Wireless communication system and wireless slave and master units used therein

Abstract

A wireless communication system wherein the higher the priority level of an information signal to be transmitted by a slave unit, such as an operating switch, is, the shorter the time period (t1) of a carrier sense to be performed before the transmission of the information signal is caused to be. In this way, even when slave units are about to transmit information signals of mutually different priority levels by use of the same time slot, one of the slave units being about to transmit an information signal having the higher priority level than any other slave unit is allowed to cause the time period (t1) of a carrier sense, which is to be performed before the transmission of the information signal, to be shorter than any other slave unit, so that the one slave unit can transmit the information signal earliest. Thus, the slave unit that becomes able to transmit the information signal earliest is caused to transmit the information signal, thereby allowing the information signal having the highest priority level to be transmitted earliest, while causing each of the other units to detect that transmission by use of the carrier sense, thereby causing the other unit to defer the transmission of the information signal.

Description

technical field [0001] The present invention relates to a wireless communication system that transmits information signals from a wireless slave unit to a wireless master unit using radio waves, and a wireless slave unit and a wireless master unit used in the wireless communication system. Background technique [0002] Conventionally, a radio communication system is known in which a plurality of radio slave units transmit various information signals to a radio master unit in a slotted ALOHA (Slotted ALOHA) manner using a carrier of the same frequency. In this wireless communication system, a wireless slave unit transmits an information signal in an arbitrary time slot in synchronization with time slots obtained by dividing time at fixed intervals. When the wireless handset transmits information signals, in order to avoid interference between its own radio waves and radio waves from other radios, it performs carrier sense to check whether radio waves are sent from other radio...

AI Technical Summary

Problems solved by technology

[0011] However, the signal sent from the wireless master unit is prone to jitter due to the influence of the transmission environment, and the timing to reach the wireless slave unit may be delayed from the regular timing.

In the wireless handset as described in Patent Document 1, since the timing error is corrected using the reception timing of the signal, it is difficult to perform high-precision correction, resulting in reduced timing accuracy.

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