Category: 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…

     In an actual application, the system implements the modulation in this way:  as shown above, I and Q channel sequences in the figure represent two channels of cyclic PN…

The original release of the EIA/TIA-95-B standard defined the protocol messages and formats to be used in the CDMA system. This release is know as Revision 0 of the IS-95…

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…

Here I write about EVDO (HSD) reverse channel in short or summarize defination. The EVDO channels for the reverse connection have a similar structure as for CDMA2000. The reverse link…

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…

For both mobiles and base station in direct sequence CDMA must be synchronized. In the IS-95A system, synchronization is based on the Global Positioning Satellite system time. The CDMA system…

The Base Station transmitter signal is, however, the composite of many channels (with a minimum of four). The Pilot channel is unmodulated (Walsh code 0); it consists of only the…

The CDMA reverse link uses a different coding scheme to transmit data. Unlike the forward link, the reverse link cannot support a pilot channel for synchronous demodulation (since each mobile…

Forward Traffic Channel is used to Transmit Data and Signaling Information. Symbol repetition makes symbol streams at different rates adapted to those at the rate of 19.2k. The original symbol…