In-band on-channel digital broadcasting method and system

A method of receiving an in-band on-channel (IBOC) digital broadcast radio frequency (RF) signal via a receiver comprising the steps of:

• receiving the IBOC digital signal having redundant source bit information in both an upper and a lower sideband relative to a center frequency, wherein the redundant source bit information in the upper sideband is differently represented than the corresponding redundant source bit information in the corresponding lower sideband so that spectrums of the upper and lower sidebands including the redundant source bit information are not mirrored relative to one another about the center frequency;
• determining, in the receiver, whether the source bit information in the redundantly modulated upper sideband or the lower sideband is less likely to contain source bit errors;
• and
• selecting, in the receiver, the source bit information determined in said determining step to be less likely to contain errors, so that the method of receiving is robust against adjacent channel interference.

An in-band on-channel (IBOC) digital audio broadcast (DAB) communication system including a transmitter and at least one receiver, the IBOC DAB system comprising:

• a transmitter including an analog FM signal generator, an upper sideband digital signal generator, and a lower sideband digital signal generator, said transmitter for combining an analog FM signal generated by said FM signal generator together with digital sideband signals from said upper and lower sideband generators into a composite signal to be transmitted wherein said sideband signals each include source bit information;
• said upper sideband generator performing a first encoding and said lower sideband generator performing a different second encoding so that redundant source bit information is transmitted in the upper and lower sidebands with the upper sideband being differently encoded than the lower sideband having the corresponding redundant source bit information;
• means for transmitting said composite signal including the upper and lower sidebands;
• an IBOC DAB receiver for receiving said composite signal, said receiver including an FM analog demodulator, an upper sideband digital demodulator, and a lower sideband digital demodulator;
• said receiver further including a comparing device for determining which of (i) recovered source bit information from demodulation of the upper sideband IBOC DAB signal, and (ii) recovered source bit information from demodulation of the lower sideband IBOC DAB signal, is less likely to be erroneous;
• and
• said receiver further including a selector for selecting for further processing and forwarding to a user the demodulated or recovered source bit information from sideband signals determined by said comparing device to be less likely to include source bit errors.