Time division duplex (TDD)

Time division duplex ( TDD ) brief introduction

Is a kind of communication system of duplex mode, in a mobile communication system for transmitting and receiving channel separation. The third generation mobile communication is currently developing, China in 1997 June submitted a draft of third generation mobile communication standard ( TD-SCDMA ), the TDD model and intelligent antenna technology characteristics have been highly valued and into three main candidate standard of. In the first generation and the second generation mobile communication system of FDD model in TDD mode rule all the land, no attention. But because of new business needs and development of new technologies, as well as the TDD model of many advantages, TDD mode will have received increasing attention.

Due to the growth of mobile data service, personal communication and broadband requirement, mobile communication is develops to the third generation, estimated at the beginning of twenty-first Century ( 2002) of third generation mobile communication system will start a full commercial. Review of the one or two generation mobile communication system construction in China, almost 100% rely on imports of foreign products. Now the situation has been different. In 1997 June, China submitted to the third generation mobile communication standard draft ( TD-SCDMA ), the TDD model and intelligent antenna technology characteristics have been highly valued and became one of the three main candidate standard of TD-SCDMA mobile communication system, and base station equipment is stepping up development.

Time division duplex ( TDD ).

TDD is a kind of communication system for duplex mode, in the mobile communication system for the separation of receiving and transmitting channel ( or downlink ). TDD mode in a mobile communication system for receiving and transmitting at the same frequency channel carrier different time slot, with guaranteed time to separate the receiving and transmitting channel; and FDD mode mobile communication system which receives and transmits in the separation of the two symmetrical frequency channel, use the band to separate receiving and transmitting channel.

Using different duplex modes of mobile communication system and communication efficiency is different. TDD mode mobile communication system uplink and downlink channels using the same frequency, thus having uplink and downlink channel reciprocity, this gives TDD mode mobile communication system offers many advantages.