A method and system for fast generation of nr-5g restricted set prach sequences

Abstract

The application discloses a kind of NR-5G restriction set PRACH sequence fast generation method and system, the method includes the following steps: S1: the mapping table of logical root sequence number i to du is established;S2: whether du satisfies the relationship formula of cyclic shift NCS and frequency domain data length LRA is judged;S3: the intermediate variable of cyclic shift value Cv is calculated;S4: the number of available cyclic shift values Cv corresponding to current logical root sequence number i and the value of each cyclic shift value Cv are calculated;S5: the number of cyclic shift values Cv and the value of each cyclic shift value Cv calculated in step S4 are filled in the mapping table in step S1;S6: after user equipment UE is started, PRACH sending sequence is generated according to physical root sequence number u and the value of cyclic shift value Cv.The application can quickly generate all the PRACH sequences sent.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a method and system for rapidly generating NR-5G restricted set PRACH sequences. Background Technology

[0002] When an NR-5G millimeter-wave satellite base station and a UE (User Equipment) perform uplink synchronization, random access must first be completed. The UE obtains PRACH resource information from the SIB1 (System Information Block) message sent by the base station through downlink synchronization, generates a corresponding preamble sequence using a random Preamble-Id, and sends it to the base station to complete the transmission of the random preamble sequence. The 3GPP protocol proposes LRA=839 points to support restricted set PRACH sequences. Due to the significant Doppler shift in communication between the terrestrial UE and the satellite, restricted set PRACH signals have a stronger anti-Doppler shift effect than unrestricted set PRACH signals.

[0003] In NR5G (New Radio) millimeter-wave systems, satellite base stations transmit NR5G millimeter-wave SSB signals to ground-based UEs. After downlink synchronization, the ground-based UEs can obtain PRACH configuration information and generate a preamble random sequence by demodulating SIB1 system messages. The generation formula is as follows:

[0004]

[0005] The UE needs to look up the physical root sequence number u using the logical root sequence number i in a table. A set of preamble sequences x can then be generated using the physical root sequence number u. u (i). Based on the zero-correlation zone configuration value (zeroCorrelationZoneConfig) in the PRACH configuration information, the frequency domain data length LRA of NCS and PRACH is obtained by looking up the table. The Preamble ID number to be transmitted can then be used to calculate Cv (cyclic shift value), thereby generating the PRACH signal x corresponding to Preamble ID. u,v (i), and x u,v (i) Use DFT transform to convert to the frequency domain and generate the PRACH frequency domain signal y. u,v (n).

[0006] The formula for generating Cv is as follows:

[0007]

[0008]

[0009] For restricted PRACH sequences, the following steps are required to generate intermediate values ​​for Cv:

[0010] Where (q*u)mod LRA=1, q is the smallest integer, u is the physical root sequence number, LRA is the sequence length of PRACH, LRA=839 in 5G, and mod represents the modulo operation.

[0011] Taking restricted set type A as an example, the intermediate parameters of Cv are calculated as follows:

[0012]

[0013]

[0014]

[0015]

[0016]

[0017] In an unrestricted PRACH sequence, once the NCS and LRA are determined, the base sequence value is divided into LRA / NCS parts. Therefore, this base sequence can be cyclically shifted to produce a maximum of LRA / NCS preamble sequences. Since the protocol defines 64 preamble sequences with IDs from 0 to 63, 64 preamble sequences need to be calculated. If there are fewer than 64 preamble sequences, the logical root sequence index is added until 64 preamble sequences are generated. Finally, a preamble sequence is randomly selected from these 64 preamble sequences as the random access preamble sequence.

[0018] From the Cv generation formula above, we know that v represents the Preamble ID. Since there are a total of 64 random access Preamble IDs, if the current root sequence has fewer than 64 Cvs, the next root sequence number is used to continue generating the preamble sequence, and Cv is regenerated to complete the PRACH sequence generation of the corresponding Preamble ID (3GPP 38.211 6.3.3.1).

[0019] For example, under unrestricted set conditions, the number of Cv sequences and their values ​​can be obtained from the base sequence at the current root sequence number based on LRA and NCS. If Lra = 839 and Ncs = 32, then the range of v is 0, 1, ..., 25. To generate a sequence with PreambleId = 27, the preceding base sequence x is regenerated using the next physical root sequence number u. u (i), and v takes the value of 2 to obtain Cv, thereby generating x. u,v(i). For the PRACH constraint set conditions, the steps to generate Cv are more complex, requiring the calculation of multiple intermediate variables and checking whether du meets the conditions. If 64 sequences are to be generated, it will inevitably bring a large amount of computation to the UE.

[0020] Patent CN111315034A discloses a method and apparatus for generating a random access preamble sequence. The method proposes a method for generating a random access preamble sequence, the main idea of ​​which is to obtain du by looking up a table using the logical root sequence number, and then, according to the formula for the constraint set, determine whether du satisfies the preset conditions between du and NCS and LRA. If satisfied, Cv is calculated based on the random Preamble Id value k; otherwise, Cv = 0. The innovation of this patent lies in the use of the formula:

[0021]

[0022] u can be obtained by looking up the table using the logical root sequence number, and du can be obtained according to the above formula, thus establishing a correspondence between logical root sequence number and du. By pre-calculating du corresponding to each root sequence number, the value of du can be quickly obtained by looking up the table using the root sequence number, reducing the amount of real-time calculation.

[0023] However, the description in this patent does not reduce the calculation of Cv for generating the Preamble ID value k. If the value of k is 63, the method described in the patent will still iterate through and calculate Cv until Cv = 63 is calculated, without significantly solving the time-consuming problem. Furthermore, the patent description misunderstands the protocol, stating that if du does not meet the preset conditions between NCS and LRA, then Cv is determined to be equal to 0. That is, Cv being 0 indicates that the current base sequence can be used as a transmission sequence for a Preamble ID. However, 3GPP 38.211 6.3.3.1 states that if du does not meet the preset conditions between NCS and LRA, then there is no Cv, the current root sequence number is unusable, and the preceding base sequence x generated by the current physical root sequence is... u (i) Not available. Du needs to be recalculated using the physical root sequence u of the next logical root sequence, and it needs to be verified whether Du satisfies the preset conditions between NCS and LRA. Cv can only be calculated when Du satisfies the preset conditions between NCS and LRA, and the physical root sequence u corresponding to the current logical root sequence can be used to generate the leading basis sequence. Summary of the Invention

[0024] The purpose of this invention is to provide a method and system for rapidly generating NR-5G restricted set PRACH sequences, in order to solve the technical problem that the generation of restricted set PRACH sequences (preamble sequences) by UEs during random access is time-consuming in the prior art.

[0025] This invention is achieved using the following technical solution: a method for rapidly generating NR-5G restricted set PRACH sequences, comprising the following steps:

[0026] S1: Based on the mapping table from logical root sequence number i to physical root sequence number u, calculate du corresponding to each root sequence and establish the mapping table from logical root sequence number i to du.

[0027] S2: Determine whether du satisfies the relationship between the cyclic shift NCS and the frequency domain data length LRA;

[0028] S3: Based on the judgment result of step S2, calculate the intermediate variable of the cyclic shift value Cv;

[0029] S4: Based on the intermediate variables calculated in step S3, calculate the number of available cyclic shift values ​​Cv corresponding to the current logical root sequence number i and the value of each cyclic shift value Cv;

[0030] S5: Fill the number of cyclic shift values ​​Cv calculated in step S4 and the value of each cyclic shift value Cv into the mapping table in step S1;

[0031] S6: When the user equipment (UE) is powered on, it generates a PRACH transmission sequence based on the physical root sequence number u and the cyclic shift value Cv.

[0032] Further, step S1 specifically involves obtaining the physical root sequence number u from the logical root sequence number i using Table 6.3.3.1-3 of 3GPP 38.211, calculating du based on the physical root sequence number u and the frequency domain data length LRA, and then establishing a correspondence table between the logical root sequence number i and du.

[0033] Furthermore, du is calculated according to the formula (qu)mod LRA=1, and the value of du is mapped to the logical root sequence number i.

[0034] Furthermore, if du does not satisfy the relationship between the cyclic shift NCS and the frequency domain data length LRA, then the corresponding logical root sequence number i is marked as unavailable; if du satisfies the relationship between the cyclic shift NCS and the frequency domain data length LRA, then the corresponding logical root sequence number i is marked as available.

[0035] Furthermore, based on the available logical root sequence number i and the corresponding physical root sequence number u and du, the cyclic shift NCS, and the frequency domain data length LRA, the intermediate variables of the cyclic shift value Cv are calculated, and the intermediate variables include: d start .

[0036] Furthermore, the formula for calculating the number of cyclic shift values ​​Cv is: Where w is the number of cyclic shift values ​​Cv corresponding to the logical root sequence number i, and A is the constraint set.

[0037] Further, step S5 specifically involves filling the number of cyclic shift values ​​Cv and the value of each cyclic shift value Cv into the mapping table in step S1, and obtaining the results corresponding to the available logical root sequence number i by looking up the table, including the physical root sequence number u, du, the number of cyclic shift values ​​Cv, and the value of each cyclic shift value Cv.

[0038] Further, step S6 specifically involves: After the user equipment (UE) powers on and completes downlink synchronization, and after parsing the SIB1 message, when preparing to generate the PRACH sequence, it first looks up the corresponding physical root sequence number u and cyclic shift value Cv using the PRACH logical root sequence number i, frequency domain data length LAR, cyclic shift NCS, and random number Preamble-Id value in SIB1. A base sequence is generated using the physical root sequence number u, and then the base sequence is cyclically shifted according to the length of the cyclic shift value Cv to generate the PRACH transmission sequence.

[0039] A rapid generation system for NR-5G restricted set PRACH sequences includes a mapping table establishment module, a calculation module, a filling module, and a user equipment (UE). The mapping table establishment module is used to establish a mapping table from logical root sequence number i to the corresponding du of each root sequence. The calculation module is used to calculate the du corresponding to each root sequence, and determine whether du satisfies the relationship between cyclic shift (NCS) and frequency domain data length (LRA). Based on the determination result, it calculates the intermediate variable of cyclic shift value Cv, and based on the intermediate variable, calculates the number of available cyclic shift values ​​Cv corresponding to the current logical root sequence number i and the value of each cyclic shift value Cv. The filling module is used to fill the number of cyclic shift values ​​Cv and the value of each cyclic shift value Cv into the mapping table in step S1. After the user equipment (UE) is powered on, it generates a PRACH transmission sequence based on the physical root sequence number u and the value of the cyclic shift value Cv.

[0040] The beneficial effects of this invention are as follows: By pre-calculating the number w and Cv value corresponding to the logical root sequence number i, the UE can quickly obtain the Cv value and the corresponding physical root sequence number u before sending any random Preamble Id, thereby quickly generating all transmitted PRACH sequences. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0042] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0046] Example 1

[0047] See Figure 1 A method for rapidly generating NR-5G restricted set PRACH sequences includes the following steps:

[0048] S1: Based on the mapping table from logical root sequence number i to physical root sequence number u, calculate du corresponding to each root sequence and establish the mapping table from logical root sequence number i to du.

[0049] S2: Determine whether du satisfies the relationship between the cyclic shift NCS and the frequency domain data length LRA;

[0050] S3: Based on the judgment result of step S2, calculate the intermediate variable of the cyclic shift value Cv;

[0051] S4: Based on the intermediate variables calculated in step S3, calculate the number of available cyclic shift values ​​Cv corresponding to the current logical root sequence number i and the value of each cyclic shift value Cv;

[0052] S5: Fill the number of cyclic shift values ​​Cv calculated in step S4 and the value of each cyclic shift value Cv into the mapping table in step S1;

[0053] S6: When the user equipment (UE) is powered on, it generates a PRACH transmission sequence based on the physical root sequence number u and the cyclic shift value Cv.

[0054] In this embodiment, step S1 specifically involves: obtaining the physical root sequence number u from Table 6.3.3.1-3 of 3GPP 38.211 using the logical root sequence number i; calculating du based on the physical root sequence number u and the frequency domain data length LRA; and then establishing a correspondence table between the logical root sequence number i and du. Later, the number of Cv values ​​and their corresponding values ​​will be added to this table; that is, each logical root sequence in this table will map to u, du, the number of Cv values, and the value of Cv.

[0055] Furthermore, du is calculated according to the formula (qu)mod LRA=1, and the value of du is mapped to the logical root sequence number i.

[0056] Furthermore, if du does not satisfy the relationship between the cyclic shift NCS and the frequency domain data length LRA, then the corresponding logical root sequence number i is marked as unusable, and the mapping content of these unusable logical root sequence numbers i in the mapping table is deleted; if du satisfies the relationship between the cyclic shift NCS and the frequency domain data length LRA, then the corresponding logical root sequence number i is marked as usable.

[0057] Furthermore, based on the available logical root sequence number i and the corresponding physical root sequence number u and du, the cyclic shift NCS, and the frequency domain data length LRA, the intermediate variables of the cyclic shift value Cv are calculated, and the intermediate variables include: d start .

[0058] Furthermore, the formula for calculating the number of cyclic shift values ​​Cv is: Where w is the number of cyclic shift values ​​Cv corresponding to the logical root sequence number i, and A is the constraint set.

[0059] Further, step S5 specifically involves filling the number of cyclic shift values ​​Cv and the value of each cyclic shift value Cv into the mapping table in step S1, and obtaining the results corresponding to the available logical root sequence number i by looking up the table, including the physical root sequence number u, du, the number of cyclic shift values ​​Cv, and the value of each cyclic shift value Cv.

[0060] Further, step S6 specifically involves: After the User Equipment (UE) powers on, completes downlink synchronization, and parses the SIB1 message, when preparing to generate the PRACH sequence, it first looks up the corresponding physical root sequence number u and cyclic shift value Cv using the PRACH logical root sequence number i, frequency domain data length LAR, cyclic shift NCS, and random number Preamble-Id value from SIB1. A base sequence is generated using the physical root sequence number u, and then the base sequence is cyclically shifted according to the length of the cyclic shift value Cv to generate the PRACH transmission sequence. Specifically, if the UE needs to send a random preamble Id value k, it starts looking up the table from the logical root sequence number i in the SIB1 message. Assuming each root sequence number has 5 Cv values, if the current k is 3, then the 4th Cv value mapped to the logical root sequence number i in Table 1 and u are used as the Cv and u of the current UE's PRACH sequence. If k is greater than 4, then accumulate the Cv counts of the current logical root sequence number i and the next logical root sequence number i+1, and check if the total number is greater than k. If it is not greater than k, continue accumulating the Cv count of i+2 until it is greater than k (denoted as the current logical root sequence number i+r). At this point, find the logical root sequence number i+r, its mapped physical root sequence number u, and the Cv corresponding to the Preamble Id value k. Finally, the UE generates the PRACH transmission sequence based on the u and Cv values.

[0061] For example, when LRA = 839 and the zero correlation zone config = 0, NCS = 15. Logical root sequence number i can only start from 24, because numbers from 0 to 23 and 820-837 cannot be used for PRACH sequence generation because du does not satisfy the relationship between LRA and NCS. The number of Cv and the value of Cv for each root sequence number can be calculated by combining u with NCS for logical root sequence numbers from 24 to 819. For example, taking logical root sequence number 24 as an example, its corresponding physical root sequence number u = 56, the calculated number of Cv w = 18, and its Cv values ​​are as follows:

[0062] Cv=0 45 90 135 180 225 270 315 360 405 450495 540 585 630 675 720765.

[0063] Taking logical root sequence number 25 as an example, its corresponding physical root sequence number u = 783, the calculated number of Cv is w = 18, and its Cv value is as follows:

[0064] Cv=0 45 90 135 180 225 270 315 360 405 450495 540 585 630 675 720765.

[0065] Taking logical root sequence number 26 as an example, its corresponding physical root sequence number u = 112, then the number of Cv is calculated to be w = 14, and its Cv value is as follows:

[0066] Cv=0 30 60 90 120 150 180 210 240 270300 330 360 390.

[0067] Taking logical root sequence number 27 as an example, its corresponding physical root sequence number u = 727, then the calculated number of Cv is w = 14, and its Cv value is as follows:

[0068] Cv=0 30 60 90 120 150 180 210 240 270300 330 360 390.

[0069] If the base station's configured logical root sequence number is 24: For the UE to send a PRACH sequence with Preamble Id 2, since logical root sequence number 24 contains 18 Cv values, the Preamble Id 2 requires a Cv value of 90 and an u value of 56. For the UE to send a PRACH sequence with Preamble Id 19, since logical root sequence number 24 contains 18 Cv values, the current root sequence number can only generate 18 Preamble Ids (0-17). Since Preamble Id 19, the next logical root sequence number is needed to continue generating the PRACH sequence. Logical root sequence number 25 contains 18 Cv values, which meets the requirement, thus generating a Preamble Id 20 with a Cv value of 45 and an u value of 783.

[0070] A rapid NR-5G restricted set PRACH sequence generation system is provided to implement the aforementioned rapid NR-5G restricted set PRACH sequence generation method. The system includes a mapping table establishment module, a calculation module, a filling module, and a user equipment (UE). The mapping table establishment module establishes a mapping table from logical root sequence number i to the corresponding du of each root sequence. The calculation module calculates the du corresponding to each root sequence and determines whether du satisfies the relationship between cyclic shift (NCS) and frequency domain data length (LRA). Based on the determination result, it calculates an intermediate variable for the cyclic shift value Cv and, based on the intermediate variable, calculates the number of available cyclic shift values ​​Cv corresponding to the current logical root sequence number i and the value of each cyclic shift value Cv. The filling module fills the number of cyclic shift values ​​Cv and the value of each cyclic shift value Cv into the mapping table in step S1. After the user equipment (UE) is powered on, it generates a PRACH transmission sequence based on the physical root sequence number u and the value of the cyclic shift value Cv.

[0071] This invention, under the premise of a restricted PRACH set, allows the UE to quickly obtain the physical root sequence number u and corresponding Cv value of the corresponding Preamble ID by looking up the root sequence number in a table, based on the logical root sequence number and NCS configured by the base station, thus rapidly generating the PRACH restricted set sequence. This avoids the need to generate 64 preamble sequences during random access, reducing the time and computational load of generating preamble sequences and improving system efficiency. It also avoids situations where the logical root sequence number issued by the base station does not meet the constraints of du, NCS, and LRA, quickly finding a suitable logical root sequence number and rapidly generating the PRACH restricted set sequence.

[0072] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily essential to this application.

[0073] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Modifications and variations made by those skilled in the art without departing from the spirit and scope of the invention should be within the protection scope of the appended claims.

Claims

1. A method for rapidly generating NR-5G restricted set PRACH sequences, characterized in that, Includes the following steps: S1: Based on the mapping table from logical root sequence number i to physical root sequence number u, calculate du corresponding to each root sequence and establish the mapping table from logical root sequence number i to du. S2: Determine whether du satisfies the relationship between the cyclic shift NCS and the frequency domain data length LRA; S3: Based on the judgment result of step S2, calculate the intermediate variable of the cyclic shift value Cv; S4: Based on the intermediate variables calculated in step S3, calculate the number of available cyclic shift values ​​Cv corresponding to the current logical root sequence number i and the value of each cyclic shift value Cv; S5: Fill the number of cyclic shift values ​​Cv calculated in step S4 and the value of each cyclic shift value Cv into the mapping table in step S1; S6: When the user equipment (UE) is powered on, it generates a PRACH transmission sequence based on the physical root sequence number u and the cyclic shift value Cv.

2. The method for rapid generation of NR-5G restricted set PRACH sequences as described in claim 1, characterized in that, Step S1 specifically involves: obtaining the physical root sequence number u through the logical root sequence number i, calculating du based on the physical root sequence number u and the frequency domain data length LRA, and then establishing a correspondence table between the logical root sequence number i and du.

3. The method for rapid generation of NR-5G restricted set PRACH sequences as described in claim 1, characterized in that, The value of du is calculated using the formula (qu) mod LRA = 1, and then mapped to the logical root sequence number i.

4. The method for rapid generation of NR-5G restricted set PRACH sequences as described in claim 3, characterized in that, If du does not satisfy the relationship between the cyclic shift NCS and the frequency domain data length LRA, then the corresponding logical root sequence number i is marked as unavailable; if du satisfies the relationship between the cyclic shift NCS and the frequency domain data length LRA, then the corresponding logical root sequence number i is marked as available.

5. The method for rapid generation of NR-5G restricted set PRACH sequences as described in claim 4, characterized in that, Based on the available logical root sequence number i and the corresponding physical root sequence number u and du, the cyclic shift NCS, and the frequency domain data length LRA, the intermediate variables of the cyclic shift value Cv are calculated. These intermediate variables include: , , , .

6. The method for rapid generation of NR-5G restricted set PRACH sequences as described in claim 5, characterized in that, The formula for calculating the number of cyclic shift values ​​Cv is: , where w is the number of cyclic shift values ​​Cv corresponding to the logical root sequence number i, and A is the constraint set.

7. The method for rapid generation of NR-5G restricted set PRACH sequences as described in claim 1, characterized in that, Step S5 specifically involves filling the number of cyclic shift values ​​Cv and the value of each cyclic shift value Cv into the mapping table in step S1. By looking up the table, the results corresponding to the available logical root sequence number i are obtained, including the physical root sequence number u, du, the number of cyclic shift values ​​Cv, and the value of each cyclic shift value Cv.

8. The method for rapid generation of NR-5G restricted set PRACH sequences as described in claim 1, characterized in that, Step S6 is as follows: After the user equipment (UE) powers on and completes downlink synchronization, and after parsing the SIB1 message, when preparing to generate the PRACH sequence, it first looks up the corresponding physical root sequence number u and cyclic shift value Cv by using the PRACH logical root sequence number i, frequency domain data length LAR, cyclic shift NCS, and random number Preamble-Id value in SIB1. The base sequence is generated by using the physical root sequence number u, and then the base sequence is cyclically shifted according to the length of the cyclic shift value Cv to generate the PRACH transmission sequence.

9. A system for rapidly generating NR-5G restricted set PRACH sequences, used to implement the method for rapidly generating NR-5G restricted set PRACH sequences as described in any one of claims 1 to 8, characterized in that, The system includes a mapping table establishment module, a calculation module, a filling module, and a user equipment (UE). The mapping table establishment module is used to establish a mapping table from logical root sequence number i to the corresponding du of each root sequence. The calculation module is used to calculate the du corresponding to each root sequence, and determine whether du satisfies the relationship between cyclic shift (NCS) and frequency domain data length (LRA). Based on the determination result, it calculates the intermediate variable of cyclic shift value Cv, and based on the intermediate variable, calculates the number of available cyclic shift values ​​Cv corresponding to the current logical root sequence number i and the value of each cyclic shift value Cv. The filling module is used to fill the number of cyclic shift values ​​Cv and the value of each cyclic shift value Cv into the mapping table in step S1. After the user equipment (UE) is powered on, it generates a PRACH transmission sequence based on the physical root sequence number u and the value of the cyclic shift value Cv.

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