Tag Archives: frequency

Spread Spectrum Concept

Dsss – Direct sequence spread spectrum DSSS – Direct Sequence Spread Spectrum is a spread spectrum technology in which original data is expand using PN code randomly to reduce noise and this also provide high security to data as is…

Difference Between OFDM and FDM in LTE

FDM in LTE Conventional multi-carrier operation as it is used for FDM works simply by selecting a number of center frequencies – one for each carrier to be used. The center frequencies must be spaced. In fact there is a…

What is the difference between 4G and 4G LTE?

Many people use the terms 4g and 4g interchangeably, but they are not the same. Lets find out the difference…. Features of 4g 4G is the next step above and a 3g replacement, offering faster speeds for users who stream…

How Many Broadcast Channels & what’s it work in GSM ?

BCCH(Broadcast Control Channels) Downlink Only. Broadcast information of the serving cell (System Information). Transmitted on timeslot zero of BCCH carrier. Read only by idle mobile at least once every 30 secs. SCH (Synchronization Channels) Downlink Only Carries information for frame…

Main Characterictics of WCDMA

Support two basic modes: FDD and TDD modes High chip rate (3.84 Mcps) and data rates (up to 2 Mbps) Employs coherent detection on uplink and downlink based on the use of pilot symbols Inter-cell asynchronous operation Fast adaptive power…

WCDMA Radio Interface Channel Definition

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 = specification of the information global content providing the real transmission…

CDMA Channel Frequencies & Calculation

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       869-894MHz Used for the Forward link communication The CDMA band…

Which Bands Used in WCDMA ?

There are different band in different country but most of commonly used band we will discuss here. Main bands : means basic band when 3G commercial launch by Private or public sector. 1920 ~ 1980MHz / 2110 ~ 2170MHz Supplementary bands: different…

3G Spectrum Allocation

How 3G Spectrum Allocation? 3G Spectrum Allocation is different in different country but mainly its all having as per below figure. ITU has allocated 3G Spectrum Allocation 230 MHz frequency for the 3G mobile communication system IMT- 2000: 1885 ~…

OFDMA Transmitter in LTE

How OFDMA Transmitter in LTE ? In the downlink, OFDM is selected to efficiently meet E-UTRA performance requirements. With OFDM,  it is straightforward to exploit frequency selectivity of the multi-path channel with lowcomplexity receivers.  This allows frequency selective in addition…

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 shift registers and XOR gates .   Masking will cause…

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   (XOR)  0101   ——   0101 • Generation Sequence:…