Patent ID: 7724726

Claim:
A data transmission method for dynamically adjusting a protocol data unit (PDU) length, applicable to a Wideband Code Division Multiple Access (WCDMA) network at least comprising a transmitting terminal and a receiving terminal, the data transmission method comprising: (A) establishing a connection between the transmitting terminal and the receiving terminal; (B) the transmitting terminal transmitting data to the receiving terminal with a first data message PDU; (C) the receiving terminal or the transmitting terminal providing a PDU change request, further comprising: the receiving terminal or the transmitting terminal calculating a bit error rate (ber) or a Block Error Rate (BER) of the received first data message PDU, and informing the transmitting terminal or the receiving terminal about the ber or the BER with the PDU chance request or a response message; and the receiving terminal determining whether to change the used PDU length or not according to the ber or the BER, and calculating a PDU length that achieves a maximum bandwidth utilization as the length of the second data message PDU, wherein the receiving terminal informs the transmitting terminal about the length of the second data message PDU through the PDU change request; and (D) the receiving terminal using the PDU change request to recalculate a second data message PDU, or the transmitting terminal using the PDU change request to recalculate a third data message PDU to continuously transmit data; wherein the method for calculating the PDU length that achieves the maximum bandwidth utilization comprises calculating bandwidth utilizations of the PDU lengths in the RRC message, and then selecting a PDU length corresponding to the maximum value as the PDU length of the maximum bandwidth utilization, wherein the bandwidth utilization is calculated through the following equation: Bandwidth utilization=(1−ber) PDU length ×(PDU length−PDU header)/PDU length, wherein the PDU header is the header of the PDU.