Non-volatile computer readable medium and method for beam searching

Abstract

To provide non-volatile computer readable media and a method for beam searching.SOLUTION: A method for beam searching suitable for user equipment (UE) is provided. The UE stores a cell ID and a synchronization signal block (SSB) of a previous network connection with base station connected previously. The method includes the following steps. A reconnection to the base station is performed. The cell ID and the SSB of the previous network connection with the previously connected base station are read. Information of the cell ID and the SSB is transmitted to a first base station via a physical random access channel (PRACH). An initial access to the first base station is performed by the UE through the cell ID and the SSB in response to the cell ID in the PRACH received by the first base station matching a preset cell ID configured by the previously connected base station.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a beam management method, and more particularly to a high-speed beam search method and a communication system using the same. [Background technology]

[0002] The beam management process is used in the 5G New Radio (NR) Frequency Range 2 (FR2) to acquire and maintain a set of beams that can be used for downlink (DL) and uplink (UL) transmission / reception of a transmit / receive point (TRxP) and / or user equipment (UE). The 5G New Radio beam management process includes beam scanning, beam measurement, beam determination, and beam reporting. Beam scanning refers to covering a certain spatial region with a set of beams that are transmitted and received at pre-specified intervals and directions. After the UE completes the beam measurement, beam determination, and beam reporting processes, the base station (e.g., gNB) can set the UE's uplink and downlink beams via synchronization signal blocks (SSBs) based on the report results from the UE.

[0003] However, when the UE is in initial access, the base station performs beam scanning from the first SSB to the last SSB to select the optimal beam to synchronize the UE, which process wastes TRxP and the UE's time and power. Summary of the Invention [Problem to be solved by the invention]

[0004] To solve the above problems, the present invention provides a method including storing an optimal SSB pattern in a UE, defining a reference signal received power (RSRP) for initial attach, and changing the beam pattern sequence of a base station. [Means for solving the problem]

[0005] One embodiment of the present invention provides a beam search method suitable for use by a user equipment (UE). The UE stores a cell identifier (ID) and a synchronization signal block (SSB) of a previous network connection with a previously connected base station. The method includes the following steps: first, a reconnection with a first base station is performed; then, the cell ID and the SSB of the previous network connection with the previously connected base station are read; and the cell ID and SSB information are transmitted to the first base station via a physical random access channel (PRACH). In response to the cell ID received by the first base station in the PRACH matching a preset cell ID set by the previously connected base station, the UE performs initial access to the first base station using the cell ID and the SSB.

[0006] An embodiment of the present invention further provides a beam search method, which includes the following steps: Detecting a plurality of synchronization signal blocks (SSBs) transmitted by a base station; Each SSB corresponds to a different beam direction, and the beam widths of the SSBs may be the same or different; Measuring the received signal strength of each SSB; Selecting at least one of the SSBs according to the received signal strength, the beam width, or both; A Physical Random Access Channel (PRACH) is used to transmit information of the SSBs to the base station; Initial access to the base station is performed via the SSBs.

[0007] An embodiment of the present invention further provides a non-transitory computer-readable medium storing one or more instructions executed by one or more processors of a UE networked with a base station. The one or more instructions include the following operations: First, a reconnection of the UE with a first base station is performed; A cell ID and an SSB of a previous network connection with the previously connected base station are read; Next, information of the cell ID and the SSB is transmitted to the first base station via a physical random access channel (PRACH); Initial access to the first base station is performed by the UE using the cell ID and the SSB in response to the cell ID in the PRACH received by the first base station matching a preset cell ID set by the previously connected base station. [Effects of the Invention]

[0008] The present invention effectively saves the time required for the UE and the base station to perform initial access, and also effectively reduces the power consumption of the UE. [Brief explanation of the drawings]

[0009] The present disclosure may be more fully understood from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosure.

[0010] [Figure 1] 1 is a flowchart of a beam search method according to some embodiments of the present invention. [Figure 2] 1 is a flowchart of a beam search method according to some embodiments of the present invention. [Figure 3] 1 is a flowchart of a beam search method according to some embodiments of the present invention. [Figure 4] 4 illustrates a communication system 400 for performing the beam searching method of FIG. 2 according to some embodiments of the present invention. [Figure 5A] 5 illustrates a communication system 500 for implementing the beam searching method of FIG. 3 according to some embodiments of the present invention. [Figure 5B] 5 illustrates a communication system 500 for implementing the beam searching method of FIG. 3 according to some embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] FIG. 1 is a flowchart of a beam search method according to some embodiments of the present invention. The beam search method of the present invention is suitable for a UE. In some embodiments, the UE may be, for example, a laptop, a tablet, or a smartphone, but the present invention is not limited thereto. In some embodiments of FIG. 1, the UE stores a cell ID and a synchronization signal block (SSB) of a previous network connection with a previously connected base station. In some embodiments, the previously connected base station may be, for example, a 5G base station such as a gNB, but the present invention is not limited thereto. The beam search method includes the following steps: First, reconnection with a first base station is performed (step S100). The cell ID and SSB of the previous network connection with the previously connected base station are read (step S102). Information of the cell ID and SSB is transmitted to the first base station via a physical random access channel (PRACH) (step S104). The first base station determines whether the cell ID in the PRACH matches a preset cell ID set by the previously connected base station (step S106). An initial access to the first base station is performed by the UE using the cell ID and the SSB in response to the cell ID matching the preset cell ID (step S108).

[0012] In steps S100 and S102, the cell ID and SSB of the UE's previous network connection with the previously connected base station are stored in non-volatile memory. Therefore, even after the UE completes reboot, the UE can read the cell ID and SSB used for the previous network connection with the previously connected base station. In some embodiments, if the UE does not perform a reboot but simply turns its network function off and then on again, or moves from a location without network service to a location with network service, the cell ID and SSB of the UE's previous network connection with the previously connected base station can be stored in the volatile memory of the UE, but this is not a limitation of the present invention.

[0013] In some embodiments, the SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel (PBCH), and a demodulation reference signal (DMRS). The DMRS associated with the PBCH is used to estimate the reference signal received power (RSRP). The RSRP is calculated based on the SSB received by the UE in a beam measurement phase, and the optimal beam for the UE is selected in a beam determination phase.

[0014] In steps S104 and S106, after the first base station receives the cell ID and SSB information in the PRACH transmitted by the UE in step S104, the first base station determines whether the cell ID in the PRACH matches the preset cell ID configured by the previously connected base station. Since the UE transmits the cell ID and SSB information to all neighboring base stations via the PRACH, only the first base station identifies that the cell ID from the UE matches the preset cell ID configured by the previously connected base station (i.e., step S106: YES), and the first base station configures the UE, so that the UE can perform step S108. In some embodiments of FIG. 1, the beam search method of the present invention further includes the following steps: In response to the cell ID in the PRACH not matching the preset cell ID (i.e., step S106: NO), the beam search method of the present invention performs step S2 of FIG. 2 or step S3 of FIG. 3 (step S110). Steps S100 to S108 in FIG. 1 omit the beam scanning phase, allowing the UE to quickly complete initial access to the base station.

[0015] 2 is a flowchart of a beam search method according to some embodiments of the present invention. The beam search method of the present invention includes the following steps: In response to the cell ID in the PRACH not matching the preset cell ID set by the previously connected base station, multiple updated SSBs transmitted by the second base station are detected, and the received signal strengths of the updated SSBs are measured in order (step S200). It is determined whether the received signal strength of one of the multiple updated SSBs is higher than a threshold (step S202). If the received signal strength of one of the multiple updated SSBs is higher than the threshold (i.e., step S202: YES), information of the one of the multiple updated SSBs is transmitted to the second base station via the PRACH (step S204). Initial access to the second base station is performed via one of the multiple updated SSBs (step S206). If the received signal strength of one of the updated SSBs is not higher than the threshold (i.e., step S202: NO), the beam searching method of the present invention executes step S200 again. In step S200, the second base station transmits multiple updated SSBs at each time interval (e.g., 20 milliseconds). Each updated SSB corresponds to a different beam direction, and the SSBs have the same or different beam widths. The received signal strength may be, for example, RSRP, but the present invention is not limited thereto.

[0016] In step S202, the threshold may be, for example, -90 dBm, but the present invention is not limited thereto. In some embodiments, the threshold may be equal to the UE's minimum receiver sensitivity plus a definition threshold. The minimum receiver sensitivity refers to the minimum signal strength that the product antenna can receive from the network. If the signal strength is lower than this, the product will not receive the signal. The definition threshold is defined based on the product's RF performance. In step S202, the UE selects the first updated SSB that exceeds the threshold. This approach can avoid measuring all updated SSBs. As long as one of the multiple updated SSBs exceeds the threshold during the successive measurement period of the updated SSB, information about the one of the multiple updated SSBs is transmitted to the second base station. After the beam search method (or the UE) completes step S204, the second base station configures the UE according to the one updated SSB reported by the UE, and the UE can perform step S206 accordingly.

[0017] In some embodiments of step S202, the UE sequentially measures the received signal strength of one updated SSB among the plurality of updated SSBs, and in response to determining that the received signal strength of the one updated SSB is higher than the threshold, the UE immediately determines that the received signal strength of the one updated SSB is higher than the threshold without measuring the remaining updated SSBs among the plurality of updated SSBs.

[0018] In some embodiments, steps S200 to S206 of FIG. 2 can be independent from steps S100 to S108 of FIG. 1. In other words, there is no need to respond to a mismatch between the cell ID in the PRACH and the preset cell ID in step S106 of FIG. 1. The beam search method can directly perform steps S200 to S206 of FIG. 2. In some embodiments, step S200 may correspond to a beam scanning phase and a beam measurement phase. Step S202 may correspond to a beam determination phase. Step S204 may correspond to a beam reporting phase.

[0019] 3 is a flowchart of a beam search method according to some embodiments of the present invention. The beam search method of the present invention includes the following steps: In response to the cell ID in the PRACH not matching the preset cell ID set by the previously connected base station, multiple wide-beam SSBs transmitted by the second base station are detected, and the received signal strength of each wide-beam SSB is measured (step S300); two wide-beam SSBs with the highest received signal strength are selected from the multiple wide-beam SSBs, and information on the two wide-beam SSBs with the highest received signal strength from the multiple wide-beam SSBs is transmitted to the second base station via the PRACH (step S302); multiple narrow-beam SSBs transmitted by the second base station are detected, and the beam directions of the multiple narrow-beam SSBs are located between the beam directions of two wide-beam SSBs from the multiple wide-beam SSBs, and the received signal strength of each narrow-beam SSB from the multiple narrow-beam SSBs is measured (step S304). One narrow beam SSB having the highest received signal strength among the plurality of narrow beam SSBs is selected, and information about the one narrow beam SSB having the highest received signal strength among the plurality of narrow beam SSBs is transmitted to the second base station (step S306). Initial access to the second base station is performed via the one narrow beam SSB (step S308). In steps S300 and S304, the second base station transmits a plurality of wide beam SSBs and a plurality of narrow beam SSBs at each time interval (e.g., 20 milliseconds).

[0020] In step S302, the beam search method of the present invention selects two wide-beam SSBs with the highest received signal strengths from the plurality of wide-beam SSBs. The two wide-beam SSBs with the highest received signal strengths from the plurality of wide-beam SSBs are used to determine a coarse beam direction based on the relative position between the UE and the second base station. After the coarse direction is determined, in step S304, the beam search method of the present invention measures the received signal strengths of the plurality of narrow-beam SSBs. The beam direction of the plurality of narrow-beam SSBs is located between the beam directions of two wide-beam SSBs from the plurality of wide-beam SSBs. In step S306, the beam search method of the present invention selects one narrow-beam SSB with the highest received signal strength from the plurality of narrow-beam SSBs to determine a precise direction. After completing step S306, the second base station configures the UE according to the one narrow-beam SSB reported by the UE, and the UE can perform step S308 accordingly.

[0021] In some embodiments, steps S300 to S308 of FIG. 3 can be independent from steps S100 to S108 of FIG. 1. In other words, there is no need to respond to a mismatch between the cell ID in the PRACH and the preset cell ID in step S106 of FIG. 1. The beam search method can directly perform steps S300 to S308 of FIG. 3. In some embodiments, steps S300 and S304 may correspond to a beam scanning phase and a beam measurement phase. Steps S302 and S306 may correspond to a beam determination phase. Steps S302 and S306 may correspond to a beam reporting phase.

[0022] FIG. 4 illustrates a communication system 400 that performs the beam search method of FIG. 2 in accordance with some embodiments of the present invention. Some embodiments of FIG. 4 are scenarios applied to 5G New Radio (NR). As illustrated in FIG. 4, the communication system 400 includes a UE 402, a UE 404, and a base station 406. In some embodiments, the UE 402 and the UE 404 may be, for example, a laptop, a tablet, and a smartphone, but the present invention is not limited thereto. The base station 406 may be, for example, a 5G base station such as a gNB. The base station 406 transmits multiple SSBs to the UE 402 and the UE 404 every 20 milliseconds. As illustrated in FIG. 4, the base station 406 transmits four sets of SSBs to the UE 402 and the UE 404 within 80 milliseconds. Taking the third set of SSBs from left to right as an example, the third set of SSBs includes eight SSBs within 5 milliseconds, corresponding to SSB indexes 0 to 7, respectively. Each SSB in the third set corresponds to a different beam direction.

[0023] When the UE 402 and the UE 404 receive SSBs with SSB indices 0 through 7, the UE 402 and the UE 404 measure the received signal strength of the SSBs with SSB indices 0 through 7 in order. In some embodiments, the received signal strength may be RSRP. For example, when the UE 402 measures that the received signal strength of the SSB with SSB index 1 is higher than the threshold 410, the UE 402 does not need to continue measuring the received signal strength of the subsequent SSB indices 2 through 7. The UE 402 selects the SSB with SSB index 1 and transmits information about the SSB with SSB index 1 to the base station 406 via the PRACH. After the base station 406 receives the information about the SSB with SSB index 1, the base station 406 configures the UE 402 so that the UE 402 performs initial access to the base station 406 via the SSB with SSB index 1.

[0024] Similarly, after completing measurements of the SSB received signal strengths of SSBs with SSB indices 0 to 5, if the UE 404 measures that the received signal strength of the SSB with SSB index 6 is higher than threshold 410, the UE 404 does not need to continue measuring the received signal strength of the subsequent SSB with SSB index 7. The UE 404 selects the SSB with SSB index 6 and transmits information about the SSB with SSB index 6 to the base station 406 via the PRACH. After the base station 406 receives the information about the SSB with SSB index 6, the base station 406 configures the UE 404 so that the UE 404 performs initial access to the base station 406 via the SSB with SSB index 6. In some embodiments, threshold 410 may be, for example, −90 dBm, although the present invention is not limited thereto. In some embodiments, the UE 404 measures the received signal strength of each SSB of the plurality of SSBs in turn, and in response to determining that the received signal strength of the SSB having SSB index 6 is higher than the threshold, the UE 404 immediately determines that the received signal strength of the SSB having SSB index 6 is higher than the threshold without measuring the remaining SSBs of the plurality of SSBs.

[0025] 5A and 5B illustrate a communication system 500 for the beam searching method of FIG. 3 according to some embodiments of the present invention. Some embodiments of FIGS. 5A and 5B are scenarios applied to 5G New Radio (NR). As shown in FIG. 5B, the communication system 500 includes a UE 502 and a base station 504. In some embodiments, the UE 502 may be, for example, a laptop, a tablet, or a smartphone, but the present invention is not limited thereto. The base station 504 may be, for example, a 5G base station such as a gNB. In FIG. 5A, the base station 504 transmits multiple SSBs to the UE 502 every 20 milliseconds. As shown in FIG. 5A, the base station 504 transmits four sets of SSBs to the UE 502 within 80 milliseconds. Taking the third set of SSBs from left to right as an example, the third set of SSBs includes three SSBs within two milliseconds and two SSBs within the following one millisecond, which correspond to SSB indices 1, 4, 7, 2, and 3, respectively. That is, each SSB in the third set of SSBs corresponds to a different beam direction. In some embodiments of FIG. 5A, the SSBs with SSB indices 1, 4, and 7 are wide-beam SSBs. The SSBs with SSB indices 2 and 3 are narrow-beam SSBs.

[0026] Specifically, the UE 502 detects SSBs with SSB indices 1, 4, and 7 from the base station 504 and measures the received signal strengths of the SSBs with SSB indices 1, 4, and 7. The UE 502 then determines that the SSBs with SSB indices 1 and 4 have the highest received signal strengths. Accordingly, the UE 502 selects the SSBs with SSB indices 1 and 4 and transmits information about the SSBs with SSB indices 1 and 4 to the base station 504 via the PRACH. In some embodiments, the received signal strength may be RSRP, although the present invention is not limited thereto. The SSBs with SSB indices 1 and 4 may correspond, for example, to wide-beam SSB1 and wide-beam SSB4 in FIG. 5B, respectively. The SSB with SSB index 7 may correspond, for example, to wide-beam SSB7 in FIG. 5B.

[0027] When base station 504 receives information about SSBs with SSB indexes 1 and 4, base station 504 transmits SSBs with SSB indexes 2 and 3 to UE 502. The SSB with SSB index 2 corresponds to narrow beam SSB2 in FIG. 5B. The SSB with SSB index 3 corresponds to narrow beam SSB3 in FIG. 5B. In some embodiments of FIG. 5B, the beam directions of narrow beam SSB2 and SSB3 are between the beam directions of wide beam SSB1 and SSB4. Then, in FIG. 5A, UE 502 detects SSBs with SSB indexes 2 and 3 and measures the received signal strength of the SSBs with SSB indexes 2 and 3.

[0028] 5A and 5B, the UE 502 only needs to measure the received signal strength of wide-beam SSB1 (SSB index 1), wide-beam SSB4 (SSB index 4), wide-beam SSB7 (SSB index 7), narrow-beam SSB2 (SSB index 2), and narrow-beam SSB3 (SSB index 3). Ignoring other SSBs (e.g., SSB index 5 and SSB index 6) transmitted by base station 504 effectively saves the time for UE 502 and base station 504 to perform initial access, and also effectively reduces the power consumption of UE 502.

[0029] Taking several embodiments of Figures 4, 5A, and 5B together, the beam searching method of the present invention includes the following steps: Detecting multiple SSBs transmitted by a base station; Each SSB corresponds to a different beam direction, and the beam width of each SSB may be the same or different; Measuring the received signal strength of each SSB; Selecting at least one SSB according to at least one of the received signal strength and the beam width; Using PRACH to transmit information of the SSBs to the base station; Initial access to the base station is performed via the SSBs.

[0030] The present invention further provides a non-transitory computer-readable medium storing one or more instructions for execution by one or more processors of a UE networked with a base station, the one or more instructions comprising the following operations: reconnecting the UE to a first base station; reading a cell ID and an SSB of a previous network connection with the previously connected base station; transmitting the cell ID and SSB information to the first base station via a PRACH; and, in response to the cell ID in the PRACH received by the first base station matching a preset cell ID set by the previously connected base station, performing initial access to the first base station using the cell ID and the SSB.

[0031] In some embodiments, in response to the cell ID in the PRACH not matching the preset cell ID configured by the previously serving base station, the one or more instructions include the following actions: Detecting a plurality of updated SSBs transmitted by the second base station; Measuring the received signal strength of the updated SSBs in sequence; Determining that the received signal strength of one updated SSB of the plurality of updated SSBs is higher than a threshold; Transmitting information of the one updated SSB via the PRACH to the second base station; and Performing initial access to the second base station via the one updated SSB.

[0032] In some embodiments, in response to sequentially measuring the received signal strength of one updated SSB of the plurality of updated SSBs and determining that the received signal strength of the one updated SSB is higher than a threshold, the one or more instructions include the following actions: immediately determining that the received signal strength of the one updated SSB is higher than a threshold without measuring the remaining updated SSBs of the plurality of updated SSBs.

[0033] In some embodiments, in response to the cell ID in the PRACH not matching the preset cell ID set by the previously connected base station, the one or more instructions include the following actions: Detecting a plurality of wide beam SSBs transmitted by the second base station; Measuring the received signal strength of each wide beam SSB; Selecting the two wide beam SSBs with the highest received signal strengths; Using the PRACH to transmit information of the two wide beam SSBs with the highest received signal strengths to the second base station; Detecting a plurality of narrow beam SSBs transmitted by the second base station; The beam direction corresponding to the narrow beam SSB is between the beam directions corresponding to the two wide beam SSBs; Measuring the received signal strength of each narrow beam SSB; Selecting one of the narrow beam SSBs with the highest received signal strengths; Using the PRACH to transmit information of the narrow beam SSB with the highest received signal strength to the second base station; Initial access to the second base station is performed via the narrow beam SSBs.

[0034] In some embodiments, the received signal strength comprises an RSRP, and the threshold comprises a minimum receiver sensitivity of the UE. [Industrial Applicability]

[0035] The present disclosure applies to a UE in a communication system by means of a non-transitory computer-readable medium storing one or more instructions for execution by one or more processors in the UE. [Explanation of symbols]

[0036] S100, S102, S104, S106, S108, S110, S200, S202, S204, S206, S300, S302, S304, S306, S308 Process 400, 500 communication systems 402, 404, 502 User Equipment (UE) 406, 504 base station 410 Threshold SSB1, SSB4, SSB7 wide beam SSB2, SSB3 narrow beam

Claims

1. A beam search method for a user equipment (UE), wherein the UE has stored a cell identifier (ID) and a synchronization signal block (SSB) of a previous network connection with a base station to which the UE was previously connected, the method comprising: performing a reconnection with the first base station; reading the cell ID and the SSB of a previous network connection with the previously connected base station; transmitting the cell ID and the SSB information to the first base station via a physical random access channel (PRACH); and In response to the cell ID in the PRACH received by the first base station matching a preset cell ID set by the previously connected base station, performing initial access to the first base station by the UE via the cell ID and the SSB; A beam search method comprising:

2. A beam search method for a user equipment (UE), wherein the UE has stored a cell identifier (ID) and a synchronization signal block (SSB) of a previous network connection with a base station to which the UE was previously connected, the method comprising: performing a reconnection with the first base station; reading the cell ID and the SSB of a previous network connection with the previously connected base station; transmitting the cell ID and information of the SSB to the first base station via a physical random access channel (PRACH); In response to the cell ID in the PRACH received by the first base station matching a preset cell ID set by the previously connected base station, performing initial access to the first base station by the UE via the cell ID and the SSB; detecting a plurality of updated SSBs transmitted by a second base station in response to the cell ID in the PRACH not matching the preset cell ID set by the previously connected base station; measuring the received signal strength of the plurality of updated SSBs in sequence; determining that a received signal strength of one updated SSB among the plurality of updated SSBs is greater than a threshold; transmitting information of the one updated SSB among the plurality of updated SSBs to the second base station via the PRACH; and performing the initial access to the second base station via the one updated SSB of the plurality of updated SSBs; A beam search method comprising:

3. A beam search method for a user equipment (UE), wherein the UE has stored a cell identifier (ID) and a synchronization signal block (SSB) of a previous network connection with a base station to which the UE was previously connected, the method comprising: performing a reconnection with the first base station; reading the cell ID and the SSB of a previous network connection with the previously connected base station; transmitting the cell ID and information of the SSB to the first base station via a physical random access channel (PRACH); In response to the cell ID in the PRACH received by the first base station matching a preset cell ID set by the previously connected base station, performing initial access to the first base station by the UE via the cell ID and the SSB; detecting a plurality of wide beam SSBs transmitted by a second base station in response to the cell ID in the PRACH not matching the preset cell ID set by the previously connected base station; measuring a received signal strength of each wide beam SSB of the plurality of wide beam SSBs; selecting two wide beam SSBs having the highest received signal strengths from the plurality of wide beam SSBs; transmitting information of the two wide beam SSBs having the highest received signal strengths among the plurality of wide beam SSBs to the second base station via the PRACH; detecting a plurality of narrow beam SSBs transmitted by the second base station, wherein beam directions of the plurality of narrow beam SSBs are located between beam directions of the two wide beam SSBs of the plurality of wide beam SSBs; measuring a received signal strength of each narrow beam SSB among the plurality of narrow beam SSBs; selecting one narrow beam SSB having the highest received signal strength from the plurality of narrow beam SSBs; transmitting information of the narrow beam SSB having the highest received signal strength among the plurality of narrow beam SSBs to the second base station via the PRACH; performing the initial access to the second base station via the one narrow beam SSB of the plurality of narrow beam SSBs; A beam search method comprising:

4. A beam search method for a user equipment (UE), comprising: detecting a plurality of synchronization signal blocks (SSBs) transmitted by a base station, each of the plurality of SSBs corresponding to a different beam direction, and each of the plurality of SSBs having the same or different beam width; measuring the received signal strength of the plurality of SSBs; selecting at least one SSB from the plurality of SSBs according to at least one of the received signal strength and the beamwidth; transmitting information of the at least one SSB among the plurality of SSBs to the base station via a physical random access channel (PRACH); and performing initial access to the base station via the at least one SSB of the plurality of SSBs; A beam search method comprising:

5. 1. A non-transitory computer-readable medium storing one or more instructions for execution by one or more processors of user equipment (UE) networked with a base station, the one or more instructions comprising: performing a reconnection of the UE to a first base station; reading a cell identifier (ID) and a synchronization signal block (SSB) of a previous network connection with a previously connected base station; transmitting the cell ID and information of the SSB to the first base station via a physical random access channel (PRACH); In response to the cell ID in the PRACH received by the first base station matching a preset cell ID set by the previously connected base station, performing initial access to the first base station by the UE via the cell ID and the SSB; and In response to the cell ID in the PRACH not matching the preset cell ID set by the previously connected base station, the one or more instructions: detecting a plurality of updated SSBs transmitted by a second base station; measuring the received signal strength of the plurality of updated SSBs in sequence; determining that a received signal strength of one updated SSB among the plurality of updated SSBs is greater than a threshold; transmitting information of the one updated SSB among the plurality of updated SSBs to the second base station via the PRACH; performing the initial access to the second base station via the one updated SSB of the plurality of updated SSBs; 1. A non-transitory computer-readable medium comprising:

6. 1. A non-transitory computer-readable medium storing one or more instructions for execution by one or more processors of user equipment (UE) networked with a base station, the one or more instructions comprising: performing a reconnection of the UE to a first base station; reading a cell ID and a synchronization signal block (SSB) of a previous network connection with a previously connected base station; transmitting the cell ID and information of the SSB to the first base station via a physical random access channel (PRACH); In response to the cell ID in the PRACH received by the first base station matching a preset cell ID set by the previously connected base station, performing initial access to the first base station by the UE via the cell ID and the SSB; and In response to the cell ID in the PRACH not matching the preset cell ID set by the previously connected base station, the one or more instructions: detecting a plurality of wide beam SSBs transmitted by a second base station; measuring a received signal strength of each wide beam SSB of the plurality of wide beam SSBs; selecting two wide beam SSBs having the highest received signal strengths from the plurality of wide beam SSBs; transmitting information of the two wide beam SSBs having the highest received signal strengths among the plurality of wide beam SSBs to the second base station via the PRACH; detecting a plurality of narrow beam SSBs transmitted by the second base station, wherein beam directions of the plurality of narrow beam SSBs are located between beam directions of the two wide beam SSBs of the plurality of wide beam SSBs; measuring a received signal strength of each narrow beam SSB among the plurality of narrow beam SSBs; selecting one narrow beam SSB having the highest received signal strength from the plurality of narrow beam SSBs; transmitting information of the narrow beam SSB having the highest received signal strength among the plurality of narrow beam SSBs to the second base station via the PRACH; performing the initial access to the second base station via the one narrow beam SSB of the plurality of narrow beam SSBs; 1. A non-transitory computer-readable medium comprising:

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