What Are The Benefits Of Internet Control Message Protocol?

similarly, this second data message pdu is also the above pdu 210. The bandwidth utilization may be calculated and obtained through the following equation: Bandwidth utilization=(1-ber)pdu length(pdu length-pdu header)/pdu length, which is not limited in this embodiment. The receiving terminal 120 calculates bandwidth utilizations of the available pdu types of pdu lengths that are configured in the RRC message when the connection is established, selects a pdu length corresponding to the maximum bandwidth utilization as the length of the changed second data message pdu. After the receiving terminal 120 determines the length of the second data message pdu, it informs the transmitting terminal 110 about the length of the second data message pdu through the pdu change request.

Finally, in Step (D), the transmitting terminal 110 transmits data to the receiving terminal 120 by utilizing the second data message pdu mentioned in the pdu change request, and the transmitting terminal 110 generates the second data message pdu according to the record of the pdu change request, and sets the data length reset bit in the second data message pdu as 1 when transmitting the second data message pdu for the first time, so as to inform the receiving terminal 120 to receive the subsequent pdu with the updated pdu length. After receiving the second data message pdu, the receiving terminal 120 changes the used pdu length.

It should be noted that, besides the circumstance that the transmitting terminal 110 changes to transmit data to the receiving terminal 120 with the second data message pdu according to the pdu change request transmitted from the receiving terminal 120, the transmitting terminal 110 may automatically generate an appropriate pdu length of a third data message To sum up, the data transmission system and method for dynamically adjusting the pdu length in the present invention, applicable for dynamically adjusting and achieving the most appropriate pdu length according to the ber or the BER of data transmission, has the following advantages. pdu according to the ber or the BER fed back from the receiving terminal 120. The third data message pdu, similar to the second data message pdu, is a kind of the data message pdu. The transmitting terminal 110 uses the third data message pdu to transmit data. The steps for the transmitting terminal 110 to transmit data with the third data message pdu are similar to those for transmitting data with the second data message pdu, which thus will not be further described herein any more.

To make the above data transmission method be more clearly understood, a timing chart is taken as an example for illustration. FIG. 4 is a timing chart of the data transmission system and method according to this embodiment. Referring to FIG. 4, first, a connection is established between the transmitting terminal 110 and the receiving terminal 120. Next, the transmitting terminal 110 sequentially transmits the first data message pdus with the sequence numbers (SN) as 0, 1, 2 to the receiving terminal 120, wherein the used pdu length is 18, and the initial value of the data length reset bit is 0. After receiving the first data message pdus, the receiving terminal 120 performs the check sum operation, and feeds back the checking result to the transmitting terminal 110 with the data acknowledgement message pdu. In this example, the receiving terminal 120 found that the first data message pdu with the sequence number of 2 needs to be retransmitted, and at this time, the receiving terminal 120 calculates an appropriate pdu length.

After the calculation, the receiving terminal 120 informs the transmitting terminal 110, with the data message length change requirement pdu, to transmit data with the second data message pdu having the pdu length of 25. After receiving the data message length change requirement pdu, if the transmitting terminal 110 cannot get read to transmit data with the second data message pdu in real time, it transmits the data with the original first data message pdu. If the transmitting terminal 110 got ready to transmit data with the second data message pdu, it transmits data with the second data message pdu, and at this time, the transmitting terminal 110 sets the data length reset bit as 1 to inform the receiving terminal 120 to change the predetermined pdu length for receiving.

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