Demonstration of V-band 1  <b>×</b>  3 SIMO long-distance millimeter-wave wireless transmission over 1.2 km employing MRC technology

This paper presents the implementation of a photonics-assisted V-band 1<b> </b>×<b> </b>3 single-input multiple-output (SIMO) millimeter-wave wireless transmission system, achieving a transmission distance of 1.2<b> </b>km. The system utilizes a dual-laser beating technique to generate a high-purity millimeter-wave carrier and incorporates offline digital signal processing (DSP) algorithms-including down-conversion, resampling, combination of Constant Modulus Algorithm (CMA) equalization and a Fractionally Spaced Equalizer (FSE), block phase search (BPS), and maximal ratio combining (MRC)-to achieve signal fusion and performance optimization among multiple receiving branches. Experimental results demonstrate that after maximal ratio combining, the signal's signal-to-noise ratio (SNR) is improved by approximately 5 dB, and the bit error rate (BER) is reduced by an order of magnitude, with the constellation diagram showing significant convergence, thereby enabling stable transmission without the use of forward error correction (FEC). To the best of our knowledge, this is the first experimental demonstration of high-gain performance achieved using these techniques in a V-band 1<b> </b>×<b> </b>3 SIMO millimeter-wave system.