SOR Spectrum Overshooting Ratio

SOR, or Spectrum Overshooting Ratio, is a metric used in telecommunications to evaluate the performance of a digital communication system, particularly in wireless and mobile networks. It quantifies the level of interference or overlapping between adjacent frequency channels within a system.

In a digital communication system, such as a cellular network, the available frequency spectrum is divided into multiple channels, each allocated to different users or services. These channels are separated by a guard band or a specific frequency gap to minimize interference between them. However, due to various factors such as imperfect filters or signal propagation characteristics, some degree of spectral leakage or overshooting may occur, causing interference and degradation of signal quality.

The Spectrum Overshooting Ratio (SOR) measures the extent of this overshooting or interference by comparing the power level of the main lobe of the signal with the power level of the side lobes that leak into adjacent channels. It is expressed as a ratio and is typically represented in logarithmic units, such as decibels (dB).

To calculate the SOR, the power levels of the main lobe and the side lobes are determined. The main lobe corresponds to the desired signal power within the assigned channel, while the side lobes represent the undesired power leaking into neighboring channels. The SOR is then calculated as the ratio of the side lobe power to the main lobe power, often expressed in decibels:

SOR (dB) = 10 * log10 (Side lobe power / Main lobe power)

A higher SOR value indicates a higher level of interference or overshooting, meaning that the adjacent channels are more likely to experience interference from the main signal. On the other hand, a lower SOR value indicates better spectral containment, with minimal leakage into neighboring channels.

Telecommunication standards and regulations often define acceptable limits for the SOR to ensure efficient and interference-free operation of digital communication systems. By monitoring and optimizing the SOR, network operators can mitigate interference issues, improve signal quality, and enhance the overall performance of the communication system.

It is important to note that SOR is just one of several metrics used to evaluate the spectral characteristics of a digital communication system. Other metrics, such as adjacent channel power ratio (ACPR) and adjacent channel leakage ratio (ACLR), are also commonly used to assess the system's ability to contain and minimize interference between adjacent channels.