A synchronization method for receiving end signal of Bluetooth comprehensive tester

Abstract

The present invention discloses a synchronization method for a signal at a receiving end of a Bluetooth comprehensive tester, including detection of a Bluetooth frame header signal and fine synchronization of a Bluetooth frame header signal. The present invention establishes a preamble database of different frame rate types of Bluetooth signals, and according to different preamble autocorrelation characteristics, determines the frame rate of BLE by considering different correlation operation values ​​obtained at different frame rates; further distinguishes BLE, BR and EDR signals by combining the high-order cumulative quantity characteristics of Bluetooth signals; uses the difference between the synchronization sequence of EDR and the BR and BLE modes to calculate different peak-to-average ratios to determine and identify EDR frame modes; combines preambles, peak-to-average ratios and high-order cumulative quantities, as well as packet types to determine and identify the frame rate type of Bluetooth signals, and multiple determination conditions have obvious characteristic differences, ensuring that different Bluetooth signal frame rates can be accurately identified.

Description

Technical Field

[0001] The invention relates to a signal synchronization method, in particular to a synchronization method applied to a signal at a receiving end of a Bluetooth comprehensive tester, and belongs to the technical field of wireless communication signal processing. Background Art

[0002] Generally speaking, Bluetooth comprehensive testers (Bluetooth comprehensive testers) are widely used in the testing and performance evaluation of Bluetooth devices. Even Bluetooth-related chip testing cannot be separated from high-performance comprehensive testers. Therefore, the development of high-performance, reliable and accurate Bluetooth comprehensive testers is the guarantee for the generation and application of modern Bluetooth devices.

[0003] The development of the physical layer algorithm of the Bluetooth integrated tester is one of the most critical technologies of the entire integrated tester. Among them, the accurate synchronization positioning of the receiving end signal frame header in the physical layer algorithm is the basis of the entire Bluetooth integrated tester algorithm. Only when the signal frame header of the Bluetooth integrated tester receiving end is accurately located, can the frame header signal (including device information and data packet type information) be accurately parsed. Moreover, accurate synchronization of the frame header is a basic requirement for correctly demodulating the Bluetooth signal. Since the Bluetooth frame structure is divided into BR, EDR and BLE modes, and the frame structure and synchronization word of these three modes are different. Therefore, this brings certain uncertainties to the development of the physical layer receiving end algorithm of the Bluetooth integrated tester.

[0004] The research results of the physical layer receiving algorithm of Bluetooth signals are very mature, and some solutions in the prior art, such as a wireless comprehensive tester Bluetooth signal frame synchronization detection method disclosed in announcement number CN105657739B, realize the wireless comprehensive tester Bluetooth signal frame synchronization detection, and do not rely on the MAC address, and can ensure a certain degree of synchronization accuracy. However, there are certain differences between the physical layer receiving end synchronization method of the Bluetooth comprehensive tester and the signal synchronization of the Bluetooth device, especially in the process of engineering implementation, the physical layer synchronization of the Bluetooth comprehensive tester is related to the difference between sudden interference and various irregular signals, which brings certain difficulties to the synchronization of Bluetooth signals. Summary of the invention

[0005] The purpose of the present invention is to provide a synchronization method for the receiving end signal of a Bluetooth comprehensive tester in order to solve at least one of the above technical problems. The energy jump characteristics of the Bluetooth signal are utilized to obtain the impulse characteristics of the Bluetooth signal by taking the first-order differential of the received signal. The impulse characteristics are used to determine the rough starting position of the detected Bluetooth frame signal. Then, fine synchronization is performed according to the respective frame structures and synchronization words of BR, EDR and BLE. A technology for Bluetooth frame signal detection and frame header synchronization positioning in the development process of a Bluetooth comprehensive tester is proposed.

[0006] The present invention achieves the above-mentioned purpose through the following technical scheme: a synchronization method for a signal at a receiving end of a Bluetooth comprehensive tester, the synchronization method comprising the following steps:

[0007] Step 1: Detection of Bluetooth frame header signal

[0008] The detection of Bluetooth frame header signals consists of two parts: first, detecting whether there is an energy signal in the receiving end signal; second, detecting whether there is a Bluetooth frame header signal when there is an energy signal;

[0009] Step 2: Fine synchronization of Bluetooth frame header signal

[0010] If a Bluetooth frame header signal is detected, the Bluetooth tester receiver will accurately locate the starting position of the Bluetooth frame header signal before parsing the frame header information and demodulating;

[0011] Since the Bluetooth frame header signals BR, EDR and BLE frame structures are different, different fine synchronization schemes are used for the Bluetooth frame header signals BR, EDR and BLE during fine synchronization.

[0012] As a further technical solution of the present invention, in step 1:

[0013] Use the principle of signal energy jump to detect whether there is an energy signal, including:

[0014] The signal at the receiving end is differentiated in the first order. If there is a jump in energy, the impulse function is not 0. Otherwise, when there is no signal energy jump, the impulse function is 0.

[0015] If there is an energy jump, the current energy size is detected and lasts for a period of time, it is considered to be a Bluetooth frame header signal, otherwise it is considered to be a noise interference signal;

[0016] The signal at the receiving end is represented by R(t), where t is the time variable;

[0017] The receiving end signal R(t) is differentiated and expressed as:

[0018]

[0019] Where: A represents the amplitude of the impulse function, δ(t) is the impulse function of the receiving end signal R(t); a threshold TH is set, when A·δ(t)≥TH, it means that there is an energy signal jump and there may be a frame signal, otherwise it is considered that there is no frame signal; when A·δ(t)≥TH, the energy size of the received signal is recorded as E1; the energy size of the received signal is calculated as follows:

[0020] E(t)=|R(t)|

[0021] The time to maintain the current energy level is:

[0022] Δt=F(E(t)≥E1)

[0023] When the duration ΔT of the energy size of the detection signal is greater than a period ΔT, it is considered to be a frame of Bluetooth signal, otherwise it is considered to be a noise interference signal.

[0024] As a further technical solution of the present invention, in step 1:

[0025] If a Bluetooth frame header signal exists, detecting whether the Bluetooth frame header signal is a Bluetooth signal, using the preamble autocorrelation characteristic of the Bluetooth frame header signal for detection;

[0026] The preamble of the Bluetooth frame header signal is represented as P(t). The preamble P(t) and the received signal R(t) are correlated:

[0027]

[0028] in: is the correlation operation function, K is the correlation operation value; the K value is used to determine whether a Bluetooth signal exists.

[0029] As a further technical solution of the present invention, in step 2:

[0030] For the detailed positioning of the Bluetooth frame header signal BR, the 4-bit preamble code P(t) and the received signal R(t) are used for correlation operations, including:

[0031] The frame header of the Bluetooth frame header signal BR is located through the peak value of the correlation operation, and then the Bluetooth accessCode information is parsed using the located frame header;

[0032] Parse LAP information, header and packet type PacketType according to accessCode;

[0033] According to the parsed packet type PacketType, determine whether it belongs to the packet type of the Bluetooth frame header signal BR frame structure: NULL, POLL, FHS, DV, HV1, HV2, HV3, EV3, EV4, EV5, DM1, DH1, DM3, DH3, DM5 and DH5;

[0034] If it is a packet type of Bluetooth frame header signal BR, the Bluetooth frame header signal is correctly located and the next step of Bluetooth signal analysis is entered;

[0035] If it does not belong to the packet type of the Bluetooth frame header signal BR, go back to the frame header located by the previous related operation, move one symbol to the left or right as the starting point of the signal frame header to perform accessCode information parsing and packet type PacketType parsing, and again determine whether the detected packet type belongs to the BR packet type.

[0036] As a further technical solution of the present invention, in step 2:

[0037] For the detailed positioning of the Bluetooth frame header signal EDR, the 4-bit preamble of EDR is used to perform correlation calculation with the receiving end to locate the starting position of the frame header;

[0038] Use the synchronization word synEDR of the Bluetooth frame header signal EDR to perform correlation operation with the received signal R(t) to correct the starting position of the frame header, that is:

[0039]

[0040] According to the Bluetooth protocol, the synchronization sequence for EDR2M is:

[0041] syn2M=[0 0 0 1 1 1 0 1 1 1 0 1 1 1 1 1 0 1 0 1 0 1]

[0042] The synchronization sequence for EDR3M is:

[0043] syn3M=[0 0 0 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 1 1 1 0 1 0 0 1 0 01 0]

[0044] By positioning the relevant operation K EDR The peak position of (t) is moved forward by 131 symbols and is determined as the starting point of the frame header of the Bluetooth frame header signal EDR.

[0045] As a further technical solution of the present invention, in step 2:

[0046] Detailed positioning of the frame header of the Bluetooth frame header signal BLE, including:

[0047] Use the preamble P(t) of the Bluetooth frame header signal BLE and the received signal R(t) to perform correlation operations to locate the starting position of the frame header;

[0048] The preamble code P(t) of the Bluetooth frame header signal BLE is divided into three types: 8 bits, 16 bits and 80 bits;

[0049] The synchronization word synBLE of the Bluetooth frame header signal BLE is used to perform correlation operation with the received signal R(t), that is:

[0050]

[0051] By positioning the relevant operation K BLE The peak position of (t) is determined as the starting point of the BLE frame header.

[0052] The beneficial effects of the present invention are:

[0053] 1) The present invention establishes a preamble database of different frame rate types of Bluetooth signals, and determines the frame rate of BLE based on different preamble autocorrelation characteristics and different correlation operation values ​​obtained at different frame rates;

[0054] 2) The present invention combines the high-order cumulative amount characteristics of Bluetooth signals to further distinguish BLE, BR and EDR signals, avoiding the recognition error caused by the preamble code autocorrelation calculation;

[0055] 3) The present invention uses the difference between the synchronization sequence of EDR and the BR and BLE modes to calculate different peak-to-average ratios to judge and identify the EDR frame mode;

[0056] 4) The present invention combines the preamble, peak-to-average ratio and high-order cumulative amount, as well as the packet type to determine the type of Bluetooth signal frame rate. Multiple determination conditions have obvious characteristic differences, which ensures that different Bluetooth signal frame rates can be accurately identified;

[0057] 5) The method of the present invention can have strong robustness in testing various parameters of a Bluetooth comprehensive tester in an environment with strong noise interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 Step characteristics and impulse characteristics diagrams simulated for Bluetooth signals;

[0059] Figure 2 This is a flowchart of Bluetooth signal frame header synchronization of the present invention;

[0060] Figure 3 The fine synchronization EDR signal synchronization sequence related characteristics of the present invention;

[0061] Figure 4 This is the related characteristics of the BLE signal synchronization sequence of the fine synchronization of the present invention. DETAILED DESCRIPTION

[0062] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] Embodiment, the present invention provides a method for synchronizing the signal of a Bluetooth integrated tester receiving end, the synchronization method performs coarse synchronization and fine synchronization based on the impulse characteristics, frame preamble and synchronization word of the Bluetooth signal, that is, includes coarse synchronization of the Bluetooth signal (detection of the Bluetooth frame header signal) and fine synchronization of the Bluetooth signal (fine synchronization of the Bluetooth frame header signal).

[0064] Among them, for the rough synchronization of Bluetooth signals, it is necessary to roughly detect the starting point of the Bluetooth signal. The present invention uses the first-order derivative of the receiving end signal to obtain the signal jump situation. The principle is to regard the Bluetooth signal as a step function, and the first-order derivative of the step function can obtain its impulse jump position. When the impulse jump occurs, it is considered to be the starting point of the Bluetooth signal. When the impulse function jumps upward, it is the starting point, and when it jumps downward, it is considered to be the end point. Figure 1 As shown in the figure. After roughly detecting the starting point of the Bluetooth signal, the frame mode of the Bluetooth signal, namely BR, EDR and BLE, needs to be detected first. For BR, EDR and BLE frames, their respective preamble codes and synchronization words are used for fine synchronization.

[0065] The synchronization process, such as Figure 2 As shown:

[0066] First: detection of Bluetooth frame header signal.

[0067] The detection of Bluetooth frame header signals includes two parts: one is to detect whether there is an energy signal (whether there is a truly useful signal) at the receiving end; the other is to detect whether there is a Bluetooth frame header signal when there is an energy signal.

[0068] Regarding "one", the principle of signal energy jump is used to detect whether there is an energy signal. The specific steps include:

[0069] The signal at the receiving end of the Bluetooth comprehensive tester is differentiated once. If there is a jump in energy, the impulse function is not 0, otherwise the impulse function is 0 (when there is no signal energy jump);

[0070] If there is an energy jump, the current energy size is detected and lasts for a period of time, it is considered to be a Bluetooth frame header signal, otherwise it is considered to be a noise interference signal;

[0071] The signal at the receiving end is represented by R(t), where t is the time variable;

[0072] The receiving end signal R(t) is differentiated and expressed as:

[0073]

[0074] Where: A represents the amplitude of the impulse function, δ(t) is the impulse function of the receiving end signal R(t); a threshold TH is set, when A·δ(t)≥TH, it means that there is an energy signal jump and there may be a frame signal, otherwise it is considered that there is no frame signal; when A·δ(t)≥TH, the energy size of the received signal is recorded as E1; the energy size of the received signal is calculated as follows:

[0075] E(t)=|R(t)|

[0076] The time to maintain the current energy level is:

[0077] Δt=F(E(t)≥E1)

[0078] When the duration ΔT of the energy size of the detection signal is greater than a period ΔT, it is considered to be a frame of Bluetooth signal, otherwise it is considered to be a noise interference signal.

[0079] Regarding "Second", detection is performed based on the autocorrelation of the leading code of the Bluetooth frame header signal. The specific steps include:

[0080] The preamble of the Bluetooth frame header signal is represented as P(t). The preamble P(t) and the received signal R(t) are correlated:

[0081]

[0082] in: is the correlation operation function, K is the correlation operation value; the K value is used to determine whether a Bluetooth signal exists.

[0083] Second: fine synchronization of Bluetooth frame header signal.

[0084] When a Bluetooth frame header signal is detected, the receiving end of the Bluetooth comprehensive tester needs to accurately locate the starting position of the Bluetooth frame header signal before parsing the frame header information and demodulating; and because the frame structures of Bluetooth frame header signals BR, EDR and BLE are different, different fine synchronization schemes are used for Bluetooth frame header signals BR, EDR and BLE during fine synchronization.

[0085] 1) For the fine positioning of the frame header of the Bluetooth frame header signal BR, the 4-bit preamble code P(t) and the received signal R(t) are used for correlation operation. The correlation operation formula is:

[0086] The frame header of the Bluetooth frame header signal BR is located through the peak value of the correlation operation, and then the Bluetooth accessCode information is parsed using the located frame header;

[0087] According to the parsed packet type PacketType, determine whether it belongs to the packet type of the Bluetooth frame header signal BR frame structure: NULL, POLL, FHS, DV, HV1, HV2, HV3, EV3, EV4, EV5, DM1, DH1, DM3, DH3, DM5 and DH5;

[0088] If it is a packet type of Bluetooth frame header signal BR, the Bluetooth frame header signal is correctly located and the next step of Bluetooth signal analysis is entered;

[0089] If it does not belong to the packet type of the Bluetooth frame header signal BR, go back to the frame header located by the previous related operation, move one symbol to the left or right as the starting point of the signal frame header to perform accessCode information parsing and packet type PacketType parsing, and again determine whether the detected packet type belongs to the BR packet type.

[0090] 2) For the detailed positioning of the frame header of the Bluetooth frame header signal EDR, the 4-bit preamble code of EDR is used to perform correlation calculation with the receiving end to locate the starting position of the frame header;

[0091] Use the synchronization word synEDR of the Bluetooth frame header signal EDR to perform correlation operation with the received signal R(t) to correct the starting position of the frame header, that is:

[0092]

[0093] According to the Bluetooth protocol, the synchronization sequence for EDR2M is:

[0094] syn2M=[0 0 0 1 1 1 0 1 1 1 0 1 1 1 1 1 0 1 0 1 0 1]

[0095] The synchronization sequence for EDR3M is:

[0096] syn3M=[0 0 0 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 1 1 1 0 1 0 0 1 0 01 0]

[0097] By positioning the relevant operation K EDR The peak position of (t) is moved forward by 131 symbols and is determined as the starting point of the frame header of the Bluetooth frame header signal EDR.

[0098] In this embodiment, the synchronization word related characteristics of the simulated EDR2M and EDR3M fine synchronization are as follows: Figure 3As shown in the figure, it can be seen that the correlation peaks of EDR2M and EDR3M are very obvious, and the position of the peak is the position of the synchronization word starting point of the EDR signal. Through this synchronization word starting point, the present invention can clearly locate the starting point of the Bluetooth signal frame and the position of other frame information.

[0099] 3) Detailed positioning of the frame header of the Bluetooth frame header signal BLE, including:

[0100] Use the preamble P(t) of the Bluetooth frame header signal BLE and the received signal R(t) to perform correlation operations to locate the starting position of the frame header;

[0101] The preamble code P(t) of the Bluetooth frame header signal BLE is divided into three types: 8 bits, 16 bits and 80 bits;

[0102] The synchronization word synBLE of the Bluetooth frame header signal BLE is used to perform correlation operation with the received signal R(t), that is:

[0103]

[0104] By positioning the relevant operation K BLE The peak position of (t) is determined as the starting point of the BLE frame header.

[0105] In this embodiment, the synchronization word related characteristics of the simulated BLE fine synchronization are as follows: Figure 4 As shown. From the figure, it can be seen that the BLE signal synchronization word related peaks are very obvious, and the position of the peak is the position of the synchronization word starting point of the BLE signal. Through this synchronization word starting point, the present invention can clearly locate the starting point of the BLE Bluetooth signal frame and the position of other frame information.

[0106] Working principle: For the coarse synchronization of Bluetooth signals, it is necessary to roughly detect the starting point of the Bluetooth signal. The present invention uses the first-order derivative of the receiving end signal to obtain the signal jump situation. The principle here is to regard the Bluetooth signal as a step function, and the first-order derivative of the step function can obtain its impulse jump position. When the impulse jump occurs, the position is considered to be the starting point of the Bluetooth signal. When the impulse function jumps upward, it is the starting point, and when it jumps downward, it is considered to be the end point. After roughly detecting the starting point of the Bluetooth signal, it is necessary to first detect the frame mode of the Bluetooth signal, namely BR, EDR and BLE. For BR, EDR and BLE frames, their respective preamble codes and synchronization words are used for fine synchronization.

[0107] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0108] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A synchronization method for receiving end signals of a Bluetooth comprehensive tester, characterized in that: The synchronization method comprises the following steps: Step 1: Detection of Bluetooth frame header signal The detection of Bluetooth frame header signals consists of two parts: first, detecting whether there is an energy signal in the receiving end signal; second, detecting whether there is a Bluetooth frame header signal when there is an energy signal; Step 2: Fine synchronization of Bluetooth frame header signal If a Bluetooth frame header signal is detected, the Bluetooth tester receiver will accurately locate the starting position of the Bluetooth frame header signal before parsing the frame header information and demodulating; Since the Bluetooth frame header signals BR, EDR and BLE frame structures are different, different fine synchronization schemes are used for the Bluetooth frame header signals BR, EDR and BLE during fine synchronization. In the step 1, the principle of signal energy jump is used to detect whether there is an energy signal, which specifically includes: The signal at the receiving end is differentiated in the first order. If there is a jump in energy, the impulse function is not 0. Otherwise, when there is no signal energy jump, the impulse function is 0. If there is an energy jump, the current energy size is detected and lasts for a period of time, it is considered to be a Bluetooth frame header signal, otherwise it is considered to be a noise interference signal; The signal at the receiving end is represented by R(t), where t is the time variable; The receiving end signal R(t) is differentiated and expressed as: Where: A represents the amplitude of the impulse function, δ(t) is the impulse function of the receiving end signal R(t); a threshold TH is set, when A·δ(t)≥TH, it means that there is an energy signal jump and there may be a frame signal, otherwise it is considered that there is no frame signal; when A·δ(t)≥TH, the energy size of the received signal is recorded as E1; the energy size of the received signal is calculated as follows: E(t)=|R(t)| The time to maintain the current energy level is: Δt=F(E(t)≥E1) When the duration ΔT of the energy of the detection signal is greater than a period of time, it is considered to be a frame of Bluetooth signal, otherwise it is considered to be a noise interference signal.

2. The synchronization method according to claim 1, characterized in that: In the step 1: If a Bluetooth frame header signal exists, detecting whether the Bluetooth frame header signal is a Bluetooth signal, using the preamble autocorrelation characteristic of the Bluetooth frame header signal for detection; The preamble of the Bluetooth frame header signal is represented as P(t). The preamble P(t) and the received signal R(t) are correlated: in: is the correlation operation function, K is the correlation operation value; the K value is used to determine whether a Bluetooth signal exists.

3. The synchronization method according to claim 2, characterized in that: In the step 2: For the detailed positioning of the Bluetooth frame header signal BR, the 4-bit preamble code P(t) and the received signal R(t) are used for correlation operations, including: The frame header of the Bluetooth frame header signal BR is located through the peak value of the correlation operation, and then the Bluetooth accessCode information is parsed using the located frame header; Parse LAP information, header and packet type PacketType according to accessCode; According to the parsed packet type PacketType, determine whether it belongs to the packet type of the Bluetooth frame header signal BR frame structure: NULL, POLL, FHS, DV, HV1, HV2, HV3, EV3, EV4, EV5, DM1, DH1, DM3, DH3, DM5 and DH5; If it is a packet type of Bluetooth frame header signal BR, the Bluetooth frame header signal is correctly located and the next step of Bluetooth signal analysis is entered; If it does not belong to the packet type of the Bluetooth frame header signal BR, go back to the frame header located by the previous related operation, move one symbol to the left or right as the starting point of the signal frame header to perform accessCode information parsing and packet type PacketType parsing, and again determine whether the detected packet type belongs to the BR packet type.

4. The synchronization method according to claim 1, characterized in that: In the step 2: For the detailed positioning of the Bluetooth frame header signal EDR, the 4-bit preamble of EDR is used to perform correlation calculation with the receiving end to locate the starting position of the frame header; Use the synchronization word synEDR of the Bluetooth frame header signal EDR to perform correlation operation with the received signal R(t) to correct the starting position of the frame header, that is: According to the Bluetooth protocol, the synchronization sequence for EDR2M is: syn2M=[0 0 0 1 1 1 0 1 1 1 0 1 1 1 1 1 0 1 0 1 0 1] The synchronization sequence for EDR3M is: syn3M=[0 0 0 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1 1 1 1 1 0 1 0 0 1 0 0 10] By positioning the relevant operation K EDR The peak position of (t) is moved forward by 131 symbols and is determined as the starting point of the frame header of the Bluetooth frame header signal EDR.

5. The synchronization method according to claim 4, characterized in that: In the step 2: Detailed positioning of the frame header of the Bluetooth frame header signal BLE, including: Use the preamble P(t) of the Bluetooth frame header signal BLE and the received signal R(t) to perform correlation operations to locate the starting position of the frame header; The preamble code P(t) of the Bluetooth frame header signal BLE is divided into three types: 8 bits, 16 bits and 80 bits; The synchronization word synBLE of the Bluetooth frame header signal BLE is used to perform correlation operation with the received signal R(t), that is: By positioning the relevant operation K BLE The peak position of (t) is determined as the starting point of the BLE frame header.

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