Traffic Control Method of Random Access Channel in Asynchronous Wireless Communication System

摘要

PURPOSE: A traffic control method of a random access channel in an asynchronous mobile communication system is provided to constantly use a random access channel at a required level of power and minimize an influence to a different channel by using the random access channel as a frame structure, discriminating signatures by request transfer rate spreading factor of several groups and rendering a base station to control a channel use on the basis of information on the number of preambles transmitted to a previous frame. CONSTITUTION: Each radio mobile terminal which has generated a packet to be transmitted obtains a channel through a preamble transmission. In order to reduce a packet collision, the radio mobile terminal selects one of signatures, that is, 16 orthogonal code, selects one of 8 slots existing in the generated frame and transmits a preamble. A base station receives the preamble properly transmitted without a collision or other error, and if a channel use of the used signature is available, the base station transmits a positive ACK signal through the obtained instruction channel to transmit the signature used by the mobile terminal to a down channel. If the channel of the signature being used is not available due to a blocking, the base station transmits a negative ACK signal to transmit a signal obtained by multiplying the used signature by -1. If the base station receives a positive ACK signal from the obtained instruction channel, the base station transmits a data packet by using an orthogonal code for spreading factor corresponding to the used signature. By operating the random access channel, a collision frequently taking place in the channel due to the slotted ALOHA characteristics can be minimized.