Provided are a base station device and a mobile station device, which can lighten a cell-search processing. The base station device includes a frame constitution unit for forming a frame, in which a pilot symbol multiplied by a base station scrambling code 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 for sending the formed frame. On the receiving side, 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.

Systems and methodologies are described that facilitate efficient cell acquisition in a wireless communication system. In one aspect, a reference signal for use in cell acquisition can be constructed in a bandwidth-agnostic manner such that it contains a common central portion in a predetermined frequency band that is independent of a bandwidth utilized by an associated wireless communication system. The central portion can be constructed as a two-dimensional block in time and frequency that spans a default cell search bandwidth, a predetermined bandwidth specified by synchronization codes or other signals, or another suitable bandwidth. A reference signal can then be constructed form the central portion by tiling or expanding the central portion such that it spans the entire system bandwidth.

Communicating using spread spectrum. A legacy RF signal is intercepted from a legacy radio. spread spectrum processing is performed on the legacy RF signal to create a spread signal. The spread signal is transmitted to a receiver, whereafter the spread signal is de-spread to recover the legacy RF signal.

A user equipment (UE) may be configured to receive a signal in a time slot, wherein the signal includes a first reference signal, a second reference signal and data scrambled using a data scrambling sequence. Further, the first reference signal and the second reference signal are not scrambled using the data scrambling sequence. The second reference signal having a code sequence being a non-zero power of two in length and is time multiplexed with the data. The UE recovers the data of the received signal using the first or second reference signal.

A network device for generating an expanded long training sequence with a minimal peak-to-average ratio. The network device includes a signal generating circuit for generating the expanded long training sequence. The network device also includes an Inverse Fourier Transform for processing the expanded long training sequence from the signal generating circuit and producing an optimal expanded long training sequence with a minimal peak-to-average ratio. The expanded long training sequence and the optimal expanded long training sequence are stored on more than 52 sub-carriers.

The invention concerns a method of resolving a time ambiguity in a receiver based on a received radio signal. The radio signal comprises a first signal component and a second signal component. The first signal component comprises a first code of X.sub.1 code symbols, the first code having a duration of C.sub.1 units of time, wherein each of the code symbols has a duration of St units of time. Likewise, the second signal component comprises a second code of X.sub.2 code symbols, the second code having a duration of C2 units of time, wherein each of the code symbols has a duration of S.sub.2 units of time. Either, the code duration C.sub.1 of the first signal component and the code duration C.sub.2 of the second signal component are chosen such that the start or the end of the first code and the second code have a reference code phase offset of D units of time every 2 N units of time, wherein 2N is equivalent to the least common multiple of C.sub.1 and C.sub.2. Or, the code duration C.sub.1 of the first signal component and the code symbol duration S.sub.2 of the second signal component are chosen such that the start or the end of the first code and the second code symbol have a reference code phase offset of D units of time every 2N units of time, wherein 2N is equivalent to the least common multiple of C.sub.1 and S.sub.2. The method comprises acquiring each of the first and second signal components, and performing code symbol synchronization and/or code synchronization for each of the first code and the second code. The method further comprises estimating a code phase offset between the synchronized first code and the synchronized second code, or a code-symbol phase offset between the synchronized first code and the synchronized second code symbol. Finally, the method comprises resolving the time ambiguity of the receiver within a ±N units of time period based on the time-dependent code phase offset or the time-dependent code-symbol phase offset. The invention further concerns radio signal devices.

Provided are a base station device and a mobile station device, which can lighten a cell-search processing. The base station device includes a frame constitution unit for forming a frame, in which a pilot symbol multiplied by a base station scrambling code 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 for sending the formed frame. On the receiving side, 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.

A wireless device is configured to produce a signal in a time slot, the signal having a first portion and a second portion. Wherein, the first portion being a first in time in the time slot and the second portion being last in time in the time slot. Further, the first portion having data and a multiplexed first pilot and the second portion having a pilot sequence and a cyclic prefix. The wireless device transmits the produced signal in the time slot.

The present invention relates to a method in which a user equipment receives a downlink signal from a base station in a wireless communication system that supports downlink mimo transmission according to one embodiment of the present invention comprises: receiving downlink control information that includes information indicative of the number of layers (n, 1≦n≦8) where one or two enabled code words of the downlink mimo transmission are mapped; on the basis of the downlink control information, receiving downlink data transmitted over the respective n layers and a ue-specific reference signal for each of the n layers; and decoding the downlink data on the basis of the ue-specific reference signals, wherein the information indicative of the number of layers can further include information on a code for identifying the ue-specific reference signals.

Multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) communication is provided which allows high accuracy estimation of frequency offset, high accuracy estimation of a transmission path fluctuation and high accuracy synchronization/signal detection. Pilot symbol mapping is provided for forming pilot carriers by assigning orthogonal sequences to corresponding subcarriers among OFDM signals which are transmitted at the same time from respective antennas in the time domain. Even when pilot symbols are multiplexed among a plurality of channels (antennas), this allows frequency offset/phase noise to be estimated with high accuracy.