HK1102879B - Method and apparatus for transmitting / receiving data in wireless network - Google Patents

Description

Method and apparatus for transmitting/receiving data in wireless network

Technical Field

Methods and apparatuses consistent with the present invention relate to a method and apparatus for transmitting and receiving legacy format data (legacy format data) in a high throughput wireless network.

Background

Due to the widespread public use of the internet and the rapid increase in the amount of multimedia data available, the demand for ultra-high speed communication networks is increasing. Due to the rise of Local Area Networks (LANs) at the end of the 80's in the 20 th century, data transmission rates over the internet have increased dramatically from 1Mbps to 100 Mbps. Thus, high speed ethernet transport has become popular and widely used. Currently, intensive research into gigabit-speed ethernet is being conducted. The increasing interest in wireless network connectivity and communications has led to research into developing Wireless Lans (WLANs) and has greatly increased the availability of WLANs to users. Although the use of WLANs may reduce performance due to lower transmission rates and poor stability compared to wired LANs, WLANs have various advantages, including wireless networking capability, greater mobility, and the like. Thus, the WLAN market has grown gradually.

The initial Institute of Electrical and Electronics Engineers (IEEE)802.11 standard, which specifies a transmission rate of 1 to 2Mbps due to the need for higher transmission rates and development of wireless transmission technology, has been developed into advanced standards including IEEE802.11a, IEEE802.11b, and IEEE802.11 g. The IEEE802.11g standard utilizes a transmission rate of 6 to 54Mbps in the national information architecture (NII) band of 5GHz, using Orthogonal Frequency Division Multiplexing (OFDM) as its transmission technology. With the increasing public interest in OFDM transmission and the use of the 5GHz band, much greater attention has been given to the IEEE802.11g standard and OFDM transmission technology than to other wireless standards.

Recently, a wireless internet service using a WLAN, so-called "Nespot", has been initiated and provided by Korean Telecommunication (KT) corporation in korea. The Nespot service allows access to the internet using a WLAN according to the ieee802.11b standard, commonly known as Wi-Fi (wireless fidelity). Communication standards for wireless data communication systems that have been completed and released or are being discussed include: wideband Code Division Multiple Access (WCDMA), ieee802.11x, bluetooth, ieee802.15.3, and the like are known as third generation (3G) communication standards. The most familiar, cheapest wireless data communication standard is ieee802.11b, which is one of the ieee802.11x series. The ieee802.11b WLAN standard provides data transmission at the highest data transmission rate of 11Mbps and utilizes the industrial, scientific, and medical (ISM) band of 2.4GHz, which can be used without permission under a predetermined electric field. With the recent widespread use of the ieee802.11a WLAN standard that transmits the highest data transmission rate of 54Mbps in the 5GHz band by using OFDM, the ieee802.11g developed as an extension of the ieee802.11a standard for data transmission in the 2.4GHz band using OFDM is being intensively studied.

Both ethernet and WLAN, which are currently widely used, use a Carrier Sense Multiple Access (CSMA) method. According to the CSMA method, it can be determined whether a channel is in use. If the channel is not in use, i.e. if the channel is idle, data is transmitted. If the channel is busy, retransmission of the data is attempted after a predetermined period of time has elapsed. A carrier sense multiple access with collision detection (CSMA/CD) method is used in a wired LAN as an improvement over the CSMA method, wherein the carrier sense multiple access with collision avoidance (CSMA/CA) method is used in packet-based wireless data communication. In the CSMA/CD method, if a collision is detected during transmission, a station interrupts transmission of a signal. In contrast to the CSMA method of previously checking whether a channel is occupied before transmitting data, in the CSMA/CD method, when a station detects a collision during transmission of a signal, the station interrupts transmission of the signal and transmits a collision signal (jam signal) to another station to inform it of the occurrence of the collision. After the collision signal transmission, the station has a random backoff period for delay and resumes transmitting signals. In the CSMA/CD method, a station does not transmit data immediately even after a channel is idle, but has a random backoff period of a predetermined duration before transmission to avoid signal collision. If signal collisions occur during transmission, the duration of the random backoff period is doubled, thereby further reducing the likelihood of collisions.

The CSMA/CA method is divided into physical carrier sensing and virtual carrier sensing. The physical carrier sensing refers to physical sensing of an active signal in a wireless medium. Virtual carrier sensing is performed such that information on the duration of medium occupation is set to a Medium Access Control (MAC) protocol data unit/Physical (PHY) service data unit (MPDU/PSDU) and transmission of data is started after the estimated duration elapses. However, if the MPDU/PSDU cannot be interpreted, the virtual carrier sensing mechanism cannot be employed.

Ieee802.11n covers both the 5GHz ieee802.11a network and the 2.4GHz ieee802.11g network, and enables stations of various data rates to coexist. In order to operate stations of various data rates using the CSMA/CA method, the stations must interpret MPDUs/PSDUs. However, some stations, that is, old stations do not often process data transmitted/received at a high rate. In this case, the legacy station cannot perform virtual carrier sensing.

Fig. 1 is a data structure of a Physical Layer Convergence Procedure (PLCP) protocol data unit (PPDU) of a related art format as defined by the ieee802.11a protocol. The PPDU includes a PLCP header and a physical layer service data unit (PSDU). The data rate field 3 and the data length field 4 are used to determine the length of the data field following the PLCP header of the PPDU. The data rate field 3 and the data length field 4 are also used to determine the time of data being received or transmitted, thereby performing virtual carrier sensing. In addition, in case that a Message Protocol Data Unit (MPDU) is correctly filtered from the received PPDU, a 'Dur/ID' field, which is one field of header fields of the MPDU, is interpreted, and the medium is virtually determined to be busy for an expected usage period of the medium. In the case where the preamble field and the signal field of the PPDU being received are only interpreted incorrectly, the medium may attempt data transmission by backing up in a predetermined extended inter-frame space (EIFS) longer than a Distributed Coordination Function (DCF) inter-frame space (DIFS), so that the smoothness of medium access of all stations available in the DCF cannot be ensured.

In a network in which existing stations using a conventional protocol or legacy stations and High Throughput (HT) stations coexist, the legacy stations may be upgraded to transmit and receive HT data. However, since the legacy stations or the legacy stations cannot interpret the "Dur/ID" field existing in the data transmitted and received by the HT stations, these stations cannot perform virtual carrier sensing.

Technical problem

Fig. 2 is a diagram illustrating that when a plurality of stations having a plurality of transmission capabilities coexist, an old station of a low transmission rate cannot perform virtual carrier sensing.

The transmitter-side high throughput station (hereinafter simply referred to as transmitter-side HT STA)101 is a station that complies with the ieee802.11n protocol and operates using a channel bonding technique or a Multiple Input Multiple Output (MIMO) technique. Channel bonding is a mechanism for transmitting data frames simultaneously on two adjacent channels. In other words, according to the channel bonding technique, since two adjacent channels are bonded during data transmission, there is a channel extension. The MIMO technique is a type of adaptive array antenna technique that electrically controls directivity using a plurality of antennas. In particular, in the MIMO system, directivity is enhanced by using a plurality of antennas by narrowing the beam width, thereby forming a plurality of transmission paths independent of each other. Therefore, the data transmission rate of the apparatus employing the MIMO system increases by as many times as the number of antennas in the MIMO system. In this regard, when data is transmitted/received using channel bonding or MIMO technology, a capable station can read the transmitted/received data, but an incapable station, i.e., an old station, cannot read the transmitted/received data. Physical carrier sensing enables a physical layer to inform a MAC layer whether a channel is busy or idle by detecting whether the physical layer has received a predetermined level of reception power. Thus, physical carrier sensing is not relevant to the interpretation of transmitted and received data.

If the transmitter-side HT STA101 transmits HT data, the receiver-side HT STA102 receives the HT data and transmits an HT acknowledgement (Ack) to the transmitter-side HT STA101 in response to the received HT data. The other HT STA 103 is able to interpret HT data and HT Ack. Assuming that the durations of transmitting and receiving the HT data and the HT Ack are set to a Network Allocation Vector (NAV), the medium may be considered busy. Then, after the NAV period elapses, the other HT STA 103 waits for the DIFS, then performs random backoff and finally transmits data.

Meanwhile, the legacy station 201 is a station that complies with the ieee802.11a, ieee802.11b, or ieee802.11g protocol but cannot interpret HT data. Thus, after the duration of the physical carrier sense check HTAck, the old station 201 waits for the duration of the EIFS and then performs a backoff. Therefore, the legacy station 201 waits longer than other stations, i.e., the transmitter-side HT STA101, the receiver-side HT STA102, and the additional HT STA 103, before being allocated a medium, thereby adversely affecting data transmission efficiency.

The IEEE802.11 standard specifies that control response frames, such as ACK, Request To Send (RTS), or Clear To Send (CTS) frames, be sent at the same data rate as the immediately preceding frame. However, if the control response frame cannot be transmitted at the same data rate as the immediately preceding frame, it must be transmitted at the highest rate in a Basic Service Set (BSS) specified in the IEEE802.11 standard. In addition, the HT data has the HT preamble and HT signal field added thereto, unlike the legacy format data, which causes an increase in overhead of the PPDU, which may cause the ACK frame to generate deteriorated performance compared to the legacy format PPDU. That is, the PPDU of the old format compliant with the ieee802.11a standard is about 20 μ s, and the newly defined HT PPDU is 40 μ s or more.

Technical scheme

Therefore, when the legacy station cannot interpret data transmitted from the HT station so that virtual carrier sensing cannot be properly performed, it is necessary to enhance the performance of network utilization by transmitting data of the legacy format without the HT preamble, for example, an ACK frame.

The present invention provides a method and apparatus for enabling a station with low performance to perform virtual carrier sensing when a plurality of stations with different capabilities coexist in a wireless network.

The invention also provides a method and equipment for transmitting the short data to achieve high efficiency.

According to an aspect of the present invention, there is provided a method of transmitting data in a wireless network, the method including: accessing a wireless network; receiving first data using channel bonding, the first data being transmitted from a station having accessed a wireless network; second data is transmitted to respective channels associated with channel bonding, the second data being either a Clear To Send (CTS) frame or a Request To Send (RTS) frame.

According to another aspect of the present invention, there is provided a wireless network apparatus, the apparatus including: a receiving unit accessing a wireless network and receiving first data transmitted from a station having accessed the wireless network using channel bonding; and a transmitting unit which transmits second data to a channel associated with channel bonding, the second data being a Clear To Send (CTS) frame or a Request To Send (RTS) frame.

Drawings

The above and other aspects of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:

FIG. 1 is a schematic illustration of a PPDU in a prior art format as defined by the IEEE802.11 protocol;

fig. 2 is a diagram showing that when a plurality of stations having a plurality of transmission capabilities coexist, an old station of a low transmission rate cannot perform virtual carrier sensing;

fig. 3 is a diagram illustrating a method of transmitting a response frame according to an exemplary embodiment of the present invention;

fig. 4A and 4B are diagrams illustrating a data structure of a PPDU transmitted and received by an HT station;

fig. 5 is a diagram illustrating a procedure in which a receiving unit transmits a legacy response frame when a transmitting unit transmits HT data using channel bonding according to an exemplary embodiment of the present invention;

fig. 6 is a diagram illustrating a procedure in which a receiving unit transmits a legacy response frame when a transmitting unit transmits HT data using channel bonding according to another exemplary embodiment of the present invention;

fig. 7 is a diagram showing a procedure in which a receiving unit transmits a legacy response frame when a transmitting unit transmits HT data without using channel bonding;

fig. 8 is a diagram illustrating an HT station transmitting legacy format data according to an embodiment of the present invention; and

fig. 9 is a flowchart illustrating a procedure in which an HT station receives an HT frame and transmits a legacy frame as a response frame according to an exemplary embodiment of the present invention.

Detailed Description

The invention and the method of practicing the invention may be understood more readily by reference to the following detailed description of exemplary embodiments and the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art, and the present invention will only be defined by the appended claims. Like reference numerals refer to like parts throughout the specification.

A method and apparatus for transmitting and receiving legacy format data in an HT wireless network will be described below with reference to a flowchart of a method according to an exemplary embodiment of the present invention. It will be understood that each block of the flowchart illustrations, and combinations of blocks in the flowchart illustrations, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart block or blocks.

These computer program instructions may also be stored in a computer usable or computer-readable memory that can direct a computer or programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instruction means that implement the function specified in the flowchart block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

Each block in the flowchart illustrations may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the blocks may occur out of the order. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

HT wireless networks according to exemplary embodiments of the present invention include wireless networks capable of transmitting and receiving HT data, such as, for example, HT wireless networks compliant with the ieee802.11n protocol, wireless networks compatible with one of the legacy format ieee802.11a, 802.11b, and 802.11c standards, and the like.

Fig. 3 is a diagram illustrating a method of transmitting a response frame according to an exemplary embodiment of the present invention.

Referring to fig. 3, there are a transmitter-side HT STA101, a receiver-side HT STA102, an additional HT STA 103, and a legacy station 201 in a wireless network. In operation S10, the transmitter-side HT STA101 transmits HT data to the receiver-side HT STA 102. As described above, HT data is transmitted at a high rate using channel bonding or MIMO technology. HT stations include stations capable of high-rate data transmission, for example, stations compliant with the IEEE802.11n protocol. Since the receiver-side HT STA102 and the further HT STA 103 can interpret HT data, they perform virtual carrier sensing. However, since the legacy station cannot interpret HT data, it cannot perform virtual carrier sensing. In contrast, the legacy station determines whether the medium is currently busy, thereby performing physical carrier sensing. After completing the transmission of the HT data, operation S11 is started, and the legacy station 201 waits for the duration of the EIFS before it performs backoff.

If the transmitter-side HT STA101 completes transmission of HT data, the procedure proceeds to operation S11. At this time, the receiver-side HT STA102 transmits the old Ack to the transmitter-side HT STA101 after the duration of a short interframe space (SIFS). The old Ack is a response frame generated according to IEEE802.11a, 802.11b, or 802.11g protocols. The legacy Ack may be transmitted to and also received from the legacy station and the HT station. After receiving each old Ack, each of the HT stations 101, 102 and 103 capable of interpreting the old response frame proceeds to operation S12, and then performs a backoff procedure after the DIFS duration.

In addition, since the legacy station 201 can interpret the legacy Ack frame but cannot interpret the HT data, it is allowed to wait for the duration of the DIFS to prevent the legacy station 201 from performing the backoff procedure in operation S12. As a result, the legacy station 201 and the HT stations 101, 102, and 103 can participate in the backoff process, thereby avoiding performance deterioration.

Fig. 4A and 4B are diagrams illustrating a data structure of a PPDU transmitted and received by an HT station.

The HT station can perform data transmission and reception in two ways, each starting with the legacy preamble, so that the legacy station can interpret data transmitted/received through the HT station with the legacy preamble.

As shown in fig. 4A, the old format PPDU30 includes an old preamble including an old short training Field (L-STF), an old long training Field (L-LTF) and an old Signal Field (L-SIG, Legacy Signal Field) and an old data ("data") payload. Similar to fig. 1, the L-SIG includes rate, reserved, length, and parity fields. The legacy format PPDU30 has a "data" payload following the L-STF, L-LTF and L-SIG fields that contain information regarding power management, signals, etc., respectively. Thus, the legacy format PPDU30 can be interpreted by both the HT station and the legacy station.

As shown in fig. 4B, when PPDU40 has an HT preamble appended to the old preamble, the HT station recognizes PPDU40 as HT data. The HT preamble includes information on HT data. The HT preamble includes: an HT signal field (HT-SIG), an HT short training field (HT-STF), and an HT long training field (HT-LTF). In detail, the HT-SIG includes a plurality of fields including: a "length" field for defining the length of HT data, an MCS field for defining a modulation and coding scheme, an advanced coding field for specifying the presence of advanced coding, a Sounding packet (Sounding packet) field for indicating whether transmission has been performed on all antennas, a number of HT-LTFs field for specifying the number of HT-LTFs in a transmitted PPDU, a short GI field for specifying a short guard interval in a data region of a frame, a scrambler INIT field for specifying an initial value of a scrambler, 20/40 for indicating whether a PPDU is converted into a signal of 20 or 40MHz bandwidth, a CRC field for error detection, and a tail field. As shown in FIG. 4B, each of the HT-SIG, HT-STF, and HT-LTF contains a specific number of bits, followed by HT data.

As shown in fig. 4B, if short data is transmitted in the HT PPDU40, it will cause a considerable increase of the HT preamble, thereby significantly increasing overhead. Therefore, in order to transmit a frame including only short data such as an Ack or a control frame, it is efficient to use the old PPDU 30. In addition, the old PPDU30 enables the old station to perform virtual carrier sensing when the old station exists in the wireless network.

Fig. 5 is a diagram illustrating a procedure in which a receiving unit transmits a legacy response frame when a transmitting unit transmits HT data using channel bonding according to an exemplary embodiment of the present invention.

When a transmitting unit selects two adjacent channels of a current channel, that is, the current channel and an immediately next channel or an immediately previous channel and the current channel, which are bonded to each other, and transmits the same content to a receiving unit, the receiving unit receives the same content and transmits an old Ack to each channel.

Fig. 6 is a diagram illustrating a procedure in which a receiving unit transmits a legacy response frame when a transmitting unit transmits HT data using channel bonding according to another exemplary embodiment of the present invention, wherein antennas 181 and 182 transmit data to different channels, unlike fig. 5.

When a transmitting unit selects two adjacent channels of a current channel, that is, the current channel and an immediately next channel or an immediately previous channel and the current channel, which are bonded to each other, and transmits the same content to a receiving unit, the receiving unit receives the same content and transmits an old Ack to one of the two channels. Unlike fig. 5, the respective antennas 181 and 182 can process different channels. The receiving unit accesses the lower and upper sub-channels using the respective antennas 181 and 182 and transmits the same old Ack frame 300. The structure of the old format frame is the same as described in fig. 4.

In response to the frame transmitted using channel bonding as shown in fig. 5 and 6, the old-format data is simultaneously transmitted to both the control channel and the extension channel, which causes the old-format data to be also received by the station in the extension channel.

Fig. 7 is a diagram illustrating a procedure in which a receiver-side HT station transmits a legacy response frame when a transmitter-side HT station transmits HT data using MIMO technology according to an exemplary embodiment of the present invention.

When the transmitter-side HT station transmits HT data using the MIMO technique, the receiver-side HT station transmits a legacy response frame via the current channel using one antenna 181. The transmitter-side HT station can receive the response frame received through the current channel. Other HT stations may interpret the legacy response frame to enable virtual carrier sensing. In addition, the old station communicating over the current channel may also interpret the old response frame to enable virtual carrier sensing. The structure of the old format frame is the same as described in fig. 4A.

As shown in fig. 5 to 7, the receiver-side HT STA102 transmits the old PPDU30 in various manners according to the transmission method used by the transmitter-side HT STA 101. The receiver-side HT STA102 can know the transmission method used by the transmitter-side HT STA101 from the MCS value in the HT-SIG field of the HT PPDU shown in fig. 4B. That is, the number of antennas or the number of spatial streams used in data transmission, the modulation scheme used, the coding rate, the guard interval, and the use or non-use of channel bonding (40Hz) can be derived from MCS values enumerated in the following table. Table 1 represents an exemplary Modulation and Coding Scheme (MCS) table.

TABLE 1

The HT station may transmit not only an Ack frame but also a control frame including short data, such as a CTS frame or an RTS frame. In the legacy format transmission, it is unnecessary to add an HT preamble to data, and the legacy station can perform virtual carrier sensing to reduce overhead.

In case that the amount of data is considerable, a PPDU of an HT format is transmitted. In the case of short data, that is, a small amount of data, such as a control frame, a PPDU of an old format is transmitted, thereby reducing the total amount of data transmitted and received in the entire wireless network and implementing a wireless network in which HT stations and old stations coexist.

The term unit, as used herein, refers to, but is not limited to, a software or hardware component or module, such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC), which performs certain tasks. A unit may advantageously be configured to reside on the addressable storage medium and configured to execute on one or more processors. Thus, a unit may include, by way of example, components, such as software components, object-based software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functionality provided for in the components and units may be combined into fewer components or modules or further separated into additional components and units. Additionally, components and units may be implemented in a communication system executing on one or more CPUs.

Fig. 8 is a diagram illustrating an HT station transmitting legacy format data according to an exemplary embodiment of the present invention. The HT station 100 includes a transmitting unit 110, a receiving unit 120, an encoding unit 130, a decoding unit 140, a control unit 150, an old transmission control unit 160, and two antennas 181 and 182. The antennas 181 and 182 receive and transmit wireless signals.

The transmission unit 110 transmits signals to the antennas 181 and 182, and the encoding unit 130 encodes data to generate signals to be transmitted to the antennas 181 and 182 through the transmission unit 110. In order to transmit signals through two or more antennas using the MIMO technology, signal data must be divided and separately encoded. Alternatively, in order to transmit a signal using signal bonding, the transmitting unit 110 selects two adjacent channels bonded to each other, the two adjacent channels including a current channel and an immediately next channel or an immediately previous channel, and transmits the signal through the bonded channels.

The receiving unit 120 receives signals from the antennas 181 and 182, and the decoding unit 140 decodes the signals received by the receiving unit 120 into data. When receiving data using MIMO technology, it is necessary to combine data transmitted through the two channels.

The old transmission control unit 160 controls short-length data to be transmitted in the old format, such as an Ack frame, a CTS frame, or an RTS frame. The control unit 150 manages and controls the exchange of information among various components of the HT station 100.

Fig. 9 is a flowchart illustrating a procedure in which an HT station receives an HT frame and transmits a legacy frame as a response frame according to an exemplary embodiment of the present invention.

The HT station accesses the wireless network in operation S301. In this case, accessing the wireless network means not only accessing the existing wireless network but also newly generating the wireless network. In an exemplary embodiment, operation S301 may include generating a Basic Service Set (BSS), for example, an Access Point (AP). Next, a first station existing in the wireless station receives first data compliant with a first protocol in operation S302. The first protocol includes a protocol for transmitting and receiving in HT format, such as the ieee802.11n protocol. Additionally, the first protocol may include a protocol that is downward compatible with the legacy format protocol.

The term "downward compatibility" as used herein means that the upgraded protocol or software is compatible with the protocols or software proposed in the past. For example, the ieee802.11n protocol may interpret data transmitted and received in the ieee802.11a, ieee802.11b, or ieee802.11g protocol, and may transmit/receive HT data compliant with the ieee802.11a, ieee802.11b, or ieee802.111g protocol. The same applies when upgraded software is available to allow interpretation and management of data generated from existing versions of software.

After receiving the first data, it is determined whether the first data is transmitted using channel bonding in operation S310. If the first data is transmitted using channel bonding (yes in operation S310), second data compliant with a second protocol is transmitted through the respective channels used in the channel bonding in operation S320. According to a second protocol, frames are transmitted that can be interpreted by legacy stations receiving the channels associated in the channel bonding. Thus, if the first protocol is compliant with IEEE802.11n, the second protocol comprises a protocol that is downward compatible with the IEEE802.n protocol, e.g., IEEE802.11a, IEEE802.11b, or IEEE802.11g, etc. The transmission process has been described above with reference to fig. 5.

If the first data is not transmitted using the channel bonding (no in operation S310), that is, if the first data is transmitted using, for example, the MIMO technique, second data compliant with the second protocol is transmitted in operation S330. The transmission process has been described with reference to fig. 6. As described above, the second protocol includes a protocol with which the first protocol is downward compatible.

The wireless network shown in fig. 8 may be a BSS with an AP or an Independent Basic Service Set (IBSS) without an AP. The second data is short data including a control frame such as Ack, CTS, RTS, etc.

Industrial applicability

The second data may be interpreted by the legacy station so that the legacy station may perform virtual carrier sensing. Thus, the use of the second data enhances transmission efficiency in a wireless network without an old station.

As described above, according to the exemplary embodiments of the present invention, when HT stations and legacy stations having different transmission capabilities coexist in a wireless network, the legacy stations may perform virtual carrier sensing.

In addition, according to an exemplary embodiment of the present invention, short data is transmitted in an old format, thereby enhancing transmission efficiency.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Accordingly, it should be understood that the above-described exemplary embodiments are for purposes of illustration only and should not be construed to limit the invention. The scope of the invention is given by the appended claims, rather than the preceding description, and all variations and equivalents which fall within the range of the claims are intended to be embraced therein.

Claims (6)

1. A method of transmitting/receiving data in a wireless network, the method comprising:

at a high-throughput station, transmitting high-throughput first data to a high-throughput station of a receiving side through a bonded channel formed by channel-bonding first and second adjacent channels; and

receiving, at the high-throughput station, second data in an old format transmitted by the high-throughput station of the receiving side via each of the first and second adjacent channels, the second data being a response frame to the first data,

wherein the legacy format complies with an IEEE802.11a standard, an IEEE802.11b standard, or an IEEE802.11g standard.

2. The method of claim 1, wherein the wireless network conforms to the IEEE802.11n standard.

3. The method of claim 1, wherein the transmitting second data comprises: the second data is separately and simultaneously transmitted via each of the first and second adjacent channels.

4. The method of claim 3, wherein the second data is transmitted through the first adjacent channel by the first antenna and the second data is transmitted through the second adjacent channel by the second antenna.

5. A wireless network device in a wireless network, comprising:

a transmitting unit that transmits high-throughput first data to a high-throughput station of a receiving side through a bonded channel formed by channel-bonding first and second adjacent channels; and

a reception unit that receives second data in an old format transmitted by the high-throughput station of the reception side via each of the first and second adjacent channels, the second data being a response frame of the first data,

an old transmission control unit controlling a response frame to be transmitted in an old format,

wherein the legacy format is compliant with an IEEE802.11a standard, an IEEE802.11b standard, or an IEEE802.11g standard, and wherein the network device is a high throughput station.

6. The wireless network device of claim 5, wherein the wireless network is compliant with the IEEE802.11n standard.