Difference between revisions of "Packet Communications"

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<b>DRAFT</b>
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<b>DRAFT (A Work in Progress)</b>
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This tutorial presents methods to transmit and receive packet data using burst transmissions. The data can originate from a message source or a stream source. A hardware implementation is shown using BPSK modulation.
  
 
== Prerequisites ==
 
== Prerequisites ==
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[[File:Pkt_7_base_fg.png|800px]]
 
[[File:Pkt_7_base_fg.png|800px]]
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<hr>
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==== Message Strobe ====
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For the Message Strobe to generate a PDU, the Message PMT must be of the form
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  pmt.cons(pmt.PMT_NIL,pmt.init_u8vector(9,(71,78,85,32,82,97,100,105,111)))
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This specific vector has a length of 9 and the character values of "GNU Radio".
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==== Variable, Id: hdr_format ====
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The Protocol Formatter uses a Format Object to define its parameters. The one used in this example is
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  hdr_format digital.header_format_crc(len_key, num_key)
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==== Protocol Formatter ====
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The entry for the Format Obj. is 'hdr_format'
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==== Protocol Parser ====
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The entry for the Format Obj. is 'hdr_format'
  
 
=== Testing ===
 
=== Testing ===

Revision as of 10:14, 9 October 2021

DRAFT (A Work in Progress)

This tutorial presents methods to transmit and receive packet data using burst transmissions. The data can originate from a message source or a stream source. A hardware implementation is shown using BPSK modulation.

Prerequisites

Simulating Baseband Packet Processing

In order to grasp the basics of packet processing, this section presents a transmitter and receiver without any modulation or channel impairments.

Building the flowgraph

Build the following flowgraph using the details given below:

Pkt 7 base fg.png


Message Strobe

For the Message Strobe to generate a PDU, the Message PMT must be of the form

 pmt.cons(pmt.PMT_NIL,pmt.init_u8vector(9,(71,78,85,32,82,97,100,105,111)))

This specific vector has a length of 9 and the character values of "GNU Radio".

Variable, Id: hdr_format

The Protocol Formatter uses a Format Object to define its parameters. The one used in this example is

 hdr_format digital.header_format_crc(len_key, num_key)

Protocol Formatter

The entry for the Format Obj. is 'hdr_format'

Protocol Parser

The entry for the Format Obj. is 'hdr_format'

Testing

Using BPSK and Hardware

Transmitting a Signal

Receiving a Signal