Electronic device and method applied to electronic device supporting narrowband internet of things

Abstract

The invention discloses an electronic device and a method applied to the electronic device supporting the narrowband Internet of Things. The method comprises the following steps: selecting a cost function; simulating a first probability density function of the cost function on a target center frequency point, a second probability density function of the cost function on a first adjacent center frequency point of the target center frequency point, and a third probability density function of the cost function on a second adjacent center frequency point of the target center frequency point; and a fourth probability density function of the cost function on a pure noise center frequency point; and calculating the probability that the electronic device successfully detects the target center frequency point of an information frame from a base station according to the first, second, third and fourth probability density functions.

Description

Technical Field

[0001] This invention relates to wireless communication systems. Background Technology

[0002] In the early stages of product design, simulation and evaluation are typically used to predict product performance, providing a reference for subsequent product implementation. However, for some products, the workload of simulation and evaluation is extremely large, causing difficulties for designers. Taking Narrow-Band Internet of Things (NB-IoT) as an example, the frequency scanning operation of its system requires scanning thousands of center frequency points, making simulation and evaluation quite time-consuming. Therefore, developing an efficient simulation and evaluation method is an important issue. Summary of the Invention

[0003] Therefore, one of the objectives of this invention is to provide a method for electronic devices supporting narrowband Internet of Things (IoT) that can efficiently predict the system's performance across multiple center frequency points, thereby addressing the problems described in the prior art.

[0004] In one embodiment of the present invention, a method for applying to an electronic device supporting narrowband Internet of Things is disclosed, comprising the following steps: selecting a cost function; simulating a first probability density function of the cost function at a target center frequency, a second probability density function of the cost function at a first adjacent center frequency of the target center frequency, a third probability density function of the cost function at a second adjacent center frequency of the target center frequency, and a fourth probability density function of the cost function at a pure noise center frequency, wherein the target center frequency is used to represent a center frequency of an information frame transmitted by a base station; and calculating the probability that the electronic device successfully detects the target center frequency of the information frame from the base station through frequency scanning based on the first probability density function, the second probability density function, the third probability density function, and the fourth probability density function.

[0005] In one embodiment of the present invention, an electronic device is disclosed, which is configured to perform the following operations: selecting a cost function; simulating a first probability density function of the cost function at a target center frequency, a second probability density function of the cost function at a first adjacent center frequency of the target center frequency, a third probability density function of the cost function at a second adjacent center frequency of the target center frequency, and a fourth probability density function of the cost function at a pure noise center frequency, wherein the target center frequency is used to represent a center frequency of an information frame transmitted by a base station; and calculating the probability that the electronic device successfully detects the target center frequency of the information frame from the base station through frequency scanning based on the first probability density function, the second probability density function, the third probability density function, and the fourth probability density function. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of an electronic device according to an embodiment of the present invention.

[0007] Figure 2 A flowchart illustrating a method for determining the probability that an electronic device successfully detects a target center frequency point from an information frame from a base station, according to an embodiment of the present invention.

[0008] Symbol Explanation

[0009] 100: Electronic devices

[0010] 110: Transceiver circuit

[0011] 120: Calculation Circuit

[0012] 130: Storage unit

[0013] 200-206: Steps Detailed Implementation

[0014] Figure 1 This is a schematic diagram of an electronic device 100 according to an embodiment of the present invention, wherein the electronic device 100 is a user terminal device supporting narrowband Internet of Things (NB-IoT). Figure 1 As shown, the electronic device 100 includes a transceiver circuit 110, a computing circuit 120, and a storage unit 130. In operation of the electronic device 100, the transceiver circuit 110 includes a wireless communication function for communicating wirelessly with a base station (cell); and the computing circuit 120 may be a circuit or electronic component with program execution capability, such as a central processing unit, microprocessor, or microprocessor unit, which executes the functions of the electronic device 100 by executing program code or program instructions in the storage unit 130.

[0015] During the connection process between electronic device 100 and base station, computing circuit 120 receives at least one information frame from base station via transceiver circuit 110 and synchronizes with base station based on a narrowband primary synchronization signal (NPSS) and a narrowband secondary synchronization signal (NSSS) in the information frame. Details of the synchronization between electronic device 100 and base station are well known to those skilled in the art; for example, reference can be made to U.S. Patent Application US10,455,485, therefore, such details will not be elaborated here.

[0016] Furthermore, during the connection process between the electronic device 100 and the base station, the electronic device 100 first performs a frequency scan to determine the target center frequency of the information frame transmitted by the base station before proceeding with subsequent operations. For example, not limited by this invention, the information frame transmitted by the base station may contain 12 subcarriers with a carrier spacing of 15 kilo-Hertz (kHz), a signal bandwidth of 180 kHz, and an interval of 100 kHz between adjacent center frequencies. The electronic device 100 needs to perform 1950 center frequency scans to determine the target center frequency of the information frame transmitted by the base station. Furthermore, the electronic device 100 has a cost function. During frequency scanning, the calculation circuit 120 uses the cost function to calculate the signal at each center frequency point to obtain a calculation result. Since the cost function is designed based on the characteristics of the narrow-band master synchronization signal in the information frame, and the calculation result of the cost function can reflect the energy of the scanned center frequency point, the calculation result generated when scanning the target center frequency point will be significantly different from the calculation result when scanning a non-target center frequency point. For example, the calculation result generated when scanning the target center frequency point will have a higher value. Therefore, the calculation circuit 120 can determine the target center frequency point of the information frame transmitted by the base station based on the calculation result corresponding to each center frequency point. Furthermore, since the aforementioned frequency sweeping operation and the design and operation of the cost function are well known to those skilled in the art, for example, reference can be made to US patent application US10,455,485 and the “NB-PSS and NB-SSS Design” proposed by Qualcomm Incorporated at the 2016 3rd Generation Partnership Project (3GPP) meeting, the relevant details will not be elaborated here.

[0017] However, although theoretically the calculation results when scanning the target center frequency will differ significantly from those when scanning a non-target center frequency, under the influence of many non-ideal factors, the actual calculation results when scanning the target center frequency may not necessarily have the highest value (scanning the target center frequency is a probabilistic event). Therefore, the present invention proposes the following embodiments to efficiently predict the performance of the electronic device 100 after scanning multiple center frequencies, that is, to predict the probability that the electronic device 100 can distinguish the target center frequency through the calculation results corresponding to each center frequency, for the design of the operation of the electronic device 100.

[0018] Figure 2 A flowchart illustrating a method for determining the probability that an electronic device 100 successfully detects a target center frequency point from an information frame from a base station, according to an embodiment of the present invention, wherein... Figure 2 The process can be executed by the electronic device 100 itself, or by other electronic devices. At step 200, the process begins. At step 202, a cost function is selected, for example, referring to Qualcomm's "NB-PSS and NB-SSSDesign". At step 204, the probability density function (PDF) of the cost function at a target center frequency is simulated (or statistically analyzed), the probability density function of the cost function at a first adjacent center frequency of the target center frequency (e.g., the center frequency corresponding to the target center frequency minus 100kHz), the probability density function of the cost function at a second adjacent center frequency of the target center frequency (e.g., the center frequency corresponding to the target center frequency plus 100kHz), and the probability density function of the cost function at a pure noise center frequency far from the target center frequency, wherein the target center frequency is used to represent the center frequency of the information frame transmitted by the base station. The pure noise center frequency can be a certain frequency higher than the target center frequency, for example, 500 kHz, so that other center frequencies will not be interfered with by signals at the target center frequency, and the signals thereon can be considered pure noise. In one embodiment, the probability density function described above can be generated by simulating or calculating the probability distribution of the cost function at the target center frequency, the first adjacent center frequency, the second adjacent center frequency, and the pure noise center frequency multiple times (e.g., 5000 times), wherein some values ​​in the probability density function can be smoothed using interpolation. Furthermore, in one embodiment, the probability density function described above describes the probability density distribution of the cost function values ​​within a frequency range.

[0019] In step 206, the probability that the electronic device 100 successfully detects the target center frequency of the information frame from the base station through frequency scanning is calculated based on the four probability density functions determined in step 204. In this embodiment, the frequency scanning strategy of the electronic device 100 using a cost function to perform frequency scanning can be used to determine how to calculate the probability of the electronic device 100 successfully detecting the target center frequency of the information frame from the base station based on the four probability density functions. The frequency scanning strategy can be a time-division frequency scanning strategy or a non-time-division frequency scanning strategy.

[0020] If the electronic device 100 adopts a time-division multiplexing frequency strategy, it can perform multiple rounds (e.g., three rounds) of scanning. Each round of scanning only scans a portion of the center frequencies of multiple center frequencies and uses a cost function to calculate the result for each center frequency. Then, it calculates the probability of determining the target center frequency in these three rounds of scanning. Specifically, assuming the electronic device 100 needs to scan a total of 1950 center frequencies, the difference between adjacent center frequencies is 100kHz, and the electronic device 100 performs three rounds of scanning, then each round needs to scan 650 center frequencies, and the difference between adjacent center frequencies in each round is 300kHz. For example, assuming that the lower the center frequency number, the lower the frequency, in the first round of scanning, the electronic device scans the 2nd, 5th, 8th, 11th, ..., 1949th center frequencies; in the second round of scanning, the electronic device scans the 1st, 4th, 7th, 10th, ..., 1948th center frequencies; and in the third round of scanning, the electronic device scans the 3rd, 6th, 9th, 12th, ..., 1950th center frequencies. In predicting the detection probability of the target center frequency, it is assumed that the probability density function of the target center frequency band is f0(x), and the probability density function of the first adjacent center frequency of the target center frequency (e.g., the center frequency corresponding to the target center frequency minus 100kHz) is f... -1 (x) The probability density function of the second adjacent center frequency of the target center frequency (e.g., the center frequency corresponding to the target center frequency plus 100kHz) is f. +1 (x), the probability density function of the center frequency of pure noise is f n (x). In the first round of scanning, the probability P0 that the calculated cost function of the target center frequency containing the signal is greater than the calculated cost functions of all other center frequencies can be calculated using the following formula (1):

[0021]

[0022] In the second round of scanning, the probability P that the calculated cost function of the first adjacent center frequency of the target center frequency is greater than the calculated cost function of all other center frequency frequencies is... -1 The following formula (2) can be used to calculate:

[0023]

[0024] In the third round of scanning, the probability P that the calculated cost function of the second adjacent center frequency of the target center frequency is greater than the calculated cost functions of all other center frequency frequencies is... +1 The following formula (3) can be used to calculate:

[0025]

[0026] Where N is the number of center frequency points to be scanned in each round of scanning, and in this embodiment N is "650". In this embodiment, since the signal bandwidth is 180kHz and the interval between adjacent center frequency points is 100kHz, the information frame transmitted by the base station will appear in the range of at most three center frequency points. That is, if the information frame transmitted by the base station corresponds to the target center frequency point, the first adjacent center frequency point and / or the second adjacent center frequency point of the target center frequency point may be detected as having an information frame. Therefore, as long as any one of the target center frequency point, the first adjacent center frequency point, and the second adjacent center frequency point is detected by the electronic device 100 as having a signal, it can be considered as a successful frequency scan. Therefore, in the above three rounds of scanning, the following formula (4) can be used to calculate the probability P0 and probability P1 respectively according to the above formulas (1), (2), and (3). -1 Probability P +1 To calculate the probability P that electronic device 100 successfully detects the target center frequency point from the base station's information frame: P = 1 - (1 - P0)(1 - P -1 (1-P) +1 )………………………………(4).

[0027] If the electronic device 100 does not adopt a time-division frequency scanning strategy, the electronic device 100 will only perform one round of scanning, that is, scan 1950 center frequency points at a time. At this time, since the strength of the signals (e.g., narrow-band master synchronization signals) at the target center frequency point, the first adjacent center frequency point, and the second adjacent center frequency point are correlated to a certain extent, the cost functions of the target center frequency point, the first adjacent center frequency point, and the second adjacent center frequency point will not be completely independent. Therefore, the probability P of scanning out the signal can be calculated using the following formulas (5) to (8):

[0028]

[0029] P det =1-(1-P) 0-Full (1-P) +1-Full (1-P) -1-Full (8)

[0030] Where x is mentioned above T0 x T-1 x T-2 These represent the changes in the cost function of the target center frequency, the first adjacent center frequency, and the second adjacent center frequency, respectively.

[0031] In the above embodiments, it is only necessary to determine the probability density function of the cost function at the target center frequency, the first adjacent center frequency, the second adjacent center frequency, and the pure noise center frequency to accurately estimate the probability that the electronic device 100 can successfully sweep the frequency (that is, the calculated result of the cost function of any one of the target center frequency, the first adjacent center frequency, and the second adjacent center frequency is greater than the calculated result of the cost function of all other center frequencies). This avoids the problem in the prior art that it is necessary to calculate the cost function for all 1950 center frequencies, which makes the simulation and evaluation work quite time-consuming.

[0032] After simulating (or evaluating) the probability that electronic device 100 can successfully sweep frequencies, the method by which electronic device 100 scans a center frequency is controlled based on the calculated probability that electronic device 100 successfully detects the target center frequency from the base station's information frame. For example, the designer can use this information to decide whether to choose other cost functions or other frequency sweeping methods. For instance, if the probability that electronic device 100 can successfully sweep frequencies is lower than a critical value after simulation or evaluation, electronic device 100 can first select the M center frequencies with the highest calculated values ​​of the cost function during the frequency sweeping process, and then focus on scanning these M center frequencies again, selecting the center frequency with the highest calculated value of the cost function as the target center frequency, where M is a positive integer greater than or equal to 2.

[0033] Furthermore, in formula (1) above, the probability that the calculated result of the cost function of the target center frequency is greater than the calculated results of the cost functions of all other center frequencies is used. In other embodiments, the following formula (9) can also be used to calculate the probability that the calculated result of the cost function of the target center frequency is greater than the calculated results of the cost functions of other (NM) center frequencies (that is, the calculated result of the cost function of the target center frequency is ranked in the first M positions):

[0034]

[0035] As for the probability that the calculated result of the cost function of the first adjacent center frequency point is greater than the calculated result of the cost function of other (NM) center frequency points, and the probability that the calculated result of the cost function of the second adjacent center frequency point is greater than the calculated result of the cost function of other (NM) center frequency points, the formula (9) can be modified accordingly.

[0036] It should be noted that in the above embodiments, the description assumes that the electronic device 100 needs to scan 1950 center frequency points, and the frequency difference between two adjacent center frequency points is 100kHz. However, this feature is not a limitation of the present invention. In other embodiments, as long as the number of center frequency points that the electronic device 100 needs to scan is 3*N, the number of center frequency points that the electronic device 100 needs to scan in the first, second, and third scans are each N, and the center frequency points that the electronic device 100 needs to scan in the first, second, and third scans do not overlap; and the frequency difference between two adjacent center frequency points is A, and the frequency difference between two adjacent center frequency points that the electronic device 100 needs to scan in the first, second, and third scans is 3*A, where N can be any suitable positive integer, for example, N is 650, and A is 100kHz, the related design variations should fall within the scope of the present invention.

[0037] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention should be included within the scope of the present invention.

Claims

1. A method for use in an electronic device supporting narrowband Internet of Things, comprising: Choose a cost function; Simulate a first probability density function of the cost function at a target center frequency, a second probability density function of the cost function at a first adjacent center frequency of the target center frequency, a third probability density function of the cost function at a second adjacent center frequency of the target center frequency, and a fourth probability density function of the cost function at a pure noise center frequency, wherein the target center frequency is used to represent a center frequency of an information frame transmitted by a base station; and The probability that the electronic device successfully detects the target center frequency of the information frame from the base station through frequency scanning is calculated based on the first probability density function, the second probability density function, the third probability density function, and the fourth probability density function.

2. The method of claim 1, wherein the step of calculating the probability that the electronic device successfully detects the target center frequency of the information frame from the base station through the frequency scan based on the first probability density function, the second probability density function, the third probability density function, and the fourth probability density function comprises: Based on the first probability density function and the fourth probability density function, a first probability is calculated that the calculation result of the cost function for the target center frequency point is greater than the calculation result of the cost function for other center frequencies in a first round of scanning of the electronic device. Based on the second probability density function and the fourth probability density function, a second probability is calculated that the calculation result of the cost function for the first adjacent center frequency point is greater than the calculation result of the cost function for other center frequency points in a second round of scanning of the electronic device. Based on the third probability density function and the fourth probability density function, a third probability is calculated that, in a third scan of the electronic device, the calculation result of the cost function at the second adjacent center frequency point is greater than the calculation result of the cost function at other center frequencies; and The probability that the electronic device successfully detects the target center frequency of the information frame from the base station is calculated based on the first probability, the second probability, and the third probability.

3. The method as described in claim 2, wherein the number of multiple center frequency points to be scanned by the electronic device is 3*N, the number of center frequency points to be scanned in the first scan, the second scan, and the third scan of the electronic device are respectively N, and the center frequency points to be scanned in the first scan, the second scan, and the third scan of the electronic device will not repeat; and the frequency difference between two adjacent center frequency points of the multiple center frequency points is A, and the frequency difference between two adjacent center frequency points of the center frequency points to be scanned in the first scan, the second scan, and the third scan of the electronic device is 3*A.

4. The method of claim 3, wherein N is 650 and A is 100 kHz.

5. The method of claim 1, further comprising: Based on the calculated probability that the electronic device successfully detects the target center frequency point of the information frame from the base station, the method by which the electronic device scans the center frequency point is controlled.

6. An electronic device for performing the following operations: Choose a cost function; Simulate a first probability density function of the cost function at a target center frequency, a second probability density function of the cost function at a first adjacent center frequency of the target center frequency, a third probability density function of the cost function at a second adjacent center frequency of the target center frequency, and a fourth probability density function of the cost function at a pure noise center frequency, wherein the target center frequency is used to represent a center frequency of an information frame transmitted by a base station; and The probability that the electronic device successfully detects the target center frequency of the information frame from the base station through frequency scanning is calculated based on the first probability density function, the second probability density function, the third probability density function, and the fourth probability density function.

7. The electronic device of claim 6, wherein the step of calculating the probability that the electronic device successfully detects the target center frequency of the information frame from the base station through the frequency scan based on the first probability density function, the second probability density function, the third probability density function, and the fourth probability density function comprises: Based on the first probability density function and the fourth probability density function, a first probability is calculated that the calculation result of the cost function for the target center frequency point is greater than the calculation result of the cost function for other center frequencies in a first round of scanning of the electronic device. Based on the second probability density function and the fourth probability density function, a second probability is calculated that the calculation result of the cost function for the first adjacent center frequency point is greater than the calculation result of the cost function for other center frequency points in a second round of scanning of the electronic device. Based on the third probability density function and the fourth probability density function, a third probability is calculated that, in a third scan of the electronic device, the calculation result of the cost function at the second adjacent center frequency point is greater than the calculation result of the cost function at other center frequencies; and The probability that the electronic device successfully detects the target center frequency of the information frame from the base station is calculated based on the first probability, the second probability, and the third probability.

8. The electronic device of claim 7, wherein the number of multiple center frequency points to be scanned by the electronic device is 3*N, the number of center frequency points to be scanned in the first scan, the second scan, and the third scan of the electronic device are N respectively, and the center frequency points to be scanned in the first scan, the second scan, and the third scan of the electronic device will not repeat; and the frequency difference between two adjacent center frequency points of the multiple center frequency points is A, and the frequency difference between two adjacent center frequency points of the center frequency points to be scanned in the first scan, the second scan, and the third scan of the electronic device is 3*A.

9. The electronic device of claim 8, wherein N is 650 and A is 100 kHz.

10. The electronic device of claim 6, further comprising: Based on the calculated probability that the electronic device successfully detects the target center frequency point of the information frame from the base station, the method by which the electronic device scans the center frequency point is controlled.

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