| Summary |
A CDMA unslotted ALOHA system is a connectionless-type of CDMA packet
communication system.
In this system, a user station can transmit a packet
asynchronously and randomly, and so the packet birth/death event is
one of the most important problems for multiuser detection.
We have proposed the CDMA unslotted ALOHA system using an adaptive filter
receiver based on minimum mean square error criterion in [8],
and shown the improvement in the throughput performance
even considering the effect of birth/death event.
The ensemble-averaged squared error, however, increases at the point
of packet birth.
In this paper, we employ interleaving and forward error correction (FEC)
coding techniques to mitigate the momentary increase in ensemble-averaged
squared error.
The use of FEC, however, causes the increase in MAI due to redundancy bits
of FEC. Moreover, signal power is reduced under the condition that the
energy of an information bit is the same. In such cases,
whether an adaptive filter can operate effectively or not interests us.
We evaluate the system performance and show that the improvement in
throughput is achieved with interleaving and FEC techniques.
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