In Mobile Communication, FDMA stands for Frequency Division Multiple Access. It is a channel access technique used in mobile communication systems to allow numerous users to share the available frequency spectrum. In first-generation (1G) analogy cellular systems and some early digital systems, FDMA is one of the multiple access mechanisms. Even though it is not frequently utilized in contemporary cellular networks, it is applied to some niche applications.

A thorough explanation of FDMA in mobile communication is provided below:

Principle of FDMA

The foundation of FDMA is the division of the available frequency spectrum into numerous non-overlapping frequency bands, commonly referred to as channels. A particular user is assigned a channel for the duration of their communication session. Because they are using different portions of the frequency spectrum, several users can communicate with one another simultaneously by assigning them separate frequency bands.

Channel Allocation

In FDMA, a single communication channel is assigned to each of the smaller sub-bands that make up the frequency spectrum. One user at a time may utilize each channel. In an FDMA system, the total number of concurrent users is thus constrained by the number of accessible channels.

Signal Composition

The mobile device transmits and receives signals inside a particular allotted frequency channel whenever a user wishes to start a conversation. The user's voice or data is modulated onto the designated frequency carrier and sent to the base station through airwaves. Before sending the information to the core network, the base station receives signals from various users and divides them according to their allotted frequencies.

Early mobile communication systems mainly developed using frequency division multiple access (FDMA). It was widely employed in the first-generation (1G) analog cellular networks that were predominantly voice-based. When mobile devices and base stations' processing power and capabilities were constrained, FDMA's simplicity made it an appealing option.

In FDMA, the frequency spectrum was split into discrete bands or channels, each typically covering a small number of kilohertz. Mobile service providers assign particular channels to certain users or calls. The system allocated a free frequency channel for the length of each call made by a user.

More recent mobile communication generations, such as 3G, 4G, and 5G, switched to more sophisticated multiple access strategies to overcome these drawbacks. Orthogonal Frequency Division Multiple Access (OFDMA) and Code Division Multiple Access (CDMA) allowed more flexible data rate allocations, increased capacity, and improved spectral efficiency. These methods improved spectrum use and allowed several users to share the same frequency band simultaneously while reducing interference.

FDMA still finds niche applications in a few specialized communication systems, such as satellite-based networks or specific industrial wireless solutions, despite it no longer being employed in mainstream cellular networks. However, FDMA's legacy is still important since it cleared the path for creating more advanced and effective multiple access techniques that underpin the modern mobile communication landscape.

Advantages of FDMA in Mobile Communication

Simplicity: FDMA is easier to install and comprehend than more sophisticated multiple-access approaches. Its simplicity made it an appealing option for early mobile communication systems with limited computational power and technological skills.
No Synchronization Requirement: Since, each user runs in a different frequency band, FDMA does not require strict synchronization between users. This lessens the complexity of the entire system by streamlining the design and execution of mobile devices and base stations.
Low Complexity Handoffs: In FDMA, handoffs is the process of moving a call that is already in progress from one cell to another as the user moves are relatively straightforward. The handoff method requires switching the communication from one base station to another without changing the frequency channels since each user keeps the same frequency allotment within a cell.

Limitations of FDMA in Mobile Communication

Spectrum inefficiency: FDMA encounters issues with spectrum inefficiency, particularly when users need to utilize all of the assigned frequency channels. This may lead to wasted bandwidth, lowering the system's total capacity.
Fixed Data Rate: In FDMA, the bandwidth of the allotted channel determines the data rate for each user. Modern communication systems, where data rate needs differ dramatically between users and applications, may need more flexibility.
Limited Capacity: The quantity of available frequency channels limits the overall capacity of an FDMA-based system. As the user base grows, the system may get congested during periods of high demand.

Conclusion

In conclusion, Frequency Division Multiple Access (FDMA) was a crucial technology in the development of mobile communication. Simultaneous communication was possible without interference thanks to its ease of use and capacity to assign different frequency channels to users. However, FDMA's restrictions on data speeds, flexibility, and spectrum efficiency led to the creation of more sophisticated multiple access techniques in later mobile generations. While CDMA and OFDMA are superior technologies, modern cellular networks have adopted FDMA despite its historical relevance to meet the ever-increasing mobile communication demands.

← Prev Next →

Miscellaneous