A transmission apparatus comprising: a signal processing circuit that is configured to generate an aggregate physical layer convergence protocol data unit, APPDU (2000; 2500), including a first PPDU (2001; 2501) and second PPDUs (2002, 2003; 2502, 2503), the first PPDU (2001; 2501) comprising a first portion and a second portion, wherein the first portion of the first PPDU (2001, 2501) includes: - a set of a legacy STF (2004; 2504), a legacy CEF (2005; 2505), a legacy header field (2006; 2506) and a non-legacy header field (2007; 2507), which is transmitted using a standard channel bandwidth, and - an (N - 1) count of duplicates of the set of the legacy STF (2004; 2504), the legacy CEF (2005; 2505), the legacy header field (2006; 2506) and the non-legacy header field (2007; 2507) in a frequency axis direction, wherein each of the (N-1) duplicates is transmitted using the standard channel bandwidth, the second portion of the first PPDU (2001; 2501) includes a non-legacy STF (2008; 2508), a non-legacy CEF (2009; 2509) and a data field (2010; 2510), which is transmitted using a variable channel bandwidth that is N times the standard channel bandwidth, wherein N is an integer of 2 or greater, each of the second PPDUs (2002, 2003; 2502, 2503) includes one or more non-legacy header fields (2011, 2013; 2511, 2513) and one or more data fields (2012, 2014; 2512, 2514), which are transmitted using the variable channel bandwidth, and a plurality of guard intervals are added to each of the first portion of the first PPDU (2001; 2501), the second portion of the first PPDU (2001; 2501) and the second PPDUs (2002, 2003; 2502, 2503); and a wireless unit that is configured to transmit the APPDU (2000, 2500) wherein, in a case where the first PPDU and the second PPDUs (2002, 2003) are transmitted by a single carrier, the one or more non-legacy header fields (2011, 2013) of the second PPDUs (2002, 2003) include one or more single carrier blocks (2019, 2020); and wherein (N - 1) count of non-legacy headers is duplicated in a time axis direction, for each of the single carrier blocks (2019, 2020) in the one or more non-legacy header fields (2011, 2013) of the second PPDUs (2002, 2003). a signal processing circuit that is configured to generate an aggregate physical layer convergence protocol data unit, APPDU (2000; 2500), including a first PPDU (2001; 2501) and second PPDUs (2002, 2003; 2502, 2503), the first PPDU (2001; 2501) comprising a first portion and a second portion, wherein the first portion of the first PPDU (2001, 2501) includes: - a set of a legacy STF (2004; 2504), a legacy CEF (2005; 2505), a legacy header field (2006; 2506) and a non-legacy header field (2007; 2507), which is transmitted using a standard channel bandwidth, and - an (N - 1) count of duplicates of the set of the legacy STF (2004; 2504), the legacy CEF (2005; 2505), the legacy header field (2006; 2506) and the non-legacy header field (2007; 2507) in a frequency axis direction, wherein each of the (N-1) duplicates is transmitted using the standard channel bandwidth, - a set of a legacy STF (2004; 2504), a legacy CEF (2005; 2505), a legacy header field (2006; 2506) and a non-legacy header field (2007; 2507), which is transmitted using a standard channel bandwidth, and - an (N - 1) count of duplicates of the set of the legacy STF (2004; 2504), the legacy CEF (2005; 2505), the legacy header field (2006; 2506) and the non-legacy header field (2007; 2507) in a frequency axis direction, wherein each of the (N-1) duplicates is transmitted using the standard channel bandwidth, the second portion of the first PPDU (2001; 2501) includes a non-legacy STF (2008; 2508), a non-legacy CEF (2009; 2509) and a data field (2010; 2510), which is transmitted using a variable channel bandwidth that is N times the standard channel bandwidth, wherein N is an integer of 2 or greater, each of the second PPDUs (2002, 2003; 2502, 2503) includes one or more non-legacy header fields (2011, 2013; 2511, 2513) and one or more data fields (2012, 2014; 2512, 2514), which are transmitted using the variable channel bandwidth, and a plurality of guard intervals are added to each of the first portion of the first PPDU (2001; 2501), the second portion of the first PPDU (2001; 2501) and the second PPDUs (2002, 2003; 2502, 2503); and a wireless unit that is configured to transmit the APPDU (2000, 2500) wherein, in a case where the first PPDU and the second PPDUs (2002, 2003) are transmitted by a single carrier, the one or more non-legacy header fields (2011, 2013) of the second PPDUs (2002, 2003) include one or more single carrier blocks (2019, 2020); and wherein (N - 1) count of non-legacy headers is duplicated in a time axis direction, for each of the single carrier blocks (2019, 2020) in the one or more non-legacy header fields (2011, 2013) of the second PPDUs (2002, 2003).