CDMA

Get Here about CDMA technology and How CDMA Works, CDMA Solution and CDMA RF Optimization.


MOBILE TRANSITION INTO DIFFERENT STATES

  A mobile will in one of four states after it is powered on. Initialization State In the Initialization State, the mobile tunes to the first preferred RF frequency channel

Propagation Path

Radio wave can be propagated from the transmitting antenna to the receiving antenna in many ways: perpendicular incidence wave or ground refraction wave, diffraction wave, troposphere reflection wave, ionosphere reflection

Propagation of Electromagnetic Wave

When the radio wave propagates in the air, the electric field direction changes regularly. If the electric field direction of radio wave is vertical to the ground, the radio wave

Radio Wave Spectrum

The radio waves are distributed in 3Hz ~ 3000GHz. This spectrum is divided into 12 bands, as shown in the above table. The frequencies in each specific band present unique

PN Code Generation & Masking

  PN Code Generation PN Code Generation PN codes are generated from prime polynomials using modulo 2 arithmetic. The state machines generating these codes are very simple and consist of

How Walsh Code Generate in CDMA

• Definition: Orthogonal functions have zero correlation.  Two binary sequences are orthogonal if the process of “XORing” them results in an equal number of 1’s and 0’s. Example:   0000

Spread Spectrum Concept

CDMA IS A SCHEME IN WHICH MULTIPLE USERS ARE ASSIGNED RADIO RESOURCES USING THE DIRECT SEQUENCE – SPREAD SPECTRUM (DSSS) TECHNIQUES. ALTHOUGH ALL USERS ARE TRANSMITTING IN THE SAME RF

How Many CODES in CDMA?

There Are Three Codes in CDMA PN Long Code,PN Short Code & Walsh Code. PN Long Code The Long Code is a PN sequence that is 242 – 1 bits

Interference Margin for CDMA

In determining RF coverage in CDMA systems, the effect of interference generated from the serving cell as well as the neighboring cells must be considered, this is in contrast to