37 results about "Channel knowledge" patented technology

A bidirectional signal processing method uses parallel transmission of digital transmitted data streams in a multiple input-multiple output system. Related art methods generate high bit error rates mostly in singular transmission channels. For this reason, the rank-adaptive signal processing method provides that the number nd of active subchannels are varied according to the actual channel behavior in order to effect a robust data transmission even in singular radio channels based on a transmit-side and receive-side channel knowledge and a modification of the data vector by a linear matrix vector multiplication while introducing a factor gamma for limiting the maximum transmit power. The maximum transmit power is then only distributed to the currently activated subchannels so that no transmit power remains unused. Another optimization of the number of subchannels nd occurs when selecting the modulation and encoding methods. During the optimal rank-adaptation according to the water-filling principle, another power is allocated to each subchannel. Another modulation and encoding method is accordingly selected for each data stream. During the suboptimal rank-adaptation according to the channel inversion principle, all subchannels have the same power whereby enabling the data streams to be modulated and encoded in a common source.

An apparatus for use in transmit beamforming to a beamformee having NR receive antennas. The apparatus includes a controller configured to i) construct a partial channel matrix that describes a multiple input, multiple output (MIMO) channel between a beamformer and M receive antennas, wherein M is less than NR, and ii) generate L independent vectors using the partial channel matrix, wherein L is a rank of the partial channel matrix. When a number NS of one or more streams is greater than L, the controller is further configured to i) select the L independent vectors as steering vectors to steer L streams of the plurality of streams, and ii) select NS−L orthogonal vectors in a null space of the L independent vectors as steering vectors to steer a remainder of the streams in the plurality of streams.

A system and method for transmitter and receiver operation for multiple-input, multiple-output (MIMO) communications based on prior channel knowledge are provided. A method for receiver operations includes receiving a data block, determining if there is confidence in information related to a channel, detecting data in the data block with a first detector in response to determining that there is confidence in the information, and detecting the data in the data block with a second detector in response to determining that there is no confidence in the information. The data block is received over the channel.

A method in a transmitter for selecting steering vectors for simultaneously transmitting a plurality of streams (NS) between the transmitter and a receiver, where the receiver has NR receive antennas, where the transmitter knows respective channels associated with M receive antennas of the receiver, and where M is less than NR, includes constructing a partial channel matrix that describes a multiple input, multiple output (MIMO) channel between the transmitter and the M receive antennas, generating L independent vectors using the partial channel matrix, wherein L is a rank of the partial channel matrix, selecting a respective steering vector for each of the plurality of streams to be transmitted to the receiver, including, if NS is less than or equal to L, selecting NS of the L independent vectors as the steering vectors, and, if NS is greater than L, (i) selecting the L independent vectors as steering vectors to steer L of the plurality of streams; and (ii) selecting NS−L orthogonal vectors in a null space of the L independent vectors.