A BER-Conscious Synthesis of Switched-Beam Antenna to Maximize Reliable Coverage in WSN Applications

Abstract

A BER-conscious synthesis of switched multi-beam multi-sector access point (AP) antenna is proposed to enhance reliable communication coverage for WSN applications. The sector-based design of multi-beam AP antenna is necessary for a densely deployed WSN to achieve high system capacity with 360° azimuth coverage. However, the neighboring sectors cause high co-channel interference resulting in a low signal to interference (SIR) ratio and hence degrades the communication link quality. This leads to frequent packet re-transmissions resulting in increased energy consumption at the power deficient sensor nodes. The proposed BER-conscious array synthesis scheme incorporates projected power and SIR limits within the antenna design process to maximize the effective coverage area with acceptable BER. The optimized coverage with reliable communication implies energy saving at the sensor nodes. Based on the proposed process of coverage optimization, a multi-sector AP antenna is analytically synthesized. A prototype is fabricated, and the analytically obtained coverage results are verified through experiments. The maximum radial range of 2 – 13 m with 360° communication coverage is achieved. Moreover, high port isolation of 45.95 dB between adjacent sectors enables the generation of multiple simultaneous beams in the communication region resulting in high system capacity. The achieved performance indicates that the synthesized switched multi-beam multi-sector antenna using the proposed scheme is a good candidate for AP in WSN applications.