Method and device for multimedia multicast transmission over a wireless network
View Patent ↗A system and a method for multimedia multicast transmission in a mobile wireless network are proposed, which can be applied in a multiple-antenna system as well as a single antenna system. The basic message and additional message are transmitted at the same time. Receivers with different capability also with different complexities are used to demodulate different message. In order to design low-complexity receiver, the signal can be demodulated noncoherently for multimedia transmission.
1. A transmitting method for multimedia multicast in a wireless communication system, comprising:
(a) encoding a basic message using Unitary Space-time coding scheme;
(b) encoding an additional message using a multiple antenna differential encoded space-time coding scheme;
(c) delaying a result of step (b) by T symbol periods;
(d) combining a result of step (b) with the result of step (c);
(e) multiplying the results of steps (a) and (d) in order to obtain a combined message;
(f) post processing a result of step (e) in order to make the signal ready for transmitting; and
(g) transmitting a result of step (f) using at least one transmitter antenna.
2. The method according to claim 1 , wherein step (e) satisfies a subsequent equation:
S ( k )= √{square root over (T)}B p ( k ) D q ( k ), k= 1,2, . . .
where
Bp is a result of step (a), Dq is a result of step (b), and S is a result of step (e).
3. A receiving method for multimedia multicast in a wireless communication system, comprising:
(a) receiving a signal;
(b) pre-processing the received signal in order to make it the received signal ready for decoding;
(c) decoding a basic message using a noncoherent or a coherent Unitary Space-time decoding scheme; and
(d) delaying a result of step (b) by T symbol periods;
(e) delaying a result of step (c) by T symbol periods;
(f) decoding an additional message using a differential transmission space-time decoding scheme as a function of results of steps (b), (c), (d) and (e).
4. The method according to claim 3 , wherein step (c) satisfies a subsequent equation:
B
^
p
(
k
)
=
arg
max
B
l
∈
Ω
B
tr
{
Y
+
(
k
)
(
B
p
)
l
(
B
p
)
l
+
Y
(
k
)
}
while (f) satisfies the following equation,
D
^
q
(
k
)
=
arg
min
A
ql
∈
Ω
A
B
^
p
+
(
k
)
Y
(
k
)
-
(
A
q
)
l
B
^
p
+
(
k
-
1
)
Y
(
k
-
1
)
where
Y is a result of step (b), {circumflex over (B)} p is a result of step (c), Bp belongs to a basic message set, {circumflex over (D)} q is a result of step (f) and Aq belongs to an additional message set.
5. A transmitting device for multimedia multicast in a wireless communication system, comprising:
a basic message encoder for encoding a basic message using Unitary Space-time coding scheme;
at least one additional message for encoding an additional message using a multiple-antenna differential transmission space-time coding scheme;
delay means for delaying an output of the additional message decoder by T symbol periods;
at least one operational device for combining the output of the basic message encoder, the output of the additional message encoder and the output of the delay means by multiplication and addition;
a post processor for processing a combined signal output from said operational device in order to make a combined signal ready for transmitting; and
multiple transmitter antennas through which a signal output from said post processor is transmitted.
6. The transmitting device according to claim 5 , wherein said operational device satisfies a subsequent equation:
S ( k )= √{square root over (T)}B p ( k ) D q ( k ), k= 1,2, . . .
where
Bp is an output of the basic message encoder, Dq is an output of the additional message encoder, and S is an output of the operational device.
7. A receiving device for multimedia multicast in a wireless communication system, comprising:
a receiver antenna for receiving a signal;
a pre-processor for processing the received signal from the receiver antenna in order to make it ready for decoding;
a basic message decoder for decoding a basic message out of the received signal processed by the pre-processor using a noncoherent or a coherent Unitary Space-time decoding scheme;
delay means for respectively delaying the received signal processed by the pre-processor and the basic message decoded by the basic message decoder by T symbol periods; and
at least one additional message decoder for decoding an additional message based on inputs from the received signal processed by the pre-processor, the basic message decoded by the basic message decoder, the delayed received signal from the delay means and the delayed basic message from the delay means, said additional message decoder using a differential transmission space-time decoding scheme.
8. The receiving device according to claim 7 , wherein said basic message decoder satisfies a subsequent equation:
B
^
p
(
k
)
=
arg
max
B
l
∈
Ω
B
tr
{
Y
+
(
k
)
(
B
p
)
l
(
B
p
)
l
+
Y
(
k
)
}
while said additional message decoder satisfies the following equation,
D
^
q
(
k
)
=
arg
min
A
q
l
∈
Ω
A
B
^
p
+
(
k
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Y
(
k
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-
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A
q
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l
B
^
p
+
(
k
-
1
)
Y
(
k
-
1
)
where
Y is an output of the pre-processor, {circumflex over (B)} p is an output of the basic message decoder, Bp belongs to a basic message set, {circumflex over (D)} q is an output of the additional message decoder and Aq belongs to an additional message set.