Abstract: Methods and apparatus of allocating antennas for cyclic delay diversity (CDD) transmission are disclosed. One method includes estimating a transmission channel of a transceiver having a plurality of antennas. A subset of a plurality of transceiver antennas is selected based on the estimated transmission channel. A single transceiver antenna of the subset is identified based on a channel quality of a transmission path of the single transceiver antenna. Cyclic delay diversity (CDD) signals are transmitted from the subset of the plurality of antennas, wherein a minimally delayed CDD signal is transmitted from the identified single transceiver antenna of the subset of the plurality of transceiver antennas.

Abstract: Estimating a location of a subscriber, including receiving a request for the location, identifying a serving base station of the subscriber, receiving a downlink frame from the serving base station, obtaining a time delay of a signal transmitted between the subscriber and the serving base station, the obtaining including estimating a time of arrival by extracting information from the received downlink frame, the extracting including, determining a channel impulse response of the downlink frame, and estimating the time of arrival by comparing a peak time of the determined channel impulse response with a start time of the downlink frame, the start time being estimated based on the channel impulse response exceeding a predetermined threshold value, estimating a distance between the subscriber and the serving base station based on the time delay, and estimating the location based on the estimated distance between the subscriber and the serving base station.

Abstract: Embodiments of a method and apparatus for performing an adaptive transmission scheme in a frequency division duplexing communication system based on channel state information estimated using an open-loop mode are described herein. In one example, the method includes estimating an impulse response of a channel using a signal received over a first frequency band of the channel from a device, transforming the impulse response into a frequency response of the channel, and subsequently performing the adaptive transmission scheme using the frequency response to transmit a signal to the device over a second frequency band of the channel that is different from the first frequency band.

Abstract: Embodiments of a method and apparatus for selecting one of several different power constraints under which sets of complex, beam weights are normalized are described herein. The embodiments of the method and apparatus specifically select the power constraint based on a code rate used to encode information carried by a transmit signal weighted by the sets of complex, beam weights. Appropriate selection of the power constraint can improve the bit error rate (BER) or block error rate (BLER) of the decoded transmit signal at a receiver.

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: Estimating a location of a subscriber, including receiving a request for the location, identifying a serving base station of the subscriber, receiving a downlink frame from the serving base station, obtaining a time delay of a signal transmitted between the subscriber and the serving base station, the obtaining including estimating a time of arrival by extracting information from the received downlink frame, the extracting including, determining a channel impulse response of the downlink frame, and estimating the time of arrival by comparing a peak time of the determined channel impulse response with a start time of the downlink frame, the start time being estimated based on the channel impulse response exceeding a predetermined threshold value, estimating a distance between the subscriber and the serving base station based on the time delay, and estimating the location based on the estimated distance between the subscriber and the serving base station.

Abstract: A method of aiding uplink transmission is disclosed. One method includes a base station downlink transmitting signals to at least a first terminal, the transmitted signals directed and conveying data to at least the first terminal. The method further includes a second terminal eavesdropping the transmitted signals, and measuring a signal quality. The second terminal estimates uplink channel information based on the measured signal quality, for aiding uplink transmission. Based at least in part on the estimated transmission channel, the second terminal transmits uplink signals to the base station.

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 of estimating a location of a subscriber are disclosed. One method includes receiving a request for the location of the subscriber. The subscriber's serving base station, and a plurality of neighboring base stations sensed by the subscriber, are identified. The subscriber obtains a time delay from the serving base. The subscriber estimates a distance between the subscriber and the serving base station. The subscriber receives frames and estimates a delta time for each of the selected neighboring base stations for the subscriber to synchronize to each of the selected neighboring base stations. The subscriber estimates distances between the subscriber and each of the selected neighboring base. The subscriber location is estimated by trilateration of the distance between the subscriber and the serving base station, and the distances between the subscriber and each of the selected neighboring base stations.

Abstract: Embodiments for space-time coding are disclosed. One method includes establishing a priority for each of a plurality of data streams. A number of data bits for each of the plurality of data streams are allocated. A desired signal quality for each of the plurality of data streams is determined based on the corresponding priority. Each of the plurality of data streams are modulated according to the allocated number of data bits of each of the plurality of data streams. A space-time code is selected for each of the plurality of data streams based at least partially on the desired signal quality for each of the plurality of data streams, wherein at least one of the space-time codes is at least one of a vector or a matrix. Each of the modulated data streams are space-time coded with the selected space-time code. The space-time coded modulated data streams are summed, and transmitted.

Abstract: A method and apparatus of aiding uplink beamforming transmission is disclosed. One method includes a base station downlink transmitting beamformed signals to at least a first terminal, the beam formed signals directed and conveying data to at least the first terminal. The method further includes a second terminal eavesdropping the transmitted beamformed signals, and measuring a signal quality. The second terminal estimates uplink channel information based on the measured signal quality, for aiding uplink transmission. Based at least in part on the estimated transmission channel, the second terminal transmits beamformed uplink signals to the base station.

Abstract: Various embodiments of the present invention recognize at least two zones of operation for a communication device. In a first zone, which is sufficiently spaced away from a human head or body that SAR limits will be met, transmit power delivered to an antenna of a communication device may be maximized within any other constraints under which the communication device operates. In a second zone, which is not sufficiently spaced away from a human head or body, transmit power is redistributed such that SAR limitations are met without affecting the transmit power control loop of the communication device. For example, a second antenna physically disposed at a different location within the communication device may be used either instead of, or in addition to, the first transmit antenna in order that the SAR limits are met.

Abstract: A method and apparatus of a receiver estimating a plurality of channels is disclosed. The method includes the receiver receiving a composite signal. The composite signal includes a signal from each of a plurality of transmission antennas, wherein the signal of each transmission antenna includes a delay relative to other signals of other antennas. The receiver estimates channels between the receiver and the plurality of transmission antennas based on amplitude and a phase of a received composite signal, at a plurality of frequencies.

Abstract: Methods and apparatuses of a mobile subscriber transmitting information to a base station are disclosed. One method includes identifying an uplink transmission condition. If the uplink transmission condition is identified, the mobile subscriber transmits a message over multiple uplink frames using multiple uplink frame types. The mobile subscriber may inform the base station that it is transmitting the message over the multiple uplink frames.

Abstract: Embodiments provide WiFi and WiMAX tailored transceiver radio frequency (RF) filtering techniques and configurations to enable coexistence between WiFi and WiMAX transceivers operating in close proximity. In particular, embodiments provide filtering techniques to reject emissions from WiMAX into WiFi, and vice versa. The filtering techniques eliminate the need for additional isolation between WiMAX and WiFi antennas (approximately 50 dB), which is beyond what is achievable in practice. Embodiments can be tailored according to different use cases of the WiFi and WiMAX transceivers (e.g., fixed CPE, portable router, smart phone with tethering).

Abstract: Methods and apparatus of allocating antennas for cyclic delay diversity (CDD) transmission are disclosed. One method includes estimating a transmission channel of a transceiver having a plurality of antennas. A subset of a plurality of transceiver antennas is selected based on the estimated transmission channel. A single transceiver antenna of the subset is identified based on a channel quality of a transmission path of the single transceiver antenna. Cyclic delay diversity (CDD) signals are transmitted from the subset of the plurality of antennas, wherein a minimally delayed CDD signal is transmitted from the identified single transceiver antenna of the subset of the plurality of transceiver antennas.

Abstract: Methods and apparatuses of a mobile subscriber transmitting information to a base station are disclosed. One method includes identifying an uplink transmission condition. If the uplink transmission condition is identified, the mobile subscriber transmits a message over multiple uplink frames. The mobile subscriber informs the base station that it is transmitting the message over the multiple uplink frames.

Abstract: A method and system of estimating frequency offset at a subscriber station is disclosed. One method includes the subscriber station receiving a composite signal, wherein the composite signal includes multi-carrier signals transmitted from a plurality of base stations. The subscriber station selects a first pair of multi-carrier symbols of the composite signal, wherein each multi-carrier symbol of the first pair of multi-carrier symbols includes a pilot sub-carrier having a common sub-carrier index. The subscriber station selects a second pair of multi-carrier symbols of the composite signal, the second pair having different symbol indices than the first pair, but having a same symbol index separation, wherein each of the multi-carrier symbols of the second pair of multi-carrier symbols includes a pilot sub-carrier having a second common sub-carrier index.

Abstract: A method and system of estimating frequency offset of a subscriber station is disclosed. The method includes the subscriber station receiving a composite signal, wherein 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 includes a plurality of pilot sub-carriers. The subscriber station selects at least one group of the plurality of pilot sub-carriers within 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 estimating a location of a subscriber are disclosed. One method includes receiving a request for the location of the subscriber. The subscriber's serving base station, and a plurality of neighboring base stations sensed by the subscriber, are identified. At least two of the neighboring base stations are selected to aid in estimating the location of the subscriber. Stored locations of the serving base station and the selected neighboring base stations are accessed. The subscriber obtains a time delay from the serving base station for maintaining synchronization of the subscriber with the serving base station. The subscriber estimates a distance between the subscriber and the serving base station based on the time delay. The subscriber receives frames including preambles from each of the selected neighboring base stations, and estimates a delta time for each of the selected neighboring base stations for the subscriber to synchronize to each of the selected neighboring base stations.