Through the performance of comprehensive channel characterizations, conducting countless simulations using real world data and logging over 75,000 hours of over-the-air tests on numerous radio stations, iBiquity Digital designed its IBOC technology to bring the benefits of digital audio broadcasting to today's radio while preventing interference to the "host" analog station and stations on adjacent channels.
These new digital signals are broadcast as "sideband" transmissions bracketing the top and bottom of the current "host" analog signal in order to make optimal usage of the current spectrum allocations. With more than half of stations currently facing interference from adjacent stations, this approach delivers redundant information on both sides of the current channel location in order to ensure optimal performance in all listening environments.
iBiquity Digital's IBOC technology further combats interference through our unique First Adjacent Canceller (FAC) technology. FAC automatically differentiates between the digital sideband transmission and other analog signals that might be closely adjacent to the channel in order to suppress the interfering station.
iBiquity Digital's IBOC technology overcomes multipath interference and sources of noise through the use of proprietary coding and power combining techniques. This proprietary approach to error correction utilizes digital processors and powerful algorithms to constantly compare the quality of the two digital sideband transmissions, combining them to deliver additional power gain whenever possible and when not possible seamlessly switching to the more powerful of the two.
In much the same way that a portable CD player digitally stores a short passage of music in order to overcome any momentary interruptions, the interleaver approach incorporated into IBOC technology further enhances performances. By "caching" or storing the broadcast into short-term memory, the interleaver allows for the uninterrupted transition between analog and digital signal within the same channel in order to avoid the drop off that might occur due to a bridge or other obstruction. In order to deliver instantaneous tuning, the interleaver also seamlessly enables the initial selection of the analog signal and subsequent transition to the digital signal once properly cached. Compression of audio data will increase transmission without losing sound quality.
By employing the above techniques incorporating multiple digital signal techniques, such as redundant sidebands, blend, first adjacent cancellation, and code and power sharing, iBiquity Digital's IBOC technology is designed to capture a superior robust signal within a station's coverage area in order to ensure delivery of the benefits of HD Radio technology.
For even more detailed information, download our white papers:
Conversion Requirements for AM & FM IBOC Transmission
Jeff R. Detweiler, iBiquity Digital Corporation
Abstract: IBOC provides a unique opportunity for broadcasters and consumers to transition from analog to digital broadcasting without service interruption while maintaining the current dial positions of existing radio stations. Consumers who purchase digital radios will receive their favorite AM and FM stations with superior digital quality, free from the static, hiss, pops and fades associated with today's analog radio reception. In addition to offering digital audio quality and crystal clear reception, IBOC offers the broadcaster the lowest entry cost into the wireless data industry. Through careful attention to the equipment decisions made today, broadcasters may significantly reduce the cost of conversion. This paper defines the requirements and guidelines for cost-effective equipment selection for IBOC conversion.
An Advanced Application Services Framework for Application and Service Developers Using HD Radio™ Technology
Abstract: The HD Radio system allows multiple services to share the broadcast capacity of a single station. First generation (core) services include the Main Program Service (MPS) and the Station Information Service (SIS). This paper describes the concepts and foundation for an Advanced Application Services Framework which will provide next generation service and application developers with the application programming interfaces (API) required to rapidly develop, prototype and deploy their capabilities on future generation HD Radio platforms.
IBOC DAB Field Test Platforms
Abstract: In 2001, iBiquity Digital Corporation tested its AM and FM In-Band, On-Channel Digital Audio Broadcasting systems under the auspices of the National Radio Systems Committee. In preparation for this test program, iBiquity developed a new field test platform to meet the NRSC's requirements, as well as, to improve testing performance, user interfaces and post-test analysis tools. This new field-testing platform is described here.
The Structure and Generation of Robust Waveforms for AM In-Band On-Channel Digital Broadcasting
Steven A. Johnson, iBiquity Digital Corporation
Abstract: A robust In-Band On-Channel (IBOC) Digital Broadcasting system for offering improved performance over existing analog AM broadcasting has been completed by iBiquity Digital Corporation. The solution is both forward and backward compatible and does not require the allocation of additional channel spectrum. Broadcasters can simultaneously transmit both analog and digital signals within the allocated channel mask allowing full compatibility with existing analog receivers. The solution also allows broadcasters to transmit an all-digital signal, replacing the hybrid analog/digital signal. This paper focuses on the generation and transmission of the AM IBOC waveform, including a description of the characteristics and features of the system.
The Structure and Generation of Robust Waveforms for FM In-Band On-Channel Digital Broadcasting
Paul J. Peyla, iBiquity Digital Corporation
Abstract: iBiquity Digital Corporation has developed a digital broadcasting solution that permits a smooth evolution from current analog FM radio to a fully digital In-Band On-Channel (IBOC) system. The system delivers digital audio and data services to mobile, portable, and fixed receivers from terrestrial transmitters in the existing VHF radio band. Broadcasters may continue to transmit analog FM simultaneously with the new, higher quality and more robust digital signals. This approach allows broadcasters to convert from analog to digital radio while maintaining their current frequency allocations. This paper describes the structure, generation and inherent flexibility of the transmitted FM IBOC waveforms.
HD Radio™ Data Network Requirements
Timothy Anderson, iBiquity Digital Corporation
Abstract: Minimizing network induced dropouts is a prime consideration for the successful implementation of an HD Radio system. The purpose of this document is to aid the station engineer in the successful integration and connection of various networked components necessary for the implementation of HD Radio Advanced Application Services, specifically Multicasting. Further, this document will provide a frame of reference and understanding to manufacturers, developers, and consultants in refining and fulfilling present and future needs for this critical element of the HD Radio system. This paper is a culmination and summary of the research and experience of iBiquity engineers and our consultants as well as the station engineers in the field.
HD Radio™ Networking Implementation Recommendations
Kurt VanderSluis, MTM Technologies
Abstract: iBiquity Digital contracted the independent data networking firm MTM Technologies to provide specific recommendations for the construction and provisioning of the digital links connecting HD Radio studio facilities and transmitters. This paper summarizes MTM’s recommendations after an exhaustive study of the nature, resiliency and failure modes of the digital transmissions under adverse network conditions in a controlled lab setting as well as field surveys of several radio stations employing iBiquity technology in production settings with varying degrees of success.
HD Radio™ Networking Best Practices
Trieu Vu, MTM Technologies
Abstract: iBiquity Digital contracted the independent data networking firm of MTM Technologies to provide consultation and specific recommendations for the construction network required for the successful implementation of HD Radio technology. This paper is a collection of the findings both in the lab and in the real world. It contains rudimentary definitions of networks devices, their functions and role in a network. More importantly, it also contains recommendations on deployment, location, and proper use of various networking components to ensure the utmost reliability and predictability for an HD Radio network deployment.