Spatial mapping of an OFDM signal to reduce attenuation from an individual transmit antenna in a MIMO transmitter
AssigneeMotorola Mobility LLC
InventorsStephanie Rouquette-Leveil, Marc Bernard De Courville
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Abstract
A method is provided for transmitting a digital signal. The method includes generating a plurality of spatial streams from a digital signal and transforming the spatial streams into a plurality of space-time streams. Each of the space-time streams are cycled in the frequency domain among each of a plurality of transmit antennas. The space-time streams are wirelessly transmitted from the plurality of transmit antennas.
Claims21
A method of transmitting a digital signal, comprising:
- generating a plurality of spatial streams from a digital signal;
- transforming the spatial streams into a plurality of space-time streams;
- cycling in a frequency domain each of the space-time streams among each of a plurality of transmit antennas, including a first antenna and a second antenna, so each space-time stream is successively transmitted by each of the transmit antennas, wherein at least two spatial mapping matrices are selected for the cycling, including a first matrix for use with a first subcarrier and a second matrix, which is different from the first matrix, for use with a second subcarrier, the first matrix mapping each space-time stream entirely to the first antenna, and the second matrix mapping each space-time stream entirely to the second antenna;
- and
- wirelessly transmitting each of the space-time streams from each of the plurality of transmit antennas.
A wireless Multiple-Input-Multiple-Output (MIMO) transmitter, comprising:
- a stream parser for generating a plurality of spatial streams from a digital signal;
- a space time block coder (STBC) for mapping each of the spatial streams to a plurality of space-time streams;
- a spatial mapper for spatially expanding each of the space-time streams by rotating the space-time streams in a frequency domain;
- and
- an analog front end for modulating the spatially expanded space-time streams onto a wireless carrier, the analog front end including a plurality of transmit antennas, including a first antenna and a second antenna, and rotation of the space-time streams in the frequency domain including use of a first spatial mapping matrix with a first subcarrier and a second spatial mapping matrix with a second subcarrier, the second matrix being different from the first matrix;
- wherein the first matrix maps each space-time stream entirely to the first antenna, and the second matrix maps each space-time stream entirely to the second antenna.
At least one non-transitory computer-readable medium encoded with instructions which, when executed by a processor, performs a method including:
- dividing a multicarrier digital signal having a plurality of subcarriers into a plurality of spatial streams;
- mapping the spatial streams into a plurality of space-time streams;
- and
- spatially mapping the space time streams by rotating the space-time streams in a frequency domain so each space-time stream is successively transmitted by each of a plurality of transmit antennas, including a first antenna and a second antenna;
- wherein at least two spatial mapping matrices are selected for the rotating, including a first matrix for use with a first subcarrier and a second matrix, which is different from the first matrix, for use with a second subcarrier, the first matrix mapping each space-time stream entirely to the first antenna, and the second matrix mapping each space-time stream entirely to the second antenna.
Dependencies are inferred from the claim text.