Point to point wireless audio with limited bandwidth and processing

Abstract

This project investigates the possibility of implementing a point-to-point wireless audio transmission system for real-time operation on a specific embedded platform. The platform is originally intended for wireless PC peripherals such as keyboards and mouses and uses a proprietary radio module for transmission. The report accompanying the project can be used as a guide for doing a similar project on other platforms. The report is organized as follows. Properties of the platform are presented, and an assessment on what how it can perform in terms of computational power is carried out. ADPCM is chosen as a compression scheme and its underlying theory is briefly presented. As the platform does not do native floating point operations, fixed point number representation and operations are discussed. Error concealment for packet transmission is briefly discussed. An assessment on the performance of the on-chip analog-to-digital converter is carried out and an approach to implementing a 1-bit digital-to-analog converter using pulse-width modulation is discussed. Implementation issues when designing a real-time audio communication system are discussed. Performance tests are carried out, and finally a set of real-world applications for the system are presented. The project finds that a point-to-point wireless audio transmission system for half-duplex, real-time operation is possible for the given platform. Because of radio limitations, full-duplex operation is yet to be proven as possible. A project exists that investigates the radio module for the same platform in details. For confidentiality, the name of the platform is not referenced.