Based on the frequency band: Uplink interference and Downlink Interference
Uplink interference can be defined as interference in the uplink frequency range of the mobile network and interference from an external radio frequency source to the base stations. Uplink interference can reduce coverage at the base station. If there is no uplink interfere, the base station can still receive mobile phones signals from faraway locations. Uplink interference is when the base station receives a mobile phone signal that is stronger than the interference. Mobile phones must be located closer to the base station in order to communicate with them. Signal Jammer
Downlink interference refers to an interference signal that is sent by an interference source in the downlink frequency spectrum of the mobile networks. If the interference signal is detected in the downlink frequency bands of the mobile networks, the mobile phones cannot distinguish the normal base stations signal. Communication between the mobile phones and the base stations is disrupted, leading to dropped calls or registration failures.
The interference of unwanted signals at the same frequency and the useful signal within the receiver’s passband is called co-channel interfere. These unwanted signals are identical to useful signals. They are converted to frequency by the receiver to be within the intermediate frequency passband. As long as interference is occurring at the receiver input, it cannot be filtered or suppressed by the receiver system.
Non-cochannel interference includes intermodulation interference (blocking interference), adjacent frequency interference, spurious interference, and intermodulation interference.
adjacent channel interference
Refers to interference caused by signal from frequencies adjacent the applied signal frequency. An unsatisfactory receiver filter can lead to adjacent frequency interference. The signal from the adjacent frequency will leak into the transmission bandwidth. You can reduce interference by channel assignment and precise filtering.
Near-far effect: A base station transmitting in a very close range to the receiver will cause serious problems. The receiver then uses the signal from the base station for the preset channel. Near-far effect can also be caused by channels that are very close to a base station or a weak signal mobile channel. Because all mobile stations use the same frequency bands, the effect from the near-far effects is stronger in the UMTS. However, the UMTS uses great power control to eliminate this effect.
If two or more frequencies are acting on a circuit nonlinear, they will interact to create a new frequency output. Intermodulation interference occurs when the frequency is outside the operating channel bandwidth. .
A receiver’s reception dynamic range is a limit. If the out-of band interference signal exceeds a certain level and the receiver is fully blocked, the system’s reception performance will be affected. Jamming refers to interference that is not in the receiver’s frequency range. A blockage can cause the receiver machine to stop functioning normally. Long-term blockage could also lead to permanent performance degradation.
Because of its roll-off characteristics, transmit filters are not ideal steps.
Therefore, out-of band radiation is an inevitable result. This is known as emission spurs. The interference caused due to transmission spurs can be called spurious interference.
Interference between mobile communication networks
In-band interference: The CDMA transmitting signals directly act on the GSM radio receiver as in band noise via methods such intermodulation. This results in a decrease the GSM receiver’s sensitivities. This type of interference can also be divided into transmitted spurious and intermodulation.
Out-ofband interference: If out-ofband interference is severe, it can cause receivers to become fully blocked. This will affect the GSM reception function. This is also known blocking interference.