摘要:
Interference is estimated in an Orthogonal Frequency Division Multiplexing system by receiving at a wireless receiver pilot symbols and data symbols transmitted in time and frequency via resource blocks, detecting a first one of the data symbols transmitted to the wireless receiver via a time-frequency resource element of a first one of the resource blocks and identifying a second one of the resource blocks adjacent the first resource block having related interference parameters. The interference is estimated based on the pilot symbols transmitted via the first resource block and the pilot symbols transmitted via the second resource block.
摘要:
Teachings herein provide reduced complexity channel state information (CSI) reporting for a successively decoded, precoded multi-antenna transmission. A wireless communication device reports CSI by forming, for each candidate transmission rank of the transmission, a sequence of codewords by iteratively adding codewords allowed for that rank to the sequence. At any given point in the sequence, the device adds the codeword expected to yield the highest individual information rate if decoded at that point in the sequence, considering the different rates possible under different precodings of the transmission. The device then computes, for each rank, a sum information rate across the codewords in the sequence formed for that rank, selects the rank having the highest sum information rate, and reports the selected rank along with the sequence formed for that rank. CSI reporting complexity is reduced because the device constrains its evaluation to only some of the possible decoding sequences.
摘要:
Exemplary embodiments of the present invention describe terminal position location methods and systems. Relative powers of nearby spot beams which are generated by array antennas are determined. For example, powers from six neighboring spot beams relative to a center spot beam within which a mobile station is currently operating, can be measured relative to the power of the center spot beam. Using information from these measurements, the mobile stations position can be determined using, for example, an exponential model of the spot beam pattern.
摘要:
A time-division multiple access (TDMA) base station is disclosed for preserving across-slot signal continuity of signals transmitted in different directions on a given frequency. The base station includes a multi-directional antenna for radiating signals. A processor is operatively coupled to the antenna for generating a first data signal for a first time slot of a TDMA frame including a first pre-determined symbol pattern and a second pre-determined symbol pattern, for generating a second data signal for a second time slot of the TDMA frame including the second predetermined symbol pattern, and for communicating the first data signal and the second data signal to the antenna such that the first data signal is radiated in a first direction and the second data signal is radiated in a second direction. The first data signal is modulated at a first phase for transmission in the first time slot at a first power level in the first direction on the given frequency. The second data signal is modulated at a second phase for transmission in the second time slot at a second power level in the second direction on the given frequency.
摘要:
A plurality of timings are estimated for a received signal wherein the plurality of timings correspond to a plurality of transmitted signals. The received signal is then sampled in accordance with the plurality of timings, to produce a plurality of sample streams from the received signal. Channel estimates are produced for the plurality of transmitted signals and metrics are computed using the sample streams and the channel estimates. Information symbols corresponding to the transmitted signals are detected by using the metrics. Accordingly, by using multiple timings for a received signal, rather than using a common timing, the number of channel taps that are used may be reduced and the accuracy of symbol detection may be increased. The channel estimates may be produced by generating pulse-shape information and producing channel estimates for the multiple transmitted signals using the received signal and the pulse-shape information. Channel estimates may be produced that correspond to a plurality of symbol sequence hypotheses. Channel estimates may be updated using an error signal.
摘要:
In a selective MIMO system, the mobile station provides channel quality feedback for one or more possible transmission mode. The mobile station provides channel quality feedback for a first mode regardless of channel conditions and determines whether to provide feedback for one or more additional modes based on current channel conditions.
摘要:
A receiver reduces interference in a received symbol of interest attributable to an interfering symbol using knowledge of the symbol spreading codes. The receiver comprises a plurality of correlators generating despread values for the received symbol of interest and the interfering symbol, and a combiner to combine the despread values using combining weights calculated based on spreading code correlations between spreading codes for the received symbol of interest and the interfering symbol.
摘要:
A method of supplying channel information in a wireless communication system comprises a mobile terminal normally providing a basic channel report to the wireless communication system; the mobile terminal receiving at least one common feedback criterion broadcast to a plurality of mobile terminals; the mobile terminal determining if the mobile terminal satisfies a condition based on the at least one common feedback criterion; and the mobile terminal selectively providing an enhanced channel report to the wireless communication system based on the determining. The basic channel report may comprise information related to a first set of channel parameters, and the enhanced channel report may provide greater detail on the first set of channel parameters and/or relate to a second set of channel parameters. A method of a base station adaptively controlling channel information reporting by broadcast transmitting at least one common feedback criterion is also presented.
摘要:
An iterative approach is used to find maximum likelihood sequence estimates of a transmitted symbol sequence. Each possible transmitted signal is represented by an indicator vector which selects the transmitted symbol from a symbol library vector. Channel estimates are generated representing the estimated impulse response of the communication channel to each transmitted symbol. The channel estimates are used to form a matched medium response vector and an interaction matrix. The matched medium response vector represents the matched medium response of the receiver to both a transmitter and the channel for each transmitted symbol. The interaction matrix represents the ISI between symbols. The matched medium response vector and the interaction matrix are fed to an estimated symbol probability vector generator which calculates in an iterative manner the estimated symbol probability vectors corresponding to each transmitted symbol. The estimated symbol probability vectors can be output to a hard-decision generator which makes a hard-decision about the transmitted symbols. Alternatively, the estimated symbol probability vectors can be output to a soft-decision decoder.
摘要:
A symbol detector converts initial symbol estimates of received symbols to soft estimates for decoding. The symbol detector computes spreading waveform correlations between a spreading waveform for a symbol of interest and spreading waveforms for one or more interfering symbols. Interference rejection terms are computed by scaling the spreading waveform correlations by corresponding signal powers and compensating for noise. A soft scaling factor for the symbol of interest is computed from the interference rejection terms. The soft scaling factors are then applied to the initial symbol estimates to generate the soft estimates.