Patent Description:
To expand the utilization and coverage of radio access technologies such as but not limited to Long-Term-Evolution (LTE) technologies and New Radio (NR) technologies, connectivity provided by satellites and airborne vehicles has been considered as a promising application. A network incorporating satellites and/or airborne vehicles to perform the functions (either full or partial) of terrestrial Base Stations (BSs) is called a Non-Terrestrial Network (NTN). Satellites and airborne vehicles are collectively referred to as non-terrestrial BSs. Examples of satellites include but are not limited to, Low Earth Orbit (LEO) satellites, and so on. Examples of airborne vehicles include but are not limited to, High-Altitude Platform Stations (HAPS), balloons, Unmanned Aerial Vehicles (UAVs), other suitable airborne vehicles, and so on.

<CIT>, <CIT> and <CIT> are related prior art documents.

The invention is specified and limited by the independent claims. The example embodiments disclosed herein are directed to solving the issues relating to one or more of the problems presented in the prior art, as well as providing additional features that will become readily apparent by reference to the following detailed description when taken in conjunction with the accompany drawings. In accordance with various embodiments, example systems, methods, devices and computer program products are disclosed herein.

In NTNs, the coverage of a satellite or an airborne vehicle is generally implemented using multiple beams. For example, the beams of a satellite can sweep across a coverage area as the satellite moves along its orbit. A User Equipment (UE) that is fixed or relatively fixed on the ground is served by different beams of the satellite over time, as the satellite moves. The coverage area of a satellite can be large, e.g., with a single satellite beam footprint diameter of hundreds of kilometers. The number of UEs within the satellite's coverage is likewise expected to be large. Therefore, the large number of UEs have to change serving beams with the movement of the satellite. This is also true for airborne vehicles, which can move while providing network coverage.

Considering signaling cost saving, beam switching is more preferable over cell switching. On one hand, a UE identifies and measures its serving beam and neighboring beams to facilitate beam switching. One the other hand, cell-level synchronization/broadcast signals of multiple beams generally occupy a same frequency resource to ease downlink synchronization at the UE side. The cell-level synchronization/broadcast signals of different beams can be multiplexed in time domain, for example, via multiple Synchronization Signal Blocks (SSBs) in the time domain for beam measurement, where each SSB corresponds to one of the beams. Such time-domain beam-level multiplexing needs longer synchronization period at the UE side and thus higher power consumption.

For a cell with multiple beams, cell-level synchronization/broadcast signals of the multiple beams generally occupy a same frequency resource to ease downlink synchronization at the UE side. In conventional NR deployment, the cell-level Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and PBCH of different beams can be multiplexed in time domain. Such design is not well-suited for the NTN because different beams of a non-terrestrial BS in NTN generally cover different areas, have large coverage areas, and have less overlap. Accordingly, arrangements disclosed herein are directed to simultaneous PSS, SSS, and PBCH transmissions in multiple beams to achieve time-efficient and energy efficient synchronization.

The concept of beams has not be implemented for conventional Narrow Band (NB) Internet-of-Things (IoT). In NB IoT, cell-level PSS, SSS, and PBCH are transmitted on an anchor carrier only. A UE cannot determine or otherwise identify the beam on which the UE resides from the received PSS, SSS, and/or PBCH. Thus, the UE cannot perform neighboring carrier measurement. Such design is also not well-suited for the NTN scenario because beam-level frequency pre-compensation at BS cannot be performed at all.

In some examples, PBCH is transmitted with a period (e.g., having a length of <NUM>). Each period includes a number (e.g., <NUM>) of sub-periods. In the example in which the period is <NUM> long and has <NUM> sub-periods, each sub-period has a length of <NUM>. In each sub-period, an identical PBCH (e.g., having a length of <NUM>) is transmitted in subframe #<NUM> of each frame.

The arrangements disclosed herein relate to systems, methods, and non-transitory computer-readable media for energy-efficient and time-efficient beam indication. In some implementations, the beam indication methods include using an Orthogonal Code Cover (OCC) in Physical Broadcast Channel (PBCH) repetition, which provides beam indication. In some implementations, the beam indication methods include applying scrambling sequences corresponding to each beam in PBCH repetition to provide beam indication.

In some embodiments, a beam can be regarded as a physical resource. Abeam can be represented or defined by one or more of <NUM>) a reference signal ID, <NUM>) reference signal association (e.g., Quasi-Co-Located (QCL), <NUM>) a polarization pattern, <NUM>) a physical resource ID such as but not limited to, a resource including a frequency resource, e.g., a Bandwidth Part (BWP), carrier(s), and so on; a spatial resource, including but not limited to, an antenna port (e.g., sharing a same port or within an antenna port group); a Code Division Multiplex (CDM) group, e.g., CDM Demodulation Reference Signal (DM-RS), or <NUM>) a logic ID, which can be defined by the association between some implementation based arrangement, e.g., area ID/tracking area ID, which is based on the location.

<FIG> is diagram illustrating beams of a cell <NUM> of a BS in a wireless communication system, according to various arrangements. Referring to <FIG>, the BS can be a non-terrestrial BS such as but not limited to, a satellite or an airborne vehicle. The BS shown in the example in <FIG> provides multiple beams, including beams <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. Each of the beams <NUM>-<NUM> forms a coverage area. The UE can transmit data to and receive data from the BS via one of the beams <NUM>-<NUM> while the UE is within the coverage area of that beam. The beams <NUM>-<NUM> (and the coverage areas thereof) collectively form the cell <NUM>.

In some examples, frequency reuse can be implemented to improve energy efficiency of the beams <NUM>-<NUM>. In frequency reuse, two or more different beams can transmit and/or receive data using a same frequency resource or a same frequency band. For example, the beam <NUM> can use a first frequency resource or a first frequency band. The beams <NUM> and <NUM> can use a second frequency resource or a second frequency band. The beams <NUM> and <NUM> can use a third frequency resource or a third frequency band. The beams <NUM> and <NUM> can use a fourth frequency resource or a fourth frequency band. The first, second, third, and fourth frequency resources are different frequency resources. The first, second, third, and fourth frequency bands are different frequency bands. A fixed or relatively fixed UE can be served by different beams (with different frequency resources) of the same non-terrestrial BS over time, as the non-terrestrial BS moves. To save signaling cost in mobility management, a non-terrestrial BS (e.g., a cell) with multiple beams is preferred.

<FIG> is a diagram illustrating frequency resources used by the beams <NUM>-<NUM> of the cell <NUM> (<FIG>), according to various arrangements. Referring to <FIG>, the frequency resources used by the beams <NUM>-<NUM> are shown on a diagram in which the y-axis corresponds to frequency and the x-axis corresponds to time. The frequency resources include frequency resources <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. Each of the frequency resources <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> corresponds to a frequency bandwidth or a Bandwidth Part (BWP). The non-terrestrial BS transmits PBCHs of all of the beams <NUM>-<NUM> using a common frequency resource, e.g., the frequency resource <NUM>. The beam <NUM> uses (is transmitted) the frequency resource <NUM>. The beams <NUM> and <NUM> use (are transmitted on) the frequency resource <NUM>. The beams <NUM> and <NUM> use (are transmitted on) the frequency resource <NUM>. The beams <NUM> and <NUM> use (are transmitted on) the frequency resource <NUM>.

In a NTN, PSS, SSS, and PBCH repetition can reduce large path loss. To facilitate beam identification, the arrangements disclosed herein can employ OCC in performing PBCH repetition. In particular, PBCH repetition is performed with beam-specific OCCs. PBCH is a broadcast channel through which a BS (e.g., a non-terrestrial BS) broadcasts information (e.g., configurations and parameters) for a control channel and a share channel corresponding thereto.

In some examples, the non-terrestrial BS transmits PBCH with a period having a length (e.g., <NUM>). Each period includes a number of sub-periods. In the example in which the period is <NUM> long and has <NUM> sub-periods, each sub-period has a length of <NUM>. In each sub-period, an identical PBCH (e.g., having a length of <NUM>) is transmitted in a particular subframe (e.g., subframe #<NUM>) of each radio frame. In some examples, an OCC code with a length no more than the number of consecutive identical PBCH subframes can be applied to distinguish beams.

In some arrangements, given that all beams (e.g., the beams <NUM>-<NUM>) share the same cell-level PBCH and the same frequency resource (e.g., the frequency resources <NUM>), a resource-specific (e.g., a beam-specific) OCC can be added to a series of <NUM>-ms PBCH to distinguish beams. An example of the OCC can be a Hadamard code. <FIG> is a table illustrating a Hadamard code for each of the beams <NUM>-<NUM> (<FIG>), according to various arrangements. Referring to <FIG>, the Hadamard code has a length of <NUM> and is used to distinguish the <NUM> beams <NUM>-<NUM>. As shown, a beam (e.g., the beam <NUM>) having a beam index <NUM> corresponds to the beam-specific OCC [<NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM>], a beam (e.g., the beam <NUM>) having a beam index <NUM> corresponds to the beam-specific OCC [<NUM> -<NUM><NUM> -<NUM><NUM> -<NUM><NUM> -<NUM>],. , a beam (e.g., the beam <NUM>) having a beam index <NUM> corresponds to the beam-specific OCC [<NUM><NUM> -<NUM> -<NUM> -<NUM> -<NUM><NUM><NUM>]. While the Hadamard code is shown as an example of the OCC code, other orthogonal codes (e.g., a Zadoff-Chu (ZC) sequence set, and so on) can be likewise implemented.

Each element of a beam-specific OCC is multiplied to a <NUM>-ms PBCH subframe. In a NTN, Line-of-Sight (LOS) probability is generally high due the NTN is deployed in an outdoor environment. Thus, the channel or communication link between a non-terrestrial BS and a UE is expected to be stable over time, if the Doppler pre-compensation or post-compensation is taken into account. In other words, the channel can be assumed to be stable.

The UE, in response to receiving the consecutive identical <NUM>-ms PBCHs (each in a subframe of a frame of a sub-period), combines the consecutive identical <NUM>-ms PBCHs with all possible beam-specific OCCs. For example, the UE can combine the <NUM> consecutive identical <NUM>-ms PBCH subframes with each beam-specific OCC corresponding to beam indexes <NUM>-<NUM> shown in <FIG> through multiplication. In one example, a first-received PBCH (of the <NUM> identical PBCHs, in the earlier sub-period) is multiplied with a first element of a beam-specific OCC (e.g., <NUM> for beam-specific OCC corresponding to beam index <NUM>), a second-received PBCH (of the <NUM> identical PBCHs, in the second earliest sub-period) is multiplied with a second element of the beam-specific OCC (e.g., -<NUM> for beam-specific OCC corresponding to beam index <NUM>),. , and a last-received PBCH (of the <NUM> identical PBCHs in the last sub-period) is multiplied with a last element of the beam-specific OCC (e.g., -<NUM> for beam-specific OCC corresponding to beam index <NUM>). The repetitions of the PBCH are likewise multiplied with the elements of the OCCs corresponding to each of beam indexes <NUM> and <NUM>-<NUM>.

The resultant measurement corresponding to each beam-specific OCC (e.g., the resulting RSRP of each beam as measured, if higher than a detectable threshold), is used by the UE to determine a serving beam and one or more neighboring beams. The resultant measurement can be reported to the non-terrestrial BS to facilitate possible beam switching. In some examples, the number of neighboring beams to be reported can be indicated by the non-terrestrial BS via UE-specific signaling, UE group signaling, or broadcast. The UE can report the measurements of the number of neighboring beams to the non-terrestrial BS.

In some arrangements, a length of the beam-specific OCC (referred to as N) can be determined according to a number of neighboring beams to be measured. In the example shown in <FIG> in which <NUM> total beams and <NUM> neighboring beams are deployed, N needs to be sufficiently large (e.g., <NUM>, which is <NUM><NUM>) for distinguishing the different beams without creating waste (e.g., <NUM>, which is <NUM><NUM> would be too large to cover <NUM> neighboring beams). The number of neighboring beams to be measured can be set according to practical deployment configurations. In other words, the number of neighboring beams to be measured can be predefined. The non-terrestrial BS can indicate or information the value of N to the UEs via PBCH. Given that the OCC combination over the consecutive identical PBCH subframes depends on successful decoding of the PBCH subframes, the value of N can be available after successful decoding of a single PBCH subframe. The OCC codes or the generation method thereof can be predefined and known by the non-terrestrial BS and UEs in advance. Accordingly, in response to determining the length (N) of the beam-specific OCC by decoding a single PBCH subframe, the UE can generate the OCC codes having the length N according to any suitable predetermined or predefined method (corresponding to a given type of the OCC codes such as the Hadamard code, ZC sequence set, and so on).

In some arrangements, the OCC code is a ZC sequence set. An example ZC sequence set can be a length-<NUM> ZC root sequence xu, which can be generated using expression (<NUM>): <MAT> where n = <NUM>. NZC - <NUM>, NZC = <NUM>. NZC is the length of the ZC sequence set, which is <NUM> in this case. The ZC root u can be cell-specific. For example, the ZC root u can be determined using expression (<NUM>): <MAT> where <MAT> is a cell identifier. Each beam of the same cell has a beam-specific cyclic shift CbeamID. For example, the beam-specific cyclic shift CbeamID can be determined using expression (<NUM>): <MAT>.

Accordingly, an example of the beam-specific OCC code can be the ZC root sequence shown in expression (<NUM>): <MAT>.

In some examples, only part of the <NUM>-ms PBCH in a <NUM>-ms sub-period has the OCC applied. <FIG> is a diagram illustrating an application of an OCC (e.g., a length-<NUM> OCC <NUM>) in a sub-period <NUM>, according to various arrangements. Referring to <FIG>, an example of the length-<NUM> OCC <NUM> is a length-<NUM> ZC root sequence. The sub-period <NUM> includes <NUM> frames (frames <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>) of <NUM> each. Each frame includes <NUM> subframes of <NUM>. In the sub-period <NUM>, an identical PBCH (e.g., having a length of <NUM>) is transmitted in subframe #<NUM> of each of the frame <NUM>-<NUM>. As shown, the length-<NUM> OCC <NUM> is applied to the identical PBCH repetitions in frames <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, but not the frame <NUM>.

In some satellite communication systems, the beam deployment may be different from conventional terrestrial networks. <FIG> is a diagram illustrating an example satellite communication beam deployment, according to various arrangements. Referring to <FIG>, a satellite <NUM> can provide band-shaped beams <NUM>, <NUM>, <NUM>, and <NUM>. Each of the beams <NUM>-<NUM> forms a coverage area. UEs can transmit data to and receive data from the satellite <NUM> via one of the beams <NUM>-<NUM> while the UE is within the coverage area of that beam. The beams <NUM>-<NUM> (and the coverage areas thereof) collectively form a cell <NUM>.

In some examples, frequency reuse can be implemented to improve energy efficiency of the beams <NUM>-<NUM>. In frequency reuse, two or more different beams can transmit and/or receive data using a same frequency resource or a same frequency band. For example, the beams <NUM> and <NUM> can use one frequency resource or frequency band. The beams <NUM> and <NUM> can use another frequency resource or frequency band.

<FIG> is a diagram illustrating frequency resources used by the beams <NUM>-<NUM> of the satellite <NUM> (<FIG>), according to various arrangements. Referring to <FIG> and <FIG>, the frequency resources used by the beams <NUM>-<NUM> are shown on a diagram in which the y-axis corresponds to frequency and the x-axis corresponds to time. The frequency resources include frequency resources <NUM>, <NUM>, and <NUM>. Each of the frequency resources <NUM>, <NUM>, and <NUM> corresponds to a frequency bandwidth or a BWP. The satellite <NUM> transmits PBCHs of all of the beams <NUM>-<NUM> using a common frequency resource, e.g., the frequency resource <NUM>. The beams <NUM> and <NUM> use (are transmitted on) the frequency resource <NUM>. The beams <NUM> and <NUM> use (are transmitted on) the frequency resource <NUM>.

In the deployment shown in <FIG> and <FIG>, an OOC code with a length of <NUM> can be used to distinguish the beams <NUM>-<NUM>. Given that the cell has the <NUM> beams <NUM>-<NUM>, a length-<NUM> OCC is used in view of energy leak. A beam-specific length-<NUM> OCC corresponds to each of the beams <NUM>-<NUM>. <NUM> consecutive identical <NUM>-ms PBCH subframes are received by the UE from the satellite <NUM>.

In some examples, the OCC code can be determined using a Discrete Fourier Transform (DFT) matrix. An example of such DFT matrix is shown below: <MAT>.

The UE, in response to receiving the consecutive identical <NUM>-ms PBCHs (each in a subframe of a sub-period), combines the consecutive identical <NUM>-ms PBCHs with all possible beam-specific OCCs (<NUM> beam-specific OCCs determined using the DFT matrix in the deployment shown in <FIG> and <FIG>). For example, the UE can combine the <NUM> consecutive identical <NUM>-ms PBCH subframes with each beam-specific OCC corresponding to a different beam index through multiplication. In one example, a first-received PBCH (of the <NUM> identical PBCHs, in the earlier sub-period) is multiplied with a first element of a length-<NUM> beam-specific OCC, a second-received PBCH (of the <NUM> identical PBCHs, in the second earliest sub-period) is multiplied with a second element of the length-<NUM> beam-specific OCC, a third-received PBCH (of the <NUM> identical PBCHs, in the third earliest sub-period) is multiplied with a third element of the length-<NUM> beam-specific OCC, and a fourth-received PBCH (of the <NUM> identical PBCHs, in the fourth earliest sub-period) is multiplied with a last element of the length-<NUM> beam-specific OCC.

The resultant measurement corresponding to each beam-specific OCC (e.g., the resulting RSRP of each beam as measured, if higher than a detectable threshold), is used by the UE to determine a serving beam and one or more neighboring beams. The resultant measurement can be reported to the satellite <NUM> to facilitate possible beam switching. In some examples, the number of neighboring beams to be reported can be indicated by the satellite <NUM> via UE-specific signaling, UE group signaling, or broadcast. The UE can report the measurements of the number of neighboring beams to the satellite <NUM>.

In some arrangements, a length N of the beam-specific OCC can be determined according to a number of neighboring beams to be measured. In the example shown in <FIG> in which <NUM> total beams and <NUM> neighboring beams are deployed, N needs to be sufficiently large (e.g., <NUM>, which is <NUM><NUM>) for distinguishing the different beams without creating waste (e.g., <NUM>, which is <NUM><NUM> would be too large to cover <NUM> neighboring beams). The number of neighboring beams to be measured can be set according to practical deployment configurations. In other words, the number of neighboring beams to be measured can be predefined. The satellite <NUM> can indicate or information the value of N to the UEs via PBCH. Given that the OCC combination over the consecutive identical PBCH subframes depends on successful decoding of the PBCH subframes, the value of N can be available after successful decoding of a single PBCH subframe. The OCC codes or the generation method thereof can be predefined and known by the non-terrestrial BS and UEs in advance. Accordingly, in response to determining the length N of the beam-specific OCC by decoding a single PBCH subframe, the UE can generate the OCC codes having the length N according to any suitable predetermined or predefined method (e.g., based on the DFT matrix).

In some examples, each element of a beam specific OCC is multiplied to a corresponding <NUM>-ms PBCH subframe as shown in <FIG> is a diagram illustrating an application of an OCC (e.g., a length-<NUM> OCC <NUM>) in a sub-period <NUM>, according to various arrangements. Referring to <FIG>, an example of the length-<NUM> OCC <NUM> is a length-<NUM> OCC code obtained using the DFT matrix. The sub-period <NUM> includes <NUM> frames (frames <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>) of <NUM> each. Each frame includes <NUM> subframes of <NUM>. In the sub-period <NUM>, an identical PBCH (e.g., having a length of <NUM>) is transmitted in subframe #<NUM> of each of the frame <NUM>-<NUM>. As shown, the length-<NUM> OCC <NUM> is applied to the identical PBCH repetitions the frames <NUM>-<NUM>, and the length-<NUM> OCC <NUM> is applied again to the identical PBCH repetitions the frames <NUM>-<NUM>.

<FIG> is a flowchart diagram illustrating an example wireless communication method 800a for indicating beam-specific broadcast information, according to various arrangements. Referring to <FIG>, the method 800a can be performed by a BS (e.g., a non-terrestrial BS). The method 800a is concerned with using OCC codes in PBCH repetition, which provides beam indication.

At 810a, the BS applies code sequences (e.g., OCC codes) to repetitions of broadcast information of a plurality of resources of a cell of the BS. Each of the OCC codes is specific to a corresponding one of the plurality of resources, thus the OCC codes are beam-specific codes. Each of the resources is a beam as described herein. While the OCC codes are used throughout as an example of code sequences, other types of code sequences such as but not limited to, low correlated codes, can be implemented such that each code sequence is beam-specific. In some embodiments, the code sequences comprise at least one of the OCC codes or a low correlated codes.

In some examples, the repetitions of the broadcast information for each resource of the plurality of resources include a number of repetitions of PBCH (e.g., in a repetition period). The PBCH is identical in each repetition of the number of repetitions. In some examples, each of the OCC codes has a length that is no more than the number of repetitions of the PBCH. That is, an OCC code with a length no more than the number of consecutive identical PBCH subframes can be applied to distinguish beams.

In some examples, the BS applies the OCC codes to the repetitions of the broadcast information includes combining the repetitions of the PBCH for each resource of the plurality of resources with a corresponding one of the OCC codes that is specific to each resource.

In some examples, combining the repetitions of the PBCH for each resource of the plurality of resources with the corresponding one of the OCC codes includes multiplying each repetition of the repetitions of the PBCH for each resource with a corresponding element of the corresponding one of the OCC codes in response to determining that a length of the OCC codes equals to the repetition number of PBCH.

In some examples, combining the repetitions of the PBCH for each resource of the plurality of resources with the corresponding one of the OCC codes includes applying the OCC codes to a predetermined portion of the repetitions of the PBCH in response to determining that the length of the OCC codes is less than the repetition number of PBCH, wherein the portion of the repetitions of the PBCH is predetermined. For example, relative to <FIG> in which <NUM> OCC codes (e.g., the length-<NUM> OCC <NUM>) are used to distinguish <NUM> beam, the BS applies the OCC codes to only a portion (e.g., the repetitions in the frames <NUM>-<NUM>) of the repetitions of PBCH. A portion refers to some but not all of the repetitions. In some examples, the portion is predetermined and known by both the BS and UE in advance. Thus, the BS can apply the OCC code to the known portions (e.g., the known frames and subframes) of the sub-period <NUM> during transmission, and the UE can use the OCC in those known portions upon reception.

In some arrangements, the OCC codes are generated from a Hadamard matrix. In some arrangements, the OCC codes corresponds to a ZC sequence set. The ZC sequence set includes resource-specific ZC sequence corresponding to the plurality of resources. The ZC sequence set is determined using a cell-specific ZC root and a resource-specific cyclic shift. In some arrangements, the OCC codes are generated from a DFT matrix.

At 820a, the BS transmits to a UE the repetitions of the broadcast information with the OCC codes applied.

In some arrangements, the BS transmits to the UE a parameter corresponding to a number of neighboring resources Nneighboring_resources (or a number of neighboring beams Nneighboring_beams) of the cell to be measured. The BS receives from the UE measurements for the number of neighboring resources. The measurements are performed by the UE using the resource-specific OCC codes.

In some arrangements, the BS transmits to the UE a length of the OCC codes. The UE determines a maximum value of the number of neighboring resources Nneighboring_resources based on the length of the OCC codes. In the example in which the BS transmits to the UE a length of <NUM> for the OCC codes, <NUM> of those OCC codes is for the serving beam and <NUM> for the neighboring beams. Thus, the number of neighboring resources Nneighboring_resources is implicitly indicated, without the BS actually indicating the parameter Nneighboring_resources that explicitly indicates the number of neighboring resources, thus saving signaling overhead and improving efficiency. In other words, the maximum value of the number of neighboring beams to be measured and reported can be determined from the length of the OCC obtained from the BS.

<FIG> is a flowchart diagram illustrating an example wireless communication method 800b for indicating beam-specific broadcast information, according to various arrangements. Referring to <FIG>, the method 800b can be performed by a UE and corresponds to the operations performed by the BS in the method 800a. The method 800b is concerned with using OCC codes in PBCH repetition, which provides beam indication.

At 810b, the UE receives from the BS repetitions of broadcast information of a plurality of resources of a cell of the BS with code sequences (e.g., OCC codes) applied. Each of the OCC codes is specific to a corresponding one of the plurality of resources. While the OCC codes are used throughout as an example of code sequences, other types of code sequences such as but not limited to, low correlated codes, can be implemented such that each code sequence is beam-specific. In some embodiments, the code sequences comprise at least one of the OCC codes or a low correlated codes.

At 820b, the UE determines measurements for each of the plurality of resources distinguished using the OCC codes.

In some examples, the method 800b further includes the UE receiving, from the BS, a parameter corresponding to a number of neighboring resources Nneighboring_resources of the cell to be measured. The UE determining the measurements for each of the neighboring resources distinguished using the OCC codes includes determining measurements for the number of neighboring resources using the resource-specific OCC codes. The UE reports to the BS the measurements for the number of the neighboring resources.

In some examples, the method 800b further includes determining, by the UE, a maximum value of a number of the neighboring resources Nneighboring_resources of the cell based on a length of the OCC codes received from the BS. In the example in which the UE receives from the BS a length of <NUM> for the OCC codes, <NUM> of those OCC codes is for the serving beam and <NUM> for the neighboring beams. Thus, the number of neighboring resources Nneighboring_resources is implicitly indicated, without the BS actually indicating the parameter Nneighboring_resources that explicitly indicates the number of neighboring resources, thus saving signaling overhead and improving efficiency. In other words, the maximum value of the number of neighboring beams to be measured and reported can be determined from the length of the OCC obtained from the BS.

In some arrangements, beam-specific scrambling can be implemented with PBCH repetition.

In some examples, the non-terrestrial BS transmits PBCH with a period having a length (e.g., <NUM>). Each period includes a number of sub-periods. In the example in which the period is <NUM> long and has <NUM> sub-periods, each sub-period has a length of <NUM>. In each sub-period, an identical PBCH (e.g., having a length of <NUM>) is transmitted in a particular subframe (e.g., subframe #<NUM>) of each radio frame. A Master Information Block (MIB) is coded into a number of bits (e.g.,<NUM> bits) and divided into a number of portions (e.g., <NUM> parts, where each part is <NUM> bits). The scrambling code applied on each <NUM>-bit part is different from the scrambling code applied to another one of the <NUM>-bit parts. Each <NUM>-ms PBCH contains a <NUM>-bit part of the MIB. In a sub-period of <NUM>, the same <NUM>-bit part of the MIB is transmitted in <NUM> consecutive subframe #<NUM> of each radio frame. The <NUM>-ms boundary is determined by the UE using a scrambling code test.

In some arrangements, in conventional NB IoT specifications, the <NUM>-bit scrambling sequence can be initialized using a scrambling code initialization value cinit is initialized using: <MAT> where <MAT> is a cell identifier identifying the cell/BS. Radio frames for which cinit is initialized include those radio frames nf that satisfy: <MAT>.

Modifying the conventional determination, and taking the cell <NUM> with the <NUM> beams <NUM>-<NUM> as shown in <FIG> for example, a scrambling code initialization value cinit can be designed to integrate a beam ID, and can be determined using the example expression: <MAT> where M is a beam interval value, <MAT> is a cell identifier, and <MAT> is a beam identifier. <MAT> identifies multiple beams (e.g., the beams <NUM>-<NUM>) of the cell <NUM> (identified by <MAT>). In some examples, M can be predefined. In some example, M is predefined to be <NUM> for the <NUM> beams <NUM>-<NUM>. The value M can be specified and known by the BS and the UEs in advance.

Using expression (<NUM>), examples of cell-and-beam-specific scrambling code initialization values are shown below, to be applied in radio frames that satisfy expression (<NUM>): <MAT>.

Given that conventionally, <NUM> total cell-specific scrambling code initialization values cinit had been defined, the cell-and-beam-specific scrambling code initialization values start from <NUM> to avoid overlap.

At the UE side, the UE obtains the cell ID <MAT> after successfully detecting PSS/SSS. Then, the UE can use M possible scrambling codes, each determined based on one of the cell-and-beam-specific scrambling code initialization values corresponding to the cell ID (e.g., as shown above) to determine the serving beam. In other words, the UE blind checks each cell-and-beam-specific scrambling code (e.g., for cell ID being <NUM>, each cell-and-beam-specific scrambling code determined using one of the cell-and-beam-specific scrambling code initialization values <NUM>-<NUM>) to determine the serving beam. The measurement of neighboring beams can be obtained by a Successive Interference Cancellation (SIC) receiver.

In some arrangements, to reduce the UE blind de-scrambling time , the cell-and-beam-specific scrambling code initialization values can be applied to only a portion of the <NUM>-ms PBCH in a <NUM> sub-period. An example is illustrated in <FIG>, which is a diagram illustrating an application of cell-and-beam-specific scrambling code initialization values in a sub-period <NUM>, according to various arrangements. Referring to <FIG>, the sub-period <NUM> includes <NUM> frames (frames <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>) of <NUM> each. Each frame includes <NUM> subframes of <NUM>. Each of the frames <NUM>-<NUM> includes a PBCH transmission. A cell-and-beam-specific scrambling code initialization value is applied only in the last <NUM>-ms PBCH transmission (in the frame <NUM>) of the <NUM>-ms sub-period <NUM>. For each of the first <NUM><NUM>-ms PBCH transmissions each in a respective one of the frames <NUM>-<NUM>, a cell-specific scrambling code initialization value is used. Given that the first <NUM><NUM>-ms PBCH can be decoded and blind de-scrambling only needs to be performed with the last frame <NUM>, blind de-scrambling time can be significantly reduced.

Thus, the UE can successfully detect PBCH with cell-specific scrambling code with a large probability, and obtain the value M in expression (<NUM>) in MIB. Then the UE shall use the M possible scrambling codes corresponding to the initial values to determine the serving beam. The measurement of neighboring beams can be obtained by the SIC receiver.

<FIG> is a flowchart diagram illustrating an example wireless communication method 1000a for indicating beam-specific broadcast information, according to various arrangements. Referring to FIGS. <NUM>, <FIG>, <FIG>, <FIG>, and <FIG>, the method 1000a can be performed by a BS. The method 1000a is concerned with using beam-specific scrambling in PBCH repetition, which provides beam indication.

At 1010a, the BS applies scrambling sequences to broadcast information of a plurality of resources of a cell of the BS. Each of the scrambling sequences is specific to a resource of the plurality of resources.

In some examples, the broadcast information for each resource of the plurality of resources include a number of repetitions of PBCH (e.g., in a repetition period). The PBCH is identical in each repetition of the number of repetitions. Each of the resources is a beam as described herein.

In some arrangements, the method 1000a further includes determining each of the scrambling sequences using a scrambling code initialization value specific to the resource. The scrambling code initialization value is determined based on at least a resource ID and a cell ID. The cell ID identifies the BS. The resource ID identifies one of the plurality of resources.

In some arrangements, applying the resource-specific scrambling sequences to the broadcast information includes applying the resource-specific scrambling sequences to at least one first repetition of the repetitions of the PBCH. The at least one first repetition is predetermined and known by both the UE and the BS in advance. The other repetitions (e.g., second repetitions) can apply conventional cell-specific scrambling codes.

In some examples, the BS applies resource-specific scrambling sequences to a predetermined portion of the repetitions of the PBCH. The predetermined portion of the repetitions of the PBCH includes at least one repetition of the repetitions of the PBCH.

In some examples, the BS transmitting an Information Element (IE) indicative of a scrambling code initialization value interval parameter (e.g., the beam interval parameter M) used to determine a scrambling code initialization value specific to each resource of the plurality of resources.

At 1020a, the BS transmits to the UE the broadcast information with the scrambling sequences applied.

<FIG> is a flowchart diagram illustrating an example wireless communication method 1000b for indicating beam-specific broadcast information, according to various arrangements. Referring to FIGS. <NUM>, <FIG>, <FIG>, <FIG>, <FIG>, the method 1000b can be performed by a UE and corresponds to the operations performed by the BS in the method 1000a. The method 1000b is concerned with using beam-specific scrambling in PBCH repetition, which provides beam indication.

At 1010b, the UE determines scrambling sequences. Each of the scrambling sequences is specific to a resource of a plurality of resources of a cell of a BS. At 1020b, the UE determines a serving resource using the scrambling sequences.

In some examples, determining the serving resource using the scrambling sequences includes applying beam-specific scrambling sequences to a predetermined portion of repetitions of PBCH. The predetermined portion of the repetitions of the PBCH includes at least one repetition of the repetitions of the PBCH.

In some examples, the method 1000b further includes receiving an IE indicative of a scrambling code initialization value interval parameter (e.g., the beam interval parameter M) used to determine a scrambling code initialization value specific to each resource of the plurality of resources.

<FIG> illustrates a block diagram of an example BS <NUM> (e.g., a non-terrestrial BS described herein), in accordance with some embodiments of the present disclosure. <FIG> illustrates a block diagram of an example UE <NUM>, in accordance with some embodiments of the present disclosure. Referring to <FIG>, the UE <NUM> (e.g., a wireless communication device, a terminal, a mobile device, a mobile user, and so on) is an example implementation of the UEs described herein, and the BS <NUM> is an example implementation of the BS described herein.

The BS <NUM> and the UE <NUM> can include components and elements configured to support known or conventional operating features that need not be described in detail herein. In one illustrative embodiment, the BS <NUM> and the UE <NUM> can be used to communicate (e.g., transmit and receive) data symbols in a wireless communication environment, as described above. For instance, the BS <NUM> can be a BS (e.g., gNB, eNB, and so on), a server, a node, or any suitable computing device used to implement various network functions.

The BS <NUM> includes a transceiver module <NUM>, an antenna <NUM>, a processor module <NUM>, a memory module <NUM>, and a network communication module <NUM>. The module <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are operatively coupled to and interconnected with one another via a data communication bus <NUM>. The UE <NUM> includes a UE transceiver module <NUM>, a UE antenna <NUM>, a UE memory module <NUM>, and a UE processor module <NUM>. The modules <NUM>, <NUM>, <NUM>, and <NUM> are operatively coupled to and interconnected with one another via a data communication bus <NUM>. The BS <NUM> communicates with the UE <NUM> or another BS via a communication channel, which can be any wireless channel or other medium suitable for transmission of data as described herein.

As would be understood by persons of ordinary skill in the art, the BS <NUM> and the UE <NUM> can further include any number of modules other than the modules shown in <FIG>. The various illustrative blocks, modules, circuits, and processing logic described in connection with the embodiments disclosed herein can be implemented in hardware, computer-readable software, firmware, or any practical combination thereof. To illustrate this interchangeability and compatibility of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps are described generally in terms of their functionality. The embodiments described herein can be implemented in a suitable manner for each particular application, but any implementation decisions should not be interpreted as limiting the scope of the present disclosure.

In accordance with some embodiments, the UE transceiver <NUM> includes a radio frequency (RF) transmitter and a RF receiver each including circuitry that is coupled to the antenna <NUM>. A duplex switch (not shown) may alternatively couple the RF transmitter or receiver to the antenna in time duplex fashion. Similarly, in accordance with some embodiments, the transceiver <NUM> includes an RF transmitter and a RF receiver each having circuity that is coupled to the antenna <NUM> or the antenna of another BS. A duplex switch may alternatively couple the RF transmitter or receiver to the antenna <NUM> in time duplex fashion. The operations of the two-transceiver modules <NUM> and <NUM> can be coordinated in time such that the receiver circuitry is coupled to the antenna <NUM> for reception of transmissions over a wireless transmission link at the same time that the transmitter is coupled to the antenna <NUM>.

The UE transceiver <NUM> and the transceiver <NUM> are configured to communicate via the wireless data communication link, and cooperate with a suitably configured RF antenna arrangement <NUM>/<NUM> that can support a particular wireless communication protocol and modulation scheme. In some illustrative embodiments, the UE transceiver <NUM> and the transceiver <NUM> are configured to support industry standards such as the Long Term Evolution (LTE) and emerging <NUM> standards, and the like. 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 transceiver <NUM> and the transceiver of another BS (such as but not limited to, the transceiver <NUM>) are configured to communicate via a wireless data communication link, and cooperate with a suitably configured RF antenna arrangement that can support a particular wireless communication protocol and modulation scheme. In some illustrative embodiments, the transceiver <NUM> and the transceiver of another BS are configured to support industry standards such as the LTE and emerging <NUM> standards, and the like. Rather, the transceiver <NUM> and the transceiver of another BS may be configured to support alternate, or additional, wireless data communication protocols, including future standards or variations thereof.

In accordance with various embodiments, the BS <NUM> may be a BS such as but not limited to, an eNB, a serving eNB, a target eNB, a femto station, or a pico station, for example. The BS <NUM> can be an RN, a regular , a DeNB, or a gNB.

Furthermore, the method or algorithm disclosed herein can be embodied directly in hardware, in firmware, in a software module executed by processor modules <NUM> and <NUM>, respectively, or in any practical combination thereof.

The network communication module <NUM> generally represents the hardware, software, firmware, processing logic, and/or other components of the BS <NUM> that enable bidirectional communication between the transceiver <NUM> and other network components and communication nodes in communication with the BS <NUM>. For example, the network communication module <NUM> may be configured to support internet or WiMAX traffic. In a deployment, without limitation, the network communication module <NUM> provides an <NUM> Ethernet interface such that the transceiver <NUM> can communicate with a conventional Ethernet based computer network. In some embodiments, the network communication module <NUM> includes a fiber transport connection configured to connect the BS <NUM> to a core network.

Claim 1:
A wireless communication method, comprising:
applying, by a base station, code sequences to repetitions of broadcast information of a plurality of resources of a cell of the base station, each of the code sequences being specific to a corresponding one of the plurality of resources;
transmitting, by the base station to a wireless communication device, the repetitions of the broadcast information with the code sequences applied;
wherein the method is characterised by:
transmitting, by the base station to the wireless communication device, a parameter corresponding to a number of neighboring resources of the cell to be measured; and
receiving, by base station from the wireless communication device, measurements for the number of neighboring resources, wherein the measurements are performed by the wireless communication device using the resource-specific codes sequence.