Method and device for rapidly switching BWP

Abstract

The invention discloses a method for quickly switching a BWP (Broadband Wireless Protocol) of a mobile communication system. And the base station sends the downlink DCI for indicating the switching of the BWP and the PDSCH scheduled by the downlink DCI to the terminal on the source BWP. And the terminal receives the downlink DCI for indicating the switching of the BWP and the PDSCH scheduled by the downlink DCI on the source BWP, and decodes the received PDSCH. And if the decoding is successful, the terminal immediately switches to the target BWP specified by the downlink DCI for indicating the BWP switching. And the terminal sends HARQ feedback to the base station on the target BWP. And the base station receives HARQ feedback on the target BWP and judges whether the terminal switches the BWP successfully or not. According to the invention, the reliability problem of BWP switching based on a DCI mode is solved, the BWP switching time delay and the protocol are almost equal or even faster, and the degree of parallelism is improved.

Description

Technical Field

[0001] This application relates to a mobile communication technology, and more particularly to a BWP (bandwidth part) switching method. Background Technology

[0002] BWP is a concept proposed by 5G NR (new radio) mobile communication systems. For the same UE (user equipment), only one BWP can be active at any given time, whether it is in the downlink or uplink. The UE performs data transmission and reception and PDCCH (physical downlink control channel) retrieval on this active BWP.

[0003] In existing NR mobile communication systems, the gNB (next generation Node B) can proactively send BWP handover commands to the UE through two methods: RRC (radio resource control) messages and DCI (downlink control information). The DCI-based BWP handover method works as follows: the gNB sends a DCI indicating BWP handover to the UE from the source BWP. The UE correctly demodulates this DCI to obtain the target BWP information. Specifically, the DCI indicating BWP handover contains the scheduled BWP index (i.e., the target BWP). When the scheduled BWP index is inconsistent with the UE's current BWP index, the UE needs to switch to the scheduled BWP index. The DCI indicating BWP handover includes DCI formats 0_1, 0_2, 0_3, 1_1, 1_2, and 1_3, etc.

[0004] DCI formats 0_1, 0_2, and 0_3 belong to uplink DCI and are used to provide scheduling information for PUSCH (physical uplink shared channel). After receiving it, the UE sends the PUSCH to the gNB on the target BWP, and the gNB receives the PUSCH on the target BWP.

[0005] DCI formats 1_1, 1_2, and 1_3 belong to downlink DCI and are used to provide scheduling information for PDSCH (physical downlink shared channel). After receiving the PDSCH, the UE receives the PDSCH sent by the gNB on the target BWP and sends HARQ (hybrid auto repeat request) to the gNB. The gNB receives the HARQ on the target BWP.

[0006] The above DCI-based BWP switching method has the following drawbacks.

[0007] First, the UE might falsely detect a DCI indicating a BWP handover, when the gNB has not actually sent that DCI to the UE. In this case, the UE incorrectly switches to a different BWP, while the gNB still believes the UE is in its original BWP, leading to a communication service interruption. Due to this flaw of false DCI detection, existing NR mobile communication systems rarely use the gNB to schedule UE BWP handover via DCI.

[0008] Second, when the gNB faces two tasks simultaneously, namely "BWP handover" and "data or signaling with higher priority that needs to be sent to the UE", the PDSCH corresponding to the "DCI indicating BWP handover" needs to be sent on the target BWP. The gNB can either send the higher priority data or signaling to the UE first and then schedule the BWP handover after completion, or schedule the BWP handover first and then send the higher priority data or signaling to the UE after completion. The two tasks cannot be executed at the same time.

[0009] In summary, DCI-based BWP switching methods have shortcomings in reliability and parallel task processing, while RRC message-based BWP switching methods are too slow. This results in the current lack of a relatively reliable and fast method for scheduling BWP switching. Summary of the Invention

[0010] The technical problem to be solved by this application is: how to improve the reliability of DCI-based BWP handover, maintain its low BWP handover latency, and improve task parallelism.

[0011] To address the aforementioned technical problems, this application proposes a method for rapid BWP handover in a mobile communication system, comprising the following steps: the BWP before handover is referred to as the source BWP, and the BWP after handover is referred to as the target BWP. Step S1: The base station sends a downlink DCI indicating BWP handover and a PDSCH scheduled by the downlink DCI to the terminal on the source BWP; the downlink DCI indicating BWP handover records information about the target BWP and scheduling information for the PDSCH, wherein the PDSCH scheduling information is the time-domain and frequency-domain resources of the PDSCH allocated on the source BWP. Step S2: The terminal receives the downlink DCI indicating BWP handover on the source BWP, obtains the information about the target BWP and the PDSCH scheduling information from it, and receives the PDSCH scheduled by the downlink DCI indicating BWP handover on the source BWP according to the PDSCH scheduling information, and decodes the received PDSCH. If the terminal successfully decodes the PDSCH, it determines that the received downlink DCI indicating BWP handover is genuine, and immediately switches to the target BWP specified by the downlink DCI, then proceeds to step S3. If the terminal fails to decode the PDSCH, it determines that the received downlink DCI indicating BWP handover is a false alarm, and the terminal remains on the source BWP. Step S3: The terminal sends HARQ feedback to the base station on the target BWP. Step S4: The base station receives the HARQ feedback on the target BWP and determines whether the terminal's BWP handover was successful.

[0012] For example, the downlink DCI indicating BWP switching includes any one of DCI format 1_1, DCI format 1_2 and DCI format 1_3.

[0013] This application also proposes a method for fast BWP handover on the base station side, including the following steps. Step S21: The base station schedules the downlink DCI indicating BWP handover on the source BWP, and the PDSCH scheduled by the downlink DCI indicating BWP handover is also scheduled by the base station on the source BWP. The downlink DCI indicating BWP handover records a first timeslot offset, which is used to indicate how many timeslots the base station waits after sending the downlink DCI indicating BWP handover before sending the PDSCH scheduled by the downlink DCI indicating BWP handover. The downlink DCI indicating BWP handover also records a second timeslot offset, which is used to indicate how many timeslots the terminal waits after receiving the PDSCH data before sending the corresponding HARQ feedback. Step S22: The base station sends the downlink DCI indicating BWP handover and its scheduled PDSCH to the terminal on the source BWP, and the transmission interval of the two follows the first timeslot offset; whether the decoding of the PDSCH on the terminal side is successful or not is used to determine whether the downlink DCI indicating BWP handover is a false detection, and to determine whether to switch to the target BWP. Step S23: The base station receives the HARQ feedback sent by the terminal at the time calculated based on the second time slot offset on the target BWP; if the base station receives the HARQ feedback, it determines that the terminal's BWP handover is successful; if the base station does not receive the HARQ information, it determines that the terminal's BWP handover has failed.

[0014] Furthermore, the time-domain resource allocation field in the downlink DCI indicating BWP switching records a first time slot offset.

[0015] Furthermore, the PDSCH to HARQ feedback timing indication field in the downlink DCI indicating BWP switching records a second time slot offset.

[0016] This application also proposes a method for fast BWP handover on the terminal side, including the following steps: Step S31: The terminal receives a downlink DCI indicating BWP handover sent by the base station on the source BWP; the terminal parses the downlink DCI indicating BWP handover to obtain a first timeslot offset and a second timeslot offset; the first timeslot offset is used to indicate how many timeslots after the base station sends the PDSCH scheduled by the downlink DCI indicating BWP handover; the second timeslot offset is used to indicate how many times slots after the terminal receives the PDSCH data to send the corresponding HARQ feedback. Step S32: The terminal receives the PDSCH sent by the base station on the source BWP at the time when the base station sends the PDSCH calculated according to the first timeslot offset. Step S33: The terminal decodes the received PDSCH. If the terminal successfully decodes the PDSCH, the terminal determines that the received downlink DCI indicating BWP handover is real, and the terminal immediately switches to the target downlink BWP specified by the downlink DCI indicating BWP handover, and then proceeds to step S34. If the terminal fails to decode the PDSCH, the terminal determines that the received downlink DCI indicating BWP handover is a false detection, and the terminal continues to remain on the source BWP. Step S34: After successfully handing over the BWP, the terminal sends HARQ feedback to the base station on the target BWP at the time calculated based on the second time slot offset; whether the HARQ feedback is successfully received on the base station side is used to determine whether the terminal's BWP handover was successful.

[0017] Furthermore, in step S33, when the terminal switches to the target downlink BWP, for asymmetric spectrum, the terminal simultaneously switches the uplink active BWP to the uplink BWP associated with the downlink target BWP; for symmetric spectrum, when the terminal selects a paired configuration of uplink and downlink BWPs, the terminal simultaneously switches the uplink active BWP to the uplink BWP with the same identification number as the downlink BWP.

[0018] This application also proposes a fast BWP handover apparatus, comprising a base station and a terminal. The base station is used to send a downlink DCI indicating BWP handover and a PDSCH scheduled by the downlink DCI to the terminal from the source BWP; the downlink DCI indicating BWP handover records information about the target BWP and PDSCH scheduling information, wherein the PDSCH scheduling information is the time-domain and frequency-domain resources of the PDSCH allocated on the source BWP; the base station is also used to receive HARQ feedback on the target BWP to determine whether the terminal's BWP handover was successful. The terminal is configured to receive the downlink DCI indicating BWP handover on the source BWP, obtain information about the target BWP and the scheduling information of the PDSCH from it, and receive the PDSCH scheduled by the downlink DCI indicating BWP handover on the source BWP according to the scheduling information of the PDSCH, and decode the received PDSCH; if the terminal successfully decodes the PDSCH, the terminal determines that the received downlink DCI indicating BWP handover is real, and the terminal immediately switches to the target BWP specified by the downlink DCI indicating BWP handover; after the terminal successfully switches to the target BWP, the terminal sends HARQ feedback to the base station on the target BWP; if the terminal fails to decode the PDSCH, the terminal determines that the received downlink DCI indicating BWP handover is a false detection, and the terminal continues to remain on the source BWP.

[0019] This application also proposes a base station for fast BWP handover, including a scheduling unit, a transmitting unit, and a receiving and judging unit. The scheduling unit is used to schedule the downlink DCI indicating BWP handover onto the source BWP; the PDSCH scheduled by the downlink DCI indicating BWP handover is also scheduled onto the source BWP by the scheduling unit. The transmitting unit is used to transmit the downlink DCI indicating BWP handover and its scheduled PDSCH to the terminal from the source BWP; the success or failure of the decoding of the PDSCH on the terminal side is used to determine whether the downlink DCI indicating BWP handover is a false detection and to decide whether to switch to the target BWP. The receiving and judging unit is used to receive HARQ feedback sent by the terminal on the target BWP; if HARQ feedback is received, the receiving and judging unit determines that the terminal's BWP handover is successful; if no HARQ feedback is received, the receiving and judging unit determines that the terminal's BWP handover has failed.

[0020] This application also proposes a terminal for fast BWP handover, including a receiving unit, a decoding unit, a BWP handover unit, and a HARQ feedback unit. The receiving unit is used to receive a downlink DCI indicating BWP handover sent by the base station on the source BWP, and also to receive a PDSCH scheduled by the downlink DCI indicating BWP handover sent by the base station on the source BWP. The decoding unit is used to decode the received PDSCH. The BWP handover unit is used to immediately switch to the target BWP specified by the downlink DCI indicating BWP handover when the PDSCH decoding is successful; and also to remain on the source BWP when the PDSCH decoding fails. The HARQ feedback unit is used to send HARQ feedback to the base station on the target BWP after successful BWP handover; whether the HARQ feedback is successfully received at the base station is used to determine whether the terminal's BWP handover was successful.

[0021] The technical effects achieved by this application are: it solves the reliability problem of BWP handover based on DCI, and the BWP handover latency is almost the same as or even faster than that of the protocol; it allows the two tasks of "BWP handover" and "data or signaling with higher priority that needs to be sent to the UE" to be executed in parallel, thereby improving the parallelism of tasks. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the method for achieving rapid BWP switching in a mobile communication system proposed in this application.

[0023] Figure 2 This is a flowchart illustrating the method for implementing fast BWP handover on the base station side proposed in this application.

[0024] Figure 3 This is a flowchart illustrating the method for implementing fast BWP switching on the terminal side proposed in this application.

[0025] Figure 4 This is a schematic diagram of the device for rapidly switching BWP proposed in this application.

[0026] Figure 5 This is a schematic diagram of the base station structure for the fast BWP handover proposed in this application.

[0027] Figure 6 This is a schematic diagram of the terminal for fast BWP switching proposed in this application.

[0028] The following are the reference numerals in the figure: Base station 10, scheduling unit 11, transmitting unit 12, receiving and judging unit 13, terminal 20, receiving unit 21, decoding unit 22, BWP switching unit 23, and HARQ feedback unit 24. Detailed Implementation

[0029] Please see Figure 1 The method for achieving rapid BWP handover in a mobile communication system proposed in this application includes the following steps. The BWP before handover is called the source BWP, and the BWP after handover is called the target BWP.

[0030] Step S1: The base station sends a "downlink DCI indicating BWP handover" and a PDSCH scheduled by the "downlink DCI indicating BWP handover" to the terminal on the source BWP. The "downlink DCI indicating BWP handover" includes any one of DCI format 1_1, DCI format 1_2, and DCI format 1_3, which records the target BWP information and PDSCH scheduling information, and the PDSCH scheduling information is the PDSCH time domain and frequency domain resources allocated on the source BWP.

[0031] Step S2: The terminal receives a "downlink DCI indicating BWP handover" on the source BWP, obtains the target BWP information and PDSCH scheduling information from it, and receives the PDSCH scheduled by the "downlink DCI indicating BWP handover" on the source BWP according to the PDSCH scheduling information, and decodes the received PDSCH.

[0032] If the terminal successfully decodes the PDSCH, the terminal determines that the received "downlink DCI indicating BWP handover" is genuine, and the terminal immediately switches to the target BWP specified by the "downlink DCI indicating BWP handover", and then proceeds to step S3.

[0033] If the terminal fails to decode the PDSCH, the terminal determines that the received "downlink DCI indicating BWP handover" is a false detection, and the terminal continues to remain on the source BWP.

[0034] Step S3: The terminal sends HARQ feedback to the base station on the target BWP.

[0035] Step S4: The base station receives HARQ feedback on the target BWP to determine whether the terminal's BWP handover was successful. The specific determination method will be explained in detail in subsequent step S23.

[0036] Please see Figure 2 The method for achieving fast BWP handover on the base station side proposed in this application includes the following steps.

[0037] Step S21: The base station schedules the "downlink DCI indicating BWP handover" on the source BWP. The PDSCH scheduled by the "downlink DCI indicating BWP handover" is also scheduled by the base station on the source BWP.

[0038] The time domain resource assignment field in the "Downlink DCI Indicating BWP Handover" indicates how many time slots the base station waits after sending the "Downlink DCI Indicating BWP Handover" before sending the PDSCH scheduled by the "Downlink DCI Indicating BWP Handover," and is called the first time slot offset. The base station uses the first time slot offset to determine when to send the PDSCH to the terminal. The terminal uses the first time slot offset to determine when to receive the PDSCH sent by the base station.

[0039] The PDSCH-to-HARQ_feedback timing indicator field in the "Downlink DCI indicating BWP handover" indicates how many time slots the terminal waits after receiving PDSCH data before sending the corresponding HARQ feedback; this is called the second time slot offset. The terminal uses the second time slot offset to determine when to send HARQ feedback to the base station. The base station uses the second time slot offset to determine when to receive the HARQ feedback sent by the terminal.

[0040] Step S22: The base station sends a downlink DCI indicating BWP handover and its scheduled PDSCH to the terminal on the source BWP, with the transmission interval of the two following the first time slot offset. Whether the decoding of the PDSCH on the terminal side is successful or not is used to determine whether the downlink DCI indicating BWP handover is a false detection and to decide whether to switch to the target BWP.

[0041] The combination of steps S21 and S22 corresponds to Figure 1 Step S1 in the process.

[0042] Step S23: The base station receives the HARQ feedback sent by the terminal at the time calculated based on the second timeslot offset on the target BWP. If the base station receives the HARQ feedback, it determines that the terminal's BWP handover was successful. If the base station does not receive the HARQ information, it determines that the terminal's BWP handover failed.

[0043] Step S23 corresponds to Figure 1 Step S4 in the process.

[0044] Please see Figure 3 The method for fast BWP switching on the terminal side proposed in this application includes the following steps.

[0045] Step S31: The terminal receives the downlink DCI indicating BWP handover sent by the base station on the source BWP. At this time, the terminal has enabled the fast BWP handover function by default. The terminal obtains the first timeslot offset by parsing and calculates the time when the base station sends the PDSCH. The terminal also obtains the second timeslot offset by parsing and calculates the time to send HARQ feedback to the base station.

[0046] Step S32: The terminal receives the PDSCH sent by the base station on the source BWP at the time when the base station sends the PDSCH calculated based on the first timeslot offset.

[0047] Step S33: The terminal decodes the received PDSCH.

[0048] If the terminal successfully decodes the PDSCH, it determines that the received "downlink DCI indicating BWP handover" is genuine and not a false alarm. The terminal immediately switches to the target downlink BWP specified in the "downlink DCI indicating BWP handover" and then proceeds to step S34. At this point, for asymmetric spectrum, i.e., in the Time Division Duplex (TDD) mode, because uplink and downlink BWPs are configured in pairs, the terminal simultaneously switches the active uplink BWP to the uplink BWP associated with the target downlink BWP. For symmetric spectrum, i.e., in the Frequency Division Duplex (FDD) mode, current communication protocols do not specify that uplink and downlink BWPs are associated with each other and switch simultaneously. Optionally, in the FDD mode, the base station and terminal sides are specified to configure uplink and downlink BWPs in pairs and associate them; in this case, the terminal simultaneously switches the active uplink BWP to the uplink BWP with the same identification number as the downlink BWP.

[0049] If the terminal fails to decode the PDSCH, the terminal determines that the received "downlink DCI indicating BWP handover" is a false detection, and the terminal continues to remain on the source BWP.

[0050] The combination of steps S31 to S33 corresponds to Figure 1 Step S2 in the process.

[0051] Step S34: After successfully switching BWPs, the terminal sends HARQ feedback to the base station on the target BWP at the time calculated based on the second time slot offset. Whether the HARQ feedback is successfully received at the base station is used to determine whether the terminal's BWP switching was successful.

[0052] Step S34 corresponds to Figure 1 Step S3 in the process.

[0053] Optionally, in step S33, if the terminal fails to decode the PDSCH, but the terminal measures that the signal-to-noise ratio (SNR) of the downlink DCI indicating BWP handover and the PDSCH is higher than the SNR threshold, or the terminal detects that the decoding confidence of the downlink DCI indicating BWP handover and the PDSCH is higher than the confidence threshold, it indicates that this PDSCH and the "downlink DCI indicating BWP handover" that scheduled it were actually sent by the base station and are not a false alarm. In this case, the terminal immediately switches to the target BWP specified by the "downlink DCI indicating BWP handover" using the same method as when the PDSCH decoding was successful, and then proceeds to step S34. In step S34, the HARQ feedback sent by the terminal to the base station should be NACK, indicating that the PDSCH decoding failed. The terminal can determine the appropriate SNR threshold and confidence threshold for the DCI and PDSCH based on its demodulation capabilities, decoding algorithm, historical measurements and decoding confidence results, and other measurement results under the current channel environment.

[0054] Please see Figure 4 The device for fast BWP handover proposed in this application consists of a base station 10 and a terminal 20. Figure 4 The device shown corresponds to Figure 1 The method shown.

[0055] The base station 10 is used to send a "downlink DCI indicating BWP handover" and a PDSCH scheduled by the "downlink DCI indicating BWP handover" to the terminal on the source BWP. The base station 10 is also used to receive HARQ feedback on the target BWP to determine whether the BWP handover by the terminal 20 was successful.

[0056] The terminal 20 is used to receive a downlink DCI indicating BWP handover and a PDSCH scheduled by the downlink DCI on the source BWP, and decodes the received PDSCH. If the terminal 20 successfully decodes the PDSCH, the terminal 20 determines that the received downlink DCI indicating BWP handover is genuine, and the terminal 20 immediately switches to the target BWP specified by the downlink DCI indicating BWP handover. After the terminal 20 successfully switches to the target BWP, the terminal 20 sends a HARQ feedback to the base station on the target BWP. If the terminal 20 fails to decode the PDSCH, the terminal 20 determines that the received downlink DCI indicating BWP handover is a false alarm, and the terminal 20 remains on the source BWP.

[0057] Please see Figure 5 The base station 10 for fast BWP switching proposed in this application includes a scheduling unit 11, a transmitting unit 12, and a receiving and judging unit 13. Figure 5 The device shown corresponds to Figure 2 The method shown.

[0058] The scheduling unit 11 is used to schedule the "downlink DCI indicating BWP handover" on the source BWP. The PDSCH of the "downlink DCI indicating BWP handover" is also scheduled on the source BWP by the scheduling unit 11.

[0059] The sending unit 12 is used to send a downlink DCI indicating BWP handover and its scheduling PDSCH to the terminal from the source BWP. Whether the PDSCH is successfully decoded at the terminal is used to determine whether the downlink DCI indicating BWP handover is a false detection and to decide whether to switch to the target BWP.

[0060] The receiving and judging unit 13 is used to receive HARQ feedback sent by the terminal on the target BWP. If HARQ feedback is received, the receiving and judging unit 13 determines that the terminal BWP switching was successful. If no HARQ feedback is received, the receiving and judging unit 13 determines that the terminal BWP switching failed.

[0061] Please see Figure 6 The terminal 20 for fast BWP switching proposed in this application includes a receiving unit 21, a decoding unit 22, a BWP switching unit 23, and a HARQ feedback unit 24. Figure 6 The device shown corresponds to Figure 3 The method shown.

[0062] The receiving unit 21 is used to receive the downlink DCI indicating BWP handover sent by the base station on the source BWP, and is also used to receive the PDSCH scheduled by the "downlink DCI indicating BWP handover" sent by the base station on the source BWP.

[0063] The decoding unit 22 is used to decode the received PDSCH.

[0064] The BWP switching unit 23 is used to immediately switch to the target BWP specified by the "downlink DCI indicating BWP switching" when the PDSCH decoding is successful; it is also used to remain on the source BWP when the PDSCH decoding fails.

[0065] The HARQ feedback unit 24 is used to send HARQ feedback from the target BWP to the base station after a successful BWP handover. Whether the HARQ feedback is successfully received at the base station is used to determine whether the terminal's BWP handover was successful.

[0066] The method proposed in this application requires the terminal to support the fast BWP handover function. Optionally, the base station requires the terminal to report relevant capabilities in advance to understand whether the terminal supports the fast BWP handover function. Optionally, the base station notifies the terminal in some way to dynamically enable or disable the fast BWP handover function. For example, the base station sets the first timeslot offset to be less than the minimum BWP handover delay specified by the mobile communication protocol, or sets it to be equal to 0, thereby notifying the terminal to enable the fast BWP handover function, that is, requiring the terminal to receive PDSCH on the source BWP.

[0067] The minimum BWP handover latency specified in the mobile communication protocol is generally determined based on the UE capabilities and time slot length in 5G NR mobile communication systems, as shown in Table 1. Capability type 1 and capability type 2 in Table 1 are determined by the UE capabilities reported by the terminal to the base station.

[0068]

[0069] Table 1: Minimum BWP handover latency for 5G NR

[0070] As shown in Table 1, in a 5G NR mobile communication system, the minimum BWP handover latency will not be less than one time slot. Therefore, in a 5G NR mobile communication system, it is feasible to notify the terminal to enable the fast BWP handover function by setting the first time slot offset to 0.

[0071] If we denote the minimum first time slot offset simultaneously supported by the base station and the terminal as N0, the minimum second time slot offset simultaneously supported by the base station and the terminal as N1, and the minimum BWP handover delay as T... BWPswitchDelay Therefore, for the existing NR mobile communication protocol, the shortest interval from when the terminal receives the "downlink DCI indicating BWP handover" to when the terminal sends HARQ feedback to the base station is: D old =max(N0,T BWPswitchDelay )+N1, where the unit is the number of time slots. The max() function represents the maximum value.

[0072] If the fast BWP handover method proposed in this application is adopted, the shortest interval from when the terminal receives the "downlink DCI indicating BWP handover" to when the terminal sends HARQ feedback to the base station is: D new =N0+max(N1,T) BWPswitchDelay ).

[0073] Existing 5G NR terminals typically support N0=0, but require N1>0, in which case D new <D oldTherefore, in FDD scenarios, this application enables the terminal to send HARQ feedback to the base station earlier. In TDD scenarios, since the terminal's uplink transmission and downlink reception are constrained by the frame structure, this application enables the terminal to provide HARQ feedback earlier or with the same latency as existing 5G communication protocols.

[0074] While existing DCI-based BWP handover methods offer low handover latency, they suffer from insufficient reliability. Some existing solutions address reliability issues but introduce significant handover latency. The fast BWP handover method proposed in this application, also a DCI-based BWP handover method, not only solves the reliability problem but also achieves handover latency nearly equal to, and in some cases even faster than, that of the protocol. Furthermore, this application transmits the "downlink DCI indicating BWP handover" and the PDSCH scheduled by the "downlink DCI indicating BWP handover" sequentially on the source BWP. This allows the tasks of "BWP handover" and "data or signaling with higher priority that needs to be sent to the UE" to be executed in parallel, improving task parallelism.

[0075] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for rapidly switching BWPs in a mobile communication system, characterized in that, The process includes the following steps: The BWP before the switch is called the source BWP, and the BWP after the switch is called the target BWP. Step S1: The base station sends a downlink DCI indicating BWP handover and a PDSCH scheduled by the downlink DCI indicating BWP handover to the terminal on the source BWP; the downlink DCI indicating BWP handover records the target BWP information and the PDSCH scheduling information, and the PDSCH scheduling information is the PDSCH time domain and frequency domain resources allocated on the source BWP. Step S2: The terminal receives the downlink DCI indicating BWP handover on the source BWP, obtains the target BWP information and PDSCH scheduling information from it, and receives the PDSCH scheduled by the downlink DCI indicating BWP handover on the source BWP according to the PDSCH scheduling information, and decodes the received PDSCH. If the terminal successfully decodes the PDSCH, the terminal determines that the received downlink DCI indicating BWP switching is real, and the terminal immediately switches to the target BWP specified by the downlink DCI indicating BWP switching, and then proceeds to step S3. If the terminal fails to decode the PDSCH, the terminal determines that the received downlink DCI indicating BWP switching is a false detection, and the terminal continues to remain on the source BWP. Step S3: The terminal sends HARQ feedback to the base station on the target BWP; Step S4: The base station receives HARQ feedback on the target BWP and determines whether the terminal successfully switched BWPs.

2. The method for fast BWP switching in a mobile communication system according to claim 1, characterized in that, The downlink DCI indicating BWP switching includes any one of DCI format 1_1, DCI format 1_2, and DCI format 1_3.

3. A method for fast BWP handover on the base station side, characterized in that, Includes the following steps; Step S21: The base station schedules the downlink DCI indicating BWP handover on the source BWP, and the PDSCH of the downlink DCI indicating BWP handover is also scheduled by the base station on the source BWP. The downlink DCI indicating BWP handover is recorded with a first time slot offset, which is used to indicate how many time slots the base station has passed after sending the downlink DCI indicating BWP handover before sending the PDSCH scheduled by the downlink DCI indicating BWP handover. The downlink DCI that indicates BWP switching also records a second time slot offset, which is used to indicate how many time slots the terminal sends the corresponding HARQ feedback after receiving PDSCH data. Step S22: The base station sends a downlink DCI indicating BWP handover and its scheduled PDSCH to the terminal on the source BWP. The transmission interval of the two follows the first time slot offset. Whether the PDSCH is successfully decoded on the terminal side is used to determine whether the downlink DCI indicating BWP handover is a false detection and to decide whether to switch to the target BWP. Step S23: The base station receives the HARQ feedback sent by the terminal at the time when the terminal sends the HARQ feedback calculated based on the second time slot offset on the target BWP. If the base station receives HARQ feedback, it determines that the terminal's BWP handover was successful; if the base station does not receive HARQ information, it determines that the terminal's BWP handover failed.

4. The method for fast BWP handover on the base station side according to claim 3, characterized in that, The time-domain resource allocation field in the downlink DCI indicating BWP switching records the first time slot offset.

5. The method for fast BWP handover on the base station side according to claim 3, characterized in that, The PDSCH to HARQ feedback timing indication field in the downlink DCI indicating BWP switching records a second time slot offset.

6. A method for fast BWP handover on the terminal side, characterized in that, Includes the following steps; Step S31: The terminal receives a downlink DCI indicating BWP handover sent by the base station on the source BWP; the terminal parses the downlink DCI indicating BWP handover to obtain the first time slot offset and the second time slot offset. The first time slot offset is used to indicate how many time slots the base station needs to wait after sending the downlink DCI indicating BWP handover before sending the PDSCH scheduled by the downlink DCI indicating BWP handover; the second time slot offset is used to indicate how many time slots the terminal needs to wait after receiving the PDSCH data before sending the corresponding HARQ feedback. Step S32: The terminal receives the PDSCH sent by the base station on the source BWP at the time when the base station sends the PDSCH calculated based on the first timeslot offset; Step S33: The terminal decodes the received PDSCH; If the terminal successfully decodes the PDSCH, the terminal determines that the received downlink DCI indicating BWP switching is real, and the terminal immediately switches to the target downlink BWP specified by the downlink DCI indicating BWP switching, and then proceeds to step S34. If the terminal fails to decode the PDSCH, the terminal determines that the received downlink DCI indicating BWP switching is a false detection, and the terminal continues to remain on the source BWP. Step S34: After the terminal successfully switches BWP, it sends HARQ feedback to the base station on the target BWP at the time calculated based on the second time slot offset; whether the HARQ feedback is successfully received on the base station side is used to determine whether the terminal's BWP switching is successful.

7. The method for fast BWP switching on the terminal side according to claim 6, characterized in that, In step S33, when the terminal switches to the target downlink BWP, for asymmetric spectrum, the terminal simultaneously switches the uplink active BWP to the uplink BWP associated with the downlink target BWP; for symmetric spectrum, when the terminal selects a paired configuration of uplink and downlink BWPs, the terminal simultaneously switches the uplink active BWP to the uplink BWP with the same identification number as the downlink BWP.

8. A device for rapidly switching BWPs, characterized in that, It consists of a base station and a terminal; The base station is used to send a downlink DCI indicating BWP handover and a PDSCH scheduled by the downlink DCI to the terminal on the source BWP. The downlink DCI indicating BWP handover records information about the target BWP and scheduling information of the PDSCH. The scheduling information of the PDSCH is the time-domain and frequency-domain resources of the PDSCH allocated on the source BWP. The base station is also used to receive HARQ feedback on the target BWP to determine whether the terminal's BWP handover was successful. The terminal is used to receive the downlink DCI indicating BWP handover on the source BWP, obtain the target BWP information and PDSCH scheduling information from it, and receive the PDSCH scheduled by the downlink DCI indicating BWP handover on the source BWP according to the PDSCH scheduling information, and decode the received PDSCH. If the terminal successfully decodes the PDSCH, the terminal determines that the received downlink DCI indicating BWP switching is real, and the terminal immediately switches to the target BWP specified by the downlink DCI indicating BWP switching. After the terminal successfully switches to the target BWP, the terminal sends HARQ feedback to the base station from the target BWP. If the terminal fails to decode the PDSCH, the terminal determines that the received downlink DCI indicating BWP switching is a false detection, and the terminal continues to remain on the source BWP.

9. A base station for fast BWP handover, characterized in that, It includes a scheduling unit, a sending unit, and a receiving and judgment unit; The scheduling unit is used to schedule the downlink DCI indicating BWP handover onto the source BWP; the PDSCH of the downlink DCI indicating BWP handover is also scheduled onto the source BWP by the scheduling unit. The sending unit is used to send a downlink DCI indicating BWP switching and its scheduled PDSCH to the terminal on the source BWP; whether the PDSCH is successfully decoded on the terminal side is used to determine whether the downlink DCI indicating BWP switching is a false detection and to decide whether to switch to the target BWP. The receiving and judging unit is used to receive HARQ feedback sent by the terminal on the target BWP; if HARQ feedback is received, the receiving and judging unit determines that the terminal has successfully switched BWPs; if no HARQ feedback is received, the receiving and judging unit determines that the terminal has failed to switch BWPs.

10. A terminal for quickly switching BWPs, characterized in that, It includes a receiving unit, a decoding unit, a BWP switching unit, and a HARQ feedback unit; The receiving unit is used to receive a downlink DCI indicating BWP handover sent by the base station on the source BWP, and is also used to receive a PDSCH scheduled by the downlink DCI indicating BWP handover sent by the base station on the source BWP. The decoding unit is used to decode the received PDSCH; The BWP switching unit is used to immediately switch to the target BWP specified by the downlink DCI that indicates the BWP switching when the PDSCH decoding is successful; it is also used to remain on the source BWP when the PDSCH decoding fails. The HARQ feedback unit is used to send HARQ feedback to the base station on the target BWP after a successful BWP handover; whether the HARQ feedback is successfully received on the base station side is used to determine whether the terminal's BWP handover was successful.

Images