Abstract: A base station apparatus that transmits frames in accordance with a communication format, and a mobile station apparatus that uses the frames to determine the communication format of the base station apparatus, and then performs an adaptive cell search in accordance with the determined communication format. The base station apparatus (100) comprises a plurality of antennas; a transmitting part (150) that transmits frames via the antennas; and a frame forming part (130) that forms, in accordance with the number of antennas to be used for the transmission, frames in which different synchronization sequences (SCH sequences) are arranged.

Abstract: Provided are a base station device and a mobile station device, which can lighten a cell-search processing. The base station device (100) includes a frame constitution unit (130) for forming a frame, in which a pilot symbol multiplied by a base station scrambling code assigned to that device and a plurality of sequences contained in the corresponding sequence set is arranged in at least the head or tail, and a radio transmission unit (155) for sending the formed frame. On the receiving side of the frame, the frame timing can be detected from the position of a pilot symbol contained in that frame. Since the base station scrambling code and the sequence set containing the sequences are made to correspond to each other, candidates can be narrowed to at most the base station scrambling codes of the number of the combinations of the sequences contained in the sequence set, by detecting the sequences multiplied by the pilot symbol, so that the cell search processing can be lightened.

Abstract: There is provided a multi-carrier communication method capable of preventing lowering of a throughput of another mobile device accompanying allocation of a sub-carrier for a new mobile station device. This multi-carrier communication method can acquire reception quality information for one of the sub-carriers already allocated in an MS (150a) from a BS (100a) and for one of the sub-carriers which can be allocated in the MS (150a) from the BS (100b). According to the reception quality information, a release sub-carrier is selected from the sub-carriers already allocated and a new-allocation sub-carrier is selected from the sub-carriers which can be allocated. The new-allocation sub-carrier has a frequency different from the already-allocated sub-carriers excluding the release sub-carrier. The BS (100a) is instructed to release the selected release sub-carrier and the BS (100b) is instructed to allocate the selected new-allocation sub-carrier in the MS (150a).

Abstract: A base station apparatus capable of effectively distributing resources of a wireless communication system, enhancing the throughput and increasing the number of users accommodated in the communication system. This apparatus increases or reduces, in accordance with the traffic of the communication system, the repetition number of transport data addressed to a mobile station being under a soft handover. For example, when the resource usage rates of BS1, BS2 and BS3 are low, intermediate and high, respectively, the repetition number for MS1 being under a soft handover is set, in accordance with the resource usage rates, for example, to four for BS1, to two for BS2 and to one for BS3.

Abstract: There is provided a mobile station device capable of reducing processing of cell search. In this device, an FFT timing detection unit (603) detects a symbol timing and a frame timing detection unit (606) detects a frame timing by using the frame timing detection symbol. After a frame timing is detected, a code group detection unit (608) detects a code group and a scrambling code identification unit (610) identifies a scrambling code. That is, the frame timing detection process is separated from the code group detection process and after detecting the frame timing, a symbol timing multiplied by the code group sequence is identified so that the code group is detected only at the symbol timing.

Abstract: A mobile station device which can correctly search for another cell quickly in a communication system using the OFCDM method. A blank subcarrier correlation calculating section (502) calculates the correlation between the blank subcarriers of the CPICH symbols adjacent to the cell signal of this mobile station device. A correlation-between-adjacent-symbols calculating section (503) calculates correlation between adjacent symbols in the frequency direction. A correlation value comparing section (505) compares the correlation values inputted from the correlation-between-adjacent-symbols calculating section (503) and detects the boundary between adjacent symbols having the maximum correlation value as a frame timing of the another cell.