• • • • • • • • • • • In a linear system there will be two output frequency signals in the case of two input frequency signals. عغففتنتتت • In a non-linear system new frequency signals are generated in the case of one input frequency signal, we will have Harmonics. • In a non-linear system new frequency signals are generated in the case of two input frequency signals. • The new frequency signals are known as intermodulation products and this phenomenon is called intermodulation. عغففتنتتت DC Fundamental Second Harmonic عغففتنتتت Third Harmonic عغففتنتتت • The central frequency of the intermodulation product is expressed by the following formula: fM = mf1± nf2 • The order of intermodulation products is the order m+n عغففتنتتت عغففتنتتت عغففتنتتت • Multi-carrier co-transmt; • The antenna system has nonlinear passive components. • The intermodulation product falls into the receiving band of the carrier. • The level of the intermodulation product falling into the receiving band of the carrier is large enough. عغففتنتتت 1. Channel PIM • Contaminated surfaces or contacts due to dirt, dust, moisture, or oxidation. • Mechanical joints are loose due to insufficient torque, poor alignment, or inadequate contact surface preparation. • The mechanical joint is loose and causes shock or vibration during transportation. • The metal or shavings inside the RF connection. • In the preparation process, the hollow inner conductor with oval shape is over-enlarged or made. • Different metals in direct contact. • Immediate metallic objects in the direct beam and side lobes of the transmitting antenna, including rusted bolts, roof flashes, vent pipes, pull wires, etc 2. Spatial PIM • The AAU and passive antennas are installed too close. • The main lobes of AAUs and antennas overlap, which affect each other. • To prevent the PIM from being radiated from space, the installation suggestions are as follows: Horizontal installation distance (edge-to-edge) > 500 mm Vertical installation, the value is greater than 500 mm. عغففتنتتت • In below case, PIM interference is generated because the antenna side lobe radiates to the rear of the AAU. عغففتنتتت • Assume that PIM interference signals generated during downlink scheduling fall within the uplink frequency-domain range of a cell. • Therefore, it affects the uplink network performance of the cell. عغففتنتتت Hardware Check Method PIM Master عغففتنتتت عغففتنتتت • To mitigate the impact of PIM interference on the network, Huawei provides the intelligent PIM interference avoidance solution. عغففتنتتت عغففتنتتت During uplink scheduling in a victim cell the non-interfered RBs are preferentially selected for scheduling based on detected frequency-domain positions of interfered RBs. This reduced the frequency- domain range of PIM interference. عغففتنتتت This function calculates the frequency- domain positions of RBs that cannot be used for downlink scheduling of interfering cells and avoids these RBs as much as possible during downlink scheduling to reduce the frequency–domain range where PIM interference occurs. عغففتنتتت The downlink power reduction function takes effect in the interfering cells to reduce the strength of PIM interference. This function directly reduces the downlink transmit power of interfering cells. عغففتنتتت It is recommended that channel isolation for PIM interference avoidance be enabled when uplink KPIs significantly deteriorate and the uplink becomes basically unavailable due to strong uplink PIM interference. In this case the transmit channels specific to different carriers can be isolated to mitigate PIM interference. • For 4T4R cells the number of downlink channels of two carriers sharing the same channels is reduced from 4 to 2 • For 8T8R cells the number of downlink channels of the two carriers sharing the same channels is reduced from 8 to 4. عغففتنتتت Before Frequency and Bandwidth change 3rd Order Product عغففتنتتت Note: As frequency range in this tool can be select just by specific blocks it may not have accurate results, it calculate whole block frequency ranges. Before Frequency and Bandwidth change 5th Order Product Note: As frequency range in this tool can be select just by specific blocks it may not have accurate results, it calculate whole block frequency ranges. عغففتنتتت After Frequency and Bandwidth change 5th Order Product Note: As frequency range in this tool can be select just by specific blocks it may not have accurate results, it calculate whole block frequency ranges. عغففتنتتت • عغففتنتتت • Frequency and BW change Date: 1st Nov-2023 عغففتنتتت • Frequency and BW change Date: 4th Nov-2023 عغففتنتتت • Frequency and BW change Date: 5th Nov-2023 عغففتنتتت • Frequency and BW change Date: 5th Nov-2023 عغففتنتتت Thank You