# What is the purpose of a scrambling code in UMTS?

## What is the purpose of a scrambling code in UMTS?

Table of Contents

Each base station in the UMTS mobile communication systems has a unique scrambling code called “primary scrambling code” that is used to allow terminals to differentiate each base station from other base stations in the system.

What is scrambled code?

Scrambling Codes are used to identify and distinguish cells from one another in WCDMA networks. These SCs are reported by the mobile users to the network to declare which cells they are able to connect to.

How many scrambling Codes are there in 3g?

There are two types of scrambling codes : long scrambling code and short scrambling code.

### How many scrambling Codes are there in the uplink?

15.6 Spreading and Scrambling in UMTS

Synchronization codes Scrambling codes, uplink
Number of codes 1 primary code/16 secondary codes 16,777,216
Spreading No, does not change bandwidth No, does not change bandwidth
Usage To enable terminal to locate and synchronize to the cells’ main control channels Separation of terminals

Does the scrambling code spread the signal further?

Because scrambling is used on top of spreading as shown Figure 1, it does not change the bandwidth of the signal, but only makes the signals from different users separable from each other [3].

How many PSC are in UMTS?

They are divided into 512 aggregations，each aggregation has 1 primary scrambling code (PSC) and 15 secondary scrambling codes (SSC).

#### What is primary scrambling code in 3g?

What is a channelization code?

The channelization codes are Orthogonal Variable Spreading Factor codes that preserves the orthogonality between a user’s different physical channels. The OVSF codes can be defined using a code tree.

What is scrambling in CDMA?

Long Code Scrambling The decimation is accomplished by essentially using every sixty-fourth bit out of the long code data stream. A sixty four times decimation reduces the data rate of the long code from 1.2288 Mbps to 19.2 kbps.

## How do you change the code on scrambled?

To change the scrambling code while on a connection, you must perform a Physical Channel Reconfiguration. After completion of the Physical Channel Reconfiguration procedure, successful or not, the Scrambling Code setting is overwritten with the value of PCR Target Cell Scrambling Code.

What is PSC in 3G?

In UMTS, the PSC is a kind of local cell identifier. It is “locally” unique in that all neighboring cell, as well as all neighbors of these cells, are guaranteed to have a different PSC than the current cell. It also means that you will not ever encounter two neighboring cells with the same PSC.

What is the function of Ovsf codes in the system?

OVSF codes are primarily used to preserve orthogonality between different channels in a communication system. Note that CN is only defined for N a power of 2. It follows by induction that the rows of CN are orthogonal. The OVSF codes can also be defined recursively by a tree structure, as shown in the following figure.

### What is spreading factor in WCDMA?

WCDMA uses Direct Sequence spreading, where spreading process is done by directly combining the baseband information to high chip rate binary code. The Spreading Factor is the ratio of the chips (UMTS = 3.84Mchips/s) to baseband information rate. Spreading factors vary from 4 to 512 in FDD UMTS.

What is Ovsf code in UMTS?

• OVSF stands for Orthogonal Variable Spreading Factor. They are also referred as channelization codes. They are used to separate data and control channels from same UE. • It preserves orthogonality between these control and data channels.

What is the chipping rate of UMTS?

The chip rate for Cdma2000 and GSM are 1.2288 Mcps and 27.0833 Ksps respectively.

#### What is chip rate in UMTS?

WCDMA specifications summary

WCDMA Summary
Parameter Details
Transmitted symbol rate 3.84 Msps
Signal bandwidth 3.84 MHz

Why scrambling is required?

The function of the scrambling is to remove long string of ones (1s) and zeros (0s) from the digital binary data. Scrambler is used in physical layer transmitter where as descrambler is used at receiver. The scrambling does not increase or decrease the bit rate i.e. the input and output bits are same in size.

What is scrambling of data?

Data scrambling is the process to obfuscate or remove sensitive data. This process is irreversible so that the original data cannot be derived from the scrambled data. Data scrambling can be utilized only during the cloning process.