Reception-side apparatus and radio communication method
A reception-side apparatus includes: M receive antennas; and a processor configured to execute a first process of acquiring a first signal received from a first transmission-side apparatus from among signals simultaneously received from the N transmission-side apparatuses by receive diversity processing, and acquiring first data by demodulating and decoding the first signal. In the case of N>M, the processor acquires, for each of all patterns of a combination of a first signal, second signals from M−1 transmission-side apparatuses which are to be cancelled by receive diversity processing and third signals from N−M transmission-side apparatuses which are not to be cancelled by the receive diversity processing, a power ratio of power of the first signal relative to total power of the second and third signals based on a predetermined weight and a channel estimate of each signal, and selects a combination with the largest power ratio from among all the patterns.
1 . A method executed by a reception-side apparatus provided with M receive antennas, comprising:
when the M receive antennas receive signals simultaneously from N transmission-side apparatuses which are more than the M receive antennas, wherein all of the signals are sent to the reception-side apparatus,
determining a weight of minimum mean square error (MMSE) using power of signals from N−M transmission-side apparatuses among the N transmission-side apparatuses as a part of interference power; and
acquiring a signal from the signals received from the N transmission-side apparatuses using the weight of MMSE and information indicating propagation characteristics between the M receive antennas using the N transmission-side apparatuses, the acquired signal being from one of the N transmission-side apparatuses other than N−M transmission-side apparatuses.
2 . The method according to claim 1 , wherein
the reception-side apparatus determines the weight of MMSE by a following formula 1, where
a matrix R is a matrix acquired by multiplying a channel matrix H between the N transmission-side apparatuses and the reception-side apparatus by a transmission amplitude of each of the N transmission-side apparatuses;
Pn indicates noise power per receive antenna;
Pi indicates power of interference signals not to be cancelled;
a matrix I is a unit matrix; and
a vector r is a channel vector multiplied by a transmission amplitude of the first signal;
W
mmse
=
{
R
*
R
T
+
(
P
n
+
P
i
)
I
)
-
1
r
1
*
(
Formula
1
)
3 . The method according to claim 1 , wherein
the reception-side apparatus acquires the power of the signals from the N−M transmission-side apparatuses from channel estimates.
4 . The method according to claim 1 , wherein
the reception-side apparatus determines N−M transmission-side apparatuses corresponding to N−M signals having lowest receive power among the signals from the N transmission-side apparatuses as the N−M transmission-side apparatuses.
5 . A reception-side apparatus comprising:
M receive antennas; and
a processor configured to, when the M receive antennas receive signals simultaneously from N transmission-side apparatuses which are more than the M receive antennas, wherein all of the signals are sent to the reception-side apparatus,
determine a weight of minimum mean square (MMSE) using power of signals from N−M transmission-side apparatuses among the N transmission-side apparatuses as a part of interference power; and
acquire a signal from the signals received from the N transmission-side apparatuses using the weight of MMSE and information indicating propagation characteristics between the M receive antennas and the N transmission-side apparatuses, the acquired signal being from one of the N transmission-side apparatuses other than the N−M transmission-side apparatuses.
6 . The reception-side apparatus according to claim 5 , wherein
the processor determines the weight of MMSE by a following formula 1, where
a matrix R is a matrix acquired by multiplying a channel matrix H between the N transmission-side apparatuses and the reception-side apparatus by a transmission amplitude of each of the N transmission-side apparatuses;
Pn indicates noise power per receive antenna;
Pi indicates power of interference signals not to be cancelled;
a matrix I is a unit matrix; and
a vector r is a channel vector multiplied by a transmission amplitude of the first signal,
W
mmse
=
{
R
*
R
T
+
(
P
n
+
P
i
)
I
)
-
1
r
1
*
(
Formula
1
)
7 . The reception-side apparatus according to claim 5 , wherein
the processor is configured to acquire the power of the signals from the N−M transmission-side apparatuses from channel estimates.
8 . The reception-side apparatus according to claim 5 , wherein
the processor determines N−M transmission-side apparatuses corresponding to N−M signals having lowest receive power among the signals from the N transmission-side apparatuses as the N−M transmission-side apparatuses.