A method comprising: generating (4B-1), by a transmitter, an orthogonal frequency division multiplexing, OFDM, signal associated with a first subcarrier spacing of a first numerology ( μ ), characterized by , a middle subcarrier frequency of a set of usable resource blocks, RBs, of the first numerology being offset from a carrier frequency by a first offset having a value k 0 , x μ in units of subcarriers, the value of the first offset being defined by k 0 , x μ = N grid , x start , μ + N grid , x size , μ / 2 N sc RB − N grid , x start , μ 0 + N grid , x size , μ 0 / 2 N sc RB 2 μ 0 − μ where: x is a channel direction, either "DL" for downlink or "UL" for uplink, μ 0 is a reference numerology associated with a reference subcarrier spacing, N grid , x start , μ is a value of a second offset from a defined reference point to a start of the set of usable RBs of the first numerology μ , in units of RBs, in the channel direction x , N grid , x size , μ is a number of RBs in the set of usable RBs of the first numerology μ , in the channel direction x , N grid , x start , μ 0 is a value of a third offset from the defined reference point to a start of a set of usable RBs of the reference numerology μ 0 , in units of RBs, in the channel direction x , N grid , x size , μ 0 is a number of RBs in the set of usable RBs of the reference numerology μ 0 , in the channel direction x ; and transmitting (4B-2), by the transmitter, the OFDM signal according to the first subcarrier spacing and the first offset. generating (4B-1), by a transmitter, an orthogonal frequency division multiplexing, OFDM, signal associated with a first subcarrier spacing of a first numerology ( μ ), characterized by , a middle subcarrier frequency of a set of usable resource blocks, RBs, of the first numerology being offset from a carrier frequency by a first offset having a value k 0 , x μ in units of subcarriers, the value of the first offset being defined by k 0 , x μ = N grid , x start , μ + N grid , x size , μ / 2 N sc RB − N grid , x start , μ 0 + N grid , x size , μ 0 / 2 N sc RB 2 μ 0 − μ where: x is a channel direction, either "DL" for downlink or "UL" for uplink, μ 0 is a reference numerology associated with a reference subcarrier spacing, N grid , x start , μ is a value of a second offset from a defined reference point to a start of the set of usable RBs of the first numerology μ , in units of RBs, in the channel direction x , N grid , x size , μ is a number of RBs in the set of usable RBs of the first numerology μ , in the channel direction x , N grid , x start , μ 0 is a value of a third offset from the defined reference point to a start of a set of usable RBs of the reference numerology μ 0 , in units of RBs, in the channel direction x , N grid , x size , μ 0 is a number of RBs in the set of usable RBs of the reference numerology μ 0 , in the channel direction x ; and x is a channel direction, either "DL" for downlink or "UL" for uplink, μ 0 is a reference numerology associated with a reference subcarrier spacing, N grid , x start , μ is a value of a second offset from a defined reference point to a start of the set of usable RBs of the first numerology μ , in units of RBs, in the channel direction x , N grid , x size , μ is a number of RBs in the set of usable RBs of the first numerology μ , in the channel direction x , N grid , x start , μ 0 is a value of a third offset from the defined reference point to a start of a set of usable RBs of the reference numerology μ 0 , in units of RBs, in the channel direction x , N grid , x size , μ 0 is a number of RBs in the set of usable RBs of the reference numerology μ 0 , in the channel direction x ; and transmitting (4B-2), by the transmitter, the OFDM signal according to the first subcarrier spacing and the first offset. <EOS>