Frame format for high data throughput wireless local area

Frame format for high data throughput wireless LAN transmission

The present invention generally relates to wireless communication systems, and particularly relates to high data throughput communication in such systems.

As we all know, communication systems support wireless and wired communication between wireless and/or wired communication devices. The communication system includes from national and/or international cellular telephone systems, to the Internet, to peer-to-peer home wireless networks. It is constructed in accordance with one or more communication standards to operate each communication system. For example, a wireless communication system can follow one or more standards, including (but not limited to) IEEE 802.11, Bluetooth, Advanced Mobile Phone Service (AMPS), Digital Advanced Mobile Phone Service, Global System for Mobile Communications (GSM), Code Division Multiple Access ( CDMA), local multi-point distribution system (LMDS), multi-channel multi-point distribution system (MMDS) and/or variations thereof.

Based on the type of wireless communication system, wireless communication devices (such as cellular phones, two-way radios, personal digital assistants (PDA), personal computers (PC), notebook computers, home entertainment devices), etc. directly or indirectly communicate with other wireless communication devices . For direct communication (also called point-to-point communication), the wireless communication devices participating in the communication adjust their receivers and transmitters to the same single channel or multiple channels (for example, multiple radio frequency carriers in a wireless communication system). One) and communicate on these channel(s). For indirect wireless communication, each wireless communication device directly communicates with an associated base station (for cellular service) and/or an associated access point (for home and indoor wireless networks) through an allocated channel. In order to realize the wireless connection between wireless communication devices, the associated base stations and/or access points are connected to other base stations and/or access points through the system controller, the public switched telephone network, the Internet, or some other wide field networks. Direct communication.

For each wireless communication device participating in wireless communication, it includes a built-in radio transceiver (for example, a base station of a home and/or indoor wireless communication network, an RF modem, etc.). As we all know, the radio transceiver includes a data modulation stage, one or more intermediate frequency stages, and a power amplifier. The data modulation level follows a specific wireless communication standard to convert the original signal into a baseband signal. One or more intermediate frequency stages mix the baseband signal with one or more local oscillators to generate an RF signal. The power amplifier amplifies the RF signal before transmitting it through the antenna.

As we all know, the receiver is connected to the antenna and includes a low-noise amplifier, one or more intermediate frequency stages, a filtering stage, and a data restoration stage. The low noise amplifier receives the RF signal through the antenna. One or more intermediate frequency stages mix the amplified RF signal with one or more local oscillators to change the amplified RF signal into a baseband signal or an intermediate frequency (IF) signal. The filtering stage filters the baseband signal or the IF signal to attenuate the unwanted signal from the frequency band signal to generate a filtered signal. The data restoration stage follows a specific wireless communication standard to restore the original signal from the filtered signal.

The distribution channels or channels used for direct or indirect communication are defined by standards or standards supported by wireless communication devices. For example, IEEE 802.11(a) and (g) provide channel spectrum masks for 20 MHz Orthogonal Frequency Division Multiplexing (OFDM) channels. The standard also defines the way devices communicate in channels. For example, IEEE 802.11 (a) and (g) standards define the frame structure of communication through channels in WLAN. The frame includes a header and a variable-length data segment. The header includes a short training sequence, a long training sequence, and a signal field, which provide data rate information and data segment length.

Each receiving wireless communication device uses frame headers for signal detection, automatic gain control adjustment, density determination, frequency adjustment, timing synchronization, and channel and better frequency offset estimation. This frame format enables WLAN wireless communication devices to communicate in a very special way. However, the frame format is not suitable for higher data throughput rates, which are inversely compatible with existing WLAN equipment and different wireless channel configurations.

Therefore, a new frame format is needed to enable wireless communication devices to support multiple wireless channel configurations and/or high data throughput rates.

The frame format of the high data throughput wireless local area network transmission of the present invention fully meets the above requirements. In one embodiment, the frame format for high data throughput wireless local area network transmission includes a first header segment, a second header segment, and a variable length data segment. The first header segment includes a first training sequence, a second training sequence, and a high-throughput channel indicator, where the first training sequence is located in the first pair of subcarriers of the channel, and the second training sequence is located in the second pair of subcarriers of the channel , Where the first pair of subcarriers is a subset of the second pair of subcarriers. The second header segment includes a third training sequence in the third pair of subcarriers of the channel, where the second pair of subcarriers is a subset of the third pair of subcarriers. The variable-length data segment uses a third pair of subcarriers to transmit data.

In another embodiment, an apparatus for transmitting frames in a high-throughput unlimited local network includes a processing module, a memory, and a radio frequency transmission circuit. The memory is connected to the processor module, and the memory stores operation instructions through: generating a first header segment including a first training sequence and a high-throughput channel indicator (where the first training sequence is located in the first pair of channels) Among the subcarriers, the second training sequence is located in the second pair of subcarriers of the channel, where the first pair of subcarriers is a subset of the second pair of subcarriers), and the third pair of subcarriers is generated in the channel including the third training sequence The second header segment (where the second pair of sub-carriers is a subset of the third pair of sub-carriers), the third pair of sub-carriers are used to generate a variable-length data segment to transmit data so that the processing module prepares the frame. The radio frequency transmission circuit is connected to transmit the first header segment, the second header segment, and the variable-length data segment as a frame.

One aspect of the present invention provides a frame format for high data throughput wireless local area network transmission. The frame format includes: a first header segment including a first training sequence, a second training sequence, and a high-throughput channel indicator, wherein the first The training sequence is located in the first pair of subcarriers of the channel, and the second training sequence is located in the second pair of subcarriers of the channel, where the first pair of subcarriers is a subset of the second pair of subcarriers; in the third pair of subcarriers of the channel The second header section of the third training sequence is included in, where the second pair of subcarriers is a subset of the third pair of subcarriers; and a variable length data section that uses the third pair of subcarriers to transmit data.

In a preferred embodiment, the first header segment includes: a first training sequence corresponding to a short training sequence; a second training sequence corresponding to a long training sequence; and a signal field including a rate indicator, a short length of variable length data And the signal field indicated by the high-throughput channel.

In a preferred embodiment, the second header section includes: a channel format indicator field that identifies one of the multiple high-throughput channel formats; and a high-throughput channel training field that includes a third training sequence, where the third training sequence corresponds to One of multiple high-throughput channel formats.

A preferred embodiment is that the multiple high-throughput channel formats include at least two: those transmitted via a single antenna have 2^N40 megahertz (MHz) channels with four sub-carriers; the transmission via a single antenna has 2^M20MHz channels with two sub-carriers; the transmission via a single antenna has 2^K10MHz channel with multiple sub-carriers; the transmission via multiple antennas has 2^N40MHz channels with four sub-carriers; the transmission via multiple antennas has 2^M20MHz channels with two sub-carriers; and a multi-antenna transmission with 2^K10MHz channel of sub-carriers.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through a single antenna with 2^NIn the case of 40 MHz channels with four sub-carriers, the third training sequence includes: 2 using 40 MHz channels^NThe final channel prediction for each sub-carrier.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through a single antenna with 2^MWhen the 20MHz channel of two subcarriers is used, the third training sequence includes: 2^MThe final channel prediction for each sub-carrier.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through a single antenna with 2^KIn the case of 10 MHz channels with two sub-carriers, the third training sequence includes: 2 using 10 MHz channels^KThe final channel prediction for each sub-carrier.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through multiple antennas with 2^NIn the case of a 40MHz channel with four subcarriers, the third training sequence includes:

2 of the 40 MHz channel using the first transmission via multiple antennas^NThe first final channel prediction of sub-carriers.

2 using the 40 MHz channel of the second transmission via multiple antennas^NThe second final channel prediction of sub-carriers.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through multiple antennas with 2^MIn the case of 20 MHz channels of two subcarriers, the third training sequence includes:

2 using the 20 MHz channel of the first transmission via multiple antennas^MThe first final channel prediction of sub-carriers.

2 using the 20 MHz channel of the second transmission via multiple antennas^MThe second final channel prediction of sub-carriers.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through multiple antennas with 2^KIn the case of 10 MHz channels of 10 sub-carriers, the third training sequence includes:

2 of the 10 MHz channel using the first transmission via multiple antennas^KThe first final channel prediction of sub-carriers.

2 of the 10 MHz channel using the second transmission via multiple antennas^KThe second final channel prediction of sub-carriers.

One aspect of the present invention provides a device for transmitting frames in a high-throughput wireless local area network. The device includes: a processing module; : Generate a first header segment including a first training sequence and a high-throughput channel indicator, where the first training sequence is located in the first pair of subcarriers of the channel, and the second training sequence is located in the second pair of subcarriers of the channel, where The first pair of subcarriers is a subset of the second pair of subcarriers); a second header segment including the third training sequence is generated in the third pair of subcarriers in the channel, where the second pair of subcarriers makes the third pair of subcarriers Subset; use the third pair of subcarriers to generate variable-length data segments to transmit data to prepare the processing module for the frame; and connect the radio frequency transmission circuit to transmit the first header segment, the second header segment, and the Variable length data segment.

In a preferred embodiment, the first header segment includes: a first training sequence corresponding to a short training sequence; a second training sequence corresponding to a long training sequence; and a signal field including a rate indicator, a short length of variable length data And the signal field indicated by the high-throughput channel.

In a preferred embodiment, the second header section includes: a channel format indicator field that identifies one of the multiple high-throughput channel formats; and a high-throughput channel training field that includes a third training sequence, where the third training sequence corresponds to One of multiple high-throughput channel formats.

A preferred embodiment is that the multiple high-throughput channel formats include at least two: those transmitted via a single antenna have 2^N40 megahertz (MHz) channels with four sub-carriers; the transmission via a single antenna has 2^M20MHz channels with two sub-carriers; the transmission via a single antenna has 2^K10MHz channel with multiple sub-carriers; the transmission via multiple antennas has 2^N40MHz channels with four sub-carriers; the transmission via multiple antennas has 2^M20MHz channels with two sub-carriers; and a multi-antenna transmission with 2^K10MHz channel of sub-carriers.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through a single antenna with 2^NIn the case of 40 MHz channels with four sub-carriers, the third training sequence includes: 2 using 40 MHz channels^NThe final channel prediction for each sub-carrier.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through a single antenna with 2^MWhen the 20MHz channel of two subcarriers is used, the third training sequence includes: 2^MThe final channel prediction for each sub-carrier.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through a single antenna with 2^KIn the case of 10 MHz channels with two sub-carriers, the third training sequence includes: 2 using 10 MHz channels^KThe final channel prediction for each sub-carrier.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through multiple antennas with 2^NIn the case of a 40MHz channel with four subcarriers, the third training sequence includes:

2 of the 40 MHz channel using the first transmission via multiple antennas^NThe first final channel prediction of sub-carriers.

2 using the 40 MHz channel of the second transmission via multiple antennas^NThe second final channel prediction of sub-carriers.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through multiple antennas with 2^MIn the case of 20 MHz channels of two subcarriers, the third training sequence includes:

2 using the 20 MHz channel of the first transmission via multiple antennas^MThe first final channel prediction of sub-carriers.

2 using the 20 MHz channel of the second transmission via multiple antennas^MThe second final channel prediction of sub-carriers.

The preferred embodiment is when one of the multiple high-throughput channel formats is transmitted through multiple antennas with 2^KIn the case of 10 MHz channels of 10 sub-carriers, the third training sequence includes:

2 of the 10 MHz channel using the first transmission via multiple antennas^KThe first final channel prediction of sub-carriers.

2 of the 10 MHz channel using the second transmission via multiple antennas^KThe second final channel prediction of sub-carriers.

FIG. 1 is a functional block diagram showing a communication system 10 including a plurality of base stations and/or access points 12-16, a plurality of wireless communication devices 18-32, and a network hardware part 34. The wireless communication devices 18-32 may be notebook hosts 18 and 26, personal digital assistants 20 and 30, personal hosts 24 and 32, and/or cellular phones 22 and 28. The wireless communication device will be described in detail below in conjunction with FIG. 2.

Base stations or access points 12-16 are connected to network hardware 34 through local network connections 36, 38, and 40. The network hardware 34 (which can be a router, a switch, a bridge, a modem, a system controller, etc.) provides a wide field network connection 42 for the communication system 10. Each base station or access point 12-16 has an associated antenna or antenna array to communicate with wireless communication devices in the zone through one or more configuration channels in one or more frequency bands. Generally, wireless communication devices register with specific base stations or access points 12-14 to receive services from the communication system 10. For direct communication (ie point-to-point communication), the wireless communication device communicates directly through the channel allocated by the configuration channel.

Generally speaking, base stations are used in cellular phone systems and similar systems, while access points are used in home or indoor wireless networks. Regardless of the special type of communication system, each wireless communication device includes a built-in radio device and/or is connected to a radio device. The radio equipment includes high linearity amplifiers and/or programmable multi-stage amplifiers, which are disclosed in the present invention to enhance performance, reduce costs, and/or expand broadband applications.

Fig. 2 is a functional block diagram showing a wireless communication device including a main device 18-32 and a related radio device 60. For a cellular phone, the radio 60 is a built-in component. For a personal digital assistant, a notebook host and/or a personal computer host, the radio device 60 can be a built-in or external connection component.

As shown in the figure, the main device 18-32 includes a processing module 50, a memory 52, a wireless interface 54, an input interface 58, and an output interface 56. The processing module 50 and the memory 52 execute corresponding instructions generally processed by the host device. For example, for a cellular phone master device, the processing module 50 complies with a specific cellular phone standard to perform corresponding communication functions.

The wireless interface 54 enables data to be received from and transmitted to the wireless device 60. For data (such as input data) received from the radio device 60, the wireless interface 54 provides the data to the processing module 50 for further processing and/or routing to the output interface 56. The output interface 56 provides a connection to an output display device (such as a display, a monitor, a speaker, etc.) so that the received data can be displayed. The wireless interface 54 also provides data from the processing module 50 to the wireless device 60. The processing module 50 receives output data from an input device (such as a keyboard, a keypad, a microphone, etc.) through the input interface 58 or generates data by itself. For the data received through the input interface 58, the processing module executes the corresponding main function on the data and/or routes it to the radio device 60 through the wireless interface 54.

The radio equipment 60 includes a host interface 62, a digital receiver processing module 64, an analog-to-digital converter 66, a filter/gain module 68, an IF hybrid down conversion stage 70, a receiver filter 71, a low noise amplifier 72, and a transmitter /Receiver switch 73, digital-to-analog converter 78, filter/gain module 80 and IF hybrid up-conversion stage 82, power amplifier 84, transmit filter module 85 and antenna 86. The antenna 86 may be a single antenna shared by the transmitting and receiving paths controlled by the Tx/Rx switch 73, or an independent antenna including the transmitting path and the receiving path. The implementation of the antenna depends on the specific communication standard followed by the wireless communication device.

The digital receiver processing module 64 and the digital transmitter processing module 76 combined with the operating instructions stored in the memory 75 execute the digital receiver baseband function and the digital transmitter baseband function, respectively. Digital receiver functions include (but are not limited to) digital IF-to-baseband conversion, demodulation, decoding, and/or descrambling. The functions of the digital receiver include (but are not limited to) scrambling, encoding, modulation and/or digital baseband-IF conversion. The digital receiver and transmitter processing module 64 can be implemented using a common processing device, independent processing devices, and multiple processing devices. The processing equipment can be a microprocessor, a microcontroller, a digital signal processor, a microcomputer, a central processing unit, a field programmable gate array, a programmable logic device, a state machine, a logic circuit, an analog circuit, a digital circuit, and/or Any device that operates signals (analog and/or digital) based on operating instructions. The memory 75 may be a single-memory device or a multi-memory device. The memory device can be read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory and/or any device that stores digital information. It should be noted that when the processing module 64 and/or 76 implements one or more functions through a state machine, an analog circuit, a digital circuit, and a logic circuit, the memory storing the corresponding operation instructions is embedded in the memory including the state machine and the analog circuit. , Digital circuits and/or logic circuits.

In operation, the radio device 60 receives output data 94 from the host device through the host interface 62. The host interface 62 sends the output data 94 to the digital transmitter processing module 76, which complies with a specific wireless communication standard (for example, IEEE 802.11 Bluetooth, etc.) to process the output data 94 to generate digital transmission format data 96. The digital transmission format data 96 is a digital baseband signal or a digital low IF signal, where the low IF is generally in the frequency range of 100 kilohertz to several megahertz. In addition, the digital transmission format data 96 is based on the channel width of the RF channel, and the data 96 is finally transmitted on the RF channel. For example, the channel width can be 10 MHz, 20 MHz, or 40 MHz. Continuing the above example, if the channel is an OFDM (Orthogonal Frequency Division Multiplexing) channel, a 10 MHz width channel includes 32 subcarrier frequencies, a 20 MHz width channel includes 64 subcarrier frequencies, and a 40 MHz width channel includes 128 subcarrier frequencies. , Where the number of subcarriers used by each channel is based at least in part on the spectrum mask configured for the channel. The configuration of the spectrum mask will be described in more detail in conjunction with Figure 3 to Figure 6.

The digital-to-analog converter 78 converts the digital transmission format data 96 from a digital field to an analog field. The filter/gain module 80 filters and/or adjusts the gain of the analog signal before providing it to the IF mixing stage 82. The IF mixing stage 82 converts analog baseband or low IF signals into RF signals based on the transmitter local oscillation 83 provided by the local oscillation module 74. The power amplifier 84 amplifies the RF signal to produce an output RF signal 98. The transmitting filter module 85 filters the output RF signal 98. The antenna 86 transmits the output RF signal 98 to a destination device (such as a base station, an access point, and/or other wireless communication devices). It should be noted that the band pass field of the filters 80 and 85 depends on the spectrum mask configured for RF transmission, and the configured spectrum mask is determined by the digital transmitter processing module 76.

The radio device 60 also receives an input RF signal 88 through the antenna 86, and the input RF signal 88 is transmitted by a base station, an access point, or other wireless communication devices. The Tianxun love girl 86 provides the input RF signal 88 to the receiver filter module 71 through the Tx/Rx switch 73, wherein the Rx filter 71 band-pass filters the input RF signal 88. The Rx filter 71 provides the filtered RF signal to the low noise amplifier 72, which amplifies the signal 88 to produce an amplified input RF signal. The low noise amplifier 72 provides the amplified input RF signal to the IF mixing module 70. The IF mixing module 70 directly converts the amplified input RF signal into an input low IF signal or baseband based on the receiver local vibration 81 provided by the local oscillation module 74 Signal. The down conversion module 70 provides the input low IF signal or baseband signal to the filter/gain module 68. The filter/gain module 68 filters and/or gains input low IF signals or input baseband signals to generate filtered input signals. It should be noted that the band pass field of the filters 71 and 68 depends on the spectrum mask configured for RF transmission, and the spectrum configuration of this configuration is determined by the receiver processing module 64.

The analog-to-digital converter 66 converts the filtered input signal from an analog field to a digital field to generate data 90 in a digital reception format. The digital receiver processing module 64 decodes, descrambles, and/or demodulates the digital reception format data 90 to retrieve the input data 92 in accordance with the specific wireless communication standard realized by the specific channel width of the radio device 60 and the channel. The host interface 62 provides the retrieved input data 92 to the host device 18-32 via the wireless interface 54.

Those of ordinary skill in the art can understand that one or more integrated circuits may be used to implement the wireless communication device of FIG. 2. For example, the main device can be implemented on one integrated circuit, the digital receiver processing module 64, the digital transmitter processing module 76 and the memory 75 can be implemented on the second integrated circuit, and the third integrated circuit can be implemented The remaining components of the radio equipment and the antenna 86 are implemented. As another example, the radio device 60 can be implemented on a single integrated circuit. As another example, the processing module 50, the digital receiver, and the transmitter processing modules 64 and 76 of the main device may be common processing devices, which may be implemented on a single integrated circuit. In addition, the memories 52 and 75 can be implemented on a single integrated circuit and/or the same integrated circuit as the common processing module 50, digital receiver, and transmitter processing modules 64 and 76 of the main device.

Figure 3 is a schematic diagram showing multiple frequency bands (eg, frequency band 1 to frequency band N) that are defined by government agencies for specific wireless applications. For example, for the United States, the Federal Communications Commission (FCC) defines frequency bands for specific applications and applications required by FCC licenses (for example, wireless transmission, television transmission, etc.), and defines frequency bands that can be used in different applications without a license. . For example, the FCC has defined some frequency bands in the radio spectrum as unlicensed. These unlicensed frequency bands include 902-928 MHz, 2.4-2.483 GHz, and 5.75-5.85 GHz, which are collectively referred to as the ISM (Industrial, Scientific, and Medical Equipment) frequency band. Today, the ISM band is used in indoor and system applications (e.g., barcode readers), industrial microwave ovens, wireless patient monitors, and wireless local area networks (WLAN).

Figure 4 is a schematic diagram showing a specific frequency band divided into multiple channels. According to the present invention, the channel bandwidth of each channel is selectable. In this way, for a given frequency band, the number of channels varies based on the selected channel width. For example, in one embodiment of the present invention, the channel width can be selected following IEEE 802.11(a) or (g), where IEEE 802..11(a) provides operating specifications for wireless LANs in the 5.15-5.35 GHz frequency band. Generally speaking, the specified modulation method is based on Orthogonal Frequency Division Multiplexing (OFDM). For 802.11(a), OFDM divides the 5.15-5.35 GHz frequency band into 18 channels with a width of 10 MHz. The center frequency is 5.165 GHz, and the center frequencies of the other 11 channels increase by 10 MHz from there. In another embodiment of the present invention, the 5.15-5.35 GHz frequency band is originally divided into three 40 MHz width channels, and the center frequencies are respectively at 5.21, 5.25, and 5.29 GHz. The same channel width selectivity can also be applied to the 2.4-2.482 GHz frequency band operated by IEEE 802.11(g), other frequency bands operated by the IEEE 802.11 standard, and/or other wireless communication standards. The channel width selectivity provides higher data throughput (for example, at least IEEE 802.11(g) twice the data rate), application diversity, and/or enabling a single wireless communication device to support multiple wireless standards promulgated by different standard entities (including government agencies).

FIG. 5 is a schematic diagram showing the wireless transmitter section 120 transmitting frames 126A, 126B to the wireless receiver section 122 through a radio frequency (RF) channel. The wireless transmitter section 120 is located in the wireless communication device, and corresponds to the digital transmitter processing module 76, the digital-to-analog converter 78, the filter/gain module 80, the up-conversion module 82, and the power Amplifier 84 and transmit filter module 85. The wireless receiver section 122 is another wireless communication device, which corresponds to the digital receiver processing module 64, the analog-to-digital converter 66, the filter/gain module 68, and the down-conversion module 70 of the wireless communication device of FIG. Low noise amplifier 72 and receiving filter module 71. Channel 124 can be any one of the channels shown in Figure 3, and there is a patent application pending at the same time (serial number 60/524528, attorney's note number BP3400, invention name "configurable used in high data throughput wireless communication Spectrum mask", the filing date is 11/24/03) any spectrum mask configuration described in.

The format of the frames 126A and 126B includes a first header segment 128, a second header segment 130, and a variable length data segment 132. The first header training segment 128 includes a first training sequence 134, a second training sequence 136, and a throughput channel indicator 138. The second header section 130 includes a third training sequence 140. In one embodiment, the first training sequence 134 and the second training sequence 136 correspond to the short header training sequence and the long header training sequence following IEEE 802.11a or g. When the transmitting radio device needs to use the high-throughput channel configuration, the high-throughput channel indication 138 is set. If the high-throughput channel indication is not set, the second header section 130 will be ignored, and the frame will be arranged like a traditional wireless local area network conforming to IEEE 802.11a, b, g, etc.

The high-throughput channel indication 138 is used to implement the third training sequence 130 of the third header segment to adjust the wireless receiver according to a specific channel configuration. The variable length data segment 132 includes a guard interval and an associated data field. The format of the frame 126 will be described in more information in conjunction with FIG. 6 below.

Figure 6 shows frame 126 in more detail. As shown in the figure, the first header segment 128 includes a first training sequence 134, a second training sequence 136, and a signal field.

The first training sequence 134 includes 10 short training sequences, which only use a part of the subcarriers of a specific channel. For example, the channel configuration may be a 20 MHz channel bandwidth with 64 subcarriers. The first training sequence 134 nearly uses 12 of the 52 data subcarriers to transmit the corresponding short training sequence. The second training sequence 136 includes 2 long training sequences, which use all 52 data subcarriers of 20 MHz and 64 subcarrier channels.

The signal field includes a guard interval (GI) screen including 24 bits of information. The first 4 bits correspond to the data transmission rate, the next bit indicates the high throughput channel indicator 138, the next 12 bits correspond to the length of the variable-length data segment 132, and the 17th bit corresponds to the parity of the data. The next 6 bits correspond to the end of the signal.

If the high throughput channel indication 138 is not set, the receiving radio device will configure itself based on the preset value or the first channel configuration (using 64 subcarriers as the 20 MHz bandwidth channel currently defined in IEEE 802.11a and/or g). However, if the high throughput channel indication 138 is set, the receiver is able to select the channel configuration, and it will start decoding the second header.

The second header section 130 includes a channel format identification field and a plurality of training sequences 140-141. The channel identification field includes additional 4 bits for rate information, 5 bits for channel configuration information, 12 bits for indicating the training matrix, and the remaining 3 bits are reserved. Those of ordinary skill in the art can understand that, according to the bit rate of high-throughput data, the channel configuration of high-throughput data transmission, the hierarchical antenna arrangement, and the channel matrix, the 24 bits of the channel format identification field can be configured in different ways. The information is transmitted to the receiving radio equipment to produce dual RF transmission on a single channel.

Once the channel format identification field has been processed, the receiving radio device reconfigures itself based on the channel configuration and data rate. After completing its own reconfiguration, the radio device receives the third training sequence 140 through the nth training sequence 141 (which corresponds to the number of transmit antennas) that uses most of the subcarriers according to the new channel configuration. The channel configuration will be described in more detail below in conjunction with FIG. 7.

The rate bits in the first header and the second header can be combined to provide 8-bit rate information and/or in the case of dual communication on a single path, the rate bits in the first header and the second header can be provided separately. Indicates the rate of individual communication. The variable length data segment 132 includes multiple data segments and associated guard intervals (GI).

Figure 7 is a table showing a variable channel configuration that can be used to transmit high data throughput communications. The channel configuration table includes a bit string that identifies specific channel configuration and configuration information, including channel bandwidth, the number of sub-carriers per channel, rate decoding (that is, the rate bits in each header segment used in connection or separately), and space-time Encoding (ie, the number of channel paths supported by a specific RF channel). In this example, there are three channel bandwidth options: 10 MHz, 20 MHz, and 40 MHz. They can be used in multiple frequency bands (including, but not limited to 2.4000-2.4835 GHz, 2.471-2.497 GHz, 5.15-5.25 GHz, 5.25-5.35 GHz, 5.47-5.725 GHz, 5.725 GHz-5.825 GHz, 4.9-5.3 GHz and 5.85-5.925 GHz). The default work of the wireless communication system of the present invention is to work in IEEE 802.11a or g. As we all know, the channel configuration of 802.11a and/or g includes a 20 MHz channel bandwidth using 64 subcarriers, of which the RF channel only supports one path. Therefore, the default channel configuration is not in the channel configuration information in the second header section.

However, if a 20 MHz bandwidth channel with space-time coding supporting two paths is used through a single RF channel, higher data throughput can be obtained. In an example, the rates of the two channels are the same, which corresponds to a rate decoding of 0, which allocates 8 bits (the 4 bits of the first header segment and the 4 bits of the second header segment are combined into an 8-bit code). If the rates of the two paths in space-time coding are different, the rate is decoded to 1. In this example, the 4-bit rate information in the first header segment and the 4-bit rate information in the second header segment are used to indicate the rates of other channel paths.

The table further shows that the 40 MHz channel bandwidth includes 128 subcarriers and supports one or two paths per channel. Similarly, the 10 MHz channel bandwidth has 64 sub-carriers and supports one or two channel paths.

Figure 8 is a schematic diagram showing a first training sequence 114 based on a 20 MHz channel and 64 subcarriers per channel. The training sequence is repeated twice, and only 12 subcarriers out of all 64 subcarriers are used. In one embodiment, each of the 12 subcarriers transmits a 1+j or^-1^-The code element of j. In this part of the header, the receiver uses the first training sequence 114 as signal detection, and once a possible signal is detected, adjust the gain setting in the receiver and determine whether any hierarchical antenna has been selected. In addition, in the later part of the first training sequence 114, frequency adjustment, offset estimation, and/or timing synchronization may be roughly performed.

FIG. 9 is a schematic diagram showing a second training sequence 116 of a 20 MHz channel bandwidth using 64 subcarriers. Of the 64 subcarriers, 53 are used in the second training sequence 116. Except that the 0th subcarrier transmits a zero value, each subcarrier transmits a +1 or^-1 code element. When the receiver detects the second training sequence 116, it performs channel and precision frequency adjustment and/or precision offset adjustment.

FIG. 10 is a schematic diagram showing a third training sequence 120 that uses single space-time channel division and includes 128 subcarriers. In this example, the header uses the 105th to 119th carriers of 128 subcarriers (where the symbol can be +1 or^-1) To transmit the training sequence. At this stage, the receiver again performs channel and precise frequency adjustment corresponding to the 128 sub-carrier configuration of the 40 MHz channel of the channel. In addition, the receiver can perform precise offset adjustments for specific channel configurations.

Figure 11 is a schematic diagram of an optional third training sequence 120, where the channel configuration is a 10 MHz channel with 64 subcarriers. In this example, the third training sequence 120 uses 53 subcarriers out of 64 possible subcarriers. In this frame, the receiver performs channel and precise frequency adjustment and/or precise offset adjustment for a 10 MHz bandwidth, 64 sub-carrier channels. It should be noted that the symbols used in the training sequence can be +1 or^-1。

FIG. 12 is a schematic diagram of the third training sequence 120, in which the channel configuration is a 40 MHz channel with 128 subcarriers and space-time coding is used to generate 2 paths (path A and path B). In this example, each path has its own corresponding training sequence, which uses 105-119 subcarriers among the possible 128 subcarriers. The symbols in each subcarrier can be +1 or^-1. In this time frame, the receiving radio device performs channel and precision frequency adjustment and/or precision offset adjustment for each path of the 40 MHz channel.

Those of ordinary skill in the art can understand that the terms "sufficient" and "approximately" used herein provide industry-accepted tolerances for their corresponding terms. The tolerance accepted in the industry ranges from less than 1% to 20% and corresponds to (but not limited to) component values, integrated circuit processing variations, temperature variations, rise and fall times, and/or thermal noise. Those of ordinary skill in the art can further understand that the term "working connection" as used herein includes direct connection and indirect connection through other elements, components, circuits or modules. For indirect connection, intervening elements, components, circuits or The module does not adjust the signal information but only adjusts its current level, voltage level and or power level. Those of ordinary skill in the art can also understand that inferred connection (connecting one component to another by inference) has the same connection mode as "working connection": it includes direct and indirect connections between two elements. Those of ordinary skill in the art can further understand that the term "smoothly compared" used herein indicates two or more components or parts. The comparison between signals etc. provides the required relationship. For example, when the required relationship is that the absolute value of signal 1 is greater than that of signal 2, when the absolute value of signal 1 is greater than that of signal 2, or when the absolute value of signal 2 is smaller than that of signal 1, you can Get a smooth comparison.

The above description provides a new frame format and radio transmitter for high data throughput wireless local area network transmission that is backward compatible with traditional systems. Those of ordinary skill in the art can understand that other embodiments can be obtained through the teaching of the present invention without departing from the scope of protection of the claims.

Figure 1 is a schematic block diagram of the wireless communication system of the present invention; Figure 2 is a schematic block diagram of the wireless communication device of the present invention; Figure 3 is a schematic diagram showing the frequency bands that can be used in the present invention; Figure 4 is a schematic diagram showing the present invention Channel division of frequency bands; Figure 5 is a schematic diagram of frame transmission through an RF channel according to an embodiment of the present invention; Figure 6 is a schematic diagram of a frame format according to an embodiment of the present invention; Figure 7 is a schematic diagram of a channel configuration according to an embodiment of the present invention; A schematic diagram of the first training sequence of the present invention; FIG. 9 is a schematic diagram of the second training sequence of the present invention; FIG. 10 is a schematic diagram of the third training sequence of the present invention; FIG. 11 is a schematic diagram of an optional third training sequence of the present invention; It is a schematic diagram of another third training sequence of the present invention.