摘要:
Aspects of the present disclosure describe an efficient channel estimation algorithm for high-speed processing of dedicated reference signals. The channel estimation algorithm may utilize one or more compressed interpolation matrices. The compressed interpolation matrices may be selected based on the Doppler value and signal to noise ratio (SNR) of the channel.
摘要:
A delayed channel estimation is a channel state information (CSI) reference subframe having an index (NCSI—ref) belonging to NCSI—ref=N−4−k, where N is the subframe index on which the CSI is to be transmitted on an uplink, and k is the smallest value of k>=0, such that N−4−k belongs to a given configuration set. When k is too large, the selected CSI reference subframe is too outdated to produce accurate CSI. An undelayed channel estimation is a CSI reference subframe having an index (NCSI—ref) belonging to NCSI—ref=N−4. When the CSI reference subframe N−4 does not belong to the given subframe restriction subset, the selected channel estimate may be too noisy to produce accurate CSI. A method for CSI computation for enhanced inter-cell interference coordination (eICIC) selects between a delayed channel estimation and an undelayed channel estimation for computing CSI, for example, based on a signal metric. The CSI is computed with a selected channel estimation.
摘要:
In order to cancel any interference due to the second cell signal (e.g., from a non-serving cell) from a signal received at a UE, without receiving additional control information, the UE blindly estimates parameters associated with decoding the second cell signal. This may include determining a metric based on sets of symbols associated with the cell signals in order to determine parameters for the second cell signal, e.g., the transmission mode, modulation format, and/or spatial scheme of the second cell signal. The parameters for the signal may be determined based on a comparison of the metric with a threshold. When a spatial scheme and a modulation format is unknown, the blind estimation may include determining a plurality of constellations of possible transmitted modulated symbols associated with a potential spatial scheme and modulation format combination. Interference cancellation can be performed using the constellations and a corresponding probability weight.
摘要:
In a wireless communication system, interference on data tones is estimated by detecting data transmissions from interferers. An overall interference covariance matrix is estimated as a function of scalar traffic to pilot ratio (TPR) estimates, residual interference covariance estimates, and covariance of channel estimates of dominant interferers. The interference estimates are refined as a function of reliability based on a ratio of power received from a serving cell and power received from a dominant interferer.
摘要:
Interference on pilot signals and on data tones can be mismatched. Different types of interference estimates perform differently based on how the mismatch occurs. The resulting interference estimate may thus be inaccurate. Interference estimates based on pilot signals and also on data tones can both be evaluated for reliability. The more reliable of the two can then be selected. If the data tones estimate is selected, the estimate can be calculated from covariance matrices or from traffic-to-pilot ratios.
摘要:
Techniques for transmitting UE-specific reference signals (UE-RSs) in a wireless network are described. In an aspect, a UE-RS may be transmitted in different manners depending on the number of layers used for data transmission. In one design, a cell may determine subcarriers for a UE-RS based on a frequency shift if data is transmitted on one layer and based on a predetermined set of subcarriers (with no frequency shift) if data is transmitted on multiple layers. In another aspect, a UE-RS may be transmitted on subcarriers determined based on a frequency shift for data transmission on multiple layers. In yet another aspect, a UE-RS may be transmitted from a plurality of cells to a UE for coordinated multi-point (CoMP). In yet another aspect, a UE-RS may be transmitted in a data section of a subframe including only the data section.
摘要:
Techniques for transmitting UE-specific reference signals (UE-RSs) in a wireless network are described. In an aspect, a UE-RS may be transmitted in different manners depending on the number of layers used for data transmission. In one design, a cell may determine subcarriers for a UE-RS based on a frequency shift if data is transmitted on one layer and based on a predetermined set of subcarriers (with no frequency shift) if data is transmitted on multiple layers. In another aspect, a UE-RS may be transmitted on subcarriers determined based on a frequency shift for data transmission on multiple layers. In yet another aspect, a UE-RS may be transmitted from a plurality of cells to a UE for coordinated multi-point (CoMP). In yet another aspect, a UE-RS may be transmitted in a data section of a subframe including only the data section.
摘要:
Methods and apparatus in a wireless communication system are described for receiving and processing transmit power control commands, where, for example, the response to the transmit power control commands is conditionally decoupled from at least one of a transmit bandwidth parameter, a transport format parameter and a power stepsize limit. This Abstract is provided for the sole purpose of complying with the Abstract requirement rules that allow a reader to quickly ascertain the disclosed subject matter. Therefore, it is to be understood that it should not be used to interpret or limit the scope or the meaning of the claims.
摘要:
Techniques for computing and reporting channel quality indication (CQI) are described. In an aspect, a plurality of CQI computation methods may be supported, and each CQI computation method may indicate how CQI should be computed. One CQI computation method may be selected for use. CQI may then be computed and reported in accordance with the selected CQI computation method. In an exemplary design, a user equipment (UE) may obtain a selected method for computing CQI, which may be chosen based on the UE capability and/or other factors. The selected method may specify (i) CQI computation for a specific codeword among a plurality of codewords or (ii) CQI computation by averaging signal quality across a plurality of layers used for transmission. The UE may compute CQI in accordance with the selected method, send the CQI to a base station, and receive data sent by the base station based on the CQI.
摘要:
Techniques for sending control information in a manner to improve reliability are described. In an aspect, control information may be sent on multiple control channels, which may be independently configured and operated, in order to improve reliability. In one design, a base station may send signaling to instruct at least one UE to receive control information on both a first control channel (e.g., a Physical Downlink control Channel (PDCCH)) and a second control channel (e.g., a Relay PDCCH (R-PDCCH)). The base station may send control information for the at least one UE on the first and second control channels, e.g., in different time and/or frequency regions of a subframe. In another aspect, control information may be sent on a control channel in multiple subframes with bundling to improve reliability. A user equipment (UE) may perform the complementary processing to recover the control information sent by the base station on multiple control channels or with bundling.