Receiver sensitivity is the ability of the receiver to receive signals in the sense that any signal below the sensitivity is considered as noise and is not usable. Receiver sensitivity is given by S = Antenna Noise (dBm) + Receiver Noise Figure (dB) + C/N (dB) S = the receivers sensitivity C/N = Carrier to … Read more
Spatial multiplexing is where multiple independent streams are transmitted across multiple antennas. If the receiver also has multiple antennas, the streams can be separated out using spatial multiplexing. Instead of increasing diversity, multiple antennas in this case are used to increase the data rate or capacity of the system. In a rich multipath environment, the … Read more
Here I write Interference Margin in simple word and basic definition of interference margin in LTE. Let understands it. Interference margin accounts for the increase in the terminal noise level caused by the interference from other users. LTE uplink is orthogonal if it is within the same cell so there is no intra-cell interference. However, … Read more
Here I just review how TTI Bundling for LTE link budget first lets see what link budget feature overview. Features Overview Below is a quick summary of specific features and their corresponding impact on the radio network link budget result if the features or functionalities are deployed. TTI Bundling By repeating the same uplink information, … Read more
Power boosting in LTE is mainly perform on the Reference signal. However, since the radio power is shared equally by all Resources element, the power allocation for each RE is fixed. By increasing the number of Resources element being used as Reference Signal, the RS can be “boosted’ by 2x (3dB), 3x (4.7dB) or 4x … Read more
The concept of Interference Rejection Combining (IRC) is to regenerate the transmitted signal based on the estimated data from the previous receptions, emulate the distortion occurring from the multi-path channels and, finally subtract all regenerated interfering signals from the uplink received signals to obtain more reliable estimation of original users’ data. This feature utilizes the … Read more
Here I write about a simulation analysis of the system performance deterioration caused by the following four types of interference: eNodeB->UE, UE->eNodeB, eNodeB->eNodeB, and UE->UE when two systems share the eNodeBs. During simulation, it is assumed that the time percentage of the interference occurrence is 100%, that is, interference is always there. From simulation result … Read more
Absence of synchronization is one of the main sources of interference between TDD based systems belonging to different carriers. The figure below provides a quick view of what will happen if there is asynchronous situation between different networks. Scenarios (a) and (c) described below clearly indicate inter-carrier interference. Implementation of time synchronization equipment such as … Read more
It is difficult to separate Adjacent Channel Leakage power Ratio and Adjacent channel selectivity because they coexist. therefore, Adjacent Channel Leakage power Ratio and Adjacent channel selectivity are usually considered together. The result of the consideration is Adjacent Channel Interference Ratio (ACIR) and Adjacent Channel Interference Ratio is the ratio of the total power transmitted … Read more
Here I write about a simulation analysis of the system performance deterioration caused by the following four types of interference: eNodeB->UE, UE->eNodeB, eNodeB->eNodeB, and UE->UE when two systems are not co-located. From simulation result with no filtering, when the eNodeBs are not co-located, the most serious interference is from eNodeB->eNodeB. The network coverage and capacity … Read more