1.As the building is far away from the BTS, and plus the shield and sink of the wall, it leads mobile signal blind area.
2.The high level building space is very complex, the BTS signal is not stable, and it is easy to form the signal Ping-Pong switch, easy to drop call and the calling quality is hard to ensure.
3. The elevator and base room are naturally forbidden by the signal.
4. In downtown key area, for the tight building, the BTS can not reach the full coverage, the signal blind and weak area are easily be seen.