IBOC Audio Packet Switching With Sequence Alignment
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Solution Overview
Problem
In IBOC digital radio broadcasting systems, the switch between main program audio and emergency alert audio disrupts the orderly progression of sequence numbers, leading to disjoint audio decoding and silence interruptions in digital radio receivers.
Innovation Solution
An IBOC digital radio broadcasting system aligns sequence numbers of emergency alert audio packets with main program audio packets before switching, ensuring a seamless transition by maintaining the order of sequence numbers during switchover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the system switches between main program audio and emergency alert audio packets on the same logical channel, then emergency alert audio can be broadcasted, but the sequence numbers become disjoint and disorderly causing decoding failures
Solution Approach 1:
The patent applies preliminary action by pre-establishing sequence number alignment rules before switching between audio sources. The system prepares the sequence number mapping and ordering structure in advance, so when switching from main program audio to emergency alert audio, the sequence numbers are already configured to progress orderly without disruption to the decoding process.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a sequence number alignment layer that sits between the packet switching logic and the audio decoder. This intermediary reorders and renumbers packets to maintain continuous sequence progression, acting as a mediator that translates the discontinuous packet source into a continuous sequence stream for the decoder.
2Adaptability or versatility
If the digital radio receiver switches audio sources, then emergency alert audio can be played, but the decoding process cannot recover audio seamlessly due to sequence number disruption
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the sequence number parameter during audio source switching. Instead of maintaining fixed sequence numbering, the system modifies the sequence number assignment to reflect the new audio source while preserving the continuous progression property, allowing the decoder to operate seamlessly across source transitions.
Solution Approach 2:
The receiver performs preliminary action by pre-configuring the sequence number alignment rules and buffer management strategies before switching occurs. This preparation ensures that when the switch to emergency alert audio happens, the decoding process can continue without interruption because the necessary structural adjustments are already in place.
3Productivity
If sequence numbers are not aligned during switchover, then emergency alert audio can be transmitted, but disjoint audio is presented to the listener with silence interruptions
Solution Approach 1:
The patent implements continuity of useful action by ensuring that the sequence number progression continues uninterrupted during the switch from main program audio to emergency alert audio. The system maintains the continuous sequence numbering invariant, allowing the audio decoder to operate without stopping or resetting, thus preserving audio continuity and preventing silence interruptions while still enabling efficient emergency alert transmission.
Solution Approach 2:
The sequence alignment mechanism acts as an intermediary that buffers and reorders packets during the transition. This intermediary layer absorbs the discontinuity introduced by switching packet sources and presents a continuous, properly sequenced stream to the decoder, preventing information loss and maintaining audio integrity throughout the emergency alert transmission.
Data Source
AI summary
A method performed by at an importer-exporter of an it1-band on-channel (IBOC) digital radio broadcasting system comprises: receiving, from a first audio client, first protocol data units (PDUs) (first PDUs) of encoded main audio and that include first sequence numbers that progress in a first order; sending the first PDUs for transmission over a logical channel of an IBOC waveform; receiving, from a second audio client, second PDUs of encoded non-main audio and that include second sequence numbers; aligning the second PDUs to the first PDUs by aligning the second sequence numbers to the fust sequence numbers, to produce aligned second PDUs; and switching to sending the aligned second PDUs for transmission over the logical channel in place of the first PDUs such that the second sequence numbers of the aligned second PDUs after switching maintain the first order of the first sequence numbers as established prior to switching.