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Abstract(s)
A DS-CDMA (Direct Sequence-Coded Division Multiple
Access) system has maximum spectral efficiency if the
system is fully loaded (i.e., the number of users is equal to the
spreading factor) and we employ signals with bandwidth equal
to the chip rate. However, due to implementation constraints we
need to employ signals with higher bandwidth, decreasing the
system’s spectral efficiency. In this paper we consider prefixassisted
DS-CDMA systems with bandwidth that can be significantly
above the chip rate. To allow high spectral efficiency we
consider highly overloaded systems where the number of users
can be twice the spreading factor or even more. To cope with
the strong interference levels we present an iterative frequencydomain
receiver that takes full advantage of the total bandwidth
of the transmitted signals. Our performance results show that the
proposed receiver can have excellent performance, even for highly
overloaded systems. Moreover, the overall system performance
can be close to the maximum theoretical spectral efficiency, even
with transmitted signals that have bandwidth significantly above
the chip rate.
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Networking and broadcasting Communication Devices and systems Components Circuits Computing and processing (Hardware/ software)