KR20090048301A - Method and apparatus for generating data frame - Google Patents

Abstract

The present invention relates to a method of generating a data frame, wherein an embodiment of the present invention generates subframes from at least one Mac Service Data Unit (MSDU) and errors during transmission of subframes for each of those subframes. After generating a retransmission policy field for recording a policy related to the retransmission request in case of occurrence of the error, and generates a data frame using the retransmission policy field generated for each of the subframes and the subframes.

Description

Method and apparatus for generating data frame

The present invention relates to a method and apparatus for generating a data frame.

WPAN is a network that provides wireless connectivity in a relatively short personal operating space, such as a home or office. In WPAN, devices communicate in a TDMA manner in a piconet that has a range of about 10m and forms an ad hoc network.

The IEEE 802.15 Working Group (WG) was created to provide a communication standard in the Personal Operating Space, and among the four TGs (Task Group) belonging to the IEEE 802.15 WG, IEEE 802.15.3 provides high-speed data. The standardization of HR (High Rate) -WPAN for transmission is completed.

1 is a diagram illustrating a structure of a general data frame used in a WPAN.

The preamble 110 is a field in which patterns for packet detection, symbol synchronization, frequency synchronization, and the like are recorded.

The PHY header 120 is a field in which information on the length of the frame body, the data rate of the frame body, and the like is recorded. The PHY header 120 is a header of the physical layer, and the MAC header 130 is a header used in the MAC layer.

The MAC Service Data Unit (MSDU) 140 is data that the MAC layer receives from the upper layer, and is a part of the payload of the MAC Protocol Data Unit (MPDU) delivered to the PHY layer through the service of the MAC layer.

The frame check sequence (FCS) 150 is a field in which a cyclic redundancy check (CRC) code is recorded so that a reception side can detect such an error when an error due to transmission occurs in a data frame.

The object of the invention relates to a method and an apparatus for generating a data frame.

A data frame generation method according to an embodiment of the present invention for achieving the above object comprises the steps of generating subframes from at least one Mac service data unit (MSDU); Generating a retransmission policy field for recording a policy associated with a retransmission request in case an error occurs during transmission of the subframes for each of the subframes; And generating a data frame using the retransmission policy field generated for each of the subframes and the subframes.

Preferably, the subframes include at least one of first type bits and second type bits extracted from the at least one MSDU, and the policy related to the retransmission request is when an error occurs during transmission of the subframes. A policy for not allowing a retransmission request for a subframe in which an error occurs; A policy for allowing a retransmission request for the entire subframe in which the error occurs; A policy for allowing only a retransmission request for the first type bits of the subframe in which the error occurs; And a policy for allowing only a retransmission request for the second type bits of the subframe in which the error occurs. .

Preferably, the subframes further include at least one of a frame check sequence (FCS) field for detecting an error of the first type bits and an FCS field for detecting an error of the second type bits.

Preferably, the method for generating a data frame according to an embodiment of the present invention determines whether the subframes are composed of bits of the first type bits or the second type bits for each of the subframes. Generating a subframe information field, wherein the generating of the data frame comprises data using the subframe information field and the retransmission policy field generated for each of the subframes and the subframes. Create a frame.

Preferably, the method for generating a data frame according to an embodiment of the present invention further includes generating a subheader including the retransmission policy field and the subframe information field for each of the subframes. The generating of the data frame may be performed using the subframes and the subheaders generated for each of the subframes.

Preferably, the sub header includes an MCS field indicating a modulation and coding scheme (MCS) applied to each of the subframes, and an FCS field for detecting an error of the subframes in each of the subframes. An FCS information field indicating whether the subframe is present, an MSDU identification field including information for identifying an MSDU used for generating each of the subframes, a fragmentation information field indicating whether the subframes are fragmented, and the It further includes at least one of the length field indicating the length of each of the sub-frames.

Preferably, the generating of the data frame generates the data frame using the subframes, the subheader, the PHY header, and the MAC header generated for each of the subframes.

Preferably, the sub header, the PHY header and the MAC header generated for each of the subframes are generated by applying an MCS that yields a lower data rate than the MCS applied to the subframes.

Preferably, the policy associated with the retransmission request is recorded in binary form in the retransmission policy field.

In addition, a data frame generating apparatus according to an embodiment of the present invention for achieving the above object comprises a sub-frame generating unit for generating sub-frames from at least one Mac service data unit (MSDU); A field generation unit for generating a retransmission policy field for recording a policy related to a retransmission request in case an error occurs during transmission of the subframes for each of the subframes; And a data frame generator for generating a data frame using the retransmission policy field generated for each of the subframes and the subframes.

Preferably, the apparatus for generating a data frame according to an embodiment of the present invention further includes a header generator for generating a subheader including the retransmission policy field and the subframe information field for each of the subframes. The frame generator generates a data frame using the subframes and the subheaders generated for each of the subframes.

In addition, an embodiment of the present invention includes generating subframes from at least one Mac service data unit (MSDU) to achieve the above object; Generating a retransmission policy field for recording a policy associated with a retransmission request in case an error occurs during transmission of the subframes for each of the subframes; And generating a data frame by using the retransmission policy field generated for each of the subframes and the subframes. To provide.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2 is a flowchart illustrating an embodiment of a data frame generation method according to the present invention.

In step 210, subframes are generated from at least one Mac service data unit (MSDU).

Here, the MSDU may be composed of most significant bits (MSB) and least significant bits (LSB).

If the MSDU is data compressed through a compression algorithm such as MPEG or JPEG, all bits will have the same importance. If uncompressed data such as RGB data, the information contained in each bit will have different importance. For example, in the case of RGB data, the upper four bits of one byte generally have more important information than the lower four bits. As such, the relatively significant bits in each byte of the MSDU are referred to as More Significant Bits (MSB) and the less significant bits as LSB (Less Significant Bits). How many bits from one byte become the MSB may vary depending on the type of data and the implementation. However, all bits other than the MSB in one byte become LSBs.

In this case, the subframes may be configured to include at least one of the MSB and LSB extracted from the MSDU. That is, three types of subframes may be generated, such as a subframe composed of the MSB and the LSB, a subframe composed only of the MSB, and a subframe composed only of the LSB.

According to an embodiment, an FCS field for detecting an error of an MSB and an FCS field for detecting an error of an LSB may be added to the subframes.

For example, the FCS field for the MSB or the FCS field for the LSB may be added to each of the subframes, or both the FCS field for the MSB and the FCS field for the LSB may be added.

In operation 220, a retransmission policy field is generated for recording a policy related to the retransmission request in case an error occurs during transmission of the subframes for each subframe.

An error may occur when the subframes are transmitted to another device, and the device that receives the subframes may request that the device transmitting the subframes retransmit the subframe in which the error occurs.

Such a request is called a retransmission request, and the policy associated with the retransmission request is whether to allow such a retransmission request, allow only retransmission requests for the MSB or LSB, or allow retransmission requests for both the MSB and LSB. Say the relevant policy.

For example, the retransmission policy field does not allow a retransmission request for a subframe in which the error occurs when 00 is recorded in the retransmission policy field, and an error occurs when 01 is recorded in the retransmission policy field. It may be configured to allow a retransmission request for the entire subframe.

In addition, the retransmission policy field allows only a retransmission request for the MSB among the subframes in which an error occurs when 10 is recorded in the retransmission policy field, and only a retransmission request for the LSB in the subframe in which the error occurs when 11 is recorded in the retransmission policy field. Can be configured.

In operation 230, a data frame is generated using the subframes and the retransmission policy field generated for each of the subframes.

As in the present embodiment, when the device receives the data frame including the retransmission policy field, when an error occurs during the reception of the subframe, the device may request a retransmission request for the subframe in which the error occurs according to the policy set in the retransmission policy field. do.

For example, when a transmission error occurs in a subframe in which 10 is recorded in the retransmission policy field, even if an error occurs in both the MSB and LSB of the subframe, the device that receives the subframe transmits the subframe. It is requested to retransmit only the MSB of the subframe. In addition, when a transmission error occurs only in the LSB of the subframe, the device that receives the subframe will not request retransmission to the device that transmitted the subframe.

As described above, according to one embodiment of the present invention, since a policy for retransmission request can be determined and transmitted for each subframe included in the data frame, when a transmission error occurs in a subframe that does not require retransmission. This has the advantage of preventing unnecessary retransmission requests.

3 is a diagram illustrating an embodiment of a data frame structure according to the present invention.

Referring to FIG. 3, a data frame according to an embodiment of the present invention includes a PHY header 310, a MAC header 320, an HCS field 330 for headers, subheaders 340, and subheaders. HCS field 350, subframes 360.

The PHY header 310 is a field in which information on the length of the frame body, the data rate of the frame body, and the like is recorded. The PHY header 310 is a header of the physical layer, and the MAC header 320 is a header used in the MAC layer.

The HCS field 330 for the headers is a field in which a header check sequence (HCS), which is a CRC code for detecting an error of the PHY header 310 and the MAC header 320, is recorded.

The subheaders 340 include information about each of the subframes, and include an MCS field 341, an FCS information field 342, a retransmission policy field 343, an MSDU number field 344, and a fragmentation information field 345. ), A length field 346, a subframe information field 347, and a reservation field 348.

The MCS field 341 represents a Modulation and Coding Scheme (MCS) applied to each of the subframes.

The FCS information field 342 indicates whether each of the subframes includes an FCS field for detecting an error of the subframes. For example, when 1 is recorded in the FCS information field 342, the FCS field for the MSB and the FCS field for the LSB are added to the subframe, and when 0 is recorded, there may be no FCS field added.

The device receiving the data frame determines whether a transmission error has occurred for the received subframe based on the FCS field added to the subframe.

The MSDU number field 344 is a field for recording the number of the MSDU used to generate each of the subframes 360 to identify which MSDU used to generate each of the subframes 360. However, in some embodiments, the MSDU identification field may be included instead of the MSDU number field 344, and an identifier for identifying the MSDU may be recorded in the MSDU identification field instead of the MSDU number.

The subframe information field 345 indicates how each of the subframes is configured. For example, the subframe information field 345 may indicate that the subframe consists of the MSB and the LSB, or only the MSB or the LSB.

The fragmentation information field 345 indicates whether subframes are fragmented.

The length field 346 indicates the length of each of the subframes.

Reserved field 348 is a field that is left unused for future use.

In some implementations, the PHY header 310, the MAC header 320, the HCS field 330 for the headers, the subheader 340, and the HCS field 350 for the subheader are subframes 360. MCS, which yields a lower data rate than that applied to MCS, may be applied.

Accordingly, the probability that an error occurs in the PHY header 310, the MAC header 320, the HCS field 330 for the headers, the subheader 340, and the HCS field 350 for the subheader is determined by subframes 360. Will be lower than).

Meanwhile, the device receiving the data frame generated through the above process may request a retransmission for the subframe in which an error occurs by transmitting an acknowledgment frame to the device that transmitted the data frame.

4 is a diagram illustrating an embodiment of an acknowledgment frame according to the present invention.

Referring to FIG. 4, an acknowledgment frame according to an embodiment of the present invention includes a MAC header 410, a subframe ACked field 420, a subframe ID block field 430, and an FCS field 430.

MAC header 410 is a header used in the MAC layer.

The subframe ACked field 420 indicates the number of subframes that can indicate whether to confirm receipt through the acknowledgment frame of FIG. 4.

The subframe ID block field 420 is a field including information related to the received subframe, and includes an MSDU number field 431, a subframe ID field 432, an MSB retransmission request field 433, and an LSB retransmission request field ( 434 and a reservation field 435.

The MSDU number field 431 is a field for recording the number of the MSDU used to generate the received subframe.

The subframe ID field 432 is a field containing information for identifying the received subframe.

MSB retransmission request field 433 is a field indicating whether to request retransmission for the MSB of the received subframe.

LSB Retransmission Request Field 434 This field indicates whether a retransmission request for the LSB of the received subframe is requested.

At this time, in the MSB retransmission request field 433 and the LSB retransmission request field 434, information on whether to request a retransmission is recorded based on a policy related to the retransmission request included in the received subframe.

For example, if the policy related to the retransmission request is a policy that allows only the retransmission request for the MSB among the subframes in which an error occurs, 1 is recorded in the MSB retransmission request field 433 for the MSB retransmission request, and the LSB retransmission request field ( 0 may be recorded in 433).

Reserved field 435 is a field that is left unused for future use.

Other fields in the acknowledgment frame structure shown in FIG. 4 are described in the IEEE 802.15.3C standard document, and thus description of these fields is omitted.

5 is a diagram illustrating an embodiment of a data frame generation apparatus according to the present invention.

Referring to FIG. 5, an apparatus for generating a data frame according to an embodiment of the present invention includes a subframe generator 510, a field generator 520, a header generator 530, and a data frame generator 540. do.

The subframe generation unit 510 generates a subframe that generates subframes from at least one Mac service data unit (MSDU).

The field generator 520 generates a retransmission policy field for recording a policy related to the retransmission request in case an error occurs during transmission of the subframes for each subframe. In addition, the field generator 520 may generate a subframe information field indicating what type of bits the subframes are configured with respect to each of the subframes.

The header generator 530 generates a subheader, a PHY header, and a MAC header including a retransmission policy field and a subframe information field.

The data frame generator 540 generates a data frame using the subframes, the subheader, the PHY header, and the MAC header generated for each of the subframes.

Meanwhile, the above-described embodiments of the present invention can be written as a program that can be executed in a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium.

The computer-readable recording medium may be a magnetic storage medium (for example, a ROM, a floppy disk, a hard disk, etc.), an optical reading medium (for example, a CD-ROM, a DVD, etc.) and a carrier wave (for example, the Internet). Storage medium).

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1 is a diagram illustrating a structure of a general data frame used in a WPAN.

2 is a flowchart illustrating an embodiment of a data frame generation method according to the present invention.

3 is a diagram illustrating an embodiment of a data frame structure according to the present invention.

4 is a diagram illustrating an embodiment of an acknowledgment frame according to the present invention.

5 is a diagram illustrating an embodiment of a data frame generation apparatus according to the present invention.

Claims (19)

In the data frame generation method, Generating subframes from at least one Mac Service Data Unit (MSDU); Generating a retransmission policy field for recording a policy associated with a retransmission request in case an error occurs during transmission of the subframes for each of the subframes; And Generating a data frame using the subframes and the retransmission policy field generated for each of the subframes. The method of claim 1, The subframes include at least one of first type bits and second type bits extracted from the at least one MSDU, The policy associated with the resend request is A policy for not allowing a retransmission request for an errored subframe when an error occurs during transmission of the subframes; A policy for allowing a retransmission request for the entire subframe in which the error occurs; A policy for allowing only a retransmission request for the first type bits of the subframe in which the error occurs; And  And a policy of allowing only a retransmission request for the second type bits of the subframe in which the error occurs. The method of claim 2, The subframes And at least one of a frame check sequence (FCS) field for detecting errors of the first type bits and an FCS field for detecting errors of the second type bits. The method of claim 2, Generating, for each of the subframes, a subframe information field indicating which type of the first type bits or the second type bits is comprised of the subframes; The generating of the data frame may include generating the data frame using the subframes, the subframe information field generated for each of the subframes, and the retransmission policy field. The method of claim 4, wherein Generating a sub header including the retransmission policy field and the sub frame information field for each of the sub frames; The generating of the data frame may include generating a data frame using the subframes and the subheaders generated for each of the subframes. The method of claim 5, The sub header is MCS field indicating a modulation and coding scheme (MCS) applied to each of the subframes, and FCS information indicating whether an FCS field for detecting an error of the subframes is included in each of the subframes. Field, an MSDU identification field including information for identifying the MSDU used to generate each of the subframes, a fragmentation information field indicating whether the subframes are fragmented, and a length of each of the subframes. And at least one of the length fields indicated. The method of claim 5, Generating the data frame And generating a data frame using the subframes, a subheader, a PHY header, and a MAC header generated for each of the subframes. The method of claim 7, wherein The sub-header, the PHY header and the MAC header generated for each of the sub-frames are generated by applying an MCS whose data rate is lower than that of the MCS applied to the sub-frames. . The method of claim 1, The policy associated with the resend request is And a binary form is recorded in the retransmission policy field. In the data frame generating apparatus, A subframe generation unit generating subframes from at least one Mac service data unit (MSDU); A field generation unit for generating a retransmission policy field for recording a policy related to a retransmission request in case an error occurs during transmission of the subframes for each of the subframes; And And a data frame generator for generating a data frame using the retransmission policy field generated for each of the subframes and the subframes. The method of claim 10, The subframes include at least one of first type bits and second type bits extracted from the at least one MSDU, The policy associated with the resend request is A policy for not allowing a retransmission request for an errored subframe when an error occurs during transmission of the subframes; A policy for allowing a retransmission request for the entire subframe in which the error occurs; A policy for allowing only a retransmission request for the first type bits of the subframe in which the error occurs; And And one of a policy for allowing only a retransmission request for the second type bits of the subframe in which the error occurs. The method of claim 11, The subframes And at least one of a frame check sequence (FCS) field for detecting errors of the first type bits and an FCS field for detecting errors of the second type bits. The method of claim 11, The field generator generates a subframe information field indicating for each type of the subframes, the type of bits of the first type bits or the second type bits. And the data frame generator generates a data frame using the subframe information field and the retransmission policy field generated for each of the subframes and the subframes. The method of claim 13, A header generator configured to generate a subheader including the retransmission policy field and the subframe information field for each of the subframes; And the data frame generator generates a data frame using the subframes and the subheaders generated for each of the subframes. The method of claim 14, The sub header is MCS field indicating a modulation and coding scheme (MCS) applied to each of the subframes, and FCS information indicating whether an FCS field for detecting an error of the subframes is included in each of the subframes. Field, an MSDU identification field including information for identifying the MSDU used to generate each of the subframes, a fragmentation information field indicating whether the subframes are fragmented, and a length of each of the subframes. And at least one of the length fields indicated. The method of claim 14, The data frame generation unit And generating a data frame using the subframes, a subheader, a PHY header, and a MAC header generated for each of the subframes. The method of claim 16, The sub-header, the PHY header and the MAC header generated for each of the sub-frames are generated by applying an MCS whose data rate is lower than that of the MCS applied to the sub-frames. . The method of claim 10, The policy associated with the resend request is And a binary form is recorded in the retransmission policy field. A computer-readable recording medium having recorded thereon a program for executing the method of any one of claims 1 to 9.

Images