Multiple Access Technologies

The end-to-end communication chain as defined in a mobile telecommunications network consists of a number of interleaved technologies responsible for the sampling, converting, encrypting, encoding, multiplexing, routing, etc. of the data flows in a way that voice calls and data sessions are established and maintained within quality levels acceptable to their users.

Multiple access technologies are widely deployed in modern wireless and wireline telecommunications networks. In fact their use is essential for resolving any communications system's dilemma - the accommodation of a large number of users within a transmission medium of limited availability and capacity. While adding more capacity in the case of wireline networks is done in a fairly comprehensive manner, the latter could pose important challenges in the wireless domain. In wireless networks users are given access to voice and data services via the so called AI (Air Interface) also known as the radio interface.

The AI is composed of modulated radio signals or carriers as part of the electromagnetic spectrum allocated to mobile network operators by government regulatory agencies. Due to its physical properties and service based allocation, the electromagnetic spectrum is a scarce resource subject to tight regulations and quite expesnive to acquire, often via public bidding. For that reason mobile network operators are left with a single option when it comes to handling large volume of information flows with reasonable congestion limits within the available electromagnetic spectrum - the deployment of AI specific multiple access technologies.

Multiple access technologies harness the power of dynamic resources allocation algorithms and exploit a major weakness in the audio-visual senses of humans - latency! As our ears and eyes are too slow to notice interruptions in the information streams above certain frequency of occurrence, information flows are digitized and structures in physical and logical frames. For voice the minimum frequency of occurrence is set to 125 microseconds or 8000 frames per second, while for motion pictures it's equal to 42 milliseconds of 24 frames per second. The huge gaps in time in-between can be used to combine other users' data streams into the same physical and logical transmission channels.

It is important to maintain a good level of knowledge and understanding in the AI specific multiple access technologies as they hold the key to a successful deployment and operation of any mobile telecommunications network.

In the related content you can find a list of the most commonly used multiple access technologies in wireless communications.

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