Multiplexing

Multiplexing is a process of processing data in such a way as to have many channels or streams (of data) used for a single purpose (or a single stream of data is processed by multiple channels, so that the number of streams processed by a unit is very large). This can be done by using such hardware (interrupt multiplexers or discrete), or (more traditionally) by taking advantage of multiple links or channels within a given OS (for example by using a network card for remote access to a server).

 

History of Multiplexing

The notion of multiplexing has had a long, complex history. The concept was first described by B. F. von Laue (1935) in his monograph "The Dual System" but the term 'multiplex' is not mentioned until a few years later when von Laue and Christian Willkomm introduced it in their book "Phonons, Patterns and Systems" (1955). The English word 'multiplex' is a contraction of the phrase 'multiplexing and demultiplexing' and, while initially unknown in the international technical community, became widely used in later years. The suffix '-plex' originated in time-division multiplexing (TDM) or line rate multiplexing (LR/LRx). However, since the suffix is pluralized, it was originally used for multiplexing and demultiplexing which were grouped together in the classification given by Pohlmann et al.

 

Types of multiplexing

There are many types of multiplexing equipment in the market. TDM is one of the most popular technologies because it is easy to implement. It is possible to divide the total bandwidth into parts and split it up into smaller pieces. This way a user can get more data with a single connection. FDM multiplexing (also called FDD) is a digital signal processing technique that applies a technique that splits the Internet in multiple fiber-optic paths, sending each fiber to a separate customer. If two users each have a fiber connection in the same part of the network, this technique can be used to combine the connections into one, improving the network capacity. There are many disadvantages of TDM multiplexing. First of all, you have to buy a server (or multiple servers) to operate the network.

Some other types of multiplexing are Frequency domain multiplexing, DC-specific multiplexing, FPGA-based RF multiplexing. Using a mix of wireless channels Frequency-hopping spread spectrum and other techniques electromagnetic propagation on moving channels. Frequency-hopping spread spectrum, directional multiplexing SDMA, SDMA-based multiplexing (SPDMA), Diffusion-based multiplexing.


What is multiplexing used for?

Multi-threading. On a server or computer with only one processor, there is usually a limit to the number of threads that can run in parallel. As you add more cores, for example on a multi-processor system, the programs running on those cores can become rather “messy” and it can be difficult to tune the programs to run smoothly with the other programs. Multiplexing allows the processors to run different programs in parallel without going through the trouble of creating and maintaining, two or more programs. On a server or computer with only one processor, there is usually a limit to the number of threads that can run in parallel.

Multimedia 

Multimedia classification: this is probably the easiest, since what the camera can do is the basics, but is quite useful when you want to keep more of the video as an MP4. It is used for image zoom, 2-axis panoramic stitching, depth of field zoom (usually mono, but stereo if the camera is only able to record mono, like the all-directional modes), it is also used for zooming through an individual frame, and panning. 

Multi-channel 

Multichannel processing System for processing a stereo signal into monaural sound. The latter uses a codec to separate the audio channels (subtitles, captions, dialog, and music). Several codecs are provided by a hardware encoder, but since it is done at the input level, each codec generates a mono signal by itself, it is not a pure mixer.


Advantages of multiplexing     

Multiplexing is the key to streaming applications. Streaming applications are applications that require the client software to have many different "channels" (single packets) to the server. Streaming applications often also involve sophisticated channel management to keep multiple streams

Time division multiplexing with channel coding is required for conversion of digital signal to analog. TDM, the most widely used. Time-division multiplexing provides greater speed than discrete FDM multiplexing. Time division multiplexing is more resistant to jitter than FDM multiplexing. Time division multiplexing offers the smallest headroom (the range of the digital-to-analog converter) of the two techniques. Conversion from digital to analog can be done at extremely low signal levels.

FDM: What is FDM? FDM is also known as time-division duplexing (TDD). FDM uses a digital-to-analog converter called digital to analog converter (DAC), which is capable of decoding a digital signal into an analog signal.

There are four types of DACs – PLL DAC, FFT DAC, Full Duplexed DAC, and Phase-Locked Loop DAC.

 

Which is better TDM or FDM?

FDM and TDM (Tower to clouds) are all ways to distribute signals in a network. When both sides of a transmission share the same physical medium, TDM and FDM will result in line and/or plain noise. Differential interference in a TDM network has a particularly noisy result. FDM using optical fiber instead of copper has lower noise, but it also has a higher latency. Another common aspect of TDM and FDM is it uses physical distribution with a potential for high loss. TDM As you probably know, in a symmetric channel, the signal is just plain and simple. Either you send 1 bit or 0. In a two-channel or three-channel, we have the ability to stream both 1s and 0s at once.

 

What is the IEEE 802.11a standard for wireless LANs?

What is the WiMAX standard for wireless LANs? IEEE 802.11b and 802.11c - The IEEE 802.11b specification includes: 802.11b (Received Propagation Time) and 802.11b (Proximity) bands are 40MHz and 80MHz respectively 802.11b use a PCM system, a feature that allows for error correction for data packets 802.11b has a data rate of 1 Mbps and is capable of supporting 64 channels 802.11b is backward compatible with 802.11a 802.11b operates at the 2.4 GHz band and only supports 10MHz channels 802.11c (Current Standard) - 802.11c is an IEEE standard that supports backward compatibility with 802.11b (802.11a) It also allows for multiplexing at the same time over a much wider frequency.

Time domain multiplexing (TDM) is the technique of moving the electrical signal along a single path or channel. The common way to do this in optics is to distribute it into channels that are physically separate, so that only a channel is active at any given time. The relative delay of any two channels is less than or equal to the transition time of the signals from channel to channel, and the multiplexing process ensures that there is no signal loss between channels, while maintaining high-speed operation. 

The key aspect of TDM is that its operation is not limited to a single channel. If two signals are beamed at one medium, and at a sufficiently close distance, their interleave (duplicate) at some in the context of wireless LANs spectrum analysis and management RF multiplexing 


Conclusion

Multiplexing is one of the most versatile methods for synchronizing data and helping end-users perceive improved performance in digital networks. It reduces bottlenecks in the network, effectively gives end-users the freedom to use more of their devices. Depending on the type of multiplexing in use, TDM and FDM provide some complimentary benefits and downsides. In this article, we describe some of the different types of multiplexing and explain how they are used in modern, digital networks.