In a broadband wireless access system according to the related art, a channel quality indicator (hereinafter, referred to as “CQI”) is transmitted through a fast feedback channel, a bandwidth (BW) request signal is transmitted through a ranging channel, and acknowledgement/negative acknowledgement (hereinafter, referred to as “ACK/NACK”) signals are transmitted through ACK/NACK channels.
In the aforementioned broadband wireless access system according to the related art, in which the CQI and the bandwidth request signal are respectively transmitted through separate channels, if a mobile station (MS) requests a base station (BS) to provide uplink resources, since the ranging channel is contention-based and a plurality of mobile stations can simultaneously use the same code, it is difficult to success the bandwidth request only one time. Also, for request of uplink resources, CDMA code of 144 bits should be transmitted to the base station, and at least two slots (or six slots: in case of transmission of three CDMA codes) should be used. Accordingly, if transmission is performed several times as the bandwidth request fails to be successfully performed only one time, a problem occurs in that a waste of the power and frequency resources may be caused in the mobile station.
Meanwhile, in order to solve the aforementioned problem, a method for transmitting specific BW request information to a corresponding position without transmitting channel status information to a CQI channel (hereinafter, referred to as “CQICH”) has been suggested. However, this method still has a problem in that channel status information is not transmitted during bandwidth request.
Furthermore, if CQI information and ACK/NACK information are respectively transmitted through separate channels in the same manner as a mobile communication system according to the related art, since ACK/NACK information of the mobile station is prior to CQI information, the mobile station should transmit ACK/NACK information only to the base station, or should additionally allocate corresponding CQICH to transmit CQI information and ACK/NACK information. Also, if an ACKCH region is allocated to a region such as a fast feedback channel, a problem occurs in that a waste of radio resources is caused as a fast feedback channel should newly be allocated.
If each of control information is transmitted through a separate control channel as above, a waste of the transmission power and radio resources may be caused in the mobile station. In this respect, a technique of transmitting additional control information to a control channel is required.