TY - GEN
T1 - Selected subcarriers QPSK-OFDM transmission schemes to combat frequency disturbances
AU - Papilaya, Victor N.
AU - Shongwe, Thokozani
AU - Vinck, A. J.Han
AU - Ferreira, Hendrik C.
PY - 2012
Y1 - 2012
N2 - To combat the impairments caused by frequency disturbances in the power line communications (PLC), a modified conventional QPSK-OFDM transmission scheme is presented. The idea of this scheme is to first group the N OFDM subcarriers into groups of and then transmit data by selecting a subset of the subcarriers in the group. Real and imaginary parts of QPSK symbols are independently assigned to the selected subcarriers in a group, such that the minimum squared Euclidean distance is maximised. With this kind of symbol assignment to subcarriers our scheme has no net loss in terms of SNR requirements, in AWGN, in comparison to the conventional QPSK-OFDM, even though it has half the data rate of the conventional QPSK-OFDM. We refer to the conventional QPSK-OFDM as Scheme A. Our scheme displays a superior performance over Scheme A and another scheme (Scheme B), in the presence of frequency disturbances and also frequency selective fading noise. We further modify Scheme B and come up with additional two new QPSK-OFDM schemes that have better performance than Scheme B in AWGN and impulse noise. To encode, we apply a (n, k) RS code and a simple permutation code on the conventional QPSK-OFDM scheme, which significantly improves the decoder's performance in the presence of frequency disturbances. A simple narrow band noise model is developed and presented.
AB - To combat the impairments caused by frequency disturbances in the power line communications (PLC), a modified conventional QPSK-OFDM transmission scheme is presented. The idea of this scheme is to first group the N OFDM subcarriers into groups of and then transmit data by selecting a subset of the subcarriers in the group. Real and imaginary parts of QPSK symbols are independently assigned to the selected subcarriers in a group, such that the minimum squared Euclidean distance is maximised. With this kind of symbol assignment to subcarriers our scheme has no net loss in terms of SNR requirements, in AWGN, in comparison to the conventional QPSK-OFDM, even though it has half the data rate of the conventional QPSK-OFDM. We refer to the conventional QPSK-OFDM as Scheme A. Our scheme displays a superior performance over Scheme A and another scheme (Scheme B), in the presence of frequency disturbances and also frequency selective fading noise. We further modify Scheme B and come up with additional two new QPSK-OFDM schemes that have better performance than Scheme B in AWGN and impulse noise. To encode, we apply a (n, k) RS code and a simple permutation code on the conventional QPSK-OFDM scheme, which significantly improves the decoder's performance in the presence of frequency disturbances. A simple narrow band noise model is developed and presented.
KW - QPSK-OFDM
KW - Selected subcarriers
KW - concatenated RS-Permutation codes
KW - frequency disturbances
KW - narrow band noise model
UR - http://www.scopus.com/inward/record.url?scp=84861969767&partnerID=8YFLogxK
U2 - 10.1109/ISPLC.2012.6201327
DO - 10.1109/ISPLC.2012.6201327
M3 - Conference contribution
AN - SCOPUS:84861969767
SN - 9781467303590
T3 - 2012 IEEE International Symposium on Power Line Communications and Its Applications, ISPLC 2012
SP - 200
EP - 205
BT - 2012 IEEE International Symposium on Power Line Communications and Its Applications, ISPLC 2012
T2 - 2012 16th IEEE International Symposium on Power Line Communications and Its Applications, ISPLC 2012
Y2 - 27 March 2012 through 30 March 2012
ER -