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FPC (Fractional Power Control)

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Introduction:

In wireless communication systems, the power control is one of the crucial techniques to ensure reliable communication with good quality and minimum interference. The power control techniques can be categorized into two types: fixed power control and variable power control. In fixed power control, the transmit power remains constant, while in variable power control, the transmit power is dynamically adjusted based on the channel conditions. Fractional Power Control (FPC) is a type of variable power control technique that is widely used in wireless communication systems.

In this article, we will discuss the concept of FPC, its advantages, and its applications.

What is FPC?

FPC is a type of variable power control technique that adjusts the transmit power in a fractional manner based on the channel quality. The channel quality can be measured using different metrics such as signal-to-noise ratio (SNR), received signal strength indicator (RSSI), and bit error rate (BER).

The main idea behind FPC is to adjust the transmit power in small steps rather than large steps. In FPC, the transmit power is adjusted by a small fraction of the total power, which is usually less than 1 dB. The fraction used for power adjustment is determined based on the channel quality. For example, if the channel quality is good, a small fraction is used to increase the transmit power, while if the channel quality is poor, a larger fraction is used to decrease the transmit power.

Advantages of FPC:

  1. Reduced interference: FPC helps in reducing the interference caused by a high transmit power. As the transmit power is adjusted based on the channel quality, it ensures that the interference is kept to a minimum.
  2. Increased capacity: FPC helps in increasing the capacity of the wireless communication system. As the transmit power is adjusted based on the channel quality, it ensures that the resources are optimally utilized, leading to an increase in the capacity of the system.
  3. Improved coverage: FPC helps in improving the coverage of the wireless communication system. As the transmit power is adjusted based on the channel quality, it ensures that the signal strength is maintained at an optimal level, leading to an improvement in the coverage of the system.
  4. Energy efficiency: FPC helps in improving the energy efficiency of the wireless communication system. As the transmit power is adjusted based on the channel quality, it ensures that the power consumption is optimized, leading to an improvement in the energy efficiency of the system.

Applications of FPC:

  1. Cellular networks: FPC is widely used in cellular networks to adjust the transmit power of the base station based on the channel quality. As the channel conditions vary with time and location, FPC helps in ensuring that the resources are optimally utilized, leading to an increase in the capacity and coverage of the cellular network.
  2. Wireless LANs: FPC is also used in wireless LANs to adjust the transmit power of the access point based on the channel quality. As the number of users and the channel conditions vary with time, FPC helps in ensuring that the resources are optimally utilized, leading to an increase in the capacity and coverage of the wireless LAN.
  3. Satellite communication: FPC is used in satellite communication to adjust the transmit power of the satellite based on the link quality. As the link quality varies with time and location, FPC helps in ensuring that the resources are optimally utilized, leading to an improvement in the coverage and reliability of the satellite communication system.

Conclusion:

FPC is a type of variable power control technique that adjusts the transmit power in a fractional manner based on the channel quality. FPC has several advantages such as reduced interference, increased capacity, improved coverage, and energy efficiency. FPC is widely used in different wireless communication systems such as cellular networks, wireless LANs, and satellite communication. FPC is also used in other wireless communication systems such as ad hoc networks, sensor networks, and cognitive radio networks. FPC helps in optimizing the power consumption, reducing the interference, and improving the performance of these wireless communication systems.

In FPC, the power adjustment is based on the feedback received from the receiver. The feedback can be in the form of a control signal that indicates the channel quality or a signal that indicates the received signal strength. The power adjustment is performed using a power control algorithm that determines the fraction to be used for power adjustment based on the feedback received from the receiver.