Junita Mohd Nordin

Mitigation of multiple access interference using two-dimensional modified double weight codes for optical code division multiple access systems

We proposed newly two-dimensional (2- D ) spectral amplitude coding optical code division multiple access (OCDMA) scheme using modified double weight (MDW) code capable of suppressing phase-induced intensity noise (PIIN). The architecture of the spectral/spatial MDW OCDMA system with the property of multi-access interference cancellation is presented. The proposed code exhibits good cross-correlation property. At the optimized data transmission rate of 0.745 Gbps, 2-D MDW, M = 63, N = 3, reaches maximum cardinality of 200% increases compared to 2- D perfect difference code, M = 57, N = 3. The performance is severely deteriorated if the data rate further increases above 0.745 Gbps. The proposed code meets the optical transmission requirements at 10−9 bit error rate error floor, with lowest effective transmitted power ( P sr), −17.5  dBm, in comparison to the others through minimizing interference noise that result in PIIN suppression. The proposed system reaches optimum requirements performance in terms of cardinality, data transmission rate, and low effective transmitted power.

A review of techniques design acoustic energy harvesting

This paper presents a study of recent development in the field of acoustic energy harvesters (AEHs) technique and the maximum power generated from each of these techniques. AEHs convert the acoustic energy into useful electrical energy for the operation of autonomous wireless sensors. Acoustic energy is an important form of efficiency energy which is created and unused all around us. Due to the majority of acoustic energy a main challenge of energy harvesting is the low power density in typical acoustic noise fields. With a superior emphasis on green energy, acoustic energy is one of the enormously existing energy sources and so harvesting this energy plays an significant role in research. Since acoustic energy is environmentally friendly and sufficient to replace as disadvantages of conventional battery which have limited lifespan and problematic in electronics could expire at any time and replacement of the battery causing some cost and time. The induced acoustic wave can be transformed into electricity by presenting novel environment friendly energy converters.