Spectrum shaping for wireless communications
According to an example aspect of the present invention, there is provided a method, comprising: determining to perform frequency domain spectral shaping with spectrum extension to prepare a wireless transmission comprising an inband and an excess band comprising a first excess band portion and a second excess band portion, determining an excess band size, performing remapping of frequency domain resource elements of the inband on the basis of the excess band size, to fill the first excess band portion, and adding, in accordance with the excess band size, a cyclic extension to the second excess band portion based on at least one frequency domain resource element in the inband after said remapping.
1 . An apparatus comprising:
at least one processor; and
at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:
determine to perform, based on at least one of a radio resource control configuration and a downlink control information message received from an access network node, frequency domain spectral shaping with spectrum extension to prepare a wireless transmission comprising an inband and an excess band, the excess band comprising a first excess band portion and a second excess band portion;
determine an excess band size;
perform remapping of frequency domain resource elements of the inband based on the excess band size to fill the first excess band portion; and
add, in accordance with the excess band size, a cyclic extension to the second excess band portion based on at least one frequency domain resource element in the inband after the remapping; and
generate and transmit, based on the frequency domain spectral shaping with the spectrum extension, the wireless transmission as an uplink transmission from the apparatus to the access network node.
2 . The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, further cause the apparatus to: copy at least one frequency domain resource element remapped to the first excess band portion to an end of the inband next to the second excess band portion.
3 . The apparatus of claim 2 , wherein the first excess band portion is an upper excess band above the inband and the second excess band portion is a lower excess band portion below the inband,
the remapping comprises shifting the frequency domain resource elements of the inband to fill the upper excess band,
the adding of the cyclic extension comprises copying, to the lower excess band, at least one frequency domain resource element in the inband which is next to the upper excess band portion after the shifting.
4 . The apparatus of claim 1 , wherein the first excess band portion and the second excess band portion are of same size and located next to the inband.
5 . The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, further cause the apparatus to add the cyclic extension for at least one of data symbols and demodulation reference signal symbols.
6 . The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, further cause the apparatus to: perform, before adding the cyclic extension, a circular shift within the frequency domain resource elements.
7 . The apparatus of claim 6 , wherein the circular shift is dependent on an applied modulation method.
8 . The apparatus of claim 6 , wherein the instructions, when executed by the at least one processor, further cause the apparatus to: perform the circular shift for data symbols and omit the circular shift for demodulation reference signal symbols.
9 . The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, further cause the apparatus to: perform the remapping and add the cyclic extension after a discrete Fourier transform operation for symbols for transmission and before an inverse fast Fourier transform operation to convert an output of adding the cyclic extension mapped to subcarriers to a time-domain signal.
10 . The apparatus of claim 1 , wherein the apparatus is a user equipment, or is included in the user equipment, the user equipment comprising a New Radio transmitter.
11 . An apparatus comprising:
at least one processor; and
at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:
receive a wireless transmission comprising an inband and an excess band, the excess band comprising a first excess band portion and a second excess band portion;
detect frequency domain spectral shaping with spectrum extension being applied in the wireless transmission;
in response to detecting the frequency domain spectral shaping, perform channel estimation and correction for the wireless transmission based on the inband and the excess band to generate channel corrected subcarriers;
perform, before removing a cyclic extension, a remapping of frequency domain resource elements from the excess band to the inband by generating a sum signal by summing at least one of:
the channel corrected subcarriers from the first excess band portion with associated channel corrected subcarriers in the inband, and
the channel corrected subcarriers from the second excess band portion with associated channel corrected subcarriers in the inband;
remove the cyclic extension in the second excess band portion from the sum signal; and
equalize the sum signal after the removal of the cyclic extension.
12 . The apparatus of claim 11 , wherein the apparatus is an access network node, or the apparatus is included in the access network node, the wireless transmission is an uplink transmission from a user equipment, and the instructions, when executed by the at least one processor, further cause the apparatus to trigger the uplink transmission by a downlink control information message.
13 . A method for an apparatus, comprising:
determining to perform frequency domain spectral shaping with spectrum extension to prepare a wireless transmission comprising an inband and an excess band comprising a first excess band portion and a second excess band portion, wherein the first excess band portion is an upper excess band above the inband and the second excess band portion is a lower excess band portion below the inband;
performing the frequency domain spectral shaping by:
determining an excess band size;
shifting frequency domain resource elements of the inband based on the excess band size, to fill the upper excess band; and
adding a cyclic extension to the lower excess band portion by copying, to the lower excess band portion, a first at least one frequency domain resource element in the inband that is next to the upper excess band after the shifting; and
copying a second at least one frequency domain resource element remapped to the upper excess band to an end of the inband next to the lower excess band portion.
14 . The method of claim 13 , wherein the first excess band portion and the second excess band portion are of same size and located next to the inband.