Search Engine www.edaboard.com

# Performance Qpsk

21 Threads found on edaboard.com: Performance Qpsk

## MMSE based Equalization in OFDM systems

Hi, What is the performance difference of MMSE equalizer and ZF equalizer in a OFDM system. I have simulation 3 tap Rayleigh channel for qpsk ODFM system and found out that both the equalizers give the same performance. But in Single carrier Frequency Domain Equalization, MMSE performs significantly better than ZF. I modeled (...)

## wat is O-QPSK modulation .

Let me clarify something. Tye adavtage of O-qpsk over standard qpsk is that the evelope of the band-limirted modulated signal has much less variations. This allows the use of nonlinear high power amplifiers in the transmitter without high spourious generation level. Theoretical performance (BER vs. Eb/No) is the same. Regards Z

Help me, please...... I tried to make a simulation how a system with no diversity goes trough Rayleigh channel. I used qpsk modulation. But the performance graphic looked so bad (I mean, it was not like a "waterfall". It had no pattern at all). The fading model ran well on system with MRC. But not with single input single output. Does anyone know

## DVB-S2 LDPC Performance

Hi! I need to simulate with Matlab a qpsk and 8PSK modulations using LDPC Coding. I need to obtain the theoricals graphs of the Eb/No and BER relationship for differents code rates and modulations (in fact, I need to obtain the graphs for Eb/No and BER relationship for a DVB-S2 system), but I can't find a BER formula for LDPC codes. Thanks!

## rayleighchan and AWGN functions

hi all i am trying to simulate qpsk in flat fading channel , i do it by a classical way but when i use raylieighchan and awgn i got non proper performance %code h=raylieghchan; x=filter(h,data); Rx=awgn(x,snr,'measure'); do any1 know why??

## plz give me matlab code for Bit error versus SNR .

i have a term paper on performance analysis of bit error rate and snr for bpsk and qpsk.....plz provide me the code.... i m ne in matlab and digital communication.... thanks

## Regarding cdma.......

I Need MATLAB code for performance analysis of Multi- tone CDMA using OFDM-qpsk......plz anyone help for me..................

## Help me implement channel equalization in Matlab

I need to implement the following: 1. BPSK modulator + Racian Fading Channel + AWGN +MMSE Equaliser + BPSK Demodulator 2. qpsk modulator + Raleigh Fading Channel + AWGN +Zero Forcing Equaliser + qpsk Demodulator I need to implement in MATLAB to study their performance. I would appriciate if someone halp me to start and tell me (...)

## Why is OFDMA still used despite SC-FDMA better performance?

I know there are so much debates on these two techniques. I am just curious why they are still using OFDMA despite the fact that SC-FDMA has a better PAPR performance. Any supporting papers or documents?

## BER for OFDM using QPSK & Convolutional Encoding

Hello, I have tried to simulate the performance of an OFDM system using qpsk a rate 1/2 convolutional code and a Viterbi decoder at the receiver. The problem I face now is after plotting the results, I come up with a funny graph that doesn't look anything like the theoretical result. Here's an attachment of the MATLAB image i obtained. Can an

## Matlab QPSK... have you observed this?

How pskmod.m works? I mean qpsk is supposed to make two bits as input and output one symbol. But when I use pskmod(,4), the length of the answer remains same i.e. 8 and not 4 I wonder if this is going to affect the BER performance of qpsk in Matlab I know the solution too that I can use reshape and blah blah blah, but I wa

## Performance of BPSK vs QPSK

I understand that the bit error performance of BPSK and qpsk are the same. Does this mean that if I fix the transmitter power (eg. 1W), at the receiver I would be able to have the same performance, no matter whether I am using BPSK or qpsk. Also the Es/No for qpsk is 3dB worse than BPSK. However, since (...)

## ISSUE FOR BER in MATLAB

HI Dear : Have u any idea about BER performance of qpsk in AWGN for matlab Regards mak

## Which one is better QAM or QPSK?

These will be identical performance at identical power levels. Your main problem will be in reducing the "implementation loss" of the real decoding hardware.

## Two questions on two mixers input

1) when lna single output,one of double balanced mixer input is grounded and the other with signal , will it deteriorate the system performace ? ( qpsk signal) 2) two mixer input with different amplitude (1dB or so) or phase not exactly 180. it will apparently degrade the performance. I think it can be fixed in digital algorithm .right?

## help on concatenated Reed-solomon and convolutional QPSK

I am doing a matlab simulation on qpsk mod and demod passing thru AWGN channel. I am double encoding my signals to get better performance. The coding is RS(31,27) act as outer coding and rate 1/2 constrain length 7 polynomial (171,133) convolutional code act as inner coding. After doing all these with qpsk demod, I could not get the expected (...)

## BER/SER and SNR in STBC and Alamouti scheme

hi, I am trying to understand STBC and Alamouti scheme. However, i am very confused about the BER of such systems. Referring to the performance results in Alamouti and Tarokh's papers, for qpsk (for example), the BER/SER shown is against SNR for 2 bit/sec/hz. 1- what does the "per hz" mean here? 2- why do we use SNR here instead of Eb/No

## HELP:Limitation on QAM-on Pilot subcarrier in OFDM ?

For qpsk constellation, decision boundary is +-45 degree, which is different from the phase error. For analysis of phase error on the performance of QAM, the phase noise could be modeled as Gaussian noise. Then you need evaluate the conditional error probablity due to the phase noise. It is more compilcated if the magnitude imbalance is also consid

## 3G circuits that employ QPSK modulation scheme

hi. thanks for your reply. i think 3G can work in qpsk modulation scheme. this is actually a project given where students need to model and assess the performance of qpsk modulation scheme with respect to the requirements for 3G services using ADS tools. is there any circuits?. pls help

## How to assess QPSK modulation scheme for 3G services?

UMTS is a 3rd Generation Mobile (3G) system that employs the qpsk modulation scheme for digital transmission, how to model and assess the performance of qpsk modulation scheme with respect to the requirements for 3G services using ADS tools?