Date：Apr.12th 2019
Address：ZhengZhang Building, ShenYun Interchange, ShaHe Construction Village, LongZhu Avenue, NanShan District, ShenZhen City.
Requests：China Mobile and Chine Unicom communication signal coverage of the negative layer of ZhengZhang Building
1．The Surrounding Survey
1. ZhengZhang Building is located in NanShan District of Shenzhen City, which has great base station coverage and high quality signal strength.
2. There is a Telecom base station on the top of the building, so the signal strength of Telecom on the negative ground floor is good enough. The base stations of China Mobile and China Unicom are hundreds of meters away from the building, which could be used as signal sources.
3. , On the roof, we checked the communication signal frequency of China Mobile is DCS1800MHZ, signal strength -63db, and communication signal frequency of China Unicom is WCDMA2100MHZ, signal stregnth -57db. Signal strength both of them are quite good.
4. The environmental survey of negative layer. It’s the place to dry-cleaning and store the clothes. There are many workers but no a mobile signal to guarantee the communication.
In some compartments, China mobile signal frequency can’t be detected; try to call 10086 (China Mobile’s service hotline), but no answer. Out of service for China Unicom.
2．Solution
No any layout of the negative ground floor. According to the estimated area of the site is about 800 square meters, and two aisles around the corner. We manually drew the layout and offer solution of antennas’ location as belows.
According to the layout, we have a complete solution as below. As the negative ground floor is empty, the coverage of each antenna could be guaranteed. Due to the length of the cable, FB-12 cables would be adopted to ensure its perfect performance of each antenna.
High power dual band booster DCS1800+WCDMA2100 would be used, its full output power is +23dbm.
3． Construction of cables.
4．Efficiency
The output power of China Mobile (1800Mhz) & China Unicom (2100Mhz) reach +25dbm and +24dbm, which performs to the full output power perfectly. Refer to below pictures.
Within the three scopes with 5 ceiling antennas, the signal strength is over -85dbm, the calling quality and speed achieves great effectiveness. Below shows the random test of signal strength: China Mobile -63dbm, China Unicom -67dbm, both of them are full bar.
5．Conclusion
The case- Signal Coverage Solution of ZhengZhang building negative ground floor is very typical with negative ground floor Characteristics: nice signal strength on the roof, no any signal in the negative ground floor, too long wiring construction, few suitable local of antennas. Adopting high power dual band booster and 1/2 RF cables could achieve great output effect and application experience.