Closed loop multiple-antenna wireless communications system with antenna weights determined by maximizing a composite channel signal-to-interference-plus-noise ratio minimum. The RF power amplification module may further include a directional coupler coupled with the RF power amplifier and configured to produce a power signal at a coupling port of the directional coupler corresponding to an output power of the RF power amplifier. The interconnect assembly further includes a thermal management layer disposed within a portion of the encapsulant and proximate to the plurality of electronic die and a controlled impedance interconnect connected to the interconnect structure and extending to a peripheral surface of the interconnect assembly. The SIM-card-detection module is used for detecting whether the first SIM card is replaced by a second SIM card and generating a corresponding detection result. After that water is let to ingress into the well and the underwater section is lowered down by the auxiliary lift to dock bottom or sea bed, from where the underwater section is picked up with a crane.