Cdma, short for code division multiple access, is inherently associated with spread spectrum communication techniques. In a sho all the participating base stations use the same frequency, and the result is a macro diversity situation. Four different air interface signals are considered. In a cdma system the same signal can be transmitted over the air interface, on the same frequency, from several base stations separated by considerable distances. Cdma network interfaces um interface air interface. A cdma system is based around direct sequence spread spectrum techniques. Is95 air interface reverse and forward links is95 cdma and spreading codes. Air interface identification for software radio systems. The umts physical layer utilises direct sequence spread spectrum format to enable a multiple access scheme called code division multiple access, cdma to be used. Andreas willig communication networks group hassoplattnerinstitute university of potsdam. Difference between lte and cdma difference between. The lte system can be seen as an expansion of service beyond voice calls towards a multiservice air interface. The air interface is the wireless counterpart of the physical layer 1 in the osi model see osi model.
A1 interface carries call control signaling between msc and bsc. Gsm and dect signals, both of which use gmsk modulation and a tdma scheme. Florida institute for cybersecurity fics research cis 6930 cellular and mobile network security. Also called a radio interface, the air interface defines the frequency, channel bandwidth. One of the chief elements of the umts physical layer or radio interface is the signal format that has been adopted.