Re: [Discuss-gnuradio] Packet Header Generator and Stream CRC32

[zs]

Hi Martin,

Thank you.

1.Why the packet length should be larger than 32 bits?Can you explain it?

2.For example,I'm using the OFDM example in gnuradio.If i want to have a working CRC,I must set the length>=4?Is 4 OK?

3.Is the packet length means that the original length(for example len=a) or the length of data pass through CRC(len+4)?

Best regards,

zswx  

At 2015-07-11 07:40:38, "Martin Braun" <address@hidden> wrote:

On 10 Jul 2015 01:38, "zs" <address@hidden> wrote:
> If I want to have a working CRC,what is the number of packet length at least?

32 bits.

> If someone don't want to use the Stream CRC32 block,Packet Header Generator still will add the crc at bit 24-31.Is it right?I suggest the code should add a function to judge before add the crc at bit 24-31.

We don't want to overload this generator with options. The idea is you subclass the generator to tailor to your needs. See also the other generators.

> 3.For example,the OFDM example.If the transmitter don't add the crc32 block,whether the receiver will display the warning "Detected an invalid packet at item %1%"?

No, that's precisely why we have it. However, the payload also has a crc.

Cheers,
M