A Simple Access Point Synchronization for THz Wireless Access System

In order to fulfill the demand of increasing data transmission rate, usage of THz band is attracting much attention. To overcome the high propagation loss in THz band, access points (APs) are supposed to be densely placed. In order to control radio resource usage of APs as well as supporting applications that require device positioning, it is highly desirable that symbol timings of the APs are synchronized. In this paper, as an alternative approach to use a synchronization master, network synchronization nor the synchronization using global navigation satellite system (GNSS), over-the-air (OTA) peer AP synchronization is proposed, where a pair of peer APs adjusts their symbol timings according to measured time of arrival (ToA) of each other's signal. By performing the peer AP synchronization with other surrounding peer APs, a whole group of APs can form a synchronized cluster. The results of computer simulations show that the maximum symbol timing difference of APs can be kept less than 10 ps for the case that the symbol duration is 100 ps, with which centimeter level device positioning can be supported.