Abstract: A reception method and apparatus for use in a multi-cell orthogonal frequency division multiple access (OFDMA) wireless system. In a unicast receive mode during a first receive time period, a first group of orthogonal frequency division multiplexing (OFDM) symbols is received by a mobile device from multiple of a plurality of antennas at a serving base station. In a single-frequency-network (SFN) receive mode during a second receive time period, a second group of OFDM symbols is received by the mobile device from one of a plurality of antennas at the serving base station. The transition between the first receive time period and the second receive time period occurs during a cyclic prefix or a cyclic postfix between OFDM symbols, and the plurality of antennas produce a first beam pattern during the unicast receive mode and a second beam pattern during the SFN receive mode.

Abstract: A mobile station operable to perform cell synchronization is described. The mobile station can process one or more synchronization signals received in a downlink from one or more base stations providing coverage in one or more cells. The mobile station can process the one or more synchronization signals received from the one or more base stations to synchronize the mobile station with the one or more base stations. The mobile station can adjust signals for communication from the mobile station in accordance with the cell synchronization performed at the mobile station.

Abstract: An arrangement is disclosed where in a multi-carrier communication system, the modulation scheme, coding attributes, training pilots, and signal power may be adjusted to adapt to channel conditions in order to maximize the overall system capacity and spectral efficiency without wasting radio resources or compromising error probability performance, etc.

Abstract: In a cellular wireless network, methods and apparatus are disclosed for a signal broadcasting scheme that can be individually augmented for users with poor reception. The network employs a first downlink channel for broadcasting data to all mobile stations, a second downlink channel for sending signals to a specific mobile station in a cell, and an uplink channel for feeding back information to the base station. To achieve a certain user reception quality, the system adjusts its broadcasting parameters based on the statistical analysis of the feedback data. If some users still require better reception, the system individually augments their broadcast signals via the second downlink channels. Methods and apparatus are also disclosed for synchronization of data distribution by base stations, which, in part, allows the receivers to combine the receiving signals and improve their reception quality.

Abstract: A method and system for minimizing the control overhead in a multi-carrier wireless communication network that utilizes a time-frequency resource is disclosed. In some embodiments, one or more zones in the time-frequency resource are designated for particular applications, such as a zone dedicated for voice-over-IP (VoIP) applications. By grouping applications of a similar type together within a zone, a reduction in the number of bits necessary for mapping a packet stream to a portion of the time-frequency resource can be achieved. In some embodiments, modular coding schemes associated with the packet streams may be selected that further reduce the amount of necessary control information. In some embodiments, packets may be classified for transmission in accordance with application type, QoS parameters, and other properties. In some embodiments, improved control messages may be constructed to facilitate the control process and minimize associated overhead.

Abstract: A method and apparatus for content multicasting and broadcasting and data unicasting in a broadband multicarrier wireless communication system. A base station is configured to transmit, and a mobile station is configured to receive, a sequence of consecutive frames. The frames comprise two types: frames containing time-frequency resources for content multicasting and broadcasting via a single frequency network, and frames containing time-frequency resources for data unicasting without the use of a single frequency network. The two types of frames are intermixed in accordance with an intermixing configuration pattern. The intermixing configuration pattern is indicated by a bit-map contained in a scheduling signal.

Abstract: Methods and apparatus for subframe configuration and generation in a multi-cell multi-carrier system. A frame for radio transmission in the system consists of multiple subframes, and each subframe consists of multiple Orthogonal Frequency Division Multiplexing (OFDM) symbols. Training symbols, frequency-domain data scrambling, size of Fast-Fourier Transform (FFT), or length of cyclic prefix can be configured differently for each subframe to facilitate different applications, such as unicasting or broadcasting.

Abstract: A multi-carrier cellular wireless network (400) employs base stations (404) that transmit two different groups of pilot subcarriers: (1) cell-specific pilot subcarriers, which are used by a receiver to extract information unique to each individual cell (402), and (2) common pilots subcarriers, which are designed to possess a set of characteristics common to all the base stations (404) of the system. The design criteria and transmission formats of the cell-specific and common pilot subcarriers are specified to enable a receiver to perform different system functions. The methods and processes can be extended to other systems, such as those with multiple antennas in an individual sector and those where some subcarriers bear common network/system information.

Abstract: Methods and systems are disclosed for communicating in a wireless communications system utilizing a plurality of frequency bands for downlink (DL) transmission and a plurality of frequency bands for uplink (UL) transmission. In an embodiment, a mobile device receives a DL signal via a DL frequency band. The DL signal contains DL-UL frequency-band association information. The DL signal is decoded to obtain the DL-UL frequency-band association information which is used to determine a UL frequency band for UL transmission. The mobile device configures its radio-frequency (RF) circuitry to operate in the UL frequency band for UL transmission.

Abstract: In a broadband wireless communication system, a spread spectrum signal is intentionally overlapped with an OFDM signal, in a time domain, a frequency domain, or both. The OFDM signal, which inherently has a high spectral efficiency, is used for carrying broadband data or control information. The spread spectrum signal, which is designed to have a high spread gain for overcoming severe interference, is used for facilitating system functions such as initial random access, channel probing, or short messaging. Methods and techniques are devised to ensure that the mutual interference between the overlapped signals is minimized to have insignificant impact on either signal and that both signals are detectable with expected performance by a receiver.

Abstract: Methods and systems for contingency communication are disclosed. In one embodiment, a method for providing emergency services may be performed by a base station operating in a communication system In an embodiment, the method for providing emergency services includes transmitting a beacon signal to indicate an emergency status to enable portable devices to operate in a stress mode. A distress signal may be transmitted by a mobile device in response to the beacon signal to the base station, wherein the distress signal carries information at least comprising user identity associated with the mobile device, geolocation of the mobile device, or biometrics of a user of the mobile device.

Abstract: Methods and apparatus for multi-carrier communication with variable channel bandwidth are disclosed, where the time frame structure and the OFDM symbol structure are invariant and the frequency-domain signal structure is flexible. In one embodiment, a mobile station, upon entering a geographic area, uses a core-band to initiate communication and obtain essential information and subsequently switches to full operating bandwidth of the area for the remainder of the communication. If the mobile station operates in a wide range of bandwidths, the mobile station divides the full range into sub-ranges and adjusts its sampling frequency and its FFT size in each sub-range.

Abstract: A signal receiver is configured to receive multiple time-domain input signals. A plurality of the input signals among the multiple time-domain input signals is selected and transformed into frequency-domain signals. The frequency-domain signals are shifted in phase by a negative value of a respective reference phase, and the phase-shifted signals are combined into one signal. The combined signal is then multiplied with a stored signal to generate a signal product and transformed into a time-domain signal. Peak detection is performed on the time-domain signal.

Abstract: Methods, apparatus, and other technology are disclosed for collaborative transmission in a wireless communication system. In one embodiment, a transmitter receives control information from a receiver in the wireless communication system. The control information indicates time-frequency resources allocated or assigned for data transmission by the transmitter. The transmitter sends configuration information to a second transmitter in the wireless communication system. The configuration information includes indication of the time-frequency resource allocation or assignment. The transmitter to the second transmitter the data which to be transmitted to the receiver using the allocated time-frequency resources.

Abstract: Methods and apparatus in a multi-carrier cellular wireless network with random access improve receiving reliability and reduce interference of uplink signals of a random access, while improving the detection performance of a base station receiver by employing specifically configured ranging signals.

Abstract: A profile of interference received by the mobile station is estimated from one or more neighboring base stations. The profile of interference may be a function of frequency within a channel bandwidth. The profile of interference is quantized. An uplink signal is transmitted to a serving base station, wherein the uplink signal carries the quantized profile of interference.

Abstract: Methods and systems are disclosed for communicating in a wireless communications system utilizing a plurality of frequency bands for downlink (DL) transmission and a plurality of frequency bands for uplink (UL) transmission. In an embodiment, a mobile device receives a DL signal via a DL frequency band. The DL signal contains DL-UL frequency-band association information. The DL signal is decoded to obtain the DL-UL frequency-band association information which is used to determine a UL frequency band for UL transmission. The mobile device configures its radio-frequency (RF) circuitry to operate in the UL frequency band for UL transmission.

Abstract: A method and apparatus for content multicasting and broadcasting and data unicasting in a broadband multicarrier wireless communication system. A base station is configured to transmit, and a mobile station is configured to receive, a sequence of consecutive frames. The frames comprise two types: frames containing time-frequency resources for content multicasting and broadcasting via a single frequency network, and frames containing time-frequency resources for data unicasting without the use of a single frequency network. The two types of frames are intermixed in accordance with an intermixing configuration pattern. The intermixing configuration pattern is indicated by a bit-map contained in a scheduling signal.

Abstract: In a broadband wireless communication system, a primary control signal may be relocated within the operation band for transmission while avoiding interference. For example, if the primary control signal employs P contiguous subcarriers, the primary control signal can be placed in any section of the band that has P contiguous subcarriers. If a narrow-band interferer appears at one end of the band, the primary control signals can be placed at the other end. If the interferer appears in the middle, the primary can be relocated to either end of the band. The placement of primary control signals can be changed as the interference environment changes.

Abstract: Methods and systems for contingency communication are disclosed. In one embodiment, a method for providing emergency services may be performed by a base station operating in a communication system. In an embodiment, the method for providing emergency services includes transmitting a beacon signal to indicate an emergency status to enable portable devices to operate in a stress mode. A distress signal may be transmitted by a mobile device in response to the beacon signal to the base station, wherein the distress signal carries information at least comprising user identity associated with the mobile device, geolocation of the mobile device, or biometrics of a user of the mobile device.