A method for selecting a frequency block for radio communications, the method comprising in a first node of a wireless network: determining (400, 600, 700) a first value representing a lowest noise level of a radio channel experienced at a node in a first frequency block, wherein the node is the first node or a second node; calculating (400, 604, 704) a first metric representing a ratio between a first desired signal strength and the first value, wherein the first desired signal strength represents a desired signal strength between the first node and the second node in the first frequency block, and wherein the first metric represents the highest potential signal-to-noise ratio in the first frequency block; determining (402, 600, 700) a second value representing a lowest noise level of a radio channel at the node in a second frequency block; calculating (402, 604, 704) a second metric representing a ratio between a second desired signal strength and the second value, wherein the second desired signal strength represents a desired signal strength between the first node and the second node in the second frequency block, and wherein the second metric represents the highest potential signal-to-noise ratio in the second frequency block; selecting, on the basis of at least the first and second metric and amongst a set of frequency blocks comprising at least the first and second frequency block, a frequency block for transmission of a message between the first node and the second node; indicating (406, 606) a sub-band of the selected frequency block for the message; and causing (408, 608, 706) transmission of the message on the indicated sub-band of the selected frequency block. determining (400, 600, 700) a first value representing a lowest noise level of a radio channel experienced at a node in a first frequency block, wherein the node is the first node or a second node; calculating (400, 604, 704) a first metric representing a ratio between a first desired signal strength and the first value, wherein the first desired signal strength represents a desired signal strength between the first node and the second node in the first frequency block, and wherein the first metric represents the highest potential signal-to-noise ratio in the first frequency block; determining (402, 600, 700) a second value representing a lowest noise level of a radio channel at the node in a second frequency block; calculating (402, 604, 704) a second metric representing a ratio between a second desired signal strength and the second value, wherein the second desired signal strength represents a desired signal strength between the first node and the second node in the second frequency block, and wherein the second metric represents the highest potential signal-to-noise ratio in the second frequency block; selecting, on the basis of at least the first and second metric and amongst a set of frequency blocks comprising at least the first and second frequency block, a frequency block for transmission of a message between the first node and the second node; indicating (406, 606) a sub-band of the selected frequency block for the message; and causing (408, 608, 706) transmission of the message on the indicated sub-band of the selected frequency block.