Digital Signal Processing Reference
In-Depth Information
Chapter 2
Interference Cancellation and Detection for
MAC with Two Users
2.1 Channel Model
In this chapter, we assume a quasi-static flat Rayleigh fading channel model for
the channel as shown in Fig.
2.1
. The path gains are independent complex Gaussian
random variables and fixed during the transmission of one block. There are two users
each with two transmit antennas and one receiver with two receive antennas.
At the first two time slots, the channel matrices for Users 1 and 2 are
h
11
h
12
h
21
h
22
g
11
g
12
g
21
g
22
H
=
,
G
=
(2.1)
respectively, where
h
ij
and
g
ij
are i.i.d.
CN
.
At the first two time slots, Users 1 and 2 transmit Alamouti codes
(
0
,
1
)
c
1
−
s
1
−
c
2
s
2
C
=
,
S
=
(2.2)
c
1
s
1
c
2
s
2
respectively. At time slots 1 and 2, the received signals are respectively denoted by
y
1
y
2
y
1
y
2
y
1
y
2
=
,
=
(2.3)
We assume that the transmitter and receiver know the channel information perfectly.
Let
a
11
a
12
a
21
a
22
a
11
a
12
a
21
a
22
A
1
A
2
=
,
=
(2.4)
denote the precoders of User 1 at time slots 1 and 2, respectively. Also,
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