Modelling LTE downlink capacity

[pedropumpalot]

Hi all,

I wish to model the LTE resources that impact the downlink capacity of cell in my LTE network, this will be used in a forecasting tool to predict when the average user download speed will be below xMbps.

Can anyone provide a comprehensive list of KPIs that I should measure as inputs to my model?

I work as a design engineer (physical configuration) and am not very up to speed on the physical/logical channels that impact DL throughput.

Any help would be greatly appreciated.

Thanks,

Pedro

[oswe]

you should talk with planning people. they do this math when they calculate #sites, they take some assumptions about user throughput that influence Transmission network capacity , baseband eNodeB capacity and for certain RF considerations, number of sites.
many networks suffer more in transmission network than in planning/capacity process

[RF engineer]

May be below will help.

Offered DL User Throughput = PRB Load * LTE Cell Capacity / TTI Load

Where
 LTE Cell Capacity [Mbps] = Number of PDSCH REs/sec*Bits per symbols*MIMO Gain*(1 –
BLER)

Assuming:
 MIMO Rank = 1.7 (2x2 MIMO)
 MIMO Rank = 3.1 (4x4 MIMO)
 BLER = 10%
 PRB Load = 85%
 TTI Load = 350% (3.5 users scheduled)

[rimeka]

you can consider also following kpi for input of your DL throughput model :
- Inter Site Distance (ISD). ISD less than 500m usually better throughput than more than 2000m
- Cell Bandwidth. Different DL throughput for 5 MHz, 10 MHz, 15 MHz, 20 MHz.
- Number of antenna (MIMO 2x2, 4x4, SISO),
- Number of RRC user
- PRB Utilization
- feature activated : such as DL 256QAM, Carrier Aggregation is also impact to throughput model.