Modeling a Multicarrier Wireless Communication Transceiver Embedded Software Systems Literature Survey March 24,2004 By Hunaid Lotia

Overview Multicarrier Modulation Multicarrier Modulation Motivation Motivation Existing Research Existing Research OFDM (Orthogonal Frequency Division Multiplexing) OFDM (Orthogonal Frequency Division Multiplexing) Goals Goals Questions Questions

Multicarrier Modulation Technique in which multiple frequencies are used to transmit data Technique in which multiple frequencies are used to transmit data Divide broadband channel into narrowband sub channels Divide broadband channel into narrowband sub channels Widely used in ADSL and wireless LAN Widely used in ADSL and wireless LAN

Motivation for Multicarrier Modulation Applications requiring high rate data transmission. Applications requiring high rate data transmission. Increasing power of Digital Signal Processing tools. (1960’s) Increasing power of Digital Signal Processing tools. (1960’s) Applications range from Digital Audio and Video Broadcasting to High-Speed Wireless LANs. Applications range from Digital Audio and Video Broadcasting to High-Speed Wireless LANs.

Existing Work and Research Most common candidates for Multicarrier Wireless (Mobile) Communication are: Most common candidates for Multicarrier Wireless (Mobile) Communication are: Direct Sequence Code Division Multiple Access (DS-CDMA)- Receiver Complexity Direct Sequence Code Division Multiple Access (DS-CDMA)- Receiver Complexity Frequency Hopping-CDMA (FH-CDMA)- Requires powerful channel coding to mitigate fading effects. Frequency Hopping-CDMA (FH-CDMA)- Requires powerful channel coding to mitigate fading effects. Solution: OFDM Transmission System Solution: OFDM Transmission System –Considered for fourth-generation mobile communication systems.

P/S QAM decoder invert channel = frequency domain equalizer S/P quadrature amplitude modulation (QAM) encoder N - length Inverse FFT add cyclic prefix P/S D/A + transmit filter N -length FFT S/P remove cyclic prefix TRANSMITTER RECEIVER N subchannelsN complex samples N subchannels Receive filter + A/D multipath channel An OFDM Modem Bits

Project Goals Model the OFDM system in Synchronous Dataflow (SDF) Model the OFDM system in Synchronous Dataflow (SDF) –All nodes produce and consume fixed number of tokens –Use SDF domain in Ptolemy to verify the model –Investigate other open issues that come up as the projects builds up

QUESTIONS? QUESTIONS?