Tag: cdma

Different modulation methods corresponding to different transmitting abilities in air interface. R99/R4: QPSK HSDPA: QPSK or 16QAM The UTRAN air interface uses QPSK modulation in the downlink, although HSDPA may…

Logical Channel = information container  Defined by is transferred. Transport Channel = characteristics of transmission Described by and with data is transmitted over the radio interface . Physical Channel =…

How Process Gain works in 3G? Process Gain = 10 Log (Chip rate/Bit Rate) Process gain differs for each service. If the service bit rate is greater, the process gain…

How Orthogonal Code works in WCDMA? 1.Coding By spreading, each symbol is multiplied with all the chips in the orthogonal sequence assigned to the user. The resulting sequence is processed…

The 850MHz CDMA band is most popularly used all over the world.This band as mentioned in the previous slide works between       824-849MHz Used for the Reverse link communication      …

AMR (Adaptive Multi-Rate) Speech A integrated speech codec with 8 source rates The AMR bit rates can be controlled by the RAN depending on the system load and quality of…

Block coding is used to detect if there are any uncorrected errors left after error correction. The cyclic redundancy check (CRC) is a common method of block coding. Adding the…

Rake Receiver Instead of trying to overpower or correct multipath problems, CDMA takes advantage of the multipath to improve reception quality in fading conditions. CDMA does this by using multiple…

EPC ( Evolved Universal Terrestrial Radio Access Network) Functionally the EPC is equivalent to the packet switched domain of the existing 3GPP networks. EPC consist of:–MME (Mobility Management Entity)–SAE GW…

Second-generation broadband wireless systems were able to overcome the LOS issue and to provide more capacity. This was done through the use of a cellular architecture and  implementation of advanced-signal…