subject: Brief Description Of The Drawings About Pdu [print this page] which mainly aims at reducing the error rate in transmitting pdu and enhancing the bandwidth utilization of the WCDMA network by dynamically adjusting the size of the pdu. FIG. 1 is a schematic view of a data transmission system for dynamically adjusting the pdu length according to an embodiment of the present invention. Referring to FIG. 1, in this embodiment, the system at least includes a transmitting terminal 110 and a receiving terminal 120. The transmitting terminal 110 is used to transmit data by dividing the data into a plurality of pdu packets with a predetermined pdu length. The receiving terminal 120 is used to receive the data according to a first data message pdu transmitted from the transmitting terminal 110 after establishing an Acknowledged.
Mode Radio Link Control (AM RLC) connection with the transmitting terminal 110, and calculates a ber or a BER of the first data message pdu, so as to calculate an appropriate length of a second data message pdu, and provide a pdu change request to inform the transmitting terminal 110 to adjust the length of the transmitted pdu, so as to continuously receive the subsequent data. In this embodiment, alternatively, the transmitting terminal 110 calculates an appropriate length of a third data message pdu according to a retransmission rate of the retransmitted first data message pdu or according to the ber or the BER of the first data message pdu, and informs the receiving terminal 120 to receive data with the third data message pdu length through the pdu change request. No matter the transmitting terminal 110 or the receiving terminal 120, a pdu change request is required for informing about the changing of an appropriate pdu for continuously transmitting or receiving data.
Before illustrating the relationship between the transmitting terminal 110 and the receiving terminal 120 of this embodiment, different types of the pdu mentioned in the embodiment of the present invention are defined first. In this embodiment, the pdu at least includes three types: a data message pdu, a data acknowledgement message pdu, and a data message length change requirement pdu.
The data message pdu is the main packet for data transmission. The transmitting terminal 110 divides the data required for being transmitted by an upper layer thereof into packets with the data message pdu, and the data is transmitted to the receiving terminal 120 by the transmitting terminal 110. The data acknowledgement message pdu is a packet for feeding back the receiving state of the data message pdu from the transmitting terminal 110 after the receiving terminal 120 has received the data message pdu from the transmitting terminal 110.
the data message length change requirement pdu 230 (briefly referred to as pdu 230) mainly functions to enable the receiving terminal 120 to inform the transmitting terminal 110 to change the length of the pdu 210. The pdu 230 in this embodiment at least includes a changed pdu length field 232. After calculating an appropriate length of the pdu 210, the receiving terminal 120 records the length information in the changed pdu length field 232, and after the transmitting terminal 110 receives the pdu 230, it can obtain the pdu length through the changed pdu length field 232, so as to transmit the pdu 210 with the new pdu length.
The data message length change requirement pdu is a packet for informing the sending terminal 110 about the changing message when the receiving terminal 120 or the transmitting terminal 110 found that the packet size of the data message pdu needs to be changed, and after receiving the data message length change requirement pdu, the transmitting terminal 110 adjusts the length of the transmitted data message pdu accordingly. The above first data message pdu, the second data message pdu, and the third data message pdu all belong to the scope of the data message pdu, and the pdu change request belongs to the scope of the data message length change requirement pdu, which will not be further described in the subsequent paragraphs any more.
