<s>
Carrier	B-General_Concept
aggregation	I-General_Concept
is	O
a	O
technique	O
that	O
is	O
used	O
in	O
wireless	O
communication	O
to	O
increase	O
the	O
data	O
rate	O
per	O
user	O
,	O
whereby	O
multiple	O
frequency	O
blocks	O
(	O
called	O
component	O
carriers	O
)	O
are	O
assigned	O
to	O
the	O
same	O
user	O
.	O
</s>
<s>
In	O
addition	O
load	O
balancing	O
is	O
possible	O
with	O
carrier	B-General_Concept
aggregation	I-General_Concept
.	O
</s>
<s>
Depending	O
on	O
the	O
positions	O
of	O
the	O
component	O
carriers	O
three	O
cases	O
of	O
carrier	B-General_Concept
aggregation	I-General_Concept
are	O
distinguished	O
:	O
</s>
<s>
The	O
case	O
where	O
the	O
component	O
carriers	O
are	O
contiguous	O
in	O
the	O
same	O
frequency	O
band	O
is	O
called	O
intra-band	O
contiguous	O
carrier	B-General_Concept
aggregation	I-General_Concept
.	O
</s>
<s>
If	O
the	O
component	O
carriers	O
are	O
in	O
the	O
same	O
frequency	O
band	O
but	O
are	O
separated	O
by	O
a	O
gap	O
the	O
carrier	B-General_Concept
aggregation	I-General_Concept
is	O
called	O
intra-band	O
non-contiguous	O
.	O
</s>
<s>
This	O
is	O
called	O
inter-band	O
carrier	B-General_Concept
aggregation	I-General_Concept
applied	O
to	O
heterogeneous	O
networks	O
.	O
</s>
<s>
However	O
,	O
the	O
complexity	O
from	O
an	O
RF	O
point	O
of	O
view	O
is	O
increased	O
in	O
the	O
case	O
inter-band	O
carrier	B-General_Concept
aggregation	I-General_Concept
.	O
</s>
<s>
The	O
channel	O
bandwidth	O
for	O
UMTS/HSPA	O
+	O
is	O
about	O
3.8MHz	O
with	O
a	O
carrier	O
spacing	O
of	O
5MHz	O
.	O
</s>
<s>
Carrier	B-General_Concept
aggregation	I-General_Concept
is	O
also	O
called	O
Dual	O
Cell	O
in	O
the	O
context	O
of	O
UMTS/HSPA	O
+	O
.	O
</s>
<s>
Through	O
carrier	B-General_Concept
aggregation	I-General_Concept
(	O
part	O
of	O
the	O
UMTS	B-Protocol
extension	O
HSPA+	O
)	O
two	O
downlink	O
carriers	O
may	O
be	O
assigned	O
to	O
one	O
user	O
since	O
Release8	O
.	O
</s>
<s>
3GPP	O
standardized	O
carrier	B-General_Concept
aggregation	I-General_Concept
for	O
HSPA+	O
for	O
the	O
uplink	B-Application
for	O
up	O
to	O
two	O
component	O
carriers	O
since	O
Release9	O
.	O
</s>
<s>
A	O
difference	O
between	O
two	O
aggregated	O
10MHz	O
component	O
carriers	O
and	O
a	O
single	O
ordinary	O
20MHz	O
channel	O
is	O
that	O
in	O
the	O
case	O
of	O
carrier	B-General_Concept
aggregation	I-General_Concept
the	O
control	O
information	O
is	O
transmitted	O
on	O
both	O
component	O
carriers	O
.	O
</s>
<s>
LTE	O
Advanced	O
with	O
carrier	B-General_Concept
aggregation	I-General_Concept
allows	O
Gigabit	O
LTE	O
.	O
</s>
<s>
This	O
is	O
made	O
possible	O
through	O
higher-order	O
modulation	O
(	O
256QAM	O
)	O
,	O
carrier	B-General_Concept
aggregation	I-General_Concept
and	O
4x4MIMO	O
.	O
</s>
