The difference between Snr Ber Eb/n0 and its connection

   The signal -to-noise ratio (S/n) is the ratio of the average power of the transmitted signal to the average power of the additive noise, the ratio of the load to Noise (c/n) to the average power of the modulated signal and the average power of the additive noise, which are computed in the form of a logarithmic unit in DB.

For the same transmission system, the load-to-noise ratio is larger than the signal-to-noise ratio, and the difference between the two is a carrier power. Of course, the carrier power is usually very small compared with the transmission signal power, so the ratio of the load to noise is very close to the SNR.
In the modulation transmission system, the signal-to- noise ratio is generally used, and the signal-to- noise ratio is generally used in the baseband transmission system .

In the digital communication system, we often encounter the parameter that expresses the strong and weak relation between the signal and the noise---eb/n0, because different modulation techniques will be used in the system transmission, so the spectrum efficiency will be different under different modulation technology, and the spectral efficiency of a modulation symbol generated by K-bit mapping is kbit /s/hz, in this case, in the calculation of BER when considering the overall performance, if the performance of the horizontal comparison system, it is necessary to exclude the role of system efficiency, at this point can be started from a single bit to compare, eb/n0 can eliminate the problem caused by spectral efficiency.

The communication system with high spectral efficiency transmits more information, but the transmission reliability is poor; the communication system with low spectral efficiency is weak in transmitting information, but the transmission reliability is higher. Therefore, in order to determine the merits and demerits of a communication system, we must comprehensively compare the efficiency and reliability of the spectrum, and synthesize the validity and reliability in two aspects.

Eb/n0---ber relation curve can compare the system validity and the reliability of the system. The meaning of Eb/n0 is this: The EB represents the average signal energy on each bit, and the N0 represents the power spectral density of the noise. We know that different digital modulation techniques have different spectral efficiencies because their modulation symbols have different number of bits mapped, such as the ideal low-pass signal waveform calculation, a modulation symbol generated by the K-bit mapping is kbit/s/hz to achieve the spectral efficiency. Therefore, if the relationship between signal and noise is calculated in bits, the effect of spectral efficiency can be eliminated, which is to compare the reliability of various modulation technologies on the same spectrum efficiency. Below we quantitatively explain the relationship between Eb/n0 and c/n. Digital signals are composed of symbols, so the average power of the signal (C) is the average power of the symbol. The period of the modulation symbol is T, in order to simplify the problem, we temporarily cast off the effect of roll down coefficient, according to the ideal low-pass signal waveform calculation, the modulation symbol bandwidth of 1/t (low-pass bandwidth of 1/(2T)). Suppose a modulation symbol is generated by a K-bit map:

Average energy of a modulated symbol = symbol average power x symbol period =CXT

Average energy of a bit EB = modulation symbol average energy/symbol contains the number of bits =cxt/k
Power spectral density of a noise = average power of noise/symbol bandwidth =n/(1/t)

Thus, the visible eb/n0 is equal to c/n divided by K, which removes the influence of factor K related to spectral efficiency. Eb/n0 and c/n are often used in practical applications. Eb/n0 can comprehensively reflect the performance of the system, but not intuitive, because EB and N0 is not a system can be directly measured parameters, must be calculated, and c/n can be measured directly, but more one-sided. Therefore, when it is necessary to understand the reliability of the system directly, c/n is generally used, and eb/n0 is generally used when the performance of different systems needs to be compared horizontally.

SNR signal-to-noise ratio is a relatively fuzzy concept, in the analog communication system, the concept of signal-to-noise ratio is more appropriate, but in the digital communication system, the concept of using eb/n0d will be more appropriate. snr=s/n= (EB*RB)/(NO*W) = (eb/no) * (rb/w).

The formula for calculating the signal-to-noise ratio is snr=10*log10 (eb./no)

To sum up, the SNR and eb/n0 are used to denote the ratio of useful and interfering signals to measure the validity of the new number; BER is a BER curve, which is calculated from the specific signal-to-noise ratio and modulation curve. The error rate is related to the modulation mode and the signal to noise ratio as well as the eb/n0 curve.

The processing gain is originally the spread spectrum code rate/information bit rate, spread spectrum gain = Spread spectrum code rate/symbol rate. In a CDMA system, the eb/no = SNR X w/r is used when calculating the eb/no, and w/r is called the processing gain, in which case the Eb_n0=snr (in db) +10log10 (Processing_gain) of the DB unit.

The difference between Snr Ber Eb/n0 and its connection