从智能天线的工作原理出发说明使用智能天线时很难实现小区的分扇区应用、多频点天线公

用,因此可以证明智能天线还不是一项可供商用的实用技术 考虑相邻小区/扇区时隙的不对称分

配所产生的相邻小区/扇区收发干扰时,可以证明上、下行时隙实质上是不能按需分配的。3 G使

用的频段是2 GHz,具有传播衰落大、穿透能力差、不易做大范围覆盖。TD2SCDMA标准很难提供3

G标准所规定的在车载、步行、静止环境下分别达到144 kbit/ s、384 kbit/ s和2 048 kbit/ s的无线接

入速率要求。-It is p resented in the paper that it is difficult to realize the sectored cell and the same antenna for

multip le frequency channels by analyzing the theory of the smart antenna. Therefore it can be p roved that the smart

antenna technology is not a commercial technology at p resent. Asymmetry slot distribution between inter2cells/ sec2

torswould bring the transmission and receiving interference between the inter2cells/ sectors, so it can’t be put into

p ractical app lication. The technological defects of the TD2SCDMA standard are analyzed in the paper from many as2

pects, such as the characteristics of 2 GHz frequency band,MS’s transmission power, a cell capacity on up link /

downlink and so on. TD2SCDMA system is difficult to support different radio access data rates, such as vehicular

environment: 144 kbit/ s, pedestrian environment: 384 kbit/ s, indoor office environment: 2. 048 Mbit/ s, which

are required by 3G standards