Patent ID: 6594248
Filing Date: 2003-07-15
Classification: H04B,H04W

Abstract:
A data transmission method used in a CDMA-type radio system comprising at least one base station and a plurality of terminal equipments that exchange data at least in a packet switched mode, a terminal equipment transmitting to the base station on a random access channel a random access signal comprising at least a preamble and a data part multiplied by a spreading code, whereina predetermined set of spreading codes and signature sequences are stored at the terminal equipment or the terminal equipment generates such a predetermined set of spreading codes and signature sequences, and each signature sequence determines one spreading code; the terminal equipment selects one signature sequence by a random process from the set of signature sequences and adds the selected signature sequence to the preamble of the random access signal; the terminal equipment uses the spreading code corresponding to the selected signature sequence in the data part of the random access signal; interference cancellation is performed at the base station according to the signature sequence of the preamble of the received random access signal, such that at least the interference caused by the received data part is eliminated from at least one other received signal in order to increase data transmission capacity and to improve detection, and wherein when the base station performs interference cancellation on the random access signals, it indicates on the broadcast control channel a total interference level of the received signals that is higher than the real interference level so that the terminal equipment would increase the power of the random access signal it transmits according to the interference cancellation capacity of the base station.