Transmitter and MIMO multiplex transmission method
In MIMO multiplex transmission accompanied by precoding, a reduction of peak power is realized while minimizing deterioration of transmission quality. The present MIMO multiplex transmission method includes a step of generating transmission data corresponding to a plurality of streams to be transmitted simultaneously, a step of performing precoding so that the transmission data is received by a receiver as data orthogonal to each other, a step of applying amplitude clipping to the precoded transmission data in stream units to suppress peaks of the entire transmission power, and a step of suppressing allocation of interference power caused by the amplitude clipping to streams in a good channel state.
1. A transmitter comprising:
a transmission data generating section configured to generate transmission data simultaneously transmitted in a plurality of streams;
a precoding section configured to perform precoding so that the transmission data is received by a receiver as data orthogonal to each other;
a peak suppressing section configured to apply amplitude clipping to the precoded transmission data in stream units to suppress peaks of entire transmission power;
a filtering section configured to filter interference power leaking out of the band caused by the amplitude clipping of the peak suppressing section; and
an interference allocation controlling section configured to allocate in-band interference power caused by the amplitude clipping to streams in a poor channel state in a concentrated manner, wherein
the transmitter transmits, using MIMO multiplexing, the transmission data in the plurality of streams which are spatially multiplexed, according to the allocation of the in-band interference power by the interference allocation controlling section, and each of the plurality of streams has a frequency bandwidth.
2. The transmitter according to claim 1 , wherein the interference allocation controlling section allocates the in-band interference power to the streams in a poor channel state based on a repetition algorithm.
3. The transmitter according to claim 2 , wherein the interference allocation controlling section comprises a determining section configured to determine an end of repetition processing according to peak power after the peak suppression processing by the peak suppressing section or a repetition count by the repetition algorithm.
4. The transmitter according to claim 1 , wherein the precoding section applies one precoding matrix of a plurality of precoding matrixes to each frequency block of a plurality of frequency blocks in a frequency selective fading channel, and
the interference allocation controlling section allocates the in-band interference power caused by the amplitude clipping to the streams in a geed poor channel state for each of the frequency blocks.
5. A MIMO multiplex transmission method comprising the steps of:
generating transmission data to be simultaneously transmitted in a plurality of streams;
performing precoding so that the transmission data is received by a receiver as data orthogonal to each other;
applying amplitude clipping to the precoded transmission data in stream units to suppress peaks of the entire transmission power;
filtering interference power leaking out of the band caused by the amplitude clipping;
allocating in-band interference power caused by the amplitude clipping to streams in a poor channel state in a concentrated manner; and
transmitting, using MIMO multiplexing, the transmission data in the plurality of streams which are spatially multiplexed, according to the allocation of the in-band interference power, each of the plurality of streams having a frequency bandwidth.