top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

How to calculate the data rate in UE and eNodeB?

+2 votes
539 views

Assume we have UE and eNodeB stacks are there and through smartbits we are pumping both UL&DL data.
How to calculate the data rate in UE and eNodeB?

posted Jun 19, 2014 by Kuldeep Apte

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button

1 Answer

0 votes

In order to get a raw peak data rate at the PHY layer e.g. in the DL you do the following:

  1. Assume we have 20MHz band, so the number of PRBs in the frequency domain is: PRBno = 100
  2. Assume we have 1 OFDM symbol for control region (for PHICH, PCFICH and PDCCH) in each subframe, so number of OFDM symbols per subframe for user plane data (PDSCH) is: NoOFDMSymbols = 13 (for normal CP)
  3. Assume we have SISO case (one antenna), so the number of Cell RS for the PDSCH per 2PRBs is: NoRS = 6
  4. The number of subcarriers per PRB is: NoSubcarriers = 12
  5. The number of RE (resource elements) available for carrying PDSCH per 2PRBs is: NoREs = NoOFDMSymbols * NoSubcarriers – NoRS = 13 * 12 – 6 = 150
  6. The number of REs for subframe is: NoREPDSCH = NoREs * PRBno = 150 * 100 = 15000
  7. For peak datarate we use 64QAM, which gives the number of bits per RE: bitsRE = 6
  8. The number of bits for the whole subframe is: NoBitsPDSCH = NoREPDSCH * bitsRE = 15000 * 6 = 90 000
  9. The number of subframes in one sec is: NoSFs = 1000 [SFs/Sec]
  10. The max throughput then (raw, ie. without FEC) is: RawThrpt = NoBitsPDSCH [bits/SF] * NoSFs [SFs/Sec] = 90 000 * 1000 = 90 000 000 bits/sec = 90 Mbits/s
  11. If you add then the typical FEC rate for good channel conditions of: FECrate = 5/6
  12. You end up at: PHYThrpt = RawThrpt * FECrate = 90 Mbits/s * 5/6 = 75Mbit/s

So that’s your thrpt for DL at PHY. Then additionally you need to get out of it some % for RRC signalling and system info, and overhead of MAC/RLC/PDCP and TCP/IP stack.

For UL, the situation is similiar, but you need to take into account the typical UL frame PHY overhead (DRS, SRS, PUCCH, PRACH)

answer Jun 20, 2014 by Dilbagh
Similar Questions
+2 votes

As for uplink resources we know we need to know before that how much data UE has to send and how much is in buffer. That is ok but how can we predict the data rate for that data?

0 votes

What is the range of RSRP, RSRQ, RSSI and SINR value to get good data rate and how it is related to eNodeB transmition power ? And how these values are used at UE ?

+2 votes

This is not a usual case. Assume an eNodeB has multiple bearers (GBR and non-GBR) with the UE, eNodeB enforces subscribed downlink data rate by using the different scheduling algorithm. Can eNodeB reject the uplink grant assuming UE is crossing its subscribed limit ?

+4 votes

In India we follow 2400 MHz for LTE frequency where other countries have LTE on 600-800 MHz? Does it lead to higher data rate?

...