摘要:
Techniques for transmitting data with limited channel information are described. A transmitter (e.g., a base station) obtains channel information for a subset of multiple antennas used for data reception at a receiver (e.g., a terminal). The channel information may include at least one channel response vector for at least one antenna, which is a subset of the multiple antennas at the receiver. The transmitter derives multiple eigenvectors based on the channel information, e.g., using pseudo eigen-beamforming. The transmitter selects at least one eigenvector from among the multiple eigenvectors and transmits data with the selected eigenvector(s). The transmitter may select and use different subsets of eigenvector(s) in different time intervals. The transmitter may arrange the multiple eigenvectors into multiple sets based on their eigenvalues, select at least one set based on a MIMO transmission rank, and select one eigenvector from each set.
摘要:
Apparatuses and methodologies are described that enhance performance in a wireless communication system using beamforming transmissions. According to one aspect, a set of transmit beams are defined that simultaneously provides for space division multiplexing, multiple-input multiple output (MIMO transmission and opportunistic beamforming. The addition of a wide beam guarantees a minimum acceptable performance for all user devices.
摘要:
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.
摘要:
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.
摘要:
Techniques to enhance the performance in a wireless communication system using segments called subbands and using precoding are shown. According to one aspect, the bandwidth for transmission to an access terminal is constrained to a preferred bandwidth which is less than the bandwidth available for transmission to an access terminal and precoding information related to the subcarriers within the constrained bandwidth is provided to a transmitter. The precoding information related to the subcarriers within a constrained bandwidth provides feedback about the forward link channel properties relative to different subbands and may be fed back on a channel associated with the bandwidth.
摘要:
Embodiments are described in connection with enhancing performance in a wireless communication system using codebook technology. According to an embodiment is a method for enhancing performance in a wireless communication environment. The method can include receiving a user preference for a transmission mode, associating the user preference with an entry or entries in a codebook, and assigning the user to a transmission mode corresponding to the entry or entries. The transmission mode can be one of a preceding, space division multiple access (SDMA), SDMA preceding, multiple input multiple output (MIMO), MIMO preceding, MIMO-SDMA and a diversity. Each entry can correspond to a transmission mode.
摘要:
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.
摘要:
Techniques to facilitate estimating the frequency response of a wireless channel in an OFDM system are provided. The method and systems allow for combining signal information across multiple communication channels at one or more channel tap delays in order to determine appropriate taps for channel information.
摘要:
Transmission schemes that can flexibly achieve the desired spatial multiplexing order, spatial diversity order, and channel estimation overhead order are described. For data transmission, the assigned subcarriers and spatial multiplexing order (M) for a receiver are determined, where M≧1. For each assigned subcarrier, M virtual antennas are selected from among V virtual antennas formed with V columns of an orthonormal matrix, where V≧M. V may be selected to achieve the desired spatial diversity order and channel estimation overhead order. Output symbols are mapped to the M virtual antennas selected for each assigned subcarrier by applying the orthonormal matrix. Pilot symbols are also mapped to the V virtual antennas. The mapped symbols are provided for transmission from T transmit antennas, where T≧V. Transmission symbols are generated for the mapped symbols, e.g., based on OFDM or SC-FDMA. Different cyclic delays may be applied for the T transmit antennas to improve diversity.
摘要:
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.