A method performed by a wireless device, the method comprising: receiving a first portion of a PHY Protocol Data Unit, PPDU, the first portion including a Legacy Signal, L-SIG, field; decoding the L-SIG field; determining a format of the PPDU using the first portion; and in response to determining that the format of the PPDU is a High Efficiency, HE, format: receiving and decoding an HE Signal A, HE-SIG-A, field (610, 910) included in a second portion of the PPDU, determining, using a Doppler field of the HE-SIG-A field, whether the PPDU includes mid-ambles, and in response to determining that the PPDU includes mid-ambles: determining, according to the format of the PPDU and using first information determined using the HE-SIG-A field and a Length field value L_LENGTH determined using the L-SIG field, a number of mid-ambles N MA indicating a total number of mid-ambles included in a data field of the PPDU; determining, using the number of the mid-ambles N MA, a number of data symbols N SYM indicating a total number of data symbols included in the data field of the PPDU; and receiving, using the number of mid-ambles N MA and the number of data symbols N SYM, the data field of the PPDU; wherein the first information includes a Packet Extension, PE, Disambiguity bit value b PE-Disambiguity, a data symbol duration T SYM, a mid-amble periodicity M, a mid-amble duration T MA. and a preamble duration T PA,; wherein the number of mid-ambles N MA is determined according to: N MA = ⌊ L _ LENGTH + m + 3 3 × 4 − T PA − T SYM 1 + β + b PE − Disambiguity T MA + M ⋅ T SYM ⌋ or according to: N MA = ⌈ L _ LENGTH + m + 3 3 × 4 − T PA − T SYM 1 + β + b PE − Disambiguity + M T MA + M ⋅ T SYM ⌉, wherein β is an integer number greater than or equal to zero, and m is 1 when the format of the PPDU is an HE Multi-User PPDU or HE Extended Range Single User PPDU format and m is 2 otherwise. receiving a first portion of a PHY Protocol Data Unit, PPDU, the first portion including a Legacy Signal, L-SIG, field; decoding the L-SIG field; determining a format of the PPDU using the first portion; and in response to determining that the format of the PPDU is a High Efficiency, HE, format: receiving and decoding an HE Signal A, HE-SIG-A, field (610, 910) included in a second portion of the PPDU, determining, using a Doppler field of the HE-SIG-A field, whether the PPDU includes mid-ambles, and in response to determining that the PPDU includes mid-ambles: determining, according to the format of the PPDU and using first information determined using the HE-SIG-A field and a Length field value L_LENGTH determined using the L-SIG field, a number of mid-ambles N MA indicating a total number of mid-ambles included in a data field of the PPDU; determining, using the number of the mid-ambles N MA, a number of data symbols N SYM indicating a total number of data symbols included in the data field of the PPDU; and receiving, using the number of mid-ambles N MA and the number of data symbols N SYM, the data field of the PPDU; receiving and decoding an HE Signal A, HE-SIG-A, field (610, 910) included in a second portion of the PPDU, determining, using a Doppler field of the HE-SIG-A field, whether the PPDU includes mid-ambles, and in response to determining that the PPDU includes mid-ambles: determining, according to the format of the PPDU and using first information determined using the HE-SIG-A field and a Length field value L_LENGTH determined using the L-SIG field, a number of mid-ambles N MA indicating a total number of mid-ambles included in a data field of the PPDU; determining, using the number of the mid-ambles N MA, a number of data symbols N SYM indicating a total number of data symbols included in the data field of the PPDU; and receiving, using the number of mid-ambles N MA and the number of data symbols N SYM, the data field of the PPDU; determining, according to the format of the PPDU and using first information determined using the HE-SIG-A field and a Length field value L_LENGTH determined using the L-SIG field, a number of mid-ambles N MA indicating a total number of mid-ambles included in a data field of the PPDU; determining, using the number of the mid-ambles N MA, a number of data symbols N SYM indicating a total number of data symbols included in the data field of the PPDU; and receiving, using the number of mid-ambles N MA and the number of data symbols N SYM, the data field of the PPDU; wherein the first information includes a Packet Extension, PE, Disambiguity bit value b PE-Disambiguity, a data symbol duration T SYM, a mid-amble periodicity M, a mid-amble duration T MA. and a preamble duration T PA,; wherein the number of mid-ambles N MA is determined according to: N MA = ⌊ L _ LENGTH + m + 3 3 × 4 − T PA − T SYM 1 + β + b PE − Disambiguity T MA + M ⋅ T SYM ⌋ or according to: N MA = ⌈ L _ LENGTH + m + 3 3 × 4 − T PA − T SYM 1 + β + b PE − Disambiguity + M T MA + M ⋅ T SYM ⌉, wherein β is an integer number greater than or equal to zero, and m is 1 when the format of the PPDU is an HE Multi-User PPDU or HE Extended Range Single User PPDU format and m is 2 otherwise.