92results about How to "Improved channel estimation" patented technology

A method and apparatus for providing information indicating radio resources for multi-cell interference measurement at a BS so that a UE can more accurately measure interference are disclosed.

The present invention relates to improved multiple access communications. In one form, the invention relates to an improved signal processing method and apparatus for an iterative method of determining the reception of a signal in a multi user packet based wireless OFDM (Orthogonal Frequency Division Multiplexing) communication system. In other forms the present invention provides recursive filtering for joint iterative decoding in a variety of systems and functions such as linear multiple access channel decoders, iterative equalisation, iterative joint channel estimation and detection / decoding, iterative space-time processing, iterative multi user interference cancellation and iterative demodulation. In one particular form the present invention provides an iterative decoding circuit for a wireless multiuser communications receiver comprising a first signal processing means for receiving at least one received signal, said first signal processing means comprising at least two linear iterative filters such that the first linear iterative filter provides an estimate of a selected received signal to an estimated signal output and a second linear iterative filter provides estimates of at least one other received signal, delayed by one iteration cycle, to an input of said first linear iterative filter, a second signal processing means for receiving the estimated signal output of the first linear iterative filter and providing a further received signal estimate to the input of the first signal processing means in a succeeding iteration cycle of the decoding circuit.

A method of estimating a channel length (304) in a wireless receiver is disclosed. The receiver receives a signal (122) from a remote transmitter. The receiver selects a plurality (K) of different candidate channel lengths and determines a respective criterion value (402) of the signal for each of the plurality of different candidate channel lengths. The receiver selects a channel length (410) from the plurality of different candidate channel lengths in response to the respective criterion value (404).

Methods, systems, and devices for wireless communication are described. One method includes identifying a plurality of intermediate precoders corresponding to a plurality of tone subsets. The plurality of intermediate precoders define a plurality of vectors across the plurality of tone subsets. The method further includes selecting, for each vector of the plurality of vectors, a subset of non-frequency domain components of the vector, such as time-domain components; modifying the plurality of intermediate precoders to a plurality of smoothed precoders based at least in part on the selected subset of non-frequency domain components for each vector; and precoding a plurality of transmit streams using the plurality of smoothed precoders. The plurality of smoothed precoders is smoothed in a frequency domain compared to the plurality of intermediate precoders. Smoothing precoders may enable application of wideband channel estimation techniques using user equipment (UE)-specific reference signals.

The invention relates to a time division duplex transmission method for a broadband wireless communication system, belonging to the technical field of digital information transmission. The method comprises the following steps: using a time / frequency-domain unified orthogonal frequency division multiple access (TFU-OFDMA) technology to carry out downlink multiple access so as to obtain downlink signals at a transmitting end of a base station; using a time / frequency-domain unified single carrier multiple access (TFU-SCMA) technology to carry out uplink multiple access so as to obtain uplink signals at a transmitting end of user equipment; and using a time division duplex frame structure to carry out duplex transmission on the downlink signals and the uplink signals. The TFU-OFDMA technology provided by the invention solves the multiple access problems in the TFU-OFDM (Time / Frequency-domain Unified Orthogonal Frequency Division Multiplexing) modulation process, can flexibly allocate wireless resources and can effectively overcome deep fade, narrow-band interference and the like. The TFU-SCMA technology provided by the invention solves the multiple access problems in the improved SC-FDE (Single Carrier Frequency Domain Equalization) modulation process, reserves the advantages of low complexity of the transmitting end in the SC-FDE technology, low peak-to-average power ratio and the like, and enables the receiving end to be subject to synchronization and channel estimation better.

An apparatus and method for transmitting a message in a mobile communication system are provided, in which a short message is generated to be sent together with a preamble signal on the RACH, for uplink transmission, the short message and the preamble signal are spread with different orthogonal spreading codes, the phase of the short message is rotated to be orthogonal to the phase of the preamble signal, the phase-rotated short message is added to the preamble signal, and the sum is sent.

Aspects of the present disclosure provide for enhanced channel estimation in a wireless communication network. Uplink channel estimation may be enhanced by increasing the uplink transmit power of an uplink reference signal. For example, the uplink transmit power may be increased by multiplying a measured downlink path loss by a predetermined factor to produce an increased downlink path loss and calculating the uplink transmit power based on the increased downlink path loss. Downlink channel estimation may be enhanced by increasing a number of tones on a downlink reference signal assigned to a scheduled entity relative to the number of tones assigned to other scheduled entities.

The invention provides a feedback-type channel estimation method and device based on a PN sequence and a pilot frequency in an OFDM system, said method obtains an impulse channel estimation of this OFDM symbol by obtaining a channel impulse response of a pseudo-random (PN) sequence of a received signal; then by obtaining a channel estimation of the pilot frequency symbol; and then by combining the former two results with a channel estimation of a previous OFDM symbol. The new channel estimation method of this invention can complete the interpolation function It has the advantages of high performances and low complexity, and is particular useful for OFDM system in high speed and long delay multi-path environment.

Equipment for transmitting a signal, the equipment comprising an antenna array (600-606) for providing three or more radiation antenna patterns. The equipment is arranged to transmit a primary common pilot signal with at most two radiation patterns and a secondary common pilot signal with at least one radiation pattern. The equipment comprises controllers (622a-622d) for adjusting the power ratio between the primary and the secondary common pilot signal and the total power of the primary and the secondary common pilot signals, and controllers (614a-614d) for adjusting the transmit power of the dedicated pilot signal, such that the power levels of the dedicated pilot signals transmitted with the same radiation patterns as the secondary common pilot signal are relatively higher than the power levels of the dedicated pilot signals transmitted with the same radiation patterns as the primary common pilots.

The application provides a method for sending a reference signal and a device for sending a signal. The method for sending the reference signal includes the following steps: generating a first reference signal according to a data signal, an interference relationship between adjacent carrier waves, and a predefined second reference signal; modulating and sending the data signal and the first reference signal on corresponding carrier by utilization of a non-orthogonal multi-carrier modulation waveform. The application also discloses a method for receiving the reference signal and a device for receiving the signal. According to the application, the utilization rate of carrier resources can be improved, and the interference on the reference signal can be reduced, so that the better channel estimation and synchronization performance can be provided.

A method and apparatus for providing information indicating radio resources for multi-cell interference measurement at a BS so that a UE can more accurately measure interference are disclosed.