CN100558103C - Long Training Sequences for Multiple-Input Multiple-Output Wireless LAN Systems - Google Patents

Abstract

A method for configuring multiple-input multiple-output (MIMO) wireless communication, first by generating multiple preamble information on multiple antennas. Each preamble message includes the carrier sense sequence at the legacy transmit rate, the first channel sounding at the legacy transmit rate, the signal domain at the legacy transmit rate, and the L-1 channel at the MIMO transmit rate Probes, where L corresponds to the number of channel probes. The method proceeds by simultaneously transmitting multiple preamble messages on multiple transmit antennas.

Description

Long Training Sequences for Multiple-Input Multiple-Output Wireless LAN Systems

This patent application claims priority to an unpending provisional patent application of the same title as this non-provisional patent application, provisional application number 60/562,168, provisional filing date 4/14/04.

technical field

The present invention relates generally to wireless communication systems, and more particularly to interoperability between next generation and legacy versions of wireless terminals within wireless communication systems.

Background technique

Communication systems are known to support wireless and wired communication between wireless and wired communication devices. These communication systems range from national and/or international mobile phone systems, to the Internet, to intra-home peer-to-peer wireless networks. The construction and operation of various types of communication systems follow one or more communication standards. For example, wireless communication systems need to comply with one or more standards, including but not limited to the following standards, IEEE 802.11 (Wireless Local Area Networks WLANs), Bluetooth, Advanced Mobile Phone Service (AMPS), Digital AMPS, Global System for Mobile Communications (GSM) , Code Division Multiple Access (CDMA), Localized Multipoint Distribution System (LMDS), Multichannel Multipoint Distribution System (MMDS) and/or variants thereof.

Depending on the type of wireless communication system, a wireless device such as a mobile phone, two-way wireless receiver, personal digital assistant (PDA), personal computer (PC), laptop, home entertainment device, etc. communicates directly or indirectly with other wireless Device communication. For direct communication (such as known as point-to-point communication), the devices participating in the wireless communication tune the receiver and transmitter to the same channel (for example, one of the multiple radio frequency (RF) carriers of the wireless communication system), and Communication on the channel. For indirect wireless communication, each wireless communication device directly communicates with an associated base station (eg, such as a mobile service) and/or an associated access point (eg, a wireless network in a home or building) through a designated channel. In order to complete the communication connection between wireless communication devices, related base stations and/or related access points directly communicate with each other through a system controller, a public switched telephone network, the Internet or other wide area networks.

For each wireless communication device participating in wireless communication, including built-in wireless transceivers (that is, receivers and transmitters), or associated wireless transceivers with connections (such as base stations for wireless communication networks in homes or buildings, RF modem wait). As is known, a transmitter includes a data modulation stage, one or more intermediate frequency stages and a power amplifier. The data modulation stage converts the raw data into a baseband signal according to a specific wireless communication standard. 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 sending it through the antenna.

As is known, a receiver is connected to an antenna and includes a low noise amplifier, one or more intermediate frequency stages, filtering stages and a data recovery stage. The LNA receives the incoming RF signal from the antenna and amplifies it. One or more intermediate frequency stages mix the amplified RF signal with one or more local oscillators to convert the amplified RF signal to a baseband signal or an intermediate frequency (IF) signal. The filter stage filters either the baseband signal or the IF signal to attenuate unwanted signals outside the signal band to produce a filtered signal. The data restoration stage restores the filtered signal to the original data according to a specific wireless communication standard.

Furthermore, the data recovery stage performs a number of operations in converting the filtered signal into recovered data. These operations include: for IEEE 802.11a or IEEE 802.11g compliant receivers, guard interval removal, fast Fourier transform, demapping and clipping, de-interleaving, and decoding. Decoding uses a channel estimation (channel estimation) to generate recovered data from the deinterleaved data. According to IEEE 802.11a and/or IEEE 802.11g standards, a frame includes a short training sequence (STS), a long training sequence (LTS), a signal field and multiple data fields. IEEE 802.11a and/or IEEE 802.11g further specify that channel estimation is done during the long training sequence. Once the channel estimate is determined, it is used for the rest of the frame.

Currently, next-generation WLANs are being developed with the coexistence of IEEE 802.11a, IEEE 802.11b, and/or IEEE 802.11g base stations (STAs) and access points (APs). An anticipated next-generation system will include a multiple-input multiple-output (MIMO) interface (802.11n). MIMO interfaces for next-generation systems must be interoperable with legacy versions of STAs and base stations. Interoperability requires legacy devices to be able to recognize new generation transmissions and respond accordingly. These common uses include at least two specific operations. In the first operation, an access point can support both legacy and next-generation STAs. In the second operation, legacy and next generation STAs can share channels, such as joint channel/overlapping BSS. In each of the above cases, the Physical Layer Convergence Procedure (PLCP) header must allow 802.11a/b/g STAs to recognize next-generation transmissions, split channel clear assessment (CCA) indications, or use protection mechanisms such as request-to-send/clear-to-send (RTS/CTS) or clear to send (CTS-to-sent) steps to avoid conflicts during transmission. In each of these cases, the NextGen preamble information must be backward compatible to ensure that legacy version devices can recognize NextGen device transmissions.

Therefore, there is a demand for the preamble information of the next-generation device, which needs to ensure that the device of the legacy version can be identified, and at the same time support the needs of the next-generation device.

Contents of the invention

These and other requirements are fully met by the long training sequence of the MIMO WLAN system of the present invention. In one embodiment, a method of configuring multiple-input multiple-output (MIMO) wireless communication is provided to generate multiple preamble information for multiple transmit antennas. Each of the plurality of preamble information includes a carrier detect sequence at a legacy transmission rate, a first channel sounding, a signal field, and a Z-1 channel sounding at a MIMO transmission rate. The method then simultaneously transmits multiple preambles through multiple transmit antennas.

In another embodiment, a method for generating a training symbol sequence for a multi-output OFDM RFIC first generates M+1 OFDM symbols, where M represents the output number of RF. The method then selects the symbols on the second to Mth antennas at the first time instant as the symbols transmitted on the first antenna at the first time instant multiplied by a real scalar value with the first column of the MxM unary matrix a symbol. The method then selects the symbols transmitted on the first to Mth antennas at the third to (M+1)th time instants as the symbols transmitted on the first antenna at the first time instant corresponding to the second to Mth columns of the same unary matrix The first sign of multiplication. The method then selects the symbols transmitted on the first to Mth antennas at the second time instant as the first symbols to be transmitted on the first to Mth antennas.

In another embodiment, a method for generating a training symbol sequence for a multi-output OFDM RF receiver, the method first generates p*M OFDM symbols, where M is the number of RF outputs, and p is an integer greater than 1 . The method then selects the symbols transmitted on the second to Mth antennas at the first instant as the symbols transmitted on the first antenna at the first instant multiplied by a real scalar value with the first column of the MxM unary matrix first symbol. The method then selects the symbols transmitted on the first to Mth antennas at the second to Mth time instants as the first symbol. The method then selects the symbols transmitted on each antenna at the (M+1)th to p*Mth time instants as (p-1) copies of the first M symbols transmitted on the M antennas.

In a further embodiment, a method of calculating an estimated NxM channel matrix for each J subcarrier receiving OFDM transmission information, where N is the number of antennas desired to transmit, and M is the number of receiving antennas, the method first The first K samples in each block of I+K are removed, I>=J samples. The method then applies a discrete Fourier transform on the remaining I samples of each block. The method then selects from each output block of I samples the J subcarriers identified at the transmitter activated with non-zero symbols. The method then forms an NxM matrix at each output on J subcarriers, each column of the matrix corresponds to the output from the Jth subcarrier at M consecutive time instants on the receiver antenna, and each row of the matrix corresponds to the output from all The jth subcarrier of the output on the N receive antennas. The method then post-multiplys the MxM unary matrix by the Hammett transpose used to multiply the symbols transmitted on the first transmit antenna. The method proceeds by multiplying the resulting NxM matrix by the complex conjugate of the first symbol obtained by transmitting on the first transmit antenna.

In a further embodiment, a radio frequency integrated circuit (RFIC) transmitter includes a baseband processing module and a radio frequency transmitter section. The baseband processing module is operatively connected to generate a plurality of preamble messages. A radio frequency (RF) transmitter section transmits a plurality of preamble messages at radio frequency through the operative connection of the plurality of antennas. The baseband processing module generates a number of preamble messages including carrier sense sequence at legacy transmit rate, first channel sounding at legacy transmit rate, signal field at legacy transmit rate, and L-1 at MIMO transmit rate Channel detection, where L corresponds to the number of channel detections.

According to an aspect of the present invention, there is provided a method of configuring multiple-input multiple-output (MIMO) wireless communication, the method comprising:

generating a plurality of preamble information for a plurality of transmit antennas, each preamble information including:

Carrier detect sequence at legacy transmit rate;

First channel sounding at legacy send rate;

signal fields at legacy send rates; and

Multiple channel sounding at MIMO transmit rates; and

The plurality of preamble information is simultaneously transmitted through the plurality of transmitting antennas.

Advantageously, the MIMO transmission rate comprises a legacy version transmission rate.

Advantageously, the method further comprises generating the signal field by:

Indicates the frame length of MIMO wireless communications such that legacy wireless communications devices are set to avoid collisions for the duration of MIMO wireless communications; and

Set reserved bits to indicate MIMO wireless communication.

Advantageously, the method further comprises generating a signal field using reserved bits by:

Use the rate bits in the signal field to indicate the transmit antenna configuration and preamble information configuration.

Advantageously, the method further comprises generating the signaling field using reserved bits by:

The fictitious rate is specified in the rate bit and the length bit of the signal field, wherein the fictitious rate indicates the frame length of the MIMO wireless communication, the configuration of the transmitting antenna and the configuration of the preamble information.

Advantageously, the method further comprises, using a reserved bit setting:

Use a default rate to specify the MIMO wireless communication frame length, transmit antenna configuration and preamble information configuration.

Advantageously, the sending rate of the legacy version includes:

A weighting factor is applied on each of the first channel sounding and signal fields.

Advantageously, generating a plurality of channel soundings comprises:

Selecting symbols to be transmitted on the first to Mth antennas of the plurality of antennas at the first time instant as a multiplied by a real scalar value multiplied by an NxM unary matrix the first symbol of the first column; and

Selecting another symbol to be transmitted on the first to Mth antennas of the plurality of antennas at the second to the Mth time instants as the second to Mth columns of the multiplied NxM unary matrix transmitted on the first antenna at the first time instant symbol.

Advantageously, sending a plurality of introductory messages includes:

The tone for each L-1 channel sounding is transmitted at substantially equal energy levels.

Advantageously, generating a plurality of introductory messages includes:

Keying in at least one of the plurality of preamble information using the weighting factor matrix is used for antenna beam forming.

Advantageously, the method further comprises at least one of the following:

use known antenna beamforming coefficients for the weighting factor matrix; and

Antenna beamforming coefficients are transmitted on at least one preamble message to establish a matrix of weighting factors.

According to one aspect of the present invention, there is provided a method of generating a training symbol sequence for an RFIC of multiple output OFDM, the method comprising:

Generate M+1 OFDM symbols, where M is the number of RF outputs;

Select the symbol transmitted on the second to Mth antennas at the first instant as the first symbol of the first column of the MxM unary matrix multiplied by a real scalar value multiplied by the first antenna transmitted at the first instant ;

Select the symbols transmitted on the first to Mth antennas at the third to (M+1)th moments as the second to Mth columns of the same unary matrix multiplied by the symbols transmitted on the first antenna at the first moment a symbol; and

The symbols sent on the first to Mth antennas at the second moment are selected as the first symbols sent on the first to Mth antennas at the first moment.

Advantageously, each vector of M symbols transmitted at the first to (M+1)th time instants is multiplied by a diagonal matrix, each non-zero element of which is a different root.

Advantageously, the upper left cell of the diagonal matrix is 1.

Advantageously, the real scalar value multiplied by the unary matrix equals the discrete Fourier transform matrix.

Advantageously, if M=2, the real scalar values are multiplied by the unary matrix, so that the first row is equal to 1, -1, and the second row is equal to 11.

According to one aspect of the present invention, there is provided a method of generating a training sequence for an RF transceiver of multiple output OFDM, the method comprising:

Generate p*M OFDM symbols, where M is the number of RF outputs, and p is an integer greater than 1;

Select the symbol transmitted on the second to Mth antennas at the first instant as the first symbol of the first column of the MxM unary matrix multiplied by a real scalar value multiplied by the first antenna transmitted at the first instant ;

Selecting the symbols transmitted on the first to Mth antennas at the second to the Mth moments as the first symbols multiplied by the second to the Mth columns of the same unary matrix transmitted on the first antenna at the first moment; and

The symbols sent on each antenna at the (M+1)th to p*Mth moments are selected as (p-1) copies of the first M symbols sent on each of the M antennas.

According to one aspect of the present invention, there is provided a method for calculating the estimated NxM channel matrix in each J subcarrier for receiving OFDM transmission information, N is the antenna number expected to be transmitted, and M is the number of the receiving antenna, the method include:

Remove the first K samples in each block of I+K, I>=J samples;

apply a discrete Fourier transform on the remaining I samples of each block;

Select J subcarriers identified at the transmitter activated with non-zero symbols from each output block of I samples;

An NxM matrix is formed on each output on J subcarriers, each column of the matrix corresponds to the output from the Jth subcarrier at M consecutive time instants on the receiver antenna, and each row of the matrix corresponds to the output from all N receivers the jth subcarrier of the output on the antenna;

post-multiplying the matrix by the Hammett transpose used to multiply the MxM unary matrix of the symbols transmitted on the first transmit antenna; and

The complex conjugate of the first symbol obtained by transmitting on the first transmit antenna is multiplied by the resulting NxM matrix.

According to an aspect of the present invention, there is provided a radio frequency integrated circuit (RFIC) transmitter comprising:

a baseband processing module operatively connected to generate a plurality of preamble information; and

A radio frequency (RF) transmitter portion operably connected to transmit a plurality of preamble messages at a radio frequency via a plurality of antennas, wherein the baseband processing module generates a plurality of preamble messages comprising:

A carrier detect sequence at the transmission rate of the legacy version;

First channel sounding at the send rate of the legacy version;

signal field at the send rate of the legacy version; and

L-1 channel soundings at the MIMO transmission rate, where L corresponds to the number of channel soundings.

Advantageously, the MIMO transmission rate comprises the transmission rate of the legacy version.

Advantageously, the further function of the baseband processing module is to generate the signal domain by:

Indicates the frame length of MIMO wireless communications so that legacy wireless communications devices can be set to avoid collisions for the duration of MIMO wireless communications; and

Set reserved bits to indicate MIMO wireless communication.

Advantageously, the further function of the baseband processing module is to generate signal fields using reserved bits by:

Use the rate bits in the signal field to indicate the transmit antenna configuration and preamble information configuration.

Advantageously, the further function of the baseband processing module is to generate signal fields using reserved bits by:

The fictitious rate is specified in the rate bit and the length bit of the signal field, wherein the fictitious rate indicates the frame length of the MIMO wireless communication, the configuration of the transmitting antenna and the configuration of the preamble information.

Advantageously, the further function of the baseband processing module is to have the setting of reserved bits:

Use a default rate to specify the MIMO wireless communication frame length, transmit antenna configuration and preamble information configuration.

Advantageously, the sending rate of the legacy version includes:

A weighting factor is applied on each of the first channel sounding and signal fields.

Advantageously, the further functions of the baseband processing module include:

Selecting symbols to be transmitted on the first to Mth antennas of the plurality of antennas at the first time instant as a multiplied by a real scalar value multiplied by an NxM unary matrix the first symbol of the first column; and

Selecting another symbol to be transmitted on the first to Mth antennas of the plurality of antennas at the second to the Mth time instants as the second to Mth columns of the multiplied NxM unary matrix transmitted on the first antenna at the first time instant symbol.

Advantageously, the function of the RF transmitter portion is to send a plurality of preamble messages by:

The tone for each L-1 channel sounding is transmitted at substantially equal energy levels.

Advantageously, the further function of the baseband processing module is to generate a plurality of preamble information, including:

Keying in at least one of the plurality of preamble information using the weighting factor matrix is used for antenna beamforming.

Advantageously, applying the weighting factors comprises at least one of the following:

use known antenna beamforming coefficients for the weighting factor matrix; and

Antenna beamforming coefficients are transmitted on at least one preamble message to establish a matrix of weighting factors.

According to an aspect of the present invention, there is provided a method for generating a signal field in preamble information of wireless communication, the method comprising:

Indicates the frame length of MIMO wireless communication in the signal field, so that legacy wireless communication devices can be set to avoid collisions for the duration of MIMO wireless communication; and

Set reserved bits in the signal field to indicate MIMO wireless communication.

Advantageously, the method further comprises generating the signal fields using reserved bit settings by:

Use the rate bits in the signal field to indicate the configuration of the transmit antenna and the configuration of the preamble information.

Advantageously, the method further comprises generating the signal fields using reserved bit settings by:

The fictitious rate is specified in the rate bit and the length bit of the signal field, wherein the fictitious rate indicates the frame length of the MIMO wireless communication, the configuration of the transmitting antenna and the configuration of the preamble information.

Advantageously, the method further comprises, using reserved bit settings:

Use a default rate to specify the MIMO wireless communication frame length, transmit antenna configuration and preamble information configuration.

According to an aspect of the present invention, there is provided a radio frequency integrated circuit (RFIC) transmitter comprising:

a baseband processing module operatively connected to generate a plurality of preamble information; and

A radio frequency (RF) transmitter portion operably connected to transmit a plurality of preamble messages at a radio frequency via a plurality of antennas, wherein the baseband processing module generates a signal domain on each preamble message:

Indicates the frame length of MIMO wireless communication in the signal field, so that legacy wireless communication devices can be set to avoid collisions for the duration of MIMO wireless communication; and

Set reserved bits in the signal field to indicate MIMO wireless communication.

Advantageously, the further function of the baseband processing module is to generate signal fields using reserved bits by:

Use the rate bits in the signal field to indicate the configuration of the transmit antenna and the configuration of the preamble information.

Advantageously, the further function of the baseband processing module is to generate signal fields using reserved bits by:

Specify the fictitious rate in the rate bit and the length bit of the signal field, where the fictitious rate indicates the frame length of MIMO wireless communication, the configuration of the transmitting antenna and the configuration of the preamble information;

Advantageously, a further function of the baseband processing module is to use reserved bits:

Use a default rate to specify the MIMO wireless communication frame length, transmit antenna configuration and preamble information configuration.

Description of drawings

1 is a schematic block diagram of a wireless communication system according to the present invention;

2 is a schematic block diagram of a wireless communication device according to the present invention;

3 is a schematic block diagram of a wireless communication device according to the present invention;

4 is a schematic block diagram of a receiver portion of the wireless communication device of FIG. 2 according to the present invention;

FIG. 5 is a schematic block diagram of an embodiment of a baseband processing module of the wireless communication device in FIG. 3 according to the present invention;

Fig. 6 is a schematic block diagram of another embodiment of the baseband processing module of the wireless communication device shown in Fig. 3 according to the present invention;

Fig. 7 is a schematic block diagram of another embodiment of the baseband processing module of the wireless communication device in Fig. 3 according to the present invention;

FIG. 8 is a schematic block diagram of an embodiment of a baseband processing module of the wireless communication device shown in FIG. 2 according to the present invention;

9-11 are schematic diagrams of various frame formats that can be processed by the baseband processing module of FIG. 8;

Figure 12A is a schematic diagram of various frame formats that may be processed by the baseband processing modules of Figures 7 and 8;

Fig. 12B is a schematic diagram of a received signal model in the signal frame format of Fig. 12A;

Fig. 13 is a schematic diagram of preamble information sent on multiple antennas compatible with the baseband processing modules in Figs. 7 and 8;

Fig. 14 is a schematic diagram of the transmission model of the frame format in Fig. 12;

FIG. 15 is a schematic diagram of a frame format of the preamble information in FIG. 12A formed by a next-generation MIMO transmitter, especially a two-antenna next-generation MIMO transmitter;

FIG. 16 is a schematic diagram of a composition method of a frame format for forming the preamble information of FIG. 12A for a next-generation MIMO transmitter with three antennas;

FIG. 17 is a schematic diagram of a composition method of a frame format for forming the preamble information of FIG. 12A for a next-generation MIMO transmitter with four antennas;

Fig. 18 is a schematic block diagram of the manner in which legacy version devices and next generation devices interpret the inclusion of backward compatible frame headers.

Detailed ways

1 is a schematic block diagram illustrating a communication system 10 including a plurality of base stations and/or access points 12 and 16 , a plurality of wireless communication devices 18 - 32 , and network hardware components 34 . Wireless communication devices 18-32 may be laptop host computers 18 and 26, personal digital assistant hosts 20 and 30, personal computer hosts 24 and 32, and/or mobile telephones 22 and 28. At least part of the wireless communication device will be described in more detail with reference to FIG. 2 .

Base stations or access points 12 - 16 are operatively connected to network hardware 34 via local area network connections 36 , 38 , 40 . Network hardware 34 , which may be routers, switches, bridges, modems, system controllers, etc., provides WAN connection 42 for communication system 10 . Each base station or access point 12 and 16 has an associated antenna or antenna array for communicating with wireless communication devices within a jurisdiction, commonly referred to as a Basic Service Set (BSS) 11,13. Typically, a wireless communication device registers with a particular base station or access point 12 or 16 to obtain service from the communication system 10 .

Typically, base stations are used in mobile phone systems or similar systems, while access points are used in wireless networks built into homes or buildings. Regardless of the particular communication type, each wireless communication device includes a built-in radio or is connected to a radio. The radio includes a highly linear amplifier, and/or programmable multi-stage amplifiers as disclosed herein to improve performance, reduce cost, reduce size, and/or enhance broadband applications.

The wireless communication devices 22, 23, 24 are located in areas of the communication system 10 that are not connected to any access point. In this area, usually called Independent Basic Service Set (IBBS) 15, wireless communication devices generate a real (ad-hoc) network direct communication (such as point-to-point or point-to-multipoint) through allocated channels.

FIG. 2 is a schematic block diagram of a wireless communication device including a host device 18 - 32 and an associated radio or base station 60 . For the mobile phone host, the radio transceiver 60 is a built-in component. For PDA hosts, laptop hosts and/or personal computer hosts, the radio 60 may be built-in or an externally connected component. In this embodiment, the base station may comply with multiple wireless local area network (WLAN) protocols, including but not limited to, such as IEEE 802.11n. The device in Figure 2 is a Multiple Input Multiple Output (MIMO) device. The IEEE 802.11n device mentioned here refers to the next-generation WLAN device; the IEEE 802.11a/b/g device mentioned at the same time is a multiple-input single-output (MISO) device, which is called a legacy version device. However, the MISO device, which will be described in detail with reference to FIG. 3 , must work with the MIMO device in FIG. 2 .

As shown, host device 18 - 32 includes processing module 50 , memory 52 , radio interface 54 , input interface 58 and output interface 56 . The processing module 50 and the memory 52 execute instructions related to the daily operation of the host device. For example, for a mobile phone host device, the processing module 50 performs corresponding communication functions according to specific mobile phone standards.

The radio interface 54 allows data to be received and transmitted from the radio 60 . For data received from radio 60 (eg, incoming data), radio interface 54 provides the data to processing module 50 for further processing and/or routing to output interface 56 . The output interface 56 provides a connection to an output display device such as a display, monitor, speaker, etc., so that the received data can be displayed. The radio interface 54 also provides data from the processing module 50 to the radio 60 . The processing module 50 may receive output data from input devices such as a keyboard, numeric keypad, microphone, etc. through the input interface 58 or generate data itself. For data received via the input interface 58 , the processing module 50 may perform corresponding host functions on the data and/or route the data to the radio 60 via the radio interface 54 .

Radio transceiver or base station 60, including a host interface 62, baseband processing module 64, memory 66, multiple radio frequency (RF) transmitters 68-72, receive/transmit (T/R) module 74, multiple antennas 82-86 , a plurality of RF receivers 76-80 and a local oscillator module 100. The baseband processing module 64 performs the digital receiver function and the digital transmitter function respectively in conjunction with the operating instructions stored in the memory 66 . Digital receiver functions include, but are not limited to, digital IF to baseband conversion, demodulation, constellation demapping, decoding, deinterleaving, fast Fourier transform, cyclic prefix removal, space-time decoding, and/or anti-irregular transformation. Digital transmitter functions include, but are not limited to, randomization, coding, interleaving, constellation mapping, modulation, inverse fast Fourier transform, cyclic prefix addition, space-time coding, and/or digital baseband to IF conversion. Baseband processing module 64 may be implemented using one or more processing devices. These processing devices can be microprocessors, microcontrollers, digital signal processors, microcomputers, central processing units, field programmable gate arrays, programmable logic devices, state machines, logic circuits, analog circuits, digital circuits, and/or Or any signal (analog and/or digital) processing device based on operating instructions. Memory 66 may be a single memory device or multiple memory devices. The memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, and/or a device capable of storing digital information. It is noted that when the processing module 64 realizes one or more of its functions through state machines, analog circuits, digital circuits and or logic circuits, the memory for storing corresponding operation instructions is also embedded in the state machine, analog circuits, digital circuits and/or logic circuits. or logic circuits in circuits.

In operation, the radio 60 receives output data 88 from a host device via the host interface 62 . Baseband processing module 64 receives output data 88 and, based on mode select signal 102 , generates one or more output symbol streams 90 . Mode select signal 102 indicates a particular mode in a mode select table, described in Mode Select Table at the end of this detailed discussion. For example, the mode selection signal 102 may indicate that the frequency band is 2.4GHz, the channel bandwidth is 20 or 22MHz, and the maximum bit rate is 54Mb/s or greater, such as 122MBPS. In this general type, the mode select signal will further specify a specific rate. In addition, the mode selection signal may indicate a specific modulation mode, including but not limited to Barker coded modulation, BPSK, QPSK, CCK, 16QAM and/or 64QAM.

The baseband processing module 64 generates one or more output symbol streams 90 from the output data 88 according to the mode selection signal 102 . For example, the baseband processing module 64 generates an output symbol stream 90 if the mode selection signal 102 indicates that only a single transmit antenna is used in the selected mode. Alternatively, if the mode select signal indicates 2, 3 or 4 antennas, the baseband processing module 64 will generate 2, 3 or 4 output symbol streams 90 from the output data 88 corresponding to the number of antennas.

Depending on the number of output streams 90 produced by baseband processing module 64 , a corresponding number of RF transmitters 68 - 72 can convert output symbol streams 90 into output RF signals 92 . The transmit/receive module 74 outputs an RF signal 92 and provides each transmit signal to a corresponding antenna 82-86.

When the radio 60 is in a receive mode, the transmit/receive module 74 receives one or more incoming RF signals via the antennas 82-86. T/R module 74 provides incoming RF signal 94 to one or more RF receivers 76-80. The RF receivers 76-80, explained in more detail with reference to FIG. 4, convert the incoming RF signal 94 into a corresponding number of incoming symbol streams 96. The incoming symbol stream 96 will correspond to a particular pattern of received data. The baseband processing module 60 receives the incoming symbol stream 90 and converts it into incoming data 98, which is provided to the host device 18-32 via the host interface 62. For further discussion of the implementation of the radio transceiver or base station 60, see co-pending patent application, Attorney No. BP3516, entitled "WLAN TRANSMITTER HAVING HIGH DATATHROUGHPUT" Co-pending patent application dated 2/19/04 and "WLAN RECEIVERHAVING AN ITERAGTIVE DECODER," Attorney No. BP3529, provisional filing date 2/19/04.

Those of ordinary skill in the technical field may know that the wireless communication device in FIG. 2 may be implemented using one or more integrated circuits. For example, the host device can be implemented with one integrated circuit, the baseband processing module 64 and memory 66 can be implemented with a second integrated circuit, and the remaining components of the wireless transceiver 60, except antennas 82-86, can be implemented with a third integrated circuit. As an alternative example, radio 60 may be implemented on an integrated circuit. In another example, the processing module 50 and the baseband processing module 64 on the host may be a common processing device implemented by a single integrated circuit. Further, the memory 52 and the memory 66 may also be implemented on an integrated circuit, and/or integrated on a common processing module of the processing module 50 and the baseband processing module 64 .

FIG. 3 is a block diagram showing a wireless communication system including host devices 18-32 and associated radios 61. As shown in FIG. For the mobile phone host, the wireless receiving device 61 is a built-in component. For PDA hosts, laptop hosts, and/or personal computer hosts, the wireless transceiver 61 may be a built-in or externally connected component. Host devices 18-32 operate as discussed with reference to FIG. 1 . The WLAN device of Figure 3 will operate in compliance with one or more of the standards in IEEE 802.11a/b/g. Different from the MIMO device shown in FIG. 2, the device shown in FIG. 3 is a MISO device.

The wireless transceiver 61 includes a host interface 52, a baseband processing module 64, an analog-to-digital converter 111, a filter module 109, an IF hybrid down-conversion stage 107, a receiver filter 101, a low-noise amplifier 103, a transmitter/receiver Switch 73, Local Oscillator Block 74, Memory 66, Digital Transmitter Processing Block 76, Digital to Analog Converter 78, Filter Block 79, IF Hybrid Upconversion Stage 81, Power Amplifier 83, Transmitter Filter Block 85 and Antenna 86. The antenna 86 may be a single antenna shared by the transmit and receive paths by adjusting the Tx/Rx switch 73, or include separate antennas for the transmit and receive paths. The implementation of the antenna will depend on the communication specific standard that the wireless communication device complies with. The functions of the baseband processing module 64 are the same as above, and one or more functions performed will be described in FIGS. 5-19 .

In operation, wireless transceiver device 61 receives output data 88 from a host device via host interface 62 . Host interface 62 routes output data 88 to baseband processing module 64, which processes output data 88 according to a particular wireless communication standard (e.g., IEEE 802.11a/b/g, Bluetooth, etc.) to generate output time-domain baseband (BB )Signal.

A digital-to-analog converter 77 converts the output time-domain baseband signal from the digital domain to the analog domain. The filter module 79 filters the analog signal before providing it to the IF upconversion module 81. The IF upconversion module converts the analog baseband or low IF signal to RF signal based on the transmitter local oscillator 83 provided by the local oscillator module 100 . Power amplifier 83 amplifies the RF signal to produce output RF signal 92 , which is filtered by transmitter filter module 85 . Antenna 86 transmits output RF signal 92 to a target device such as a base station, access point and/or other wireless communication device.

The wireless transceiver device 61 also receives, via the antenna 86, an access RF signal 94 transmitted by a base station, access point, or other wireless communication device. The antenna 86 provides the incoming RF signal 94 to the receiver filter module 101 through the Tx/Rx switch 73 . The Rx filter 71 bandpass filters the incoming RF signal 94 and provides the filtered RF signal to the low noise amplifier 103 to amplify the RF signal 94 to generate an amplified incoming RF signal. The low noise amplifier 72 provides the amplified access RF signal to the IF down-converter module 107, and directly converts the amplified access signal into an inserted low IF signal or baseband according to the receiver local oscillator 81 provided by the local oscillator module 100 Signal. The down conversion block 70 provides the incoming low IF signal or baseband signal to the filter/gain block 68 . The filtering module 109 filters the incoming low IF signal or the incoming baseband signal to generate a filtered incoming signal.

An analog-to-digital converter 111 converts the filtered incoming signal into an incoming time-domain baseband signal. The baseband processing module 64 decodes, scrambles, demaps, and/or demodulates the incoming time-domain baseband signal into retrieved incoming data 98 conforming to the particular wireless communication standard implemented by the wireless transceiver 61 . The host interface 62 provides the retrieved access data to the host device 18-32 via the radio interface 54.

Those of ordinary skill in the technical field may know that the wireless communication device shown in FIG. 3 may be implemented using one or more integrated circuits. For example, the host device can be implemented with one integrated circuit, the baseband processing module 64 and memory 66 can be implemented with a second integrated circuit, and the remaining components of the wireless transceiver 61 except the antenna 86 can be implemented with a third integrated circuit. As an alternative example, the radio transceiver 61 may be implemented using an integrated circuit. In another example, the processing module 50 and the baseband processing module 64 of the host device may be general processing devices, which can be realized by using an integrated circuit. Further, the memory 52 and the memory 6 may be implemented on one integrated circuit, and/or implemented on the same integrated circuit of the common processing module of the processing module 50 and the baseband processing module 64 .

FIG. 4 is a schematic block diagram of each RF receiver 76-80. In this embodiment, each RF receiver 76-80 includes an RF filter 101, a low noise amplifier (LNA) 103, a programmable gain amplifier (PGA) 105, a down conversion module 107, an analog filter 109, Analog-to-digital conversion module 111 and digital filter and down-sampling module 113 . RF filter 101, which may be a high frequency bandpass filter, receives incoming RF 94 signal 94 and filters it to generate a filtered incoming RF signal. The low noise amplifier 103 amplifies the filtered incoming RF signal 94 based on the set gain and provides the amplified signal to the programmable gain amplifier 105 . The programmable gain amplifier further amplifies the incoming RF signal before providing the signal to the down conversion module 107 .

The down-conversion block 107 includes a pair of mixers, a summation block and a filter to mix the incoming RF signal with a local oscillator (LO) provided by the local oscillator block to generate an analog baseband signal. The analog filter 109 filters the analog baseband signal, provides this to the analog-to-digital conversion module 111, and converts it into a digital signal. The digital filter and downsampling module 113 filters the digital signal and then adjusts the sampling rate to generate the access symbol stream 96 .

FIG. 5 is a functional schematic block diagram of the implementation of the baseband processing module 64 in FIG. 3 . In this embodiment, the implementation of the baseband processing module 64 includes a guard interval clearing module 130 , a fast Fourier transform module 132 , a demapping/segmentation module 134 , a deinterleaving processing module 136 , a decoding module 138 , and a channel estimation module 120 . In this embodiment, the channel estimation module 120 includes an encoding module 140 , an interleaving processing module 142 , a mapping module 144 , a channel estimation module 146 and a channel estimation updating module 148 . It is further shown that a frame 155 following IEEE 802.11a and/or IEEE802.11g includes a short training sequence (STS) 157, two long training sequences (LTS) 159, 161, a signal field (SIG) 163 and A plurality of data payload areas 165-169.

Baseband processing module 64 processes portions of frame 155 sequentially. As is well known, the baseband processing module 64 processes the short training sequence 157 to identify the presence of the frame, to initially determine whether the frame 155 is valid, and to establish initial gain settings (e.g., LNA gain, programmable gain amplifier gain, analog - digital gain, etc.).

The baseband processing module 64 then processes the long training sequences 159 and 161 to further establish the validity of the frame 155 and removes the guard intervals between the long training sequences 159 and 161 by the guard interval (GI) cleanup module 130 . The fast Fourier transform module 132 converts the time domain signal represented by the long training sequence into a plurality of time domain tones 150 . Demapping/segmentation module 134 demaps multiple frequency domain tones 150 to generate demapped tones 152 . The interleaving module 136 deinterleaves the demapped keynote 152 to generate deinterleaved data 154 . Decoding module 138 decodes deinterleaved data 154 to generate accessed decoded data 98 .

For example, if the baseband processing module 64 is configured to comply with IEEE 802.11a and/or 802.11g, the incoming time-domain baseband signal is an Orthogonal Frequency Division Multiplex (OFDM) modulated signal in the 5GHz band and/or the 2.4GHz band. The FFT module 132 converts the time domain signal into a plurality of frequency domain tones. Each frequency domain tone represents a subcarrier of the channel. As is well known, in the 802.11a and/or 802.11g standards, there are 48 data subcarrier signals and 4 pilot subcarrier signals, a total of 52 non-zero subcarrier signals in one channel. The remaining 12 subcarrier signals in the channel are all zero to provide at least a portion of the guard interval. Each tone represents modulated data conforming to PBSK, QPSK, 16 QAM and/or 64 QAM. The demapping determines the specific symbol vectors corresponding to the corresponding key, which will then be deinterleaved by the deinterlacing processing module 136 . Decoding module 138, which may be a VITERBI decoder, receives symbol vectors representing modulated data and decodes them based on retrieved bit data represented by constellation mapped symbols.

The channel estimation module 120 basically replicates the baseband transmit function to generate a remapped frequency domain tone from the decoded data generated by the decoding module 138 . As shown, encoding module 140 , which may be a rate 1/2 convolutional encoder, encodes incoming decoded data bits 98 into re-encoded data 156 . The encoding module 140 is basically the reverse operation of the decoding module 138, performing the same encoding function as the encoding sent to a specific receiver by the wireless communication device in the transmitting operation.

The interleaving module 142 interleaves the re-encoded data 156 to generate re-interleaved data 158 . The mapping module 144 maps the re-interleaved data 158 into a plurality of re-mapped frequency-domain tones 160 . These functions are inverse to those performed by demap/segmentation module 134 and deinterlace processing module 136 .

The channel estimation module 146 uses the plurality of remapped frequency domain tones 160 and the plurality of frequency domain tones 150 to generate a channel estimate 162 for processing a particular portion of the frame 155 . Accordingly, channel estimate 162 may generate a yielding LTS channel estimate 171 for long training sequences 159 and 161 . Furthermore, channel estimation may be performed on the signal field 163 indicating the information portion of the frame to generate a service field channel estimate 173 . Still further, the channel assessment can be performed on a number of data payload fields 165-169 to generate a data channel assessment.

Channel estimate update module 148 receives channel estimate 162 for a particular portion of frame 155 and updates the previous channel estimate to produce an updated channel estimate 163 . Those of ordinary skill in the art may know that the LTS channel estimation 171 comes from the existing channel estimation of a wireless WLAN receiver conforming to 802.11a and/or 802.11g.

Referring to frame 155, channel estimation module 120 generates an initial channel estimate for that frame based on LTS channel estimation 171 . Upon receiving the service or signal field 163, the channel estimation module 120 generates a service field channel estimate 173 for the service field. The signal assessment module 120 then updates the channel estimate 163 based on the initial channel estimate and the newly determined service domain channel estimate 173 . When the first data field payload is received, the channel assessment module 120 generates a corresponding channel estimate for the data payload. The previously updated channel estimate is then updated with the first loaded channel estimate. The channel assessment module 120 will determine a corresponding channel assessment for each received data payload, and update the current channel assessment 163 accordingly. Alternatively, channel estimation module 120 may use only one set of data payload portions to determine updates to channel estimation 163 . Which fraction of the data payload is used can be determined in advance (e.g. use every 4th data payload) or more depending on the power of the associated data payload, where the energy level needs to exceed a limit to update the channel Evaluate.

As an example of the operation of the channel estimation module 146 and the channel estimation update module 148, the received FFT is output on the Kth tone as:

Y _k ＝Z _k H _k +V _k

Dropping the subscript k for any key, the equation can be rewritten as:

Y＝ZH+V≈CN(0, σ ² )

Here, Y denotes the information part and/or payload part of the received frame, H denotes the corresponding channel estimate, V denotes the noise part of the information part and/or payload part of the received frame, and Z denotes the received Multiple demapping frequency domain tone of the information part and/or payload part of the frame, where Z can be expressed as Z=K _MOD X, therefore:

Y=(Z _i +jZq)(Hi+jHq)+(Vi+jVq)

=(Z _i Hi-ZqHq)+j(ZqHi+ZiHq)+(Vi+jVq) Therefore:

Yi=ZiHi-ZqHq+Vi

Yq=ZqHi+ZiHq+Vq so

ZiYi+ZqVq=(Zi ² +Zq ² )Hi+ZiVi+ZqVq, so the channel estimation can be expressed as:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; DNi</span>}}<span\; class="notranslate">\; =</span>{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="wxya\; Z\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">wxya</figure-callout></span><figure-callout\; id="2"\; label="wxya\; Z\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}{{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{}}^{}}$

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="wxya\; Z\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">wxya</figure-callout></span><figure-callout\; id="2"\; label="wxya\; Z\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}{{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{}}^{}}$

$<span\; class="notranslate">\; =</span>\frac{{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="Z\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">Z</figure-callout></span><figure-callout\; id="2"\; label="Z\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="Z\; q"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">Z</figure-callout></span><figure-callout\; id="2"\; label="Z\; q"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="Z\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">Z</figure-callout></span><figure-callout\; id="2"\; label="Z\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

$<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="Z\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">Z</figure-callout></span><figure-callout\; id="2"\; label="Z\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

$<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; MOD</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="x\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">x</figure-callout></span><figure-callout\; id="2"\; label="x\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}$

As a further example, high-energy constellation points can be used to reduce evaluation noise. For example, consider 64QAM, where $K_{\mathrm{mod}}=\frac{1}{42}$

$\frac{{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; MOD</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="x\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">x</figure-callout></span><figure-callout\; id="2"\; label="x\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 42</span>}{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="x\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">x</figure-callout></span><figure-callout\; id="2"\; label="x\; i"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}$

In this example, channel estimation updates are only performed if the constellation energy is greater than 42. Under this premise, the following constellation coordinates can provide the following energy levels:

(X _i ，X _q ) X _i ² +X _q ²

I1, I7 50

I3, I7 58

I5, I7 74

i7, i7 98

i5, i5 50

FIG. 6 is another alternative implementation of the baseband processing module 64 . In this embodiment, the baseband processing module 64 includes a guard interval removal module 130 , an FFT module 132 , a demapping/segmentation module 134 , a deinterleaving processing module 136 , a decoding module 138 and a channel estimation module 120 . In this embodiment, the channel estimation module 120 includes an interleaving processing module 142 , a mapping module 144 , a channel estimation module 146 and a channel estimation updating module 148 . For the functions of the modules 130-138, refer to the description corresponding to FIG. 5, and convert the received time-domain baseband signal into the received decoded data 98.

In this embodiment, the channel assessment module 120 receives the deinterleaved data 154 from the module 136 through the interleaving module 142 . The interleaving module 142 re-interleaves the data to generate re-interleaved data 158 . The mapping module 144 maps the re-interleaved data 158 into a plurality of demapped frequency-domain tones 160 . The channel estimate module 146 and the channel estimate update module 148 function as described in FIG. 5 to generate an updated channel estimate 163 .

FIG. 7 is a schematic block diagram of another embodiment of the baseband processing module 64 . In this embodiment, the baseband processing module 64 is configured to include a guard interval removal module 130 , an FFT module 132 , a demapping/segmentation module 134 , a deinterleaving processing module 136 , a decoding module 138 and a channel estimation module 120 . In this embodiment, the channel estimation module 120 includes a mapping module 144 , a channel estimation module 146 and a channel estimation updating module 148 . Modules 130 - 138 operate as correspondingly described in FIG. 5 to convert the incoming time-domain baseband signal into incoming decoded data 98 .

In this embodiment, the channel assessment module 120 receives the demapped tone 152 through the mapping module 144 . The mapping module 144 maps the keynote 152 into an OFDM modulated keynote to generate a plurality of remapped frequency domain keynotes 160 . The channel estimate module 146 and the channel estimate update module 148 function as described in FIG. 5 to generate an updated channel estimate 163 .

FIG. 8 shows the baseband processing of the receiver of the wireless communication device according to FIG. 2 . Baseband processing includes space/time decoder 294, multiple Fast Fourier Transform (FFT)/cyclic prefix removal modules 296-300, multiple symbol demapping modules 302-306, multiplexer 308, deinterleaver 310 , a channel decoder 312 , an anti-irregular transformation module 314 and a channel estimation module 120 . The baseband processing module may further include a mode management module 175 to generate a setting 315 and a rate selection 311 from an operating mode selection input 313 . The space/time decoding module 294 receives P inputs 319 from the receiver path and generates M outputs 317 . In this embodiment, the space/time decoding module 294 multiplies the input symbols on each path with a decoding matrix of the following form:

$\left[\begin{array}{ccccc}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\\ <span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="C"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">C</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="*\; C"\; filenames="C20051006740700351.png,C20051006740700431.png"\; state="\{\{state\}\}">*</figure-callout></span><figure-callout\; id="1"\; label="*\; C"\; filenames="C20051006740700351.png,C20051006740700431.png"\; state="\{\{state\}\}">\; </figure-callout>}& {\mathrm{<span\; class="notranslate">\; </span>}}_{}^{}{\mathrm{<span\; class="notranslate">C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; *</span>}& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; m</span>}}\end{array}\right]$

Note that the rows of the decoding matrix correspond to the number of input paths, and the columns correspond to the number of output paths. Note that the number of M output paths 317 for spatial and temporal decoding may be equal to the number of P input 318 paths for spatial and temporal decoding or the input path P may be equal to M+1.

The FFT/cyclic prefix removal modules 296-300 convert M symbol streams from the time domain into frequency domain symbols to generate M frequency domain symbol streams. In one embodiment, the prefix removal function removes interfering interaction symbols based on a specific prefix. Note that, in general, a 64-point FFT can be used for a 20MHz channel, while a 128-point FFT can be used for a 40MHz channel.

Symbol demapping modules 302-306 convert frequency domain symbols into bitstream data. In one embodiment, each symbol demapping module maps quadrature amplification modulated QAM symbols (such as BPSK, QPSK, 16QAM, 64 QAM, 256 QAM, etc.) into bit stream data. Note that for backward compatibility with IEEE 802.11(a), double gray coding can be used. A multiplexer 308 combines the demapped symbol streams into a single path. The deinterleave processor 310 deinterleaves the single path.

Deinterleaved data is decoded by iterative decoder 312, which can be found in co-pending patent application entitled "WLAN RECEIVERHAVING AN ITERATIVE DECODER," Attorney It is described in more detail in BP3529, provisional application dated 2/20/04. The anti-irregularity transformer 314 inversely transforms the data to generate the access data 98 . In one embodiment, anti-ragged transformer 314 removes (in GF2) the pseudo random sequence from the decoded data. The pseudo-random sequence can be generated by the feedback of a shift register with a generator having the polynomial S(x)=x ⁷ +x ⁴ +1 to produce irregular data.

The channel estimation module 120 may be connected to the output of the deinterleaving processing module 310 to receive the deinterleaving processed data, or connected to the output of the channel decoder 312 to receive the decoded data. If the channel estimation module 120 is connected to receive decoded data, its function is the same as that described above with reference to FIG. 5 . If the channel estimation module 120 receives deinterleaved data, its function is consistent with that described above with reference to FIG. 6 .

FIG. 9 shows a frame 200 constructed according to IEEE 802.11n if and only if an 802.11n compliant device is within the closest range for wireless communication. As shown, frame 200 includes a short training sequence (STS) 517, a plurality of supplemental long training sequences (suppl LTS) 201-203, and a plurality of data payload portions 205-207. For this type of frame, the channel estimation module 120 of FIG. 8 will generate an initial channel estimate based on the LTS channel estimate, as described with reference to FIG. 5 . Channel estimation module 120 then updates the channel estimate for each channel estimate that is generated for the data payload portion. As shown, the first data payload has a corresponding channel estimate used to update the LTS channel estimate, resulting in an updated channel estimate. The next data payload also generates a corresponding channel estimate which is used to update the previously updated channel estimate.

FIG. 10 shows a frame 202 conforming to the IEEE 802.11n standard, where the communication domain includes 802.11n, 802.11a and/or 802.11g devices. In this example, frame 202 includes Short Training Sequence (STS) 157, Long Training Sequence (LTS) 159 and 161 according to 802.11a and/or 802.11g standards, Service Field (SIG ) 163, supplementary long training sequence (suppl LTS) 201-203, high data service domain 211 and multiple data payload portions 205-209. The frame 202 shown in the figure includes two frame information fields: service field 163 and high data service field 211 .

The channel estimation module 120 in FIG. 8 generates a channel estimation through the first determined LTS channel estimation, and then updates the channel estimation according to the channel estimation of the corresponding service domain. The channel estimate module then determines the channel estimate used to supplement the long training sequence, and the channel estimate used to update the previous update. An update of the channel estimate is then performed for the high data service domain 211 and one or more data payload portions 205-209.

FIG. 11 shows another IEEE 802.11n compliant frame 204 for communications involving 802.11n devices, 802.11a devices, 802.11b devices, and/or 802.11g devices. In this example, frame 204 includes short training sequence (STS) 157, legacy version long training sequence 1 and 2 (LTS) 159 and 161, legacy version serving field (SIG) 163, MAC partitioning field (partitioning field) 213, Supplementary Long Training Sequence (suppl LTS) 201-203, High Data Service Domain 211 and Multiple Data Payload Sections 205-209. The channel estimation module 120 of FIG. 8 determines the initial channel estimation by utilizing the LTS channel estimation. Channel estimation module 120 then determines a channel estimate for each field and/or portion of frame 204 and uses the channel estimate to update previous channel estimates. In this example, the frame 204 includes the legacy service field 163, the MAC separation field 213, and the high data service field 211 as the information part of the frame.

FIG. 12A is a schematic diagram of a portion of a frame 221 that may be processed by the baseband processing module of FIGS. 7 and 8 . Frame 221 includes short training sequence (STS) 157 , guard interval (GI) 223 , two channel soundings (CS) 245 and 247 , and signal field (SIG) 163 . In one embodiment, the duration of frame 221 is 20 microseconds (μS), where STS takes 4 Ms, GI takes 1.6 μS, each CS takes 3.2 μS, and the signal domain takes 4 μS. In STS, each symbol consumes 0.8μS.

STS 157 includes 10 short training symbols (S1-S10) 225-243. Channel sounding 245 and 247 of frame 221 (for example, long training in IEEE 802.11a) meets the following two criteria:

The legacy version (802.11a/g) base station can use and decode the signal field, obtain the frame length, and set the clear channel assessment (CCA) indication;

Next-generation 802.11n base stations can be used for (partial) MIMO channel estimation.

Satisfying the above criteria, the channel estimation error can be reduced at a given amount of overhead and the sequence will be more energy efficient. Without changing the signal domain decoded at the legacy base station, the existing long training and linear weights of the signal symbols are used at the transmitter antenna input, where the same weights are used in the first two long training symbols and the legacy signal domain, with Decoded by legacy base stations.

FIG. 12B is a schematic diagram of a received signal model in the signal frame format of FIG. 12A . As shown, received signal (X _k ) 255 includes transmitted channel detection signal (S _k ) 253 , channel estimate (H _k ) 251 and noise matrix (N _k ) 257 . Actually, the received signal X _k =S _k *H _k +N _k , where S _k , H _k and N _k are all matrices. In this embodiment, both the channel estimation H _k 251 and the sent channel sounding signal S _k can be expressed in the following form:

X _k ＝ S _k H _k +N _k

According to this signal model, the zero-forcing (ZF) MIMO channel estimate can be calculated as:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}$

If the long training sequence has been defined, S _k becomes a unary matrix of real scalar order. In this case, the minimum mean-square (MMSE) channel estimate can be calculated as:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; \&eta;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}$

$\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; \&eta;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

Here, for simplicity, nk is assumed to be an independently identically distributed (i.i.d) Gaussian (individually identically distributed Gaussian), and is chosen as a "good long training option". Note that due to the deliberate choice of S, there is no reason to perform an MMSE estimate of zero forcing (ZF) on the sequence.

FIG. 13 is a schematic diagram of preamble information 261-265 transmitted on multiple antennas (TX1 to TXM) compatible with the baseband processing modules of FIGS. 7 and 8 . In one embodiment, each preamble message 261-265 includes a carrier detect (CD) field 267, 277, 287, a first channel sounding (CS M, 1) 269, 279, and 289, a signal field (SIG) 271, 281, 291 and L-1 remaining channel soundings (CSM, L). In this embodiment, the channel detection CD 267, 277, 287, the first channel detection 269, 279, 289, and the signal fields 271, 281, 291 may correspond to legacy version wireless protocols (such as IEEE802.11a, b, and / or short training sequence, long training sequence and signal field in g).

According to the teachings of the present invention, the preamble energy will be sent by IEEE 802.11n STA or AP on all or nearly all antennas using all or nearly all tones for all L sounding sequences. When L=M, the energy of L probes transmitted from each of the M antennas is 2s2/M. The total energy of matrix channel estimation when L=M is 2Ms ² . Thus, the energy delivered is M times greater than when a single tone is delivered at any one time.

FIG. 14 is a schematic diagram of the transmission model of the frame format in FIG. 12 . For this transmission format, in order to meet the purpose of backward compatibility and meet the requirements of next-generation channel assessment, an appropriate W is selected to ensure that W or W-1 is relatively simple to implement. Furthermore, antenna beamforming via [w11...wlM] from MIMO transmitters (next generation devices) can be well received by legacy 802.11a/g devices.

In this embodiment, the channel sounding (S _K ) 253 is multiplied by a number of weighting factors (W _k,m ) 68-72, where k corresponds to the number of channel soundings ranging from 1 to 1 and m corresponds to the transmit antenna 82-86 numbers. The weighted channel sounding signals are converted to RF signals via transmitters 68-72 and then transmitted via antennas 82-86. In this embodiment, the weighting factor matrix can be as follows:

Null signals can be formed from transmissions that take place all the time on all antennas at all times. Compensating the null signal acts as a wave shaper by selecting a sequence of weights so that the null signal remains in a specific direction. For example, for the case of vector w1 = [11] (a row in the above W matrix for the 2 TX case), the null signal will remain at -90 degrees and +90 degrees. Therefore, it is not very favorable in certain directions compared to the signal input receivers of other legacy WLAN devices.

According to the present invention, different combining weights can be applied to each subcarrier on the M-1 transmit antennas. This results in a different transmission scheme on each subcarrier, which results in less energy and capacity loss in the worst direction.

FIG. 15 is a schematic diagram of a frame format of the preamble information in FIG. 12A formed by a next-generation MIMO transmitter, especially a two-antenna next-generation MIMO transmitter. In the illustration, two preamble messages are generated, one for each active antenna. The first preamble message 311 sent through the first antenna includes a double guard interval (GI2) 313, the first channel sounding (CS0, 0) 315, the second channel sounding (CS0, 1) 317, the guard interval (GI) 319 , signal field (SIG) 321 , another guard interval (GI) 323 and a third channel sounding (CS0,2) 325 . The second preamble message 327 sent through the second antenna includes a double guard interval (GI2) 329, the first channel sounding (CS1, 0) 331, the second channel sounding (CS1, 1) 333, the guard interval (GI) 335, signal field (SIG) 337, another guard interval (GI) 339 and a third channel sounding (CS1,2) 341.

In this embodiment, different channel detection adopts the following methods:

s ₀₁ =s ₀₀

${\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="10"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}$

s ₁₁ =s ₁₀

s ₀₂ =s ₀₀

${\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="12"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}$

For the channel sounding above, the following weighting factors will be used:

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="10"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="11"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="20"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 20</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; one</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\left[\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]<span\; class="notranslate">\; \&CenterDot;</span>\left[\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}\end{array}\right]$

$<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& <span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}\\ {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}\end{array}\right]$

The first numerical subscript of the channel detection corresponds to the number of the antenna, and the second numerical subscript corresponds to the serial number of the symbol. K corresponds to the number of channel detection. For example, S _{10, K} corresponds to the first symbol sent by the first antenna for sounding the kth channel.

To obtain a different transmission method for each subcarrier, use the following method:

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="N\; subcarriers"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">N</figure-callout></span><figure-callout\; id="2"\; label="N\; subcarriers"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="N\; subcarriers"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">N</figure-callout></span><figure-callout\; id="2"\; label="N\; subcarriers"\; filenames="C20051006740700432.png,C20051006740700481.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}$

FIG. 16 is a schematic diagram of a frame format for forming the preamble information of FIG. 12A for a three-antenna next-generation MIMO transmitter. As shown in the figure, three preamble messages are generated, one for each activated antenna. The first preamble message 351 sent through the first antenna includes a double guard interval (GI2) 353, the first channel sounding (CS0, 0) 355, the second channel sounding (CS0, 1) 357, the guard interval (GI) 359, signal field (SIG) 361, another guard interval (GI) 363, third channel sounding (CS0, 2) 365, third guard interval (GI) 367 and fourth channel sounding (CS0 , 3) 369. The second preamble message 371 sent through the second antenna includes a double guard interval (GI2) 373, the first channel sounding (CS1, 0) 375, the second channel sounding (CS1, 1) 377, the guard interval (GI) 379, signal domain (SIG) 381, another guard interval (GI) 383, third channel sounding (CS1, 2) 385, third guard interval (GI) 387 and fourth channel sounding (CS1 , 3) 389. The third preamble message 391 transmitted through the third antenna includes a double guard interval (GI2) 393, the first channel sounding (CS2, 0) 395, the second channel sounding (CS2, 1) 397, the guard interval (GI) 399, signal domain (SIG) 401, another guard interval (GI) 403, third channel sounding (CS2, 2) 405, third guard interval (GI) 407 and fourth channel sounding (CS2 , 3) 409.

For different channel detection, the following weight factor matrix can be used:

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\left[\begin{array}{ccc}{\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="10"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="11"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="12"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="20"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 20</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; one</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; two</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="30"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 30</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 31</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="32"\; label="s"\; filenames="C20051006740700351.png"\; state="\{\{state\}\}">s</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 32</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{ccc}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}\\ {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span>}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span>}& {\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span>}\end{array}\right]$

To obtain a different delivery scheme for each subcarrier, use the following:

_θk = π·k/6

φ _k = π·(k+4)/6

FIG. 17 is a schematic diagram of a frame format for forming the preamble information of FIG. 12A for a four-antenna next-generation MIMO transmitter. As shown in the figure, four preamble messages are generated, one for each activated antenna. The first preamble message 411 is sent through the first antenna, including a double guard interval (GI2) 413, the first channel sounding (CS0, 0) 415, the second channel sounding (CS0, 1) 417, the guard interval ( GI) 419, signal domain (SIG) 421, another guard interval (GI) 423, third channel sounding (CS0, 2) 425, third guard interval (GI) 427, fourth channel sounding (CS0, 3) 429, guard interval (GI) 431 and fifth channel sounding (CS0,4) 435. The second preamble message 441 is transmitted through the second antenna, including a double guard interval (GI2) 443, the first channel sounding (CS1, 0) 445, the second channel sounding (CS1, 1) 447, the guard interval ( GI) 449, signal field (SIG) 451, another guard interval (GI) 453, third channel sounding (CS1, 2) 455, third guard interval (GI) 457, fourth channel sounding (CS1, 3) 459, guard interval (GI) 461 and fifth channel sounding (CS1,4) 465. The third preamble message 471 is sent through the third antenna, including a double guard interval (GI2) 473, the first channel sounding (CS2, 0) 475, the second channel sounding (CS2, 1) 477, the guard interval ( GI) 479, signal field (SIG) 481, another guard interval (GI) 483, third channel sounding (CS2, 2) 485, third guard interval (GI) 487, fourth channel sounding (CS2, 3) 489, guard interval (GI) 491 and fifth channel sounding (CS2,4) 495. The fourth preamble message 501 is sent through the fourth antenna, including a double guard interval (GI2) 503, the first channel sounding (CS3, 0) 505, the second channel sounding (CS3, 1) 507, the guard interval ( GI) 509, signal domain (SIG) 511, another guard interval (GI) 513, third channel sounding (CS3, 2) 515, third guard interval (GI) 517, fourth channel sounding (CS3, 3) 519, guard interval (GI) 521 and fifth channel sounding (CS3,4) 525.

To the embodiment of Fig. 17:

_θk = π·k/6

φ _k = π·(k+2)/6

ψ _k = π·(k+4)/6

In the running process of Fig. 15-17, different transmission modes on each subcarrier are formed by setting θ _k , φ _k , and ψ _k . Better channel estimation is determined by next-generation 802.11n devices because more energy needs to be transmitted. Further, for this signal format, next-generation receivers will perform simple zero-forcing (ZF) or MMSE channel estimation.

Such a channel estimation operation can be performed by using the following matrices for two, three and four antennas respectively:

${\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]<span\; class="notranslate">\; \&DoubleRightArrow;</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\left[\begin{array}{cc}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]$

${\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\left[\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}& \frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&CenterDot;</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}& \frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ \mathrm{<span\; class="notranslate">\; 1</span>}& \frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}& \frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&CenterDot;</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right]<span\; class="notranslate">\; \&DoubleRightArrow;</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="W\; T"\; filenames="C20051006740700351.png,C20051006740700431.png"\; state="\{\{state\}\}">W</figure-callout></span><figure-callout\; id="1"\; label="W\; T"\; filenames="C20051006740700351.png,C20051006740700431.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}^{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\left[\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}& \frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}& \frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&CenterDot;</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ \mathrm{<span\; class="notranslate">\; 1</span>}& \frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&CenterDot;</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}& \frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right]$

${\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\left[\begin{array}{cccc}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]<span\; class="notranslate">\; \&DoubleRightArrow;</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 4</span>}}\left[\begin{array}{cccc}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]$

Using these techniques, in the first embodiment, the channel can be estimated in terms of existing per-subcarrier antenna beamforming coefficients, which then need not be applied to the remaining transmitted symbols. The advantage provided by this embodiment is that no additional multiplication operation needs to be performed on the sender side, so that the LTRN sequence can be simply looked up in the table.

In the second embodiment, channel estimation can be performed without knowing the beamforming coefficient of each subcarrier antenna. According to this embodiment, the coefficients have to be applied in the remaining transmitted symbols. The benefit of this embodiment is that the receiver channel estimation is simple (few multiplication operations), but the transmitter needs to perform additional multiplication operations.

For the first embodiment, the following equation can be used (using the previous definition and L=M):

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}$

${\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; diag</span>}<span\; class="notranslate">\; (</span>\left[\begin{array}{cccc}\mathrm{<span\; class="notranslate">\; 1</span>}& {\mathrm{<span\; class="notranslate">\; e</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; 6</span>}}}& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; e</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; 6</span>}}}\end{array}\right]<span\; class="notranslate">\; )</span>$

For the second embodiment, the following equation can be used (using the previous definition and L=M):

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 00</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}$

Further refinement of the channel estimate is possible by replicating the entire M-length sequence p times. This refinement uses simple averaging. The overhead is the same as described on page 10 for the corresponding single-activation-emitter method, but the performance is high.

For backward compatibility with the case of preamble information, where the number of long training symbols is M+1, the longer training sequence consists of p*M+1 long training symbols. There are then P identical blocks of M symbols, identical to the first and second symbols at the antenna.

Fig. 18 is a schematic block diagram of the manner in which legacy version devices and next generation devices interpret the inclusion of backward compatible frame headers. To reduce receiver computational complexity, the configuration of the transmit antenna and preamble information 531 needs to be encoded into the legacy version of the signal field 533 . Another option is to let the receiver calculate 4 different channel estimates and then choose the configuration 535 of the antenna/preamble information so as to match the check digit and the only legal value in the SIGNAL2 (MIMO extension) field.

According to one aspect of the present invention, the transmit bit rate 537 is reinterpreted with "MIMO Interpretation" 539 if the reserved bit in the signal field is set. For MIMO receivers, this rate is determined to be fixed, it no longer specifies any actual rate. Alternatively, they may combine the Length field, which uniquely indicates the length of the frame within the symbol, with the Antenna/Preamble Information configuration to specify a fictitious rate.

For example, for 54Mbps, there are 27 possible digits of bytes in the length field to signify the duration of the same frame. These 27 possibilities can encode the TX antenna/preamble information configuration. In Table 1 below, three encodings are shown. Note that we can simply use the "6Mbps" rate to uniquely specify all length and tx antenna/preamble information configurations. In this case, other rate encodings will not be used if the reserved bit is set. The drawback of this approach is that we lose the ability to encode alternatives to the introductory information.

Table 1 - Rate Field Explanation

rate bits 802.11a interpretation (reserved bits = 0) MIMO Interpretation (reserved bit = 1) 1101 6Mbps Length mod 3=1=>2TX antenna length mod 3=2=>3TX antenna length mod 3=3=>4TX antenna 1111 9Mbps N/A 0101 12Mbps Length mod 6=1=>2TX antenna length mod 6=2=>3TX antenna length mod 6=3=>4TX antenna 0111 18Mbps Length mod 9 = 1 = > 2TX antenna length mod 9 = 2 = > 3TX antenna length mod 9 = 3 = > 4TX antenna 1001 24Mbps Length mod 12=1=>2TX antenna length mod 12=2=>3TX antenna length mod 12=3=>4TX antenna 1011 36Mbps Length mod 18=1=>2TX antenna length mod 18=2=>3TX antenna length mod 18=3=>4TX antenna 0001 48Mbps Length mod 24=1=>2TX antenna length mod 24=2=>3TX antenna length mod 24=3=>4TX antenna 0011 54Mbps Length mod 27＝1＝＞2TX antenna length mod 27＝2＝＞3TX antenna length mod 27＝3＝＞4TX antenna

Those skilled in the art can understand that the terms "substantially" and "approximately" are used herein to correspond to standards accepted by the industry. Acceptable tolerances in the industry range from less than 1% to less than 20% for items that correspond to, but are not limited to, component values, inherited circuit processing variations, temperature variations, ramp times, and/or thermal noise. Those skilled in the art can further understand that a term often used herein, "operably connected" includes direct connection or indirect connection through other components, components, circuits or modules. For direct connections, the intervening components, elements, circuits, or modules do not modify signals, but may adjust current levels, voltage levels, and/or power levels. Those skilled in the art can further understand that another term, an inferred connection (for example, one element is connected to another element by inference) includes direct or indirect connection between two elements connected in a manner similar to "operable connection". Further understood by those skilled in the art, another term, "compares favorably" may be used to indicate a comparison between two or more elements, items, signals, etc., to provide expected Relationship. For example, when the desired relationship is that signal 1 is an order of magnitude larger than signal signal 2, favorable comparison results can be obtained when signal 1 is an order of magnitude greater than signal 2 or when signal 2 is an order of magnitude smaller than signal 1.

Methods and apparatus for updating channel estimates based on the payload of signal frames have been revealed by discussion. Those of ordinary skill in the art will understand that other embodiments can be obtained without exceeding the scope of the claims.

Claims (7)

1, a kind of method that disposes multi-input and multi-output wireless communication is characterized in that, this method comprises:

Generation is used for a plurality of introduction information of a plurality of transmitting antennas, and each introduction information wherein comprises:

Detect sequence at the carrier wave of leaving on the version transmission rate;

At first channel detection of leaving on the version transmission rate;

In the signal domain of leaving on the version transmission rate; With

A plurality of channel detections on the MIMO transmission rate; With

Send described a plurality of introduction information by a plurality of transmitting antennas simultaneously, wherein, describedly leaving over first channel detection on the version transmission rate and each channel detection in described a plurality of channel detections on the MIMO transmission rate by with the number of this channel detection with transmit the corresponding weight factor weighting of introduction information emission antenna that comprises this channel detection.

2, method according to claim 1, wherein, described MIMO transfer rate comprises the transfer rate of leaving over version.

3, method according to claim 1 further comprises the described signal domain of generation, by:

Indicate the frame length of described MIMO wireless telecommunications, thereby the wireless telecommunications system of leaving over version can be provided with in the duration of MIMO wireless telecommunications and avoids conflict; With

The reservation position is set indicates described MIMO wireless telecommunications.

4, a kind of radio frequency integrated circuit reflector is characterized in that, comprising:

Exercisable connection is to produce the baseband processing module of a plurality of introduction information; With

By the radiofrequency launcher part that is operatively connected of a plurality of antennas described a plurality of introduction information of transmission on certain radio frequency, wherein, each the introduction information in a plurality of introduction information that described baseband processing module produces comprises:

Detect sequence at a carrier wave of leaving on the transmission rate of version;

At first channel detection of leaving on the transmission rate of version;

In the signal domain of leaving on the transmission rate of version; With

L-1 on a MIMO transmission rate channel detection, the wherein number of L respective channels detection;

Wherein, describedly leaving over first channel detection on the version transmission rate and each channel detection in described L-1 the channel detection on the MIMO transmission rate by with the number of this channel detection with transmit the corresponding weight factor weighting of introduction information emission antenna that comprises this channel detection.

5, radio frequency integrated circuit reflector according to claim 4, wherein said MIMO transmission rate comprises the transmission rate of leaving over version.

6, a kind of method that in the introduction information of wireless telecommunications, generates signal domain, this method comprises:

In signal domain, indicate the frame length of multiple-input and multiple-output MIMO wireless telecommunications, thereby the wireless telecommunications system of leaving over version can be provided with in the duration of MIMO wireless telecommunications and avoids conflict; With

The reservation position is set in signal domain indicates the MIMO wireless telecommunications;

Speed position and length position are set in signal domain, the speed of specify fabricating in described speed position and length position, wherein said imaginary speed indicate frame length, the configuration of transmitting antenna and the configuration of introduction information of the MIMO wireless telecommunications that are used to launch described introduction information.

7, a kind of radio frequency integrated circuit reflector is characterized in that, comprising:

Exercisable connection is to produce the baseband processing module of a plurality of introduction information; With

By the radiofrequency launcher part that is operatively connected of a plurality of antennas a plurality of introduction information of transmission on certain radio frequency, wherein, described baseband processing module generates signal domain on each introduction information:

In signal domain, indicate the frame length of multiple-input and multiple-output MIMO wireless telecommunications, thereby the wireless telecommunications system of leaving over version just can be provided with in the duration of MIMO wireless telecommunications and avoids conflict; With

The reservation position is set in signal domain indicates the MIMO wireless telecommunications;

Speed position and length position are set in signal domain, the speed of specify fabricating in described speed position and length position, wherein said imaginary speed indicate frame length, the configuration of transmitting antenna and the configuration of introduction information of the MIMO wireless telecommunications that are used to launch described introduction information.

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