Frame transmission method and wireless communication apparatus performing the same

A frame transmission method and a wireless communication apparatus performing the same. A frame transmission method performed by a first wireless communication apparatus includes receiving subframe unit length information of a second wireless communication apparatus from the second wireless communication apparatus, determining a subframe unit length of the first wireless communication apparatus based on the received subframe unit length information, generating a plurality of subframes based on the determined subframe unit length, and transmitting a frame in which the generated subframes are aggregated to the second wireless communication apparatus, and wherein, when at least one of the subframes includes a padding, a length of the padding allows a length of the at least one of the subframes including the padding to be a multiple of a natural number of the determined subframe unit length.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the priority benefit of Korean Patent Application No. 10-2015-0169204, filed Nov. 30, 2015, Korean Patent Application No. 10-2015-0180974, filed Dec. 17, 2015, Korean Patent Application No. 10-2016-0123322, filed Sep. 26, 2016, and Korean Patent Application No. 10-2016-0154737, filed Nov. 21, 2016, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference for all purposes.

BACKGROUND

One or more example embodiments relate to a frame transmission method and a wireless communication apparatus performing the same.

2. Description of Related Art

For wireless close proximity communication, there exists high rate wireless personal area network (WPAN) technology that supports a high transmission rate over a short distance. In a WPAN, a piconet may include at least one device and one piconet coordinator (PNC). A device associated with a parent piconet may become a PNC and thereby a child piconet may be formed. In a mesh network including a parent piconet and child piconets, a multi hop network is possible.

SUMMARY

According to an aspect, there is provided a frame transmission method performed by a first wireless communication apparatus, the method including receiving subframe unit length information of a second wireless communication apparatus from the second wireless communication apparatus, determining a subframe unit length of the first wireless communication apparatus based on the received subframe unit length information, generating a plurality of subframes based on the determined subframe unit length, and transmitting a frame in which the generated subframes are aggregated to the second wireless communication apparatus, wherein, when at least one of the subframes includes a padding, a length of the padding allows a length of the at least one of the subframes including the padding to be a multiple of a natural number of the determined subframe unit length.

The determined subframe unit length may be a greatest subframe unit length among subframe unit lengths supported by both the first wireless communication apparatus and the second wireless communication apparatus.

A last subframe among the subframes may not include the padding.

When the determined subframe unit length is N, the length of the padding may be one of 0 through N−1 and N is a natural number.

At least one of the subframes may include a payload and whether the padding is included in the at least one of the subframes is determined based on a length of the payload.

The subframe unit length information of the second wireless communication apparatus may be included in an association request frame transmitted by the second wireless communication apparatus.

The method may further include transmitting a beacon frame including subframe unit length information of the first wireless communication apparatus to the second wireless communication apparatus.

According to another aspect, there is provided a first wireless communication apparatus including a communicator configured to receive subframe unit length information of a second wireless communication apparatus from the second wireless communication apparatus, and a processor configured to determine a subframe unit length of the first wireless communication apparatus based on the received subframe unit length information and generate a plurality of subframes based on the determined subframe unit length, wherein, when at least one of the subframes includes a padding, a length of the padding allows a length of the at least one of the subframes including the padding to be a multiple of a natural number of the determined subframe unit length.

The determined subframe unit length may be a greatest subframe unit length among subframe unit lengths supported by both the first wireless communication apparatus and the second wireless communication apparatus.

DETAILED DESCRIPTION

Hereinafter, examples are described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements, and a known function or configuration will be omitted herein.

FIG. 1is a flowchart illustrating a wireless communication method according to an example embodiment.

Referring toFIG. 1, the wireless communication method performed by a wireless communication apparatus may generate a frame, for example, a data frame and a communication frame, in a close proximity wireless communication system through below described processes and transmit the generated frame to another wireless communication apparatus. For example, the wireless communication apparatus may aggregate data of a media access control (MAC) packet and generate a MAC frame.

In operation110, the wireless communication apparatus generates a frame including a plurality of MAC subframes. For example, the wireless communication apparatus may generate a MAC frame by aggregating a plurality of MAC subframes. Here, the wireless communication apparatus may add a padding, hereinafter also referred to as a PAD, being additional data for adjusting a length (or a size) of a subframe to at least one of subframes when needed. The padding may be provided, for example, in a bit unit or a byte unit, and a value of a bit string of the padding may be variously defined.

For example, a length of a padding to be included in a subframe may be determined based on a length of a payload of the subframe. The wireless communication apparatus may adjust the length of the subframe based on a unit for data processing and the length of the padding may be determined based on the corresponding unit for data processing. The wireless communication apparatus may generate a frame by connecting a plurality of subframes. A last subframe among the connected subframes may not include the padding according to an example embodiment. The wireless communication apparatus may store the generated frame in a frame memory.

In operation120, the wireless communication apparatus may transmit the generated frame to another wireless communication apparatus. A subheader is included in the frame, and another wireless communication apparatus may obtain information for dividing the frame from information included in the subheader. Another wireless communication apparatus that receives the frame may separate the plurality of subframes from the frame based on the information included in the subheader.

FIG. 2illustrates a frame transmission method performed between wireless communication apparatuses according to an example embodiment.

Referring toFIG. 2, at least one of a first wireless communication apparatus210and a second wireless communication apparatus220may generate a frame and transmit the frame to a counterpart apparatus.

The second wireless communication apparatus220transmits subframe unit length information of the second wireless communication apparatus220to the first wireless communication apparatus210in operation230. The subframe unit length information of the second wireless communication apparatus220refers to information on a length of a subframe, and the information is a reference used for generating each subframe. The subframe unit length information of the second wireless communication apparatus220may be included in an association request frame transmitted by the second wireless communication apparatus220.

The first wireless communication apparatus210receives the subframe unit length information of the second wireless communication apparatus220from the second wireless communication apparatus220, and determines a subframe unit length of the first wireless communication apparatus210based on the received subframe unit length information in operation240. For example, the first wireless communication apparatus210may determine, as the subframe unit length of the first wireless communication apparatus210, a greatest subframe unit length among subframe unit lengths supported by both the first wireless communication apparatus210and the second wireless communication apparatus220.

The first wireless communication apparatus210generates the subframes based on the determined subframe unit length in operation250. The first wireless communication apparatus210may adjust a length of a subframe by adding a padding to the subframe when a length of a subframe to be generated is different from the determined subframe unit length. A length of a padding included in a subframe allows a length of the subframe including the padding to be a multiple of a natural number of the determined subframe unit length. The first wireless communication apparatus210may exclude the padding from the last subframe when the subframes are generated.

When the determined subframe unit length is N (natural number), the length of the padding may be one of 0 through N−1. The length of the padding being 0 indicates that the padding is not included in the subframe. The subframe may include a payload and whether the padding is included in the subframe may be determined based on a length of the payload. For example, when it is assumed that the determined subframe unit length is 4 bytes, a length of a header of the subframe is 4 bytes, and a length of a frame check sequence (FCS) is 4 bytes, (1) the length of the padding may be 0 bytes when the length of the payload of the corresponding subframe is 8 bytes (that is, the padding is not included), (2) the length of the padding may be 3 bytes when the length of the payload of the corresponding subframe is 9 bytes, (3) the length of the padding may be 2 bytes when the length of the payload of the corresponding subframe is 10 bytes, and (4) the length of the padding may be 1 byte when the length of the payload of the corresponding subframe is 11 bytes. According to another example, the length of the padding may be determined in bits.

The first wireless communication apparatus210generates a frame in which the subframes are aggregated and transmits the generated frame to the second wireless communication apparatus220in operation260.

The first wireless communication apparatus210may also transmit subframe unit length information of the first wireless communication apparatus to the second wireless communication apparatus220. Here, the first wireless communication apparatus210may add the subframe unit length information of the first wireless communication apparatus210to a beacon frame, and transmit the beacon frame to the second wireless communication apparatus220. The second wireless communication apparatus220determines the subframe unit length based on the subframe unit length information of the first wireless communication apparatus210in operation270. For example, the second wireless communication apparatus220may also determine, as the subframe unit length of the second wireless communication apparatus220, the greatest subframe unit length among the subframe unit lengths supported by both the first wireless communication apparatus210and the second wireless communication apparatus220. The second wireless communication apparatus220generates the subframes based on the determined subframe unit length in operation280, and transmits the frame in which the subframes are aggregated to the first wireless communication apparatus210.

FIG. 3is a block diagram illustrating a structure of a close proximity wireless communication system according to an example embodiment.

In an example, a wireless communication apparatus may store, in a media access control service data unit (MSDU) memory320, data generated on an application layer310in a form of an MSDU. A MAC layer330may generate a MAC frame by reading the MSDU from the MSDU memory and store the generated MAC frame in a frame memory340.

In an example, a physical (PHY) layer350of the wireless communication apparatus may generate a PHY frame by reading the MAC frame from the frame memory340, and the generated PHY frame may be wirelessly transmitted through a radio frequency (RF)360.

In an example, a process of receiving the PHY frame may be performed in a reverse order of a transmitting process described with reference toFIG. 3.

Referring toFIGS. 4 through 6, a MAC frame is described as an example of a frame. However, a scope of an example is not limited to a MAC frame, and a technical description of the present disclosure may be also applicable even when various frames are generated.

FIG. 4is a diagram illustrating a structure of a media access control (MAC) frame body of an aggregated frame according to an example embodiment. In an example, a wireless communication apparatus may use the aggregated frame to enhance an efficiency of data transmission. A structure of the aggregated frame may differ based on a physical (PHY) layer to be used.

Referring toFIG. 4, a frame check sequence (FCS) and a padding are added to a single MAC payload, and a subframe header is added based on an aggregation method to form a single MAC subframe. The padding may be additional data used for adjusting a length of the MAC subframe. The padding may be used as dummy data for adjusting the length of the MAC subframe.

In an example, a MAC frame body of the aggregated frame may include at least one MAC subframe. Here, a MAC subheader may be an optional header, and another wireless communication apparatus may receive the aggregated frame and include information required for separating the received aggregated frame. The MAC subheader may be transmitted and received on the PHY layer through a process that is the same as a process used to transmit a PHY header and a MAC header.

In an example, the MAC subframe included in the structure of the aggregated frame may include MSDU data being a payload, a 4-byte subframe header, and a 4-byte FCS. Because a payload of the subframe has a variable length, a 0 through 3-byte length of padding may be added based on the length of the payload. For example, when the length of the payload is 5 bytes, the length of the padding may be 3 bytes. As another example, when the length of the payload is 7 bytes, the length of the padding may be 1 byte. Here, although the padding may be composed of 0-bit and/or 1-bit units, a bit string configuration of the padding is not limited thereto.

FIG. 5Ais a diagram illustrating a data form stored in a media access control service data unit (MSDU) memory according to an example embodiment.

As a transmission rate of a close proximity wireless communication is increased, data may be more frequently processed in 4-byte units in a close proximity wireless communication system. However, a volume of an MSDU memory formed on an application layer may have a byte unit. In this case, as illustrated inFIG. 5A, MSDU data stored in the MSDU memory may have an empty space in an end portion of the MSDU memory, similar to first MSDU data and third MSDU data.

However, the frame memory including an aggregated frame may not require an empty space. When a size of an end portion of the first MSDU data is 3 bytes, a size of an end portion of a first subframe may be also 3 bytes. Thus, 1-byte of data of each portion of a second subframe may be used to fill the empty space of the first subframe. In a receiving process, conversely, a process of using 1 byte of second MSDU data corresponding to a second payload of the second subframe may be required. In the close proximity wireless communication system, a process of using and filling a portion of data may be considerably inconvenient and cause a decrease in performance.

The present disclosure may solve such issue through the proposed aggregated frame structure, such that the close proximity wireless communication system may be easily implemented and performance of the close proximity wireless communication system may be enhanced.

FIG. 5Bis a diagram illustrating a data form stored in a frame memory according to an example embodiment.

In an example, a wireless communication apparatus may store data in a frame memory as illustrated inFIG. 5B. A MAC subframe included in a structure of an aggregated frame may include MSDU data being a payload of a subframe, a 4-byte subframe header, and a 4-byte FCS. Also, a 0 through 3-byte length of padding may be added to a subframe based on a length of the payload. The padding may be additional data for adjusting a length of the subframe.

In an example, a length of the padding may be determined based on a length of the subframe or a length of the payload. For example, the wireless communication apparatus may determine the length of the padding such that the length of the MAC subframe is a multiple of 4 bytes corresponding to a unit length of the subframe. Here, the padding may include any type of data. For example, the padding may be filled with 0-bit and/or 1-bit units.

Referring toFIG. 5B, the padding may be included in each of the first subframe and the third subframe such that the length of the subframe is a multiple of a subframe unit length. When the length of the subframe is a multiple of the subframe unit length, the padding may not be included in the subframe as in the second subframe. For example, the wireless communication apparatus may exclude the padding from a last subframe to be included in the aggregated frame in order to enhance the transmission efficiency.

FIG. 6is a diagram illustrating a structure of a media access control (MAC) subframe according to an example embodiment.

Referring toFIG. 6, when a unit for data processing in a close proximity wireless communication system is increased to be a 8-byte unit or a 16-byte unit other than a 4-byte unit, a wireless communication apparatus may adjust a length of a padding included in a media access control (MAC) subframe to be 0 bytes through 7 bytes (when the length of the MAC subframe is 8 bytes) or 0 bytes through 15 bytes (when the length of the MAC subframe is 17 bytes) such that the length of the MAC subframe is 8 bytes or 16 bytes.

In an example, the length of the padding may be determined based on bytes of the length of the MAC subframe. For example, when the length of the MAC subframe is 8 bytes, the length of the padding may be 0 bytes through 7 bytes in a structure of the MAC subframe. When the length of the MAC subframe is set to be N bytes, the length of the padding may be 0 bytes through N−1 bytes.

Based on a method used for implementing a system, data may be processed in a 4-byte unit or a 8-byte unit. When units of data processed by two systems are different, a system that processes data based on a relatively large unit for data processing may be used such that communication may be possible. Thus, in the present disclosure, wireless communication apparatuses may exchange respective pieces of subframe unit length information corresponding to information on a desired length of a MAC subframe before respective pieces of aggregated data are exchanged, such that the length of the MAC subframe to be exchanged by the wireless communication apparatuses may be determined based on the exchanged pieces of information. The wireless communication apparatus may compare the exchanged pieces of information and determine a subframe unit length of which a value is relatively great as a unit length to be applied to subframes to be generated.

The aforementioned process performed by the wireless communication apparatus may be performed in an association process of close proximity wireless communication. Subframe unit length information may be included in a capability information element included in a beacon frame, and an association request frame or an association response frame.

In an example, a first wireless communication apparatus may receive the subframe unit length information on the desired length of the MAC subframe from a second wireless communication apparatus. When the received subframe unit length information is greater than subframe unit length information of the first wireless communication apparatus, the first wireless communication apparatus may determine the length of the MAC subframe based on the received subframe unit length information. Here, the subframe unit length information may be included in the association request frame transmitted by the second wireless communication apparatus. In another example, the first wireless communication apparatus may transmit first subframe unit length information on the length of the MAC subframe to the second wireless communication apparatus, and receive second subframe unit length information on the length of the MAC subframe from the second wireless communication apparatus. The first subframe unit length information may be included in the beacon frame or the association response frame transmitted by the first wireless communication apparatus, and the second subframe unit length information may be included in the association request frame transmitted by the second wireless communication apparatus. The length of the MAC subframe to be generated by the first wireless communication apparatus may be determined based on subframe unit length information that is greater between the first subframe unit length information and the second subframe unit length information.

FIG. 7is a block diagram illustrating a configuration of a first wireless communication apparatus and a second wireless communication apparatus for close proximity communication according to an example embodiment.

Referring toFIG. 7, a first wireless communication apparatus710and a second wireless communication apparatus720may correspond to the first wireless communication apparatus210and the second wireless communication apparatus220ofFIG. 2, respectively.

The first wireless communication apparatus710includes a communicator714and a processor715. The communicator714transmits a beacon, a frame, a signal, data, information, or subframe unit length information of the first wireless communication apparatus710to the second wireless communication apparatus720, or receives a beacon, a frame, a signal, data, information, or subframe unit length information of the second wireless communication apparatus720from the second wireless communication apparatus720.

The processor715may perform at least one of operations described with reference toFIGS. 1 through 6. For example, the processor715determines a subframe unit length of the first wireless communication apparatus710based on the subframe unit length information of the second wireless communication apparatus720and generates a plurality of subframes based on the determined subframe unit length. The processor715generates a frame by aggregating the generated subframes.

The second wireless communication apparatus720includes a communicator724and a processor725. The communicator724transmits the frame, the signal, the data, the information, or the subframe unit length information of the second wireless communication apparatus720to the first wireless communication apparatus710, or receives the frame, the signal, the data, the information, or the subframe unit length information of the first wireless communication apparatus710from the first wireless communication apparatus710.

The processor725may perform at least one of operations described with reference toFIGS. 1 through 6. For example, the processor725determines the subframe unit length of the second wireless communication apparatus720based on the subframe unit length information of the first wireless communication apparatus710, and generates the plurality of subframes based on the determined subframe unit length. The processor generates a frame by aggregating the generated subframes.

The components described in the exemplary embodiments of the present invention may be achieved by hardware components including at least one DSP (Digital Signal Processor), a processor, a controller, an ASIC (Application Specific Integrated Circuit), a programmable logic element such as an FPGA (Field Programmable Gate Array), other electronic devices, and combinations thereof. At least some of the functions or the processes described in the exemplary embodiments of the present invention may be achieved by software, and the software may be recorded on a recording medium. The components, the functions, and the processes described in the exemplary embodiments of the present invention may be achieved by a combination of hardware and software.