A channel parameter estimation method based on multi-segment unique code frame structure for extending frequency offset estimation range

Abstract

A channel parameter estimation method based on multi-segment unique code frame structure for extending frequency offset estimation range mainly includes the following steps: sliding correlation estimation time delay; compensating time delay; accumulating phase angle; compensating phase jump; estimating frequency offset and phase offset. The method is used for signals containing multi-segment UW sequence frame structure, estimates symbol level time delay of the sequence through UW detection, and obtains frequency offset estimation value and phase offset estimation value through the way of accumulating phase angle after compensation. The phase jump compensation correction based on conditional judgment can effectively correct the deviation by using the phase angle change trend of the multi-segment correlation sequence, so as to achieve the purpose of improving the frequency offset estimation range.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a channel parameter estimation method based on a multi-segment unique code frame structure for extending the frequency offset estimation range. Background Technology

[0002] Time Division Multiple Access (TDMA) is an important multiple access technology used in military and satellite communications. Its basic principle is to divide the transmission time into multiple non-overlapping time slots of fixed length within the same transmission channel, which can be allocated to multiple users for communication. The frame is the basic unit of time in TDMA technology. Within a complete frame, multiple time slots are strictly allocated for data transmission by different users to control the order of use and avoid conflicts between users.

[0003] In TDMA burst communication, unique code (UW) sequences are often used in the signal for channel parameter synchronization based on the UW sequence. A UW sequence is a code sequence with special properties used to distinguish different users or signals. It exhibits good autocorrelation and cross-correlation characteristics and good anti-interference capabilities. By inserting a UW sequence into the transmitted signal, channel parameters can be estimated at the receiver by measuring the difference between the received signal and the known UW sequence. When multiple UW sequences exist in the signal frame structure, the sequence at the UW sequence position in the received signal can be multiplied and accumulated with the conjugate of the local UW sequence. Through calculation, channel parameters such as time delay, frequency offset, and phase offset can be estimated.

[0004] In principle, the larger the interval between multiple UW sequences, the larger the frequency offset estimation range. However, when the frame length is short, the interval between multiple UW sequences is limited. If the actual phase skips due to the influence of frequency offset, the read phase angle may deviate from the actual one by 2kπ, which will affect the frequency offset estimation result. Consequently, the frequency offset range that can be correctly estimated is also limited. Summary of the Invention

[0005] This disclosure provides a channel parameter estimation method based on a multi-segment unique code frame structure for expanding the frequency offset estimation range. For signals containing a multi-segment UW sequence frame structure, UW detection is performed on the sequence to estimate the symbol-level delay. After compensation, the frequency offset estimate and phase offset estimate are obtained by accumulating the phase angle. The phase angle change trend of the multi-segment related sequences is utilized, and the phase jump compensation correction based on condition judgment proposed in this disclosure can effectively correct the offset, thereby achieving the purpose of improving the frequency offset estimation range.

[0006] The channel parameter estimation method based on a multi-segment unique code frame structure for extending the frequency offset estimation range provided in this disclosure mainly includes the following steps:

[0007] S1, sliding correlation estimation delay;

[0008] S2, compensation for delay;

[0009] S3, cumulatively calculate the phase angle;

[0010] S4, compensates for phase jump;

[0011] S5 estimates frequency offset and phase offset.

[0012] Furthermore, the specific method of step S1 includes:

[0013] If the signal sequence has q A UW sequence, signal sequence The first in The symbol representation within a UW sequence is as follows:

[0014]

[0015] in, For signal amplitude, For frequency offset, For carrier frequency, For the sake of bias, For symbol-level delay, For maximum delay, For noise, For the first The starting position of each UW sequence. For the first The symbol length of a UW sequence;

[0016] The UW data of the signal sequence is multiplied by the conjugate of the UW local sequence modulated signal within a set window length to obtain a signal containing the offset after removing symbol information.

[0017]

[0018] in, The conjugate of the local UW sequence. For sliding index, It is half the length of the window, and satisfies ;

[0019] The signal is accumulated, and the result is compared to obtain the maximum accumulated value. The value is the symbol-level time delay estimate. :

[0020] .

[0021] Furthermore, in step S2, the compensation delay estimate is... Then, the biased signal associated with the local UW sequence is:

[0022] .

[0023] Furthermore, the specific method of step S3 includes:

[0024] The first The accumulated signals after demodulation of the UW sequences are obtained

[0025]

[0026] make , ,right Find the argument, and obtain the first... The cumulative argument of a UW sequence

[0027] .

[0028] Furthermore, the specific method of step S4 includes:

[0029] Due to frequency offset, phase jumps may occur during the phase accumulation process. Therefore, starting from the second UW, the phase jump offset is calculated using the phase difference, and the phase angle after the phase jump is iteratively updated.

[0030] .

[0031] Furthermore, the specific method of step S5 includes:

[0032] Set up a system of equations and solve it:

[0033]

[0034] The frequency offset estimate and the phase offset estimate are obtained:

[0035]

[0036] .

[0037] Furthermore, the method also includes the following steps:

[0038] S6, compensates for frequency offset and phase offset;

[0039] S7, demodulation and decoding.

[0040] Compared with the prior art, the beneficial effects of this disclosure are: ① For signals containing multiple UW sequence frame structures, UW detection is performed on the sequences to estimate symbol-level time delay. After compensation, the frequency offset estimate and phase offset estimate are obtained by accumulating the phase angle. The phase angle change trend of multiple related sequences is utilized, and phase jump compensation correction based on condition judgment can effectively correct the offset, thereby improving the frequency offset estimation range; ② Improve the frequency detection range; ③ Improve the quality of TDMA burst communication; ④ Low computational complexity. Attached Figure Description

[0041] The above and other objects, features and advantages of this disclosure will become more apparent from the more detailed description of exemplary embodiments of this disclosure taken in conjunction with the accompanying drawings, in which the same reference numerals generally represent the same components.

[0042] Figure 1 This is a schematic diagram of an exemplary frame structure;

[0043] Figure 2 This is a schematic diagram of the sliding correlation for time delay estimation;

[0044] Figure 3 This is a flowchart illustrating a process according to an exemplary embodiment of the present disclosure. Detailed Implementation

[0045] Preferred embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0046] This disclosure provides a channel parameter estimation method based on a multi-segment unique code frame structure for extending the frequency offset estimation range, mainly including the following steps:

[0047] S1, sliding correlation estimation delay;

[0048] S2, compensation for delay;

[0049] S3, cumulatively calculate the phase angle;

[0050] S4, compensates for phase jump;

[0051] S5 estimates frequency offset and phase offset.

[0052] In one exemplary implementation, as shown in the appendix Figure 1 As shown, suppose the signal sequence has a total of q If there are UW sequences, then the signal sequence The first in The symbols within a UW sequence can be represented as

[0053]

[0054] in, For signal amplitude, For frequency offset, For carrier frequency, For the sake of bias, For symbol-level delay, For maximum delay, For noise, For the first The starting position of each UW sequence. For the first The symbol length of a UW sequence.

[0055] The processing flow according to this disclosure is as follows: Figure 3 As shown, the main steps include:

[0056] 1. Sliding correlation estimation of time delay

[0057] The UW data of the signal sequence is multiplied by the conjugate of the UW local sequence modulated signal within a set window length to obtain a signal containing the offset after removing symbol information.

[0058]

[0059] in The conjugate of the local UW sequence. For sliding index, It is half the length of the window, and satisfies .

[0060] The signal is accumulated, and the result is compared to obtain the maximum accumulated value. The value is the symbol-level time delay estimate. :

[0061]

[0062] 2. Compensation for delay

[0063] Compensation delay estimate Then, the biased signal associated with the local UW sequence is:

[0064] .

[0065] 3. Accumulate and calculate phase angles

[0066] The first The accumulated signals after demodulation of the UW sequences are obtained

[0067]

[0068] make , ,right To find the argument, we can obtain the first... The cumulative argument of a UW sequence

[0069]

[0070] 4. Compensation for phase jump

[0071] Due to frequency offset, phase jumps may occur during the phase accumulation process. Therefore, starting from the second UW, the phase jump offset is calculated using the phase difference, and the phase angle after the phase jump is iteratively updated.

[0072]

[0073] 5. Estimate frequency offset and phase offset

[0074] Set up a system of equations and solve it:

[0075]

[0076] Then we can obtain the frequency offset estimate and the phase offset estimate:

[0077]

[0078] .

[0079] Among them when hour, Substituting into the equation yields...

[0080]

[0081] Therefore, in satisfying Under certain conditions, the frequency offset estimation range is improved compared to the case without phase jump compensation.

[0082] The increase is as follows:

[0083]

[0084] in , , , and All are carried over to the original angle. The calculation results at that time, and , .

[0085] 6. After applying this result, the subsequent processing steps also include frequency offset and phase offset compensation and demodulation decoding.

[0086] The above technical solutions are merely exemplary embodiments of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the specific embodiments of the present invention. Therefore, the methods described above are merely preferred and not restrictive.

Claims

1. A channel parameter estimation method based on a multi-segment unique code frame structure for extending the frequency offset estimation range, characterized in that, Includes the following steps: S1, sliding correlation estimation delay; S2, compensation for delay; S3, cumulatively calculate the phase angle; S4, compensates for phase jump; S5, estimates frequency offset and phase offset; The specific method of step S1 includes: If the signal sequence has q A UW sequence, signal sequence The first in The symbol representation within a UW sequence is as follows: in, For signal amplitude, For frequency offset, For carrier frequency, For the sake of bias, For symbol-level delay, For maximum delay, For noise, For the first The starting position of each UW sequence. For the first The symbol length of a UW sequence; The UW data of the signal sequence is multiplied by the conjugate of the UW local sequence modulated signal within a set window length to obtain a signal containing the offset after removing symbol information. in, The conjugate of the local UW sequence. For sliding index, It is half the length of the window, and satisfies ; The signal is accumulated, and the result is compared to obtain the maximum accumulated value. The value is the symbol-level time delay estimate. : ； In step S2, the compensation delay estimate is... Then, the biased signal associated with the local UW sequence is: 。 2. The method according to claim 1, characterized in that, The specific method of step S3 includes: The first The accumulated signals after demodulation of the UW sequences are obtained make , ,right Find the argument, and obtain the first... The cumulative argument of a UW sequence 。 3. The method according to claim 1, characterized in that, The specific method of step S4 includes: Due to frequency offset, phase jumps may occur during the phase accumulation process. Therefore, starting from the second UW, the phase difference is used to calculate the phase jump offset, and the phase angle after the phase jump is iteratively updated. 。 4. The method according to claim 1, characterized in that, The specific method of step S5 includes: Set up a system of equations and solve it: The frequency offset estimate and the phase offset estimate are obtained: 。 5. The method according to any one of claims 1-4, characterized in that, It also includes the following steps: S6, compensates for frequency offset and phase offset; S7, demodulation and decoding.

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