Re: [Discuss-gnuradio] tx_ofdm

[Martin Braun]

On 05/22/2014 10:12 PM, eontool wrote:
> IIRC,  the tx and rx files are just a very general implementation of the OFDM
> model.
> 
> Here's my understanding:
> 
> - Packet length refers to the data necessary to produce n symbols (48 data
> carriers, 2 symbols = 96).

Er, no. This is the number of bytes per packet. It's 96 because we add 4
bytes for CRC, and then the packet number is a round value.

At 100 bytes per packet, the payload is 800 bits. With BPSK, that would
be 17 OFDM symbols (plus 1 OFDM symbol for header, and 2 for preamble).

You can set whatever here, but remember that the stock equalizers don't
do a good job on long packets. Also, the length can vary per packet.

> - The number of total carriers in the systems equals the FFT length.
> In this case, 48 data carriers and 4 pilots, 52 total and the rest are set
> to 0.

This is correct (compare 802.11a standard).

M