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What are the drawbacks of Walsh codes?
Question: What are the drawbacks of walsh codes?…Walsh codes have the following drawbacks :
- The codes do not have a single, narrow autocorrelation peak.
- The spreading is not over the whole bandwidth; instead the energy is spread over a number of discrete frequency components.
What is the use of PN sequence in CDMA?
PN Sequence It is simply a binary linear feedback shift register, consisting of XOR gates and a shift register. This PN generator has the ability to create a sequence identical for both the transmitter and the receiver, and retaining the desirable properties of the noise randomness bit sequence.
What is the use of PN sequence?
Pseudorandom noise (PN) sequences are used to spread and recover data in direct-sequence spread spectrum (DSSS) transceivers. We consider the problem of designing multiple PN sequences that are to be used as pilot signals and spreading sequences for transceivers whose clocks are not synchronized.
How do you create a PN sequence?
A PN data sequence is an M-sequence that is generated using a linear feedback shift-register circuit, as illustrated below. M is the number of shift registers. D(M) is the mth shift register, and {c1,c2,…,cM} are the coefficients of them.
What is meant by PN sequence?
Theory: Pseudo-Noise (PN) sequences are commonly used to generate noise that is approximately “white”. It has applications in scrambling, cryptography, and spread-spectrum communications. It is also commonly. referred to as the Pseudo-Random Binary Sequence (PRBS).
What is meant by PN sequence and give its properties?
Definition 1: A PN sequence is a (2n −1) length sequence that satisfies a linear recurrence, defined over GF(2), given by any corresponding primitive polynomial p(x) of degree n. Below, we provide all the properties of (2n − 1) length PN sequences along with a proof of each of them.
Which is an example of a PN sequence?
• Properties of PN sequence. • Data detection by correlation with PN code. • Application of PN sequence. • MAT-Lab Simulation for PN sequence generation. • Example of PN sequence 3. What is PN code? 1. A bit sequence that is random within the sequence length but repeats indefinitely 2.
Which is the channel number in the 64 Walsh matrix?
Each line of the 64 Walsh matrix 64 corresponds to a channel number. The channel number 0 is mapped to the first row of the Walsh matrix, which is the code of all zeros. This channel is also known as the pilot channel and is used to form and to estimate the impulse response of a mobile radio channel.
Which is an example of a PN code?
• Example of PN sequence 3. What is PN code? 1. A bit sequence that is random within the sequence length but repeats indefinitely 2. All its properties are predictable, if we know how it is generated 3. Easy to generate and synchronize 4. Other names: • Pseudo random bit sequences (PRBS) • m-sequences • Maximal length sequences 4.
What are the properties of a PN sequence generator?
4. A 15-stage PN generator using shift register 5. Properties of PN sequence • 1’s and 0’s occur with equal probability • Adding a shifted version to a PN sequence gives same PN sequence (in different phase) • High auto-correlation, low cross-correlation • Power spectrum contains all frequencies with sin2x/x2 envelop 6.