Abstract: A system and method for switching master and slave roles of devices for use in wireless communications. The method includes: establishing a monitoring link for communications between a master device and a host device; and initiating a role exchange request, in which a time point for role exchange is appointed, by the master device or a slave device via the monitoring link when role switching between the master device and the slave device is triggered, and replying with a request receipt acknowledgment packet for the receipt of the role exchange request by the other device via the monitoring link. The system includes the master device, the slave device, and the host device, wherein the master device includes a master processing module; and the slave device includes a slave processing module. The role exchange between the master device and the slave device keeps energy consumptions of the two devices evened out.

Abstract: A system and a method for defrosting/de-icing an air-conditioner are provided, the system comprising: a 3D depth sensor disposed inside an air-conditioner outdoor unit casing, for acquiring information regarding outer diameters of pipes of an outdoor heat exchanger, distances between the pipes, and distances between the respective pipes and an air-conditioner outdoor unit casing side plate; and a controller connected to the 3D depth sensor, for receiving the information acquired by the 3D depth sensor and controlling the air conditioner to enter or exit a defrosting-deicing mode. The system and method for defrosting/de-icing an air-conditioner provided by the present disclosure can effectively and timely perform defrost/de-ice operation on the outdoor heat exchanger to prevent freezing; besides, it can prevent the impact on the air-conditioner's heating function to the utmost extent so as to significantly improve user experience.

Abstract: Disclosed is a method for low voltage broadband power line carrier communication; when transmitting a physical layer protocol frame, short preambles are first transmitted to undergo automatic gain control, channel estimation, coarse-grained frequency offset compensation, and symbol synchronization; and then long preambles are transmitted to undergo automatic gain control, channel estimation, fine-grained frequency offset compensation, and symbol synchronization. Compared with the scheme of only transmitting long preambles, the present disclosure combines transmissions of short preambles and long preambles, which thus may quickly and accurately implement frequency offset compensation, automatic gain control, symbol synchronization, and channel estimation without sacrifice of precision, thereby achieving quick convergence, reducing resource overheads and time overheads, and enhancing system performance.

Abstract: Disclosed is a method for spreading data symbol frequency domain information in power line carrier communication, wherein when generating a data symbol in power line carrier communication, multiple times of frequency domain information diversity copy is used in place of the conventional ROBO copy, such that the diversity copy is independent of channel time-varying property, but only dependent on channel characteristics; as such, diversity copy is implemented within the same symbol, which facilitates simplifying the processing circuit of frequency domain and meanwhile enhances communication reliability.