Implementation of OFDM acoustic modem using TMS320VC5416

Author

Lapsirisward, Thanawit ; Nakpeerayuth, Suvit

Author_Institution

Dept. of Electr. Eng., Chulalongkorn Univ., Bangkok, Thailand

fYear

2013

fDate

15-17 May 2013

Firstpage

1

Lastpage

5

Abstract

This paper presents the design and implementation result of a real-time acoustic OFDM modem transmitted over the air using TMS320VC5416 DSP. The system uses PC speaker and vocal dynamic microphone as the transducers. The sampling frequency is 48 kHz with 128 sub-carriers using 256 points FFT. The system uses selective mapping method (SLM) as PAPR reduction technique to reduce the signal clipping and ABPL techniques to equalize the received CNR on all sub-carriers so that the symbol error probability are also equalized. The test results show that these techniques are working as expected. The Eb/No curve are close to QAM64 even if the channel are severely distorted. The system can transmit at 66250 bits/sec with bit error rate 1.0×10-5 at Eb/No 16.72 dB. The system has not included the carrier synchronization yet. This will be the future work.

Keywords

OFDM modulation; acoustic signal processing; digital signal processing chips; error statistics; fast Fourier transforms; microphones; modems; quadrature amplitude modulation; signal sampling; ABPL techniques; Eb-No curve; FFT; PAPR reduction technique; PC speaker; QAM64; SLM; TMS320VC5416 DSP; bit error rate; fast Fourier transform; frequency 48 kHz; noise figure 16.72 dB; real-time acoustic OFDM modem; sampling frequency; selective mapping method; signal clipping reduction; symbol error probability; vocal dynamic microphone; Acoustics; Digital signal processing; Equalizers; Modems; Peak to average power ratio; Phase shift keying; ABPL; DSP; OFDM; PAPR; real-time;

fLanguage

English

Publisher

ieee

Conference_Titel

Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology (ECTI-CON), 2013 10th International Conference on

Conference_Location

Krabi

Print_ISBN

978-1-4799-0546-1

Type

conf

DOI

10.1109/ECTICon.2013.6559649

Filename

6559649