Bandwidth extension of harmonic audio signal

A method performed by a transform audio decoder for supporting bandwidth extension, BWE, of a harmonic audio signal, the method comprising:

• receiving, through a communication circuit, the harmonic audio signal and a plurality of gain values associated with a frequency band b and a number of adjacent frequency bands of band b;
• determining, by the transform audio decoder, whether a reconstructed corresponding frequency band b′ of a bandwidth extended frequency region of the harmonic audio signal comprises at least one spectral peak, and
• when the reconstructed frequency band b′ comprises at least one spectral peak:
• setting, by the transform audio decoder, a gain value associated with the reconstructed frequency band b′ to a first value based on the received plurality of gain values;
• wherein the first value is a weighted sum of the received plurality of gain values, and
• when the reconstructed frequency band b′ does not comprise any spectral peak:
• setting, by the transform audio decoder, the gain value associated with the reconstructed frequency band b′ to a second value based on the received plurality of gain values, wherein the second value is lower than or equal to the first value,
• thus enabling bringing gain values into agreement with peak positions in the bandwidth extended frequency region of the harmonic audio signal to generate, by the transform audio decoder, a bandwidth-extended audio signal, and
• transmitting, through the communication circuit, the bandwidth-extended audio signal.