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Application of Smart Antenna Technology in 3G
Jul 03, 2017

In WCDMA and CDMA2000 applications. The third generation system is designed as a system that can provide fairly high speed data services. However, they will also be subject to air channel quality as the 2nd generation system. Standardization organizations have recognized the role of smart antennas in improving this paradox and have developed relevant provisions in the 3G standard. Both WCDMA and CDMA2000 allow the assignment of dedicated pilot channels for each mobile subscriber on the uplink and downlink, but will require the use of smart antenna systems.

For WCDMA and CDMA2000 systems, although the smart antenna is recommended configuration, but some of today's WCDMA and CDMA2000 base station products have begun to support the smart antenna.

Can antenna technology

Application in TD - SCDMA System. The high efficiency of the TDSCDMA (Time Division Synchronous Code Division Multiple Access) smart antenna is obtained based on the symmetry of the uplink and downlink wireless paths (wireless environment and transmission conditions are the same). In addition, the smart antenna can reduce inter-cell interference, but also reduce the interference within the district. These features of the smart antenna can significantly improve the spectral efficiency of mobile communication systems.

The smart antenna of the TD-SCDMA system consists of a concentric array of 8 antenna elements with a diameter of 25 cm. Compared with omni-directional antenna, it can get higher gain. The principle is to make a group of antennas and the corresponding transceiver in a certain way to arrange and encourage the use of wave interference principle can produce a strong direction of the radiation pattern, the use of DSP (digital signal processor) to make the main lobe adaptive Point to the direction of the mobile station, you can achieve to improve the signal load-bearing ratio, reduce the transmission power and other purposes. The above performance of smart antennas allows for more intensive frequency reuse, resulting in a significant increase in spectral efficiency.

Since each user's location within the cell is different. This aspect requires that the antenna has a multi-directional, on the other hand requires that in each independent direction, the system can track individual users. The above requirements can be achieved by controlling the direction of the user by the DSP. Each user's tracking is measured by the angle of arrival. In the TD-SCDMA system, since the length of the radio subframe is 5 ms, it can be measured at least 200 times per second, and the uplink and downlink transmission of each user takes place in the same direction. Through the orientation and tracking of the smart antenna, Best performance.

A further advantage of TD-SCDMA in TDD (Time Division Duplex) mode is that both the transmission and reception of user signals occur at exactly the same frequency. So the transmission conditions in both upstream and downstream directions are the same or symmetrical, allowing the smart antenna to minimize inter-cell interference to achieve optimal system performance.