Second moment adaptation of quadrature amplitude modulation in Coded OFDM over fading channel

Nor K. Noordin, Borhanuddin M. Ali, S. S. Jamuar, Tharek A. Rahman, Mahamod Ismail

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In this paper, we investigate adaptive QAM in Coded OFDM using second moment adaptation of channel SNR. In this scheme the transmitted data is adaptively mapped to M-QAM constellation after a 1/4; rate channel coding, based on the channel state information. The second central moment of the channel impulse response SNR, or its variance, is used as switching thresholds for QAM modulation. With the assumption of perfect channel knowledge, variance of each subband is calculated and compared with the switching thresholds to determine the number of bits per symbol that can be transmitted The 512 subcarriers of this coded OFDM system is divided into 32 subbands so that adaptation is done on a subband basiss. Results show that for adaptation up to 4 bits per symbols, second moment adaptation is about 3 dB more superior than adaptation by mean channel SNR. Comparison has also been made between results of second moment adaptation with fixed 2-, 4- and 8-QAM modulation which shows that BER performance is better (eg. by as much as 10 db compared to 8QAM) with some compensation on throughput.

Original languageEnglish
Title of host publicationIEEE Region 10 Annual International Conference, Proceedings/TENCON
VolumeB
Publication statusPublished - 2004
EventIEEE TENCON 2004 - 2004 IEEE Region 10 Conference: Analog and Digital Techniques in Electrical Engineering - Chiang Mai
Duration: 21 Nov 200424 Nov 2004

Other

OtherIEEE TENCON 2004 - 2004 IEEE Region 10 Conference: Analog and Digital Techniques in Electrical Engineering
CityChiang Mai
Period21/11/0424/11/04

Fingerprint

Quadrature amplitude modulation
Fading channels
Orthogonal frequency division multiplexing
Modulation
Channel coding
Channel state information
Impulse response
Throughput

ASJC Scopus subject areas

  • Engineering(all)

Cite this

Noordin, N. K., Ali, B. M., Jamuar, S. S., Rahman, T. A., & Ismail, M. (2004). Second moment adaptation of quadrature amplitude modulation in Coded OFDM over fading channel. In IEEE Region 10 Annual International Conference, Proceedings/TENCON (Vol. B)

Second moment adaptation of quadrature amplitude modulation in Coded OFDM over fading channel. / Noordin, Nor K.; Ali, Borhanuddin M.; Jamuar, S. S.; Rahman, Tharek A.; Ismail, Mahamod.

IEEE Region 10 Annual International Conference, Proceedings/TENCON. Vol. B 2004.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Noordin, NK, Ali, BM, Jamuar, SS, Rahman, TA & Ismail, M 2004, Second moment adaptation of quadrature amplitude modulation in Coded OFDM over fading channel. in IEEE Region 10 Annual International Conference, Proceedings/TENCON. vol. B, IEEE TENCON 2004 - 2004 IEEE Region 10 Conference: Analog and Digital Techniques in Electrical Engineering, Chiang Mai, 21/11/04.
Noordin NK, Ali BM, Jamuar SS, Rahman TA, Ismail M. Second moment adaptation of quadrature amplitude modulation in Coded OFDM over fading channel. In IEEE Region 10 Annual International Conference, Proceedings/TENCON. Vol. B. 2004
Noordin, Nor K. ; Ali, Borhanuddin M. ; Jamuar, S. S. ; Rahman, Tharek A. ; Ismail, Mahamod. / Second moment adaptation of quadrature amplitude modulation in Coded OFDM over fading channel. IEEE Region 10 Annual International Conference, Proceedings/TENCON. Vol. B 2004.
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