The Structure and Generation of Robust Waveforms ... - iBiquity Digital

format. Each matrix consists of information from
whole or partial logical channels and is
associated with a specific portion of the
transmitted spectrum. Diversity delay is also
imposed on selected logical channels. It is
through this function that the time redundancy of
logical channel P1, in service modes MA1 and
MA3, is created.
System Control Processing. This function
generates a vector of system control data
sequences that includes system control
information received from layer 2 (such as
service mode and configuration options), and
status for broadcast on the reference subcarriers.
This information is used at the receiver to
determine how to process the AM IBOC system
waveforms.
OFDM Subcarrier Mapping. This function
assigns the interleaver matrices and system
control vector to OFDM subcarriers. One row of
each active interleaver matrix and one bit of the
system control vector is processed each OFDM
symbol to produce one output vector X, which is
a frequency domain representation of the signal.
OFDM Signal Generation. This function
generates the digital portion of the time-domain
AM IBOC waveform. The input vectors X are
transformed into a shaped time-domain baseband
pulse, y n (t), defining one OFDM symbol.
Transmission Subsystem. This function formats
the baseband waveform for transmission through
the MF channel. Major sub-functions include,
symbol concatenation, and frequency upconversion.
When transmitting a hybrid
waveform, this function modulates the AM
analog audio source and coherently combines it
with the digital signal to form a composite
hybrid signal, s(t), ready for transmission.
ACKNOWLEDGEMENTS
The author would like to acknowledge the
following people for their contributions to the
development of iBiquity Digital’s AM IBOC
digital broadcasting system: Dr. Brian Kroeger,
Glynn Walden, Rick Martinson, Anjali Shastri,
Joe Bronder, Ed Dickens, and Jim Fisch.
signals,“ Bell sys. Tech. J., vol. 45, pp. 1775-
1796 Dec. 1966.
[3] S.B. Weinstein and P.M. Ebert, “Data
transmission by frequency-division multiplexing
using the discrete Fourier transform,” IEEE
Trans. on Comm. Tech., vol. COM-19, pp. 628-
634, Oct. 1971.
[4] B.R. Saltzberg, “Performance of an efficient
parallel data transmission system,” IEEE Trans.
on Comm. Tech., vol. COM-15, pp. 805-811,
Dec. 1967.
[5] Federal Communications Commission, Code
of Federal Regulations, Title 47, Part 73
[6] “Petition for Rulemaking to the United States
Federal Communications Commission for In-
Band On-Channel Digital Audio Broadcasting,”
Appendix C, p. 7, USA Digital Radio
Corporation, October 7, 1998
REFERENCES
[1] ISO 7498, “Open Systems Interconnection
(OSI) Basic Reference Model.”
[2] R.W. Chang, “High-speed multichannel data
transmission with bandlimited orthogonal
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