Multi-Carrier Digital Communications: Theory and Applications of Ofdm
Multi-Carrier Digital Communications: Theory and Applications of Ofdm
Wireless OFDM Systems: How to Make Them Work?
Wireless OFDM Systems: How to Make Them Work?
FOCS '02 Proceedings of the 43rd Symposium on Foundations of Computer Science
Fundamentals of wireless communication
Fundamentals of wireless communication
IEEE/ACM Transactions on Networking (TON) - Special issue on networking and information theory
A Parallel Hardware Architecture for fast Gaussian Elimination over GF(2)
FCCM '06 Proceedings of the 14th Annual IEEE Symposium on Field-Programmable Custom Computing Machines
Introduction to Probability Models, Ninth Edition
Introduction to Probability Models, Ninth Edition
OFDM-Based Broadband Wireless Networks: Design and Optimization
OFDM-Based Broadband Wireless Networks: Design and Optimization
Low-density parity-check codes based on finite geometries: a rediscovery and new results
IEEE Transactions on Information Theory
A comparison of the HIPERLAN/2 and IEEE 802.11a wireless LAN standards
IEEE Communications Magazine
Practical evaluation of opportunistic error correction
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
Energy efficient error correction in mobile TV
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
Hi-index | 0.00 |
We propose a novel cross layer scheme to reduce the power consumption of ADCs in OFDM systems. The ADCs in a receiver can consume up to 50% of the total baseband energy. Our scheme is based on resolution-adaptive ADCs and Fountain codes. In a wireless frequency-selective channel some subcarriers have good channel conditions and others are attenuated. The key part of the proposed system is that the dynamic range of ADCs can be reduced by discarding subcarriers that are attenuated by the channel. Correspondingly, the power consumption in ADCs can be decreased. In our approach, each subcarrier carries a Fountain-encoded packet. To protect Fountain-encoded packets against bit errors, an LDPC code has been used. The receiver only decodes subcarriers (i.e., Fountain-encoded packets) with the highest SNR. Others are discarded. For that reason a LDPC code with a relatively high code rate can be used. The new error correction layer does not require perfect channel knowledge, so it can be used in a realistic system where the channel is estimated. With our approach, more than 70% of the energy consumption in the ADCs can be saved compared with the conventional IEEE 802.11a WLAN system under the same channel conditions and throughput. In addition, it requires 7.5 dB less SNR than the 802.11a system. To reduce the overhead of Fountain codes, we apply message passing and Gaussian elimination in the decoder. In this way, the overhead is 3% for a small block size (i.e., 500 packets). Using both methods results in an efficient system with low delay.