What is eb no in cdma

Ham Topics. Assorted Topics. Community Topics. Site Info. Read the article and associated links below to find out more about this important subject! Figure 1. His website is at www. It's a good paper, but I have a tiny little nit.

I see two problems with using receiver noise bandwidth in this equation. The other problem is that there's more than one definition of bandwidth. Noise bandwidth is just one of many. Then I turn off the signal source, turn on the noise generator, and measure the noise power on the analyzer with the resolution bandwidth set to the user data rate.

Naturally I have to ensure that both signal and noise swamp the analyzer's own noise. Setting the analyzer RBW to the user data rate simplifies the calculation by causing the data rate and noise bandwidth terms to cancel and fall out of the equation.

This fellow claims to have invented a family of "ultra narrow band" modulation methods that are in fact ultra wide band UWB plus a very strong carrier that wastes most of the signal power. Among many other mistakes, he has fallen into the trap of confusing noise bandwidth with other, more relevant definitions of bandwidth, and his receivers have filters with noise bandwidths that are much smaller than the Nyquist rate. This is how he has fooled himself into thinking that his signals are narrow band.

Anyway, thanks again for the article you published way back in Regards, Phil. From: Steve Liang, Wednesday, July 22, a. Jim and Phil- I wasn't thinking clearly this morning. Still like to have BER vs. I can't speak to our own decoders off the top of my head, but plots for the common FEC schemes are also in the textbooks, certainly for the common Viterbi decoded codes.

Note that "The Viterbi Algorithm" is an algorithm for decoding convolutional codes. There's no such thing as a "viterbi code. It is decoded by one of several methods, some including modified versions of the Viterbi algorithm that can produce "soft" decisions, i. This is important in decoding turbo codes since the process is iterative, feeding the results of one decoder into another until the data stops getting better.

Phil, Thank you for the fast response. SS Glossary. This is because the correct answer is … it depends! Although this ratio is of fundamental importance to any cellular system, is not well understood by many professionals.

On the opposite side, professionals with a good understanding of this ratio are able for example, to correctly assess the RF links, and also to perform more extensive optimizations, obtaining the best possible performance of the system. To begin, we define the basic concepts of Eb and No. They are basic for any digital communication system, and generally we talk about it when we deal with Bit Error Rate and also Modulation techniques.

Do not worry. Indeed, only with the theoretical definition is still very difficult to see how this ratio is used, or how it can be measured. These curves are used as follows: for a certain RF signal, which is the bit errors rate that I have? Is this bit error rate acceptable for my system? In other words, we can theoretically determine how the performance would be for the digital link.

Note: it is worth remembering here that this is a very complex subject. As always, we try to introduce to you the most simplified possible through the use of examples and simple concepts. For example, a concept that could be explored here - since we are talking about digital communication system - is the Noise Figure. But we do not want to repeat here all the theory explained in the University. Nor was it to have mentioned the noise figure here, but as we talked about it, just understand as a noise level that every receiver has, and that it is due to the process of amplification and processing of signal.

Concepts like this, and other even more complex, can be studied, if you wish. As we are speaking of codes, it becomes easier to understand the concepts by observing a simplified diagram of Spread Spectrum Modulation.

In red, in transmitter have a narrowband signal with data or voice modulated. This signal is spread and transmitted. And spreads through the middle air. In the receiver, the signal is despread - using the same sequence that was spread - and thus recovering the base narrowband signal.

To proceed, we must know some more definitions. Io : Interference is the Broadband; Interfering co-channel, including yourself setor. E : is the signal average energy - do not confuse it with the sinal average power. Note: With these concepts, several formulas can be derived with different numerators and denominators. Again, it is not our purpose here today. We only mention a few concepts, related.

Then come back to the practical level - noting that theoretical approaches can be done more easily later, after the basics are understood. It is primarily a parameter related to the manufacturer for different bearers based on the channel model. But it can also vary with the environment urban, rural, suburban , speed, diversity, use of power control, application type, etc…. Otherwise: for CDMA interference is like a noise, then both can be considered the same thing.