Patent Description:
In a wireless communication system such as NR (new radio), a random access procedure such as <NUM>-step random access procedure is needed for a UE to get access to the communication system. Before initiating random access procedure, UE needs to go through an initial synchronization process. For example, the UE needs to detect a synchronization signal (SS) such as Primary Synchronization Signals (PSSs) and Secondary Synchronization Signals (SSSs), etc. Then the UE decodes broadcasted system information. The next step is known as the random access procedure.

In a <NUM>-step random access procedure as shown in <FIG>, the UE transmits a PRACH (physical random access channel) preamble (msg1) in an uplink at step <NUM>. The base station such as next generation NodeB (gNodeB or gNB) replies with a RAR (Random Access Response, msg2) at step <NUM>. The RAR may carry following information: temporary C-RNTI (cell radio network temporary identity); Timing Advance Value; and Uplink Grant Resource. The UE then transmits a RRC (radio resource control) connection request message (msg3) on a physical uplink shared channel (PUSCH) at step <NUM>. The RRC connection request message may contain following information: UE identity and connection establishment cause. The UE transmits PUSCH (msg3) after receiving a timing advance command in the RAR, allowing PUSCH to be received with a timing accuracy within the cyclic prefix. Without this timing advance, a very large CP (Cyclic-Prefix) would be needed in order to be able to demodulate and detect PUSCH, unless the system is applied in a cell with very small distance between UE and the base station. The base station responds with contention resolution message (msg4) to UE at step <NUM>. Since NR will also support larger cells with a need for providing a timing advance to the UE, the <NUM>-step random access procedure is needed for random access procedure.

"<NPL>, discusses details of the MsgA resource selection procedure.

A <NUM>-step RACH (random access channel) work item has been approved in 3rd generation partnership project (3GPP) meeting. The <NUM>-step random access procedure as shown in <FIG> can complete initial access in only two steps. As shown in <FIG>, at step <NUM>, UE sends a message A (msgA) including PRACH preamble on a PRACH occasion together with higher layer data such as RRC connection request possibly with some small payload on PUSCH. At step <NUM>, the base station such as gNB sends a message B (msgB) such as RAR including one or more of UE identifier assignment, timing advance information, and contention resolution message, etc..

In NR, the time and frequency resource on which a PRACH preamble is transmitted is defined as a PRACH occasion. The PRACH occasion may be also called RACH occasion, or RA occasion, or in short RO. And the RO used for the transmission of the PRACH preambles in <NUM>-step random access procedure is called <NUM>-step RO, while the RO used for the transmission of the PRACH preambles in <NUM>-step random access procedure is called <NUM>-step RO.

NR release (Rel) <NUM> of 3GPP supports one-to-one, one-to-many, and many-to-one association between Synchronization Signal Block and PRACH occasions. In addition, there may be a mapping between SSB (synchronization signal and physical broadcast channel block) and PRACH preambles. In NR, the SSB may include PSS, SSS and PBCH (Physical Broadcast Channel). When UE selects an available SSB beam, a PRACH occasion associated with the SSB and a PRACH preamble in the set of one or more PRACH preambles mapped to this SSB will be selected for the random access, then when the gNB detects the PRACH preamble, the selected SSB beam for the UE is known according to the association so that selected beam can be used for transmitting signals to or receiving signals from the UE.

In recent NR RAN2 meeting, below agreements have been made to support the msgB multiplexing messages of multiple UEs, which is transmitted in a single PDSCH (Physical Downlink Shared Channel).

In the <NUM>-step random access procedure, no agreements have yet been met regarding SSB selection and reporting.

Although the combining of messages for multiple UEs in a same msgB is supported in <NUM>-step random access procedure, there are some concerns in the <NUM>-step random access procedure. For example, one issue is that when multiple SSBs are mapped to one RO, and if the msgB transmissions for these UEs correspond to different SSB beams, no way to know which SSB beam should be used for the combined transmission of the msgB. Another issue is it is unsettled which RNTIs (radio network temporary identities) and/or MCS (modulation coding scheme) should be used for this kind of msgB transmissions and monitoring needs to be determined.

To overcome or mitigate at least one of the above mentioned problems or other problems or provide a useful solution, some embodiments of the present disclosure propose methods on how to group the UEs in a same msgB PDSCH transmission. Some embodiments provide a solution for indication of SSB by the UE. Some embodiments provide a solution for determining the beam to be used for the combined msgB transmission. Some embodiments provide a solution for determining the RNTI to be used for the combined msgB transmission/monitoring. Some embodiments provide a solution for determining the MCS to be used for the combined msgB transmissions.

Embodiments of the disclosure are as provided in the claims. For the avoidance of doubt, the claims define the scope of the disclosure.

As used herein, the term "network" refers to a network following any suitable communication standards such as the first generation (<NUM>), <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> communication protocols, and/or any other communication standards either currently known or to be developed in the future. In the following description, the terms "network" and "system" can be used interchangeably. Furthermore, the communications between a terminal device and a network node in the communication system may be performed according to any suitable generation communication protocols, including, but not limited to, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> communication protocols, and/or any other protocols either currently known or to be developed in the future. In addition, the specific terms used herein do not limit the present disclosure only to the communication system related to the specific terms, which however can be more generally applied to other communication systems.

The term "base station" refers to an access network device in a communication network via which a terminal device accesses to the network and receives services therefrom. For example, the base station (BS) may comprise, but not limited to, an Integrated Access and Backhaul (IAB) node, an access point (AP), a multi-cell/multicast coordination entity (MCE), etc. The BS may be, for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a next generation NodeB (gNodeB or gNB), a remote radio unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth.

The term "terminal device" refers to any end device that can access a communication network and receive services therefrom. By way of example and not limitation, in the wireless communication network, the terminal device may refer to a mobile terminal, a user equipment (UE), a terminal device, or other suitable devices. The terminal device may be, for example, a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a portable computer, an image capture device such as a digital camera, a gaming terminal device, a music storage and a playback appliance, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet, a wearable device, a personal digital assistant (PDA), a portable computer, a desktop computer, a wearable device, a vehicle-mounted wireless device, a wireless endpoint, a mobile station, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a USB dongle, a smart device, a wireless customer-premises equipment (CPE) and the like. In the following description, the terms "terminal device", "terminal", "user equipment" and "UE" may be used interchangeably. As one example, a UE may represent a terminal device configured for communication in accordance with one or more communication standards promulgated by the 3GPP, such as 3GPP' LTE standard or NR standard. As used herein, a "user equipment" or "UE" may not necessarily have a "user" in the sense of a human user who owns and/or operates the relevant device. In some embodiments, a terminal device may be configured to transmit and/or receive information without direct human interaction. For instance, a UE may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the wireless communication network. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but that may not initially be associated with a specific human user.

As yet another example, in an Internet of Things (IOT) scenario, a terminal device may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another terminal device and/or network equipment. The UE may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as a machine-type communication (MTC) device. As one particular example, the terminal device may be a UE implementing the 3GPP narrow band internet of things (NB-IoT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances, for example refrigerators, televisions, personal wearables such as watches etc. In other scenarios, a UE may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.

As used herein, a downlink, DL, transmission refers to a transmission from a network device to a terminal device, and an uplink, UL, transmission refers to a transmission in an opposite direction.

It is noted that these terms as used in this document are used only for ease of description and differentiation among nodes, devices or networks etc. With the development of the technology, other terms with the similar/same meanings may also be used.

It is noted that though the embodiments are mainly described in the context of <NUM>-step random access procedure and NR, they are not limited to this but can be applied to any suitable random access procedure and network.

<FIG> shows a flowchart of a method <NUM> according to an embodiment of the present disclosure, which may be performed by an apparatus implemented in or at or communicatively coupled to a UE or any other entity having similar functionality. As such, the UE may provide means for accomplishing various parts of the method <NUM> as well as means for accomplishing other processes in conjunction with other components.

At block <NUM>, the UE transmits a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) to a base station. As described above, before initiating random access procedure, the UE may need to go through an initial synchronization process. For example, the UE detects a synchronization signal (SS) such as Primary Synchronization Signals (PSSs) and Secondary Synchronization Signals (SSSs). Then the UE decodes the broadcasted system information such as PBCH, RMSI (Remaining Minimum System Information), OSI(Other System Information), etc..

The first message may be referred to as msgA herein. In an embodiment, the first message may be a layer <NUM> message. The data on the USCH may include any suitable information. For example, the data on the USCH may include higher layer data such as RRC connection request possibly with some small payload on PUSCH. In an embodiment, the channel structure of msgA may be PRACH preamble and PUSCH carrying payload. In an embodiment, the SSB may correspond to SS/PBCH block in NR. In an embodiment, the first message may also include the equivalent contents of msg3 of <NUM>-step random access procedure. In an embodiment, the first message may reuse the 3GPP Rel <NUM> NR PUSCH including Rel-<NUM> DMRS (Demodulation Reference Signal) for transmission of payload of msgA.

The RACH preamble may be any suitable preamble used for random access procedure. For example, the RACH preamble may reuse the 3GPP Release <NUM> NR PRACH Preambles design. In an embodiment, there may be a mapping between the PRACH preamble and the time-frequency resource of PUSCH in msgA+ DMRS. In an embodiment, there may be any suitable supported modulation coding scheme(s) (MCS(s)) and time-frequency resource size(s) of PUSCH in msgA. In an embodiment, there may be any suitable power control of PUSCH of msgA. In an embodiment, UCI (uplink control information) may be included in msgA.

Since the reporting of SSB in the <NUM>-step random access procedure is only explicitly done by SSB to RO and preamble mapping, it is only possible to indicate one single SSB by the preamble transmission. This makes it difficult for the base station such as gNB to know if a UE indicating a beam corresponding to e.g. SSB1 would be able to receive a msgB transmitted on a beam corresponding to e.g. SSB2. An improved SSB reporting by the UE can be performed by reporting more than one beam or SSB in the msgA transmission. There may be many methods to report more than one SSB in the <NUM>-step random access procedure.

In an embodiment, the data may include information of at least one synchronization signal and physical broadcast channel block (SSB) with a signal measured metric satisfying a criterion. The signal measured metric may be any suitable signal measured metric measured based on downlink signals. In an embodiment, the signal measured metric may be reference signal received power (RSRP), or reference signal received quality (RSRQ), or signal-to-interference-plus-noise ratio (SINR) measured based on a downlink signal. The reference signal can be any suitable reference signal such as synchronization signal reference signal, etc. In an embodiment, the signal may be a layer <NUM> signal. For example, the data may include information of at least one SSB with a synchronization signal RSRP(SS-RSRP) above rsrp-ThresholdSSB. The rsrp-ThresholdSSB is described in 3GPP TS <NUM> V15.

In an embodiment, the criterion may be a threshold and the signal measured metric satisfying the criterion may include the signal measured metric larger than or no less than the threshold.

In an embodiment, at least one SSB with the signal measured metric satisfying the criterion may include a subset or set of all SSBs with the signal measured metric satisfying the criterion. The set of all SSBs with the signal measured metric satisfying the criterion may be determined by measuring signal measured metric of a candidate set of SSBs and comparing the signal measured metric to a corresponding criterion. The criterion may be predefined or indicated in at least one of system information and dedicated higher layer control signaling. For example, the selected preamble and/or RO may indicate the best beam. The data on the USCH may indicate a subset of all SSBs with SS-RSRP above rsrp-ThresholdSSB. The set of all SSBs with SS-RSRP above rsrp-ThresholdSSB may be determined by measuring the power of a candidate set of SSBs and comparing the measured power to rsrp-ThresholdSSB. In another example, a different threshold than rsrp-ThresholdSSB may be used, and this threshold may be predefined or indicated in at least one of system information and dedicated higher layer control signaling.

In an embodiment, the at least one SSB with the signal measured metric satisfying the criterion includes the SSBs that are associated with the RACH occasion. For example, the at least one SSB corresponds to the SSBs that are associated with the RACH occasion. An advantage of this embodiment is that a fixed set of SSBs are associated with each RACH occasion, and since an RNTI can be used to identify at least the RACH occasion, the signaling only needs to identify the fixed set of SSBs associated with the RO, which can reduce signaling overhead compared to when the at least one SSB are from multiple ROs. For example, each SSB can be identified by one bit in the signaling, and if the signal measured metric of a SSB satisfies the criterion, the corresponding bit may be set to <NUM>, otherwise the corresponding bit may be set to <NUM>. In some embodiments, the association between ROs and the preambles in ROs may be performed according to subclause <NUM> of 3GPP TS <NUM> V15.

In an embodiment, the at least one SSB with the signal measured metric satisfying the criterion includes the SSBs in a set of SSBs with the signal measured metric satisfying the criterion except the SSB indicated by the RACH preamble and the RACH occasion. For example, the at least one SSB can be the SSBs in the set of SSBs with SS-RSRP above rsrp-ThresholdSSB except the SSB indicated by the preamble and RO.

In an embodiment, the at least one SSB with the signal measured metric satisfying the criterion includes all SSBs in a set of SSBs with the signal measured metric satisfying the criterion. For example, all SSBs in the set of SSBs with SS-RSRP above rsrp-ThresholdSSB are indicated in the PUSCH of msgA. The set of SSBs with SS-RSRP above rsrp-ThresholdSSB may be determined by measuring the power of a candidate set of SSBs and comparing the measured power to rsrp-ThresholdSSB.

In various embodiments, the criterion may be predefined (such as rsrp-ThresholdSSB) or indicated in system information and/or a non-access stratum layer control signaling. When the criterion is indicated in system information and/or a non-access stratum layer control signaling, the criterion may be updated.

In an embodiment, the at least one SSB is indicated by using a list sorted by the signal measured metric. For example, the set of SSBs with SS-RSRP above a received power threshold are indicated in the PUSCH of msgA using a sorted list, for example sorted by the SS-RSRP. The threshold may be rsrp-ThresholdSSB or a different threshold than rsrp-ThresholdSSB. The threshold may be indicated in at least one of system information and dedicated higher layer control signaling. In an embodiment, each element of the sorted list includes respective index of the at least one SSB. For example, each element of the list may include an index of the SSB on which the SS-RSRP was measured. In an embodiment, each element of the sorted list includes an indication of a value of the signal measured metric of the at least one SSB. For example, an element of the list may include an indication of a value of the SS-RSRP measured on the SSB.

In an embodiment, the at least one SSB is indicated by using a bitmap. For example, the set of SSBs with SS-RSRP above a received power threshold are indicated in the PUSCH of msgA using a bitmap. In an embodiment, each bit in the bitmap corresponds to only one SSB and all bits in the bitmap correspond to one RO. In another embodiment, each bit in the bitmap corresponds to only one SSB and all bits in the bitmap corresponds to all SSBs used in the base station. In still another embodiment, <NUM> bit in the bitmap can be mapped to a subset of the considered SSBs, and all bits in the bitmap are mapped to a completed set of the considered SSBs.

In an embodiment, the RACH preamble and the RACH occasion are selected based on a mapping of the SSB to the RACH preamble and the RACH occasion. For example, a detailed mapping rule is specified in section <NUM> of 3GPP TS <NUM> V15. The UE will select an SSB with SS-RSRP above rsrp-ThresholdSSB (if such SSB is available). The selected SSB will be indicated to the gNB either by the selected preamble or by the PRACH occasion (RO). This indication will enable the gNB to choose a suitable DL beam for the RAR transmission. The SSB selection and the preamble transmission (and mapping RO to SSB) may be similar to those as specified in subclause <NUM>. <NUM> of 3GPP TS <NUM> V15.

In an embodiment, the RACH preamble and the RACH occasion are selected based on a predefined rule. For example, when the set of SSBs with SS-RSRP above a received power threshold are indicated in PUSCH of msgA, the SSB to preamble and RO mapping may be removed. In this case, the RACH preamble and the RACH occasion may be selected based on a predefined rule, which can give more available ROs and preambles for random access indicating a specific SSB. The predefined rule may be random selection rule or any other suitable selection rule.

In an embodiment, the RACH is a physical random access channel (PRACH). In an embodiment, the USCH is a physical uplink shared channel (PUSCH).

At block <NUM>, the UE receives a second message as a response to the first message. The second message such as msgB may include any suitable information such as the equivalent contents of msg2 and msg4 of <NUM>-step random access procedure. The second message may be a layer <NUM> message. In an embodiment, for the response to a successfully decoded msgA, the msgB should include TA (timing advance) command, contention resolution ID, etc. For the response to a msgA failed to be decoded, the msgB can be a fall-back message, or even a normal RAR(msg2).

In an embodiment, the second message may include one or more of the UE's assigned identifier, timing advance information and contention resolution message.

In an embodiment, the second message can multiplex respective response to respective first message of the UE and at least one other UE. In this case, the second message further includes the respective response to the respective first message of at least one other UE. For example, for CCCH, for success or fallback RAR, MsgB can multiplex messages for multiple UEs and msgB is transmitted in one PDSCH. In another embodiment, MsgB containing the success RAR shall not be multiplexed with the legacy <NUM>-step RACH RAR in the same MAC PDU.

Which UEs can be multiplexed in the second message can be determined in various ways. In an embodiment, UEs having a same determined MCS can be multiplexed in the second message. In an embodiment, UEs having a certain common SSB with a signal measured metric satisfying the criterion can be multiplexed in the second message. In an embodiment, UEs transmitting RACH preambles mapped to a same SSB can be multiplexed in the second message. In an embodiment, UEs having a same downlink preferred beam can be multiplexed in the second message. The UE's preferred beam can be indicated to the base station in various ways. For example, when UE detects a best SSB beam (i.e., the preferred beam), a PRACH preamble in the set of one or more PRACH preambles mapped to this SSB will be selected for the random access, then when the base station such as gNB detects the PRACH preamble, the best SSB beam for this UE is known indirectly so that best beams can be used for transmitting signals to or receiving signals from this UE. In this case, the UE's preferred beam can correspond to the best SSB beam. In other embodiments, the UE's preferred beam can correspond to the SSB beam with the best signal measured metric (such as the highest RSRP, or the best RSRQ, or the biggest SINR) satisfying the criterion.

A beam for the second message may be determined for example by the base station in various ways. In an embodiment, a beam for the second message may be a common downlink beam of the UE and the at least one other UE. For example, the beam for the combined msgB transmission can be a common downlink beam preferred by the UEs, this requires the combination is only used in a group of UEs with at least one same downlink preferred beam. For example, when <NUM> preambles are allocated, and each RO is mapped by <NUM> SSBs and <NUM> preambles are mapped to each SSB, then only the UEs transmitting some of the <NUM> preambles mapped to one SSB can be combined in the msgB.

In an embodiment, a beam for the second message may be a beam covering at least one of the UE's preferred beam and the at least one other UE's preferred beam. For example, the beam for the combined msgB transmission can be a wide beam covering at least one of the UE's preferred beam and the at least one other UE's preferred beam.

In an embodiment, a beam for the second message may be a preferred beam of a UE with a higher priority between the UE and the at least one other UE. For example, the beam used for the combined msgB transmission can be determined based on the priority of the data of the UEs. For example, the preferred beam for the transmission of the data for UE with higher priority can be used. The priority can be based on the random access type, e.g. <NUM>-step RA is prioritized. The priority can be based on the service type, e.g. the uRLLC (Ultra Reliable Low Latency Communications) UE is prioritized.

In an embodiment, a beam for the second message may be a beam randomly selected from the UE's preferred beam and the at least one other UE's preferred beam. For example, the beam for the second message is randomly selected from the set of beams preferred by the group of UEs with data combined in one msgB PDSCH.

In an embodiment, a beam for the second message may be determined based on a common SSB from the plurality of SSBs reported by the UEs. For example, UEs that have reported a certain common SSB in the sets (one from each UE) of SSBs with SS-RSRP above rsrp-ThresholdSSB are selected to be combined in PDSCH of one msgB.

A radio network temporary identifier (RNTI) for the second message may be determined for example by the base station in various ways. In an embodiment, the RNTI for the second message may be a common RNTI of the UE and the at least one other UE. The common RNTI may be determined in various ways. In an embodiment, the common RNTI is computed based on a same RACH occasion when the at least one other UE and the UE having the first message transmitted on the same RACH occasion. In an embodiment, the common RNTI is a group RNTI defined for the UE and the at least one other UE. In an embodiment, the common RNTI is indicated in respective first message from the UE and the at least one other UE. For example, the RNTI used for the combined msgB transmission is a common RNTI for the group of UEs combined in the msgB transmission. The common RNTI can be obtained by one or more of the following methods: the group of UEs are those that have preambles transmitted on the same RACH occasion so that a common random access RNTI (RA-RNTI) or a RA-RNTI related common RNTI can be obtained; separately defined group RNTI is used for the group of UEs combined in one msgB transmission; the common RNTI to be used is indicated in the msgA PUSCH from the UEs.

In an embodiment, the RNTI for the second message may be a UE specific RNTI of a UE with a higher priority between the UE and the at least one other UE. In an embodiment, the RNTI for the second message may be a UE specific RNTI randomly selected from the UE's UE specific RNTI and the at least one other UE's UE specific RNTI. In an embodiment, the RNTI for the second message may be a UE specific RNTI determined based on a measurement on uplink signals from the UE and the at least one other UE or a measurement by the UE and the at least one other UE on downlink signals. In an embodiment, when the RNTI for the second message is the UE specific RNTI, a system frame number is included in downlink control information to indicate whether a corresponding second message is for the UE. For example, the RNTI used for the msgB transmission is still UE specific msgB RNTI, multiple PDCCHs (Physical Downlink Control Channels) may be transmitted to schedule multiple UEs on the same PDSCH. Which RNTI is used for the PDSCH data scrambling can be indicated in the corresponding L1 signaling, and this can be determined with one or more of the following methods: randomly selected; RA type, e.g. <NUM>-step RA UEs can be prioritized; service type, e.g. uRLLC UEs can be prioritized; the measurement on the received signal from the UE or the measurement by the UE on the downlink signals, e.g. the signal strength, the signal quality.

In an embodiment, the UE specific RNTI is a random access RNTI (RA-RNTI). The RA-RNTI may be similar to the RA-RNTI as described in 3GPP TS <NUM> V15. For example, the RNTI used for the msgB transmission is still UE specific msgB RNTI, multiple PDCCHs may be transmitted to schedule multiple UEs on the same PDSCH. A SFN (system frame number) information can be included in the DCI (downlink control information) to indicate whether a corresponding PDSCH is for the UE. So that the RA-RNTI can be used by more than one UEs with preambles transmitted on different system frames.

In an embodiment, a modulation coding scheme (MCS) for the second message may be determined for example by the base station as one of MCS corresponding to a lowest signal/link quality between the UE's signal/link quality and the at least one other UE's signal/link quality; MCS corresponding to a signal/link quality of a UE with a higher priority between the UE and the at least one other UE; and MCS with the lowest coding rate and/or the lowest modulation order selected from a group of MCSs determined for the UE and the at least one other UE. For example, an MCS is normally determined by the network based on the quality of the UE, there may be various methods for determining one common MCS for the combined msgB transmission which involves a group of UEs. For example, same MCS is required for the combined UEs in the same msgB transmission, and the same MCS (and also the MCS table) can be determined based on the UE with one or more of the following properties: lowest signal/link quality; <NUM>-step RA or <NUM>-step RA; uRLLC service or eMBB service. In an embodiment, the lowest MCS is selected from the group of MCS values determined for the group of UEs. In some embodiments, only the group of UEs with same determined MCS are combined in one msgB transmission, then the same determined MCS is selected.

<FIG> shows a flowchart of a method <NUM> according to another embodiment of the present disclosure, which may be performed by an apparatus implemented in or at or communicatively coupled to a UE or any other entity having similar functionality. As such, the UE may provide means for accomplishing various parts of the method <NUM> as well as means for accomplishing other processes in conjunction with other components. For some parts which have been described in the above embodiments, detailed description thereof is omitted here for brevity.

At block <NUM>, the UE selects a synchronization signal and physical broadcast channel block (SSB) with a signal measured metric satisfying a criterion.

At block <NUM>, the UE transmits a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) to a base station. The RACH preamble and the RACH occasion are selected based on a mapping of the SSB to the RACH preamble and the RACH occasion; and.

At block <NUM>, the UE receives a second message from the base station as a response to the first message.

In an embodiment, the data comprises information indicating at least one SSB with the signal measured metric satisfying the criterion.

In an embodiment, the at least one SSB indicated by the first message includes one or more SSBs that are associated with the RACH occasion.

In an embodiment, the at least one SSB indicated by the first message includes the SSBs in a set of SSBs with the signal measured metric satisfying the criterion except the SSB indicated by the RACH preamble and the RACH occasion.

In an embodiment, the at least one SSB is indicated by a list sorted by the signal measured metric or a bitmap.

In an embodiment, the RACH is a physical random access channel (PRACH), the USCH is a physical uplink shared channel (PUSCH) and the signal measured metric is reference signal received power (RSRP), or reference signal received quality (RSRQ), or signal-to-interference-plus-noise ratio (SINR) measured based on a downlink signal.

In an embodiment, the criterion is that the signal measured metric larger than or no less than a threshold.

In an embodiment, the second message can multiplex respective response to respective first message of the UE and at least one other UE.

In an embodiment, the UE and the at least one other UE have a same determined MCS are multiplexed in the second message; have a certain common SSB with a signal measured metric satisfying the criterion are multiplexed in the second message; transmit RACH preambles mapped to a same SSB are multiplexed in the second message; and/or have a same downlink preferred beam are multiplexed in the second message.

In an embodiment, a beam for the second message is one of a common downlink beam of the UE and the at least one other UE; a beam covering at least one of the UE's preferred beam and the at least one other UE's preferred beam; a preferred beam of a UE with a higher priority between the UE and the at least one other UE; and a beam randomly selected from the UE's preferred beam and the at least one other UE's preferred beam.

In an embodiment, a radio network temporary identifier (RNTI) for the second message is one of a common RNTI of the UE and the at least one other UE; a UE-specific RNTI with a higher priority between the UE and the at least one other UE; a UE-specific RNTI randomly selected from the UE's UE specific RNTI and the at least one other UE's UE specific RNTI; and a UE-specific RNTI determined based on a measurement on uplink signals from the UE and the at least one other UE or a measurement by the UE and the at least one other UE on downlink signals.

In an embodiment, the common RNTI is computed based on a same RACH occasion when the at least one other UE and the UE having the first message transmitted on the same RACH occasion, or the common RNTI is a group RNTI defined for the UE and the at least one other UE; or the common RNTI is indicated in respective first message from the UE and the at least one other UE.

<FIG> shows a flowchart of a method <NUM> according to an embodiment of the present disclosure, which may be performed by an apparatus implemented in or at or communicatively coupled to a base station or any other entity having similar functionality. As such, the base station may provide means for accomplishing various parts of the method <NUM> as well as means for accomplishing other processes in conjunction with other components. For some parts which have been described in the above embodiments, detailed description thereof is omitted here for brevity.

At block <NUM>, the base station receives a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) from a user equipment (UE), wherein the data includes information of at least one synchronization signal and physical broadcast channel block (SSB) with a signal measured metric satisfying a criterion. For example, the UE can transmit the first message at block <NUM> of <FIG>, then the base station can receive the first message.

At block <NUM>, the base station transmits a second message as a response to the first message. For example, the second message can only include the response to the first message of the UE. In another example, when the second message is used for multiplexing respective response to respective first message of multiple UEs, the second message can further include the respective response to the first message of at least one other UE.

In an embodiment, the base station can multiplex respective response to respective first message of the UE and at least one other UE in the second message as describe above.

In an embodiment, the base station can determine a beam for the second message as describe above. In an embodiment, the base station can determine a radio network temporary identifier (RNTI) for the second message as describe above. In an embodiment, the base station can determine a modulation coding scheme (MCS) for the second message as describe above.

At block <NUM>, the base station receives a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) from a user equipment (UE). For example, when the data includes information of at least one synchronization signal and physical broadcast channel block (SSB) with a signal measured metric satisfying a criterion, the UE can transmits the first message at block <NUM> of <FIG>, then the base station can receive the first message. In another example, the data may not include information of at least one synchronization signal and physical broadcast channel block (SSB) with a signal measured metric satisfying a criterion.

At block <NUM>, the base station transmits a second message as respective response to respective first message of the UE and at least one other UE. In this embodiment, the second message can multiplex respective response to respective first message of the UE and at least one other UE. The base station may determine a beam for the second message as one of a common downlink beam of the UE and the at least one other UE; a beam covering at least one of the UE's preferred beam and the at least one other UE's preferred beam; a preferred beam of a UE with a higher priority between the UE and the at least one other UE; and a beam randomly selected from the UE's preferred beam and the at least one other UE's preferred beam.

In an embodiment, the base station can determine a radio network temporary identifier (RNTI) for the second message as describe above. In an embodiment, the base station can determine a modulation coding scheme (MCS) for the second message as described above.

At block <NUM>, the base station transmits a second message as respective response to respective first message of the UE and at least one other UE. In this embodiment, the second message can multiplex respective response to respective first message of the UE and at least one other UE. The base station may determine a radio network temporary identifier (RNTI) for the second message as one of a common RNTI of the UE and the at least one other UE; a UE specific RNTI of a UE with a higher priority between the UE and the at least one other UE; a UE specific RNTI randomly selected from the UE's UE specific RNTI and the at least one other UE's UE specific RNTI; and a UE specific RNTI determined based on a measurement on uplink signals from the UE and the at least one other UE or a measurement by the UE and the at least one other UE on downlink signals.

In an embodiment, the base station can determine a beam for the second message as described above. In an embodiment, the base station can determine a modulation coding scheme (MCS) for the second message as described above.

At block <NUM>, the base station transmits a second message as respective response to respective first message of the UE and at least one other UE. In this embodiment, the second message can multiplex respective response to respective first message of the UE and at least one other UE. The base station may determine a modulation coding scheme (MCS) for the second message as one of MCS corresponding to a lowest signal/link quality between the UE's signal/link quality and the at least one other UE's signal/link quality; MCS corresponding to a signal/link quality of a UE with a higher priority between the UE and the at least one other UE; and MCS with the lowest coding rate and/or the lowest modulation order selected from a group of MCSs determined for the UE and the at least one other UE.

In an embodiment, the base station can determine a beam for the second message as describe above. In an embodiment, the base station can determine a radio network temporary identifier (RNTI) for the second message as describe above.

In a first embodiment, there is provided a method for an initial access procedure in a user equipment of indicating the quality of a plurality of reference signals. The method comprise.

The method of first embodiment, wherein the candidates in the candidate set comprise synchronization signal blocks.

At block <NUM>, the base station receives a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) from a user equipment (UE). The RACH preamble or the RACH occasion indicates an SSB selected by the UE based on a mapping of the SSB to the RACH preamble and the RACH occasion. The selected SSB has a signal measured metric satisfying a criterion.

At block <NUM>, the base station transmits a second message as a response to the first message to the UE.

In an embodiment, the data comprises information indicating at least one SSB with the signal measured metric satisfying the criterion, the method further comprises: selecting a downlink beam for transmitting the second message to the UE based on the indication in the data.

<FIG> is a block diagram showing an apparatus suitable for use in practicing some embodiments of the disclosure. For example, any one of the UE and the base station described above may be implemented through the apparatus <NUM>.

The apparatus <NUM> comprises at least one processor <NUM>, such as a DP, and at least one MEM <NUM> coupled to the processor <NUM>. The apparatus <NUM> may further comprise a transmitter TX and receiver RX <NUM> coupled to the processor <NUM>. The MEM <NUM> stores a PROG <NUM>. The PROG <NUM> may include instructions that, when executed on the associated processor <NUM>, enable the apparatus <NUM> to operate in accordance with the embodiments of the present disclosure. A combination of the at least one processor <NUM> and the at least one MEM <NUM> may form processing means <NUM> adapted to implement various embodiments of the present disclosure.

Various embodiments of the present disclosure may be implemented by computer program executable by one or more of the processor <NUM>, software, firmware, hardware or in a combination thereof.

The MEM <NUM> may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memories and removable memories, as non-limiting examples.

The processor <NUM> may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors DSPs and processors based on multicore processor architecture, as non-limiting examples.

<FIG> is a block diagram showing a UE according to an embodiment of the disclosure. As shown, the UE <NUM> comprises a transmission module <NUM> and a reception module <NUM>. The transmission module <NUM> may be configured to transmit a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) to a base station, wherein the data includes information of at least one synchronization signal and physical broadcast channel block (SSB) with a signal measured metric satisfying a criterion, as described above with respect to block <NUM> of <FIG>. The reception module <NUM> may be configured to receive a second message as a response to the first message, as described above with respect to block <NUM> of <FIG>.

<FIG> is a block diagram showing a base station according to an embodiment of the disclosure. As shown, the base station <NUM> comprises a reception module <NUM> and a transmission module <NUM>. The reception module <NUM> may be configured to a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) from a user equipment (UE), wherein the data includes information of at least one synchronization signal and physical broadcast channel block (SSB) with a signal measured metric satisfying a criterion, as described above with respect to block <NUM> of <FIG>. The transmission module <NUM> may be configured to transmit a second message as a response to the first message, as described above with respect to <NUM> of <FIG>.

<FIG> is a block diagram showing a base station according to an embodiment of the disclosure. As shown, the base station <NUM> comprises a reception module <NUM> and a transmission module <NUM>. The reception module <NUM> may be configured to a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) from a user equipment (UE), as described above with respect to block <NUM> of <FIG>. The transmission module <NUM> may be configured to transmit a second message as respective response to respective first message of the UE and at least one other UE, as described above with respect to <NUM> of <FIG>. In an embodiment, the based station may determine a beam for the second message as one of a common downlink beam of the UE and the at least one other UE; a beam covering at least one of the UE's preferred beam and the at least one other UE's preferred beam; a preferred beam of a UE with a higher priority between the UE and the at least one other UE; and a beam randomly selected from the UE's preferred beam and the at least one other UE's preferred beam.

<FIG> is a block diagram showing a base station according to an embodiment of the disclosure. As shown, the base station <NUM> comprises a reception module <NUM> and a transmission module <NUM>. The reception module <NUM> may be configured to a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) from a user equipment (UE), as described above with respect to block <NUM> of <FIG>. The transmission module <NUM> may be configured to transmit a second message as respective response to respective first message of the UE and at least one other UE, as described above with respect to <NUM> of <FIG>. In an embodiment, the based station may determine a radio network temporary identifier (RNTI) for the second message as one of a common RNTI of the UE and the at least one other UE; a UE specific RNTI of a UE with a higher priority between the UE and the at least one other UE; a UE specific RNTI randomly selected from the UE's UE specific RNTI and the at least one other UE's UE specific RNTI; and a UE specific RNTI determined based on a measurement on uplink signals from the UE and the at least one other UE or a measurement by the UE and the at least one other UE on downlink signals.

<FIG> is a block diagram showing a base station according to an embodiment of the disclosure. As shown, the base station <NUM> comprises a reception module <NUM> and a transmission module <NUM>. The reception module <NUM> may be configured to a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) from a user equipment (UE), as described above with respect to block <NUM> of <FIG>. The transmission module <NUM> may be configured to transmit a second message as respective response to respective first message of the UE and at least one other UE, as described above with respect to <NUM> of <FIG>. In an embodiment, the based station may determine a modulation coding scheme (MCS) for the second message as one of MCS corresponding to a lowest signal/link quality between the UE's signal/link quality and the at least one other UE's signal/link quality; MCS corresponding to a signal/link quality of a UE with a higher priority between the UE and the at least one other UE; and MCS with the lowest coding rate and/or the lowest modulation order selected from a group of MCSs determined for the UE and the at least one other UE.

<FIG> is a block diagram showing a user equipment (UE) according to another embodiment of the present disclosure. The UE <NUM> comprises a selecting module <NUM>, a transmitting module <NUM> and a receiving module <NUM>. The selecting module <NUM> is configured to select a synchronization signal and physical broadcast channel block (SSB) with a signal measured metric satisfying a criterion. The transmitting module <NUM> is configured to transmit a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) to a base station. The RACH preamble and the RACH occasion are selected based on a mapping of the SSB to the RACH preamble and the RACH occasion. The receiving module <NUM> is configured to receive a second message from the base station as a response to the first message.

<FIG> is a block diagram showing a base station according to another embodiment of the present disclosure. The base station <NUM> comprises a receiving module <NUM> and a transmitting module <NUM>. The receiving module <NUM> is configured to receive a first message including a random access channel (RACH) preamble on a RACH occasion and data on an uplink shared channel (USCH) from a user equipment (UE). The RACH preamble or the RACH occasion indicates an SSB selected by the UE based on a mapping of the SSB to the RACH preamble and the RACH occasion. The selected SSB has a signal measured metric satisfying a criterion. The a transmitting module <NUM> is configured to transmit a second message as a response to the first message to the UE.

Access network <NUM> comprises a plurality of base stations 3212a, 3212b, 3212c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 3213a, 3213b, 3213c. Each base station 3212a, 3212b, 3212c is connectable to core network <NUM> over a wired or wireless connection <NUM>. A first UE <NUM> located in coverage area 3213c is configured to wirelessly connect to, or be paged by, the corresponding base station 3212c. A second UE <NUM> in coverage area 3213a is wirelessly connectable to the corresponding base station 3212a.

It is noted that host computer <NUM>, base station <NUM> and UE <NUM> illustrated in <FIG> may be similar or identical to host computer <NUM>, one of base stations 3212a, 3212b, 3212c and one of UEs <NUM>, <NUM> of <FIG>, respectively.

Wireless connection <NUM> between UE <NUM> and base station <NUM> is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to UE <NUM> using OTT connection <NUM>, in which wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may improve the latency and thereby provide benefits such as reduced user waiting time.

According to an aspect of the disclosure it is provided a computer program product being tangibly stored on a computer readable storage medium and including instructions which, when executed on at least one processor, cause the at least one processor to carry out any of the methods as described above.

According to an aspect of the disclosure it is provided a computer-readable storage medium storing instructions which when executed by at least one processor, cause the at least one processor to carry out any of the methods as described above.

Many advantages may be achieved by applying the proposed solution according to embodiments of the present disclosure. For example, some embodiments provide a new method for indication of SSB by the UE. Some embodiments provide a new method for determine the beam to be used for the combined msgB transmission. Some embodiments provide a new method for determine the RNTI to be used for the combined msgB transmission/monitoring. Some embodiments provide a new method for determine the MCS to be used for the combined msgB transmission.

The techniques described herein may be implemented by various means so that an apparatus implementing one or more functions of a corresponding apparatus described with an embodiment comprises not only prior art means, but also means for implementing the one or more functions of the corresponding apparatus described with the embodiment and it may comprise separate means for each separate function or means that may be configured to perform two or more functions. For example, these techniques may be implemented in hardware (one or more apparatuses), firmware (one or more apparatuses), software (one or more modules), or combinations thereof. For a firmware or software, implementation may be made through modules (e.g., procedures, functions, and so on) that perform the functions described herein.

Claim 1:
A method (<NUM>) at a user equipment, UE, comprising:
selecting (<NUM>) a synchronization signal and physical broadcast channel block, SSB, with a signal measured metric satisfying a criterion;
transmitting (<NUM>) a first message including a random access channel, RACH, preamble on a RACH occasion and data on an uplink shared channel, USCH, to a base station, wherein the RACH preamble and the RACH occasion are selected based on a mapping of the SSB to the RACH preamble and the RACH occasion; and
receiving (<NUM>) a second message from the base station as a response to the first message,
wherein the second message multiplexes respective response to respective first message of the UE and at least one other UE,
wherein a radio network temporary identifier, RNTI, for the second message is one of a common RNTI of the UE and the at least one other UE;
a UE-specific RNTI with a higher priority between the UE and the at least one other UE;
a UE-specific RNTI randomly selected from the UE's UE specific RNTI and the at least one other UE's UE specific RNTI; and
a UE-specific RNTI determined based on a measurement on uplink signals from the UE and the at least one other UE or a measurement by the UE and the at least one other UE on downlink signals.