Directional transmission by 3-D beam-forming using smart antenna arrays

Beam forming is a widely used antenna technique to adjust the radiation beam towards one direction, which is quite useful for interference alignment, and overcome multiple access interference, common channel interference as well as multi path fading, thus increases the capacity of mobile networks. Thus fixed antenna array can be configured to be smart antenna with the help of digital signal processing technique. However, all the conventional 2-D beam forming is implemented by a fixed vertical angle of in the Spherical coordinates, while only consider the beam pattern on cylindrical coordinates. As the trend of modern communication, where the femto cell is proposed for the future base station, directional transmission is reconsidered in terms of better coverage and better frequency reuse. In order to have maximum transmission efficiency as well as minimal interference, a 3-D beam is necessary. This paper presents a 3-D beam forming technique that can be used for high direction al transmission.