Spectral efficiency is simply the number of bits transmitted over a frequency bandwidth in a specific time and is measured in bits/s/Hz. It is proportional to throughput as the throughput is also bits per time transmitted in a certain bandwidth. If the number of bits transmitted in a subframe (time) over a specific number of Resource Blocks (frequency bandwidth) is high, then it will correspond to higher throughput and higher spectral efficiency. Alglocell automates spectral efficiency optimization utilizing various factors that impact spectral efficiency and 5G/4G throughput optimization.
– Signal to Noise & Interference Ratio:
The most basic and common factor that Aglocell utilizes to control spectral efficiency and throughput is SINR (Signal to Noise and Interference Ratio). If the SINR of a network is bad, then that puts a limit on the throughput gain that it can achieve. So, the first thing Aglocell verifies is the SINR of each cell in the network. Let’s check some of the factors that impact SINR
Sites that are too close to each other will have a higher tendency to interfere with each other and will require aggressive down-tilts to limit overshooting. The distance is something that is usually fixed as 5G/4G sites mostly use the previously deployed network. So, Aglocell utilizes AI-driven image classification algorithms to detect if cells are overshooting and downtilts to improve SINR and reduce overshooting.
• Electrical Tilt Ports: It is better to use antennas that assign a different RET port (electrical tilt) to 4G and 5G. That provides flexibility for optimization. If the network uses the same RET port for 4G and 5G then any change on LTE tilt will impact the other RAT and it takes away the flexibility. So, it is a good idea to keep this in mind in the design or expansion phase.
• Pa & Pb: Another parameter Aglocell utilizes in the case of smaller inter-site distance is to use a more balanced RS power (Reference Signal). When the inter-site distance is low, then high reference signal power can result in higher interference. If the inter-site distance is large then Aglocell utilizes this parameter as a 3dB Reference Signal boost that improves coverage as coverage is controlled with RSRP and RSRP is the direct outcome of RS power. However, in the case of small inter-site distance, Pb and Pa values of 0 might provide a more optimized solution as in this case, the RS power will not be boosted compared to the PDSCH symbols.
Load & Utilization
Another factor is the load in the area or cluster. Higher the load, the higher the interference to the neighboring cells. As the load increases, the power per Resource Element increases which will result in higher aggregate power in the area increasing the RSSI. For neighboring cells, such power is considered interference. So, if the load increases above a threshold, then Aglocell offloads the congested carrier and shifts the load to an uncongested carrier. Aglocell tunes cell reselection or mobility parameters to optimize load.
Sometimes, Aglocell has found the actual traffic volume is not that high but the utilization of the cell is still very high. This is usually caused due to low signal quality as the users with bad SINR will take a lot RBs at a lower modulation. In this case, when the traffic is not high but utilization is still high Aglocell optimizes SINR.
Aglocell utilizes AI-driven algorithms to improve spectral efficiency up to 19.5% or more by automating the optimization of numerous factors that affect spectral efficiency including the above mention factors.
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