# Calculating throughput of BPSK channel with roll-off, error correction code, packet loss

A digital signal is transmitted with packets of:

240 bytes of information.
control header of 10 bytes.
reference signal of 700 μs/packet

BPSK modulation.
rolling factor of 0.25
1 MHz band.
coding rate of 3/4.
probability of packet loss of 10%.

What is the throughput rate?

My efforts so far:

Baud rate = (Band)/(1 + rolling factor) = (1 MHz)/(1.25) = 0.8 MBd
Bit rate = 0.8 MBd * 1 bit/symbol = 0.8 Mbps
Considering packet loss = 0.8 Mbps * (1-packet loss rate) = 0.72 Mbps
Useful bit rate = 0.72 Mbps * coding rate = 0.54 Mbps

I am struggling now on how to consider the pilot signal on the calculation... could anyone enlighten me and give me a hint on how can I complete this calculation?

thanks!

• Is packet loss after ECC? – Sunnyskyguy EE75 Jul 24 '18 at 15:00
• right, ECC after packet loss. just fixed. thanks, Tony! – Martin Horst Jul 24 '18 at 15:09

## 1 Answer

Raw Bit Rate Packet time BR*Nbits = 312.5 us
Packet interval = 700 us.

Perfect Thruput = 44.6%

• would you please explain what you meant by BR and Nbits? thanks! – Martin Horst Jul 24 '18 at 16:43