Data rate

8P8C connector .

Data transfer rate - the amount of data transmitted per unit of time ^[1] . The maximum data transfer rate without errors ( bandwidth ) together with the determine the performance of the system or communication line. The theoretical upper bound on the transmission rate is determined by the Shannon-Hartley theorem .

Shannon's theorem - Hartley

Considering all possible multi-level and multi-phase encoding methods, the Shannon-Hartley theorem claims that the capacity of the channel C , which means the theoretical upper limit of the information transfer rate, which can be transmitted with a given average signal power S through one analog communication channel, subjected to additive white Gaussian noise of power N is equal to:

$C=B\log _{2}\left(1+{\frac {S}{N}}\right)$ ${\ displaystyle C = B \ log _ {2} \ left (1 + {\ frac {S} {N}} \ right)}$

Where

C - channel capacity in bits per second;

B - channel bandwidth in hertz;

S is the total power of the signal over the passband measured in watts or volts squared;

N is the total noise power above the passband, measured in watts or volts squared;

S / N - signal to Gaussian noise ratio, expressed as power ratio.

Units

Bit per second

Bit per second ( bps ) is the basic unit of information transfer rate used at the physical layer of the OSI or TCP / IP network model.

At higher levels of network models, as a rule, a larger unit is used - bytes per second (B / c or Bps , from English b ytes p er s econd ) equal to 8 bits / s.

Unlike bauds ( baud ; in binary encoding, bauds also indicate the number of bits per second), bits per second measure the effective amount of information, excluding service bits (start / stop / parity) used in asynchronous transmission . In some cases (in synchronous binary transmission ), the baud rate may be equal to the bit rate per second.

Baud

Baud ( eng. Baud) in communications and electronics - a unit of measurement of symbolic speed , the number of changes in the information parameter of a carrier periodic signal per second . ^[2] Named after Emil Bodo , inventor of the Bodo code - character encoding for teletypes .

Often, mistakenly, it is believed that the baud is the number of bits transmitted per second. In reality, this is true only for binary coding, which is not always used. For example, modern modems use quadrature amplitude modulation (QAM - QAM), and with one change in the signal level several (up to 16) bits of information can be encoded. For example, at a symbol rate of 2400 baud, the transmission speed may be 9600 bps, due to the fact that 4 bits are transmitted in each time interval.

In addition, bauds express the full capacity of the channel, including service characters (bits), if any. The effective channel speed is expressed in other units, for example, bits per second (bits / s, bps).

Methods for increasing the speed of information transfer

One of the ways to increase the speed of information transfer is the use of digital antenna array technology and the implementation on its basis of adaptive antenna arrays with weakly correlated antenna elements ^[3] . Communication systems that use such antennas are called MIMO systems (Multiple Input Multiple Output). ^[4] ^[5] . The increase in their throughput is achieved by increasing the number of antenna elements based on Massive MIMO technology .

The transmission rate of useful (in human terms) data is always less than the transmission rate of information due to the presence in the network protocols, in addition to the protocol load, there are also service headers.

Notes

↑ ¹ ² How to calculate data transfer speed // wikiHow
↑ Olifer V.G., Olifer N.A. Computer networks. Principles, technologies, protocols. - St. Petersburg: Peter, 2001, 672 p.: Ill. ISBN 5-8046-0133-4
↑ Flaksman A. G. Adaptive spatial processing in multi-channel information systems / Flaksman A. G. // Dis. Dr. Phys.-Math. sciences. - M.: RSL 2005 (From the funds of the Russian State Library), p. 5
↑ Slyusar, Vadim MIMO Systems: principles of construction and signal processing. (unspecified) . Electronics: science, technology, business. - 2005. - No. 8. P. 52-58. (2005).
↑ Slyusar, V.I. Basic concepts of the theory and technology of antennas. Antenna systems of Euclidean geometry. Fractal antennas. SMART antennas. Digital antenna arrays (CARs). MIMO – systems based on the CARs. (unspecified) . Sections 9.3 - 9.8 in the book "Broadband Wireless Information Networks." / Vishnevsky V.M., Lyakhov A.I., Tailor S.L., Shakhnovich I.V. - M .: Technosphere. - 2005.P. 498 - 569 (2005).

Literature

Information transfer rate // In the book. Zyuko A. G. Immunity and efficiency of communication systems. M .: "Communication", 1972, 360p., Pp. 33-35

[wikihow-1] ¹ ² How to calculate data transfer speed // wikiHow

[2] Olifer V.G., Olifer N.A. Computer networks. Principles, technologies, protocols. - St. Petersburg: Peter, 2001, 672 p.: Ill. ISBN 5-8046-0133-4

[3] Flaksman A. G. Adaptive spatial processing in multi-channel information systems / Flaksman A. G. // Dis. Dr. Phys.-Math. sciences. - M.: RSL 2005 (From the funds of the Russian State Library), p. 5

[slyusarmimo1-4] Slyusar, Vadim MIMO Systems: principles of construction and signal processing. (unspecified) . Electronics: science, technology, business. - 2005. - No. 8. P. 52-58. (2005).

[slyusarsmartantenna1-5] Slyusar, V.I. Basic concepts of the theory and technology of antennas. Antenna systems of Euclidean geometry. Fractal antennas. SMART antennas. Digital antenna arrays (CARs). MIMO – systems based on the CARs. (unspecified) . Sections 9.3 - 9.8 in the book "Broadband Wireless Information Networks." / Vishnevsky V.M., Lyakhov A.I., Tailor S.L., Shakhnovich I.V. - M .: Technosphere. - 2005.P. 498 - 569 (2005).