Patent ID: 8194619
Filing Date: 2012-06-05
Classification: H04W

Abstract:
1. A ranging method of an access terminal that requests a ranging process from an access point through a wireless network and performs the ranging process according to a corresponding response of the access point, the ranging method comprising: a) receiving and analyzing a UL-MAP provided from the access point, and extracting information on an uplink resource allocated to the access terminal; b) selecting an uplink sub-channel number and a symbol number from the UL-MAP when a ranging event is generated; c) requesting a ranging process by transmitting a Code Division Multiple Access (CDMA) code including the symbol number to the access point through the selected sub-channel number, storing the sub-channel number, the symbol number, and the CDMA code as ranging parameters, and further storing a frame number of a current frame in which the CDMA code is transmitted; d) receiving a ranging response message broadcasted from the access point; e) extracting a CDMA code, a sub-channel number, a symbol number, and a frame number from the received ranging response message, comparing the extracted result with the stored ranging parameters including the stored frame number, and controlling transmission power, timing, and frequency offset on the basis of the extracted result when the extracted result and the stored ranging parameters are the same; f) extracting a CDMA code, a sub-channel number, and a symbol number from the received ranging response message, comparing the extracted result with the stored ranging parameters, and discarding the received ranging response message when the extracted result and the stored ranging parameters are not the same; and g) terminating the ranging response message receipt operation and performing a) through f) when a ranging response message of which ranging parameters are identical to the stored ranging parameter is not received after a predetermined time, wherein the terminating of the ranging response message receipt operation comprises stopping analyzing of a predetermined portion of a DL_MAP while receiving and processing the DL_MAP.