The present disclosure relates to a client device and a network access node for transmitting and receiving a random access preamble which comprises a division of a set of resource blocks available for transmission of the random access preamble into at least two subsets of resource blocks, wherein each resource block in the set of resource blocks comprises a plurality of subcarriers, a first selection of resource blocks within the first subset of resource blocks and a second selection of resource blocks within the second subset of resource blocks, wherein the first selection of resource blocks is different to the second selection of resource blocks, and a mapping of a modulation sequence of the random access preamble onto at least one subcarrier in each selected resource block. Thereby, lower side-lobes of the auto-correlation function is achieved. Furthermore, the present disclosure also relates to corresponding methods and a computer program.