Abstract: Apparatuses and methodologies are described that enhance performance in a wireless communication system using beamforming transmissions. According to one aspect, the channel quality is monitored. Channel quality indicators can be used to select a scheduling technique, such as space division multiplexing (SDM), multiple-input multiple output (MIMO) transmission and opportunistic beamforming for one or more user devices. In addition, the CQI can be used to determine the appropriate beam assignment or to update the beam pattern.

Abstract: To select a rate for a transmitter in a communication system, a receiver obtains a channel response estimate and a received SINR estimate for the transmitter, e.g., based on a pilot received from the transmitter. The receiver computes a hypothesized SINR for the transmitter based on the channel response estimate and the received SINR estimate. The receiver then selects a rate for the transmitter based on (1) the hypothesized SINR and (2) characterized statistics of noise and interference at the receiver for the transmitter, which may be given by a probability density function (PDF) of SINR loss with respect to the hypothesized SINR. A look-up table of rate versus hypothesized SINR may be generated a priori for the PDF of SINR loss. The receiver may then apply the hypothesized SINR for the transmitter to the look-up table, which then provides the rate for the transmitter.

Abstract: Transmission patterns for pilot symbols transmitted from a mobile station or base station are provided. The pattern allows for improved receipt of the pilot symbols transmitted. In addition, schemes for improving the ability to multiplex pilot symbols without interference and/or biasing from different mobile stations over the same frequencies and in the same time slots.

Abstract: Techniques for controlling transmit power and the amount of overlapping in a quasi-orthogonal system are described. A base station for a sector receives transmissions from terminals in that sector and neighbor sectors and determines performance metrics (e.g., overall throughput) and/or QoS metrics (e.g., minimum data rate) for the terminals in the sector. The base station updates an overlapping factor based on the performance metrics and updates a QoS power control parameter based on the QoS metrics. The overlapping factor indicates the average number of overlapping transmissions sent simultaneously on each time-frequency block usable for data transmission. The QoS power control parameter ensures that the terminals in the sector can achieve minimum QoS requirements. A power control mechanism with multiple loops is used to adjust the transmit power of each terminal. The overlapping factor and QoS power control parameter are updated by two of the loops.

Abstract: Transmission patterns for pilot symbols transmitted from a mobile station or base station are provided. The pattern allows for improved receipt of the pilot symbols transmitted. In addition, schemes for improving the ability to multiplex pilot symbols without interference and/or biasing from different mobile stations over the same frequencies and in the same time slots.

Abstract: Transmission patterns for pilot symbols transmitted from a mobile station or base station are provided. The pattern allows for improved receipt of the pilot symbols transmitted for frequency selective channels and users. In addition, schemes for improving the ability to multiplex pilot symbols without interference and/or biasing from different mobile stations over the same frequencies and in the same time slots.

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 apparatuses are disclosed that determine whether to feedback, and the amount of feedback, with respect to eigenbeam information based upon channel resources. Additionally, methods and apparatuses are disclosed that determine whether to feedback, and the amount of feedback, with respect to eigenbeam information based upon channel information and changes in channel information.

Abstract: Methods and apparatuses are disclosed that determine a type of channel information based upon whether a wireless device is scheduled to receive symbols. In addition, a determination may be as to a number of hop periods to determine the type of channel information. Further, a distance between hop regions may be utilized to determine a type of channel information.

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: 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: Efficient pilot transmission schemes for multi-antenna communication systems are described. In general, MISO receivers prefer a pilot transmitted in one spatial direction, and MIMO receivers typically require a pilot transmitted in different spatial directions. In one pilot transmission scheme, a first set of T scaled pilot symbols is generated with a first training vector and transmitted (e.g., continuously) from T transmit antennas, where T>1. If MIMO receiver(s) are to be supported by the system, then at least T?1 additional sets of T scaled pilot symbols are generated with at least T?1 additional training vectors and transmitted from the T transmit antennas. The training vectors are for different (e.g., orthogonal) spatial directions. Each MISO receiver can estimate its MISO channel based on the first set of scaled pilot symbols. Each MIMO receiver can estimate its MIMO channel based on the first and additional sets of scaled pilot symbols.

Abstract: Each transmitter is assigned a time-only pilot code, a frequency-only pilot code, or a time-frequency pilot code to use for pilot transmission. The pilot codes may be pseudo-random, orthogonal, and/or cyclic-shift codes. To obtain a channel estimate for a transmitter using a time-frequency pilot code composed of a time-only code and a frequency-only code, a receiver multiplies a set of received symbols for each symbol period with a set of code values for the frequency-only code to obtain a set of detected symbols and performs an IDFT on the set of detected symbols to obtain an initial impulse response estimate. The receiver performs code matching on multiple initial impulse response estimates derived for multiple symbol periods with the time-only code to obtain a final impulse response estimate for the desired transmitter. The receiver retains the first L channel taps and zeroes out remaining channel taps, where L is the expected channel length.

Abstract: A channel estimation system comprises a filtering component that selectively scales a plurality of carriers as a function of location of the plurality of carriers within a frequency band, wherein the plurality of carriers comprises at least one data carrier and at least one pilot carrier. A component thereafter extrapolates an observation from the at least one pilot carrier, wherein a channel is estimated as a function of the extrapolated observation. The scaling of the carriers facilitates reducing a flooring effect associated with channel estimation. The filtering component can be employed at a transmitter and/or at a receiver, and can be activated and/or deactivated as a function of a sensed data packet type.

Abstract: A MIMO communication system is adapted to encode multiple data streams at the same adaptable rate. Accordingly, the set of all possible modulation/rate combinations to all modulations with common rates is decreased thus resulting in the reduction of the number of possible packet formats carrying the data streams. Rate prediction is made more error-resilient, in part, due to the averaging over all information rates. Furthermore, the signaling overhead of the packets is reduced. Therefore, the tradeoff between the desired transmission rate granularity on the one hand, and robustness/signaling overhead on the other hand, is controlled by adjusting the coding rate.

Abstract: Dynamic resource allocation systems, apparatus, and methods are disclosed for selectively improving the ability of a receiver to determine a channel estimate in an Orthogonal Frequency Division Multiple Access (OFDMA) system. A wireless communication system can use a common pilot channel configuration to aid channel estimation in one or more receivers in communication with the system. A receiver in communication with the system may be unable to demodulate received data due to an inaccurate channel estimate. The receiver can communicate to a transmitter in the system a request for additional channel estimation resources. The wireless communication system can provide additional channel estimation resources by inserting dedicated pilot channels into one or more of the frequencies allocated to symbols for the receiver. If the receiver is still unable to demodulate received data, the wireless communication system can incrementally insert additional pilot channels in the symbol associated with the receiver.

Abstract: A transmitter generates multiple composite pilots with a training matrix and a gain matrix. Each composite pilot includes multiple training pilots generated with multiple columns of the training matrix and scaled with multiple gain elements in a column of the gain matrix. The transmitter transmits each composite pilot via multiple transmit antennas. A MISO receiver obtains received symbols for the multiple composite pilots and derives an estimate of a composite MISO channel. For OFDM, the MISO receiver derives an initial impulse response estimate for each composite pilot, filters the initial impulse response estimates for all composite pilots, and derives a frequency response estimate for the composite MISO channel. A MIMO receiver obtains and processes received symbols for the multiple composite pilots based on the training and gain matrices and derives channel estimates for individual SISO channels between the multiple transmit antennas and multiple receive antennas.

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: Accordingly, a method and apparatus are provided to convert received content into a first stream and a second stream, to transmit said first stream using a first tone and to transmit said second stream using an orthogonal scheme. A layering scheme is used to transmit the base stream covering a smaller area and an enhanced stream is used to cover a large utilizing orthogonal scheme.