Patent ID: 7680156

Claim:
A random access data transmission system using OFDMA (orthogonal frequency division multiple access) between a mobile station and a base station, the mobile station comprising: a resource selector for selecting a preamble transmission channel and a code-related transmission resource for transmitting a preamble for a random access to the base station; a preamble transmitter for using the transmission resource selected by the resource selector to generate the preamble and transmitting the preamble to the base station though the preamble transmission channel; a preamble access grant processor for (i) receiving acknowledgment or non-acknowledgment information, which includes a scheduling ID provided by the base station for each preamble, in a preamble access grant from the base station in response to the transmission by the preamble transmitter, and (ii) processing the received information; and a data transmitter for transmitting random access data though a data transmission channel associated with the scheduling ID assigned to the mobile station based on the information processed by the preamble access grant processor; wherein the data transmission channel over which the random access data is transmitted from the mobile station to the base station is different from the preamble transmission channel over which the preamble is transmitted from the mobile station to the base station.