Subway and building internal service system by dedicated channel in CDMA mobile phone system

摘要

The present invention relates to an overlay base station by a dedicated channel in a CDMA mobile telephone system and a service system for subways and buildings, and a conventional CDMA mobile telephone system is shaded according to a lack of base station signals in a service area according to a base station height and power limitation. There may be a region, and there may be a region of poor propagation due to interference between the same frequencies. In addition, there may be an area where it is difficult to introduce radio waves from the outside, such as subways and large buildings. In addition, CDMA repeaters are installed and operated in areas where it is difficult to receive radio waves from the outside such as subways and large buildings. The current CDMA repeaters are designed to use the same frequency as the frequency resources used on the ground. This is limited. Therefore, when the CDMA frequency is expanded on the ground, the repeater input power value of the individual frequencies should be set to be low and operated, which causes the call quality of the area serviced by the repeater to be degraded. In addition, even if the number of subscribers on the ground increases, frequency interference increases, resulting in a decrease in call quality in the area where the repeater serves. In addition, the CDMA signal propagation from the repeater to the mobile station affects the base station, resulting in deterioration of the call quality to the subscribers on the ground.;Accordingly, the present invention can set the dedicated CDMA frequency and use this as the operating frequency of the overlay base station, so that the overlay base station can be operated in the CDMA system, thereby eliminating the shadow area due to the lack of other base station signals in the service area. In addition, by using the frequencies transmitted through the overlay base station and the base station using the dedicated frequency as the service dedicated frequency of the repeater installed in the subway and the building, it is possible to solve the difficulties of the expansion of the ground frequency and the interference of the ground wave and repeater service areas. And by eliminating the influence on the base station of the repeater, the call quality is increased.