Packet Communications: Difference between revisions
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<b>DRAFT</b> | <b>DRAFT (A Work in Progress)</b> | ||
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]] | ||
<hr> | |||
==== 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 === | === 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
- QPSK Modulation / Demodulation
- BPSK Demodulation
- Polymorphic Types (PMTs)
- Stream Tags
- Message Passing
- Understanding ZMQ Blocks
- Packet Communications
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:
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'