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Base stations (gNBs) generally deal with multiple mobile stations UEs, some of which require larger bandwidths than others and some of which have better connections (signal quality) than others. In ideal circumstances the base station has plenty of resources (e.g., bandwidth) and each UE gets the resources it needs. However, usually resources are limited, and the base station needs some way of fairly allocating the resources between the UEs. 

Consider the downlink of a single gNB 5G cellular system. Several UEs are receiving data from ongoing transfers, for example, TCP controlled file downloads. Assuming that the bottleneck on the transfer path for these connections is this gNB to UE wireless access, the downlink per-UE queues in the gNB will be nonempty. At the beginning of each downlink slot (TTI) the gNB scheduler has to decide which of the UEs’ waiting data to transmit in that slot. 

At each gNB the MAC scheduler decides the PRB allocation, per carrier, per TTI (slot), in the PDSCH (DL) and in the PUSCH (UL). Control packets such as the buffer status report (BSR) and UL assignment, are assumed to be sent out of band. The resources for transmission of these control packets are part of Overhead. This overhead fraction varies for UL and DL, across FR1 and FR2, and is provided in the standard. 

A LTENR Resource Allocation log can be generated as part of 5G simulations to understand the working MAC scheduler and resource allocation. However, if users wish to obtain a metrics table with resource allocation information provided on a per UE basis and on a per slice basis, follow the instructions provided below.

PRB metrics workspace download link: https://github.com/NetSim-TETCOS/LTENR_PRB_Metrics_v14.4/archive/refs/heads/main.zip

Follow the instructions specified in the following link to download and set up the Project in NetSim: https://support.tetcos.com/en/support/solutions/articles/14000128666-downloading-and-setting-upnetsim-fileexchange-projects

After downloading and importing the workspace, upon running any 5G simulation you can access resource allocation metrics from the Additional Metrics section of the Simulation Results dashboard, and scrolling to the bottom, as shown below:

The table comprises of information on allocation on a per gNB per UE, per channel, per carrier basis, providing total PRB's available for allocation at the gNB for the entire simulation duration and how much was allocated to a particular UE along with the allocation percentage. 

If network slicing is enabled in any of the gNB's in the network, then an additional metrics table showing slice specific resource allocation will appear as shown below:

The table comprises of information on allocation on a per gNB per slice, per channel, per carrier basis, providing total PRB's available for allocation at the gNB for the entire simulation duration and how much was allocated to a particular slice along with the UE's mapped to that particular slice, the slice type and the allocation percentage.

This data can also be exported to an excel csv file, by clicking on the Export Results button in the Simulation Results dashboard, as shown below:

Provided below are a few examples that explain how to correlate the metrics with the network configuraiton.

Consider the scenario below:

• 3 UEs placed at different distances connected to same gNB
• Downlink traffic from server to UEs
• Carrier Aggregation type is Single Band

After simulating this network scenario, the Resource Allocation metrics obtained are:

So, here we can see that we have logged metrics per each gNB, each UE for specific Channel and CC ID and on the right side we have the Allocation information as discussed before.

This metrics help us to know better about the allocated resources based on per UE (user device).

LTENR Slice Allocation Metrics

In the same way we also have LTENR Slice Allocation Metrics which helps users to know the resource allocation for the specific slice with specific channel and specific Component Carrier ID and to know which UEs are mapped to that specific slice and allocated PRB count along with allocated percentage.

Note: LTENR Slice Allocation Metrics is logged only when Slicing is set to True in UI

Consider the same scenario discussed above with Static slicing configured as:

• 80% for slice 1 mapped to UE 12 which is farthest
• 20% for slice 2 mapped to UE 10 and 11 

After simulating this network scenario, we obtain both Resource Allocation metrics and Slice Allocation metrics:

Here, in the Slice allocation metrics we can see that allocation percentage is 79.09% (approx. 80%) for Slice 1 and 19.46% (approx. 20%) for Slice 2.