<s>
Enhanced	B-Algorithm
Variable	I-Algorithm
Rate	I-Algorithm
Codec	I-Algorithm
B	I-Algorithm
(	O
EVRC-B	B-Algorithm
)	O
is	O
a	O
speech	O
codec	O
used	O
by	O
CDMA	B-Protocol
networks	O
.	O
</s>
<s>
In	O
addition	O
,	O
there	O
are	O
two	O
zero	O
bit	O
codec	O
frame	O
types	O
:	O
null	O
frames	O
and	O
erasure	O
frames	O
,	O
similar	O
to	O
EVRC	B-Algorithm
.	O
</s>
<s>
One	O
significant	O
enhancement	O
in	O
EVRC-B	B-Algorithm
is	O
the	O
use	O
of	O
1/4	O
rate	O
frames	O
that	O
were	O
not	O
used	O
in	O
EVRC	B-Algorithm
.	O
</s>
<s>
This	O
provides	O
lower	O
average	O
data	O
rates	O
(	O
ADRs	O
)	O
compared	O
to	O
EVRC	B-Algorithm
,	O
for	O
a	O
given	O
voice	O
quality	O
.	O
</s>
<s>
The	O
new	O
4GV	O
Codecs	O
used	O
in	O
CDMA2000	O
are	O
based	O
on	O
EVRC-B	B-Algorithm
.	O
</s>
<s>
The	O
Enhanced	B-Algorithm
Variable	I-Algorithm
Rate	I-Algorithm
Coder	I-Algorithm
(	O
EVRC	B-Algorithm
)	O
is	O
a	O
speech	O
codec	O
used	O
for	O
cellular	O
telephony	O
in	O
cdma2000	O
systems	O
.	O
</s>
<s>
EVRC	B-Algorithm
provides	O
excellent	O
speech	O
quality	O
using	O
variable	O
rate	O
coding	O
with	O
3	O
possible	O
rates	O
,	O
8.55	O
,	O
4.0	O
and	O
0.8	O
kbit/s	O
.	O
</s>
<s>
However	O
,	O
the	O
Quality	O
of	O
Service	O
(	O
QoS	O
)	O
in	O
cdma2000	O
systems	O
can	O
significantly	O
benefit	O
from	O
a	O
codec	O
which	O
allows	O
tradeoffs	O
between	O
voice	O
quality	O
and	O
network	O
capacity	O
,	O
which	O
cannot	O
be	O
achieved	O
efficiently	O
with	O
the	O
EVRC	B-Algorithm
.	O
</s>
<s>
An	O
upgrade	O
of	O
the	O
EVRC	B-Algorithm
vocoder	B-Application
,	O
known	O
as	O
EVRC-B	B-Algorithm
,	O
was	O
recently	O
introduced	O
by	O
3GPP2	O
.	O
</s>
<s>
The	O
EVRC-B	B-Algorithm
speech	O
codec	O
is	O
based	O
on	O
the	O
4GV	O
concept	O
and	O
is	O
the	O
newest	O
and	O
most	O
advanced	O
speech	O
codec	O
for	O
cellular	O
applications	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
Relaxed	O
Code	O
Excitation	O
Linear	O
Prediction	O
(	O
RCELP	O
)	O
used	O
by	O
EVRC	B-Algorithm
,	O
EVRC-B	B-Algorithm
uses	O
Prototype	O
Pitch	O
Period	O
(	O
PPP	O
)	O
approach	O
for	O
coding	O
of	O
stationary	O
voice	O
frames	O
and	O
Noise	O
Excitation	O
Linear	O
Prediction	O
(	O
NELP	O
)	O
for	O
efficient	O
coding	O
of	O
unvoiced	O
or	O
noise	O
frames	O
.	O
</s>
<s>
Using	O
NELP	O
and	O
PPP	O
coding	O
at	O
2.0	O
kbit/s	O
provides	O
EVRC-B	B-Algorithm
with	O
superior	O
flexibility	O
in	O
rate	O
assignment	O
,	O
allowing	O
it	O
to	O
operate	O
at	O
several	O
operating	O
points	O
,	O
each	O
with	O
a	O
different	O
trade-off	O
between	O
speech	O
quality	O
and	O
system	O
capacity	O
.	O
</s>
<s>
EVRC-B	B-Algorithm
replaced	O
EVRC	B-Algorithm
as	O
the	O
main	O
speech	O
codec	O
for	O
cdma2000	O
and	O
its	O
first	O
network	O
commercial	O
deployment	O
started	O
in	O
2007	O
.	O
</s>
<s>
A	O
wideband	O
extension	O
,	O
EVRC-WB	O
,	O
provides	O
speech	O
quality	O
that	O
exceeds	O
regular	O
wireline	O
telephony	O
and	O
its	O
standardization	O
process	O
was	O
completed	O
at	O
the	O
summer	O
of	O
2007	O
.	O
</s>
<s>
EVRC-WB	O
uses	O
a	O
modified	O
discrete	O
cosine	O
transform	O
(	O
MDCT	O
)	O
audio	O
coding	O
algorithm	O
.	O
</s>
<s>
EVRC-B	B-Algorithm
can	O
be	O
also	O
used	O
in	O
3GPP2	O
container	O
file	O
format	O
-	O
3G2	O
.	O
</s>
