TY - JOUR
T1 - Adaptive OFDMA with partial CSI for downlink underwater acoustic communications
AU - Zhang, Yuzhi
AU - Huang, Yi
AU - Wan, Lei
AU - Zhou, Shengli
AU - Shen, Xiaohong
AU - Wang, Haiyan
N1 - Publisher Copyright:
© 2011 KICS.
PY - 2016/6
Y1 - 2016/6
N2 - Multiuser communication has been an important research area of underwater acoustic communications and networking. This paper studies the use of adaptive orthogonal frequencydivision multiple access (OFDMA) in a downlink scenario, where a central node sends data to multiple distributed nodes simultaneously. In practical implementations, the instantaneous channel state information (CSI) cannot be perfectly known by the central node in time-varying underwater acoustic (UWA) channels, due to the long propagation delays resulting from the low sound speed. In this paper, we explore the CSI feedback for resource allocation. An adaptive power-bit loading algorithm is presented, which assigns subcarriers to different users and allocates power and bits to each subcarrier, aiming to minimize the bit error rate (BER) under power and throughput constraints. Simulation results show considerable performance gains due to adaptive subcarrier allocation and further improvement through power and bit loading, as compared to the non-adaptive interleave subcarrier allocation scheme. In a lake experiment, channel feedback reduction is implemented through subcarrier clustering and uniform quantization. Although the performance gains are not as large as expected, experiment results confirm that adaptive subcarrier allocation schemes based on delayed channel feedback or long term statistics outperform the interleave subcarrier allocation scheme.
AB - Multiuser communication has been an important research area of underwater acoustic communications and networking. This paper studies the use of adaptive orthogonal frequencydivision multiple access (OFDMA) in a downlink scenario, where a central node sends data to multiple distributed nodes simultaneously. In practical implementations, the instantaneous channel state information (CSI) cannot be perfectly known by the central node in time-varying underwater acoustic (UWA) channels, due to the long propagation delays resulting from the low sound speed. In this paper, we explore the CSI feedback for resource allocation. An adaptive power-bit loading algorithm is presented, which assigns subcarriers to different users and allocates power and bits to each subcarrier, aiming to minimize the bit error rate (BER) under power and throughput constraints. Simulation results show considerable performance gains due to adaptive subcarrier allocation and further improvement through power and bit loading, as compared to the non-adaptive interleave subcarrier allocation scheme. In a lake experiment, channel feedback reduction is implemented through subcarrier clustering and uniform quantization. Although the performance gains are not as large as expected, experiment results confirm that adaptive subcarrier allocation schemes based on delayed channel feedback or long term statistics outperform the interleave subcarrier allocation scheme.
KW - Orthogonal frequency-division multiple access(OFDMA)
KW - outdated channel state information
KW - power and bit loading
KW - subcarrier allocation
KW - underwater acoustic communications
UR - http://www.scopus.com/inward/record.url?scp=84990237912&partnerID=8YFLogxK
U2 - 10.1109/JCN.2016.000054
DO - 10.1109/JCN.2016.000054
M3 - 文章
AN - SCOPUS:84990237912
SN - 1229-2370
VL - 18
SP - 387
EP - 396
JO - Journal of Communications and Networks
JF - Journal of Communications and Networks
IS - 3
M1 - 7575805
ER -