Patent Description:
Over the past few decades, mobile communications have evolved from voice services to high-speed broadband data services. With further development of new types of services and applications, e.g., enhanced mobile broadband (eMBB), massive Machine-Type Communication (mMTC), Ultra Reliability Low Latency Communication (URLLC), etc., the demands for high-performance data transmission on mobile networks will continue to increase exponentially. Based on specific requirements in these emerging services, wireless communication systems should meet a variety of requirements, such as throughput, latency, data rate, capacity, reliability, link density, cost, energy consumption, complexity, and coverage. 3GPP R2-<NUM> relates to the impact of extending the RAR window size in NR-U.

Traditional methods which rely on random access of user terminals and scheduled data transmissions between a base station and a user terminal fail to provide satisfactory performance for the aforementioned services due to limited equipment capacity, high latency, and high signaling overhead. In order to meet these demands in <NUM>/NR (New Radio) communications, a grant-free data transmission method based on competition is being considered. A random access (RACH) procedure is important during initial access from RRC (radio resource control) idle, when performing a RRC connection establishment procedure, for downlink or uplink data transmission when a wireless communication device is not synchronized, and during handover when uplink synchronization is need in a target cell, etc..

To access an unlicensed spectrum during a RACH procedure, a listen-before-talk (LBT) process is required, in which a CCA (clear channel assessment) is performed. The CCA determines the availability of a channel by detecting a presence of any existing signal on the channel. If signals are detected and the channel is occupied, a next LBT process can be performed after a time period until a non-occupied channel is detected, followed by a data transmission. Such a LBT process is performed during each step of a RACH procedure when accessing an unlicensed spectrum, resulting in increased latency and disadvantageously affecting the system performance. Further, when a random access preamble is transmitted and a ra-Response Window is started, if a random access response (RAR) is not received before the expiration of the ra-ResponseWindow, the RAR is failed. Thus, there exists a need to develop a new method to reduce latency in a RACH procedure when accessing an unlicensed spectrum.

The exemplary embodiments disclosed herein are directed to solving the issues related to one or more 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.

It is noted that various features are not necessarily drawn to scale. In fact, the dimensions and geometries of the various features may be arbitrarily increased or reduced for clarity of discussion.

Embodiments of the present invention are described in detail with reference to the accompanying drawings. The same or similar components may be designated by the same or similar reference numerals although they are illustrated in different drawings. Detailed descriptions of constructions or processes well-known in the art may be omitted to avoid obscuring the subject matter of the present invention. Further, the terms are defined in consideration of their functionality in embodiment of the present invention, and may vary according to the intention of a user or an operator, usage, etc. Therefore, the definition should be made on the basis of the overall content of the present specification.

<FIG> illustrates an exemplary wireless communication network <NUM>, in accordance with some embodiments of the present disclosure. In a wireless communication system, a network side communication node or a base station (BS) can be a node B, an E-utran Node B (also known as Evolved Node B, eNodeB or eNB), a pico station, a femto station, or the like. A terminal side node or a user equipment (UE) can be a long range communication system like a mobile phone, a smart phone, a personal digital assistant (PDA), tablet, laptop computer, or a short range communication system such as, for example a wearable device, a vehicle with a vehicular communication system and the like. A network and a terminal side communication node are represented by a BS <NUM> and a UE <NUM>, respectively, which are generally referred to as "communication nodes" hereinafter in all the embodiments in this disclosure. Such communication nodes may be capable of wireless and/or wired communications, in accordance with some embodiments of the invention. It is noted that all the embodiments are merely preferred examples, and are not intended to limit the present disclosure. Accordingly, it is understood that the system may include any desired combination of UE's and BSs, while remaining within the scope of the present disclosure.

Referring to <FIG>, the wireless communication network <NUM> includes a BS <NUM> and a UE 104a, and a UE 104b (collectively referred to as UE's <NUM> herein). The BS <NUM> and the UE's <NUM> are contained within a geographic boundary of cell <NUM>. A wireless transmission from a transmitting antenna of the UE <NUM> to a receiving antenna of the BS <NUM> is known as an uplink transmission, and a wireless transmission from a transmitting antenna of the BS <NUM> to a receiving antenna of the UE <NUM> is known as a downlink transmission. Although only <NUM> UE's <NUM> are shown in <FIG>, it should be noted that any number of UE's <NUM> can be included in the cell <NUM> and are within the scope of this invention. In some embodiments, the coverage of uplink communication 105b is larger than that of the uplink communication 105a, as indicated by dotted circles <NUM> and <NUM>, respectively. The BS <NUM> is located at the intercept region of the coverage areas <NUM> and <NUM> in order for the BS <NUM> to perform uplink communication with the UE 104a and UE 104b in the cell <NUM>.

The direct communication channels <NUM>/<NUM> between the UE's <NUM> and the BS <NUM> can be through interfaces such as an Uu interface, which is also known as UMTS (Universal Mobile Telecommunication System (UMTS) air interface. The direct communication channels (sidelink transmission) <NUM> between the UE's can be through a PC5 interface, which is introduced to address high moving speed and high density applications such as Vehicle-to-Vehicle (V2V) communications. The BS <NUM> is connected to a core network (CN) <NUM> through an external interface <NUM>, e.g., an Iu interface.

The UE's 104a and 104b obtains its synchronization timing from the BS <NUM>, which obtains its own synchronization timing from the core network <NUM> through an internet time service, such as a public time NTP (Network Time Protocol) server or a RNC (Radio Frequency Simulation System Network Controller) server. This is known as network-based synchronization. Alternatively, the BS <NUM> can also obtain synchronization timing from a Global Navigation Satellite System (GNSS) (not shown) through a satellite signal <NUM>, especially for a large BS in a large cell which has a direct line of sight to the sky, which is known as satellite-based synchronization.

<FIG> illustrates a block diagram of an exemplary wireless communication system <NUM>, in accordance with some embodiments of the present disclosure. The system <NUM> may include components and elements configured to support known or conventional operating features that need not be described in detail herein. In one exemplary embodiment, system <NUM> can be used to transmit and receive data symbols in a wireless communication environment such as the wireless communication network <NUM> of <FIG>, as described above.

System <NUM> generally includes a BS <NUM> and two UEs 104a and 104b, collectively referred to as UE <NUM> below for ease of discussion. The BS <NUM> includes a BS transceiver module <NUM>, a BS antenna array <NUM>, a BS memory module <NUM>, a BS processor module <NUM>, and a Network interface <NUM>, each module being coupled and interconnected with one another as necessary via a data communication bus <NUM>. The UE <NUM> includes a UE transceiver module <NUM>, a UE antenna <NUM>, a UE memory module <NUM>, a UE processor module <NUM>, and an input/output (I/O) interface <NUM>, each module being coupled and interconnected with one another as necessary via a date communication bus <NUM>. The BS <NUM> communicates with the UE <NUM> via a communication channel <NUM>, which can be any wireless channel or other medium known in the art suitable for transmission of data as described herein.

As would be understood by persons of ordinary skill in the art, system <NUM> may further include any number of blocks, modules, circuits, etc. other than those shown in <FIG>.

A wireless transmission from a transmitting antenna of the UE <NUM> to a receiving antenna of the BS <NUM> is known as an uplink transmission, and a wireless transmission from a transmitting antenna of the BS <NUM> to a receiving antenna of the UE <NUM> is known as a downlink transmission. In accordance with some embodiments, a UE transceiver <NUM> may be referred to herein as an "uplink" transceiver <NUM> that includes a RF transmitter and receiver circuitry that are each coupled to the UE antenna <NUM>. Similarly, in accordance with some embodiments, the BS transceiver <NUM> may be referred to herein as a "downlink" transceiver <NUM> that includes RF transmitter and receiver circuitry that are each coupled to the antenna array <NUM>. A downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna array <NUM> in time duplex fashion. The operations of the two transceivers <NUM> and <NUM> are coordinated in time such that the uplink receiver is coupled to the uplink UE antenna <NUM> for reception of transmissions over the wireless communication channel <NUM> at the same time that the downlink transmitter is coupled to the downlink antenna array <NUM>. Preferably, there is close synchronization timing with only a minimal guard time between changes in duplex direction. The UE transceiver <NUM> communicates through the UE antenna <NUM> with the BS <NUM> via the wireless communication channel <NUM> or with other UEs via the wireless communication channel <NUM>. The wireless communication channel <NUM> can be any wireless channel or other medium known in the art suitable for sidelink transmission of data as described herein.

The UE transceiver <NUM> and the BS transceiver <NUM> are configured to communicate via the wireless data communication channel <NUM>, and cooperate with a suitably configured RF antenna arrangement <NUM>/<NUM> that can support a particular wireless communication protocol and modulation scheme. In some embodiments, the BS transceiver <NUM> is configured to transmit the physical downlink control channel (PDCCH) and configured slot structure related information (SFI) entry set to the UE transceiver <NUM>. In some embodiments, the UE transceiver <NUM> is configured to receive PDCCH containing at least one SFI field from the BS transceiver <NUM>. In some exemplary embodiments, the UE transceiver <NUM> and the BS transceiver <NUM> are configured to support industry standards such as the Long Term Evolution (LTE) and emerging <NUM> standards, and the like. It is understood, however, that the invention is not necessarily limited in application to a particular standard and associated protocols. Rather, the UE transceiver <NUM> and the BS transceiver <NUM> may be configured to support alternate, or additional, wireless data communication protocols, including future standards or variations thereof.

The BS processor modules <NUM> and UE processor modules <NUM> are implemented, or realized, with a general purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein.

Then the UE processor module <NUM> detects the PHR triggering message on the UE transceiver module <NUM>, the UE processor module <NUM> is further configured to determine at least one second SFI entry set based on at least one predefined algorithm and the received at least one first SFI entry set configured by the BS <NUM>, wherein the at least one predefined algorithm is selected based on other parameters calculated or messages received. The UE processor module <NUM> is further configured to generate the at least one second SFI entry set and monitor the PDCCH received on the UE transceiver module <NUM> to further receive the at least one SFI field. As used herein, "SFI entry set" means SFI table or SFI entries.

In this regard, the memory modules <NUM> and <NUM> may be coupled to the processor modules <NUM> and <NUM>, respectively, such that the processors modules <NUM> and <NUM> can read information from, and write information to, memory modules <NUM> and <NUM>, respectively.

The network interface <NUM> generally represents the hardware, software, firmware, processing logic, and/or other components of the base station <NUM> that enable bi-directional communication between BS transceiver <NUM> and other network components and communication nodes configured to communication with the BS <NUM>. For example, network interface <NUM> may be configured to support internet or WiMAX traffic. In a typical deployment, without limitation, network interface <NUM> provides an <NUM> Ethernet interface such that BS transceiver <NUM> can communicate with a conventional Ethernet based computer network. In this manner, the network interface <NUM> may include a physical interface for connection to the computer network (e.g., Mobile Switching Center (MSC)). The terms "configured for" or "configured to" as used herein with respect to a specified operation or function refers to a device, component, circuit, structure, machine, signal, etc. that is physically constructed, programmed, formatted and/or arranged to perform the specified operation or function. The network interface <NUM> could allow the BS <NUM> to communicate with other BSs or core network over a wired or wireless connection.

Referring again to <FIG>, as mentioned above, the BS <NUM> repeatedly broadcasts system information associated with the BS <NUM> to one or more UEs (e.g., <NUM>) so as to allow the UE <NUM> to access the network within the cell <NUM> where the BS <NUM> is located, and in general, to operate properly within the cell <NUM>. Plural information such as, for example, downlink and uplink cell bandwidths, downlink and uplink configuration, configuration for random access, etc., can be included in the system information, which will be discussed in further detail below. Typically, the BS <NUM> broadcasts a first signal carrying some major system information, for example, configuration of the cell <NUM> through a PBCH (Physical Broadcast Channel). For purposes of clarity of illustration, such a broadcasted first signal is herein referred to as "first broadcast signal. " It is noted that the BS <NUM> may subsequently broadcast one or more signals carrying some other system information through respective channels (e.g., a Physical Downlink Shared Channel (PDSCH)), which are herein referred to as "second broadcast signal," "third broadcast signal," and so on.

Referring again to <FIG>, in some embodiments, the major system information carried by the first broadcast signal may be transmitted by the BS <NUM> in a symbol format via the communication channel <NUM>. In accordance with some embodiments, an original form of the major system information may be presented as one or more sequences of digital bits and the one or more sequences of digital bits may be processed through plural steps (e.g., coding, scrambling, modulation, mapping steps, etc.), all of which can be processed by the BS processor module <NUM>, to become the first broadcast signal. Similarly, when the UE <NUM> receives the first broadcast signal (in the symbol format) using the UE transceiver <NUM>, in accordance with some embodiments, the UE processor module <NUM> may perform plural steps (de-mapping, demodulation, decoding steps, etc.) to estimate the major system information such as, for example, bit locations, bit numbers, etc., of the bits of the major system information. The UE processor module <NUM> is also coupled to the I/O interface <NUM>, which provides the UE <NUM> with the ability to connect to other devices such as computers. The I/O interface <NUM> is the communication path between these accessories and the UE processor module <NUM>.

In some embodiments, the UE <NUM> can operate in a hybrid communication network in which the UE communicates with the BS <NUM>, and with other UEs, e.g., between 104a and 104b. As described in further detail below, the UE <NUM> supports sidelink communications with other UE's as well as downlink/uplink communications between the BS <NUM> and the UE <NUM>. As discussed above, sidelink communication allows the UEs 104a and 104b to establish a direct communication link with each other, or with other UEs from different cells, without requiring the BS <NUM> to relay data between UE's.

<FIG> illustrates a method <NUM> of performing a <NUM>-step contention-based Random Access (RACH) procedure in a wireless communication system, according to some embodiments of the present disclosure. In the illustrated embodiment, the wireless communication system comprises a BS <NUM> and a UE <NUM>. It is understood that additional operations may be provided before, during, and after the method <NUM> of <FIG>, and that some other operations may be omitted or only briefly described herein. It should be noted <FIG> is an example for illustration and discussion purposes.

The method <NUM> starts with operation <NUM> in which the UE <NUM> receives first information from the BS <NUM> according to some embodiments. In some embodiments, the first information comprises information of a plurality of time windows including at least one of the following: a number of a plurality of time windows and a size of each of the plurality of time windows. In some embodiments, the first information is transmitted in system information or a Radio Resource Control (RRC) message. In some embodiments, each of the plurality of time windows is configured for receiving a RA response by the UE <NUM> from the BS <NUM>. In some embodiments, the plurality of time windows comprises at least one of the following: at least one ra-ResponseWindow and at least one time offset. In some embodiments, the information of the plurality of time windows can be received by the UE <NUM> from the BS <NUM> through an RRC message. In some embodiments, the first information further comprises at least one Search Space (SS) and at least one Control Resource Set (CORESET). In some embodiments, the at least one SS and the at least one CORESET provides information of resources in the time and frequency domain for receiving Downlink Control Information (DCI) on a Physical Downlink Control Channel (PDCCH) in a RA response by the UE <NUM> from the BS <NUM>. In some embodiments, RACH configurations, e.g., random access preamble format, transmission timing, and PRACH index, are also configured to the UE <NUM> through the system information or the RRC message.

In some embodiments, the first information further comprises a correlation between each of the plurality of time windows and at least one of the following: the at least one CORESET and the at least one SS. In some embodiments, each of the plurality of time windows can be distinguished by at least one of the following: a corresponding Control Resource Set (CORESET) and a corresponding Search Space (SS). For example, <NUM> time windows can be configured can be configured to the UE <NUM> via system information or a RRC message. The <NUM> time windows comprises a first time window and a second time window. The first time window is a first ra-ResponseWindow and the second time window is one of the following: a second ra-ResponseWindow and a time offset. In some embodiments, the first time window is determined by a first CORESET and by a first SS; and the second time window is determined by a second CORESET and a second SS. In some embodiments, the first CORESET and the second CORESET each comprises information of resources on the frequency domain for receiving the DCI on the PDCCH. In some embodiments, the first SS and the second SS each comprises information of resource on the time domain for receiving the DCI on the PDCCH. In some embodiments, the first CORESET is the same as the second CORESET, i.e., same resource in the frequency domain for receiving the DCI on the PDCCH. In some other embodiments, the first CORESET is different from the second CORESET. In some embodiments, the first SS is the same as the second SS. In some other embodiments, the first SS is different from the second SS.

The method <NUM> continues with operation <NUM> in which the UE <NUM> transmits a random access preamble and scheduled transmission to the BS <NUM> according to some embodiments. Before transmitting the random access preamble to the BS <NUM>, the UE <NUM> performs a LBT process on the selected at least one PRACH occasion. In some embodiments, the LBT process comprises sensing interference and bursty arrivals of packets through its transmitters to determine interference level and traffic loads on the uplink carrier. If the LBT process fails, the UE <NUM> restarts the LBT process at the following PRACH occasion on the corresponding uplink carrier until the LBT process passes (i.e., the uplink carrier is available and unoccupied). The UE <NUM> then starts first transmissions of random access preambles to the BS <NUM> on the PRACH occasion. The UE <NUM> starts a first time window (i.e., ra-ResponseWindow) at the start (i.e., t0) of a first PDCCH occasion. In some embodiments, the size of the time window in the time domain is preconfigured by the system and transmitted to the UE <NUM> in the system information.

The method <NUM> continues with operation <NUM> in which the BS <NUM> transmits a random access (RA) response and contention resolution to the UE <NUM>, according to some embodiments. In some embodiments, the RA response comprises a MAC Random Access Response (RAR). In some embodiments, the DCI is transmitted on the PDCCH and the MAC RAR is transmitted on the PDSCH. Continue with the example above, the UE <NUM> monitor the PDCCH on resources defined by the first SS and the first CORESET, which corresponds to the first time window.

In some embodiments, when the MAC RAR is not received before the end of the first time window (i.e., the first ra-ResponseWindow), and when the second time window is a second ra-ResponseWindow, the UE <NUM> starts a second ra-ResponseWindow at time t1. In some embodiments, the time t1 is the end of the first PDCCH occasion and at the start of a second PDCCH occasion. In some other embodiments, when the MAC RAR is received before the end of the first time window (i.e., the first ra-ResponseWindow), the second time window is not initiated.

In some other embodiments, the MAC RAR is not received before the end of the first time window (i.e., the first ra-ResponseWindow) at t1, and when the second time window is a time offset, the UE <NUM> continues with the monitoring of the first PDCCH within the time offset.

In some embodiments, each of the plurality of time windows can be distinguished by a window indication in the RA response received by the UE <NUM> from the BS <NUM>. In some embodiments, the window indication to indicate a time window is transmitted in one of the following: the DCI on the PDCCH and the MAC RAR on the PDSCH. For example, <NUM> time windows can be configured to the UE <NUM> via system information or a RRC message. The <NUM> time windows comprise a first time window and a second time window. The first time window is a first ra-ResponseWindow and the second time window is one of the following: a second ra-ResponseWindow and a time offset.

In some embodiments, the MAC RAR comprises a window indication (WI) field with at least one bit for window indication. For example, a value of <NUM> of the WI field indicates the first time window is used; and a value of <NUM> of the WI field indicates the second time window is used. For example, when the UE <NUM> receives the RAR message from the BS <NUM> within the first time window (i.e., the first ra-ResponseWindow), when the RAR message comprises a preamble matches the preamble transmitted in the Random Access preamble message, and when the WI field has a value of <NUM>, the RAR message is successfully received by the UE <NUM>. Similarly, when the UE <NUM> receives the RAR message from the BS <NUM> within the second time window (i.e., the second ra-ResponseWindow), when the RA response message comprises a preamble matches the preamble transmitted in the Random Access Preamble Message, and when the WI field has a value of <NUM>, the RAR message from the BS <NUM> is successfully received by the UE <NUM>. For another example, when the RAR message comprises a preamble matches the preamble transmitted in the Random Access preamble message, and when the WI field has a value of <NUM>, the reception of the RAR message by the UE <NUM> is failed. Similarly, when the UE <NUM> receives the RAR message from the BS <NUM> within the second time window (i.e., the second ra-ResponseWindow), when the RAR message comprises a preamble matches the preamble transmitted in the Random Access Preamble Message, and when the WI field has a value of <NUM>, the reception of the RAR message from the BS <NUM> by the UE <NUM> is failed.

In some other embodiments, the MAC RAR comprises a window indication (WI) field with at least one bit for window and time offset indication. For example, a value of <NUM> of the WI field indicates the first time window is used; and a value of <NUM> of the WI field indicates the second time window is used. For example, when the UE <NUM> receives the RAR message from the BS <NUM> within the first time window (i.e., the first ra-ResponseWindow), when the RAR message comprises a preamble matches the preamble transmitted in the Random Access preamble message, and when the WI field has a value of <NUM>, the RAR message is successfully received by the UE <NUM>. Similarly, when the UE <NUM> receives the RAR message from the BS <NUM> within the second time window (i.e., the time offset), when the RAR message comprises a preamble matches the preamble transmitted in the Random Access Preamble Message, and when the WI field has a value of <NUM>, the RAR message from the BS <NUM> is successfully received by the UE <NUM>. For another example, when the UE <NUM> receives the RAR message from the BS <NUM> within the first time window (i.e., the first ra-ResponseWindow), when the RAR message comprises a preamble matches the preamble transmitted in the Random Access preamble message, and when the WI field has a value of <NUM>, the reception of the RAR message by the UE <NUM> is failed. Similarly, when the UE <NUM> receives the RAR message from the BS <NUM> within the second time window (i.e., the time offset), when the RAR message comprises a preamble matches the preamble transmitted in the Random Access Preamble Message, and when the WI field has a value of <NUM>, the reception of the RAR message from the BS <NUM> by the UE <NUM> is failed.

In some embodiments, each of the plurality of time windows can be indicated by a Start Frame number (SFN) of a RACH occasion for transmitting the random access preamble in the first message. In some embodiments, the SFN of a RACH occasion is determined by the BS <NUM> according to the SFN of receiving the random access preamble. In some embodiments, the SFN can be transmitted in one of the following: a MAC RAR and a DCI. For example, <NUM> bits in a MAC RAR or DCI can be used for representing the SFN for transmitting the radio access preamble. <NUM> lower bits of the <NUM> bits can be used for indicating the SFN. For another example, a radio frame in the MAC RAR or DCI can be used for representing the SFN for transmitting the radio access preamble. The radio frame is the SFN mod N, wherein N is an integer.

When the UE <NUM> receives the MACR RAR or the DCI, the UE <NUM> compares the SFN in the MAC RAR or the DCI with the SFN used for transmitting the random access preamble so as to differentiate different time windows. If the SFN in the MAC RAR or the DCI received by the UE <NUM> from the BS <NUM> in a first time window matches the SFN for transmitting the random access preamble by the UE <NUM>, the random access response is received successfully by the UE <NUM>. If the SFN in the MAC RAR or the DCI received by the UE <NUM> from the BS <NUM> in a first time window does not match the SFN for transmitting the random access preamble by the UE <NUM>, the random access response is failed.

The method <NUM> starts with operation <NUM> in which the UE <NUM> receives first information from the BS <NUM> according to some embodiments. In some embodiments, the first information comprises information of a plurality of time windows including at least one of the following: a number of a plurality of time windows and a size of each of the plurality of time windows. In some embodiments, the first information is transmitted in system information or a RRC message. In some embodiments, each of the plurality of time windows is configured for receiving a RA response by the UE <NUM> from the BS <NUM>. In some embodiments, the plurality of time windows comprises at least one of the following: at least one ra-ResponseWindow and at least one time offset. In some embodiments, the information of the plurality of time windows can be received by the UE <NUM> from the BS <NUM> through an RRC message. In some embodiments, the first information comprises at least one Search Space (SS) and at least one Control Resource Set (CORESET). In some embodiments, the at least one SS and the at least one CORESET provides information of resources in the time and frequency domain for receiving Downlink Control Information (DCI) on a Physical Downlink Control Channel (PDCCH) in a RA response by the UE <NUM> from the BS <NUM>. In some embodiments, RACH configurations, e.g., random access preamble format, transmission timing, and PRACH configuration index, are also configured to the UE <NUM> through the system information or the RRC message.

In some embodiments, the first information further comprises a correlation between each of the plurality of time windows and at least one of the following: the at least one CORESET and the at least one SS. In some embodiments, each of the plurality of time windows can be distinguished by at least one of the following: a corresponding Control Resource Set (CORESET) and a corresponding Search Space (SS). For example, <NUM> time windows can be configured to the UE <NUM> via system information or a RRC message. The <NUM> time windows comprise a first time window and a second time window. The first time window is a first ra-ResponseWindow and the second time window is one of the following: a second ra-ResponseWindow and a time offset. In some embodiments, the first time window is determined by a first CORESET and by a first SS; and the second time window is determined by a second CORESET and a second SS. In some embodiments, the first CORESET and the second CORESET each comprises information of resources on the frequency domain for receiving the DCI on the PDCCH. In some embodiments, the first SS and the second SS each comprises information of resource on the time domain for receiving the DCI on the PDCCH. In some embodiments, the first CORESET is the same as the second CORESET, i.e., same resource in the frequency domain for receiving the DCI on the PDCCH. In some other embodiments, the first CORESET is different from the second CORESET. In some embodiments, the first SS is the same as the second SS. In some other embodiments, the first SS is different from the second SS.

The method <NUM> continues with operation <NUM> in which the UE <NUM> transmits a random access preamble to the BS <NUM> according to some embodiments. Before transmitting the random access preamble to the BS <NUM>, the UE <NUM> performs a LBT process on the selected at least one PRACH occasion. In some embodiments, the LBT process comprises sensing interference and bursty arrivals of packets through its transmitters to determine interference level and traffic loads on the uplink carrier. If the LBT process fails, the UE <NUM> restarts the LBT process at the following PRACH occasion on the corresponding uplink carrier until the LBT process passes (i.e., the uplink carrier is available and unoccupied). The UE <NUM> then starts first transmissions of random access preambles to the BS <NUM> on the PRACH occasion. The UE <NUM> starts a first time window (i.e., ra-ResponseWindow) at the start (i.e., t0) of a first PDCCH occasion. In some embodiments, the size of the time window in the time domain is preconfigured by the system and transmitted to the UE <NUM> in the system information.

The method <NUM> continues with operation <NUM> in which the BS <NUM> transmits a random access (RA) response to the UE <NUM>, according to some embodiments. In some embodiments, the RA response comprises a MAC Random Access Response (RAR), which are generated according to the random access preamble received from the UE <NUM>. In some embodiments, the DCI is transmitted on the PDCCH and the MAC RAR is transmitted on the PDSCH. Continue with the example above, the UE <NUM> monitor the PDCCH on resources defined by the first SS and the first CORESET, which corresponds to the first time window.

In some embodiments, the MAC RAR comprises a window indication (WI) field with at least one bit for window indication. An example of a MAC RAR format is discussed below in <FIG>. For example, a value of <NUM> of the WI field indicates the first time window is used; and a value of <NUM> of the WI field indicates the second time window is used. For example, when the UE <NUM> receives the RAR message from the BS <NUM> within the first time window (i.e., the first ra-ResponseWindow), when the RAR message comprises a preamble matches the preamble transmitted in the Random Access preamble message, and when the WI field has a value of <NUM>, the RAR message is successfully received by the UE <NUM>. Similarly, when the UE <NUM> receives the RAR message from the BS <NUM> within the second time window (i.e., the second ra-ResponseWindow), when the RA response message comprises a preamble matches the preamble transmitted in the Random Access Preamble Message, and when the WI field has a value of <NUM>, the RAR message from the BS <NUM> is successfully received by the UE <NUM>. For another example, when the RAR message comprises a preamble matches the preamble transmitted in the Random Access preamble message, and when the WI field has a value of <NUM>, the reception of the RAR message by the UE <NUM> is failed. Similarly, when the UE <NUM> receives the RAR message from the BS <NUM> within the second time window (i.e., the second ra-ResponseWindow), when the RAR message comprises a preamble matches the preamble transmitted in the Random Access Preamble Message, and when the WI field has a value of <NUM>, the reception of the RAR message from the BS <NUM> by the UE <NUM> is failed.

<FIG> illustrates an exemplary format of a MAC RAR <NUM>, in accordance with some embodiments of the present disclosure. In the illustrated embodiment, the MAC RAR <NUM> is transmitted on a PDSCH and comprises a window indication field <NUM> occupying first <NUM> bit <NUM> of a first Oct <NUM>-<NUM> (Oct <NUM>). In the illustrated embodiment, the MAC RAR <NUM> further comprises a first Timing Advance Command field <NUM> occupying last <NUM> bits <NUM> of the first Oct (Oct <NUM>), a second Timing Advance Command field <NUM> occupying first <NUM> bits <NUM> of a second Oct <NUM>-<NUM> (Oct <NUM>), a first UL Grant field <NUM> occupying last <NUM> bits <NUM> of the second Oct <NUM>-<NUM> (Oct <NUM>), a second UL Grant field <NUM> occupying <NUM> bits <NUM> of a third Oct <NUM>-<NUM> (Oct <NUM>), a third UL Grant field <NUM> occupying <NUM> bits <NUM> of a fourth Oct <NUM>-<NUM> (Oct <NUM>), and a fourth UL Grant field <NUM> occupying <NUM> bits <NUM> of a fifth Oct <NUM>-<NUM> (Oct <NUM>). In the illustrated embodiment, the MAC RAR <NUM> further comprises a first temporary C-RNTI field <NUM> occupying <NUM> bits <NUM> of a sixth Oct <NUM>-<NUM> (Oct <NUM>) and a second temporary C-RNTI field <NUM> occupying <NUM> bits <NUM> of a seventh Oct <NUM>-<NUM> (Oct <NUM>). It should be noted that <FIG> is an exemplary format of the MAC RAR <NUM> and is not intended to be limiting. Any MAC RAR with a WI field can be used and is within the scope of this invention.

The method <NUM> continues with operation <NUM> in which a scheduled transmission is received by the BS <NUM> from the UE <NUM> according to some embodiments. In some embodiments, the scheduled transmission is received by the BS <NUM> on the PUSCH. In some embodiments, the scheduled transmission is received on resources in the time and frequency domain indicated by the MAC RAR received by the UE <NUM> from the BS <NUM>.

The method <NUM> continues with operation <NUM> in which a contention-resolution message is generated and transmitted by the BS <NUM> to the UE <NUM> according to some embodiments. In some embodiments, the contention resolution message comprises random access connection setup from the BS <NUM>. In some embodiments, the BS <NUM> perform a LBT process to determine the availability of the downlink carriers before transmitting the contention resolution message.

<FIG> illustrates a method <NUM> of performing a <NUM>-step contention-based Random Access (RACH) procedure in a wireless communication system, according to some embodiments of the present disclosure. In the illustrated embodiment, the wireless communication system comprises a BS <NUM> and a UE <NUM>. It is understood that additional operations may be provided before, during, and after the method <NUM> of <FIG>, and that some other operations may be omitted or only briefly described herein. It should be noted <FIG> is an example for illustration and the <NUM>-step contention-based RACH process of <FIG> is used for discussion purposes. It should be noted that the method <NUM> can be also used in a <NUM>-step contention-based RACH process.

The method <NUM> starts with operation <NUM> in which the UE <NUM> receives first information from the BS <NUM> according to some embodiments. In some embodiments, the first information comprises information of a time windows. In some embodiments, the first information is transmitted in system information or a Radio Resource Control (RRC) message. In some embodiments, the time windows is configured for receiving a RA response by the UE <NUM> from the BS <NUM>. In some embodiments, a size of the time window (e.g., <NUM> millisecond) is configured by the BS <NUM> in the first information.

The method <NUM> continues with operation <NUM> in which the UE <NUM> transmits a random access preamble and scheduled transmission to the BS <NUM> according to some embodiments. Before transmitting the random access preamble to the BS <NUM>, the UE <NUM> performs a LBT process on the selected at least one PRACH occasion. In some embodiments, the LBT process comprises sensing interference and bursty arrivals of packets through its transmitters to determine interference level and traffic loads on the uplink carrier. If the LBT process fails, the UE <NUM> restarts the LBT process at the following PRACH occasion on the corresponding uplink carrier until the LBT process passes (i.e., a channel is available and unoccupied). The UE <NUM> then starts first transmissions of random access preambles to the BS <NUM> on the PRACH occasion. The UE <NUM> starts the time window <NUM> (i.e., ra-ResponseWindow) at the start (i.e., t0) <NUM> of a first PDCCH occasion.

The method <NUM> continues with operation <NUM> in which the BS <NUM> generates and transmits a random access (RA) response and contention resolution to the UE <NUM>, according to some embodiments. The BS <NUM> further calculates RA-RNTI (Random Access- Radio Network Temporary Identifier) values according to information of the resources on which the random access preambles are transmitted on the frequency domain. In some embodiments, the RA-RNTI value can be is a function of at least one of the following: an index of the first frequency of the PRACH occasion in a system frame and a UL carrier used for the random access preamble.

In some embodiments, the RA response comprises a MAC Random Access Response (RAR). In some embodiments, the DCI is transmitted on the PDCCH and the MAC RAR is transmitted on the PDSCH. In some embodiments, before transmitting, the MAC RAR or the DCI is scrambled by the RA-RNTI determined by the BS <NUM> according to the information of the resources on which the random access preamble is transmitted on the frequency domain. In some embodiments, information of the resources on which the random access preamble is transmitted on the time domain is included in one of the following: the MAC RAR and the DCI.

In some embodiments, the UE <NUM> further calculates RA-RNTI value according to the frequency-domain information of the resource on which the random access preamble is transmitted. When the RA-RNTI scrambled MAC RAR or DCI is received by the UE <NUM> from the BS <NUM> within the time window <NUM>, the UE <NUM> descrambles the MAC RAR or the DCI using the calculated RA-RNTI. If the scrambled MAC RAR can be descrambled by the UE <NUM> according to the calculated RA-RNTI, the frequency-domain information of the resources used by the BS <NUM> for determining the RA-RNTI matches the frequency-domain information of the resources used by the UE <NUM> for determining the RA-RNTI. When the MAC-RAR is successfully descrambled, the time-domain information of the resources can be determined and further compared with the time-domain information of the resources on which the random access preamble is transmitted by the UE <NUM>. When the time-domain information of resources on which the random access preamble is transmitted by the UE <NUM> matches the time-domain information of resource in the MAC-RAR, the random access response is successfully received by the UE. When the time-domain information of resources on which the random access preamble is transmitted by the UE <NUM> does not match the time-domain information of resources in the MAC-RAR or the RA-RNTI scrambled MAC RAR or DCI is not received within the time window <NUM>, the random access response is failed.

The method <NUM> starts with operation <NUM> in which the UE <NUM> receives first information from the BS <NUM> according to some embodiments. In some embodiments, the first information comprises information of a time windows. In some embodiments, the first information is transmitted in system information or a Radio Resource Control (RRC) message. In some embodiments, the time windows is configured for receiving a RA response by the UE <NUM> from the BS <NUM>. In some embodiments, a size of the time window (e.g., <NUM> millisecond) is configured by the BS <NUM>.

The method <NUM> starts with operation <NUM> in which the UE <NUM> transmits a random access preamble and scheduled transmission to the BS <NUM> according to some embodiments. Before transmitting the random access preamble to the BS <NUM>, the UE <NUM> performs a LBT process on the selected at least one PRACH occasion. In some embodiments, the LBT process comprises sensing interference and bursty arrivals of packets through its transmitters to determine interference level and traffic loads on the uplink carrier. If the LBT process fails, the UE <NUM> restarts the LBT process at the following PRACH occasion on the corresponding uplink carrier until the LBT process passes (i.e., a channel is available and unoccupied). The UE <NUM> then starts first transmissions of random access preambles to the BS <NUM> on the PRACH occasion. The UE <NUM> starts the time window <NUM> (i.e., ra-ResponseWindow) at the start (i.e., t0) <NUM> of a first PDCCH occasion.

The method <NUM> continues with operation <NUM> in which the BS <NUM> generates and transmits a random access (RA) response and contention resolution to the UE <NUM>, according to some embodiments. The BS <NUM> further calculates RA-RNTI (Random Access- Radio Network Temporary Identifier) values according to information of the resources on which the random access preambles are transmitted. In some embodiments, the RA-RNTI value can be is determined using the equation below, <MAT> wherein s_id is the index of the first OFDM symbol of the PRACH occasion (<NUM> ≤ s_id <<NUM>); t_id is the index of the first slot of the PRACH occasion in a system frame (<NUM> ≤ t_id < <NUM>); f_id is the index of the first frequency of the PRACH occasion in the frequency domain (<NUM> ≤ f_id < <NUM>); and ul_carrier_id is the UL carrier used for the random access preamble (i.e., <NUM> for NUL carrier and <NUM> for SUL carrier). In some embodiments, f_id and ul_carrier_id each carries information of resources on the frequency domain on which the random access preamble is transmitted; and s_id and t_id each carriers information of resources on the time domain on which the random access preamble is transmitted.

In some embodiments, the RA response comprises a MAC Random Access Response (RAR). In some embodiments, the DCI is transmitted on the PDCCH and the MAC RAR is transmitted on the PDSCH. In some embodiments, before transmitting, the MAC RAR or the DCI is scrambled by the RA-RNTI determined by the BS <NUM>.

In some embodiments, the SFN of a RACH occasion is determined by the BS <NUM> according to the SFN of receiving the random access preamble. In some embodiments, the SFN can be transmitted in one of the following: a MAC RAR and a DCI. For example, <NUM> bits in a MAC RAR or DCI can be used for representing the SFN for transmitting the radio access preamble. <NUM> lower bits of the <NUM> bits can be used for indicating the SFN. For another example, a radio frame in the MAC RAR or DCI can be used for representing the SFN for transmitting the radio access preamble. The radio frame is the SFN mod N, wherein N is an integer.

In some embodiments, the UE <NUM> further calculates RA-RNTI value according to the frequency-domain information of the resource on which the random access preamble is transmitted. When the RA-RNTI scrambled MAC RAR or DCI is received by the UE <NUM> from the BS <NUM> within the time window <NUM>, the UE <NUM> descrambles the MAC RAR or the DCI using the calculated RA-RNTI.

When the MAC-RAR is successfully descrambled, the SFN can be determined and further compared with the SFN used for transmitting the random access preamble. When the value (e.g., the lower bit of the SFN or the SFN mod N) in the MAC RAR or the DCI received by the UE <NUM> from the BS <NUM> in the time window matches the SFN for transmitting the random access preamble by the UE <NUM>, the random access response is received successfully by the UE <NUM>. When the value (e.g., the lower bit of the SFN or the SFN mod N) in the MAC RAR or the DCI received by the UE <NUM> from the BS <NUM> in the time window does not match the SFN for transmitting the random access preamble by the UE <NUM> or the scrambled MAC RAR or DCI is not received by the UE <NUM> from the BS <NUM> within the time window, the random access response is failed.

<FIG> illustrates a method <NUM> of performing a <NUM>-step contention-based Random Access (RACH) procedure in a wireless communication system, according to some embodiments of the present disclosure. In the illustrated embodiment, the wireless communication system comprises a UE <NUM> and a BS <NUM>. It is understood that additional operations may be provided before, during, and after the method <NUM> of <FIG>, and that some other operations may be omitted or only briefly described herein. It should be noted <FIG> is an example for illustration and the <NUM>-step contention-based RACH process of <FIG> is used for discussion purposes. It should be noted that the method <NUM> can be also used in a <NUM>-step contention-based RACH process.

The method <NUM> starts with operation <NUM> in which the first UE <NUM>-<NUM> and the second UE <NUM>-<NUM> each transmits a random access preamble and scheduled transmission to the BS <NUM> according to some embodiments. Before transmitting the random access preamble to the BS <NUM>, the UE <NUM> performs a LBT process on the selected at least one PRACH occasion. In some embodiments, the LBT process comprises sensing interference and bursty arrivals of packets through its transmitters to determine interference level and traffic loads on the uplink carrier. If the LBT process fails, the UE <NUM> restarts the LBT process at the following PRACH occasion on the corresponding uplink carrier until the LBT process passes (i.e., the uplink carrier is available and unoccupied). The first UE <NUM>-<NUM> and the second UE <NUM>-<NUM> then starts first transmissions of random access preambles to the BS <NUM> on the PRACH occasion. In some embodiments, the first message further comprises a MAC CE, wherein the MAC CE is configured to carry at least one of the following: information of the secondary primary cell (e.g., PCI), the information of the serving cell (e.g., ServCellIndex), and the information of the UE <NUM> (e.g., MAC-I), which are discussed in detail below in <FIG>. In some embodiments, the first message further comprises at least one Media Access Control (MAC) Control Element (CE) for at least one of the following: a Cell- Radio Network Temporary Identifier (C-RNTI) MAC CE and a Buffer Status Report (BSR). In some embodiments, the first UE <NUM>-<NUM> and the second UE <NUM>-<NUM> can be differentiated according to the first MAC CE, and at least one of the following MAC CE: the C-RNTI MAC CE and the BSR MAC CE.

The method <NUM> continues with operation <NUM> in which the BS <NUM> generates and transmits a random access (RA) response and contention resolution to the UE <NUM>, according to some embodiments. In some embodiments, the RA response comprises the DCI and a MAC Random Access Response (RAR). In some embodiments, the DCI is transmitted on the PDCCH and the MAC RAR is transmitted on the PDSCH. In some embodiments, the random access response and contention resolution further comprises information determined according to the random access preamble received from the UE <NUM>. For example, during an initial access, the random access response comprises a MAC RAR subheader and a MAC RAR, wherein the MAC RAR comprises timing advance command, UL grant, and temporary C-RNTI; and the contention resolution comprises at least one of the following: ID MAC CE and a RRC setup message.

<FIG> illustrates an exemplary format of a MAC CE subheader <NUM>, in accordance with some embodiments of the present disclosure. In the illustrated embodiment, the MAC CE subheader <NUM> is transmitted on a PDSCH and comprises <NUM> bits <NUM>. In the illustrated embodiment, two reserved fields <NUM> occupying first <NUM> bits <NUM> and a Language Code Identifier (LCID) field <NUM> occupying last <NUM> bits. It should be noted that <FIG> is an exemplary format of the MAC CE subheader and is not intended to be limiting. Any MAC CE subheader with a field for indicating PCI can be used and is within the scope of this invention.

<FIG> illustrates a table <NUM> of LCID values in a MAC CE subheader, in accordance with some embodiments of the present disclosure. In the illustrated embodiment, the table <NUM> comprises <NUM> columns, i.e., a first column <NUM> showing a plurality of indices and a second column <NUM> comprising a plurality of corresponding LCID values. In the illustrated embodiment, the LCID field in the MAC CE subheader occupies <NUM> bits and <NUM> indices. In the illustrated embodiment, an index value of <NUM> indicates a Common Control Channel (CCCH)occupying <NUM> bits; an index value of <NUM>-<NUM> identifies an logical channel; an index of <NUM>-<NUM> is reserved; a value of <NUM> is for indicating a PCI; an index value of <NUM> indicates a CCCH occupying <NUM> bits; an index value of <NUM> indicates a recommended bit rate query; an index value of <NUM> indicates multiple entry Power Headroom Report (PHR) (<NUM> octets); an index value of <NUM> indicates configured grate confirmation; an index value of <NUM> indicates multiple entry PHR (<NUM> octet); and an index value of <NUM> indicates a single entry PHR; an index value of <NUM> indicates C-RNTI; an index value of <NUM> indicates short truncated BSR; an index value of <NUM> indicates long truncated BSR; an index value of <NUM> indicates short BSR; an index value of <NUM> indicates long BSR; and an index value of <NUM> indicates Padding.

<FIG> illustrates an exemplary format of a MAC CE <NUM>, in accordance with some embodiments of the present disclosure. In the illustrated embodiment, the MAC CE <NUM> is transmitted on a PDSCH and comprises <NUM> octets <NUM>. In the illustrated embodiments, <NUM> reserved fields <NUM> occupying first <NUM> bits <NUM> in a first octet <NUM>-<NUM>, a physical cell ID <NUM> occupies last <NUM> bits <NUM> of the first octet <NUM>-<NUM> and <NUM> bits <NUM> of a second octet <NUM>-<NUM>. In some embodiments, the physical cell ID field <NUM> occupying at least <NUM> bits is configured to carry the PCI of a UE <NUM>. In some embodiments, the PCI and the C-RNTI are used to differentiate different UE <NUM>. It should be noted that <FIG> is an exemplary format of the MAC CE and is not intended to be limiting. Any MAC CE with a field for indicating the PCI can be used and is within the scope of this invention.

<FIG> illustrates an exemplary format of a MAC CE <NUM>, in accordance with some embodiments of the present disclosure. In the illustrated embodiment, the MAC CE <NUM> is transmitted on a PDSCH and comprises <NUM> octet <NUM>. In the illustrated embodiments, <NUM> reserved fields <NUM> occupying first <NUM> bits <NUM>, and a serving Cell index (ServCellIndex) field <NUM> occupies last <NUM> bits <NUM>. In some embodiments, the ServCellIndex field <NUM> occupying <NUM> bits is configured to carry serving cell information of a UE <NUM>. In some embodiments, the serving cell information and the C-RNTI are used to differentiate different UE <NUM>. It should be noted that <FIG> is an exemplary format of the MAC CE and is not intended to be limiting. Any MAC CE with a field for indicating the serving cell information can be used and is within the scope of this invention.

<FIG> illustrates an exemplary format of a MAC CE <NUM>, in accordance with some embodiments of the present disclosure. In the illustrated embodiment, the MAC CE <NUM> is transmitted on a PDSCH and comprises <NUM> octets <NUM>. In the illustrated embodiments, a MAC-I field <NUM> occupies <NUM> bits <NUM> of the <NUM> octets. In some embodiments, the MAC-I field <NUM> is configured to carry information of a UE <NUM>. In some embodiments, the information of the UE 104in the MAC-I field <NUM> is used to differentiate different UE <NUM>. It should be noted that <FIG> is an exemplary format of the MAC CE and is not intended to be limiting. Any MAC CE with a field for indicating the information of the UE <NUM> can be used and is within the scope of this invention.

<FIG> illustrates a method <NUM> for a discontinuous reception mode (DRX) process, in accordance with some embodiments of the present disclosure. In the illustrated embodiment, the wireless communication system comprises a UE <NUM> and a BS <NUM>. In the illustrated embodiment, the UE <NUM> is in a DRX mode, in which the UE <NUM> only performs a Physical Downlink Control Channel (PDCCH) blind detection during an active time and turns off monitoring PDCCH during a non-active time. In some embodiments, the active time and non-active time appear alternatively and periodically. When no service is detected during an active time and when the active time window ends, the UE <NUM> enters a following non-active time. It is understood that additional operations may be provided before, during, and after the method <NUM> of <FIG>, and that some other operations may be omitted or only briefly described herein. It should be noted <FIG> is an example for illustration and discussion purposes.

The method <NUM> starts with operation <NUM> in which at least one DRX parameter is configured to the UE <NUM> from the BS <NUM> according to some embodiments. In some embodiments, the at least one DRX parameter comprises a period of a DRX process, a DRX inactive timer, an active time and a non-active time. In some embodiments, the at least one DRX parameter is configured by the BS <NUM> to the UE <NUM> through a RRC reconfiguration process.

The method <NUM> continues with operation <NUM> in which the UE <NUM> starts the DRX process according to some embodiments. In some embodiments, the UE <NUM> determines to enter an active time according to the at least one DRX parameter and service scheduling situation of the BS <NUM>. In some embodiments, a first active timer indicated in the DRX parameter is started at time t0 <NUM>-<NUM> when the UE <NUM> starts the DRX process and the first active timer has a window size <NUM>-<NUM> which terminates at time t1 <NUM>-<NUM>.

The method <NUM> continues with operation <NUM>, in which a first message is received by the UE <NUM> from the BS <NUM> according to some embodiments. In some embodiments, the first message is a media access control message, e.g., MAC PDU, in a format of a data-indication MAC control element (CE). In some embodiments, the first message is received at time t2 <NUM>-<NUM> before the termination of the first active timer. In some embodiments, the first message is transmitted on a PDSCH. In some embodiments, the data-indication MAC CE is for an indication of pending data for transmission from the BS <NUM> to the UE <NUM> so as to start a second active timer before an expiration of the first active timer. In some embodiments, the data-indication MAC CE is identified in the MAC PDU subheader with LCID, which is discussed in <FIG> below. In some embodiments, the second active timer has a window size <NUM>-<NUM>, wherein the window size of the second active timer can be one of the following: the DRX inactive timer configured in the at least one DRX parameter and a second active timer configured by the BS <NUM>. In some embodiments, after receiving the first message, the UE <NUM> remains active for receiving the pending data from the BS <NUM> according to some embodiments. In some embodiments, when the UE <NUM> receives the data-indication MAC CE in the first message, the UE <NUM> further performs one of the following: restarting the DRX inactive timer and starting a new timer, so as to continue with the PDCCH blind detection.

<FIG> illustrates an exemplary format of a MAC CE subheader <NUM>, in accordance with some embodiments of the present disclosure. In the illustrated embodiment, the MAC CE subheader <NUM> is transmitted on a PDSCH and comprises <NUM> bits <NUM>. In the illustrated embodiment, two reserved fields <NUM> occupying first <NUM> bits <NUM> and a LCID field <NUM> occupying last <NUM> bits. It should be noted that <FIG> is an exemplary format of the MAC CE subheader and is not intended to be limiting. Any MAC CE subheader with a field for indicating PCI can be used and is within the scope of this invention.

<FIG> illustrates a table <NUM> of Language Code Identifier (LCID) values in a MAC CE subheader, in accordance with some embodiments of the present disclosure. In the illustrated embodiment, the table <NUM> comprises <NUM> columns, i.e., a first column <NUM> showing a plurality of indices and a second column <NUM> comprising a plurality of corresponding LCID values. In the illustrated embodiment, the LCID field in the MAC CE subheader occupies <NUM> bits and <NUM> indices. In the illustrated embodiment, an index value of <NUM> indicates a CCCH occupying <NUM> bits; an index value of <NUM>-<NUM> identifies an logical channel; an index of <NUM>-<NUM> is reserved; an index value of <NUM> is for data indication command; an index value of <NUM> indicates recommended bit rate; an index value of <NUM> indicates semi-persistent zero power channel state information-reference signal (SP ZP CSI-RS) Resource Set Activation/Deactivation; an index value of <NUM> indicates PUCCH spatial relation Activation/Deactivation; a value of <NUM> indicates semi-persistent sounding reference signal (SP SRS) Activation/Deactivation; a value of <NUM> indicates SP CSI reporting on PUCCH Activation/Deactivation; an index value of <NUM> indicates a Transmission Configuration Indication (TCI)State Indication for UE-specific PDCCH; an index value of <NUM> indicates TCI states Activation/Deactivation for UE-specific PDSCH; an index value of <NUM> indicates Aperiodic CSI Trigger State Subselection; an index value of <NUM> indicates SP CSI-RS/ semi-persistent channel state information interference measurement (CSI-IM) Resource Set Activation/Deactivation; an index value of <NUM> indicates Duplication Activation/Deactivation; an index value of <NUM> SCell Activation/Deactivation (Four Octets); an index value of <NUM> indicates SCell Activation/Deactivation (One Octet); an index value of <NUM> indicates Long DRX Command; an index value of <NUM> indicates DRX command; an index value of <NUM> indicates Timing Advance Command; an index value of <NUM> indicates UE Contention Resolution Identity; and an index value of <NUM> indicates Padding.

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.

A person of ordinary skill in the art would further appreciate that any of the some 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, which can be designed using source coding or some other technique), various forms of program or design code incorporating instructions (which can be referred to herein, for convenience, as "software" or a "software module), or combinations of both. Whether such functionality is implemented as hardware, firmware or software, or a combination of these technique, 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 should not be interpreted as causing a departure from the scope of the present disclosure.

Claim 1:
A method performed by a wireless communication device (<NUM>), comprising:
receiving first information from a wireless communication node (<NUM>), wherein the first information comprises information of a plurality of time windows for receiving a second message;
transmitting a first message to the wireless communication node (<NUM>) using a System Frame Number, SFN, for transmitting the first message and wherein the SFN for transmitting the first message is used to indicate one of the time windows of the plurality of time windows;
receiving the second message from the wireless communication node (<NUM>) within a time window of the plurality of time windows based on the first information,
wherein the second message comprises an SFN received in a Media Access Control Random Access Response, MAC RAR, or a Downlink Control Information, DCI;
comparing the SFN in the MAC RAR or the DCI with the SFN used for transmitting the first message; and
determining that the second message is successfully received when the SFN in the MAC RAR or the DCI received within the time window matches the SFN used for transmitting the first message.