Basic Uplink Throughput in LTE (FDD Case)


There has been a series of posts for LTE Throughput computation in both FDD and TDD. 

For TDD Case: You can find them


Today is the start of uplink throughput computation. The physical uplink shared Channel (PUSCH) is used to transfer application data. Your application data could be anything whatever you transfer from your phone......

Uplink throughput depends upon a number of factors such as

  • Resource Blocks allocated
  • Modulation scheme used
  • Coding rate and Redundancy used
  • Schemes such as MIMO or Carrier aggregation applied or not

Uplink throughput Dependencies

PUSCH is a shared channel, so the amount of resource blocks allocated to this channel depend upon the bandwidth of the channel, number of users, as well channel conditions in which users are standing. RF and Channel conditions will ultimately dictate the throughput the modulation scheme to be used. Users in good RF condition will get higher modulation scheme allocated while worst RF conditions will get lowest modulation schemes assigned and ultimately lowest throughput. 

In addition, Normal and Extended Cyclic prefix decides how much throughput can be achieved.  Extended Cyclic prefix will reduce the number of Single Carrier FDMA symbols in per 1 msec in Uplink subframe. 

In case of Normal Cyclic prefix you can have 14 SC-FDMA symbols in 1 msec subframe.

For Extended Cyclic prefix, you can have 12 SC-FDMA symbols in 1 msec subframe. 

Theoretical uplink throughput for normal cyclic prefix

Normal Cyclic Prefix: Non realistic throughput for FDD physical layer if all resources are allocated to PUSCH. Credit: LTE in Bullets

The theoretical throughput above are not achievable in practice but provide a starting point from which to derive the maximum expected throughput 

Theoretical uplink throughput for extended cyclic prefix

Extended Cyclic Prefix: Non realistic throughput for FDD physical layer if all resources are allocated to PUSCH. Credits: LTE in Bullets

Some important things to keep in mind for above computations are that the impact of MIMO is excluded from the above computations to focus upon the the maximum achievable throughput only as a starting point for comparison purposes. 

If you have any questions or just want to speak up your mind. Leave it in the comments below. 

  • How dou calculated Modulation Symbol Rate?

    • Azar says:

      In order to compute Modulation Symbol Rate. Do this (Resource Blocks) * (12 sub-carriers) *(OFDM symbols in 1 msec.) and then convert final answer into seconds.

      Thank you for the question.

  • >