invented at Telia Research in Luleå.7 With
this technique, adjacent subcarriers carry
data in opposite directions (Figure 6). However,
requirements for spectral compatibility
with existing DSL technologies necessitate
that several tones must be grouped into
transmission bands. One can preserve the orthogonallity
between the received signal
and the transmitted signal echoed back into
the receiver by cyclically extending the
transmitted DMT symbols using a cyclic
prefix and cyclic suffix and by synchronizing
the transmitters at each end to begin
transmitting at the same time (a technique
called timing advance). Cyclic extension,
which eliminates intersymbol interference
(ISI) caused by the channel, reduces the data
rate by 7.8%. Windowing, a technique for
suppressing side lobes, further reduces spectral
leakage between transmission bands.
Windowing is also used in OFDM (Figure 7).
invented at Telia Research in Luleå.7 With
this technique, adjacent subcarriers carry
data in opposite directions (Figure 6). However,
requirements for spectral compatibility
with existing DSL technologies necessitate
that several tones must be grouped into
transmission bands. One can preserve the orthogonallity
between the received signal
and the transmitted signal echoed back into
the receiver by cyclically extending the
transmitted DMT symbols using a cyclic
prefix and cyclic suffix and by synchronizing
the transmitters at each end to begin
transmitting at the same time (a technique
called timing advance). Cyclic extension,
which eliminates intersymbol interference
(ISI) caused by the channel, reduces the data
rate by 7.8%. Windowing, a technique for
suppressing side lobes, further reduces spectral
leakage between transmission bands.
Windowing is also used in OFDM (Figure 7).
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