Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Channel coding increases the achievable rate of the cognitive networks
AU - Mokari, Nader
AU - Saeedi, Hamid
AU - Navaie, Keivan
PY - 2013/3
Y1 - 2013/3
N2 - In this letter, we investigate employing Trellis Coded Modulation (TCM) in an Orthogonal Frequency Division Multiple Access (OFDMA) based secondary system in an underlay cognitive radio network. While it is expectable for channel coding to improve the performance in the secondary service compared to the uncoded case at the expense of rate reduction, our results indicate that the benefits of such utilization is beyond expectation. In fact we show that for a given bandwidth and bit error rate performance, the coded scheme not only requires less average transmit power per subcarrier, but it also provides a significantly higher sum-rate compared to the uncoded case. This result is against the well-known property of channel coding in conventional communication systems where we sacrifice effective date rate to reduce the required power for a given bit error rate. This is due to the fact that using TCM in the secondary system, we successfully transmit bits with a lower transmit power. Having a transmission with lower transmit power, we would be able to transmit with a higher bit rate in the secondary system and still meet the interference threshold requirements in the primary network. Total rate is increased if the increase due to lower transmit power beats the decrease caused by coding. Our simulation results show that this is indeed the case for TCM-OFDMA secondary system.
AB - In this letter, we investigate employing Trellis Coded Modulation (TCM) in an Orthogonal Frequency Division Multiple Access (OFDMA) based secondary system in an underlay cognitive radio network. While it is expectable for channel coding to improve the performance in the secondary service compared to the uncoded case at the expense of rate reduction, our results indicate that the benefits of such utilization is beyond expectation. In fact we show that for a given bandwidth and bit error rate performance, the coded scheme not only requires less average transmit power per subcarrier, but it also provides a significantly higher sum-rate compared to the uncoded case. This result is against the well-known property of channel coding in conventional communication systems where we sacrifice effective date rate to reduce the required power for a given bit error rate. This is due to the fact that using TCM in the secondary system, we successfully transmit bits with a lower transmit power. Having a transmission with lower transmit power, we would be able to transmit with a higher bit rate in the secondary system and still meet the interference threshold requirements in the primary network. Total rate is increased if the increase due to lower transmit power beats the decrease caused by coding. Our simulation results show that this is indeed the case for TCM-OFDMA secondary system.
KW - Cognitive networks
KW - coding design
KW - trellis coded modulation
KW - OFDMA
KW - RADIO NETWORKS
KW - SPECTRUM
KW - ACCESS
U2 - 10.1109/LCOMM.2013.012313.122437
DO - 10.1109/LCOMM.2013.012313.122437
M3 - Journal article
VL - 17
SP - 495
EP - 498
JO - IEEE Communications Letters
JF - IEEE Communications Letters
SN - 1089-7798
IS - 3
ER -