Abstract: A method and apparatus of a subscriber station selecting a subset of a plurality of antennas for uplink transmission are disclosed. One method includes a base station transmitting a cyclic delay diversity transmission signal. The subscriber station receives the cyclic delay diversity transmission signal through the plurality of antennas. The subscriber station selects a subset of the plurality of antennas based on a received quality signal parameter. The subscriber station transmits uplink signals to the base station through the selected subset of the plurality of antennas.

Abstract: The invention provides methods and systems for channel estimation. A method comprises receiving a plurality of signal frames, comprising at least a first zone and a second zone, from a plurality of base stations in the wireless communication system. Two or more first delay profiles corresponding to two or more base stations are determined using the first zone. The method further comprising detecting at least one aliased tap in a time domain channel response of the second zone using the two or more first delay profiles. Another method comprises receiving a signal frame, comprising at least a preamble symbol and a data part, from a base station. A first delay profile corresponding to the preamble symbol is determined and a second delay profile corresponding to the data part is obtained. The first delay profile is analyzed in conjunction with the second delay profile to detect one or more aliased taps in a time domain channel response of the data part. The detected one or more aliased taps are nulled/rectified.

Abstract: A method and apparatus for estimating frequency offset and timing offset of a first Mobile Station (MS) in a communication system is provided. The method includes receiving a composite signal at a plurality of receiver antennas of a Base Transceiver Station (BTS). The composite signal includes a first signal transmitted from a first MS and a second signal transmitted from a second MS. The composite signal includes one or more tiles. Each tile includes a plurality of data sub-carriers, a plurality of first pilot sub-carriers, and a plurality of second pilot sub-carriers. A total phase offset of the first MS is estimated based on a complex conjugate product of pilot symbols of the plurality of first pilot sub-carriers. Thereafter, a first phase offset corresponding to the timing offset of the first MS is estimated based on a Power Delay Profile (PDP) of one or more first pilot sub-carriers.

Abstract: A method and system of estimating frequency offset at a subscriber station is disclosed. The method includes the subscriber station receiving a composite signal, in which the composite signal includes multi-carrier signals transmitted from a plurality of base stations. The subscriber station selects a subset of the plurality of base stations. The subscriber station selects at least one pair of multi-carrier symbols of the composite signal, wherein each of the at least one pair of multi-carrier symbols include a plurality of pilot sub-carriers. The subscriber station selects a subset of the plurality of pilot sub-carriers of the at least one pair of multi-carrier symbols based on transmit pilot symbols of the pilot sub-carriers of the multi-carrier signals transmitted by the subset of the plurality of base stations.

Abstract: A method and apparatus of synchronization and frame structure determination of a base station are disclosed. One method includes the base station determining an initial frame structure including an active region and a dummy region, wherein the regions are sets of OFDM symbols. The base station receives timing information from at least one of a mobile station and a second base station, wherein the mobile station is simultaneously communicating with the base station and the second base station. The base station adjusts its frame structure based at least in part on the timing information, wherein adjusting its frame structure includes at least one of adjusting the active region and the dummy region. The base station adjusts its internal timing to improve synchronization with the second base station based on the timing error information.

Abstract: A method and system of training a communication system is disclosed. The method includes a first transceiver transmitting signals through one or more antennas of the first transceiver. A second transceiver selects a subset of a plurality of antennas of the second transceiver, wherein the selected subset provides a largest aggregate received signal power. The second transceiver transmits pilots on a subset of sub-carriers of multi-carrier signals through the selected subset of the plurality of antennas of the second transceiver. The first transceiver receives the pilots, and extracts channel knowledge from the received pilots.

Abstract: Embodiments described herein include methods for improving the SINR, and therefore communication quality or rate, in the downlink of a cellular communication system. In an embodiment, the system is an orthogonal-frequency-division multiple-access (OFDMA) system. In an embodiment, a set of terminals is designated a coordinated-transmission group. The set of terminal is chosen such that the slot-allocations of the set are given special treatment to alleviate interference from other sectors or cells. In an embodiment, “zones” defined in the WiMax standard are “repurposed” to handle the coordinated-transmission, although the zone was originally intended for another purpose.

Abstract: Method and system for wireless communication in an Orthogonal Frequency Division Multiplexing (OFDM) communication system is disclosed. The method involves receiving a plurality of receive-signals over a first set of antennas. Further, one or more of the plurality of receive-signals are cyclically delayed to generate one or more cyclically delayed receive-signal. Subsequently, one or more of the plurality of receive-signals are combined with one or more of the cyclically delayed receive-signals. In other words, the method involves performing receive Cyclic Delay Diversity (CDD).

Abstract: A method and apparatus for wireless transmission from a mobile unit to a base station includes multiplexing a pilot signal and a data signal, wherein the data signal operates at a data rate by splitting the data signal into a plurality of data streams; applying a pilot gain to the pilot channel, wherein the data gain and the pilot gain are a function of the data rate; and combining the plurality of data streams and the pilot signal into a subset of sub-carriers. The subset of sub-carriers are transmitted using Discrete Fourier Transform Spread OFDMA.

Abstract: Systems and methods are provided for improving a channel estimate in a signal communication system. The systems and methods improve the channel estimation quality and/or the delay spread of the channels that can be estimated. The combining of symbols operates to increase the density of pilots that are processed to provide the channel estimate.

Abstract: Embodiments described herein include methods for improving the SINR, and therefore communication quality or rate, in the downlink of a cellular communication system. In an embodiment, the system is an orthogonal-frequency-division multiple-access (OFDMA) system. In an embodiment, a set of terminals is designated a coordinated-transmission group. The set of terminal is chosen such that the slot-allocations of the set are given special treatment to alleviate interference from other sectors or cells. All terminals within a coordination group generally use the same slot, but embodiments are not so limited.

Abstract: Embodiments for at least one method and apparatus of a subscriber station transceiver allocating and transmitting groups of subcarriers between a plurality of transceiver antennas are disclosed. One method includes the subscriber station transceiver receiving at least one downlink signal through each of the plurality of subscriber station antennas. The subscriber station transceiver characterizes a received signal of the at least one downlink signal over multiple subcarriers. The subscriber station transceiver allocates groups of subcarriers for uplink transmission through each of the plurality of subscriber antennas, wherein the allocation is based on the characterized received signal of the at least one downlink signal over multiple subcarriers.

Abstract: Methods and systems for estimating channel of one or more MSs in a collaborative MIMO communication system are provided. The method includes receiving a signal transmitted from a transmit antenna of a first MS and a transmit antenna of a second MS at a BTS using one or more receiver antennas. The method further includes computing one or more conjugate products for each of the first MS and the second MS using the signal. Thereafter, an average is determined over the plurality of receiver antennas and the plurality of tiles of the plurality of conjugate products for each of the first MS and the second MS. A phase determined based on the average of the plurality of conjugate products for the first MS and the second MS is divided into a first phase and a second phase for each of the first MS and the second MS. Additionally, the method includes determining a channel estimate for each tile of the first MS and the second MS at each receiver antennas.

Abstract: In a method for synchronization of a mobile radio receiver to a base station, the received signal is sampled using oversampling, by which means sample values are obtained from different sampling phases. The oversampled signal is correlated with a local code, with sample values that are associated with a first sampling phase being processed with a frequency offset with respect to sample values that are associated with a second sampling phase.

Abstract: A method for managing uplink communication in wireless communication network is provided. The method includes selecting one or more Mobile Stations (MSs) from a plurality of MSs based on a first signal parameter corresponding to each MS of the one or more MSs, one or more second signal parameters corresponding to each MS of the one or more MSs, and one or more threshold parameters. The first signal parameter is associated with a Base Station (BS) serving a MS. Further, the one or more second signal parameters are associated with one or more BSs neighboring to the MS. The one or more threshold parameters are associated with a communication parameter. Thereafter, the method includes modifying uplink Modulation and Coding Scheme (MCS) level of the one or more MSs.

Abstract: Embodiments for a method and apparatus of selecting a transmission mode between the subscriber and a base station are disclosed. One method includes determining a predictive window. Instantaneous channel quality measurements are averaged, wherein the averaging is dependent upon a size of the predictive window. A first estimate of the transmission mode is determined based on the averaged instantaneous channel quality measurements. A margin is calculated based on reception of a qualifying downlink transmission. The transmission mode is selected by updating the first estimate with the margin.

Abstract: A method and apparatus for link adaptation in a wireless communication network is provided. The method includes computing a first channel quality parameter based on one or more channel quality parameters. The one or more channel quality parameters are associated with a communication link between a Mobile Station (MS) and a Base Station (BS). The method further includes determining a qualifying transmission unit to compute a correction parameter. The correction parameter is computed based on the first channel quality parameter and one or more transmission parameters. The one or more transmission parameter is associated with the communication link. Thereafter, the method schedules a transmission mode of the communication link based on a second channel quality parameter. The second channel quality parameter is estimated based the first channel quality parameter and the correction parameter.

Abstract: A method and apparatus of determining a hand-off metric is disclosed. One method includes a subscriber receiving identifications of a neighboring set of base stations from a serving base station. From the neighboring set, the subscriber determines an active set of base stations. The active set is determined by the subscriber measuring received signal power from each of the base stations of the neighboring set at first discrete points in time, averaging the received signal power for each of the base stations of the neighboring set, and selecting the active set based on the average received signal power of the base stations of the neighboring set. Determining the at least one hand-off metric further includes the subscriber measuring at second discrete points in time an excess received signal power for each base station of the active set, wherein the excess received signal power includes signal power received by the subscriber in excess of power received from the base station.

Abstract: A method and apparatus of selecting which of a plurality of receiver chains of a mobile unit to receive wireless signals, is disclosed. One method includes measuring a first receive signal quality while all of the plurality of receiver chains are receiving wireless signals, and measuring a second receive signal quality while a subset of the plurality of receiver chains are receiving wireless signals. The subset of the plurality of receiver chains are selected to receive wireless signal unless the first receive signal quality is a threshold better than the second receive signal quality. If the first receive signal quality is a threshold better than the second receive signal quality then all the plurality of receiver chains are selected to receive wireless signals.

Abstract: Methods assigning mobile users in a half-frequency division duplex (HFDD) system to a first UL group and second UL group of an uplink (UL) sub-frame, and to a first DL group and a second DL group of a downlink (DL) sub-frame, wherein the UL sub-frame is assigned a first carrier frequency and the DL sub-frame is assigned a second carrier frequency, are disclosed. One method includes determining a type of data, determining a receive CINR (carrier interference plus noise ratio), and determining a Doppler frequency parameter, for each mobile user of a plurality of mobile users.