UAV communication system and communication method

Abstract

The present invention discloses a UAV communication system, including a UAV end, a ground end, a communication link sending module and a communication link receiving module. The communication link sending module is used to carry TB on channel time-frequency resources and send it to the communication link receiving module according to a preset resource allocation scheme; the communication link receiving module is used to distinguish different TBs and different copies of TBs, and screen according to two TB indication fields in the correctly received TBs to obtain valid data contained in the TBs. The present invention carries the transmission blocks to be repeatedly sent on the redundant channel resources of the UAV communication link, and sends copies of the same TB on channel resources with different frequencies and / or different times to obtain the effect of additional frequency diversity gain and / or time diversity gain, compensating for the adverse effects of the frequency selective fading and / or time selective fading characteristics of the wireless channel on the correct reception of the signal, so as to achieve the purpose of making full use of the available channel resources to improve the quality and reliability of link data transmission.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned aerial vehicle communication, and in particular relates to a unmanned aerial vehicle communication system and a communication method. Background Art

[0002] Real-time data transmission is required between unmanned aerial vehicles (UAVs) and ground terminals (remote controllers or ground control stations, etc.). As the application scenarios of UAVs continue to expand, higher and higher requirements are also placed on the effectiveness and reliability of real-time communication. The quality of the UAV communication link plays a crucial role in this. The link includes two-way data communication: one is the uplink communication link for the UAV to receive control command information sent by the ground terminal, and the other is the downlink communication link for the ground terminal to receive real-time collected data or captured images and other information sent by the UAV.

[0003] Current communication systems generally change the data bandwidth of the system by adaptively adjusting the modulation and coding strategy (MCS) to match the average transmission rate of valid data within a period of time. This method can achieve the adaptation between the total data bandwidth and the effective data rate to a certain extent, but it still cannot guarantee that all, or as many, of the available channel resources are utilized, especially for the uplink, which usually has a small amount of control instruction data and a low utilization rate of available channel resources, but usually has high requirements for the quality and reliability of reception.

[0004] To this end, we propose a UAV communication system and communication method to solve the problems existing in the existing technology, improve the reliability of controlling the UAV, and reduce the risk of loss of connection. Summary of the invention

[0005] The object of the present invention is to provide a UAV communication system and a communication method to solve the problem raised in the above background technology that the utilization rate of available channel resources in the prior art is low, but the requirements for reception quality and reliability are generally high.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a UAV communication system, comprising a UAV terminal, a ground terminal, a communication link sending module and a communication link receiving module, wherein the communication link sending module comprises an uplink communication link sending module and a downlink communication link sending module; the communication link receiving module comprises an uplink communication link receiving module and a downlink communication link receiving module; the uplink communication link sending module communicates and connects with the uplink communication link receiving module to establish an uplink communication link, and the downlink communication link sending module communicates and connects with the downlink communication link receiving module to establish a downlink communication link;

[0007] The ground terminal sends control command information to the drone terminal via an uplink communication link;

[0008] The UAV sends the real-time collected data and captured image information to the ground terminal via a downlink communication link;

[0009] The communication link sending module is used to send the TB carried on the channel time-frequency resources to the communication link receiving module according to a preset resource allocation scheme;

[0010] The communication link receiving module is used to distinguish different TBs and different copies of TBs, and to perform screening according to two TB indication fields in the correctly received TBs to obtain valid data contained in the TBs.

[0011] The present invention also provides a UAV communication method, comprising the following steps:

[0012] S1. The communication link sending module sends TB on the channel time-frequency resources according to the preset resource allocation scheme, where TB is the smallest unit of valid data to be sent, and one TB contains a fixed amount of valid data and occupies a fixed frequency domain length B and time domain length T on the time-frequency resources;

[0013] S2. When redundant available channel resources are found, the communication link sending module will select a suitable original TB to generate a corresponding replica TB to be carried on the channel resource. The replica TB and the corresponding original TB contain the same valid data. The TB containing more important valid data has a higher priority, and the number of TB copies allowed to be generated is also more accordingly.

[0014] S3. In order to enable the receiver to distinguish different TBs and different copies of TBs, two TB indication fields will be added to the TB. 1 and F 2 , where F 1 The field value is used to distinguish different TBs. 2 The field value is used to distinguish different copies of the same TB.

[0015] Furthermore, the valid data in S2 includes all types of data, among which the more important ones are control instruction data and key information collection data.

[0016] Furthermore, the number of copies of the same TB in S3 cannot exceed a preset upper limit n. max The time domain difference between the original TB and the replica TB in the channel resource in S3 has an upper limit value Δt max ,The purpose of setting the upper limit is to prevent aliasing between different TBs and meet the ,requirements of real-time reception.

[0017] Furthermore, the original TB and the copy TB in S3 are allocated at different relative positions on the available channel resources, which are divided into three types: simultaneous different frequencies, different times and the same frequency, and different times and different frequencies.

[0018] Furthermore, the simultaneous frequency difference means that the original TB and the replica TB are allocated to the same position in the time domain on the available channel resources but different positions in the frequency domain.

[0019] Furthermore, the different-time and same-frequency allocation means that the original TB and the copy TB are allocated different positions in the time domain on the available channel resources but the same positions in the frequency domain.

[0020] Furthermore, the different time and frequency means that the original TB and the replica TB are allocated different positions in the time domain and frequency domain on the available channel resources.

[0021] Furthermore, the signal of the communication link sending module reaches the communication link receiving module through the wireless fading channel. Due to the influence of system deviation and channel noise and interference, some TBs cannot be demodulated and received correctly. The communication link receiving module will screen according to the two newly added fields in the correctly received TB, that is, the same TB only retains the valid data contained in one copy of the TB, so as to avoid the duplication of the output valid data.

[0022] Compared with the prior art, the present invention has the following advantages: the present invention carries the transmission blocks to be repeatedly sent on the redundant channel resources of the UAV communication link, and sends copies of the same TB on different frequency and / or time channel resources to obtain additional frequency diversity gain and / or time diversity gain effects, thereby compensating for the adverse effects of the frequency selective fading and / or time selective fading characteristics of the wireless channel on the correct reception of the signal, thereby achieving the purpose of making full use of the available channel resources to improve the quality and reliability of link data transmission, improving the reliability of controlling the UAV and reducing the risk of the UAV losing contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the allocation diagram of simultaneous frequency difference in the present invention;

[0024] Figure 2 It is the distribution diagram of different time and same frequency in the present invention;

[0025] Figure 3 It is the distribution diagram of different time and frequency in the present invention;

[0026] Figure 4 It is the original distribution TB distribution diagram in Example 1 of the present invention;

[0027] Figure 5 This is a TB distribution diagram of simultaneous and different frequencies in Example 1 of the present invention;

[0028] Figure 6 This is a TB distribution diagram of different time and frequency in Example 2 of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying 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, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] The present invention provides a UAV communication system, comprising a UAV terminal, a ground terminal, a communication link sending module and a communication link receiving module, wherein the communication link sending module comprises an uplink communication link sending module and a downlink communication link sending module; the communication link receiving module comprises an uplink communication link receiving module and a downlink communication link receiving module; the uplink communication link sending module is connected to the uplink communication link receiving module for communication to establish an uplink communication link, and the downlink communication link sending module is connected to the downlink communication link receiving module for communication to establish a downlink communication link;

[0032] The ground terminal sends control command information to the drone terminal via an uplink communication link;

[0033] The UAV sends the real-time collected data and captured image information to the ground terminal via a downlink communication link;

[0034] The communication link sending module is used to send the TB carried on the channel time-frequency resources to the communication link receiving module according to a preset resource allocation scheme;

[0035] The communication link receiving module is used to distinguish different TBs and different copies of TBs, and to perform screening according to two TB indication fields in the correctly received TBs to obtain valid data contained in the TBs.

[0036] In addition, an embodiment of the present invention further provides a drone communication method, comprising the following steps:

[0037] S1. The communication link sending module sends TB on the channel time-frequency resources according to the preset resource allocation scheme, where TB is the smallest unit of valid data to be sent, and one TB contains a fixed amount of valid data and occupies a fixed frequency domain length B and time domain length T on the time-frequency resources;

[0038] S2. When redundant available channel resources are found, the communication link sending module will select a suitable original TB to generate a corresponding copy TB to be carried on the channel resource. The copy TB and the corresponding original TB contain the same valid data. The TB containing more important valid data has a higher priority, and the number of TB copies allowed to be generated is also more. The valid data includes all types of data, among which the more important ones are control instruction data and key information collection data.

[0039] S3. In order to enable the receiving end to distinguish different TBs and different copies of TBs, two fields, F1 and F2, are added to the TB. The F1 field value is used to distinguish different TBs, and the F2 field value is used to distinguish different copies of the same TB. The time domain difference between the original TB and the copy TB on the channel resources has an upper limit. The purpose of setting the upper limit is to prevent aliasing between different TBs and meet the requirements of real-time reception.

[0040] like Figure 1 As shown, Figure 1 The original TB and the duplicate TB are allocated in the same time domain position on the available channel resources but different frequency domain positions. The frequency domain positions can be continuous or discontinuous. This allocation method can obtain frequency diversity gain and obtain additional resistance to frequency selective fading.

[0041] like Figure 2 As shown, Figure 2 The original TB and the duplicate TB are allocated at different positions in the time domain on the available channel resources but at the same frequency domain. The time domain positions can be continuous or discontinuous. This allocation method can obtain time diversity gain and additional resistance to time selective fading.

[0042] like Figure 3 As shown, Figure 3 The original TB and the duplicate TB are allocated at different positions in the time domain and frequency domain on the available channel resources. This allocation method can obtain both time diversity gain and frequency diversity gain, and can obtain additional resistance to time selective and frequency selective fading.

[0043] When the number of copies is more than one, the relative positions of the original TB and the multiple copy TBs allocated on the available channel resources can be a combination of the above three types of methods.

[0044] The signal from the communication link sending module reaches the communication link receiving module through the wireless fading channel. Due to the influence of system deviation, channel noise and interference, some TBs cannot be demodulated and received correctly. The communication link receiving module will screen according to the two newly added fields in the correctly received TBs, that is, the same TB only retains one copy of the valid data contained in the TB to avoid the duplication of the output valid data.

[0045] Assume that the frequency width of the available channel resources of the current UAV communication link is 2B, and the time length is unlimited. Only observe the distribution of the original TB on the available channel resources in a short period of time, such as Figure 4 As shown in the figure, TB1, TB2 and TB3 all contain different valid data. It can be found that the original TB only occupies half of the channel resources, and the other half does not carry any useful data. When the resource allocation method of simultaneous frequency is adopted, the transmitter will determine whether there is redundancy in the channel resources at a certain moment. If so, the original TB at the same moment will be generated into a copy TB and carried on the redundant channel resources at the same moment, as shown in the figure. Figure 5 For example, TB1(0) is the original TB, and TB1(1) is the corresponding copy TB. In the two newly added fields of TB, the F 1 The field value is 1, and the F of TB2(0) and TB2(1) 1 The field value is 2, F of TB3(0) and TB3(1) 1 The field value is 3, and the F 2 The field value is 0, and the F of TB1(1), TB2(1), and TB3(1) 2 The field value is 1, and the receiving end will filter the valid data based on the two newly added fields in the correctly received TB.

[0046] Example 2

[0047] In this embodiment, a resource allocation method of different time and frequency is used for explanation. The background assumption of the UAV communication link is as in Embodiment 1 and Figure 4 As shown in FIG. 1 , when the resource allocation method of different time and frequency is adopted, the transmitting end will determine whether there is redundancy in the channel resources at a certain moment. If so, the original TB with different frequency positions of the redundant channel resources at the previous moment and the current moment will be generated into a copy TB, which is carried on the redundant channel resources at the current moment, such as Figure 6 As shown, for example, TB1(0) is the original TB, and TB1(1) is the corresponding copy TB. In the two newly added fields of TB, the F 1 The field value is 1, and the F of TB2(0) and TB2(1) 1The field value is 2, F of TB3(0) and TB3(1) 1 The field value is 3, and the F 2 The field value is 0, and the F of TB1(1), TB2(1), and TB3(1) 2 The field value is 1, and the receiving end will filter the valid data based on the two newly added fields in the correctly received TB.

[0048] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A UAV communication method, used in a UAV communication system, characterized in that: The UAV communication system includes a UAV end, a ground end, a communication link sending module and a communication link receiving module, wherein the communication link sending module includes an uplink communication link sending module and a downlink communication link sending module; the communication link receiving module includes an uplink communication link receiving module and a downlink communication link receiving module; the uplink communication link sending module communicates and connects with the uplink communication link receiving module to establish an uplink communication link, and the downlink communication link sending module communicates and connects with the downlink communication link receiving module to establish a downlink communication link; the ground end sends control command information to the UAV end through the uplink communication link; the UAV end sends real-time collected data and captured image information to the ground end through the downlink communication link; The communication link sending module is used to carry the TB on the channel time-frequency resources and send it to the communication link receiving module according to the preset resource allocation scheme; the communication link receiving module is used to distinguish different TBs and different copies of TBs, and filter according to the two TB indication fields in the correctly received TB to obtain the valid data contained in the TB; The method comprises the following steps: S1. The communication link sending module sends TB on the channel time-frequency resources according to the preset resource allocation scheme, where TB is the smallest unit of valid data to be sent, and one TB contains a fixed amount of valid data and occupies a fixed frequency domain length B and time domain length T on the time-frequency resources; S2. When redundant available channel resources are found, the communication link sending module will select a suitable original TB to generate a corresponding replica TB to be carried on the channel resource. The replica TB and the corresponding original TB contain the same valid data. The TB containing more important valid data has a higher priority, and the number of TB copies allowed to be generated is also more accordingly. S3. In order to enable the receiving end to distinguish different TBs and different copies of TBs, two TB indication fields, F1 and F2, will be added to the TB. The F1 field value is used to distinguish different TBs, and the F2 field value is used to distinguish different copies of the same TB. The number of copies of the same TB cannot exceed the preset upper limit value n. max The time domain difference between the original TB and the replica TB in the channel resource in S3 has an upper limit value Δt max ,The purpose of setting the upper limit is to prevent aliasing between different TBs and meet the ,requirements of real-time reception.

2. A drone communication method according to claim 1, characterized in that: The effective data in S2 includes all types of data, among which the more important ones are control instruction data and key information collection data.

3. The UAV communication method according to claim 1, characterized in that: The original TB and the replica TB in S3 are allocated at different relative positions on the available channel resources, which are divided into three types: simultaneous different frequencies, different times and the same frequency, and different times and different frequencies.

4. A UAV communication method according to claim 3, characterized in that: The simultaneous frequency difference means that the original TB and the replica TB are allocated to the same position in the time domain on the available channel resources but different positions in the frequency domain.

5. A UAV communication method according to claim 4, characterized in that: The different-time-same-frequency means that the original TB and the copy TB are allocated to different positions in the time domain on the available channel resources but the same positions in the frequency domain.

6. A UAV communication method according to claim 5, characterized in that: The different time and frequency means that the original TB and the copy TB are allocated different positions in the time domain and frequency domain on the available channel resources.

7. The UAV communication method according to claim 1, characterized in that: The signal of the communication link sending module reaches the communication link receiving module through the wireless fading channel. Due to the influence of system deviation and channel noise and interference, some TBs cannot be demodulated and received correctly. The communication link receiving module will screen according to the two newly added fields in the correctly received TB, that is, the same TB only retains the valid data contained in one TB to avoid the duplication of the output valid data.

Images