Decode-and-forward relaying based on orthogonal complementary codes
Kizilirmak, Refik Caglar
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Abstract
In this note, we propose a full-duplex decode-and-forward cooperative
diversity scheme based on code division with orthogonal complementary
codes. We consider a simple case in which a single user is assisted by a
single relay to achieve cooperative diversity. When the cooperation is
full-duplex, the operational delay of the relay makes the channel
asynchronous and this may cause multiple-access interference (MAI)
between the user and relay. The orthogonal complementary codes have
perfect autocorrrelation and cross-correlation properties that provide
MAI-free operation in asynchronous channels. In the proposed scheme, the
user and relay terminals spread their messages with complementary codes
and the spread messages can reach the destination without interfering
with each other. The numerical results reveal that the proposed scheme
reaches the same bit-error-rate performance in both synchronous and
asynchronous channels. The results are also compared with the
conventional orthogonal code sets, such as Hadamard sets, which fail to
provide diversity.... Show more Show less