Technology Introduction

TDS-OFDM and COFDM respectively are our country ground digital television national standards and the European DVB-T standard core technologies, with belongs to the multi-carrier orthogonal equal division multiplying technology practical application.

TDS-OFDM inserts the synchronized signal in the time domain (time domain channel estimate technology), uses with the pier in the mark joins the pseudo-random sequence which Walshe codes, is lower than 20 decibels the noise to be possible to measure the synchronized signal, may achieve, the fast synchronization reliably like this; Because and has used the time domain channel timating techniques, therefore its synchronizing time compared to the European DVB-T standard quick many; Generally the transmission plan, for example the European DVB-T synchronizing time is about 100 milliseconds, but may achieve in 5 milliseconds based on the Qinghua TDS-OFDM GB code technology, and may carry on the addressing localization accurately, the precision in 10 meters, therefore may expand the honeycomb network.

WiMAX All called World Interoperability for Microwave Access, is the world's Interoperability for Microwave Access, is a standard based on IEEE 802.16 broadband wireless access MAN technology (Broadband Wireless Access Metropolitan Area Network), the standard just developed a physical layer (PHY ) and medium access layer (MAC) specifications, is proposed for the microwave band, a new air interface standards.

The WiMAX elementary object is under the metropolitan area network turning on environment, guaranteed that the different manufacturer the radio equipment rep interconnection intercommunication, mainly uses in for the family, the enterprise as well as the mobile communication network provides “the last kilometer” the high speed broadband access, as well as future individual mobile service.

WiFi Can be a personal computer, handheld device (eg PDA, mobile phones) and other terminal connected to wireless technology. WiFi is a wireless network communication technology, brand, from the Wi-Fi Alliance (Wi-Fi Alliance) held. Objective is to improve the standard based on IEEE 802.11 wireless network interoperability between products. In layman's terms, WiFi is a wireless networking technology, previously adopted by the cable connected to the computer, but now it is networked by radio waves; common is a wireless router, then the wireless router are the effective range of radio coverage WiFi connection can be used for networking, if the wireless router connected to a ADSL line or other access to the Internet, is also known as "hot spots."