摘要:
According to the present invention, the effects of the transmission medium on transmitted information symbols are estimated separately from other effects, e.g., those associated with receive and transmit filters, using knowledge of the pulse shaping. The medium response estimate is then used to detect information symbols. Previously, receivers had used estimates of the composite channel to detect symbols. This, however, assumed uncorrelated noise, which is not always the case.
摘要:
According to the present invention, the effects of the transmission medium on transmitted information symbols are estimated separately from other effects, e.g., those associated with receive and transmit filters, using knowledge of the pulse shaping. The medium response estimate is then used to detect information symbols. Previously, receivers had used estimates of the composite channel to detect symbols. This, however, assumed uncorrelated noise, which is not always the case.
摘要:
According to the present invention, the effects of the transmission medium on transmitted information symbols are estimated separately from other effects, e.g., those associated with receive and transmit filters, using knowledge of the pulse shaping. The medium response estimate is then used to detect information symbols. Previously, receivers had used estimates of the composite channel to detect symbols. This, however, assumed uncorrelated noise, which is not always the case.
摘要:
Demodulation and interference parameter estimation in an OFDM receiver is improved by identifying regions, in a two-dimensional array of time-frequency transmission positions, having related interference parameters, such as resulting from the same pre-coding scheme, transmission rank, transmitting antennas, and the like. An interference measure is estimated for each of a plurality of time-frequency positions. The interference measures are analyzed by considering them as pixels, or picture elements, in a two-dimensional image, and applying image processing algorithms to identify the regions having related interference parameters. The image processing algorithms may include operations such as edge detection, segmentation, and/or clustering. The receiver may perform interference suppression or cancellation such as interference rejection combining of data extracted from signals received within an identified time-frequency region having related interference parameters.
摘要:
Demodulation and interference parameter estimation in an OFDM receiver is improved by identifying regions, in a two-dimensional array of time-frequency transmission positions, having related interference parameters, such as resulting from the same pre-coding scheme, transmission rank, transmitting antennas, and the like. An interference measure is estimated for each of a plurality of time-frequency positions. The interference measures are analyzed by considering them as pixels, or picture elements, in a two-dimensional image, and applying image processing algorithms to identify the regions having related interference parameters. The image processing algorithms may include operations such as edge detection, segmentation, and/or clustering. The receiver may perform interference suppression or cancellation such as interference rejection combining of data extracted from signals received within an identified time-frequency region having related interference parameters.
摘要:
The quality of a received signal in a non-linear receiver is estimated using a coupling matrix G or Q that describes the interaction of symbols in the received signal with other symbols and/or how the impairment (noise and interference) interacts in the received signal. The coupling matrix is also useful for joint detection. The signal quality estimate may include, e.g., the minimum eigenvalue, and other functions, such as the determinant and trace of the coupling matrix. When G or Q varies with each block, as in CDMA systems employing longcode scrambling, a representative matrix can be used, such as a matrix of RMS values or average magnitudes of real and imaginary components. The signal quality estimate can be expressed as a bit error rate (BER).
摘要:
A receiver comprises plural receive antennas and electronic circuitry. The plural receive antennas are configured to receive, on plural subcarriers transmitted over a radio interface, a frequency domain signal that comprises contribution from a block of time domain symbols. The electronic circuitry is configured or operable to perform symbol detection of time domain symbols comprising the block by performing a multi-stage joint detection procedure comprising plural stages, and thus serves as a detector (40). For a first stage the block is divided into a first number of sub-blocks each having a sub-block first size. For a second stage the block is divided into a second number of sub-blocks each having a sub-block second size, the sub-block second size being greater than the sub-block first size. For each stage a detector (40) formulates frequency domain combining weights and uses the frequency domain combining weights for combining multiple receive versions of each subcarrier to provide candidate symbol combination values for symbols in each sub-block of the respective stage. For the second stage the detector (40) is further configured to use the candidate symbol combination values of the first stage to formulate joint hypotheses to serve as candidates for the joint detection operation of the second stage.
摘要:
A pilot channel signal for time-division multiplexing with one or more traffic channel signals in a broadcast/multi-cast signal and for code-division multiplexing with a continuously transmitted pilot channel signal is described. In an exemplary method for transmitting a broadcast/multicast signal, a pilot symbol sequence is obtained for each slot of one or more frames of the broadcast/multicast signal, so that the pilot symbol sequence varies for each slot of a given frame. The pilot symbol sequence for each slot is spread with a channelization code, and the spread pilot symbol sequence for each slot is scrambled, using a scrambling code, to form a first pilot channel signal. The first pilot channel signal is transmitted so that it is time-division multiplexed with one or more traffic channel signals transmitted during each slot and code-division multiplexed with a second pilot channel signal transmitted during all slots of the one or more frames.
摘要:
Methods and apparatus for determining an impairment covariance matrix for use in an interference-suppressing CDMA receiver are disclosed. In several of the disclosed embodiments, precise information regarding signal propagation delays is not needed. An exemplary method includes the selection of a plurality of processing delays for processing a received CDMA signal. Net channel coefficients for the processing delays are estimated and used to calculate an impairment covariance matrix. The impairment covariance matrix is calculated as a function of the estimated net channel coefficients and the processing delays, without estimating a propagation medium channel response for the received signal.
摘要:
In one of its aspects, the technology concerns a method of processing a signal which includes physical data channels which have been channelized using spreading codes. The method comprises (1) despreading unoccupied spreading codes (e.g., codes which are essentially unobscured by traffic data) included in the signal to obtain unoccupied code despread values, (2) using the unoccupied code despread values to form an impairment covariance matrix; and (3) using the impairment covariance matrix along with a channel estimate to form a processing parameter. The processing parameter can be one of combining sets and a signal quality estimate. In another of its aspects, the technology concerns a coherent, linear equalizer apparatus configured to process a signal which includes physical data channels which have been channelized using spreading codes. The equalizer apparatus comprises plural delay fingers (32) configured to despread unoccupied spreading codes included in the signal to obtain unoccupied code despread values, and a generator (60) configured to use the unoccupied code despread values to form an impairment covariance matrix.