In order to upload your pictures, videos, sending emails or what not. You need to have good amount of Uplink throughput available for LTE.
This brings the question what kind of throughput ( Realistically ) can you achieve in LTE Uplink?
What can cause uplink throughput to reduce?
In theory we can spend days and night in order to compute the Uplink Throughput for LTE Advanced as it has been done over here, but the real question do you actual see those theoretical values in the field as well or not?
Today we are going to discuss what can cause throughput to be lower than theoretical value. Few of the reasons are given below:
RRC Signaling is transferred using the Physical Uplink Shared Channel (PUSCH) and this reduces the PUSCH capacity available for application. The actual overhead depends upon the quantity of traffic but usually signaling traffic is relatively small.
Retransmissions reduce higher layer throughput. For example Hybrid Automatic Repeat Request (HARQ) reduce throughput above MAC layer.
Automatic Repeat Request (ARQ) re-transmissions from Radio Link Control (RLC) layer reduce throughput measured from above RLC layer.
If you use TCP, then similarly TCP retransmissions reduce the throughput measured from above TCP layer.
Protocol stack headers: Protocol stack headers also reduce the higher layer throughput. For example MAC, RLC PDCP and IP layer add headers to application data.
Miscellaneous: I am leaving Miscellaneous reason space left out for you. So that you can fill out the reasons you think can cause Uplink throughput to be reduced. You can list your reasons in the comments below.
uplink throughput for normal cyclic prefix
The Uplink throughput values for Normal Cyclic Prefix are as follows:
- Presented for Coding rate of 0.75
- Coding rate of 0.95 is only shown for 64 QAM modulation scheme
- The values are applicable (assume) 2 ms PRACH preamble per radio frame.
- 10% retransmission rate
- 5% Overhead on account of RRC signaling and protocol headers
uplink throughput for EXTENDED cyclic prefix
The assumptions presented for Normal Cyclic Prefix scenario above are the same for Extended cyclic prefix.
UL Throughput values for Extended cyclic prefix are shown below.
realistic ul throughput in case of mimo (Normal cyclic prefix)
In order to see how much difference it will make in Uplink Throughput in case of MIMO, then you can take a look at the table below.
The throughput values shown below in the table have taken into account the following:
- Various Overheads: Such as Demodulated Reference Signals for PUCCH, Demodulated Reference Signals for PUSCH
- Retransmissions: 10% HARQ retransmission rate
- Additional 5% overhead generated by a combination of RRC signaling and protocol stack headers
The values shown above for the case of MIMO are double or 4 times compared to non-MIMO scenario.
Additional assumption about the UL MIMO throughput is that each Component Carrier has the same configuration so the throughput increase is in direct proportion to the number of RF carriers.
The values for throughput shown in the tables are peak connection throughputs not average cell throughput.
The throughput values shown above is not an exhaustive list of all the throughput values you can achieve in practice. The scenarios described are limited for specific scenario only. However, the table gives you an idea what peak values can you expect in Uplink in caes of FDD.
Please leave your comments below 🙂