A method in a communication network system of enabling auto-tuning of preamble sequences used during random access procedures when user equipments are accessing the communication network system comprising radio base stations each serving at least one cell and with which said user equipments are communicating on uplink and downlink channels, wherein the method comprises the steps of: - using an initial set of robust random access channel preamble sequences in one cell of a radio base station, wherein the initial set of robust random access channel preamble sequences are derived from a number of root sequences based on one or more of base station type, output power, antenna tilt, antenna height, size of said at least one cell and a maximum number of root sequences available, such as 64 root sequences, thereby allowing start up of said at least one cell; - collecting statistics on random access channel usage and information on identified random access channel preamble sequences potentially conflicting between neighbours of said radio base station, wherein statistics on random access channel usage comprises information on delay of initial set of robust random access channel preamble sequences and/or Doppler estimation; - determining a final set of random access channel preamble sequences based on said collected statistics on random access channel usage and said collected information on identified random access channel preamble sequences potentially conflicting between neighbours of said radio base station, wherein the final set of random access channel preamble sequences are derived from a fewer number of root sequences than the initial set of random access channel preamble sequences are derived from, - replacing said Initial set of random access channel preamble sequences with said final set of random access channel preamble sequences. - using an initial set of robust random access channel preamble sequences in one cell of a radio base station, wherein the initial set of robust random access channel preamble sequences are derived from a number of root sequences based on one or more of base station type, output power, antenna tilt, antenna height, size of said at least one cell and a maximum number of root sequences available, such as 64 root sequences, thereby allowing start up of said at least one cell; - collecting statistics on random access channel usage and information on identified random access channel preamble sequences potentially conflicting between neighbours of said radio base station, wherein statistics on random access channel usage comprises information on delay of initial set of robust random access channel preamble sequences and/or Doppler estimation; - determining a final set of random access channel preamble sequences based on said collected statistics on random access channel usage and said collected information on identified random access channel preamble sequences potentially conflicting between neighbours of said radio base station, wherein the final set of random access channel preamble sequences are derived from a fewer number of root sequences than the initial set of random access channel preamble sequences are derived from, - replacing said Initial set of random access channel preamble sequences with said final set of random access channel preamble sequences.