups, namely preamble group A and group B, are defined for CBRA. Typically, terminal device 120 selects a sequence from these two groups based on the size and radio condition of the uplink packet. This helps network device 110 calculate the physical uplink shared channel (PUSCH) resources required for uplink forwarding by terminal device 120. Preambles from group A are used for small or large packets in poor radio conditions. Preambles from group B are used for large packets in good radio conditions. In this example, network device 110 does not know whether terminal device 120 attempted CBRA before CFRA, or which group of preamble was applied when the CBRA preamble was transmitted. Therefore, it is expected that problems caused by different Msg3 grant sizes will frequently occur in NR.

[0036] Furthermore, given the fact that MAC PDUs in the Msg3 buffer, for example, at least the handover (HO) completion command (RRCReconfigurationComplete) segment, can be multiplexed, it is undesirable to lose such data and delay the completion of the HO procedure (as this would require retransmission at the RLC level). If CFRA is selected for the preamble trial, terminal device 120 uses the Msg3 buffer to transmit the first uplink data in the RA procedure. If CFRA is selected for the preamble trial, the RA procedure is successfully completed upon RAR reception.

[0037] Therefore, regarding the fact that the size of the MAC PDU, indicated by the uplink grant allocated during the RA procedure and transmitted from network device 110, may differ from the size of the MAC PDU obtained from the Msg3 buffer of terminal device 120, several methods were considered to resolve this issue.

[0038] One approach proposed was that, during resource selection for random access for handover, if Msg3 was sent in the current random access procedure, terminal device 120 should not select a random access preamble from among the CFRA preambles. However, this approach wastes dedicated resources in the CFRA and can unnecessarily increase the load among competing base preambles.

[0039] A further approach has been proposed in which the multiplexing and assembly entities may include multiple MAC sub-PDUs from the acquired MAC PDU in subsequent uplink transmissions. If the size of the uplink grant does not match the previous uplink grant provided according to the CBRA preamble, the Msg3 buffer may be flushed and a new MAC PDU may be acquired from the multiplexing and assembly entities. However, this approach may result in data loss.

[0040] As an option for flashing Msg3, MAC may indicate data multiplexed with MAC PDU, in which case the RLC PDU can be regenerated and multiplexed again. This technique may be suitable for data processing but cannot function for MAC control elements (CEs).

[0041] The principles and embodiments of this disclosure are described in detail below with reference to Figure 2, which shows a process 200 according to an exemplary embodiment of this disclosure. For illustrative purposes, the process 200 is described with reference to Figure 1. The process 200 may include a random access procedure.

[0042] Figure 2 illustrates an exemplary process 200 of a random access procedure according to some exemplary embodiments of the present disclosure.

[0043] As shown in Figure 2, when terminal device 120 performs random access, terminal device 120 sends a random access request, i.e., a random access preamble (RAP), to network device 110. In the context of this disclosure, the RAP is also referred to as "MESSAGE1" or "Msg1". The RAP is a signature code sequence that serves as an identifier for terminal device 120. Depending on whether the RAP is UE-specific, random access procedures are classified into conflict-free random access (CFRA) procedures and conflict-based random access (CBRA) procedures. As a result, terminal device 120 may send different random access preambles, i.e., CFRA preambles or CBRA preambles, to network device 110. As mentioned above, in a CBRA procedure, terminal device 120 may select a CBRA preamble from group A and group B. Terminal device 120 may select a sequence from these two groups based on the size of the uplink packet and the radio state.

[0044] When network device 110 detects a RAP preamble from terminal device 120, it may respond to a random access request by sending a Random Access Response (RAR) (also referred to in the context of this disclosure as "MESSAGE2" or "Msg2") to terminal device 120 based on the received RAP preamble.220 A RAR may be scheduled via actual messages on the Physical Downlink Control Channel (PDCCH) and the Physical Downlink Shared Channel (PDSCH). A RAR may include, for example, a Timing Advance Command (TAC) for UL timing matching, an uplink grant, and a temporary cell radio network identifier to terminal device 120.

[0045] In a non-compete random access procedure, or non-compete-based random access procedure, the terminal device 120 sends a dedicated RAP to the network device 110. When the terminal device 120 receives the RAR sent by the network device 110, the terminal device 120 determines that the random access procedure has succeeded.

[0046] In a competition-based random access procedure, after terminal device 120 receives a RAR, terminal device 120 may send a message (also referred to as "MESSAGE3" or "Msg3") to network device 110 over a physical uplink shared channel (PUSCH). As previously stated, Msg3 may convey Layer 2 and Layer 3 messages from terminal device 120 to network device 110, such as a radio resource control connection request for initial access or a C-RNTI MAC CE for random access in connection mode. When terminal device 120 receives a RAR from network device 110, terminal device 120 may obtain an uplink grant included in the RAR, which indicates an uplink grant available for terminal device 120 to send its Msg3.

[0047] As described above, terminal device 120 may send preambles from different groups based on the size of the uplink packet and the radio state, and network device 110 may assign an uplink grant corresponding to terminal device 120 sending Msg3. In this case, the uplink grant for sending Msg3 included in the RAR may match the uplink grant in terminal device 120's Msg3 buffer.

[0048] As shown in Figure 2, terminal device 120 determines whether the first size of the first data unit indicated by the uplink grant matches the second size of the second data unit stored in the buffer of terminal device 120. The first and second data units may be referred to as MAC PDUs. The buffer may be referred to as the Msg3 buffer of terminal device 120.

[0049] In some embodiments, to determine whether the first size matches the second size, the terminal device 120 may determine the second size based on a Msg3 sent from the terminal device 120's Msg3 buffer. The terminal device may further determine the first size from an uplink grant sent from the network device 110. The terminal device 120 may compare the first size to the second size to determine whether the first size does not match the second size.

[0050] In some exemplary embodiments, Msg3 may represent at least one media access control element (MAC CE). In some exemplary embodiments, the MAC CE may comprise at least one of a C-RNTI MAC CE, a buffer status report BSR, and a power headroom report PHR.

[0051] Generally, a BSR is a type of MAC CE from a UE (e.g., terminal device 120) to a gNB (e.g., network device 110) that transmits information about the amount of data to be sent in the UE's buffer.

[0052] A BSR can refer to various types of BSRs. For example, a BSR may include a regular BSR, a periodic BSR, and a padding BSR. A regular BSR is sent when new data arrives in the buffer and the priority of the new data is higher than that already waiting in the buffer. A periodic BSR is sent at a predefined interval. The gNB may pre-configure the periodicity for the UE using an RRC message (e.g., RRCConnectionReconfiguration). Furthermore, a padding BSR is sent so that the BSR can be sent using the padding bit space if the number of padding bits in the data message is greater than the size of the padding BSR. If a full BSR does not fit the available padding bits, the padding BSR may consist of a shortened BSR. In this case, the BSR is shortened, and only the highest priority data is reported by the terminal device 120 to the network device 110.

[0053] Generally, PHR can indicate the amount of transmit power remaining in the UE.

[0054] As shown in Figure 2, if the terminal device 120 determines that the first size does not match the second size, the terminal device 120 determines the first portion of the second data unit for subsequent transmission.

[0055] In some exemplary embodiments, a subsequent transmission may comprise at least one of the following: a transmission associated with an uplink grant provided in a Random Access Response (RAR); and a transmission associated with a further uplink grant different from the said uplink grant.

[0056] In some exemplary embodiments, the terminal device 120 may determine whether the second size matches the first size. If the terminal device determines that the second size does not match the first size, the terminal device 120 may discard some portions of the second data unit for subsequent transmission, or may not consider some portions of the second data unit for subsequent transmission.

[0057] In some exemplary embodiments, the terminal device 120 may discard the shortened BSR from the second data unit.

[0058] Alternatively or additionally, the terminal device 120 may discard the padding BSR from the second data unit.

[0059] Alternatively or additionally, the terminal device 120 may discard the PHR from the second data unit.

[0060] Alternatively or additionally, the terminal device 120 may adjust the size of the shortened BSR. For example, the shortened BSR may be adjusted to fit the available size, i.e., the number of reported logical channel groups (LCGs) may be changed. Inevitably, the bitmap may reflect the addition / removal of reported LCGs. Adjusting the size of the shortened BSR may be limited to cases of reducing the size. It should be understood that for embodiments of the UE, deleting information may be easier than creating additional information. In this way, up-to-date BSR information may be provided.

[0061] Alternatively or additionally, terminal device 120 may discard regular / periodic BSRs and / or PHRs. Furthermore, regular / periodic BSRs and / or PHRs cannot be canceled until they are included in a grant scheduled by C-RNTI or CS-RNTI. Since BSRs / PHRs are newly generated for subsequent transmissions, this technique is intended to provide the most up-to-date information available regarding the buffer status and power headroom of terminal device 120.

[0062] In some exemplary embodiments, if the terminal device determines that the second size does not match the first size, the terminal device 120 may determine whether the random access procedure has completed successfully by receiving an uplink grant. If the terminal device 120 determines that the random access procedure has completed successfully, the terminal device may discard the C-RNTI medium access control MAC control element MAC CE from the second data unit.

[0063] In some exemplary embodiments, if the terminal device 120 determines that the second size does not match the first size, the terminal device 120 may determine whether a conflict-free random access preamble has been transmitted. If the terminal device 120 determines that a conflict-free random access preamble has been transmitted, the terminal device may discard the C-RNTI medium access control MAC control element MAC CE from the second data unit.

[0064] In some exemplary embodiments, the terminal device 120's determination of whether the random access procedure has been successfully completed may include determining that the uplink grant and / or RAR is addressed to at least one of the cell radio network temporary identifier C-RNTI and the random access radio network temporary identifier RA-RNTI.

[0065] In the CFRA procedure, terminal device 120 sends a dedicated RAP to network device 110, and when terminal device 120 receives the RAR sent by network device 110, terminal device 120 determines that the random access was successful. Therefore, the example described here may relate to the random access procedure during the transition from the CBRA procedure to the CFRA procedure for terminal device 120. In other words, it is not necessary to send the C-RNTI MAC CE to network device 110.

[0066] This solution avoids unnecessary transmission overhead because the terminal device 120 is already identified from the transmitted CFRA preamble. Furthermore, since the network device 110 does not expect to receive a C-RNTI MAC CE in response to the transmission of the CFRA preamble, this solution prevents the terminal device 120 from transmitting any other type of MAC PDU.

[0067] In some exemplary embodiments, other MAC CEs multiplexed with the acquired MAC PDU may be indicated in the multiplexing and assembly entities so as to be included in the subsequent uplink transmission. In this way, the other MAC CEs to be multiplexed can be included in the subsequent transmission, thus avoiding the loss of control information during Msg3 reconstruction.

[0068] As shown in Figure 2, the terminal device 120 transmits at least a portion of the first part of the second data unit to the network device 250 in the first data unit. The remaining portion of the first part may be transmitted in a subsequent transmission.

[0069] Through the embodiments described above, for each uplink grant, the HARQ entity of the terminal device 120 must identify the HARQ process associated with that grant. For each identified HARQ process, If the received grant is not addressed to the temporary C-RNTI in the PDCCH, and the New Data Indicator (NDI) provided in the associated HARQ information has been switched compared to the value at the time of the previous transmission in this transfer block (TB) of this HARQ process, or If an uplink grant is received on the PDCCH of C-RNTI and the HARQ buffer of the identified process is empty, or If an uplink grant is received in a random access response, or If an uplink grant is part of a bundle of configured grants and can be used for initial transmission in accordance with section 6.1.2.3 of TS 38.214[7], and no MAC PDU has been obtained for this bundle, If a MAC PDU exists in the Msg3 buffer and the uplink grant is received in a random access response, If the uplink grant size does not match the size of the MAC PDU in the Msg3 buffer, The multiplexing and assembly entities are instructed to include the MAC sub-PDUs from the MAC PDU in the Msg3 buffer, excluding the MAC sub-PDU containing the shortened BSR MAC CE, in subsequent uplink transmissions (if any) (if any). The MAC PDU sent from the multiplexed and assembly entities is obtained and stored in the Msg3 buffer. If the uplink grant size is equal to the size of the MAC PDU in the Msg3 buffer, Obtain the MAC PDU to be sent from the Msg3 buffer. If no MAC PDU is present in the Msg3 buffer and the uplink grant is received in a random access response, Retrieve MAC PDUs sent from multiplexed and assembly entities (if any).

[0070] Alternatively or additionally, through the embodiments described above, with respect to each uplink grant, the HARQ entity of the terminal device 120 must identify the HARQ process associated with that grant. For each identified HARQ process, If the received grant is not addressed to the temporary C-RNTI in the PDCCH, and the New Data Indicator (NDI) provided in the associated HARQ information has been switched compared to the value at the time of the previous transmission of this transfer block (TB) in this HARQ process, or If an uplink grant is received on the PDCCH of C-RNTI and the HARQ buffer of the identified process is empty, or If an uplink grant is received in a random access response, or If an uplink grant is part of a bundle of configured grants and can be used for initial transmission in accordance with section 6.1.2.3 of TS 38.214[7], and no MAC PDU has been obtained for this bundle, If a MAC PDU exists in the Msg3 buffer and an uplink grant is received in a random access response scheduled by a PDCCH addressed to RA-RNTI or C-RNTI, If the uplink grant size does not match the size of the MAC PDU in the Msg3 buffer, This random access response indicates that the random access procedure has completed successfully. The multiplexing and assembly entities are instructed to include, from the MAC PDU in the Msg3 buffer, MAC sub-PDUs other than those containing abbreviated BSR MAC CE or C-RNTI MAC CE, in subsequent uplink transmissions (if any) (if any). The MAC PDU sent from the multiplexed and assembly entities is obtained and stored in the Msg3 buffer. If the uplink grant size is equal to the size of the MAC PDU in the Msg3 buffer, Obtain the MAC PDU to be sent from the Msg3 buffer. If no MAC PDU is present in the Msg3 buffer and the uplink grant is received in a random access response, Retrieve MAC PDUs sent from multiplexed and assembly entities (if any).

[0071] Thus, according to embodiments of the present invention, the problem arising from the mismatch between the uplink grant indicated in RAR and the MAC PDU in the Msg3 buffer can be resolved by reconstructing the MAC CE of the MAC PDU.

[0072] Further details of the exemplary embodiments described herein will be explained with reference to Figures 3 and 4.

[0073] Figure 3 shows a flowchart of an exemplary method 300 of a random access procedure according to some exemplary embodiments of the present disclosure. Method 300 may be performed on the terminal device 120 shown in Figure 2. For descriptive purposes, Method 300 will be described with reference to Figure 2.

[0074] At step 310, terminal device 120 sends a random access request to the network device using a random access procedure.

[0075] In some exemplary embodiments, the terminal device 120 may transmit one of the following: a non-compete random access preamble and a competition-based random access preamble.

[0076] In step 320, when terminal device 120 receives an uplink grant from network device 110 using a random access procedure, terminal device 120 determines whether the first size of the first data unit indicated by the uplink grant matches the second size of the second data unit stored in the terminal device's buffer.

[0077] In some exemplary embodiments, the second data unit may comprise at least one of the following MAC CEs: C-RNTI, BSR, and PHR.

[0078] In some exemplary embodiments, the BSR may comprise at least one of a shortened BSR, a padding BSR, a normal BSR, and a periodic BSR.

[0079] If the terminal device 120 determines in 330 that the first size does not match the second size, the terminal device 120 determines the first portion of the second data unit for subsequent transmission, based at least on the first size.

[0080] In some exemplary embodiments, the terminal device 120 may determine whether the second size matches the first size. If the second size does not match the first size, the terminal device may perform at least one of the following actions: discard the shortened buffer status report BSR from the second data unit; discard the padding buffer status report BSR from the second data unit; discard the regular BSR from the second data unit; discard the periodic BSR from the second data unit; discard the power headroom report PHR from the second data unit; or adjust the size of the shortened BSR.

[0081] In some exemplary embodiments, the terminal device 120 may determine whether the second size matches the first size. If the second size does not match the first size, the terminal device 120 may determine whether the random access procedure has completed successfully by receiving an uplink grant. If the terminal device 120 determines that the random access procedure has completed successfully, the terminal device 120 may discard the C-RNTI media access control MAC control element MAC CE from the second data unit.

[0082] In some exemplary embodiments, the terminal device 120 may determine whether the second size matches the first size. If the second size does not match the first size, the terminal device 120 may determine whether a conflict-free random access preamble has been transmitted. If the terminal device 120 determines that a conflict-free random access preamble has been transmitted, the terminal device may discard the C-RNTI medium access control MAC control element MAC CE from the second data unit.

[0083] In some exemplary embodiments, the terminal device 120's determination of whether the random access procedure has been successfully completed may include determining that the uplink grant is addressed to at least one of the cell radio network temporary identifier C-RNTI and the random access radio network temporary identifier RA-RNTI.

[0084] In some exemplary embodiments, a subsequent transmission may include at least one of a transmission associated with an uplink grant and a transmission associated with a further uplink grant different from the said uplink grant.

[0085] In some exemplary embodiments, the terminal device 120 may further transmit at least a portion of the first part of the second data unit to the network device in the first data unit.

[0086] Figure 4 shows a flowchart of an exemplary method 400 of a random access procedure according to some exemplary embodiments of the present disclosure. Method 400 may be implemented on the network device 110 shown in Figure 2. For descriptive purposes, Method 400 will be described with reference to Figure 2.

[0087] At 410, the network device 110 receives a random access request from the terminal device 120 using a random access procedure.

[0088] In some exemplary embodiments, the network device 110 may receive one of the following: a non-conflict random access preamble and a conflict-based random access preamble.

[0089] At 420, the network device 110 sends an uplink grant to the terminal device 120 indicating the first size of the first data unit, so that the terminal device can determine whether the first size of the first data unit matches the second size of the second data unit stored in the terminal device's buffer.

[0090] In some exemplary embodiments, the second data unit may comprise at least one of the following MAC CEs: C-RNTI, BSR, and PHR.

[0091] In some exemplary embodiments, the BSR may comprise at least one of a shortened BSR, a padding BSR, a normal BSR, and a periodic BSR.

[0092] In some exemplary embodiments, the network device 110 may further receive at least a portion of the first part of the second data unit from the terminal device in the first data unit.

[0093] In some exemplary embodiments, an apparatus capable of performing Method 300 (e.g., terminal device 120) may comprise means for performing each step of Method 300. These means can be implemented in any preferred form. For example, the means may be implemented in a circuit or a software module.

[0094] In some exemplary embodiments, the device includes, at the terminal device, means for sending a random access request to a network device in a random access procedure; means for determining, in response to receiving an uplink grant from the network device at the random access procedure, whether a first size of a first data unit indicated by an uplink grant matches a second size of a second data unit stored in the terminal device's buffer; and means for determining a first portion of the second data unit for subsequent transmission in response to determining that the first size does not match the second size.

[0095] In some exemplary embodiments, means for sending a random access request may include means for sending one of a non-conflict random access preamble and a conflict-based random access preamble.

[0096] In some exemplary embodiments, the second data unit may comprise at least one of the following MAC CEs: C-RNTI, BSR, and PHR.

[0097] In some exemplary embodiments, the BSR may comprise at least one of a shortened BSR, a padding BSR, a normal BSR, and a periodic BSR.

[0098] In some exemplary embodiments, the means for determining the first portion may include, in response to determining that the second size does not match the first size, means for performing at least one of the following: discarding a shortened buffer status report BSR from the second data unit; discarding a padding buffer status report BSR from the second data unit; discarding a regular BSR from the second data unit; discarding a periodic BSR from the second data unit; discarding a power headroom report PHR from the second data unit; and adjusting the size of the shortened BSR.

[0099] In some exemplary embodiments, means for determining the first portion may include, upon determining that the second size does not match the first size, means for determining whether the random access procedure has been successfully completed by receiving an uplink grant, and means for discarding the C-RNTI medium access control MAC control element MAC CE from the second data unit upon determining that the random access procedure is deemed to have been successfully completed.

[0100] In some exemplary embodiments, means for determining whether a random access procedure has been successfully completed may include means for determining that the uplink grant is addressed to at least one of the cell radio network temporary identifier C-RNTI and the random access radio network temporary identifier RA-RNTI.

[0101] In some exemplary embodiments, a subsequent transmission may include at least one of a transmission associated with an uplink grant and a transmission associated with a further uplink grant different from the said uplink grant.

[0102] In some exemplary embodiments, the device may further include means for transmitting at least a portion of the first part of the second data unit to a network device in the first data unit.

[0103] In some exemplary embodiments, an apparatus capable of performing Method 400 (e.g., a network device 110) may include means for performing each step of Method 400. These means can be implemented in any preferred form. For example, the means may be implemented in a circuit or a software module.

[0104] In some exemplary embodiments, the apparatus includes means for receiving a random access request from a terminal device in a random access procedure, and means for transmitting an uplink grant of the terminal device indicating the first size of the first data unit to the terminal device, so that the terminal device determines whether the first size of the first data matches the second size of the second data unit stored in the terminal device's buffer, in response to receiving the random access request.

[0105] In some exemplary embodiments, means for receiving random access requests may include means for receiving one of a non-conflict random access preamble and a conflict-based random access preamble.

[0106] In some exemplary embodiments, the second data unit may comprise at least one of the following MAC CEs: C-RNTI, BSR, and PHR.

[0107] In some exemplary embodiments, the BSR may comprise at least one of a shortened BSR, a padding BSR, a normal BSR, and a periodic BSR.

[0108] In some exemplary embodiments, the device further includes means for receiving at least a portion of the first part of the second data unit from a terminal device in the first data unit.

[0109] Figure 5 is a simplified block diagram of a device 500 suitable for carrying out exemplary embodiments of the present disclosure. Device 500 may be considered a further exemplary embodiment of the terminal device 120 shown in Figure 1. Thus, device 500 may be implemented in or as at least part of the terminal device 120.

[0110] As shown, device 500 includes a processor 510, a memory 520 connected to the processor 510, a suitable transmitter (TX) and receiver (RX) 540 connected to the processor 510, and a communication interface connected to the TX / RX 540. The memory 520 stores at least a portion of the program 530. The TX / RX 540 is for bidirectional communication. The TX / RX 540 has at least one antenna to facilitate communication, although in practice, the access node referred to in this application may have multiple antennas. The communication interface may represent any interface necessary for communication with other network elements, such as an X2 interface for bidirectional communication between eNBs, an S1 interface for communication between a mobility management entity (MME) / serving gateway (S-GW) and an eNB, an Un interface for communication between an eNB and a relay node (RN), or a Uu interface for communication between an eNB and a terminal device.

[0111] The program 530 is assumed to include program instructions, which, when executed by the associated processor 510, enable the device 500 to operate according to exemplary embodiments of the disclosure, as discussed herein with reference to Figures 2-4. These exemplary embodiments may be implemented by computer software, hardware, or a combination of software and hardware, executable by the processor 510 of the device 500. The processor 510 may be configured to implement various exemplary embodiments of the disclosure. Furthermore, a combination of the processor 510 and the memory 520 may form processing means 550 adapted to implement various exemplary embodiments of the disclosure.

[0112] Memory 520 can be any type suitable for a local technical network and may be implemented using any suitable data storage technology, including, but not limited to, non-temporary computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. Although only one memory 520 is shown for device 500, device 500 may have several physically separate memory modules. Processor 510 can be any type suitable for a local technical network and may include, but not limited to, one or more processors based on a general-purpose computer, a dedicated computer, a microprocessor, a digital signal processor (DSP), and a multi-core processor architecture. Device 500 may have multiple processors, such as application-specific integrated circuit chips configured to time-track a clock that synchronizes the main processor.

[0113] Typically, various embodiments of the present disclosure may be implemented in hardware, dedicated circuitry, software, logic, or any combination thereof. Some embodiments may be implemented in hardware, while others may be implemented in firmware or software that can run on a controller, microprocessor, or other computing device. Various embodiments of the present disclosure are illustrated and described using block diagrams, flowcharts, or other graphical representations, but it will be understood that any blocks, apparatus, systems, techniques, or methods described herein may be implemented, in non-limiting examples, in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or any combination thereof.

[0114] This disclosure also provides at least one computer program product substantially stored in a non-temporary computer-readable storage medium. The computer program product includes computer-executable instructions, which, for example, are contained in a program module and are executed on a device on a target real or virtual processor to perform the processes or methods described above with reference to any of Figures 2 to 5. Typically, a program module includes routines, programs, libraries, objects, classes, components, or data structures that perform a particular task or implement a particular abstract data type. The functionality of the program modules may be combined or separated amongst the program modules as desired in various embodiments. The machine-executable instructions of the program modules may be executed in a local device or a distributed device. In a distributed device, the program modules may reside in both local and remote storage media.

[0115] Program code for performing the methods of this 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, a dedicated computer, or other programmable data processing device, thereby causing the program code, when executed by the processor or controller, to perform functions / operations specified in flowcharts and / or block diagrams. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or remote server.

[0116] In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals and computer-readable media.

[0117] Computer-readable media may be computer-readable signal media or computer-readable storage media. Computer-readable media may include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any preferred combination thereof. More specific examples of computer-readable storage media include electrical connections with one or more wires, portable computer diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any preferred combination thereof.

[0118] Furthermore, although the operations are described in a specific order, this should not be understood as meaning that such operations must be performed in a specific order or sequence shown, or that all the operations exemplified must be performed, in order to obtain the desired results. In certain circumstances, multitasking and parallel processing may be advantageous. Similarly, the above discussion includes details of several specific embodiments, but these should not be interpreted as limitations on the scope of this disclosure, but rather as descriptions of features that may be specific to a particular embodiment. Certain features described in the context of a separate embodiment may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any preferred partial combination in multiple embodiments.

[0119] While this disclosure is described in language specific to structural features and / or methodological actions, it should be understood that the disclosure as defined in the attached claims is not necessarily limited to the specific features or actions described herein. Rather, the specific features and actions described herein are disclosed as exemplary forms for implementing the claims.

Claims

1. A method performed on a terminal device, In a terminal device, a random access request is sent to a network device using a random access procedure, In the random access procedure, upon receiving an uplink grant from the network device to the terminal device, it is determined whether the first size of the first data unit indicated by the uplink grant matches the second size of the second data unit stored in the buffer of the terminal device. In response to determining that the first size does not match the second size, the first portion of the second data unit is determined for subsequent transmission. The method comprising the above.

2. Sending the aforementioned random access request means A race-free random access preamble and Competition-based random access preamble and The method according to claim 1, comprising transmitting one of the following.

3. The second data unit is a media access control MAC control element MAC CE. Cell radio network temporary identifier C-RNTI and Buffer Status Report BSR and Power Headroom Report (PHR) and The method according to claim 1, comprising at least one of the following.

4. The aforementioned BSR is Shortened BSR and Padding BSR and, Regular BSR and Periodic BSR and The method according to claim 3, comprising at least one of the following.

5. Determining the first part above means In response to determining that the second size does not match the first size, Discarding the shortened BSR from the second data unit, Discarding the padding BSR from the second data unit, Discarding the regular BSR from the second data unit, Discarding periodic BSR from the second data unit, Discarding the PHR from the second data unit, Adjusting the size of the shortened BSR, The method according to claim 1, comprising performing at least one of the following.

6. Determining the first part above means In response to determining that the second size does not match the first size, The random access procedure is determined by receiving the uplink grant, In determining that the random access procedure has been successfully completed, the C-RNTI media access control MAC control element MAC CE is discarded from the second data unit, The method according to claim 1, comprising:

7. Determining whether the aforementioned random access procedure has completed successfully is: The aforementioned uplink grant, Cell radio network temporary identifier C-RNTI and Random Access Wireless Network Temporary Identifier RA-RNTI, The method according to claim 6, further comprising determining that it is addressed to at least one of the following.

8. The subsequent transmission mentioned above is The transmission associated with the aforementioned uplink grant, A transmission associated with a further uplink grant different from the aforementioned uplink grant, The method according to claim 1, comprising at least one of the following.

9. To transmit at least a portion of the first part of the second data unit to the network device using the first data unit, The method according to claim 1, further comprising:

10. A method implemented in a network device, Receiving random access requests from terminal devices using a random access procedure, In response to receiving the random access request, the terminal device is sent an uplink grant for the terminal device indicating the first size of the first data unit, so that the terminal device can determine whether the first size of the first data unit matches the second size of the second data unit stored in the terminal device's buffer. The method comprising the above.

11. Receiving the aforementioned random access request means A race-free random access preamble and Competition-based random access preamble and The method according to claim 10, comprising receiving one of the following.

12. The second data unit is a media access control MAC control element CE. Cell radio network temporary identifier C-RNTI and Buffer Status Report BSR and Power Headroom Report (PHR) and The method according to claim 10, comprising at least one of the following.

13. The aforementioned BSR is Shortened BSR and Padding BSR and, Regular BSR and Periodic BSR and The method according to claim 12, comprising at least one of the following.

14. The terminal device receives at least a portion of the first part of the second data unit with the first data unit. The method according to claim 10, further comprising:

15. At least one processor, At least one memory containing computer program code, A terminal device equipped with, The at least one memory and the computer program code, together with the at least one processor, are provided to the terminal device at least In a terminal device, a random access request is sent to a network device using a random access procedure, In the random access procedure, upon receiving an uplink grant from the network device to the terminal device, it is determined whether the first size of the first data unit indicated by the uplink grant matches the second size of the second data unit stored in the buffer of the terminal device. In response to determining that the first size does not match the second size, the first portion of the second data unit is determined for subsequent transmission. The terminal device is configured to perform the following actions.

16. The aforementioned terminal device is A race-free random access preamble and Competition-based random access preamble and The device according to claim 15, which is triggered to transmit the random access request by transmitting one of the following.

17. The second data unit is a media access control MAC control element CE. Cell radio network temporary identifier C-RNTI and Buffer Status Report BSR and Power Headroom Report (PHR) and The device according to claim 15, comprising at least one of the following.

18. The aforementioned BSR is Shortened BSR and Padding BSR and, Regular BSR and Periodic BSR and The device according to claim 17, comprising at least one of the following.

19. The aforementioned terminal device is In response to determining that the second size does not match the first size, Discarding the shortened BSR from the second data unit, Discarding the padding BSR from the second data unit, Discarding the regular BSR from the second data unit, Discarding periodic BSR from the second data unit, Discarding the PHR from the second data unit, Adjusting the size of the shortened BSR, The device according to claim 15, which is caused to determine the first part by performing at least one of the following.

20. The aforementioned terminal device is In response to determining that the second size exceeds the first size, The random access procedure is determined by receiving the uplink grant, In determining that the random access procedure has been successfully completed, the C-RNTI media access control MAC control element CE is discarded from the second data unit, The device according to claim 15, which is caused to determine the first part by performing the following.

21. The aforementioned terminal device is The aforementioned uplink grant, Cell radio network temporary identifier C-RNTI and Random Access Wireless Network Temporary Identifier RA-RNTI, The device according to claim 15, which is triggered to determine whether the random access procedure has been successfully completed by determining that it is addressed to at least one of the following.

22. The subsequent transmission mentioned above is The transmission associated with the aforementioned uplink grant, A transmission associated with a further uplink grant different from the aforementioned uplink grant, The device according to claim 15, comprising at least one of the following.

23. The aforementioned terminal device further, To transmit at least a portion of the first part of the second data unit to the network device using the first data unit, The device according to claim 15, which is caused to perform the following action.

24. At least one processor, At least one memory containing computer program code, A network device equipped with, The at least one memory and the computer program code, together with the at least one processor, are provided to the network device at least Receiving random access requests from terminal devices using a random access procedure, In response to receiving the random access request, the terminal device is sent an uplink grant for the terminal device indicating the first size of the first data unit, so that the terminal device can determine whether the first size of the first data unit matches the second size of the second data unit stored in the terminal device's buffer. The network device is configured to perform the following actions.

25. The aforementioned network device A race-free random access preamble and Competition-based random access preamble and The device according to claim 24, which is triggered to receive the random access request by receiving one of the following.

26. The second data unit is a media access control MAC control element CE. Cell radio network temporary identifier C-RNTI and Buffer Status Report BSR and Power Headroom Report (PHR) and The device according to claim 24, comprising at least one of the following.

27. The aforementioned BSR is Shortened BSR and Padding BSR and, Regular BSR and Periodic BSR and The device according to claim 24, comprising at least one of the following.

28. The aforementioned network device further, The terminal device receives at least a portion of the first part of the second data unit with the first data unit. The device according to claim 24, which is caused to perform the following:

29. A device for random access procedures, A terminal device provides a means for sending a random access request to a network device using a random access procedure, The random access procedure includes means for determining whether the first size of the first data unit indicated by the uplink grant matches the second size of the second data unit stored in the buffer of the terminal device, in response to receiving an uplink grant from the network device of the terminal device. In response to determining that the first size does not match the second size, means for determining the first portion of the second data unit for subsequent transmission, The apparatus comprising the above.

30. A device for random access procedures, A means for receiving random access requests from a terminal device using a random access procedure, Means for transmitting an uplink grant of the terminal device indicating the first size of the first data unit to the terminal device, so that the terminal device determines whether the first size of the first data matches the second size of the second data unit stored in the buffer of the terminal device in response to receiving the random access request, The apparatus comprising the above.

31. A non-temporary computer-readable medium comprising program instructions for causing a device to perform at least one of the methods described in claims 1 to 9.

32. A non-temporary computer-readable medium comprising program instructions for causing a device to perform the method according to at least one of claims 10 to 14.

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