A method, user equipment and system for low power time and frequency offset synchronization

Abstract

The application provides a low-power time-frequency offset synchronization method, user equipment and system. A physical downlink control channel is monitored in a preset time window to obtain a monitoring signal. The preset time window contains a monitoring time of the physical downlink control channel when receiving a paging early indication sent by a network device. Time-frequency offset pre-synchronization is performed according to the monitoring signal. By using the received paging early indication to track the time-frequency offset, the SSB is not used for time-frequency offset synchronization, and the power consumption of the user equipment is further reduced.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a low-power time-frequency offset synchronization method, user equipment, and system. Background Technology

[0002] When user equipment (UE) using NR (New Radio) technology enters deep sleep mode during standby, the 32K crystal timing device used has a relatively large error, which can introduce significant time-frequency offset issues. Therefore, in existing technologies, the UE needs to use the downlink signal continuously transmitted by the NR base station to perform time-frequency offset pre-synchronization using an SSB (Synchronization Signal Block), which we call Pre-Sync. (Reference) Figure 1 The CD SSB (cell defining SSB) period is typically 20ms, which results in an unpredictable (1-20ms) and relatively long interval between the SSB and the paging occupancy (PO). During this time interval, the UE cannot enter deep sleep mode; furthermore, the overhead of using the SSB for time-frequency offset pre-synchronization increases standby power consumption. Additionally, each time a PO is received, an extra SSB needs to be received, increasing software scheduling complexity as the software needs to calculate the relative time between the SSB and PO. Therefore, both SSB interface demodulation and the time interval between the SSB and PO increase UE standby power consumption. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a low-power time-frequency offset synchronization method, user equipment, and system, aiming to solve the technical problem of how to further reduce the power consumption of user equipment in the prior art.

[0004] A low-power time-frequency offset synchronization method includes:

[0005] Step A1: Monitor the physical downlink control channel within a preset time window to obtain a monitoring signal. The preset time window includes the timing of monitoring the physical downlink control channel when receiving an early paging indication sent by the network device.

[0006] Step A2: Perform time-frequency offset pre-synchronization based on the monitoring signal.

[0007] Furthermore, in step A1, the starting position of the preset time window is preceded by a first preset number of symbols by the starting position of the monitoring timing.

[0008] Furthermore, in step A1, the end position of the preset time window is delayed by a second preset number of symbols compared to the end position of the monitoring timing.

[0009] Furthermore, step A2 includes:

[0010] Step A21: Obtain initial calibration data, which includes time offset and frequency offset values;

[0011] Step A22: Decode the monitoring signal based on the calibration data to obtain the decoding result;

[0012] Step A23: Determine whether the early paging indication was successfully decoded based on the decoding result.

[0013] If not, proceed to step A24;

[0014] If so, proceed to step A25;

[0015] Step A24: Adjust the calibration data and continue with step A22 using the adjusted calibration data;

[0016] Step A25 outputs the calibration data used for decoding when the paging early indication is successfully decoded.

[0017] A low-power time-frequency offset synchronization user equipment, comprising the aforementioned low-power time-frequency offset synchronization method, including:

[0018] The monitoring module is used to monitor the physical downlink control channel within a preset time window to obtain monitoring signals. The preset time window includes the timing of monitoring the physical downlink control channel when receiving indication messages sent by network devices.

[0019] The execution module, connected to the monitoring module, is used for time-frequency offset pre-synchronization based on the monitoring signal.

[0020] Furthermore, the starting position of the preset time window is a first preset number of symbols earlier than the starting position of the monitoring timing.

[0021] Furthermore, the end position of the preset time window is delayed by a second preset number of symbols compared to the end position of the monitoring timing.

[0022] Furthermore, the execution module includes:

[0023] The initial setup unit is used to set the initial calibration data, which includes time offset and frequency offset values.

[0024] The decoding unit, connected to the initial setting unit, is used to decode the monitoring signal based on the calibration data to obtain the decoding result;

[0025] The judgment unit, connected to the decoding unit, is used to determine whether the early paging indication has been successfully decoded based on the decoding result, and outputs the judgment result.

[0026] The adjustment unit, connected to the judgment unit, is used to adjust the calibration data when the judgment result is that the early paging indication was not successfully decoded.

[0027] The decoding unit is also connected to the adjustment unit, which is used to decode the monitoring signal using the adjusted calibration data to obtain the decoding result;

[0028] The output unit, connected to the judgment unit, is used to output the calibration data used for decoding when the paging early indication was successfully decoded if the judgment result is that the early indication was not successfully decoded.

[0029] A low-power time-frequency offset synchronization system, using the aforementioned low-power time-frequency offset synchronization method, includes:

[0030] Network devices are used to send data to user equipment;

[0031] User equipment, used for:

[0032] The physical downlink control channel is monitored within a preset time window to obtain monitoring signals. The preset time window includes the timing of monitoring the physical downlink control channel when receiving signals from network devices.

[0033] Time-frequency offset pre-synchronization is performed based on monitoring signals.

[0034] Furthermore, the starting position of the preset time window is a first preset number of symbols earlier than the starting position of the monitoring timing.

[0035] The beneficial technical effect of the present invention is that by using the received paging early indication for time-frequency offset tracking, without using SSB for time-frequency offset synchronization, the power consumption of user equipment is further reduced. Attached Figure Description

[0036] Figure 1 A timing diagram illustrating the pre-synchronization of SSB reception in existing technologies;

[0037] Figure 2 This is a timing diagram illustrating the low-power time-frequency offset synchronization method of the present invention for receiving PEI for time-frequency offset pre-synchronization;

[0038] Figure 3 , 5 This is a flowchart illustrating the steps of a low-power time-frequency offset synchronization method of the present invention for receiving PEI and performing time-frequency offset pre-synchronization.

[0039] Figure 4 A schematic diagram illustrating the timing for setting a preset time window in a low-power time-frequency offset synchronization method according to the present invention;

[0040] Figure 6-7 This is a schematic diagram of a user equipment and system with low power consumption time-frequency offset synchronization according to the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0044] See Figure 3 This invention provides a low-power time-frequency offset synchronization method, comprising:

[0045] Step A1: Monitor the Physical Downlink Control Channel (PDCCH) within a preset time window to obtain monitoring signals. The preset time window includes receiving Early Paging Indication (PEI) sent by the network device.

[0046] The timing for monitoring the physical downlink control channel;

[0047] Step A2: Perform time-frequency offset pre-synchronization based on the monitoring signal.

[0048] See Figure 2In this invention, an Early Paging Indication (PEI) is introduced. This PEI is sent to the User Equipment (UE) by the network device before the Paging Occurrence (PO). The UE only monitors the PO if the PEI notifies it that monitoring is required. If the UE is notified that monitoring is unnecessary, it will skip monitoring when the PO arrives, and the UE will then monitor the PO. The PEI and SSB share the same characteristics: the network device continuously sends the PEI to the UE at fixed intervals, even if no paging schedule is initiated. Therefore, in this invention, the PEI not only indicates whether monitoring of the PO is required but can also be used for AGC (Automatic Gain Control), AFC (Automatic Frequency Control), and ATC (Automatic Time Control) loop tracking. This eliminates the need for additional SSB scheduling and time-frequency offset pre-synchronization, simplifying software design and reducing device power consumption.

[0049] Furthermore, in step A1, the starting position of the preset time window is preceded by a first preset number of symbols by the starting position of the monitoring timing.

[0050] Specifically, the initial preset quantity is 4. A time slot typically has 14 symbols. The physical downlink control channel can be monitored 4 symbols in advance.

[0051] Furthermore, in step A1, the end position of the preset time window is delayed by a second preset number of symbols compared to the end position of the monitoring timing.

[0052] Specifically, the second preset quantity is 4, which allows for monitoring of the physical downlink control channel with a delay of 4 symbols.

[0053] See Figure 5 Furthermore, step A2 includes:

[0054] Step A21: Obtain initial calibration data, which includes time offset and frequency offset values;

[0055] Step A22: Decode the monitoring signal based on the calibration data to obtain the decoding result;

[0056] Step A23: Determine whether the early paging indication was successfully decoded based on the decoding result.

[0057] If not, proceed to step A24;

[0058] If so, proceed to step A25;

[0059] Step A24: Adjust the calibration data and continue with step A22 using the adjusted calibration data;

[0060] Step A25 outputs the calibration data used for decoding when the paging early indication is successfully decoded.

[0061] Typically, during time-frequency offset pre-synchronization, multiple time and frequency offset values ​​are used. Different time and frequency offset values ​​are used to calibrate the monitoring signal. The multiple time offset values ​​form a first numerical sequence, and the multiple frequency offset values ​​form a second numerical sequence. In step A24, when adjusting the calibration data, the currently used frequency offset value is first fixed. The time offset values ​​in the first numerical sequence are used sequentially to construct new calibration data as the adjusted calibration data. When the time offset values ​​in the first numerical sequence are traversed, the untraversed frequency offset values ​​are selected from the second numerical sequence and combined with the time offset values ​​in the first numerical sequence as the adjusted time offset values. The frequency offset pre-synchronization process ends only when PEI decoding is successful.

[0062] When the network needs to send downlink data to a UE that is idle or inactive, the network must first page the UE through a paging process to notify the UE to establish or restore an RRC connection before data transmission can proceed. Idle or inactive UEs support using discontinuous reception (DRX) to receive paging messages to reduce power consumption. This DRX is also known as paging DRX. The discontinuous reception cycle (DRX cycle) is configured by the network device. Using DRX, idle or inactive UEs will only "wake up" to receive paging messages during a predefined time period, and can remain in a "sleep" state and stop receiving paging messages at other times.

[0063] See Figure 4 In step A1, within a discontinuous reception cycle (DRX cycle), after the user equipment wakes up from sleep mode, a preset time window is set before the PEI monitoring opportunity arrives. Specifically, the user equipment sets the preset time window relative to at least the time slot preceding the time slot where the monitoring opportunity occurs.

[0064] In this invention, the monitoring signal includes two signals, I and Q. An NCO (numerically controlled oscillator) is used to perform phase rotation on the sampled signals in the monitoring signal. Each phase rotation corresponds to a different frequency offset value. The relevant formula is as follows:

[0065] y(n)=r(n)e -j2πnΔf / fs =r(n)e jθ(n) ;

[0066] in,

[0067] r(n) represents the nth sampled signal in the monitoring signal;

[0068] y(n) represents the sampled signal after phase rotation;

[0069] Δf represents the frequency offset;

[0070] fs represents the sampling frequency;

[0071] θ(n) represents the phase of the nth sampled signal.

[0072] See Figure 6 The present invention also provides a low-power time-frequency offset synchronization user equipment, comprising the aforementioned low-power time-frequency offset synchronization method, including:

[0073] The monitoring module (11) is used to monitor the physical downlink control channel within a preset time window to obtain a monitoring signal. The preset time window includes the timing of monitoring the physical downlink control channel when receiving an indication message sent by the network device.

[0074] The execution module (12) is connected to the monitoring module (11) and is used to perform time-frequency offset pre-synchronization based on the monitoring signal.

[0075] PEI and SSB share the same characteristics: network devices continuously send PEI signals to user equipment at fixed intervals, even without paging or scheduling the user equipment. Therefore, in this invention, the Early Paging Indicator (PEI) not only indicates whether PO (Position Request) monitoring is needed, but can also be used for AGC (Automatic Gain Control), AFC (Automatic Frequency Control), and ATC (Automatic Time Control) loop tracking. This eliminates the need for additional SSB scheduling and time-frequency offset pre-synchronization using SSB, simplifying software design and reducing device power consumption.

[0076] Furthermore, the starting position of the preset time window is a first preset number of symbols earlier than the starting position of the monitoring timing.

[0077] Furthermore, the end position of the preset time window is delayed by a second preset number of symbols compared to the end position of the monitoring timing.

[0078] See Figure 7 Furthermore, the execution module (12) includes:

[0079] The initial setting unit (121) is used to set the initial calibration data, which includes time offset and frequency offset values;

[0080] The decoding unit (122) is connected to the initial setting unit (121) and is used to decode the monitoring signal according to the calibration data to obtain the decoding result;

[0081] The judgment unit (123) is connected to the decoding unit (122) and is used to determine whether the paging early indication has been successfully decoded based on the decoding result, and output the judgment result.

[0082] The adjustment unit (124) is connected to the judgment unit (123) and is used to adjust the calibration data when the judgment result is that the early paging indication was not successfully decoded.

[0083] The decoding unit (122) is also connected to the adjustment unit (124) for decoding the monitoring signal using the adjusted calibration data to obtain the decoding result;

[0084] The output unit (125) is connected to the judgment unit (123) and is used to output the calibration data used for decoding when the paging early indication is successfully decoded when the judgment result is that the paging early indication was not successfully decoded.

[0085] The present invention also provides a low-power time-frequency offset synchronization system, using the aforementioned low-power time-frequency offset synchronization method, comprising:

[0086] Network device (2) is used to send an early paging indication to user equipment (1);

[0087] User equipment (1), used for:

[0088] The physical downlink control channel is monitored within a preset time window to obtain monitoring signals. The preset time window includes the timing of monitoring the physical downlink control channel when receiving paging early indications sent by network devices.

[0089] Time-frequency offset pre-synchronization is performed based on monitoring signals.

[0090] PEI and SSB share the same characteristics: network devices continuously send PEI signals to user equipment at fixed intervals, even without paging or scheduling the user equipment. Therefore, in this invention, the Early Paging Indicator (PEI) not only indicates whether PO (Position Request) monitoring is needed, but can also be used for AGC (Automatic Gain Control), AFC (Automatic Frequency Control), and ATC (Automatic Time Control) loop tracking. This eliminates the need for additional SSB scheduling and time-frequency offset pre-synchronization using SSB, simplifying software design and reducing device power consumption.

[0091] Furthermore, the starting position of the preset time window is a first preset number of symbols earlier than the starting position of the monitoring timing.

[0092] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-power time-frequency offset synchronization method, characterized in that, include: Step A1: Monitor the physical downlink control channel within a preset time window to obtain a monitoring signal. The preset time window includes the timing of monitoring the physical downlink control channel when receiving an early paging indication sent by a network device. Step A2: Perform time-frequency offset pre-synchronization based on the monitoring signal; Step A2 includes: Step A21: Obtain initial calibration data, which includes time offset and frequency offset values; Step A22: Decode the monitoring signal based on the calibration data to obtain the decoding result; Step A23: Determine whether the paging early indication was successfully decoded based on the decoding result. If not, proceed to step A24; If so, proceed to step A25; Step A24: Adjust the calibration data and continue performing step A22 using the adjusted calibration data; Step A25: Output the calibration data used for decoding when the paging early indication is successfully decoded.

2. The low-power time-frequency offset synchronization method as described in claim 1, characterized in that, In step A1, the starting position of the preset time window is a first preset number of symbols earlier than the starting position of the monitoring timing.

3. The low-power time-frequency offset synchronization method as described in claim 2, characterized in that, In step A1, the end position of the preset time window is delayed by a second preset number of symbols compared to the end position of the monitoring timing.

4. A low-power time-frequency offset synchronization user equipment, characterized in that, include: The monitoring module is used to monitor the physical downlink control channel within a preset time window to obtain monitoring signals. The preset time window includes the timing of monitoring the physical downlink control channel when receiving an early paging indication sent by a network device. The execution module, connected to the monitoring module, is used to perform time-frequency offset pre-synchronization based on the monitoring signal; The execution module includes: An initial setup unit is used to set initial calibration data, which includes time offset and frequency offset values. A decoding unit, connected to the initial setting unit, is used to decode the monitoring signal according to the calibration data to obtain a decoding result; The judgment unit, connected to the decoding unit, is used to determine whether the paging early indication has been successfully decoded based on the decoding result, and output the judgment result; An adjustment unit, connected to the judgment unit, is used to adjust the calibration data when the judgment result indicates that the paging early indication was not successfully decoded. The decoding unit is also connected to the adjustment unit, and is used to decode the monitoring signal using the adjusted calibration data to obtain a decoding result; An output unit, connected to the judgment unit, is used to output the calibration data used for decoding when the judgment result is that the paging early indication has been successfully decoded.

5. A low-power time-frequency offset synchronization user equipment as described in claim 4, characterized in that, The starting position of the preset time window is a first preset number of symbols earlier than the starting position of the monitoring timing.

6. A low-power time-frequency offset synchronization user equipment as described in claim 5, characterized in that, The end position of the preset time window is delayed by a second preset number of symbols compared to the end position of the monitoring timing.

7. A low-power time-frequency offset synchronization system, characterized in that, include: Network equipment used to send early paging instructions to user equipment; User equipment, used for: The physical downlink control channel is monitored within a preset time window to obtain a monitoring signal. The preset time window includes the timing of monitoring the physical downlink control channel when the paging early indication sent by the network device is received. Based on the monitoring signal, time-frequency offset pre-synchronization is performed, including: Set initial calibration data, which includes time offset and frequency offset values; The monitoring signal is decoded based on the calibration data to obtain the decoding result; Based on the decoding result, determine whether the paging early indication was successfully decoded, and output the determination result; When the judgment result is that the paging early indication was not successfully decoded, the calibration data is adjusted, and the adjusted calibration data is used to decode the monitoring signal to obtain the decoding result. When the determination result is that the paging early indication is successfully decoded, the calibration data used for decoding when the paging early indication is successfully decoded is output.

8. The low-power time-frequency offset synchronization system as described in claim 7, characterized in that, The starting position of the preset time window is a first preset number of symbols earlier than the starting position of the monitoring timing.

Images