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: 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: 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: 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 sub carriers, 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: 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: Methods and apparatus disclosed maximize the capacity of serving cells and minimize inter-cell interferences due to power emission from serving cells in a multi-carrier, multi-cell communication system. The control methods and apparatus take into account various factors such as cell configuration, frequency reuse, geometry and path-loss information, transmission priority, subchannel configuration, feedback from other cells, or any combination thereof, and produce signals that control the transmission power levels and the modulation and coding of transmitted signals.

Abstract: Hybrid ARQ is employed in a multi-carrier communication system for retransmission of erroneous packets by taking advantage of time/frequency/space diversity and by combining ARQ functions at physical layer and MAC layers, making the multi-carrier system more robust in a high packet-error environment.

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: 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 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 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: Methods and systems for correction of frequency errors in multi-carrier communication systems. The composite frequency error associated with the downlink signals are used to infer or derive the composite frequency error associated with the uplink signals, which are used to pre-compensate the uplink signals. Special signal components are transmitted by multiple base stations to facilitate frequency-error estimation and other system control functionalities at a mobile device. The mobile device carries out temporal, spatial, or spatial-temporal processing of the composite frequency errors associated with one or more base stations to determine the clock frequency error and the Doppler shift with respect to its serving base station.

Abstract: Hybrid ARQ is employed in a multi-carrier communication system for retransmission of erroneous packets by taking advantage of time/frequency/space diversity and by combining ARQ functions at physical layer and MAC layers, making the multi-carrier system more robust in a high packet-error environment.

Abstract: A first uplink signal is transmitted by a mobile station to a base station on a first set of subcarriers in a first OFDM symbol. The first set of subcarriers is modulated with a first signal sequence known to both the mobile station and the base station. A second uplink signal is transmitted by the mobile station to the base station on a second set of subcarriers in a second OFDM symbol. The second set of subcarriers is modulated with the first signal sequence or a transform of the first signal sequence. The second set of subcarriers is modulated with a second signal sequence containing attribute information on a third set of subcarriers of a downlink signal received by the mobile station over a downlink channel. The correspondence between the subcarriers in the third and second set is known to the mobile station and the base station.

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 is shifted in phase by a negative value of a respective reference phase, and the phase-shifted signals is 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.

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: 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 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 for communicating in a multi-carrier communication system are disclosed. Radio resources may be organized in at least three hierarchical levels. The hierarchical levels may comprise macroblocks, blocks, and radio resource elements. A macroblock may contain a plurality of blocks and a block may contain a plurality of radio resource elements. The radio resource elements may further correspond to subcarriers in an orthogonal frequency division multiplexing (OFDM) symbol. An index in a control message may specify a modulation and/or coding scheme (MCS) pattern indicting a MCS for each block within a macroblock. In an embodiment, fewer bits are used by the index to specify a MCS pattern that is used statistically more frequently, and more bits are used by the index to specify a MCS pattern that is used statistically less frequently. Signals may be transmitted over the plurality of macroblocks.