Orthogonal Sub-Carrier Mapping for Low Latency Wireless Audio
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Solution Overview
Problem
Existing in-ear-monitor systems face challenges with spectral inefficiency, user scalability, and high latency due to analog systems, which require dedicated frequency sub-bands and are not efficiently user scalable.
Innovation Solution
The system employs a digital approach with transmitters and receivers configured to use orthogonal sub-carrier spacing in the frequency-time domain, allowing for efficient spectrum use and scalability by mapping audio channels to sub-carriers in a narrow bandwidth, enabling low latency audio playback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If analog systems are used with dedicated frequency sub-bands for each receiver, then audio transmission reliability is improved, but spectral efficiency deteriorates and user scalability is limited
Solution Approach 1:
The frequency spectrum is segmented into multiple orthogonal sub-carriers that can be dynamically allocated to different receivers. Instead of dedicating entire sub-bands to each receiver, the system divides the spectrum into finer granular sub-carriers that can be shared and reallocated based on user needs, improving both spectral efficiency and scalability while maintaining reliable transmission through orthogonal frequency division multiplexing
Solution Approach 2:
The system implements dynamic sub-carrier allocation where receivers can be reassigned to different frequency sub-carriers in real-time based on channel conditions and user requirements. This dynamic approach replaces the static dedicated sub-band allocation of analog systems, enabling efficient spectrum utilization and user scalability without compromising transmission reliability through adaptive resource management
2Adaptability or versatility
If analog systems allocate additional sub-bands for additional users, then user scalability is improved, but bandwidth consumption increases
Solution Approach 1:
The orthogonal sub-carrier system serves multiple users within the same bandwidth by enabling each sub-carrier to be dynamically assigned to different receivers based on demand. This universal allocation mechanism allows the same frequency resources to serve multiple users at different times, achieving user scalability without proportionally increasing bandwidth consumption
Solution Approach 2:
The system adds the time dimension to frequency allocation by implementing time-varying sub-carrier assignments. Instead of static frequency allocation, receivers can access different sub-carriers at different time intervals, creating a time-frequency resource matrix that supports multiple users within the same bandwidth through orthogonal frequency-division multiple access
3Device complexity
If analog systems are used for wireless audio transmission, then implementation simplicity is improved, but latency increases and exceeds 20 ms
Solution Approach 1:
The system replaces analog mechanical/electrical signal processing with digital signal processing for audio transmission. Digital modulation and demodulation of orthogonal sub-carriers enable precise control and faster processing compared to analog systems, reducing transmission latency below 20 ms while maintaining implementation feasibility through standardized digital communication protocols
Data Source
AI summary
Described are systems, methods, apparatuses, and computer program products for wireless in-ear-monitoring (IEM) of audio. A system includes transmitter(s) configured to map orthogonal sub-carriers of a digital signal to narrowband receivers to form receiver-allocated audio channels, modulate the digital signal, and transmit the signal as an ultra-high frequency (UHF) analog carrier wave comprising the orthogonal sub-carriers to the nearby receiver. A narrowband receiver is configured to demodulate and sample the sub-carriers allocated to the receiver. Sub-carriers can be positioned orthogonal to one another in adjacent sub-bands of the frequency domain and beacon symbols and pilot signals can be iteratively provided in the same portion of the frequency domain for each channel. The receiver can use non-data-aided and data-aided approaches for synchronization of the time domain and frequency domain waveforms of the received signal to the transmitted signal prior to sampling the allocated sub-carriers.