Solving Interference Issues in Mobile Signal Blocking Systems with Base Station Time Division Duplex (TDD) Synchronization Technology

Mobile signal blocking systems have become increasingly diverse in the market today, with the majority of products utilizing wideband white noise power suppression. However, many of these shielding devices have inadvertently caused interference with surrounding mobile base stations, particularly affecting the uplink signals. Fortunately, resolving this interference issue is not difficult and can be achieved by incorporating base station time division duplex (TDD) synchronization technology into specific frequency bands. This article explores the frequencies that require TDD synchronization in order to avoid interfering with base stations.

Frequency Bands and TDD Synchronization:

The frequency bands that require TDD synchronization are those that adopt time division duplexing for mobile communication, while others employ frequency division duplexing, strictly separating the uplink and downlink frequency ranges. Taking the GSM900 frequency band as an example, the uplink frequency range is 885-915MHz, exclusively used for uplink signal transmission. The downlink frequency range is 930-960MHz, solely dedicated to downlink signal transmission. These two frequency bands do not overlap, ensuring independent data communication. Another example is the TD-SCDMA frequency band, which operates within the 2010-2025MHz range with a total bandwidth of 15MHz. Due to the implementation of time division duplexing, both uplink and downlink data are transmitted within this bandwidth, but divided by time. In other words, a specific time period is allocated for uplink data transmission, followed by a separate time period for downlink data transmission.

Implementing TDD Synchronization in Mobile Signal Blocking Systems:

To prevent interference with base stations, mobile signal blocking systems need to incorporate TDD synchronization for the relevant frequency bands. By synchronizing the time division duplexing frequency bands, the signal blocking module designed for time division duplexing can emit interference signals during the base station’s processing of downlink signals. Conversely, when the base station handles uplink data, the corresponding frequency band in the mobile signal blocking system ceases operation.

Frequencies Requiring TDD Synchronization:

Currently, there are five frequency bands utilized by various network operators that employ TDD technology. These include China Mobile’s 1885-1915MHz, 2010-2025MHz, and 2515-2675MHz, as well as the indoor micro base station signal amplification frequency of 2300MHz, and China Telecom and China Unicom’s 3.5GHz.


In conclusion, by equipping mobile signal blocking systems with base station time division duplex synchronization technology for these five frequency bands, interference with base station uplink signals can be completely avoided. This solution ensures the effective operation of both mobile signal blocking systems and base stations, enabling uninterrupted communication for users.