KR102625778B1 - ARQ feedback method when ARQ is used in Half duplex mode in Proximity-1 system - Google Patents

Abstract

The present invention can provide a method of transmitting data using ARQ in half duplex mode of short-range wireless communication for space exploration. At this time, the data transmission method includes the following steps: determining whether there is data to transmit after switching to the sender in the half duplex switching preparation stage; determining whether there are transmission errors in all frames received in the half duplex switching preparation stage; It may include the steps of switching from the receiver to the sender and setting the length of the Carrier Only Duration section to be transmitted, switching to the sender and transmitting a signal during the Carrier Only Duration section, and switching back to the receiver to prepare for frame reception.

Description

ARQ response method when ARQ is used in Half duplex mode in Proximity-1 system {ARQ feedback method when ARQ is used in Half duplex mode in Proximity-1 system}

The present invention relates to a technology for reducing time and power consumption caused by transmission and reception switching for ARQ feedback transmission when Proximity-1 operates in half duplex mode and uses ARQ (Automatic ReQuest for repetition).

The Proximity-1 system used in space exploration is a CCSDS standard that includes a data link layer and a physical layer and can be used for short-range wireless communication between two Spacecraft ranging from 1m to 100,000km. Proximity-1's data link layer can support full duplex, half duplex, and simplex modes. At this time, Simplex mode may be a method of transmitting data in one direction. In addition, half duplex is a half-duplex transmission method that allows data to be transmitted in both directions from each entity, but when one side transmits data, the other side cannot transmit data. In addition, the full duplex method is a full-duplex transmission method, which allows each entity to transmit data in both directions simultaneously.

At this time, for data transmission, Expedited service for fast transmission and Sequential controlled service for reliable transmission are provided. While the Expedited service does not retransmit, the Sequential controlled service based on Go-Back-N ARQ performs retransmission to ensure that frames are delivered in order without errors, duplication, or omission.

In a system using Go-Back-N ARQ, the sender can transmit N frames before receiving ARQ feedback and receives a cumulative response from the receiver. If an error response (Negative Acknowledge, NACK) is received or the timer is completed, the frame is retransmitted from the last frame for which normal reception was confirmed through ARQ feedback. Data transmission in space exploration involves sending a large amount of exploration data from an exploration vehicle, including a Rover, to a Lander or orbiter, while occasionally sending short commands to the exploration vehicle.

Therefore, half duplex mode is mainly used to save energy for probes with limited power resources. However, transmission/reception conversion in Proximity-1's half duplex mode consists of token transmission and synchronization signal transmission processes, and a lot of time and energy is consumed for one transmission/reception conversion. Therefore, when data is transmitted using Go-Back-N ARQ in half duplex mode, if transmission and reception are switched only to transmit an ACK frame when there is no data to send from the receiving side other than ARQ feedback, this leads to a lot of time and energy wastage. Therefore, an ARQ feedback method that can save power and time is needed.

The purpose of the present invention is to provide an ARQ response method when using ARQ in half duplex mode of the Proximity-1 system.

Additionally, the purpose of the present invention is to provide an ARQ feedback method that saves power and time when using ARQ in the half duplex mode of the Proximty-1 system.

According to an embodiment of the present invention, a method of transmitting data using ARQ in half duplex mode of short-range wireless communication for space exploration can be provided. At this time, the data transmission method includes the following steps: determining whether there is data to transmit after switching to the sender in the half duplex switching preparation stage; determining whether there are transmission errors in all frames received in the half duplex switching preparation stage; It may include the steps of switching from the receiver to the sender and setting the length of the Carrier Only Duration section to be transmitted, switching to the sender and transmitting a signal during the Carrier Only Duration section, and switching back to the receiver to prepare for frame reception. At this time, if the receiver switches to the sender and there is no data to transmit, and there are no transmission errors in all received frames, the length of the Carrier Only Duration section is set to the length for ARQ feedback that is longer than the basic Carrier Only Duration, and the receiver If ARQ feedback through the Carrier Only Duration section length is used n times in succession, the feedback can be transmitted through normal half-duplex transmission/reception switching.

The features briefly summarized above with respect to the present invention are merely exemplary aspects of the detailed description of the present disclosure and are not intended to limit the scope of the present disclosure.

According to the present invention, an ARQ response method can be provided when using ARQ in the half duplex mode of the Proximity-1 system.

Additionally, the purpose of the present invention is to provide an ARQ feedback method that saves power and time when using ARQ in the half duplex mode of the Proximty-1 system.

In addition, according to the present invention, when two Spacecraft transmit data using ARQ in half duplex mode through short-range wireless communication for space exploration, it provides a method of saving time and energy by performing ARQ responses more efficiently. You can.

The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below. will be.

Figure 1 is a diagram showing a method of switching from transmission to reception in half duplex mode of Proximity-1 according to the present disclosure.
Figure 2 is a diagram showing a method of switching reception to transmission in half duplex mode of Proximity-1 according to the present disclosure.
Figure 3 is a diagram showing the process of sending and receiving data and an ACK frame through a transmission/reception switching procedure using Go-Back-N ARQ in half duplex mode according to the present disclosure.
Figure 4 is a diagram showing a method of processing an ARQ response according to the present disclosure.
Figure 5 is a diagram showing a method of transmitting ARQ feedback according to the present disclosure.
Figure 6 is a diagram showing a device according to the present disclosure.

Hereinafter, with reference to the attached drawings, embodiments of the present disclosure will be described in detail so that those skilled in the art can easily practice them. However, the present disclosure may be implemented in many different forms and is not limited to the embodiments described herein.

In describing embodiments of the present disclosure, if it is determined that detailed descriptions of known configurations or functions may obscure the gist of the present disclosure, detailed descriptions thereof will be omitted. In addition, in the drawings, parts that are not related to the description of the present disclosure are omitted, and similar parts are given similar reference numerals.

In the present disclosure, when a component is said to be “connected,” “coupled,” or “connected” to another component, this is not only a direct connection relationship, but also an indirect connection relationship in which another component exists in between. It may also be included. In addition, when a component is said to "include" or "have" another component, this does not mean excluding the other component, but may further include another component, unless specifically stated to the contrary. .

In the present disclosure, terms such as first, second, etc. are used only for the purpose of distinguishing one component from other components, and do not limit the order or importance of components unless specifically mentioned. Therefore, within the scope of the present disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, the second component in one embodiment may be referred to as a first component in another embodiment. It may also be called.

In the present disclosure, distinct components are intended to clearly explain each feature, and do not necessarily mean that the components are separated. That is, a plurality of components may be integrated to form one hardware or software unit, or one component may be distributed to form a plurality of hardware or software units. Accordingly, even if not specifically mentioned, such integrated or distributed embodiments are also included in the scope of the present disclosure.

In the present disclosure, components described in various embodiments do not necessarily mean essential components, and some may be optional components. Accordingly, embodiments consisting of a subset of the elements described in one embodiment are also included in the scope of the present disclosure. Additionally, embodiments that include other components in addition to the components described in the various embodiments are also included in the scope of the present disclosure.

In the following, the configuration of the invention is explained as an example in which Lander and Rover communicate through Proximity-1, but it is not limited to this. In the case of the present invention, it can be used in all cases of data communication between a communication device and a communication device including Spacecraft using the Proximity-1 standard or short-range wireless communication for space exploration. Additionally, it can be equally applied to other systems and is not limited to the above-described embodiment.

The present invention seeks to provide a method to reduce time and power waste that occurs in the process of exchanging ARQ feedback information when transmitting data using Go-Back-N ARQ in Proximity-1 half duplex mode. At this time, as an example, a situation in which the Rover transmits exploration data to the Lander using Go-Back-N ARQ in half duplex mode is taken as an example. However, as described above, it is not limited to this and can be equally applied to cases where operations are performed as a transmitting end and a receiving end.

Since the response of the existing ARQ is delivered through an ACK frame, when operating in half duplex mode, the sender is required to switch operations to the receiver and the receiver to the sender in order to exchange the ACK frame. In other words, operation switching may be necessary considering the half duplex transmission method. However, if there is no transmission data other than ARQ feedback, another transmission/reception transition may be necessary to return to the original state. The present invention proposes a method of transmitting ARQ feedback using a carrier signal instead of an ACK frame when no transmission error occurs and when the receiver has no data to transmit other than ARQ feedback.

As an example, ARQ feedback transmission is performed while the transmission/reception conversion process is performed, and after the ARQ feedback transmission, the transmission/reception conversion process is stopped and the process may return to the original state. Therefore, as in the existing method, there is no need for another transmission/reception switching process to return to the original state after transmitting the ACK frame, so only one transmission/reception switching attempt to exchange the carrier can be performed, rather than the entire transmission/reception switching process.

Figures 1 and 2 show the process of switching from transmission to reception in half duplex mode of Proximity-1. Specifically, Figure 1 shows the Rover's switching operation from transmission to reception. Additionally, Figure 2 shows Lander's reception to transmission switching operation. At this time, as shown in Figure 1, the transmission/reception switching process begins with the occurrence of Send Duration Timeout or Receive Duration Timeout and goes through several steps such as token delivery, transmission/reception mode switching, and frequency and frame synchronization.

Referring to Figure 1, the specific procedure for switching from Rover operating in transmission mode to reception mode is as follows. Transmit data in data transmission state. (S101) Next, Send Duration Timeout occurs. (S102) At this time, if the Send Duration Timeout has not occurred, data transmission can be performed again, and if it has occurred, you can move to “S103”. Next, an SPDU frame is created and a token is transmitted to notify Lander of the transmission/reception switch. (S103) Next, send Tail Idle to finalize transmission and end data transmission. (S104) Next, switch from transmission to reception mode. (S105) Next, in the Wait for Carrier state, wait for the carrier signal for frequency synchronization from the Lander during the Receive Duration. (S106) At this time, if you receive the carrier signal, you can move to step “S107”. In other words, when Carrier Lock = true, it continues to wait for normal frame reception until the Carrier signal is cut off in the Awaiting First Frame state (Carrier Lock = false). (S107)

Next, when a normal frame is received, the data reception state is established and data can be received. (S108)

However, steps S106 and S107 during the transition from transmission to reception mode described above may be processes for performing frequency synchronization and frame synchronization, respectively. As long as Carrier Lock is ‘true’, frame synchronization continues to be sought in the Awaiting First Frame state, but if Carrier Lock becomes ‘false’, it can return to the data transmission state. At this time, procedures S109 to S112 can be performed, and the transmission/reception switch fails and returns to the original state. The specific procedures are as follows.

It can be considered that a Receive Duration timeout occurs in the Wait for Carrier state (procedure in S106) or the Carrier signal is cut off in the Awaiting First Frame state seeking frame synchronization (procedure in S107). (S109) At this time, it switches from reception to transmission mode. (S110) Next, a carrier signal is transmitted so that the other party can synchronize the frequency during the Carrier Only Duration. (S111) Next, the Acquisition Sequence for frame synchronization is transmitted during the Acquisition Idle Duration. (S112) After that, data can be transmitted again.

At this time, referring to FIG. 2, the specific procedure for switching from Lander operating in reception mode to transmission mode is as follows. Receive data in data reception state. (S201) At this time, an SPDU frame containing token information indicating transmission/reception switching is received based on FIG. 1. After that, Tail Idle is received. Next, Receive Duration Timeout occurs. (S202) At this time, data continues to be received as long as the Receive Duration Timeout does not occur, and if the Receive Duration Timeout occurs, the next step “S203” is performed. In step S203, it is checked whether the carrier signal is disconnected (Carrier Lock=false). (S203) Next, when the carrier signal is cut off, it switches from reception to transmission mode. (S204) Next, a carrier signal is transmitted so that the other party can synchronize the frequency during the Carrier Only Duration. (S205) Next, an Acquisition Sequence for frame synchronization is transmitted during the Acquisition Idle Duration. (S206) Next, the data transmission state is established and data can be transmitted. (S207)

Meanwhile, when state S202 is reached, it is possible to immediately determine whether the carrier is locked. At this time, when Carrier Lock=false in step 203, switching from reception to transmission mode is possible.

At this time, the process of sending and receiving data and ACK frames through a transmission/reception switching procedure using Go-Back-N ARQ in half duplex mode may be as shown in FIG. 3.

Rover, which transmits data using Go-Back-N ARQ, can transmit frames equal to the size of the transmission window, starting from procedure S301 in FIG. 3. (S301) Then, after switching to the reception mode in the same manner as in FIGS. 1 and 2, data including an ACK frame can be received (steps S302 to S307). (S308) After that, it returns to the transmission state again based on Figs. 1 and 2 (S309 to S313). On the other hand, Lander can receive N frames starting from step S308, which is the data reception state. (S308) Afterwards, the system switches to the transmission mode as described above (S309 to S313), transmits data including an ACK frame, returns to the reception state in step S301, and repeats the same operation.

However, steps S314 to S317 may be a process in which the transmitting side fails to switch to the receiving mode and returns to the original transmitting state. As shown in Figure 3, in order to return to the original state after exchanging ARQ feedback, transmission and reception conversion must occur twice in each communication device.

However, if Lander has no data to transmit other than ARQ feedback and all frames are received without transmission errors, performing two transmission/reception switches to send an ACK frame is a huge waste of time and power. In this situation, the present invention transmits a carrier signal longer than the basic Carrier Only Duration while the receiving side attempts to switch to the transmission mode and returns to the reception mode without transmitting the Acquisition Sequence, so there is no transmission error for all received frames. We propose a method for responding to ARQ. In other words, if the carrier signal is cut off after receiving a carrier signal that is longer than the default, the rover recognizes that it has received ARQ feedback showing no transmission error and transmits the frame number by one in the next transmission. When the Rover receives ARQ feedback indicating that there is no transmission error, procedures S314 to S317 of FIG. 3 are performed by the protocol and automatically returns to the transmission mode. Therefore, the proposed method allows ARQ response with only one transmission/reception attempt. However, when an actual transmission error occurs, the number of the frame in which the error occurred must be transmitted, so it can only be used when the receiver receives all frames without transmission errors.

Figure 4 shows the process of processing an ARQ response by the method proposed by Rover.

The specific procedure by which Rover processes ARQ responses in the proposed method is as follows. At this time, steps S401 to S406 are conversion procedures to the normal reception mode and may be the same as those in FIGS. 1 to 3 described above. Next, you can wait until the Carrier signal is cut off in step S407 and Carrier Lock=false. (S407)

Afterwards, when Carrier Lock=false, the Carrier Lock Duration, which is the time the Carrier Lock lasts, is compared with the Carrier Only Duration, and if the Carrier Lock Duration is longer than the Carrier Only Duration, it can be regarded as an ARQ response with no transmission error. (S408) That is, step S408 may be a step of checking whether ARQ feedback is present. Next, when you return to step S406, Carrier Lock=false is in the state, so you can proceed to step S409. At this time, a Receive Duration timeout occurs in step S409. (S409) Next, it switches from reception to transmission mode. (S410) Next, a carrier signal is transmitted so that the other party can achieve frequency synchronization during the Carrier Only Duration. . (S411) Next, the Acquisition Sequence for frame synchronization is transmitted during the Acquisition Idle Duration. (S412) Through this, when only the ACK frame is received, the current state can be maintained by returning to the transmission mode.

However, if a transmission error occurs in the received frame or there is data to transmit, the Lander can normally transmit the basic length Carrier signal and Acquisition Sequence. In other words, the Carrier Lock Duration may be shorter than the Carrier Only Duration, and in this case, data can be received through step S413. (S414)

Figure 5 shows the process of transmitting ARQ feedback using the method proposed by Lander. Referring to Figure 5, the specific procedure for Lander to transmit an ARQ response is as follows. Steps S501 to S504 are the same as the procedure for switching to the normal transmission mode, and may be similar to FIGS. 1 to 4 described above.

Next, you can check whether there are transmission errors in the received data or whether there is data to be transmitted. (S505) At this time, if there is no transmission error in the received data or there is no data to transmit, the Carrier Only Duration is increased. (S506) At this time, ARQ feedback without transmission error is transmitted by sending a carrier signal longer than the basic Carrier Only Duration. (S507) That is, in FIG. 4 described above, if there is no transmission error, the Carrier Lock Duration may be longer than the Carrier Only Duration, and through this, it can be recognized that there is no transmission error. Next, the transmission mode is switched to the reception mode (S508). Since the transmission side has switched to the reception mode, steps S509 to S511 may be the same as the procedure for finding synchronization when the transmission side switches to the reception mode. Additionally, steps S512 and S513 may be the same as the normal transmission mode switching procedure and may be similar to FIGS. 1 to 4 described above.

In other words, the present invention has the effect of reducing time wastage due to the conversion by confirming the feedback through only the initial operation of the (transmission->reception) conversion in the (transmission->reception) -> feedback transmission -> (reception->transmission) process. Additionally, because the loss caused by the half duplex conversion process is reduced, the ARQ window size can be reduced to reduce unnecessary retransmissions in Go-Back-N ARQ. In the proposed method, it may be a problem if there is an error in judging feedback information, but if upper layer retransmission is performed or the feedback corresponding to the present invention is used n times continuously as defined by the administrator, the actual feedback message is transmitted through transmission and reception switching once each. You can solve the problem by doing this. That is, if the receiver uses ARQ feedback through the Carrier Only Duration interval length n times in succession, the feedback can be transmitted through normal half-duplex transmission and reception switching, thereby solving the above-mentioned problem.

Figure 6 is a block diagram of a device to which the present invention can be applied.

The device 100 to which the present invention can be applied may include a transmitter 110 that transmits a wireless signal, a receiver 120 that receives the wireless signal, and a process 130 that controls the transmitter 110 and the receiver 120. You can. At this time, the device 100 to which the present invention can be applied can communicate with an external device through the transmitter 110 and the receiver 120. At this time, the external device may be another device or a device capable of performing communication, and is not limited to the above-described embodiment.

In addition, the device 100 of the present invention described above can be implemented as various types of devices and is not limited to the above-described embodiment.

Although the above-described exemplary methods of the present disclosure are expressed as a series of operations for clarity of explanation, this is not intended to limit the order in which the steps are performed, and each step may be performed simultaneously or in a different order if necessary. there is. In order to implement the method according to the present disclosure, other steps may be included in addition to the exemplified steps, some steps may be excluded and the remaining steps may be included, or some steps may be excluded and additional other steps may be included.

The various embodiments of the present disclosure do not list all possible combinations but are intended to explain representative aspects of the present disclosure, and matters described in the various embodiments may be applied independently or in combination of two or more.

Additionally, various embodiments of the present disclosure may be implemented by hardware, firmware, software, or a combination thereof. For hardware implementation, one or more ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), general purpose It can be implemented by a processor (general processor), controller, microcontroller, microprocessor, etc.

The scope of the present disclosure is software or machine-executable instructions (e.g., operating system, application, firmware, program, etc.) that cause operations according to the methods of various embodiments to be executed on a device or computer, and such software or It includes non-transitory computer-readable medium in which instructions, etc. are stored and can be executed on a device or computer.

110: transmitting unit
120: receiving unit
130: processor

Claims (10)

In the method of transmitting data using Automatic Repeat Request (ARQ) in half duplex mode of short-range wireless communication for space exploration,
a half-duplex transition preparation step including a transition from a receive mode to a transmit mode;
After switching to the transmission mode, determining whether to increase the length of the Carrier Only Duration section;
Here, if there is no transmission error in the data received in the half duplex switching preparation step and there is no data to transmit, the length of the carrier-only duration section is increased to a length for ARQ feedback that is longer than the basic carrier-only duration,
Transmitting a carrier with the increased carrier-only duration interval length; and
Comprising: a data reception preparation step including switching from transmission mode to reception mode after transmitting the carrier;
Transmitting a carrier of the increased carrier-only duration interval length indicates transmission of ARQ (Automatic Repeat Request) feedback without transmission errors. According to paragraph 1,
The step of determining whether to increase the length of the carrier-only duration section is:
If there is a transmission error in the data received in the half duplex switching preparation step or there is data to be transmitted, a decision is made not to increase the carrier only duration section length,
Transmitting a carrier with a basic carrier only duration section length; and
A data transmission method further comprising: transmitting a sequence for frame synchronization.
According to paragraph 1,
The half-duplex conversion preparation step is,
After receiving data, check the carrier signal when a token is received or a Receive Duration Timeout occurs.
A data transmission method that switches from reception mode to transmission mode when the carrier signal is lost.
According to paragraph 1,
The data reception preparation step is,
A data transmission method comprising waiting for a carrier signal after switching to a reception mode, and receiving data when a normal frame is received after receiving the carrier signal.
According to paragraph 1,
A data transmission method, wherein the carrier is for frequency synchronization.
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