Frequency Division Multiplexing (FDM) Technology: Applications of Frequency Division Multiplexing in Wireless Communication

# 1. Introduction

## 1.1 Background and Development of Wireless Communication

With the continuous advancement of technology and the increasing demand for information transmission, wireless communication has gradually become the mainstream method of communication. Wireless communication technology has attracted widespread attention and application for its flexibility, efficiency, and convenience. It plays a significant role in areas such as mobile phones, broadcast television, and wireless local area networks.

As mobile phones become more widespread, so does the demand for communication quality and network capacity. Traditional analog communication methods can no longer meet current demands, and digital communication technology has gradually become the norm. Frequency Division Multiplexing (FDM) plays a key role in digital communication systems.

## 1.2 Importance of FDM Technology and Introduction to Application Areas

Frequency Division Multiplexing technology is a technique that assigns different signals to different frequency bands for transmission. It enables multiple signals to be transmitted simultaneously in the same communication medium by dividing different signal spectrums.

FDM technology has a wide range of applications in the field of wireless communication. In mobile communication systems, FDM is used to allocate different users' communication signals, enabling simultaneous communication among multiple users. In the broadcasting domain, FDM combines different frequency broadcast signals, allowing multiple radio stations to transmit programs simultaneously on the same frequency band. Additionally, in data communication networks, FDM is widely used for multi-channel transmission, enhancing network data transmission speed and capacity.

In summary, FDM technology plays a crucial role in wireless communication, providing efficient and reliable signal transmission solutions for various application areas.

# 2. Basics of Frequency Division Multiplexing

Frequency Division Multiplexing (FDM) is a form of multiplexing technology that divides the available spectrum into multiple non-overlapping sub-channels and assigns each sub-channel to different users or applications, allowing multiple communication signals to be transmitted simultaneously on the same frequency band. FDM technology is widely used in wireless communication, broadcasting, and data communication networks.

### 2.1 Definition and Principles of FDM

FDM is a technology that divides multiple communication signals in the frequency domain and multiplexes them. Its principle is based on two assumptions: first, different communication signals do not overlap in the frequency domain; second, each communication signal exists only within its assigned frequency band.

The main steps of FDM are to divide the available spectrum into several sub-channels, with each sub-channel's bandwidth limited to the bandwidth required for each communication signal. Then, each sub-channel is assigned to the corresponding communication signal to ensure that different signals do not interfere with each other.

One of the advantages of FDM is that it can achieve the parallel transmission of multiple signals, improving spectral efficiency. Additionally, different signals are independent of each other, so even if one signal fails, it will not affect the transmission of other signals.

### 2.2 Frequency Division and Channel Allocation Techniques

FDM uses frequency division and channel allocation techniques to achieve multiplexing. Frequency division is the process of dividing the available spectrum into multiple non-overlapping sub-channels, ***mon frequency division methods include uniform frequency division and non-uniform frequency division.

In uniform frequency division, the spectrum is divided into multiple sub-channels with equal bandwidth. For example, a 10 MHz frequency band can be divided into 5 sub-channels with a bandwidth of 2 MHz each.

Non-uniform frequency division divides the spectrum into sub-channels with different bandwidths according to the bandwidth requirements of different signals. This method can more flexibly adapt to the needs of different signals.

Channel allocation is the process of assigning each sub-channel to the corresponding communication signal. Channel allocation can be based on different strategies, such as static allocation and dynamic allocation. Static allocation assigns fixed sub-channels to each communication signal at the system design stage, which does not change over time. Dynamic allocation assigns channels based on the real-time needs of communication signals in the system, maximizing spectral efficiency.

The application areas of FDM technology are extensive. The next chapter will introduce the specific applications of FDM in wireless communication.

# 3. Applications of FDM in Wireless Communication

In the field of wireless communication, Frequency Division Multiplexing (FDM) plays a significant role in various applications. By assigning different signal frequencies to different channels, multiple communication signals can be transmitted simultaneously in the same time and space. The following will introduce the specific applications of FDM in mobile commun