1. Field of the Invention
The present invention relates to data packet processing and more particularly, to a packet processing method for use in a wireless packet transmission.
2. Description of the Related Art
In wireless digital communications, a corresponding error detection and control measure is employed to assure high speed and high reliability data transmission. This measure includes an error detection and correction method in which a check code is transmitted with the data to the receiver, and the receiver checks the correctness of the received data. If each data does not occupy much communication bit space and short packet data format is employed to mach the error check for transmission processing, the digital communication can have high speed and high reliability characteristics. However, under the fast development step of information technology, if the data occupies a long bit space, shortening the signal transmission processing time in order to achieve signal transmission rapidly in time may narrow the signal waveform, relatively increasing the chance of bit transmission error. Any interference of the transmission medium or external noises during the transmission may relatively increase the chance of error.
For example, in all error check processing methods, a CRC (Cyclic Redundancy Check) is an easy way to analyze mathematically, and good at detecting common errors caused by noise in transmission channels. A CRC is method of checking for errors in data that has been transmitted on a communications link. The dividend polynomial is initially preset to 0, and the 1s and 0s of the data stream become the coefficients of the dividend polynomial. The division uses subtraction modulo 2 (no carries), and the remainder is transmitted as the error check field. The receiving station compares the transmitted remainder with its own computed remainder, and an equal condition indicates that no error has occurred. The polynomial value depends on the protocol and code set being used. In other words, the higher the order of the polynomial value is, the lower the chance of error in the CRC will be. However, because the transmission of a long data requires a higher order of CRC to avoid detection error, the transmission signal waveform needs to carry a long data, lowering the data transmission speed. Unless a circuit processing device of high transmitting power is used to improve the transmission speed and to compensate the increasing of bit error rate due to lowering of the bit width, the effective energy transmission distance of the wireless communication will be limited, and the chance of packet collision will increase, resulting in a detection error and data error.