Abstract: A method for estimating a feedback channel for a wireless repeater detects changes in a power of a remote signal. When a large power swing in the remote signal is detected, the method operates to discard samples or blocks of samples of the pilot and receive signals and a final channel estimate is generated using undiscarded samples of the pilot and receive signals. Alternately, sub channel estimates are generated using individual blocks of the pilot samples and receive samples. When a large power swing in the remote signal is detected, the method operates to discard one or more sub channel estimates and a final channel estimate is generated using undiscarded sub channel estimates.

Abstract: When a UE does not completely decode a packet transmitted from a base station, the UE may send ACK/NACK to the base station, upon which the base station may retransmit the packet based on the ACK/NACK. However, the ACK/NACK fails to provide the base station with information needed by the UE for completely decoding the packet. Accordingly, a method, an apparatus, and a computer program product for wireless communication are provided. The apparatus receives a packet from a base station having a first MCS, determines information to provide to the base station, wherein the information comprises CQI relating to a channel condition and/or interference condition corresponding to time-frequency resources allocated for the received packet, and sends the information to the base station. Thereafter, the apparatus re-receives the packet from the base station, the re-received packet having a second MCS according to the information sent to the base station.

Abstract: Techniques for transmitting data using single-carrier frequency division multiple access (SC-FDMA) multiplexing schemes are described. In one aspect, data is sent on sets of adjacent subbands that are offset from one another to achieve frequency diversity. A terminal may be assigned a set of N adjacent subbands that is offset by less than N (e.g., N/2) subbands from another set of N adjacent subbands assigned to another terminal and would then observe interference on only subbands that overlap. In another aspect, a multi-carrier transmission symbol is generated with multi-carrier SC-FDMA. Multiple waveforms carrying modulation symbols in the time domain on multiple sets of subbands are generated. The multiple waveforms are pre-processed (e.g., cyclically delayed by different amounts) to obtain pre-processed waveforms, which are combined (e.g., added) to obtain a composite waveform. A cyclic prefix is appended to the composite waveform to generate the multi-carrier transmission symbol.

Abstract: Pilot transmission and channel estimation techniques for an OFDM system with excess delay spread are described. To mitigate the deleterious effects of excess delay spread, time filtering is utilized. Time filtering is utilized to combat excess delay spread effects in channel estimation. The time filtering is performed in the presence of staggered pilots and helps in improving the channel estimate in the presence of excess delay spread.

Abstract: A wireless repeater includes a gain control metric computation block to compute a gain control metric for use in controlling the variable gain of the repeater. The gain control metric is computed by downsampling the gain control input signal to the gain control metric computation block and also downsampling the computed correlation and normalization terms. The gain control metric may be further enhanced by filtering the computed metric values using linear or non-linear filtering.

Abstract: A channel structure has at least two channel sets. Each channel set contains multiple channels and is associated with a specific mapping of the channels to the system resources available for data transmission. Each channel set may be defined based on a channel tree having a hierarchical structure. To achieve intra-cell interference diversity, the channel-to-resource mapping for each channel set is pseudo-random with respect to the mapping for each remaining channel set. In each scheduling interval, terminals are scheduled for transmission on the forward and/or reverse link. The scheduled terminals are assigned channels from the channel sets. Multiple terminals may use the same system resources and their overlapping transmissions may be separated in the spatial domain. For example, beamforming may be performed to send multiple overlapping transmissions on the forward link, and receiver spatial processing may be performed to separate out multiple overlapping transmissions received on the reverse link.

Abstract: A wireless repeater includes an echo canceller to cancel an estimated feedback amount from an input signal and a reference receiver to sample a portion of the transmit signal prior to over-the-air transmission for use as the reference signal for channel estimation. More accurate channel estimation is obtained by using the reference signal from the reference receiver as the reference signal accounts for distortions in the transmitter circuit of the repeater.

Abstract: Pilot transmission and channel estimation techniques for an OFDM system with excess delay spread are described. To mitigate the deleterious effects of excess delay spread, the number of pilot subbands is greater than the cyclic prefix length. This “oversampling” may be achieved by using more pilot subbands in each symbol period or different sets of pilot subbands in different symbol periods. In one example, a first set of pilot subbands may be received in a first symbol period, and a second set of pilot subbands may be received in a second symbol period. The first set of pilot subbands and the second set of pilot subbands may be staggered in frequency.

Abstract: Techniques for transmitting pilot and for processing received pilot to obtain channel and interference estimates are described. A terminal may generate pilot symbols for a first cluster in a time frequency block based on a first sequence and may generate pilot symbols for a second cluster in the time frequency block based on a second sequence. The first and second sequences may include common elements arranged in different orders and may be considered as different versions of a single sequence. The terminal may transmit the pilot symbols in their respective clusters. A base station may obtain received pilot symbols from multiple clusters in the time frequency block. The base station may form each of multiple basis vectors with multiple versions of the sequence assigned to the terminal and may process the received pilot symbols with the multiple basis vectors to obtain a channel estimate for the terminal.

Abstract: In accordance with aspects of the disclosure, a method, apparatus, and computer program product for wireless communication may include receiving a plurality of signals from a plurality of receiving donor antennas, delaying at least one of the received signals from at least one of the receiving donor antennas, combining the delayed signal with at least one of the other received signals from at least one other receiving donor antenna to generate a combined signal, amplifying the combined signal, and transmitting the amplified combined signal via a transmitting antenna.

Abstract: To transmit a multi-carrier signal, a transmitter provides zero symbols for guard subbands, performs OFDM modulation, and filters the resultant time-domain samples with a pulse shaping filter. To transmit a single-carrier signal, the transmitter partitions the single-carrier signal into segments. Each segment contains up to K samples and is padded, if needed, to the length of an OFDM symbol. Each padded segment is transformed from the time domain to the frequency domain to generate a corresponding frequency-domain segment with K symbols. For each frequency-domain segment, the symbols corresponding to the guard subbands are set to zero. Each frequency-domain segment is then transformed from the frequency domain to the time domain to generate a corresponding time-domain segment. A cyclic prefix may or may not be appended to each time-domain segment. Each time-domain segment is filtered with the same pulse shaping filter to generate an output waveform for the single-carrier signal.

Abstract: A method and apparatus are provided to manage the assignment transmission resource of forward and reserve link that is assigned to transmitting entity for a period of time. An indication of a gap is provided whenever the transmitting entity is not transmitting actual data packets (e.g. whole or part of intended data or content), yet the transmitting entity is to maintain the assignment of the allocated resource. For example, an erasure signature packet comprising a first data pattern is transmitted on the assigned resource when there is no actual data to transmit on the assigned resource.

Abstract: A method for monitoring feedback loop stability in a wireless repeater includes measuring a gain control metric in the feedback loop of the repeater periodically for a given time period where the gain control metric is indicative of a loop gain of the feedback loop of the repeater; and monitoring the magnitude of the gain control metric to determine the stability of the feedback loop of the repeater. In operation, a large magnitude of the gain control metric indicates instability in the feedback loop of the repeater.

Abstract: A wireless repeater in a multi-repeater environment operates to detect the presence of neighboring repeaters and to maintain repeater stability in the presence of a neighboring repeater. In some embodiments, the repeater transmits a known signal sequence to discover the presence of a neighboring repeater. When a neighboring repeater is detected, the repeater may apply mitigation measures to maintain operational stability at the repeater.

Abstract: A wireless repeater incorporates a gain management block to implement a multi-parameter gain management algorithm. The gain management algorithm receives gain settings from at least a gain control metric for stability and output signal quality and signal headroom values associated with circuitry of the repeater. The gain management block provides secure and robust boot-up of the repeater as well as oscillation detection and prevention. Furthermore, the gain management block implements repeater stability control, output signal-to-noise level control, uplink and downlink gain balance control and compensation for device constraints.

Abstract: A method for controlling gain in a wireless repeater includes using two or more gain control metrics indicative of stability of the repeater, at least two of the gain control metrics having different integration lengths, where the integration length is the sum of the coherent integration time and the non coherent integration time, and controlling a variable gain value of the repeater based on one or more of the selected gain control metric(s) where the gain control metric(s) to use is selected based on the stability of the repeater.

Abstract: A channel structure has at least two channel sets. Each channel set contains multiple channels and is associated with a specific mapping of the channels to the system resources available for data transmission. Each channel set may be defined based on a channel tree having a hierarchical structure. To achieve intra-cell interference diversity, the channel-to-resource mapping for each channel set is pseudo-random with respect to the mapping for each remaining channel set. In each scheduling interval, terminals are scheduled for transmission on the forward and/or reverse link. The scheduled terminals are assigned channels from the channel sets. Multiple terminals may use the same system resources and their overlapping transmissions may be separated in the spatial domain. For example, beamforming may be performed to send multiple overlapping transmissions on the forward link, and receiver spatial processing may be performed to separate out multiple overlapping transmissions received on the reverse link.

Abstract: Methods and apparatus for estimating a loop delay value (Ndelay) in an interference cancellation repeater are presented. For example, a method may include setting a repeater gain to an initial gain value, setting a delay parameter to an initial time value, and measuring a loop gain associated with the delay parameter and the repeater gain by detecting a feedback signal with an echo canceller disabled. The method may further include determining whether the measured loop gain is larger than a previously measured loop gain, and if so, designating the delay parameter as the loop delay value (Ndelay); and decrementing the delay parameter when the measured loop gain is not larger than the previously measured loop gain, and when the delay parameter is not at a final time value. The method may iterate until the delay parameter is less than or equal to the final time value.

Abstract: A method and apparatus are provided to manage the assignment transmission resource of forward and reserve link that is assigned to transmitting entity for a period of time. An indication of a gap is provided whenever the transmitting entity is not transmitting actual data packets (e.g. whole or part of intended data or content), yet the transmitting entity is to maintain the assignment of the allocated resource. For example, an erasure signature packet comprising a first data pattern is transmitted on the assigned resource when there is no actual data to transmit on the assigned resource.

Abstract: Techniques for transmitting pilot and for processing received pilot to obtain channel and interference estimates are described. A terminal may generate pilot symbols for a first cluster in a time frequency block based on a first sequence and may generate pilot symbols for a second cluster in the time frequency block based on a second sequence. The first and second sequences may include common elements arranged in different orders and may be considered as different versions of a single sequence. The terminal may transmit the pilot symbols in their respective clusters. A base station may obtain received pilot symbols from multiple clusters in the time frequency block. The base station may form each of multiple basis vectors with multiple versions of the sequence assigned to the terminal and may process the received pilot symbols with the multiple basis vectors to obtain a channel estimate for the terminal.