Re: [Discuss-gnuradio] Making new block with GRC or write python

[Hoang Ngo Khac]

Thank you Tom,

I've installed gr-mac and try on running some flow graph.

Some blocks there give output as message, but I want to take complex samples. How could I convert from message to complex?

I used Message Source for that purpose but this error appears:

NameError: global name 'blocks_message_soure_0_msgg_in' is not defined

Best,

Hoang

On Thu, Apr 24, 2014 at 8:42 PM, Tom Rondeau <address@hidden> wrote:

On Mon, Apr 21, 2014 at 4:47 AM, Hoang Ngo Khac <address@hidden> wrote:

Dear List,

To make my question on https://www.mail-archive.com/address@hidden/msg48001.html more clear, I would like to add more details.

I want to implement a bidirectional two-way relaying network using 3 USRPs and GNU Radio. The model is at attachment 1.
1st slot: Two end nodes (A, B) send information to relay node (R) in different frequencies. Relay node receives both and make a bitwise XOR mapping.

2nd slot: Relay node sends the XORed message to end nodes. Each end nodes performs another XOR on this message and its original message to extract information from other end node.

For time synchronization, the following protocol using a beacon added in relay node has been proposed:

Node A, B (see in attachment 2):

+ Wait for beacon

+ Receive beacon

+ Transmit message

+ Wait for message from relay
+ Receive message from relay

+ Restart

Node R (see in attachment 3):
+ Transmit the beacon
+ Wait for the two messages to be received,

+ Check for error
+ Combine the messages,
+ Transmit the combined message,
+ Restart

My question is should I make this process by making some new blocks in GRC or writing python script? In addition, how to tell a RX/TX chain to start/stop since these USRPs work in half-duplex mode?

Thank you so much.

Hoang

Take a look at gr-mac:

https://github.com/jmalsbury/gr-mac

It's all done in GRC and would be an appropriate starting point. GRC produces Python code, so you can always take that and work in Python when you get into a place with GRC that you can't do what you want.

Tom

 

--

Hoang Ngo-Khac

Vietnam National University, Hanoi (VNU-H) - Univ. of Engineering and Technology (UET)

Faculty of Electronics and Telecommunications (FET)

Alternative email:  address@hidden

Mobilephone:  +84.163.682.7874