PATENT DOCUMENT

Publication Number: US-11431540-B2
Application Number: US-202117166308-A
Country: US
Kind Code: B2

Title: Technologies for transmitting or receiving an aggregate physical layer protocol data unit

Abstract:
A transmission apparatus includes a signal generator which, in operation, generates a signal having an aggregate physical layer protocol data unit (PPDU) that includes a legacy preamble, a legacy header, a non-legacy preamble, a plurality of non-legacy headers and a plurality of data fields; and a transmitter which, in operation, transmits the generated signal, wherein the legacy preamble, the legacy header and the plurality of non-legacy headers are transmitted using a standard bandwidth, the non-legacy preamble and the plurality of data fields are transmitted using a variable bandwidth that is larger than the standard bandwidth and wherein a plurality of sets of each of the plurality of non-legacy headers and each of the plurality of data fields are transmitted sequentially in a time domain.

Claims:
What is claimed is: 
     
       1. An integrated circuit comprising:
 at least one input to receive a signal from a transmission apparatus; and 
 control circuitry coupled to the at least one input, the control circuitry to:
 receive the signal, the signal having an aggregate physical layer protocol data unit (PPDU) that has a first set and a second set, the first set having a plurality of first fields arranged in order of one or more first legacy fields, a first legacy header field, a first non-legacy header field, one or more first non-legacy fields, and a first data field on a time axis, the second set having a plurality of second fields arranged in order of a second non-legacy header field and a second data field on the time axis; and 
 decode the signal to generate decoded bits for the first data field or the second data field by using the first non-legacy header field and the one or more first non-legacy fields, 
 wherein the one or more first legacy fields, the first legacy header field, and the first non-legacy header field are transmitted using one stream, the first data field is transmitted using a plurality of streams, and the second data field is transmitted using at least two streams. 
 
 
     
     
       2. The integrated circuit according to  claim 1 , wherein the one or more first non-legacy fields comprise a non-legacy short training field (STF) or a plurality of non-legacy channel estimation fields (CEFs). 
     
     
       3. The integrated circuit according to  claim 1 , wherein the first non-legacy header field is generated as a single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol that is pre-pended by a first guard interval having a first length, and a final SC block in the first non-legacy header field is post-pended by a second guard interval having the first length. 
     
     
       4. The integrated circuit according to  claim 1 , wherein the first data field is generated as a single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol that is pre-pended by a first guard interval having a first length, and a final SC block in the first data field is post-pended by a second guard interval having the first length. 
     
     
       5. The integrated circuit according to  claim 1 , wherein aggregate PPDU has one or more second sets that include the second set, the second non-legacy header field is generated as a single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol that is pre-pended by a first guard interval having a first length, and a final SC block in a final non-legacy header field of the one or more second sets is post-pended by a second guard interval having the first length. 
     
     
       6. The integrated circuit according to  claim 3 , wherein symbols in the second guard interval are inverted. 
     
     
       7. The integrated circuit according to  claim 1 , wherein the one or more first legacy fields and the first legacy header field are associated with a first multi-gigabit wireless communication technology and the first non-legacy header field, the one or more first non-legacy fields, and the second non-legacy header field are associated with a second multi-gigabit wireless communication technology developed after the first multi-gigabit wireless communication technology. 
     
     
       8. The integrated circuit according to  claim 1 , wherein the one stream, the plurality of streams, and at least two streams are one space-time stream, a plurality of space-time streams, and at least two space-time streams, respectively. 
     
     
       9. An apparatus comprising:
 control circuitry to control generation of an aggregate physical layer protocol data unit (PPDU) having a plurality of first fields and a plurality of second fields, the plurality of first fields arranged in order of one or more first legacy fields, a first legacy header field, a first non-legacy header field, one or more first non-legacy fields, and a first data field, and the plurality of second fields arranged in order of a second non-legacy header field and a second data field; and 
 transmit circuitry, coupled to the control circuitry, to transmit aggregate PPDU, wherein the transmit circuitry is to transmit the one or more first legacy fields, the first legacy header field, and the first non-legacy header field as one stream, the first data field as a plurality of streams, and the second data field as at least two streams. 
 
     
     
       10. The apparatus according to  claim 9 , wherein the one or more first non-legacy fields comprise a non-legacy short training field (STF) or a plurality of non-legacy channel estimation fields (CEFs). 
     
     
       11. The apparatus according to  claim 9 , wherein the control circuitry is to generate the first non-legacy header field as a single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol that is pre-pended by a first guard interval having a first length, wherein a final SC block in the first non-legacy header field is post-pended by a second guard interval having the first length. 
     
     
       12. The apparatus according to  claim 11 , wherein symbols in the second guard interval are inverted. 
     
     
       13. The apparatus according to  claim 9 , wherein the control circuitry is to generate the first data field as a single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol that is pre-pended by a first guard interval having a first length, wherein a final SC block is post-pended by a second guard interval having the first length. 
     
     
       14. The apparatus according to  claim 9 , wherein aggregate PPDU has one or more sets that include the plurality of second fields and the control circuitry is to generate the first non-legacy header field as a single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol that is pre-pended by a first guard interval having a first length, wherein a final SC block in a final non-legacy header field of the one or more sets is post-pended by a second guard interval having the first length. 
     
     
       15. The apparatus according to  claim 9 , wherein the one or more first legacy fields and the first legacy header are associated with a first multi-gigabit wireless communication technology and the first non-legacy header field, the one or more first non-legacy fields, and the second non-legacy header field are associated with a second multi-gigabit wireless communication technology developed after the first multi-gigabit wireless communication technology. 
     
     
       16. The apparatus according to  claim 9 , wherein the one stream, the plurality of streams, and at least two streams are one space-time stream, a plurality of space-time streams, and at least two space-time streams, respectively. 
     
     
       17. One or more non-transitory, computer-readable media having instructions that, when executed by one or more processors, cause a device to:
 generate an aggregate physical layer protocol data unit (PPDU) having a plurality of first fields and a plurality of second fields, the plurality of first fields arranged in order of one or more first legacy fields, a first legacy header field, a first non-legacy header field, one or more first non-legacy fields, and a first data field, and the plurality of second fields arranged in order of a second non-legacy header field and a second data field; and 
 transmit aggregate PPDU, wherein, to transmit aggregate PPDU the device is to transmit the one or more first legacy fields, the first legacy header field, and the first non-legacy header field as one stream, the first data field as a plurality of streams, and the second data field as at least two streams. 
 
     
     
       18. The one or more non-transitory, computer-readable media according to  claim 17 , wherein the one or more first non-legacy fields comprise a non-legacy short training field (STF) or a plurality of non-legacy channel estimation fields (CEFs). 
     
     
       19. The one or more non-transitory, computer-readable media according to  claim 17 , wherein the one or more first legacy fields and the first legacy header field are associated with a first multi-gigabit wireless communication technology and the first non-legacy header field, the one or more first non-legacy fields, and the second non-legacy header field are associated with a second multi-gigabit wireless communication technology developed after the first multi-gigabit wireless communication technology. 
     
     
       20. The one or more non-transitory, computer-readable media according to  claim 17 , wherein the one stream, the plurality of streams, and at least two streams are one space-time stream, a plurality of space-time streams, and at least two space-time streams, respectively.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure generally pertains to wireless communications and, more particularly, to a method for formatting and transmitting an aggregate physical layer protocol data unit (PPDU) in a wireless communications system. 
     2. Description of the Related Art 
     Interest in unlicensed 60 GHz millimeter wave (mmW) networks is increasing. wireless Hi-Definition (HD) technology is the first 60 GHz mmW industry standard, which enables multi-gigabit wireless streaming of high-definition audio, video and data among consumer electronics, personal computer and portable products. Another multi-gigabit wireless communications technology operating over the 60 GHz mmW frequency band is WiGig technology, which has been standardized by the Institute of Electrical and Electronic Engineers (IEEE) as the IEEE 802.11ad standard (see IEEE 802.11ad-2012). 
     The WiGig technology supplements and extends the IEEE 802.11 media access control (MAC) layer and is backward compatible with the IEEE 802.11 wireless local area network (WLAN) standard. The WiGig MAC supports a centralized network architecture such as an infrastructure basic service set (BSS) or a personal BSS (PBSS), where only the central coordinator, e.g., an access point (AP) or personal BSS control point (PCP), transmits beacons to synchronize all stations (STAs) in the network. Rather than other IEEE 802.11 WLAN technologies operating over 2.4 GHz or 5 GHz frequency band, the WiGig technology makes extensive use of BF (beamforming) to achieve directional transmissions. 
     Due to a standard bandwidth of 2.16 GHz, the WiGig technology is able to offer a physical layer (PHY) data rate of up to 6.7 Gbps. The WiGig PHY supports both single carrier (SC) modulation and orthogonal frequency division multiplexing (OFDM) modulation. For the purpose of increasing transmission efficiency, the WiGig PHY also supports “aggregate PPDU”. In the context of SC modulation, the aggregate PPDU is a sequence of two or more SC PPDUs transmitted without inter-frame spacing (IFS), preamble and separation between PPDU transmissions. 
     A prevailing application of the WiGig technology is a cable replacement for wired digital interface. For example, the WiGig technology can be used to implement a wireless Universal Serial Bus (USB) link for instant synchronization between smart phones or tablets or a wireless High-Definition Multimedia Interface (HDMI) link for video streaming. The state-of-the-art wired digital interfaces (e.g., USB 3.5 and HDMI 1.3) enable data rates up to tens of Gbps and therefore the WiGig technology also needs to be evolved to match them. Techniques for supporting multiple input multiple output (MIMO) transmission with variable bandwidth while maintaining backward compatibility with existing (i.e., legacy) WiGig devices would be desirable for Next Generation 60 GHz (NG60) WiGig to achieve PHY data rates up to tens of Gbps. 
     In order to keep backward compatibility with legacy WiGig devices, the NG60 WiGig shall be able to support both legacy format (LF) PPDUs, defined in IEEE 802.11ad, with a standard bandwidth, and mixed format (MF) PPDUs with capability of accommodating MIMO transmission with variable bandwidth. A non-limiting embodiment contributes to providing a transmission format and a transmission method of aggregate MF PPDU in an efficient way such that transmission efficiency can be maximized. 
     SUMMARY 
     In one general aspect, the techniques disclosed here feature: a transmission apparatus including a signal generator which, in operation, generates a signal having an aggregate physical layer protocol data unit (aggregate PPDU) that includes a legacy preamble, a legacy header, a non-legacy preamble, a plurality of non-legacy headers and a plurality of data fields; and a transmitter which, in operation, transmits the generated signal, wherein the legacy preamble, the legacy header and the plurality of non-legacy headers are transmitted using a standard bandwidth, the non-legacy preamble and the plurality of data fields are transmitted using a variable bandwidth that is the same as or greater than the standard bandwidth, and a plurality of sets of each of the plurality of non-legacy headers and each of the plurality of data fields are transmitted sequentially in a time domain. 
     With the transmission apparatus and transmission method of aggregate MF PPDU of the present disclosure, transmission efficiency is maximized. 
     It should be noted that general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any selective combination thereof. 
     Additional benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. The benefits and/or advantages may be individually obtained by the various embodiments and features of the specification and drawings, which need not all be provided in order to obtain one or more of such benefits and/or advantages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating the format of an example SC PPDU according to the related art; 
         FIG. 2  is a diagram illustrating the fields of an example header according to the related art; 
         FIG. 3  is a block diagram illustrating an example transmitter for the header and the data field according to the related art; 
         FIG. 4  is a diagram illustrating the format of an example aggregate SC PPDU according to the related art; 
         FIG. 5  is a diagram illustrating the format of an example MF SC PPDU according to the present disclosure; 
         FIG. 6  is a diagram illustrating the content of an example NG60 header according to the present disclosure; 
         FIG. 7  is a block diagram illustrating an example Tx baseband processor for the NG60 header and the data field of the MF SC PPDU according to the present disclosure; 
         FIG. 8  is a diagram illustrating transmission of the example MF SC PPDU in a channel where channel bandwidth is two times of standard bandwidth according to the present disclosure; 
         FIG. 9  is a block diagram illustrating an example Rx baseband processor for receiving the MF SC PPDU according to the present disclosure; 
         FIG. 10A  illustrates the format of an example aggregate MF SC PPDU according to a first embodiment of the present disclosure; 
         FIG. 10B  illustrates the format of an example aggregate MF SC PPDU according to the first embodiment of the present disclosure; 
         FIG. 11  is a diagram illustrating transmission of the example aggregate MF SC PPDU in a channel where channel bandwidth is two times of standard bandwidth according to the first embodiment of the present disclosure; 
         FIG. 12  illustrates the format of an example aggregate MF SC PPDU according to a second embodiment of the present disclosure; 
         FIG. 13  is a diagram illustrating transmission of the example aggregate MF SC PPDU in a channel where channel bandwidth is two times of standard bandwidth according to the second embodiment of the present disclosure; 
         FIG. 14  illustrates the format of an example aggregate MF SC PPDU according to a third embodiment of the present disclosure; 
         FIG. 15  is a block diagram illustrating example architecture of a wireless communication apparatus according to the present disclosure; 
         FIG. 16  is a diagram illustrating the format of an example component aggregate MF SC PPDU where a plurality of aggregate MF SC PPDUs have further been aggregated, according to the first embodiment; and 
         FIG. 17  is a diagram illustrating transmission of an example component aggregate MF SC PPDU where a plurality of aggregate MF SC PPDUs have further been aggregated, on a channel where the channel bandwidth is two times the standard bandwidth, according to the first embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments of the present disclosure will now be described in detail with reference to the annexed drawings. In the following description, a detailed description of known functions and configurations incorporate herein has been omitted for clarity and conciseness. 
       FIG. 1  illustrates the format of an example SC PPDU  100  according to the related art. The SC PPDU  100  includes a short training field (STF)  101 , a channel estimation field (CEF)  103 , a header  112 , a data field  114  and optional AGC&amp;TRN-R/T subfields  115 . All the fields of the SC PPDU  100  are transmitted with a standard bandwidth of 2.16 GHz. 
     The STF  101  is used for packet detection, automatic gain control (AGC), frequency offset estimation and synchronization. The CEF  103  is used for channel estimation as well as indication of which of SC and OFDM modulations is going to be used for the SC PPDU  100 . The header  112  includes a plurality of fields that define the details of the SC PPDU  100  to be transmitted, as illustrated in  FIG. 2 . 
     The data field  114  includes the payload data of the SC PPDU  100 . The number of data octets in the data field  114  is specified by the Length field of the header  112 , and the MCS (Modulation and Coding Scheme) used by the data field  114  is specified by the MCS field of the header  112 . 
     The AGC&amp;TRN-R/T subfields  115  are present only when the PPDU  100  is used for the purpose of beam refinement or tracking. The length of AGC&amp;TRN-R/T subfields  115  is specified by the Training Length field of the header  112 . Whether TRN-R field or TRN-T field is present is specified by the Packet Type field of the header  112 . 
       FIG. 3  is a block diagram illustrating an example transmitter  300  for the header  112  and the data field  114  according to the related art. The transmitter  300  includes a scrambler  302 , a low density parity check (LDPC) encoder  304 , a modulator  306  and a symbol blocking and guard Insertion block  308 . The scrambler  302  scrambles the bits of the header  112  and the data field  114 . Note that a shift register included in the scrambler  302  is initialized according to the scrambler Initialization field of the header  112 . The header  112  is scrambled starting from the bits of the MCS field following the scrambler Initialization field. 
     In the context of the header  112 , the LDPC encoder  304  performs LDPC encoding on the scrambled bits of the header  112  according to a predetermined code rate and generates a sequence of coded bits. The modulator  306  converts the sequence of coded bits into a plurality of complex constellation points using π/2 binary phase shift keying (BPSK). The symbol blocking and guard Insertion block  308  generates two SC blocks from the plurality of complex constellation points. Each SC block (e.g.,  132 ) includes 448 π/2-BPSK data symbols and is prepended by a guard interval  131  of 64 π/2-BPSK symbols generated from the predefined Golay sequence of length 64. 
     In the context of the data field  114 , the LDPC encoder  304  performs LDPC encoding on the scrambled bits of the data field  114  according to a code rate which is specified by the MCS field of the header  112 . The LDPC encoder  304  generates a sequence of coded bits, followed by padding bits if necessary. The modulator  306  converts the coded and padded bit stream into a stream of complex constellation points according to the modulation scheme specified by the MCS field of the header  112 . The symbol blocking and guard Insertion block  308  generates a plurality of SC blocks from the stream of complex constellation points. Each SC block (e.g.,  142 ) includes 448 data symbols and is prepended by the same guard interval  131 . Furthermore, the final SC block  144  transmitted needs to be followed by the same guard interval  131  for ease of SC frequency domain equalization (FDE). 
       FIG. 4  illustrates the format of an example aggregate SC PPDU  400  according to the related art. The aggregate PPDU  400  includes four constituent SC PPDUs. Each of the four PPDUs in the aggregate SC PPDU  400  includes a header and a data field. For example, the PPDU  410  includes a header  412  and a data field  414 . In addition, the PPDU  410  which is located at the beginning of the aggregate SC PPDU  400  includes the STF  401  and the CEF  403  as well. And the SC PPDU  440  which is located at the end of the aggregate SC PPDU  400  includes optional AGC &amp; TRN-R/T subfields  445  as well. Notice that there are no IFS, preamble and separation between PPDU transmissions in the aggregate SC PPDU  400 . 
     According to the related art, the STF  401 , the CEF  403 , each of the headers (e.g.,  412 ), each of the data fields (e.g.,  414 ) and the AGC&amp;TRN-T/R subfield  445  in the aggregate SC PPDU  400  are defined in the exactly same manner as their respective counterparts in the SC PPDU  100  in  FIG. 1 . 
     According to the related art, the final SC block transmitted as a data field, except the last data field  444 , is followed by the first SC block transmitted as a header. So, only the final SC block  452  within the last SC PPDU  440  needs to be post-pended by the same guard interval  131 . 
       FIG. 5  illustrates the format of an example of MF SC PPDU  500  according to the present disclosure. The MF PPDU  500  includes a legacy STF  501 , a legacy CEF  503 , a legacy header  505 , a NG60 header  512 , a NG60 STF  507 , a plurality of NG60 CEFs  509 , a data field  514  and optional AGC&amp;TRN-R/T subfields  515 . 
     The legacy STF  501 , the legacy CEF  503  and the legacy header  505  are defined in the exactly same manner as their respective counterparts in  FIG. 1 . 
     The NG60 header  512  defines the details of the MF SC PPDU  500  to be transmitted. The example fields of the NG60 header  512  are illustrated in  FIG. 6 . The data field  514  consists of the payload data of the MF SC PPDU  500 . Space-time block coding (STBC) or MIMO spatial multiplexing may be applied to the data field  514 , which results in a plurality of space-time streams (STSs) in the data field  514 . The number of STSs in the data field  514  is specified in the N sts  field of the NG60 header  512 . 
     The NG60 STF  507  is used for retraining AGC only. The plurality of NG60 CEFs  509  is used for channel estimation for the plurality of STSs in the data field  514 . Note that the number of NG60 CEFs  509  depends on the number of STSs in the data field  514 . In one embodiment, the number of NG60 CEFs  509  shall not be smaller than the number of STSs in the data field  514 . For example, if the number of STSs in the data field  514  is 2, the number of NG60 CEFs  509  can be set to 2. If the number of STSs in the data field  514  is 3, the number of NG60 CEFs  509  can be set to 4. 
       FIG. 7  is a block diagram illustrating an example Tx baseband processor  700  for the NG60 header  512  and the data field  514  of the MF SC PPDU  500 . The Tx baseband processor  700  includes a scrambler  702 , a LDPC encoder  704 , a modulator  706 , a MIMO encoder  708  and a symbol blocking and guard Insertion block  710 . The modulator  706  includes a first modulation functional block  712 , a second modulation functional block  714  and a third modulation functional block  716 . 
     The bits of the NG60 header  512  are prepended to the bits of the data field  514  and passed into the scrambler  702 . The scrambler  702  scrambles the bits of the NG60 header  512  and the data field  514  according to a predefined scrambling rule. Note that the shift register included in the scrambler  702  is initialized according to the scrambler Initialization field in the NG60 header  512 . The NG60 header  512  is scrambled starting from the bits of the MCS field following the scrambler Initialization field, and the scrambling of the data field  514  follows the scrambling of the NG60 header  512  with no reset. 
     In the context of the NG60 header  512 , the LDPC encoder  704  performs LDPC encoding on the scrambled bits of the NG60 header  512  according to a predetermined code rate and generates a sequence of coded bits. The second modulation functional block  714  inside the modulator  706  converts the sequence of coded bits into a stream of complex constellation points using π/2-BPSK with a phase rotation of 90 degrees. The symbol blocking and guard Insertion block  710  generates two SC blocks from the stream of complex constellation points. Each SC block includes 448 data symbols and is prepended by the same guard interval  131 . In addition, the final SC block  532  within the NG60 header  512  needs to be followed by the same guard interval  131 . 
     In the context of the data field  514 , the LDPC encoder  704  performs LDPC encoding on the scrambled bits of the data field  514  according to a code rate which is specified by the MCS field of the NG60 header  512  and generates a sequence of coded bits, followed by padding bits if necessary. The third modulation functional block  716  in the modulator  706  converts the coded and padded bit stream into a stream of complex constellation points according to the modulation scheme specified by the MCS field of the NG60 header  512 . Notice that the first modulation functional block  712  inside the modulator  706  is used for the modulation of the legacy header  505 . Which one of the first modulation functional block  712 , the second modulation functional block  714  and the third modulation functional block  716  inside the modulator  706  is used is determined according to a control signal generated by the controller  1502  as illustrated in  FIG. 15 . The MIMO encoder  708  applies the MIMO encoding to the stream of complex constellation points and obtains a plurality of STSs  550 . For each STS, the symbol blocking and guard Insertion block  710  generates a plurality of SC blocks. The number of SC blocks per STS is the same. Each SC block (e.g.,  542 ) includes N 1  data symbols and is prepended by a guard interval  541  of N 2  π/2-BPSK symbols generated from the predefined Golay sequence of length N 2 , where N 1  and N 2  are positive integers and N 1  should be an integer multiple of N 2 . The values of N 1  and N 2  may be configurable and indicated in the NG60 header  512 . Furthermore, for each STS, the final SC block transmitted needs to be followed by the same guard interval  541 . 
     According to the present disclosure, since the legacy header  505  of the MF SC PPDU  500  has the exactly same format and Tx processing as the header  112  of the SC PPDU  100 , a legacy WiGig device is able to decode the legacy header  505  of the MF SC PPDU  500  correctly. 
     According to the present disclosure, the NG60 header  512  of the MF SC PPDU  500  is modulated using π/2-BPSK with a phase rotation of 90 degrees, which is different from a phase rotation of the legacy header  505 . Due to such modulation difference, a NG60 device is able to determine whether the received SC PPDU is MF or LF. 
     According to the present disclosure, a legacy WiGig device would process the received MF SC PPDU  500  in the same manner as the SC PPDU  100 . In other words, the legacy WiGig device would envision the NG60 header  512 , the NG60 STF  507  and the NG60 CEFs  509  as a part of the PHY service data unit (PSDU). In order for the legacy WiGig device to determine the actual transmission time of the PSDU correctly, the values of the MCS field and the Length field of the legacy header  505  shall be appropriately set. 
     According to the present disclosure, a NG60 device is able to know the channel bandwidth information only after it successfully decodes the NG60 header  512 . As a result, the NG60 STF  507 , the plurality of NG60 CEFs  509 , the data field  514  and the optional AGC&amp;TRN-R/T subfields  515  can be transmitted with variable bandwidth. However, the legacy STF  501 , the legacy CEF  503 , the legacy header  505  and the NG60 header  512  can be transmitted with standard bandwidth only. In a channel with a channel bandwidth of M multiples of standard bandwidth, M copies of the legacy STF  501 , the legacy CEF  503 , the legacy header  505  and the NG60 header  512  can be transmitted with standard bandwidth in the channel simultaneously after an appropriate frequency offset is applied to each of these M copies.  FIG. 8  is a diagram illustrating transmission of the MF SC PPDU  500  in a channel where channel bandwidth is two times of standard bandwidth. As shown in  FIG. 8 , the frequency offset for the original legacy STF, legacy CEF, legacy header and NG60 header can be set to 50% of standard bandwidth and the frequency offset for the duplicated legacy STF, legacy CEF, legacy header and NG60 header can be set to −50% of standard bandwidth. 
       FIG. 9  is a block diagram illustrating an example Rx baseband processor  900  for receiving the MF SC PPDU  500  according to the present disclosure. The Rx baseband processor  900  includes a symbol unblocking and guard removal block  902 , a MIMO decoder  904 , a demodulator  906 , a LDPC decoder  908 , a descrambler  910  and a channel estimator  912 . Note that the MIMO Decoder  904  is only applicable to decoding of the data field  514 . 
     The symbol unblocking and guard removal block  902  performs the inversion operation with respect to the symbol blocking and guard insertion block  710  on the received SC MF PPDU  500 . 
     The NG60 header  512  needs to be decoded first. For this purpose, the demodulator  906  performs the inversion operation with respect to the modulator  706  based on the channel estimates obtained by the channel estimator  912  from the legacy CEF  503 . In more details, the second demodulation functional block  916  is applied to the portion corresponding to the NG60 header  512 . After that the LDPC Decoder  908  and the descrambler  910  perform the inversion operation with respect to the LDPC encoder  704  and the scrambler  702 , respectively, resulting in the decoded bits of the legacy header  505  and the NG60 header  512 . 
     After decoding the NG60 header  512 , the Rx baseband processor  900  proceeds to decode the data field  514  based on the information of the NG60 header  512 . The MIMO Decoder  904  performs the inversion operation with respect to the MIMO encoder  708  on the portion of the received MF SC PPDU  500  corresponding to the data field  514  based on the channel estimates obtained by the channel estimator  912  from the NG60 CEFs  509 . The demodulator  906  performs the inversion operation with respect to the modulator  706 . In more details, the third demodulation functional block  918  is applied to the portion corresponding to the data field  514 . Notice that the first demodulation functional block  914  inside the demodulator  906  is used for the demodulation of the received legacy header  505 . Which one of the first demodulation functional block  914 , the second demodulation functional block  916  and the third demodulation functional block  918  is used is determined according to a control signal generated by the controller  1502  as shown in  FIG. 15 . After that the LDPC Decoder  908  and the descrambler  910  perform the inversion operation with respect to the LDPC encoder  704  and the scrambler  702 , respectively, resulting in the decoded bits of the data field  514 . 
     First Embodiment 
       FIGS. 10 a  and 10 b    illustrate a format of an example of an aggregate MF SC PPDU  1000  according to a first embodiment of the present disclosure. The aggregate MF SC PPDU  1000  includes four MF SC PPDUs. Each of the four MF SC PPDUs includes a NG60 header and a data field. For example, the first MF SC PPDU  1010  includes a NG60 header  1012  and a data field  1014 . The first MF SC PPDU  1010  which is located at the beginning of the aggregate MF SC PPDU  1000  further includes a legacy STF  1001 , a legacy CEF  1003 , a legacy header  1005 , a NG60 STF  1007  and a plurality of NG60 CEFs  1009 . The second MF SC PPDU  1020  which is located next to the first MF SC PPDU  1010  includes a NG60 header  1022  and a data field  1024 . The last MF SC PPDU  1040  which is located at the end of the aggregate MF SC PPDU  1000  further includes optional AGC &amp; TRN-R/T subfields  1045 . Notice that there are no IFS, preamble and separation between MF PPDU transmissions in the aggregate MF SC PPDU  1000 . So compared with individual transmission of normal MF SC PPDUs  500 , transmission efficiency is improved. 
     According to the first embodiment of the present disclosure, all of the data fields in the aggregate MF SC PPDU  1000  have the same transmission bandwidth. In one embodiment, the number of STSs N sts  for the data fields in the aggregate MF SC PPDU  1000  may be different. For example, as shown in  FIG. 10A , each of the data field  1014  and the data field  1044  has two STSs, while the data field  1024  has a single STS and the data field  1034  has three STSs. In this case, the number of NG60 CEFs  1009  depends on the maximum number of STSs among all of the data fields in the aggregate MF SC PPDU  1000 . For example, if the maximum number of STSs among all of the data fields is 2, the number of NG60 CEFs  1009  can be set to 2. If the maximum number of STSs among all of the data fields is 3, the number of NG60 CEFs  1009  can be set to 4. In another embodiment, the number of STSs N sts  for the data fields in the aggregate MF SC PPDU  1000  may be the same. For example, as shown in  FIG. 10B , each of the data fields has two STSs. 
     According to the first embodiment of the present disclosure, the NG60 STF  1007 , the plurality of NG60 CEFs  1009 , each of the data fields (e.g.,  1014 ) and the optional AGC &amp; TRN-R/T subfields  1045  can be transmitted with variable bandwidth. However, the legacy STF  1001 , the legacy CEF  1003 , the legacy header  1005  and each of the NG60 headers (e.g.,  1012 ) can be transmitted with standard bandwidth only.  FIG. 11  is a diagram illustrating transmission of the aggregated MF SC PPDU  1000  in a channel where channel bandwidth is two times of standard bandwidth. As shown in  FIG. 11 , each of the original legacy STF, the original legacy CEF, the original legacy header and all of the original NG60 headers are duplicated in a frequency domain. Here, the frequency offset for the original legacy STF, the original legacy CEF, the original legacy header and all of the original NG60 headers can be set to 50% of the standard bandwidth. And the frequency offset for the duplicated legacy STF, the duplicated legacy CEF, the duplicated legacy header and all of the duplicated NG60 headers can be set to −50% of the standard bandwidth. 
     According to the first embodiment of the present disclosure, for all of the data fields in the aggregate MF SC PPDU  1000 , each SC block includes the same number of data symbols and is prepended by the same guard interval  1051 . 
     According to the first embodiment of the present disclosure, since a NG60 header may have a transmission bandwidth different from a transmission bandwidth of its following data field, the final SC block transmitted as every NG60 header in the aggregate MF SC PPDU  1000  needs to be followed by the same guard interval  131 . Consequently, the number of required post-pended guard intervals for the NG60 headers is 4. The final SC block per STS transmitted of every data field in the aggregate MF SC PPDU  1000  needs to be followed by the same guard interval  1051 . Consequently, the number of required post-pended guard intervals for the data fields is 8. 
     According to the first embodiment of the present disclosure, the Tx baseband processor  700  for transmitting the MF SC PPDU  500  can be easily adapted for transmitting the aggregate MF SC PPDU  1000 . Similarly, the Rx baseband processor  900  for receiving the MF SC PPDU  500  can be easily adapted for receiving the aggregated MF SC PPDU  1000 . Notice that the channel estimates obtained by the channel estimator  912  from the legacy CEF  1003  can be used for decoding all of the NG60 headers  1012 ,  1022 ,  1032  and  1042  in the received aggregate MF SC PPDU  1000 . 
     The channel estimates obtained by the channel estimator  912  from the NG60 CEFs  1009  can be used for decoding all of the data fields  1014 ,  1024 ,  1034  and  1044  in the received aggregate MF SC PPDU  1000 . As a result, compared with individual transmission and reception of normal MF PPDUs  500 , transmission and reception of the aggregate MF SC PPDU  1000  does not incur extra implementation complexity. 
     According to the first embodiment of the present disclosure, a legacy STA is able to decode the legacy header  1005  but cannot decode the remaining of the aggregate MF SC PPDU  1000 . In order for the legacy STA to estimate transmission time of the aggregated MF SC PPDU  1000  correctly to avoid packet collision, the additional PPDU field in the legacy header  1016  shall be set to 0. In other words, the aggregate MF SC PPDU  1000  shall be envisioned by the legacy STA as a normal legacy PPDU  100  instead of legacy aggregate SC PPDU  400 . In addition, the MCS field and the Length field in the legacy header  1005  shall be appropriately set so that the transmission time calculated by the legacy STA is the same as the actual transmission time of the equivalent data field, which includes the NG60 STF  1007 , the NG60 CEFs  1009 , all of the NG60 headers and all of the data fields in the aggregate MF SC PPDU  1000 . In other words, a total packet length of the NG60 STF  1007 , the NG60 CEFs  1009 , all of the NG60 headers and all of the data fields is set as the Length field in the legacy header  1005 . 
     According to the first embodiment of the present disclosure, a legacy STA is able to calculate the actual transmission time of the equivalent data field of the aggregate MF SC PPDU  1000 , by decoding the legacy header  1005 . Accordingly, in a case where the clock frequency error between the central coordinator such as an access point or PCP and a legacy STA is extremely small, the additional PPDU field in the legacy header  1005  can be set to 1. 
       FIG. 16  is a diagram illustrating the format of aggregate MF SC PPDU  1600  where a plurality of (e.g., two) component aggregate MF SC PPDUs of which the data fields all have the same transmission bandwidth, have been linked. As illustrated in  FIG. 16 , the aggregate MF SC PPDU  1600  includes a first component aggregate MF SC PPDU  1610  located at the beginning, and a second component aggregate MF SC PPDU  1620  located at the end. The first component aggregate MF SC PPDU  1610  includes a first MF SC PPDU  1610 - 1  located at the beginning, and a second MF SC PPDU  1610 - 2  located at the end. The second component aggregate MF SC PPDU  1620  includes a third MF SC PPDU  1620 - 1  located at the beginning, and a fourth MF SC PPDU  1620 - 2  located at the end. Each of the MF SC PPDUs  1610 - 1 ,  1610 - 2 ,  1620 - 1 , and  1620 - 2  includes an NG60 header and data field. For example, the first MF SC PPDU  1610 - 1  includes an NG60 header  1612  and data field  1614 . The first MF SC PPDU  1610 - 1  further includes a legacy STF  1601 , legacy CEF  1603 , legacy header  1605 , NG60 STF  1607 , and a plurality of NG60 CEFs  1609 . The third MF SC PPDU  1620 - 1  further includes a legacy header  1635 , an NG60 STF  1637 , and a plurality of NG60 CEFs  1639 . The fourth MF SC PPDU  1620 - 2  further includes optional AGC&amp;TRN-R/T subfields  1645 . Notice that there are no IFS, preamble and separation between component aggregate MF SC PPDU transmissions in the aggregate MF SC PPDU  1600 . 
       FIG. 17  is a diagram illustrating transmission of the aggregate MF SC PPDU  1600  on a channel where the channel bandwidth is two times the standard bandwidth. The original legacy STF, original legacy CEF, original legacy header, and original NG60 header are each duplicated in the frequency region, as illustrated in  FIG. 17 . Accordingly, the frequency offset as to the original legacy STF, original legacy CEF, original legacy header, and all original NG60 headers, can be set to 50% of the standard bandwidth. Further, the frequency offset as to the duplicated legacy STF, duplicated legacy CEF, duplicated legacy header, and all duplicated NG60 headers, can be set to −50% of the standard bandwidth. 
     The ideas and concepts disclosed in this embodiment can be implemented for formatting and transmission of MF OFDM PPDUs. 
     Second Embodiment 
       FIG. 12  illustrates the format of another example of an aggregate MF SC PPDU  1200  according to a second embodiment of the present disclosure. The aggregate SC PPDU  1200  includes four MF SC PPDUs  1210 ,  1220 ,  1230  and  1240 . Each of the four MF SC PPDUs includes a NG60 header and a data field. For example, the MF SC PPDU  1210  includes a NG60 header  1212  and a data field  1214 . The first MF SC PPDU  1210  which is located at the beginning of the aggregate MF SC PPDU  1200  further includes a legacy STF  1201 , a legacy CEF  1203 , a legacy header  1205 , a NG60 STF  1207  and a plurality of NG60 CEFs  1209 . The last SC MF SC PPDU  1240  which is located at the end of the aggregate MF SC PPDU  1200  further includes optional AGC&amp;TRN-R/T subfields  1245 . Notice that there are no IFS, preamble and separation between MF SC PPDU transmissions in the aggregate MF SC PPDU  1200 . So compared with individual transmission of normal MF SC PPDUs  500 , transmission efficiency is improved. 
     According to the second embodiment of the present disclosure, besides the same transmission bandwidth, all of the data fields in the aggregate MF SC PPDU  1200  have the same number of STSs. For example, as shown in  FIG. 12 , every data field in the aggregate MF SC PPDU  1200  has two STSs. 
     According to the second embodiment of the present disclosure, for all of the data fields in the aggregate MF SC PPDU  1200 , each SC block includes the same number of data symbols and is prepended by the same guard interval  1251 . 
     According to the second embodiment of the present disclosure, all of the NG60 headers are located together right before the NG60 STF  1207 . Consequently, only the final SC block that is transmitted as the last NG60 header  1242  in the aggregate MF SC PPDU  1200  needs to be followed by the same guard interval  131 . In other words, the number of required post-pended guard intervals for the NG60 headers is 1. In addition, all of the data fields are also located together right after the NG60 CEFs  1209 . Therefore, only the final SC block per STS transmitted in the last data field  1244  in the aggregate MF SC PPDU  1200  needs to be followed by the same guard interval  1251  as the one preceding the last data field  1244 . In other words, the number of required post-pended guard intervals for the data fields is 2. 
     According to the second embodiment of the present disclosure, compared with the first embodiment, due to the less number of guard intervals required, the transmission efficiency is further improved. Furthermore, since there is no need of changing the sampling rate so frequently, Tx and Rx processing is simplified and implementation complexity is further improved. 
     According to the second embodiment of the present disclosure, the NG60 STF  1207 , the plurality of NG60 CEFs  1209 , each of the data fields (e.g.,  1214 ) and the optional AGC &amp; TRN-R/T subfields  1245  can be transmitted with a variable bandwidth. However, the legacy STF  1201 , the legacy CEF  1203 , the legacy header  1205  and each of the NG60 headers (e.g.,  1212 ) can be transmitted with the standard bandwidth only.  FIG. 13  is a diagram illustrating transmission of the aggregated MF SC PPDU  1200  in a channel where its channel bandwidth is two times of standard bandwidth. As shown in  FIG. 13 , each of the original legacy STF, the original legacy CEF, the original legacy header and all of the original NG60 headers are duplicated in a frequency domain. Here, the frequency offset for the original legacy STF, the original legacy CEF, the original legacy header and all of the original NG60 headers can be set to 50% of the standard bandwidth and the frequency offset for the duplicated legacy STF, the duplicated legacy CEF, the duplicated legacy header and all of the duplicated NG60 headers can be set to −50% of the standard bandwidth. 
     According to the second embodiment of the present disclosure, the Tx baseband processor  700  for transmitting the MF SC PPDU  500  can be easily adapted for transmitting the aggregate MF SC PPDU  1200  because switching of the transmission bandwidth is unnecessary. For the same reason, the Rx baseband processor  900  for receiving the MF SC PPDU  500  can be easily adapted for receiving the aggregated MF SC PPDU  1200 . Notice that the channel estimates obtained by the channel estimator  912  from the legacy CEF  1203  can be used for decoding all of the NG60 headers  1212 ,  1222 ,  1232  and  1242  in the received aggregate MF SC PPDU  1200 . The channel estimates obtained by the channel estimator  912  from the NG60 CEFs  1209  can be used for decoding all of the data fields  1214 ,  1224 ,  1234  and  1244  in the received aggregate MF SC PPDU  1200 . In addition, due to separation of a NG60 header and its corresponding data field, there is a need for storing the useful information of all of the NG60 headers for decoding all of the data fields. However, the required memory size may be trivial since the useful information of a NG60 header is small (about 7 bytes). As a result, compared with individual transmission and reception of normal MF SC PPDUs  500 , transmission and reception of the aggregate MF SC PPDU  1200  does not increase implementation complexity significantly. 
     According to the second embodiment of the present disclosure, a legacy STA is able to decode the legacy header  1205  but cannot decode the remaining of the aggregate MF SC PPDU  1200 . In order for the legacy STA to estimate transmission time of the aggregated MF SC PPDU  1200  correctly to avoid packet collision, the additional PPDU field in the legacy header  1205  shall be set to 0. In other words, the aggregate SC MF PPDU  1200  shall be envisioned by the legacy STA as a normal legacy SC PPDU  100  instead of legacy aggregate SC PPDU  400 . In addition, the MCS field and the Length field in the legacy header  1205  shall be appropriately set so that the transmission time calculated by the legacy STA is the same as the actual transmission time of the equivalent data field, which includes the NG60 STF  1207 , the NG60 CEFs  1209 , all of the NG60 headers and all of the data fields in the aggregate MF vPPDU  1200 . In other words, a total packet length of the NG60 STF  1207 , the NG60 CEFs  1209 , all of the NG60 headers  1212 ,  1222 ,  1232  and  1242  and all of the data fields  1214 ,  1224 ,  1234  and  1244  is set as the Length field in the legacy header  1205 . 
     According to the second embodiment of the present disclosure, symbols may be inverted in the guard interval following the final SC block of every MF SC PPDU in the aggregate MF SC PPDU  1200 . Inverting symbols can be performed by replacing bit  0  and bit  1  with bit  1  and bit  0 , respectively. Consequently, the receiver can easily determine the boundary between neighboring data fields so that it can decode a data field even if some of NG60 headers preceding the NG60 header corresponding to the data field are lost. 
     The ideas and concepts disclosed in this embodiment can be implemented for formatting and transmission of MF OFDM PPDUs. 
     Third Embodiment 
       FIG. 14  illustrates the format of another example of aggregate MF SC PPDU  1400  according to a third embodiment of the present disclosure. The aggregate MF SC PPDU  1400  includes four MF SC PPDUs  1410 ,  1420 ,  1430  and  1440 . Each of the four MF SC PPDUs includes a NG60 header and a data field. For example, the MF SC PPDU  1410  includes a NG60 header  1412  and a data field  1414 . The MF SC PPDU  1420  which is located at the beginning of the aggregate MF PPDU  1400  further includes a legacy STF  1401 , a legacy CEF  1403 , a legacy header  1405 , a NG60 STF  1407 , a plurality of NG60 CEFs  1409  and a data field  1424 . The MF SC PPDU  1430  which is located at the end of the aggregate MF SC PPDU  1400  includes a NG60 header  1432  and a data field  1434  and further includes optional AGC&amp;TRN-R/T subfields  1435 . Notice that there are no IFS, preamble and separation between MF SC PPDU transmissions in the aggregate MF SC PPDU  1400 . So compared with individual transmission of normal MF SC PPDUs, transmission efficiency is improved. 
     As is apparent from  FIG. 14 , all of the NG60 headers are located together right before the NG60 STF  1407 . Consequently, only the final SC block that is transmitted as the last NG60 header  1432  in the aggregate MF PPDU  1400  needs to be followed by the same guard interval  131 . In other words, the number of required post-pended guard intervals for the NG60 headers is 1. In addition, all of the data fields are also located together right after the NG60 CEFs  1409 . Therefore, only the final SC block per STS transmitted in the last data field  1434  in the aggregate MF SC PPDU  1400  needs to be followed by the same guard interval  1451  as the one preceding the final SC block. The number of required post-pended guard intervals for the data fields is 3 in  FIG. 14 . 
     According to the third embodiment of the present disclosure, all of the data fields in the aggregate MF SC PPDU  1400  have the same transmission bandwidth. However, other transmission parameters (e.g., the number of STSs N sts ) for the data fields in the aggregate MF SC PPDU  1400  may be different. For example, as shown in  FIG. 14 , each of the data field  1414  and the data field  1444  has two STSs, while the data field  1424  has a single STS and the data field  1434  has three STSs. The number of NG60 CEFs  1409  depends on the maximum number of STSs among all of the data fields in the aggregate MF SC PPDU  1400 . For example, if the maximum number of STSs among all of the data fields is 2, the number of NG60 CEFs  1409  can be set to 2. If the maximum number of STSs among all of the data fields is 3, the number of NG60 CEFs  1409  can be set to 4. 
     According to the third embodiment of the present disclosure, for all of the data fields in the aggregate MF SC PPDU  1400 , each SC block includes the same number of data symbols and is prepended by the same guard interval  1451 . 
     According to the third embodiment of the present disclosure, all of the NG60 headers are located together right before the NG60 STF  1407  in increasing order of the number of STSs which their corresponding data fields have. For example, as shown in  FIG. 14 , the NG60 header  1422  is located immediately after the legacy header  1405 , followed by the NG60 header  1412  and the NG60 header  1442  as well as the NG60 header  1432  in this order. Alternatively, all of the NG60 headers are located together right before the NG60 STF  1407  in decreasing order of the number of STSs which their corresponding data fields have. Notice that only the final SC block transmitted of the NG60 header  1432  in the aggregate MF SC PPDU  1400  needs to be followed by the same guard interval  131  as inserted before. In other words, the number of required post-pended guard intervals for the NG60 headers is 1. 
     According to the third embodiment of the present disclosure, all of the data fields are located together right after the NG60 CEFs  1409  in the same order as the NG60 headers. For example, as shown in  FIG. 14 , the data field  1424  is located immediately after the NG60 CEFs  1409 , followed by the data field  1414  and the data field  1444  as well as the data field  1434 . Based on such arrangement of the data fields, only the final SC block per STS transmitted of the last data field  1434  in the aggregate MF SC PPDU  1400  needs to be followed by the same guard interval  1451 . In other words, the number of required post-pended guard intervals is 3. 
     According to the third embodiment of the present disclosure, compared with the first embodiment, due to the less number of guard intervals required, the transmission efficiency is further improved. Furthermore, since there is no need of changing the sampling rate so frequently, TX/RX processing is simplified and implementation complexity is further improved. 
     According to the third embodiment of the present disclosure, the NG60 STF  1407 , the plurality of NG60 CEFs  1409 , each of the data fields (e.g.,  1414 ) and the optional AGC &amp; TRN-R/T subfields  1435  can be transmitted with variable bandwidth. However, the legacy STF  1401 , the legacy CEF  1403 , the legacy header  1405  and each of the NG60 headers (e.g.,  1412 ) can be transmitted with standard bandwidth only.  FIG. 13  is a diagram illustrating transmission of the aggregated MF SC PPDU  1400  in a channel where channel bandwidth is two times of standard bandwidth. 
     According to the third embodiment of the present disclosure, the Tx baseband processor  700  for transmitting the MF SC PPDU  500  can be easily adapted for transmitting the aggregate MF SC PPDU  1400 . Similarly, the Rx baseband processor  900  for receiving the MF SC PPDU  500  can be easily adapted for receiving the aggregated MF SC PPDU  1400 . Notice that the channel estimates obtained by the channel estimator  912  from the legacy CEF  1403  can be used for decoding all of the NG60 headers  1412 ,  1422 ,  1432  and  1442  in the received aggregate MF SC PPDU  1400 . The channel estimates obtained by the channel estimator  912  from the NG60 CEFs  1409  can be used for decoding all of the data fields  1414 ,  1424 ,  1434  and  1444  in the received aggregate MF SC PPDU  1400 . In addition, due to separation of a NG60 header and its corresponding data field, there is a need for storing the useful information of all of the NG60 headers for decoding all of the data fields. However, the required memory size may be trivial since the useful information of a NG60 header is small (about 7 bytes). As a result, compared with individual transmission and reception of normal MF SC PPDUs  500 , transmission and reception of the aggregate MF SC PPDU  1400  does not increase implementation complexity significantly. 
     According to the third embodiment of the present disclosure, a legacy STA is able to decode the legacy header  1405  but cannot decode the remaining of the aggregate MF SC PPDU  1400 . In order for the legacy STA to estimate transmission time of the aggregated MF SC PPDU  1400  correctly to avoid packet collision, the additional PPDU field in the legacy header  1405  shall be set to 0. In other words, the aggregate MF SC PPDU  1400  shall be envisioned by the legacy STA as a normal legacy SC PPDU  100  instead of legacy aggregate SC PPDU  400 . In addition, the MCS field and the Length field in the legacy header  1405  shall be appropriately set so that the transmission time calculated by the legacy STA is the same as the actual transmission time of the equivalent data field, which includes the NG60 STF  1407 , the NG60 CEFs  1409 , all of the NG60 headers and all of the data fields in the aggregate MF SC PPDU  1400 . In other words, a total packet length of the NG60 STF  1407 , the NG60 CEFs  1409 , all of the NG60 headers  1412 ,  1422 ,  1432  and  1442  and all of the data fields  1414 ,  1424 ,  1434  and  1444  is set as the Length field in the legacy header  1405 . 
     According to the third embodiment of the present disclosure, symbols may be inverted in the guard interval following immediately the final SC block of every MF SC PPDU in the aggregate MF SC PPDU  1400 . Inverting symbols can be performed by replacing bit  0  and bit  1  with bit  1  and bit  0 , respectively. Consequently, the receiver can easily determine the boundary between neighboring data fields so that it can decode a data field even if some of NG60 headers preceding the NG60 header corresponding to the data field are lost. 
     The ideas and concepts disclosed in this embodiment can be implemented for formatting and transmission of MF OFDM PPDUs. 
       FIG. 15  is a block diagram illustrating example architecture of a wireless communication apparatus  1500  according to the present disclosure. The wireless communication apparatus  1500  includes a controller  1502 , a Tx processor  1510 , a Rx processor  1520  and a plurality of antennas  1530 . The controller  1502  is includes a PPDU generator  1504 , which is configured to create PPDUs, e.g., MF PPDU or aggregate MF PPDU. The Tx processor  1510  includes a Tx baseband processor  1512  and a Tx RF frontend  1514 . The Rx processor  1520  includes a Rx baseband processor  1522  and a Rx RF frontend  1524 . The Tx baseband processor  1512  is illustrated in  FIG. 7  and the Rx baseband processor  1522  is illustrated in  FIG. 9 . The created PPDUs are transmitted through the antenna  1530  after transmitter processing by the Tx processor  1510 . On the other hand, the controller  1502  is configured to analyze and process PPDUs which are received through the antenna  1530  after receiver processing by the Rx processor  1520 . 
     Summarization of Embodiments 
     A transmission apparatus according to an aspect of the present disclosure includes: a signal generator which, in operation, generates a signal having an aggregate physical layer protocol data unit (aggregate PPDU) that includes a legacy preamble, a legacy header, a non-legacy preamble, a plurality of non-legacy headers, and a plurality of data fields; and a transmitter which, in operation, transmits the generated signal, wherein the legacy preamble, the legacy header and the plurality of non-legacy headers are transmitted using a standard bandwidth, the non-legacy preamble and the plurality of data fields are transmitted using a variable bandwidth that is larger than the standard bandwidth and wherein a plurality of sets of each of the plurality of non-legacy headers and each of the plurality of data fields are transmitted sequentially in a time domain. 
     The non-legacy preamble may include a non-legacy short training field (STF) and a plurality of non-legacy channel estimation fields (CEFs) in this order, and one of the plurality of non-legacy headers is located right before the non-legacy STF and one of the plurality of data fields is located right after of the non-legacy CEFs; each of the plurality of remaining non-legacy headers is located right before each of the plurality of remaining data fields. 
     A single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol, which is transmitted in each of the plurality of non-legacy headers may be pre-pended by a guard interval, and a final SC block transmitted in each of the plurality of non-legacy headers is post-pended by a same guard interval as the pre-pended guard interval. 
     A single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol, per space-time stream, which is transmitted in each of the plurality of data fields is pre-pended by a guard interval, and a final SC block per space-time stream transmitted in each of the plurality of data fields may be post-pended by a same guard interval as the pre-pended guard interval. 
     The non-legacy preamble may include a non-legacy short training field (STF) and a plurality of non-legacy channel estimation fields (CEFs) in this order. The plurality of non-legacy headers may be located before the non-legacy STF; the plurality of data fields are located after the plurality of non-legacy CEFs. 
     The plurality of sets may be located in a decreasing or in an increasing order of a number of space-time streams of each of the plurality of data fields. 
     A single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol, which is transmitted in each of the plurality of non-legacy headers may be pre-pended by a guard interval. The final SC block transmitted in the last non-legacy header may be post-pended by a same guard interval as the pre-pended guard interval. 
     A single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol, per space-time stream, which is transmitted in each of the plurality of data fields may be pre-pended by a guard interval. A final SC block per space-time stream transmitted in each of the plurality of data fields may be post-pended by a same guard interval as the pre-pended guard interval. 
     Symbols in the post-pended guard interval may be inverted. 
     A transmission method according to an aspect of the present disclosure includes: generating a signal having an aggregate physical layer protocol data unit (aggregate PPDU) that includes a legacy preamble, a legacy header, a non-legacy preamble, a plurality of non-legacy headers, and a plurality of data fields; and transmitting the generated signal, wherein the legacy preamble, the legacy header and the plurality of non-legacy headers are transmitted using a standard bandwidth, the non-legacy preamble and the plurality of data fields are transmitted using a variable bandwidth that is larger than the standard bandwidth and wherein a plurality of sets each of the plurality of non-legacy headers and each of the plurality of data fields are transmitted sequentially in a time domain. 
     The non-legacy preamble may include a non-legacy short training field (STF) and a plurality of non-legacy channel estimation fields (CEFs) in this order. One of the plurality of non-legacy headers may be located right before the non-legacy STF and one of the plurality of data fields is located right after of the non-legacy CEFs, each of the plurality of remaining non-legacy headers is located right before each of the plurality of remaining data fields. 
     A single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol, which is transmitted in each of the plurality of non-legacy headers may be pre-pended by a guard interval. A final SC block transmitted in each of the plurality of non-legacy headers may be post-pended by a same guard interval as the pre-pended guard interval. 
     A single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol, per space-time stream, which is transmitted in each of the plurality of data fields may be pre-pended by a guard interval. A final SC block per space-time stream transmitted in each of the plurality of data fields may be post-pended by a same guard interval as the pre-pended guard interval. 
     The non-legacy preamble may include a non-legacy short training field (STF) and a plurality of non-legacy channel estimation fields (CEFs) in this order. The plurality of non-legacy headers may be located before the non-legacy STF; the plurality of data fields are located after the plurality of non-legacy CEFs. 
     The plurality of sets may be located in a decreasing or in an increasing order of a number of space-time streams of each of the plurality of data fields. 
     A single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol, which is transmitted in each of the plurality of non-legacy headers is pre-pended by a guard interval, and the final SC block transmitted in the last non-legacy header may be post-pended by a same guard interval as the pre-pended guard interval. 
     A single carrier (SC) block or an orthogonal frequency division multiplexing (OFDM) symbol, per space-time stream, which is transmitted in each of the plurality of data fields is pre-pended by a guard interval, and a final SC block per space-time stream transmitted in each of the plurality of data fields may be post-pended by a same guard interval as the pre-pended guard interval. 
     Symbols in the post-pended guard interval may be inverted. 
     While the embodiments have been described with reference to the drawings, it is needless to say that the present description is not restricted to these examples. It is obvious that one skilled in the art would be able to reach various modifications and alterations without departing from the scope of the Claims, and that such modifications and alterations belong to the technical scope of the present disclosure as a matter of course. The components in the above-described embodiments may also be optionally combined without departing from the scope of the present disclosure. 
     While the above embodiments have been described exemplifying examples of configuring the disclosure using hardware, the present disclosure may be realized by software in conjunction with hardware. 
     The functional blocks used in the description of the embodiments above may be realized as a large-scale integration (LSI) that is an integrated circuit (IC) having input terminals and output terminals. These may each be independently formed as single chips, or part or all may be included in a single chip. While an LSI has been described, there are different names according to the degree of integration, such as IC, system LSI, super LSI, and ultra LSI. 
     The way in which the integrated circuit is formed is not restricted to LSIs, and may be realized by dedicated circuits or general-purpose processors. A field programmable gate array (FPGA) capable of being programmed after manufacturing the LSI, or a reconfigurable processor of which the connections and settings of circuit cells within the LSI can be reconfigured, may be used. 
     Moreover, in the event of the advent of an integrated circuit technology which would replace LSIs by advance of semiconductor technology or a separate technology derived therefrom, such a technology may be used for integration of the functional blocks, as a matter of course. Application of biotechnology is a possibility. 
     This disclosure can be applied to a method for formatting and transmitting an aggregate PPDU in a wireless communications system.

Metadata:
Filing Date: 20210203
Publication Date: 20220830
Grant Date: 20220830
Priority Date: 20150603
Inventors: HUANG, LEI
SIM, HONG CHENG MICHAEL
SAKAMOTO, TAKENORI
Assignee: APPLE INC
CPC Classifications: [{"code": "H04L1/005", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L1/0045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2603", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/22", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L27/2607", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0057", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2613", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/323", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L27/2607", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0094", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2602", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/323", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0094", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2602", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0057", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2602", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2613", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2607", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0091", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0088", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/22", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L1/0631", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0091", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0088", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2603", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0094", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2626", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L27/2626", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L27/2613", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0041", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L1/0088", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2626", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/323", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L1/0057", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0057", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2626", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L69/22", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L1/0631", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0057", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0088", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0094", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/323", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L27/2607", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0091", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2602", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2613", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W84/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2649", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2613", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/2603", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 57440778