What are channelisation codes used for?

The channelization codes are Orthogonal Variable Spreading Factor (OVSF) codes. They are used to preserve orthogonality between different physical channels. They also increase the clock rate to 3.84 Mcps. The OVSF codes are defined using a code tree.

How many scrambling codes are there in UMTS?

15.6 Spreading and Scrambling in UMTS

	Synchronization codes	Scrambling codes, downlink
Length	256 chips	38,400 chips
Duration	66.67 μs	10 ms
Number of codes	1 primary code/16 secondary codes	512 primary/15 secondary for each primary code
Spreading	No, does not change bandwidth	No, does not change bandwidth

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 code in telecom?

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.

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 difference between spreading and scrambling?

Channelization codes are generated recursively to form a binary tree structure (see Figure 15.20). Spreading is used in combination with scrambling. Scrambling is used on top of spreading to separate mobile terminals or cells from each other. Scrambling does not change the chip rate nor the bandwidth.

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?

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 scrambling in LTE?

In telecommunications and recording, a scrambler (also referred to as a randomizer) is a device that manipulates a data stream before transmitting. The manipulations are reversed by a descrambler at the receiving side. Scrambling is widely used in satellite, radio relay communications and PSTN modems.

Which codes are used as channelization codes to separate physical channels of a UE?

Purpose of WCDMA Channelization Code

• Channelization code is used to distinguish different physical channels of one transmitter.
• For downlink, channelization code ( OVSF code ) is used to separate different physical channels of one cell.

What is scrambler and descrambler?

What is the scrambling code in LTE?

It is “Scrambling Code”. By using the scrambling code, NodeB can separate signals coming simultaneously from many different UEs and UE can separate signals coming simultaneously from many different NodeB.

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?

The spreading factor defines the relation between symbol rate and chip rate. A higher spreading factor increases sensitivity and range, but also prolongs the airtime of a packet and will likely raise the risk of a collision. LoRaWAN uses six different orthogonal spreading factors numbered 7–12.

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.

What is Cpich 3G?

CPICH stands for Common Pilot Channel in UMTS and some other CDMA communications systems. In WCDMA FDD cellular systems, CPICH is a downlink channel broadcast by Node Bs with constant power and of a known bit sequence. Its power is usually between 5% and 15% of the total Node B transmit power.

What is Telecom pilot channel?

Pilot Channel − Pilot channel is a reference channel. It uses the mobile station to acquire the time and as a phase reference for coherent demodulation. It is continuously transmitted by each base station on each active CDMA frequency. And, each mobile station tracks this signal continuously.

What is scrambling code in LTE?

What is spreading factor in 3G?

3G RX noise figure. The spreading factor (SF) is the ratio of the chip rate, 3.84 MHz, to the actual data rate, which is 30 kbps in this measurement.

What is a UMTS code?

UMTS codes explained. The UMTS World is an 3G mobile system news and information provider. Comprehensive coverage of UMTS / 3G news, licensing, business developments, 3G WCDMA telecommunication technology, multi media mobile phones and future communications.

How are channelization codes defined in the code tree?

Each level in the code tree defines channelization codes of length Spreading Factor (SF), corresponding to a spreading factor of SF. All codes within the code tree cannot be used simultaneously within one cell.

How many bits are there in the channelization code set?

and the channelization code set consists of seven bits xccs,1, xccs,2, …, xccs,7. The first three bits ( code group indicator) are determined as the unsigned binary representation of the following expression

What is the UMTS World?

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