Patent ID: 8199778

Claim:
A random access channel transmission method, comprising: selecting a preamble pattern from among a plurality of known preamble patterns in a user terminal; and transmitting that preamble pattern to a base station from the user terminal, wherein a user terminal that exists in an area close to the base station repeats a first preamble pattern M number of times and transmits the preamble generated by the repetition, and a user terminal that exists in an area far from the base station repeats a second preamble pattern N (M<N) number of times and transmits the preamble generated by the repetition, wherein the base station sets said known preamble patterns for each area using CAZAC sequences, and a CAZAC sequence is used as a plurality of preamble patterns by changing the cyclic shift interval of the CAZAC sequence by each of a plurality of user terminals, and wherein the cyclic shift interval of a CAZAC sequence which is used in an area where the number of repetitions is small, is made to be narrow, and the cyclic shift interval of a CAZAC sequence which is used in an area where the number of repetitions is large, is made to be wide.