A frequency hopping method capable of avoiding co-frequency interference

Abstract

The present application relates to a kind of frequency hopping method of avoiding co-channel interference, comprising: step S1, in the available frequency band range, plan several carrier frequencies, and these carrier frequencies are divided into first carrier group and second carrier group;Wherein, the number of planned carrier frequency is twice the number of user to be scheduled;Step S2, with two adjacent time slots as a group, the frequency hopping value corresponding to time slot in each group is respectively mapped to the carrier frequency in the first carrier group and the carrier frequency in the second carrier group;Step S3, in each time slot, produce a frequency hopping value for each user to be scheduled in the time slot after a specified number of time slots in advance, obtain several to be adjusted frequency hopping value;Step S4, to the to-be-adjusted frequency hopping value obtained is adjusted, so that the to-be-adjusted frequency hopping value is not mutually different;Step S5, in the no time delay scene, according to the frequency hopping value adjusted in step S2, frequency hopping communication is carried out;In the time delay scene, according to the carrier frequency mapped to in step S4, frequency hopping communication is carried out.

Description

Technical Field

[0001] This invention relates to the field of wireless communication, and more specifically to a frequency hopping method that can avoid co-channel interference. Background Technology

[0002] In mobile communications, to prevent carrier frequencies from being tracked, intercepted, and interfered with by the enemy, the carrier frequencies of each cell need to be dynamically and randomly changed, i.e., frequency hopping communication. Frequency hopping communication has good anti-interference performance, security performance, and multiple access networking performance, and has been widely used in both military and civilian communications.

[0003] The performance of frequency hopping sequences has a decisive impact on the performance of frequency hopping communication systems. Currently, commonly used frequency hopping sequences include m-frequency hopping sequences constructed based on m-sequences, RS-frequency hopping sequences constructed based on RS codes, and chaotic frequency hopping sequences constructed based on chaotic maps. Among them, m-frequency hopping sequences and RS-frequency hopping sequences have better autocorrelation and cross-correlation, while chaotic frequency hopping sequences have slightly lower autocorrelation and cross-correlation.

[0004] However, the frequency hopping sequences obtained by current frequency hopping schemes cannot guarantee 100% orthogonality in either delay-free or delay-based scenarios, leading to co-channel interference between users and reducing communication performance. Specifically, this means there is co-channel interference within the same time slot (delay-free scenario) and co-channel interference between adjacent time slots (delay-based scenario).

[0005] Co-channel interference (without delay) occurs when different frequency hopping sequences have the same hopping value in the same time slot, causing frequency collisions and resulting in co-channel interference. For example, in chaotic frequency hopping sequences, it is theoretically impossible to guarantee that multiple chaotic frequency hopping sequences are orthogonal at all times. This means that at some point, there may be two or more users with the same carrier frequency, causing co-channel interference.

[0006] Co-channel interference in adjacent time slots (with delays) occurs when different frequency hopping sequences in adjacent time slots have the same frequency hopping value, causing frequency collisions and resulting in co-channel interference. This mainly happens during the user access phase, when users are not yet fully synchronized, and the arrival times of each user's signal at the base station differ, meaning there is a relative time delay between them. If the current frequency hopping value of a user is the same as the previous hop frequency hopping value of another delayed user, then co-channel interference exists between the delayed user and this user. Additionally, when multiple cells are networked on the same frequency, if the previous hop frequency hopping value from a neighboring cell is the same as the current hop frequency hopping value of this cell, it will also lead to inter-cell co-channel interference. Summary of the Invention

[0007] To address the problems in the prior art, the present invention provides a frequency hopping method that can avoid co-channel interference, thereby avoiding co-channel interference in both delay-free and delay-based scenarios.

[0008] This invention provides a frequency hopping method to avoid co-channel interference, comprising:

[0009] Step S1: Within the available frequency band, plan several carrier frequencies and divide these carrier frequencies into a first carrier frequency group and a second carrier frequency group; wherein the number of planned carrier frequencies is twice the number of users to be scheduled.

[0010] Step S2: Group two adjacent time slots together, and map the frequency hopping value corresponding to the time slot in each group to the carrier frequency in the first carrier frequency group and the carrier frequency in the second carrier frequency group respectively.

[0011] Step S3: In each time slot, generate a frequency hopping value in advance for each user to be scheduled in the time slot after a specified number of time slots, and obtain several frequency hopping values ​​to be adjusted.

[0012] Step S4: Adjust the obtained frequency hopping values ​​to be adjusted so that the frequency hopping values ​​to be adjusted are different from each other;

[0013] Step S5: In a no-latency scenario, frequency hopping communication is performed based on the frequency hopping value adjusted in step S4; in a time-latency scenario, frequency hopping communication is performed based on the carrier frequency mapped in step S2.

[0014] Step S1 includes: planning 2 within the available frequency band. Each of the different carrier frequencies , … ,Will , … Divided into the first carrier frequency group, , … It is divided into the second carrier frequency group.

[0015] Further, step S2 includes:

[0016] Step S21: Assign odd time slots to the first carrier frequency group and even time slots to the second carrier frequency group; wherein, odd time slots represent time slots with odd numbers and even time slots represent time slots with even numbers.

[0017] Step S22: Map the frequency hopping value corresponding to each odd time slot to a carrier frequency in the first carrier group, and map the frequency hopping value corresponding to each even time slot to a carrier frequency in the second carrier group to obtain the mapping relationship between the frequency hopping value and the carrier frequency;

[0018] In step S23, the base station merges the mapping relationship obtained in step S22 into the resource scheduling information and sends the resource scheduling information to the user to be scheduled.

[0019] Further, step S3 includes: in the time slot - Generate a time slot for each of the users to be scheduled. time There are 1 frequency hopping value, and each frequency hopping value belongs to the candidate frequency hopping value set. ,in, For a specified number of time slots, The number of time slots for a specified number of time slots. This represents the number of users to be scheduled.

[0020] Further, step S4 includes:

[0021] Step S41, in time slot - Analysis of the above If there are identical frequency hopping values ​​among the frequency hopping values, proceed to step S5 if no, and proceed to step S42 if yes.

[0022] Step S42: Adjust the same frequency hopping value to an unused frequency hopping value in the candidate frequency hopping value set, so that each frequency hopping value in the candidate frequency hopping value set is used once;

[0023] In step S43, the base station merges the adjusted frequency hopping value into the resource scheduling information and sends the resource scheduling information to the user to be scheduled, proceeding to step S5.

[0024] The frequency hopping method provided by this invention, which avoids co-channel interference, has the following beneficial effects:

[0025] 1) By utilizing the "advance scheduling" time window, the same frequency hopping value that may exist in future time slots is adjusted to ensure that the frequency hopping value of each user is different at the same time, thereby ensuring that the carrier frequency of each user is different and completely avoiding co-channel interference in the same time slot;

[0026] 2) By planning two sets of orthogonal carrier frequencies and using different carrier frequency groups in adjacent time slots, even if the frequency hopping value of the delayed user is the same as that of the current user, the carrier frequencies of the delayed user and the current user are orthogonal because they are mapped to different carrier frequencies, thus avoiding co-channel interference between adjacent time slots. Attached Figure Description

[0027] Figure 1 This is a flowchart of a frequency hopping method according to the present invention that can avoid co-channel interference.

[0028] Figure 2 This is a diagram illustrating advance scheduling.

[0029] Figure 3This is a schematic diagram illustrating the application scenario of the present invention. Detailed Implementation

[0030] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0031] The frequency hopping method to avoid co-channel interference provided by this invention has the following core idea: For co-channel interference in the same time slot, "advance scheduling" is used, that is, the base station adjusts the same frequency hopping value several time slots in advance, and then sends the adjusted frequency hopping value to the user through signaling to ensure that the frequency hopping value of each user in the same time slot is different, thereby avoiding co-channel interference in the same time slot; For co-channel interference between adjacent time slots, "orthogonal carrier groups" are used, that is, two groups of orthogonal carriers are planned, and different carrier groups are used for adjacent time slots, so as to avoid co-channel interference between adjacent time slots.

[0032] Specifically, such as Figure 1 As shown, the frequency hopping method to avoid co-channel interference provided by the present invention includes the following steps:

[0033] Step S1: Within the available frequency band, plan several carrier frequencies based on the number of users to be scheduled, and divide these carrier frequencies into a first carrier frequency group and a second carrier frequency group. The number of planned carrier frequencies is equal to the number of users to be scheduled. Twice as much.

[0034] Specifically, within the available frequency band, plan 2 Each of the different carrier frequencies , … , This represents the number of users to be scheduled, divided into two groups of orthogonal carrier frequencies as shown in Table 1:

[0035] Table 1 Orthogonal Carrier Frequency Allocation Table

[0036]

[0037] The above 2 carrier frequency , … It can be random, or it can be arranged in ascending order or descending order. In this embodiment, , … Arranging the carrier frequencies from smallest to largest or from largest to smallest, according to Table 1, maximizes the carrier frequency spacing between any two adjacent time slots and minimizes adjacent channel leakage. It should be understood that in other embodiments, the carrier frequency... , … It can also be other sorting methods or other grouping methods.

[0038] In scenarios with time delays, when the delay exceeds one time slot, the interference power reaching the interfered base station or user is negligible due to significant path loss; the interference is far less than the noise floor. Therefore, delays exceeding one time slot can be disregarded. For example, assuming one time slot lasts 0.5 milliseconds, the corresponding propagation distance is 150 km. The cell radius should be less than 150 km, so the delay for users within the same cell reaching the base station must be less than one time slot. Furthermore, even if the cell radius is greater than 150 km, the delay for users at the cell edge might be greater than one time slot, say two time slots. In this case, the propagation distance is 300 km, the free path loss is nearly 200 dBm, and the interference power reaching the interfered base station is approximately -160 dBm, far less than the noise floor. Therefore, interference power with delays greater than or equal to two time slots can be ignored.

[0039] Therefore, in step S2, two adjacent time slots are grouped together, and all frequency hopping values ​​corresponding to the two time slots in each group are mapped to the carrier frequencies in the first carrier frequency group and the carrier frequencies in the second carrier frequency group, respectively.

[0040] Specifically, step S2 includes:

[0041] Step S21: Odd-numbered time slots are assigned to the first carrier group, and even-numbered time slots are assigned to the second carrier group. This step ensures that adjacent time slots use different carrier groups, as shown in Table 2.

[0042] Table 2 Carrier groups used in adjacent time slots

[0043]

[0044] It should be noted that, in this embodiment, even time slots can also be mapped to the first carrier frequency group, and odd time slots can be mapped to the second carrier frequency group.

[0045] Step S22: Map the frequency hopping value corresponding to each odd time slot to a carrier frequency in the first carrier group, and map the frequency hopping value corresponding to each even time slot to a carrier frequency in the second carrier group to obtain the mapping relationship between the frequency hopping value and the carrier frequency.

[0046] In this embodiment, the mapping relationship between the frequency hopping value and the carrier frequency is shown in Table 3:

[0047] Table 3. Frequency Hopping Value to Carrier Frequency Mapping Table

[0048]

[0049] It should be noted that in other embodiments, the frequency hopping value and the carrier frequency can also adopt other mapping methods, as long as each frequency hopping value corresponds to one carrier frequency.

[0050] In step S23, the base station merges the mapping relationship obtained in step S22 into the resource scheduling information and sends the resource scheduling information to the user to be scheduled.

[0051] Steps S1 and S2 above can ensure that in time-delay scenarios, even if the frequency hopping values ​​of adjacent time slots are the same, the carrier frequencies between delayed users and non-delayed users are still orthogonal because they are mapped to different carrier frequencies, thereby avoiding co-channel interference between adjacent time slots.

[0052] As can be seen from Table 3, different frequency hopping values ​​correspond to different carrier frequencies. Even with the same frequency hopping value, delaying by one time slot results in different mapped carrier frequencies because the delayed time slot and the current time slot are different in terms of odd or even numbers. This can avoid co-channel interference in the same time slot and co-channel interference in adjacent time slots.

[0053] Step S3: In each time slot, generate a frequency hopping value in advance for each user to be scheduled in the time slot one time slot after a specified number of time slots in that time slot, and obtain several frequency hopping values ​​to be adjusted.

[0054] like Figure 2 As shown, For a future time slot, the base station is prepared in advance. Schedule future time slots in a time slot Communication users (specified number of time slots) (time slots), that is, the base station in a time slot - Generate the frequency hopping value for time slot T for each scheduled user. Set a common... If there are users to be scheduled, then... There are 1 frequency hopping value, and each frequency hopping value belongs to the candidate frequency hopping value set. .

[0055] Step S4 involves adjusting the obtained frequency hopping values ​​to ensure that these values ​​are distinct from each other. Specifically, step S4 includes:

[0056] Step S41, in time slot - Analysis of the above If there are identical frequency hopping values ​​among the frequency hopping values, proceed to step S5 if no, and proceed to step S42 if yes.

[0057] Step S42: Adjust the same frequency hopping value to an unused frequency hopping value in the candidate frequency hopping value set, so that the frequency hopping value in the candidate frequency hopping value set is used once, thereby ensuring that the frequency hopping values ​​of each user in the same time slot are different and avoiding co-channel interference in the same time slot.

[0058] For example, suppose there are 5 frequency-hopping users, and 5 candidate frequency-hopping values: 1, 2, 3, 4, and 5. Assume that in the time slot... - The frequency hopping values ​​generated for these 5 users are 1, 3, 5, 2, and 2, respectively. It can be seen that the 4th and 5th users have the same frequency hopping value of 2. At this point, the frequency hopping value of the 5th user can be adjusted to the unused frequency hopping value of 4. After the adjustment, the frequency hopping values ​​for the 5 users are 1, 3, 5, 2, and 4, making each user's frequency hopping value different from the others.

[0059] In step S43, the base station merges the adjusted frequency hopping value into the resource scheduling information and sends the resource scheduling information to the user to be scheduled, proceeding to step S5.

[0060] Step S5: In a no-delay scenario, frequency hopping communication is performed based on the frequency hopping value adjusted in step S4; in a delayed scenario, frequency hopping communication is performed based on the carrier frequency mapped in step S2.

[0061] Specifically, examples of the application of this invention in wireless mobile communication networks include... Figure 3 As shown, this invention operates simultaneously on both the terminal side (i.e., the user side) and the base station side. The base station is in advance... Each time slot is a future time slot. Each scheduling user generates a frequency hopping value and analyzes whether there are duplicate frequency hopping values. If so, the duplicate frequency hopping value is adjusted to a different unused frequency hopping value, and the adjusted frequency hopping value is sent in subsequent resource scheduling signaling. The terminal also generates future time slots based on the frequency hopping parameters (which are sent to the user via SIB messages during initial access). If no new frequency hopping value is received in the received resource scheduling signaling, then in the time slot... Use your own generated frequency hopping value; otherwise, use the time slot. Use the frequency hopping value sent by the base station.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A frequency hopping method that avoids co-channel interference, characterized in that, include: Step S1: Within the available frequency band, plan several carrier frequencies and divide these carrier frequencies into a first carrier frequency group and a second carrier frequency group; wherein the number of planned carrier frequencies is twice the number of users to be scheduled. Step S2: Group two adjacent time slots together, and map the frequency hopping value corresponding to the time slot in each group to the carrier frequency in the first carrier frequency group and the carrier frequency in the second carrier frequency group respectively. Step S3: In each time slot, generate a frequency hopping value in advance for each user to be scheduled in the time slot after a specified number of time slots, and obtain several frequency hopping values ​​to be adjusted. Step S4: Adjust the obtained frequency hopping values ​​to be adjusted so that the frequency hopping values ​​to be adjusted are different from each other; Step S5: In a no-latency scenario, frequency hopping communication is performed based on the frequency hopping value adjusted in step S4; in a time-latency scenario, frequency hopping communication is performed based on the carrier frequency mapped in step S2.

2. The frequency hopping method for avoiding co-channel interference according to claim 1, characterized in that, Step S1 includes: planning 2 within the available frequency band. Each of the different carrier frequencies , … ,Will , … Divided into the first carrier frequency group, , … It is divided into the second carrier frequency group.

3. The frequency hopping method for avoiding co-channel interference according to claim 2, characterized in that, Step S2 includes: Step S21: Assign odd time slots to the first carrier frequency group and even time slots to the second carrier frequency group; wherein, odd time slots represent time slots with odd numbers and even time slots represent time slots with even numbers. Step S22: Map the frequency hopping value corresponding to each odd time slot to a carrier frequency in the first carrier group, and map the frequency hopping value corresponding to each even time slot to a carrier frequency in the second carrier group to obtain the mapping relationship between the frequency hopping value and the carrier frequency; In step S23, the base station merges the mapping relationship obtained in step S22 into the resource scheduling information and sends the resource scheduling information to the user to be scheduled.

4. The frequency hopping method for avoiding co-channel interference according to claim 1, characterized in that, Step S3 includes: in the time slot - Generate a time slot for each of the users to be scheduled. The frequency hopping value at time, each frequency hopping value belongs to the candidate frequency hopping value set. ,in, For a specified number of time slots, The number of time slots for a specified number of time slots. This represents the number of users to be scheduled.

5. The frequency hopping method for avoiding co-channel interference according to claim 4, characterized in that, Step S4 includes: Step S41, in time slot - Analysis of the above If there are identical frequency hopping values ​​among the frequency hopping values, proceed to step S5 if no, and proceed to step S42 if yes. Step S42: Adjust the same frequency hopping value to an unused frequency hopping value in the candidate frequency hopping value set, so that each frequency hopping value in the candidate frequency hopping value set is used once; In step S43, the base station merges the adjusted frequency hopping value into the resource scheduling information and sends the resource scheduling information to the user to be scheduled, proceeding to step S5.

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