BER, BLER, and FER
Ram Prakash Singh
Could anybody explain what are BER (Bit Error Rate), BLER (Block Error
Rate) and FER (Frame Error Rate), I mean how are they calculated ?
Regards,
RPSing
Mandeep Kumar Ral
If you are interested in knowing the exact methods of calculation of
the variables. You may have to read several physical layer documents.
I suggest, to start with, you see 25.225 (for TDD) and 25.215 (for
FDD). In case you are only trying to get some idea of these terms
following explanation(taken from above mentioned specs) should be
suffice. Following explanation applies for FDD only.
Transport channel BLER
The BLER estimation shall be based on evaluating the CRC on each
transport block after RL combination. BLER estimation is only required
for transport channels using CRC. In case of no TFCI is used all
transport formats of a transport channel shall use CRC to enable BLER
estimation for this transport channel. In connected mode the BLER
shall be possible to measure on any transport channel. If requested in
idle mode it shall be possible to measure the BLER on transport
channel PCH.
Note that one transport block contains one MAC-PDU only.This is
normally used to give RNC(by node-B) feedback about the link. So that
RNC can adjust target SIR.
Transport channel BER
The transport channel BER is an estimation of the average bit error
rate (BER) of the DPDCH data of a Radio Link Set. The transport
channel (TrCH) BER is measured from the data considering only
non-punctured bits at the input of the channel decoder in Node B. It
shall be possible to report an estimate of the transport channel BER
for a TrCH after the end of each TTI of the TrCH. The reported TrCH
BER shall be an estimate of the BER during the latest TTI for that
TrCH. Transport channel BER is only required to be reported for TrCHs
that are channel coded.
Physical channel BER
The Physical channel BER is an estimation of the average bit error
rate (BER) on the DPCCH of a Radio Link Set. An estimate of the
Physical channel BER shall be possible to be reported after the end of
each TTI of any of the transferred TrCHs. The reported physical
channel BER shall be an estimate of the BER averaged over the latest
TTI of the respective TrCH.
Following two terms may be worth looking as they are also related to
the topic
SIR
Signal to Interference Ratio, is defined as: (RSCP/ISCP) x SF.
Measurement shall be performed on the DPCCH of a Radio Link Set. In
compressed mode the SIR shall not be measured in the transmission gap.
The reference point for the SIR measurements shall be the Rx antenna
connector.
where:
RSCP = Received Signal Code Power, unbiased measurement of the
received power on one code.
ISCP = Interference Signal Code Power, the interference on the
received signal.
SF=The spreading factor used on the DPCCH.
SIR-error
SIRerror = SIR – SIRtarget_ave,
where:
SIR = the SIR measured by UTRAN given in dB.
SIRtarget_ave = the SIRtarget averaged over the same time period as
the SIR used in the SIRerror calculation.
About FER i reckon that it is a loose term i have seen it to be
used some specs but it is not present in actual measurements
parameters of physical layer. What physical layer measure is BER for
physical channels.
Mandeep
www.usigworld.com
rampraka...@wipro.com (Ram Prakash Singh) wrote in message news:<4c1b2165.01101...@posting.google.com>...