1 What are the main reasons why CDMALTE and GSMLTE are curre

1. What are the main reasons why CDMA/LTE and GSM/LTE are currently NOT compatible?

2. What are the codes used in CDMA systems?

3. Assuming 1.288Mchip per second and a shift register of 42,how long will it take to transmit a long code (from the beginning of spreading time until the end of the sequence)?

Solution

1) Phone runs on the 2G and 3G spectrum. CDMA and GSM run on dissimilar 2G or 3G frequencies, therefore voice is not compatible between the two.

2) LTE the ordinary denominator runs on the 4G spectrum. CDMA now runs on Class 13 and GSM Class 17 LTE, therefore data is not compatible between the two.

PN codes:   Pseudo-random number is able to be generated very simply. These codes will sum to zero over an era of time. Though the sequence is deterministic as of the limited length of the linear shift register utilized to generate the sequence, they give a PN code that can be used within a CDMA system to give the spreading code required. They are utilized within many systems as there is an extremely large number that can be utilized.

A feature of PN codes is that if the similar versions of the PN code are time shifted, next they become approximately orthogonal, and can be utilized as virtually orthogonal codes within a CDMA system.

Truly orthogonal codes:   Two codes are supposed to be orthogonal if while they are multiplied together the result is added over an era of time they sum to zero. For instance a codes 1 -1 -1 1 and 1 -1 1 -1 when multiplied together provide 1 1 -1 -1 which provides the sum zero. An instance of an orthogonal code set is the Walsh codes utilized within the IS95 / CDMA2000 system.