Multi-antenna transmission device, multi-antenna reception device, multi-antenna transmission method, multi-antenna reception method, terminal device, and base station device
View Patent ↗Provided is a multi-antenna transmission device ( 400 ) which can perform MLD by using a simple configuration of a reception device in a MIMO-AMC system. The multi-antenna transmission device ( 400 ) includes common signal point mapping units ( 401, 402 ) for mapping data transmitted from different antennas ( 111, 112 ) in transmission scheme using MIMO spatial multiplexing, to common signal points shared by respective modulation methods. Thus, the arrangement of baseband signal points obtained by mapping a code word after channel encoding onto an IQ plane can be shared as common signal points shared by modulation methods. Accordingly, the reception device need not prepare a particular circuit for performing MLD calculation in accordance with a combination of the methods for modulating the signals which have been MIMO-space multiplexed. This can reduce the circuit size of the MLD calculation circuit.
1. A multi-antenna transmitting apparatus comprising:
a mapping section that maps data transmitted from different antennas in a transmission scheme using multiple-input multiple-output spatial-multiplexing, to a signal point shared by respective different modulation schemes so that average transmission power of each modulation scheme is the same as or of the same order as a pilot signal; and
a transmitting section that transmits a modulated signal obtained by execution of mapping of the same or different modulation schemes by the mapping section, using multiple-input multiple-output spatial-multiplexing scheme.
2. The multi-antenna transmitting apparatus according to claim 1 , wherein the mapping section shares some signal points of respective modulation schemes so that average transmission power of each modulation scheme is the same as or of the same order as a pilot signal.
3. A multi-antenna transmitting apparatus comprising:
a mapping section that maps data transmitted from different antennas in a transmission scheme using multiple-input multiple-output spatial-multiplexing, to a signal point according to respective different modulation schemes;
a pilot signal generation section that generates a pilot signal for which a signal point arrangement differs for each modulation scheme and in which a relative position of a signal point of a signal with respect to a signal point of the mapping section is shared by respective different modulation schemes so that average transmission power of one modulation scheme is the same as or of the same order as that of another modulation scheme; and
a transmitting section that transmits a modulated signal obtained by the mapping section and a pilot signal generated by the pilot signal generation section, using multiple-input multiple-output spatial-multiplexing scheme.
4. A multi-antenna receiving apparatus comprising:
a receiving section that receives at a plurality of antennas a spatial-multiplexed signal transmitted by a multi-antenna transmitting apparatus;
a channel estimation section that estimates a condition of a communication channel traversed by the spatial-multiplexed signal; and
an MLD arithmetic calculation section that performs maximum likelihood detection arithmetic calculation using a channel estimation value from the channel estimation section and also using a signal point shared by respective different modulation schemes, wherein the signal point is on a constellation defined such that an average transmission power of one modulation scheme is the same as or of the same order as an average transmission power of another modulation scheme as a candidate signal point.
5. A multi-antenna receiving apparatus comprising:
a receiving section that receives at a plurality of antennas a spatial-multiplexed signal in which signal points of respective different modulation schemes are shared so that average transmission power of each modulation scheme is the same as or of the same order as a pilot signal;
a channel estimation section that estimates a condition of a communication channel traversed by the spatial-multiplexed signal; and
a maximum likelihood detection arithmetic calculation section that performs maximum likelihood detection arithmetic calculation using a channel estimation value from the channel estimation section and also using a relative position of a signal point of each modulation scheme as a reference point of a pilot signal.
6. A multi-antenna transmitting method comprising:
a mapping step of mapping data transmitted from different antennas in a transmission scheme using multiple-input multiple-output spatial-multiplexing, to a signal point shared by respective different modulation schemes so that an average transmission power of one modulation scheme is the same as or of the same order as an average transmission power of another modulation scheme; and
a step of transmitting a modulated signal obtained by execution of mapping of the same or different modulation schemes in the mapping step, using multiple-input multiple-output spatial-multiplexing scheme.
7. A multi-antenna receiving method comprising:
a receiving step of receiving at a plurality of antennas a spatial-multiplexed signal transmitted by a multiantenna transmitting apparatus;
a channel estimation step of estimating a condition of a communication channel traversed by the spatial-multiplexed signal; and
an maximum likelihood detection arithmetic calculation step of performing maximum likelihood detection arithmetic calculation using a channel estimation value estimated by the channel estimation step and also using a signal point shared by respective different modulation schemes, wherein the signal point is on a constellation defined such that an average transmission power of one modulation scheme is the same as or of the same order as an average transmission power of another modulation scheme as a candidate signal point.
8. A terminal apparatus that performs multi-antenna communication using preceding with a base station apparatus, the terminal apparatus comprising:
a channel estimation section that performs channel estimation using a received pilot signal and generates a channel estimation matrix;
a QR decomposition section that performs QR decomposition of a channel estimation matrix generated by the channel estimation section; and
an R matrix nondiagonal element phase amount arithmetic calculation section that calculates a phase amount of phase components in a non-diagonal position in the upper triangle within an R matrix obtained by QR decomposition by the QR decomposition section, that feeds back information indicative of the phase components of elements of complex number to the base station apparatus.
9. The terminal apparatus according to claim 8 , further comprising an R matrix element amplitude ratio arithmetic calculation section that takes a specific element among elements present at a position in an upper triangle within an R matrix obtained by QR decomposition by the QR decomposition section as a reference, calculates an amplitude ratio with respect to the element taken as a reference for an element other than the specific element in an upper triangle of the R matrix, and feeds back an amplitude ratio obtained by the arithmetic calculation to the base station.
10. The terminal apparatus according to claim 9 , wherein the R matrix element amplitude ratio arithmetic calculation section, when quantizing information of the amplitude ratio, performs quantization so that, for areas obtained by dividing a quantization object, a binary value assigned to a first area and a binary value assigned to an area adjacent to the first area are binary values that differ by only 1 bit.
11. The terminal apparatus according to claim 8 , wherein the R matrix non-diagonal element phase amount arithmetic calculation section, when quantizing information of the phase component, performs quantization so that, for areas obtained by dividing a quantization object, a binary value assigned to a first area and a binary value assigned to an area adjacent to the first area are binary values that differ by only 1 bit.
12. A base station apparatus that performs multi-antenna communication using precoding with a terminal apparatus, the base station apparatus comprising:
a transmit signal point generation section that has a plurality of precoding matrices that become candidates, and generates a transmit signal point by multiplying a post-mapping signal by the precoding matrix that becomes a candidate;
an inter-candidate-signal-point square Euclidean distance arithmetic calculation section that reproduces an R matrix using R matrix amplitude ratio information and phase information fed back from the terminal apparatus, generates a candidate signal point using the reproduced R matrix and a transmit signal point generated by the transmit signal point generation section, and computes a square Euclidean distance between the generated candidate signal points;
a preceding matrix selection section that selects a preceding matrix such that a square Euclidean distance computed by the inter-candidate-signal-point square Euclidean distance arithmetic calculation section becomes a maximum; and
a precoding section that multiplies a preceding matrix selected by the preceding matrix selection section by a post-mapping signal point.
13. A base station apparatus that performs multi-antenna communication using precoding with a terminal apparatus, the base station apparatus comprising:
a transmit signal point generation section that, when sharing a signal point between different modulation schemes, generates a transmit signal point that is shared by a plurality of sharing methods;
an inter-candidate-signal-point square Euclidean distance arithmetic calculation section that reproduces an R matrix using R matrix amplitude ratio information and phase information fed back from the terminal apparatus, generates a candidate signal point using the reproduced R matrix and a transmit signal point generated by the transmit signal point generation section, and computes a square Euclidean distance between the generated candidate signal points;
a common signal point selection section that selects a signal point sharing method from among the plurality of sharing methods such that a square Euclidean distance computed by the inter-candidate-signal-point square Euclidean distance arithmetic calculation section becomes a maximum; and
a common signal point mapping section that performs mapping to a modulation signal point using a signal point sharing method selected by the common signal point selection section.