Research ArticleData compression in wireless sensors network using MDCT and embedded harmonic coding

- The harmonic nature of vibration signals is discussed.
- The Modified Discrete Cosine Transform, as a transform coding scheme is discussed.
- Embedded Harmonic Components Coding is presented to further compress the MDCT coefficients.
- The proposed scheme is fast and suitable for the tiny resources of the wireless nodes.
- The proposed encoding scheme is more efficient than other schemes.

One of the major applications of wireless sensors networks (WSNs) is vibration measurement for the purpose of structural health monitoring and machinery fault diagnosis. WSNs have many advantages over the wired networks such as low cost and reduced setup time. However, the useful bandwidth is limited, as compared to wired networks, resulting in relatively low sampling. One solution to this problem is data compression which, in addition to enhancing sampling rate, saves valuable power of the wireless nodes. In this work, a data compression scheme, based on Modified Discrete Cosine Transform (MDCT) followed by Embedded Harmonic Components Coding (EHCC) is proposed to compress vibration signals. The EHCC is applied to exploit harmonic redundancy present is most vibration signals resulting in improved compression ratio. This scheme is made suitable for the tiny hardware of wireless nodes and it is proved to be fast and effective. The efficiency of the proposed scheme is investigated by conducting several experimental tests.