Space Division Duplex (SDD) system using smart antenna

Abstract

The most important property in wireless systems, when it comes to increasing spectral efficiency, is eliminating interference. Recently, there are several new multiple access schemes and duplexing systems have been introduced in wireless systems to overcome several major interferences such as inter symbol interference, multiple access interference and adjacent cell interference. In this paper, we introduce a new duplexing system so-called space division duplex which can eliminate all kinds of interference. This new duplexing system consists of smart antenna's multiple steered narrow beams and orthogonal large area synchronous spread spectrum codes. The purpose is to increase system capacity while maintain its zero correlation window characteristics. The major types of interference and the properties of large area synchronous codes to combat these major interferences are studied. The overviews of code division duplexing system applying these orthogonal smart codes in wireless environment are analyzed. These analyses have shown that the number of orthogonal codes utilization is limited. The proposed solutions of space division duplexing system with several advantages are presented. Besides that, the code reuse concept is proposed to overcome the limitation of orthogonal codes. Finally, the system performances in term of spectral efficiency and capacity are presented. © 2005 IEEE.