<s>
Vector	B-Algorithm
sum	I-Algorithm
excited	I-Algorithm
linear	I-Algorithm
prediction	I-Algorithm
(	O
VSELP	O
)	O
is	O
a	O
speech	B-Application
coding	I-Application
method	O
used	O
in	O
several	O
cellular	O
standards	O
.	O
</s>
<s>
The	O
VSELP	O
algorithm	O
is	O
an	O
analysis-by-synthesis	B-Application
coding	O
technique	O
and	O
belongs	O
to	O
the	O
class	O
of	O
speech	B-Application
coding	I-Application
algorithms	O
known	O
as	O
CELP	B-Algorithm
(	O
Code	B-Algorithm
Excited	I-Algorithm
Linear	I-Algorithm
Prediction	I-Algorithm
)	O
.	O
</s>
<s>
Variations	O
of	O
this	O
codec	B-General_Concept
have	O
been	O
used	O
in	O
several	O
2G	O
cellular	O
telephony	O
standards	O
,	O
including	O
IS-54	O
,	O
IS-136	O
(	O
D-AMPS	O
)	O
,	O
GSM	O
(	O
Half	B-Algorithm
Rate	I-Algorithm
speech	O
)	O
and	O
iDEN	O
.	O
</s>
<s>
It	O
was	O
also	O
used	O
in	O
the	O
first	O
version	O
of	O
RealAudio	B-Algorithm
for	O
audio	O
over	O
the	O
Internet	O
.	O
</s>
<s>
In	O
an	O
actual	O
TDMA	O
cell	O
phone	O
,	O
the	O
vocoder	B-Application
output	O
is	O
packaged	O
with	O
error	O
correction	O
and	O
signaling	O
information	O
,	O
resulting	O
in	O
an	O
over-the-air	O
data	O
rate	O
of	O
16.2	O
kbit/s	O
.	O
</s>
<s>
GSM	O
half-rate	O
VSELP	O
(	O
GSM	B-Algorithm
06.20	I-Algorithm
)	O
uses	O
20	O
ms	O
frames	O
with	O
112	O
bits	O
per	O
frame	O
,	O
giving	O
a	O
raw	O
data	O
rate	O
of	O
5.6	O
kbit/s	O
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
use	O
of	O
VSELP	O
has	O
been	O
gradually	O
phased	O
out	O
in	O
favor	O
of	O
newer	O
codecs	B-General_Concept
.	O
</s>
