WO2021093211A1

WO2021093211A1 - Methods and systems for scheduling uplink data transmissions in wireless communication networks

Info

Publication number: WO2021093211A1
Application number: PCT/CN2020/075543
Authority: WO
Inventors: Xincai LI; Li Tian
Original assignee: Zte Corporation
Priority date: 2020-02-17
Filing date: 2020-02-17
Publication date: 2021-05-20
Also published as: CN114731621A

Abstract

Methods and systems for scheduling an uplink data transmission in wireless communication networks are disclosed herein. In one embodiment, a method performed by a first wireless communication node includes: transmitting a first downlink control message to a wireless communication device; initiating a first channel access procedure for accessing a predetermined channel for receiving scheduled UL data from the wireless communication device; determining whether the first channel access procedure is successfully completed prior to a predetermined event; and when the first channel access procedure is completed prior to the predetermined event, transmitting a notification message to the wireless communication device that notifies the wireless communication device that the wireless communication node has successfully completed the first channel access procedure, wherein the notification message triggers the wireless communication device to transmit the scheduled UL data on the predetermined channel based on a specified timing provided by the wireless communication node.

Description

[Rectified under Rule 91, 03.03.2020] METHODS AND SYSTEMS FOR SCHEDULING UPLINK DATA TRANSMISSION IN WIRELESS COMMUNICATION NETWORKS

TECHNICAL FIELD

The disclosure relates generally to wireless communications and, more particularly, to methods and systems for scheduling uplink data transmissions in wireless communication networks.

BACKGROUND

With the emergence of fifth-generation (5G) new radio (NR) networks will come an explosion of new user data applications that will be supported by the NR networks. With this rapid growth of user data, the demand for spectrum will increase dramatically. Previous solutions addressing existing and emerging user data traffic demands increased data rates by widening frequency channels or densifying base station (BS) deployments. For example, channel bandwidth increased from 200 kHz in 2G Global System for Mobile Communications (GSM) to 5 MHz in 3G Wideband Code Division Multiple Access (WCDMA) and 20 MHz in 4G Long Term Evolution (LTE) to 100 MHz in LTE-Advanced Pro. However, the conventional sub-6 GHz frequency spectrum is almost fully allocated and expensive for system operators to license. Moreover, further network densification is limited by the cost and time needed to acquire backhaul connections and siting permits in millions of local jurisdictions.

Using unlicensed carrier frequencies (a.k.a., unlicensed spectrum) to transmit data can increase the utilization rate of available transmission resources. One possible utilization of unlicensed spectrum is to support ultra reliable low-latency communications (URLLC) . According to the regulatory requirements for unlicensed operation, however, a device is required to successfully perform a Clear Channel Assessment (CCA) procedure (a.k.a., Listen Before Talk (LBT) ) , and have a successful result prior to data transmission. Thus, when using unlicensed carriers, 5G NR systems need to address various issues. Additionally, in some countries and regions, there are regulatory policies for the use of unlicensed spectrum.

Currently, two types of CCA mechanisms are standardized, which must be successfully completed before uplink transmission can be performed by a device. The first type is referred to as “type-1 CCA, ” which implements a random back-off procedure and is configured for multiple access priority classes for different channels. The second type is referred to as “type-2 CCA, ” which does not include a random fallback procedure and performs carrier sensing for a predefined duration. Generally, type-2 CCA requires less time to complete compared to type-1 CCA and, therefore, reduces transmission latency times. In most cases, data transmissions by a User Equipment device (UE) , including transmissions scheduled by a base station and autonomous uplink transmissions (e.g., grant-free transmission or configured grant transmission) require a similar channel access procedure to be successfully completed prior to uplink transmissions.

To improve the efficiency of data transmissions, new channel access procedures and control signaling protocols need to be considered. It would be advantageous if a communication system can support fast and reliable data transmissions when using unlicensed carriers for transmitting URLLC uplink data. For scheduled UL transmissions, according to the existing methods and schemes, only the UE that will transmit data performs a CCA procedure. If the UE cannot perform CCA successfully before the time of a scheduled a physical uplink shared channel (PUSCH) transmission, the UE’s uplink data is dropped and rescheduled again, which adversely impacts URLLC performance and increases data transmission latency. Thus, existing methods of scheduling UL transmissions are not entirely satisfactory.

SUMMARY OF THE INVENTION

The exemplary embodiments disclosed herein are directed to solving the issues relating to one or more of the problems presented in the prior art, as well as providing additional features that will become readily apparent by reference to the following detailed description when taken in conjunction with the accompany drawings. In accordance with various embodiments, exemplary systems, methods, devices and computer program products are disclosed herein. It is understood, however, that these embodiments are presented by way of example and not limitation, and it will be apparent to those of ordinary skill in the art who read the present disclosure that various modifications to the disclosed embodiments can be made while remaining within the scope of the present disclosure.

In one embodiment, a method of scheduling uplink (UL) data transmissions performed by wireless communication node, includes: transmitting a first downlink control message to a wireless communication device; initiating a first channel access procedure for accessing a predetermined channel for receiving scheduled UL data from the wireless communication device; determining whether the first channel access procedure is successfully completed prior to a predetermined event; and when the first channel access procedure is completed prior to the predetermined event, transmitting a notification message to the wireless communication device that notifies the wireless communication device that the wireless communication node has successfully completed the first channel access procedure, wherein the notification message triggers the wireless communication device to transmit the scheduled UL data on the predetermined channel based on a specified timing provided by the wireless communication node.

In another embodiment, a method of scheduling uplink (UL) data transmissions performed by wireless communication device, includes: receiving a first downlink control message from a wireless communication node; initiating a first channel access procedure for accessing a predetermined channel for transmitting scheduled UL data; determining whether the first channel access procedure is successfully completed prior to a predetermined event; when the first channel access procedure is completed prior to the predetermined event, transmitting the scheduled UL data in accordance with first timing information contained in the first downlink control message; and when the first channel access procedure is not completed prior to the predetermined event, transmitting the scheduled UL data in accordance with second timing information provided by the wireless communication node.

In another embodiment, a wireless communication node, includes: a transceiver configured to transmit a first downlink control message to a wireless communication device; and at least one processor configured to: initiate a first channel access procedure for accessing a predetermined channel for receiving scheduled UL data from the wireless communication device; and determine whether the first channel access procedure is successfully completed prior to a predetermined event, wherein when the first channel access procedure is completed prior to the predetermined event, the transceiver is further configured to transmit a notification message to the wireless communication device that notifies the wireless communication device that the wireless communication node has successfully completed the first channel access procedure, and wherein the notification message triggers the wireless communication device to transmit the scheduled UL data on the predetermined channel based on a specified timing provided by the wireless communication node.

In a further embodiment, a wireless communication device, includes: a transceiver configured to receive a first downlink control message from a wireless communication node; and at least one processor configured to: initiate a first channel access procedure for accessing to a predetermined channel for transmitting scheduled UL data; and determine whether the first channel access procedure is successfully completed prior to a predetermined event, wherein when the first channel access procedure is completed prior to the predetermined event, the transceiver is further configured to transmit the scheduled UL data in accordance with first timing information contained in the first downlink control message, and wherein when the first channel access procedure is not completed prior to the predetermined event, the transceiver is further configured to transmit the scheduled UL data in accordance with second timing information provided by the wireless communication node.

In further embodiments, the invention provides a non-transitory computer-readable storage medium storing computer-executable instructions that when executed perform any one of the methods disclosed herein.

In yet further embodiments, a wireless communication node includes a memory storing computer-executable instructions that when executed perform any one of the methods disclosed herein; and at least one processor, coupled to the memory, and configured to execute the computer-executable instructions.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of the present disclosure are described in detail below with reference to the following Figures. The drawings are provided for purposes of illustration only and merely depict exemplary embodiments of the present disclosure to facilitate the reader's understanding of the present disclosure. Therefore, the drawings should not be considered limiting of the breadth, scope, or applicability of the present disclosure. It should be noted that for clarity and ease of illustration these drawings are not necessarily drawn to scale.

Figure 1 illustrates a block diagram of an exemplary communications network in which the techniques and methods disclosed herein may be implemented, in accordance with some embodiments of the invention.

Figure 2 illustrates a flow chart of an exemplary process of scheduling uplink transmissions, in accordance with some embodiments of the invention.

Figure 3 illustrates a timing diagram of an exemplary scenario for scheduling uplink transmissions in which the UE successfully completes a CCA process before the BS successfully completes a CCA process, in accordance with some embodiments of the invention.

Figure 4 illustrates a timing diagram of an exemplary scenario for scheduling uplink transmissions in which the BS successfully completes a CCA process before the UE successfully completes a CCA process, in accordance with some embodiments of the invention.

Figure 5 illustrates a timing diagram of an exemplary scenario for scheduling uplink transmissions in which the BS achieves CCA success later than a starting point indicated for a scheduled PUSCH transmission, in accordance with some embodiments of the invention.

Figure 6 illustrates a timing diagram of an exemplary scenario for one-shot triggered UL transmission for multiple UL transmissions, in accordance with some embodiments of the invention.

Figure 7 illustrates a block diagram of a wireless communication node configured to perform the methods disclosed herein, in accordance with various embodiments of the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Various exemplary embodiments of the present disclosure are described below with reference to the accompanying figures to enable a person of ordinary skill in the art to make and use the present disclosure. As would be apparent to those of ordinary skill in the art, after reading the present disclosure, various changes or modifications to the examples described herein can be made without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, the specific order and/or hierarchy of steps in the methods disclosed herein are merely exemplary approaches. Based upon design preferences, the specific order or hierarchy of steps of the disclosed methods or processes can be re-arranged while remaining within the scope of the present disclosure. Thus, those of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or acts in a sample order, and the present disclosure is not limited to the specific order or hierarchy presented unless expressly stated otherwise.

As discussed herein, a “wireless communication node” can include, or be implemented as a Base Station (BS) , a next Generation Node B (gNB) , an E-UTRAN Node B (eNB) , a Transmission Reception Point (TRP) , an Access Point (AP) , a donor node (DN) , a relay node, a core network (CN) node, a RAN node, a master node, a secondary node, a distributed unit (DU) , a centralized unit (CU) , etc., in accordance with the customary understanding of these terms in the art. Furthermore, as discussed herein, a “wireless communication device” can include, or be implemented as a UE, a station (STA) , a mobile terminal (MT) , mobile station (MS) , etc., in accordance with the customary understanding of these terms in the art. In the description of exemplary embodiments below, a BS is described as an exemplary embodiment of a “wireless communication node” and a UE is described as an exemplary embodiment of a “wireless communication device. ” It should be understood, however, that the scope of the present disclosure is not limited to these exemplary embodiments.

FIG. 1 illustrates an exemplary communication network 100 in which techniques disclosed herein may be implemented, in accordance with an embodiment of the present disclosure. As shown in FIG. 1, the exemplary communication network 100 includes a first base station (BS1) 110 and a second base station (BS2) 120. BS1 110 supports communications within a first cell area 101 within which a plurality of UEs, UE1 111 …UE2 112, are located and wherein the BS1 110 can communicate with these UEs according to various wireless communication protocols. Similarly, BS2 120 supports communications in a second cell area 102 in which a plurality of UEs, UE2 112, UE3 123 …UE4 124, are located, and wherein BS2 120 can communicate with these UEs according to various wireless communication protocols. As shown in Figure 1, the UE 2 112 is within the cell coverage areas of both the first and

second cell areas

101 and 102, respectively. Thus, the UE2 can be connected to both BS1 110 and BS2 120 simultaneously (i.e., dual connectivity (DC) ) or connected to only one of them depending on various wireless communication protocols and/or techniques.

Before a UE can initiate an uplink transmission to its associated BS, a channel access procedure must be successfully completed so that communication resources can be allocated to the UE prior to the uplink transmission. To improve the probability of completing a channel access procedure and improving the efficiency of the uplink data transmission protocol, one or more downlink control information (DCI) messages are transmitted to the UE, in accordance with some embodiments.

In a first embodiment, after the base station (BS) sends an uplink (UL) grant containing a first downlink control information (DCI1) message to the UE, both the BS and the UE will perform a channel access procedure (e.g., LBT) to access a channel for subsequent data communications between the BS and the UE. In accordance with some embodiments, the first DCI contains two sets of time domain resource allocation (TDRA) fields. A first set of TDRA fields (TDRA1) is used to determine the time domain resources for data transmission if the UE successfully completes the channel access procedure first. A second set of TDRA fields (TDRA2) is used to determine the time domain resources for data transmission if the BS successfully completes the channel access procedure first, prior to the UE. Thus, the UE can prepare the UL data after receiving the first UL grant, and then determine which set of TDRA fields to use to prepare and send the UL transmission (e.g., a physical uplink shared channel (PUSCH) transmission) at the corresponding time, depending on whether the UE or the BS successfully completes the channel access procedure first.

Thus, in some embodiments, if the UE wins the competition, the UE determines a time domain position for transmission of the PUSCH based on the TDRA1 fields contained in the first DCI. In some embodiments, the TDRA1 fields contains the same information as conventional TDRA messages. On the other hand, if the BS wins the competition, the TDRA2 fields, or at least a portion thereof, are used to determine channel resources for subsequent communications between the BS and the UE.

In some embodiments, the first DCI (DCI1) contains both the TDRA1 and TDRA2 fields described above. In this case, when the UE wins the competition, it will transmit the PUSCH data in accordance with the information contained in the TDRA1 fields provided by DCI1. On the other hand, when the BS wins the competition, the BS simply notifies the UE that it has successfully completed its channel access via a conventional DCI 2_0 procedure, or the predefined sequence, which can be detected by the UE while performing its CCA procedure. Thereafter, the UE can transmit data via the PUSCH in accordance with the information contained in the TDRA2 fields contained in DCI1, without receiving further control information (e.g., a second DCI (DCI2) ) from the BS.

In some embodiments, when DCI1 contains both the TDRA1 and TDRA2 fields, the TDRA1 field will be the same as conventional TDRA information. In this case, the TDRA2 fields includes two parts. In some embodiments, the first part includes two bits that indicate a time period after which the first UL grant becomes invalid. In some embodiments, the first UL grant becomes invalid if M milliseconds (ms) after the first UL grant, no triggering DCI or predefined sequence has been received by the UE. In some embodiments, the M value can indicate a number of symbols. In some embodiments, the second part includes two bits that indicate a timing or offset value relative to the triggering event (e.g., a predefined sequence or DCI2) for transmitting the PUSCH by the UE. In some embodiments, this offset value can indicate a number of OFDM symbols (e.g., {2, 4, 8, 12, 14 OFDM symbols} ) after transmission of the triggering DCI.

In alternative embodiments, the first UL grant containing the first DCI is not modified and contains only conventional TDRA information that is used for the time domain resource allocation when the UE competes successfully for the resources. However, in this case, when the BS achieves CCA success before the UE, the BS sends a second UL grant containing a second DCI message (DCI2) to notify the UE of the timing to transmit data via the PUSCH. In some embodiments, the DCI2 message contains only the second part described above, e.g., an offset value relative to a time when the second DCI is transmitted that informs the UE when to transmit the scheduled UL data on the predetermined PUSCH.

Figure 2 illustrates a flow chart of a process 200 for scheduling UL transmissions, in accordance with some embodiments of the invention. At step 201, the BS (e.g, a gNB) sends one or more DCI messages to the UE. In some embodiments, the BS only sends a first DCI message containing conventional DCI information that is used when the UE successfully completes a channel access procedure before the BS. In this case, when the BS sends only the first DCI message and the BS wins the competition, the BS will thereafter send a second UL grant containing a second DCI message to the BS. In some embodiments, the second DCI message contains only the second part of the TDRA2 fields, as discussed above.

In alternative embodiments, at step 201, the BS sends both the TDRA1 and TDRA2 fields in the first DCI message, which can be considered a “modified DCI message, ” in the first UL grant. If the UE wins the competition (e.g., the UE has achieved CCA success before detecting any DMRS sequence or group-common DCI that informs the UE of BS CCA success) , the TDRA1 fields are used to allocate resources for subsequent communications (e.g., PUSCH) between the US and BS. On the other hand, if the BS wins the competition, the TDRA2 fields are used to allocate resources for subsequent communications between the BS and UE. Thus, in this embodiment, a second UL grant (e.g., a PDCCH signal) containing a second DCI is not necessary before the UE can initiate a PUSCH transmission via the allocated resources. In some embodiments, when the first DCI contains both the first and second sets of TDRA fields, as described above, if the BS achieves CCA success earlier than the UE, the BS will simply transmit a predefined sequence to the UE to notify the UE that the BS has achieved CCA success. After receiving such notification, the UE will then transmit its PUSCH data in accordance with information contained in the TDRA2 fields provided by the first DCI.

Next, at step 203, both the BS and the UE begin to perform a CCA procedure. At step 205, it is determined whether the UE has successfully completed a CCA procedure. If UE achieves CCA success before the BS achieves CCA success, then at step 207, the UE will transmit data in accordance with the TDRA1 parameters contained in DCI1.

At step 209, it is determined whether the BS has successfully completed a CCA procedure. If the BS achieves CCA success before the UE, then at step 211, the BS transmits either a second UL grant via the PDCCH, or a predefined sequence. In some embodiments, if DCI1 contained only the TDRA1 fields at step 201, then at step 211, the BS transmits a second DCI (DCI2) containing the TDRA2 fields, or a portion thereof. On the other hand, if the first DCI contained both the TDRA1 and TDRA2 fields at step 201, then at step 211, the BS transmits a predefined sequence to inform the UE that the BS has successfully completed the CCA procedure. In accordance with various embodiments, the predefined sequence may include a dedicated demodulation reference signal (DMRS) , a synchronization signal block (SSB) , a channel state information reference signal (CSI-RS) , a pseudo-random number (PN) or a Zadoff-Chu (ZC) sequence.

At step 213, the UE transmits the PUSCH data in accordance with the TDRA2 field parameters contained in either the first DCI or the second DCI. In some embodiments, DCI2 contains only an offset value relative to a position or time when the DCI2 signal was transmitted. In this case, the UE transmits the PUSCH data in accordance with a slot position and starting symbol indicated by the DCI2 parameters subsequent to successful CCA completion by the BS.

As discussed above, in some embodiments, both TDRA1 and TDRA2 can be contained in the first DCI message (DCI1) , in which case the BS does not need to send a second DCI message (DCI2) after successful completion of CCA. In this case, the BS need only send a predefined sequence to notify the UE of the BS’s successful CCA. On the other hand, in alternative embodiments, only TDRA1 is contained in DCI1. In some embodiments, TDRA1 contains conventional TDRA information. In this case, at least a portion of TDRA2 must be subsequently transmitted by the BS in a second DCI (DCI2) if the BS achieves CCA success before the UE achieves CCA success. In some embodiments, DCI2 contains only the second part (e.g., the offset value) without containing the first part (e.g., expiration period for first UL grant) , since the first part may not be necessary in this scenario.

As also discussed above, in various embodiments, with the help of the BS performing CCA, the UL transmission probability can be improved, especially when the UE is configured to perform type-1 CCA. In some embodiments, if the BS achieves CCA success first, then the UE is configured to perform type-2 CCA, which improves the UE’s CCA success probability, thereby improving reliability and decreasing latency of URLLC transmissions by the UE, for example.

In some embodiments, when the UE achieves CCA success for a scheduled uplink data transmission, for a single transmission time interval (TTI) or PUSCH scheduling, the DCI is in “format 0_1. ” In this case, the UE first receives the DCI from the BS, and then performs CCA. After a successful CCA process, the UE sends the data based on the indication in the DCI. In some embodiments, the DCI for scheduling the PUSCH includes at least one of the following type of information: type of channel access, priority of channel access, time domain allocation information (including one or more starting and ending points or lengths of scheduled data transmission) , carrier indication information, bandwidth part (BWP) index information, frequency domain resource allocation information, hybrid automatic repeat request (HARQ) procedure number information, new data indicator (NDI) information, redundancy version (RV) information, code block group transmission information (CBGTI) , demodulation reference signal (DMRS) information, phase tracking reference signal (PTRS) information, channel state information (CSI) feedback request information, sounding reference signal (SRS) request information, modulation coding scheme (MCS) information, scheduled TTI or PUSCH number, etc.

Figure 3 illustrates a timing diagram of an exemplary scenario in which a UE successfully completes a CCA process before the BS completes a CCA process, in accordance with some embodiments. At time t0, the BS begins transmitting a first DCI message. In some embodiments, the first DCI message includes timing information (e.g., K2=1) , which indicates a number of slots between completion of DCI transmission and subsequent transmission of the PUSCH by the UE. In some embodiments, K2=1 indicates that the number of slots is 1. At time t1, the transmission of the first DCI is completed and the BS begins performing a channel access procedure (e.g., CCA) but does not successfully complete CCA prior to the UE completing its CCA, as indicated in Figure 3. At time t2, after receiving the first DCI, the UE begins performing its designated channel access procedure. At time t3, the UE has successfully completed its channel access procedure and accessed a channel without detecting that the BS has successfully completed its channel access procedure (e.g., no PDCCH or other predefined sequence is detected indicating the channel for PUSCH transmission is occupied by the BS) . Immediately, after completing the CCA process, at time t3, the UE transmits data on the PUSCH in accordance with the received first DCI.

Figure 4 illustrates a timing diagram of another exemplary scenario in which the BS achieves CCA success earlier than the UE, in accordance with some embodiments. In this case, at time t0, the BS transmits a first DCI containing timing information (e.g., K2=0100 in binary or 4 in decimal) . In some embodiments, this first DCI contains both TDRA1 and TDRA2 information. In alternative embodiments, the first DCI contains only TDRA1 information, and a subsequently transmitted second DCI contains at least a portion of the TDRA2 information, which is transmitted by the BS if the BS achieves CCA success before the UE, as illustrated in Figure 4.

As discussed above, when DCI1 contains both TDRA1 and TDRA2 information, the TDRA2 information includes two parts, in accordance with some embodiments. A first part includes two bits indicating a number of slots after DCI transmission, after which the first UL grant becomes invalid. In some embodiments, the initial UL grant becomes invalid if M ms after the initial grant, no valid trigger event (e.g., DCI or predefined sequence) has been received, where M is a predetermined positive integer. In other embodiments, the M value can indicate a number of symbols after DCI transmission after which the initial UL grant becomes invalid. A second part of the TDRA2 information includes another two bits indicating a timing or offset value after a second DCI is transmitted by the BS (e.g., {2, 4, 8, 12, 14 OFDM symbols} ) for transmitting data via the PUSCH. In some embodiments, besides the TDRA information, other information _, that the UE used to prepare data can be included in the first DCI. Such other information can include, for example, frequency domain resource allocation information, hybrid automatic repeat request (HARQ) procedure number information, new data indicator (NDI) information, redundancy version (RV) information, code block group transmission information (CBGTI) , demodulation reference signal (DMRS) information, and modulation coding scheme (MCS) information. In some embodiments, CCA related information for the UE, such as CCA type and channel access priority class, for example, can also be included in the first DCI. On the other hand, when DCI1 contains only TDRA1 information, a second DCI (DCI2) will contain at least a portion of the TDRA2 information, as discussed above.

Referring again to Figure 4, at time t1, after transmitting the first DCI, the BS begins to perform a CCA process. Next, at time t2, the UE also begins performing a CCA process but is not successful, as shown in Figure 4. At time t3, the BS successfully completes the CCA process, and if the BS achieves CCA success within the valid time period indicated in the first part of TDRA2 (e.g., within 4 slots of first DCI transmission) , the BS transmits the second DCI or a predefined sequence via a PDCCH to inform the UE that the BS has achieved CCA success. In some embodiments, the second DCI can be a group common DCI, such as DCI format 2_0 or other DCI.

Upon receiving the second DCI or predefined sequence, the UE will know that the BS has achieved CCA success before it has achieved CCA success. Thereafter, at time t4 (which may be different from its originally scheduled transmission time) , the UE can send data via the PUSCH according to the timing indicated in the first DCI (if the first DCI is modified to contain both TDRA1 and TDRA2 information) , or the timing indicated in the second DCI (if the first DCI contains only TDRA1 information and the second DCI contains the TDRA2 information) . As discussed above, in some embodiments, the TDRA2 information includes at least two bits indicating a timing or offset value relative to a time the UE detected the predefined sequence (when first DCI is modified) or the second DCI (when first DCI is not modified) , for transmitting the PUSCH data. Thus, through the mechanisms and schemes described above, the PUSCH transmission latency can be reduced since the UE does not need to prepare another PUSCH or continue performing CCA after receiving the predefined sequence or second DCI from the BS.

Figure 5 illustrates a timing diagram of an exemplary scenario in which the BS achieves CCA success later than a starting point indicated for a UE CCA success and PUSCH transmission for a scheduled uplink data transmission, in accordance with some embodiments. At time t0, the BS transmits a first DCI containing timing information (e.g., K2 = 0100 in binary or 4 in decimal) . At time t1, the UE begins performing CCA but is not successful before a scheduled UL transmission at t2. At time t4, the BS achieves CCA success and transmits a PDCCH containing either a predefined sequence (when DCI1 is modified) or a second DCI to the UE. Thereafter, at time t5, the UE will transmit PUSCH data in accordance with the timing information contained in the first or second DCI, which can be earlier than waiting for a next scheduled PUSCH transmission by conventional methods. In this way, the PUSCH transmission latency can also be reduced since the UE does not need to prepare another PUSCH or continue performing CCA after receiving the predefined sequence or second DCI from the BS.

In some embodiments, the BS can assist the UE to perform CCA to reduce UL data transmission latency. For example, the BS can send a normal UL grant containing timer information for configuring the UE. The timer can be set for 2 ms, for example, which is started when the UE receives the first UL grant. After receiving the UL grant, the UE prepares the PUSCH according to the scheduling information contained in the UL grant. In some embodiments, if the UE receives a second UL grant containing either a second DCI or a predefined sequence, which informs the UE that the BS has achieved CCA success, the UE will determine whether to perform CCA or which type of CCA it should perform according to a DL-UL gap duration. In some embodiments, if the gap duration is less than 16 μs, for example, then UE can transmit the PUSCH directly. In some embodiments, if the gap duration is between 16us and 25 μs, the UE can perform a 16μs-type CCA and if it achieves CCA success, the UE can transmit PUSCH that is has prepared before. Additionally, in some embodiments, if the gap duration is greater than 25 μs, the UE will perform a 25μs-type CCA and if CCA success is achieved, the UE will transmit the PUSCH that is has prepared before.

In further embodiments, the BS can trigger the UE to perform a “one-shot scheduling mode, ” as described in further detail below. In some embodiments, the DCI may be a UE-specific DCI scrambled by a specific radio network temporary identifier (RNTI) . Alternatively, the transmission mode can be triggered by 1 bit in the UL grant, for example. In some embodiments, after detecting the DCI, the UE transmits all the data of a HARQ process that has not been successfully transmitted (including data that was not sent due to a failure of the originally scheduled LBT as well as data subject to maximum channel occupancy time (MCOT) restrictions (e.g., K2 = non-numerical) . In this case, the UE can send the data in accordance with an order based on: a previously scheduled sequence, a minimum control channel element (CCE) index, a starting position in the frequency domain, or a HARQ process number.

In some embodiments, a one-shot scheduling DCI can trigger the transmissions of multiple PUSCHs, because PUSCHs with previously failed CCA or scheduled PUSCHs that have not been transmitted cannot be combined and transmitted through one PUSCH. Therefore, some methods are needed to send these multiple PUSCHs via different resources, e.g., on different time domains and/or different frequency domains, etc. In some embodiments, the different resources and their allocation can be indicated in the second DCI. For example, in some embodiments, the order of the multiple PUSCH transmissions of the one-shot scheduling mode can be determined according to some predefined rules, e.g. based on the minimum CCE index or the scheduling order for the first scheduling, or the starting point of the frequency domain, or HARQ process number, for example. In some embodiments, the BS can trigger one UE for one-shot scheduling of multiple PUSCH transmissions through one DCI, as described below.

For example, a UE may be scheduled for one PUSCH or multiple PUSCH transmissions, but the UE can not perform CCA success before the starting position of the one PUSCH transmission or any PUSCH of the scheduled multiple PUSCHs. In this case, the BS can trigger the UE to retransmit the PUSCHs that could not be transmitted previously in accordance with a new timing relative to the transmission of a predefined sequence or second DCI, as described above, which can be earlier than a second scheduled transmission time for the one or more PUSCHs that could not be transmitted in an earlier scheduled transmission time. Thus, the latency of UL transmission is reduced.

As another example, the first DCI can schedule one PUSCH transmission by providing a timing value for indicating to the UE to wait for the next DCI message (i.e., the second DCI) having a numerical transmission timing indicator field to tell the UE when to transmit the PUSCH. In some embodiments, the second DCI may trigger transmission of stored PUSCHs or retransmitted PUSCHs for one or more PUSCH transmissions. In some embodiments, multiple pending PUSCHs of multiple HARQ process messages may be triggered and subsequently transmitted in continuous, consecutive transmission time intervals (TTIs) . In some embodiments, after the UE has prepared one or more PUSCHs according to the first DCI, the UE can store the PUSCH data until a later time. After detecting a triggering event such as a second DCI or a predefined sequence indicating the BS has achieved CCA success, the UE can then transmit the stored PUSCH data continuously.

In some embodiments, the DCI can be a UE-specific DCI with specific RNTI scrambling, or the transmission mode can be triggered by a bit in the UL grant. For example, after detecting the triggering DCI, the UE can transmit UL data or multiple PUSCHs according to a bit field in the triggering DCI, or according to some predefined rule. For example, in a DCI indicating a one shot scheduling mode, multiple TDRA can be included, that is each PUSCH is associated with a corresponding TDRA. Alternatively, in some embodiments, each PUSCH is associated with a separate start and length indication value (SLIV) and mapping type. In some embodiments, the number of triggered PUSCHs can be signaled by the number of valid SLIVs contained in a row of a TDRA table contained in the DCI.

Through the above signaling design, one DCI can be configured to trigger multiple PUSCHs transmission, and each PUSCH can transmit a different transport block (TB) . By this arrangement, the overhead for scheduling DCI is reduced and the probability and latency of uplink transmission is increased. In some embodiments, the BS may trigger one UE for one-shot scheduling of multiple UL transmissions through one or more DCIs. For example, the UE can be scheduled for one PUSCH or multiple PUSCH transmissions, but the UE can not perform CCA success before the starting position of the one PUSCH transmission or any PUSCH of the scheduled multiple PUSCHs. In this case, the BS can trigger the UE to retransmit the one or more PUSCHs in accordance with a timing that is before a second scheduled transmission time for the UE, as described above.

As another example, a first DCI may schedule one PUSCH transmission by providing a timing value for indicating to the UE to wait for the next downlink control message having a numerical transmission timing indicator field to tell the UE when to transmit the one or more previously prepared and/or stored PUSCHs. Thus, the DL control message (e.g., DCI1 or DCI2) may trigger transmission of one or more stored PUSCHs or retransmitted PUSCHs. In some embodiments, multiple pending PUSCHs of multiple HARQ process messages may be triggered and subsequently transmitted in continuous TTIs. Thus, in accordance with some embodiments, the UE can prepare one or more PUSCHs according to a first DCI and store the PUSCH data until a later time. After detecting a triggering event (e.g., a second DCI or predefined sequence) , the UE then transmit the one or more PUSCHs continuously in accordance with timing and/or resource allocation information contained the triggering DCI. In some embodiments, the DCI can be a UE-specific DCI with specific RNTI scrambling, or the transmission mode can be triggered by a bit in the UL grant. After the UE detects the DCI, the UE can transmit UL data on one or multiple PUSCHs according to an assigned bit field in the UE-specific DCI, or according to some predefined rule.

In some embodiments, in the one-shot scheduling DCI, multiple TDRAs can be included, each TDRA being allocated to one PUSCH of the multiple PUSCH’s , respectively. Alternatively, in some embodiments, each PUSCH has a separate SLIV and mapping type. In some embodiments, the number of triggered PUSCHs is signaled by the number of indicated valid SLIVs in a row of a TDRA table signaled in the DCI. Through such a signaling design, one DCI can be configured to trigger multiple PUSCH transmissions, and each PUSCH can transmit a different TB. By this arrangement, the overhead of the scheduling DCI is reduced and the probability and latency of uplink transmission is increased.

Figure 6 illustrates a timing diagram of an exemplary scenario implementing a one shot triggered transmission for multiple PUSCHs, in accordance with some embodiments. As shown in Figure 6, at time t0, the BS sends one or more DCIs to the UE. In this example, three PUSCHs (PUSCH1, PUSCH2 and PUSCH3) can be scheduled by one DCI or three different DCIs, containing timing values (e.g., K2 values) associated with each PUSCH. Based on these timing values, PUSCH1 is scheduled to be transmitted at time t1, PUSCH2 is scheduled to be transmitted at time t2, and PUSCH3 is scheduled to be transmitted at time t3. However, in this example, the UE cannot access the channel before the times indicated by the DCI (s) for each PUSCH transmission due to CCA failures. Then, at time t4, the BS will send a new DCI after it has achieved CCA success. The new DCI will contain timing information for transmitting the PUSCH1, PUSCH2 and PUSCH3 data previously prepared and stored by the UE. After the UE receives this new DCI/DCIs, the UE can transmit the data for PUSCH1, PUSCH2 and PUSCH3 according to the timing indicated in the TDRA (s) of the second DCI. In some embodiments, a single TDRA can indicate a timing value of t5 for transmitting the first PUSCH1, and the remaining PUSCHs are subsequently transmitted continuously at times t6 and t7.

In some embodiments, a symbol duration L of PUSCH1, PUSCH2 and PUSCH3 is the same as an indication contained in the first DCI. In some embodiments, a starting symbol may be different. In some embodiments, the PUSCH1, PUSCH2 and PUSCH3 transmissions are continuous. In further embodiments, the UE determine time resources or the transmission sequences for PUSCH1, PUSCH2 and PUSCH3 transmissions based on an indication contained in the first DCI. In some embodiments, PUSCH1, PUSCH2 and PUSCH3 are the latest three PUSCHs that the BS has not successfully detected.

In some embodiments, a time gap may be exist between the second DCI and a UL PUSCH transmission. In accordance with some embodiments, if the gap is 16us, the UE need not perform CCA and can transmit the one or more PUSCHs directly. Through this scheme the UL transmission latency can be reduced since the UE no longer needs to wait for multiple subsequent UL grants for triggering multiple PUSCH retransmissions, even when the UE fails to achieve CCA success after the initial DCI. In some embodiments, all the data of one or more HARQ processes that were not transmitted due to CCA failure and/or MCOT restrictions, for example, are transmitted in an expedited fashion. In some embodiments, the multiple PUSCHs are transmitted in an order corresponding to their previous scheduling and/or based on CCE index values and/or frequency domain starting positions and/or HARQ process number values.

Figure 7 illustrates a block diagram of a network node (NN) 700, in accordance with various embodiments of the invention. The NN 700 is an example of a wireless communication node that can be configured to implement the various methods and processes described herein. In some embodiments, the NN 700 may be wireless communication node such as base station (BS) , as described herein. In other embodiments, the NN 700 may be a wireless communication device such as a user equipment device (UE) , as described herein. As shown in Figure 7, the NN 700 includes a housing 740 containing a system clock 702, a processor 704, a memory 706, a transceiver 710 comprising a transmitter 712 and receiver 714, a power module 708, and a DCI module 720.

In this embodiment, the system clock 702 provides the timing signals to the processor 404 for controlling the timing of all operations of the NN 700. The processor 704 controls the general operation of the NN 700 and can include one or more processing circuits or modules such as a central processing unit (CPU) and/or any combination of general-purpose microprocessors, microcontrollers, digital signal processors (DSPs) , field programmable gate array (FPGAs) , programmable logic devices (PLDs) , controllers, state machines, gated logic, discrete hardware components, dedicated hardware finite state machines, or any other suitable circuits, devices and/or structures that can perform calculations or other manipulations of data.

The memory 706, which can include both read-only memory (ROM) and random access memory (RAM) , can provide instructions and data to the processor 704. A portion of the memory 706 can also include non-volatile random access memory (NVRAM) . The processor 704 typically performs logical and arithmetic operations based on program instructions stored within the memory 706. The instructions (a.k.a., software) stored in the memory 406 can be executed by the processor 704 to perform the methods described herein. The processor 404 and memory 706 together form a processing system that stores and executes software. As used herein, “software” means any type of instructions, whether referred to as software, firmware, middleware, microcode, etc. which can configure a machine or device to perform one or more desired functions or processes. Instructions can include code (e.g., in source code format, binary code format, executable code format, or any other suitable format of code) . The instructions, when executed by the one or more processors, cause the processing system to perform the various functions described herein.

The transceiver 710, which includes the transmitter 712 and receiver 714, allows the NN 700 to transmit and receive data to and from an external network node (e.g., an STA or AP) . An antenna 750 is typically attached to the housing 740 and electrically coupled to the transceiver 710. In various embodiments, the NN 700 includes (not shown) multiple transmitters, multiple receivers, and multiple transceivers. In some embodiments, the antenna 750 includes a multi-antenna array that can form a plurality of beams each of which points in a distinct direction in accordance with MIMO beamforming techniques.

The DCI module 720 may be implemented as part of the processor 704 programmed to perform the functions herein, or it may be a separate module implemented in hardware, firmware, software or a combination thereof. In some embodiments, the DCI module 720 is part of a BS and is configured to generate the first and/or second DCI messages as described herein. In some embodiments, the DCI module 720 is part of a UE and is configured to receive and process the first and/or second DCI messages as described herein. In accordance with various embodiments, the DCI module 720 can be implemented as software (i.e., computer executable instructions) stored in a non-transitory computer-readable medium that when executed by processor 704, transform the processor 704 into a special-purpose computer to perform the nulling operations described herein.

The various components and modules discussed above within housing 740 are coupled together by a bus system 730. The bus system 730 can include a data bus and, for example, a power bus, a control signal bus, and/or a status signal bus in addition to the data bus. It is understood that the modules of the NN 700 can be operatively coupled to one another using any suitable techniques and mediums. It is further understood that additional modules (not shown) may be included in the NN 700 without departing from the scope of the invention.

While various embodiments of the present disclosure have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. Likewise, the various diagrams may depict an example architectural or configuration, which are provided to enable persons of ordinary skill in the art to understand exemplary features and functions of the present disclosure. Such persons would understand, however, that the present disclosure is not restricted to the illustrated example architectures or configurations, but can be implemented using a variety of alternative architectures and configurations. Additionally, as would be understood by persons of ordinary skill in the art, one or more features of one embodiment can be combined with one or more features of another embodiment described herein. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments.

It is also understood that any reference to an element herein using a designation such as "first, " "second, " and so forth does not generally limit the quantity or order of those elements. Rather, these designations can be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements can be employed, or that the first element must precede the second element in some manner.

Additionally, a person having ordinary skill in the art would understand that information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits and symbols, for example, which may be referenced in the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

A person of ordinary skill in the art would further appreciate that any of the various illustrative logical blocks, modules, processors, means, circuits, methods and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two) , firmware, various forms of program or design code incorporating instructions (which can be referred to herein, for convenience, as "software" or a "software module) , or any combination of these techniques.

To clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware or software, or a combination of these techniques, depends upon the particular application and design constraints imposed on the overall system. Skilled artisans can implement the described functionality in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure. In accordance with various embodiments, a processor, device, component, circuit, structure, machine, module, etc. can be configured to perform one or more of the functions described herein. The term “configured to” or “configured for” as used herein with respect to a specified operation or function refers to a processor, device, component, circuit, structure, machine, module, signal, etc. that is physically constructed, programmed, arranged and/or formatted to perform the specified operation or function.

Furthermore, a person of ordinary skill in the art would understand that various illustrative logical blocks, modules, devices, components and circuits described herein can be implemented within or performed by an integrated circuit (IC) that can include a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logical blocks, modules, and circuits can further include antennas and/or transceivers to communicate with various components within the network or within the device. A processor programmed to perform the functions herein will become a specially programmed, or special-purpose processor, and can be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein.

If implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program or code from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

In this document, the term "module" as used herein, refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, for purpose of discussion, the various modules are described as discrete modules; however, as would be apparent to one of ordinary skill in the art, two or more modules may be combined to form a single module that performs the associated functions according embodiments of the present disclosure.

Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other implementations without departing from the scope of this disclosure. Thus, the disclosure is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as recited in the claims below.

Claims

A method of scheduling uplink (UL) data transmissions performed by wireless communication node, comprising:

transmitting a first downlink control message to a wireless communication device;

initiating a first channel access procedure for accessing a predetermined channel for receiving scheduled UL data from the wireless communication device;

determining whether the first channel access procedure is successfully completed prior to a predetermined event; and

when the first channel access procedure is completed prior to the predetermined event, transmitting a notification message to the wireless communication device that notifies the wireless communication device that the wireless communication node has successfully completed the first channel access procedure,

wherein the notification message triggers the wireless communication device to transmit the scheduled UL data on the predetermined channel based on a specified timing provided by the wireless communication node.
The method of claim 1, wherein the predetermined event comprises the wireless communication device successfully completing a second channel access procedure for the predetermined channel and transmitting the scheduled UL data to the wireless communication node.
The method of claim 1, wherein the predetermined event comprises expiration of a predetermined timer.
The method of claim 3, wherein the predetermined timer comprises one of: a predefined value, a value configured by radio resource control (RRC) information, and a value contained in the first downlink control message.
The method of claim 1, wherein the first downlink control message comprises:

first timing information that is used by the wireless communication device to transmit the scheduled UL data when the first channel access procedure is successfully completed prior to the predetermined event; and

second timing information that is used by the wireless communication device to transmit the scheduled UL data when the first channel access procedure is not successfully completed prior to the predetermined event.
The method claim 5, wherein the second timing information comprises:

a first part configured to indicate a time value that indicates when the first downlink control message will no longer be valid, and after which the wireless communication device should discard the UL data; and

a second part configured to indicate an offset value relative to a time when the notification message is transmitted, wherein the offset value informs the wireless communication device when to transmit the scheduled UL data on the predetermined channel prior to expiration of the time value.
The method of claim 1, further comprising:

when the first channel access procedure is successfully completed prior to the predetermined event, transmitting a second downlink control message to the wireless communication device, wherein the second downlink control message comprises:

an offset value relative to a time when the notification message is transmitted, wherein the offset value informs the wireless communication device when to transmit the scheduled UL data on the predetermined channel, wherein the specified timing comprises the offset value, and

wherein the first downlink control message comprises timing information used by the wireless communication device to transmit the scheduled UL data when the wireless communication device successfully completes a second channel access procedure prior to the wireless communication node successfully completing the first channel access procedure.
The method of claim 1, wherein the notification message triggers the wireless communication device to transmit UL data on multiple UL channels, including the predetermined UL channel, based on multiple timings, including the specified timing, respectively, provided by the wireless communication node, wherein the UL data was previously stored by the wireless communication device for transmission on the multiple UL channels.
The method of claim 8, wherein the multiple timings corresponding to the multiple UL channels is based on at least one of: a previously scheduled transmission order for each of the multiple UL channels, a hybrid automatic repeat request (HARQ) process number, a smallest control channel element (CCE) index for each UL channel, and a frequency domain starting position.
A method of scheduling uplink (UL) data transmissions performed by wireless communication device, comprising:

receiving a first downlink control message from a wireless communication node;

initiating a first channel access procedure for accessing a predetermined channel for transmitting scheduled UL data;

determining whether the first channel access procedure is successfully completed prior to a predetermined event;

when the first channel access procedure is completed prior to the predetermined event, transmitting the scheduled UL data in accordance with first timing information contained in the first downlink control message; and

when the first channel access procedure is not completed prior to the predetermined event, transmitting the scheduled UL data in accordance with second timing information provided by the wireless communication node.
The method of claim 10, wherein the predetermined event comprises:

the wireless communication node successfully completing a second channel access procedure for the predetermined channel and transmitting a notification message to the wireless communication device that notifies the wireless communication device that the wireless communication node has successfully completed the second channel access procedure,

wherein the notification message triggers the wireless communication device to transmit the scheduled UL data on the predetermined channel based on the second timing information provided by the wireless communication node.
The method of claim 10, wherein the predetermined event comprises expiration of a predetermined timer.
The method of claim 12, wherein the predetermined timer comprises one of: a predefined value, a value configured by radio resource control (RRC) information, and a value contained in the first downlink control message.
The method of claim 10, wherein the first downlink control message comprises:

first timing information that is used by the wireless communication device to transmit the scheduled UL data when the first channel access procedure is successfully completed prior to the predetermined event; and

second timing information that is used by the wireless communication device to transmit the scheduled UL data when the first channel access procedure is not successfully completed prior to the predetermined event.
The method claim 14, wherein the second timing information comprises:

a first part configured to indicate a time value that indicates when the first downlink control message will no longer be valid, and after which the wireless communication device should discard the scheduled UL data; and

a second part configured to indicate an offset value relative to a time when a notification message is transmitted from the wireless communication node to the wireless communication device, wherein the notification message notifies the wireless communication device that the wireless communication node has successfully completed a second channel access procedure, and wherein the offset value informs the wireless communication device when to transmit the scheduled UL data on the predetermined channel prior to expiration of the time value.
The method of claim 10, further comprising:

when the first channel access procedure is not successfully completed prior to the predetermined event, receiving a second downlink control message from the wireless communication node; and

when the first channel access procedure is successfully completed prior to the predetermined event, transmitting the scheduled UL data base on timing information contained in the first downlink control message.
The method of claim 16, wherein the second downlink control message comprises:

an offset value relative to a time when the second downlink control message is transmitted, wherein the offset value informs the wireless communication device when to transmit the scheduled UL data on the predetermined channel
The method of claim 17, wherein the second downlink control message triggers the wireless communication device to transmit UL data on multiple UL channels, including the predetermined channel, based on multiple timings, including the specified timing, respectively, provided by the wireless communication node, wherein the UL data was previously stored by the wireless communication device for transmission on the multiple UL channels.
The method of claim 18, wherein the multiple timings corresponding to the multiple UL channels is based on at least one of: a previously scheduled transmission order for each of the multiple UL channels, a hybrid automatic repeat request (HARQ) process number, a smallest control channel element (CCE) index for each UL channel, and a frequency domain starting position.
A non-transitory computer-readable storage medium storing computer-executable instructions that when executed perform any one of the methods of claims 1-19.
A wireless communication node, comprising:

a transceiver configured to transmit a first downlink control message to a wireless communication device; and

at least one processor configured to:

initiate a first channel access procedure for accessing a predetermined channel for receiving scheduled UL data from the wireless communication device; and

determine whether the first channel access procedure is successfully completed prior to a predetermined event,

wherein when the first channel access procedure is completed prior to the predetermined event, the transceiver is further configured to transmit a notification message to the wireless communication device that notifies the wireless communication device that the wireless communication node has successfully completed the first channel access procedure, and

wherein the notification message triggers the wireless communication device to transmit the scheduled UL data on the predetermined channel based on a specified timing provided by the wireless communication node.
The wireless communication node of claim 21, wherein the predetermined event comprises the wireless communication device successfully completing a second channel access procedure for the predetermined channel and transmitting the scheduled UL data to the wireless communication node.
The wireless communication node of claim 21, wherein the predetermined event comprises expiration of a predetermined timer.
The wireless communication node of claim 23, wherein the predetermined timer comprises one of: a predefined value, a value configured by radio resource control (RRC) information, and a value contained in the first downlink control message.
The wireless communication node of claim 21, wherein the first downlink control message contains first timing information that is used by the wireless communication device to transmit the scheduled UL data when the first channel access procedure is not successfully completed prior to the predetermined event, and second timing information that is used by the wireless communication device to transmit the scheduled UL data when the first channel access procedure is successfully completed prior to the predetermined event, wherein the specified timing comprises the second timing information.
The wireless communication node of claim 25, wherein the second timing information comprises:

a first part configured to indicate a time value that indicates when the first downlink control message will no longer be valid, and after which the wireless communication device should discard the UL data; and

a second part configured to indicate an offset value relative to a time when the notification message is transmitted, wherein the offset value informs the wireless communication device when to transmit the scheduled UL data on the predetermined channel prior to expiration of the time value.
The wireless communication node of claim 21, wherein:

when the first channel access procedure is successfully completed prior to the predetermined event, the transceiver is further configured to transmit a second downlink control message to the wireless communication device, wherein the second downlink control message comprises:

an offset value relative to a time when the notification message is transmitted, wherein the offset value informs the wireless communication device when to transmit the scheduled UL data on the predetermined channel, wherein the specified timing comprises the offset value, and

wherein the first downlink control message comprises timing information used by the wireless communication device to transmit the scheduled UL data when the wireless communication device successfully completes a second channel access procedure prior to the wireless communication node successfully completing the first channel access procedure.
The wireless communication node of claim 21, wherein the notification message triggers the wireless communication device to transmit UL data on multiple UL channels, including the predetermined UL channel, based on multiple timings, including the specified timing, respectively, provided by the wireless communication node, wherein the UL data was previously stored by the wireless communication device for transmission on the multiple UL channels.
The wireless communication node of claim 28, wherein the multiple timings corresponding to the multiple UL channels is based on at least one of: a previously scheduled transmission order for each of the multiple UL channels, a hybrid automatic repeat request (HARQ) process number, a smallest control channel element (CCE) index for each UL channel, and a frequency domain starting position.
A wireless communication device, comprising:

a transceiver configured to receive a first downlink control message from a wireless communication node; and

at least one processor configured to:

initiate a first channel access procedure for accessing to a predetermined channel for transmitting scheduled UL data; and

determine whether the first channel access procedure is successfully completed prior to a predetermined event,

wherein when the first channel access procedure is completed prior to the predetermined event, the transceiver is further configured to transmit the scheduled UL data in accordance with first timing information contained in the first downlink control message, and

wherein when the first channel access procedure is not completed prior to the predetermined event, the transceiver is further configured to transmit the scheduled UL data in accordance with second timing information provided by the wireless communication node.
The wireless communication device of claim 30, wherein the predetermined event comprises:

the wireless communication node successfully completing a second channel access procedure for the predetermined channel and transmitting a notification message to the wireless communication device that notifies the wireless communication device that the wireless communication node has successfully completed the second channel access procedure,

wherein the notification message triggers the wireless communication device to transmit the scheduled UL data on the predetermined channel based on the second timing information provided by the wireless communication node.
The wireless communication device of claim 30, wherein the predetermined event comprises expiration of a predetermined timer.
The wireless communication device of claim 32, wherein the predetermined timer comprises one of: a predefined value, a value configured by radio resource control (RRC) information, and a value contained in the first downlink control message.
The wireless communication device of claim 30, wherein the first downlink control message comprises:

first timing information that is used by the wireless communication device to transmit the scheduled UL data when the first channel access procedure is successfully completed prior to the predetermined event; and

second timing information that is used by the wireless communication device to transmit the scheduled UL data when the first channel access procedure is not successfully completed prior to the predetermined event.
The wireless communication device of claim 34, wherein the second timing information comprises:

a first part configured to indicate a time value that indicates when the first downlink control message will no longer be valid, and after which the wireless communication device should discard the scheduled UL data; and

a second part configured to indicate an offset value relative to a time when a notification message is transmitted from the wireless communication node to the wireless communication device,

wherein the notification message notifies the wireless communication device that the wireless communication node has successfully completed a second channel access procedure, and wherein the offset value informs the wireless communication device when to transmit the scheduled UL data on the predetermined channel prior to expiration of the time value.
The wireless communication device of claim 30, wherein:

when the first channel access procedure is not successfully completed prior to the predetermined event, the transceiver is further configured to receive a second downlink control message from the wireless communication node; and

when the first channel access procedure is successfully completed prior to the predetermined event, the transceiver is further configured to transmit the scheduled UL data base on timing information contained in the first downlink control message.
The wireless communication device of claim 36, wherein the second downlink control message comprises:

an offset value relative to a time when the second downlink control message is transmitted, wherein the offset value informs the wireless communication device when to transmit the scheduled UL data on the predetermined channel
The wireless communication device of claim 37, wherein the second downlink control message triggers the wireless communication device to transmit UL data on multiple UL channels, including the predetermined channel, based on multiple timings, including the specified timing, respectively, provided by the wireless communication node, wherein the UL data was previously stored by the wireless communication device for transmission on the multiple UL channels.
The wireless communication device of claim 38, wherein the multiple timings corresponding to the multiple UL channels is based on at least one of: a previously scheduled transmission order for each of the multiple UL channels, a hybrid automatic repeat request (HARQ) process number, a smallest control channel element (CCE) index for each UL channel, and a frequency domain starting position.
The wireless communication device of claim 30 wherein the predetermined channel comprises a physical uplink shared channel (PUSCH) .