To perform the transmission

To avoid that the signals of the different communicators without mobile recharge api distinction, each of them is assigned a unique code. Each code identifies a specific pseudo-random sequence to rate much higher than the transmission signal, said chip-rate. Multiplying the signal sequence is obtained for of the signal in frequency, that is, a widening of the band of the signal to a higher value, in practice the value of the bandwidth of the entire system.

The sequences being chosen to be orthogonal to each other (cross-correlation zero), the receiving and sufficient to correlate the received recharge integration signal with the same sequence; if the codes are actually orthogonal all contributions due to interfering sequences (no interest) will be null. This operation is called the spreading. The first advantage of the technique is in CDMA can reuse the entire frequency spectrum in adjacent cells without risk of interference; what is guaranteed by mobile recharge api the use of different spreading codes.

This is not the case in the accesses to the division of time and frequency (FDMA and TDMA), where of carrier frequencies occurs in cells spaced. The second advantage of CDMA is that there is a maximum threshold of users beyond which it is not possible to go, but as the number of users to be served gradually decreases the quality of service, it raises the value of the BER (bit Error Rate). This degradation soft service called soft blocking.

The effect of a spreading

The third and final advantage of CDMA is the protection of the multi party. Indeed, the receiver may reach different reflections of the same signal which in general have different amplitude and phase. Generally their sum produces a distortion of the original signal, as recharge integration is to some mobile recharge api constructive and destructive to other frequencies.

In CDMA the protection by this phenomenon is inherent in the use of codes, in fact, each code mobile recharge api is selected to have a low auto correlation; this means that the receiver is the replicas of the signal with a delay greater than a certain recharge integration threshold as the other interfering signals.

Services on mobile recharge api

The system supports UMTS services typical of the systems mobile recharge api currently popular with important news. Typical services are: business information, or anything related to the mobile office or, plus the ability to create virtual teams; Services economic/ financial, and everything that is related to virtual banking, to on-line billing, and financial transactions to be carried out with the new universal Sim-Card that will become real virtual credit cards.

Security Services and/ or social, possibility of fast connection to the emergency services; Communication services, such as video telephony and video conferencing, but also the use of transponders and automated speech recognition, in addition to location services instantaneous; Aid to transport, with prepaid tolls mobile recharge api or fleet management, as well as excellent ability to theft.

Use of the Internet, or browsing the WWW with portable terminals fully automated e-commerce instant, publishing on-line and translations on-line, as well as various broadcast a local basis; Teaching tools such as virtual school science labs or on-line, on-line libraries, language laboratories on-line; Entertainment, or functions of audio on demand or on-demand games, watching video clips, or itineraries of every part of the world.