2016 WNFA LAB2

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Mobile and Vehicular Network Lab

2016 WNFA LAB2

Yu-Lin Wei 2016.3.25

USRP

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Outline

• Intro

– USRP

– Environment

• TODO

– Transmitter – Receiver

– Decoding

• Grading Criteria

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Intro

What is USRP

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• Universal Software Defined Radio

– Expensive !

– Use C++/ python/ GUI to define the radio !!

• Official document

– https://www.ettus.com/content/files/07495_Ettus

_N200-210_DS_Flyer_HR.pdf

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Ethernet to PC

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• UHD

– USRP Hardware Driver – C++ API

– http://files.ettus.com/manual/

– https://github.com/EttusResearch/uhd

• UHD tool

– uhd_find_devices

• This program scans the network for supported devices

and prints out a list of discovered devices and their IP

addresses.

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– uhd_usrp_probe

• This program constructs an instance of the device and prints out its properties, such as detected

daughterboards, frequency range, gain ranges,

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• How to compile

– File Directory

• Use built in Make file

• uhd/host/examples

• Put your files here

• Add your files in the Cmakelist.txt

– Compile Directory

• uhd/host/build/examples

• make

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Intro

Environment

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• Last year…..

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• System in LAB

• Access through ssh ( test your single_tx/

single_rx)

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• ssh wnfa_16_[#]@10.5.6.202

– E.g. wnfa_16_01@10.5.6.202

• HW code put in ~/uhd/host/example

– single_tx.cpp – single_rx.cpp

• cd ~/uhd/host/build

• cmake .. (only the first time

• make

• cd example ( now in ~/uhd/host/build/example

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• mkdir wn_trace

• put your src_data_1.bin here! ( transmitted by Tx

• Transimitter :

– ./single_tx --f=2.49 --i=128

• Receiver:

– ./single_rx --f=2.49 --i=128

• Received data in ./wn_trace/recv_signal.bin

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Working Flow : (wn_lab2

• Run program/matlab/singal_generator.m

• Get src_data_1.bin / src_data_1.mat in program/trace

• Upload src_data_1.bin to wnfa_16_[#]account

• ~/uhd/host/build/example/wn_trace

• run ./single_tx ./single_rx under

~/uhd/host/build/example

• Download …example/wn_trace/recv_signal.bi

n

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• Put recv_signal.bin in program/trace

• Run program/decode.m to get the plot

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TODO

Tx / Rx

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• Tx ( single_tx.cpp)

– Given data array, transmit it

• Rx ( single_rx.cpp)

– Implement receiving function

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TODO

Decoding -

MATLAB

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• Decode.m

– CFO correction – Packet detection – Phase Track

– Calculate SNR

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• Figure 1 : Raw

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• Figure 2: Preamble Channel

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• Figure 3 : subcarrier estimation

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• Figure 4 : phase shift animation

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• Figure 5 : subcarrier SNR ( may be different )

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• Figure 6 : symbol SNR ( may be different )

•

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• Figure 7 : constellation

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Grading Criteria

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• Tx : 15%

• Rx : 15%

– If only either of them work, judge by if can work w/ TA version Tx/ Rx

• MATLAB

– Figure 2-3 : 5%

– Figure 4-7: 10%

• Report

– 10%

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• Deadline:4/26(Tue.) 23:59 email to wn@csie.ntu.edu.tw – Email subject:[WN]lab2_teamXX

– [WN]lab2_teamXX.zip

• source code(single_tx.cpp/ single_rx.cpp/ decode.m phaseTrack.m pkt_detection.m)

• Report(.pdf)

• Demo-4/26(Tue.)

– Please register the demo slot. And come to CSIE R424 at that time. (TBA)

– All you should do are :

• Run the working flow in p15

Grading Criteria

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特別評分機制

• 90% Lab 團體成績 (由各個作業負責的助教決定)

• 10% 小組互評成績

– 匿名

– 給分範圍為 -2.5 ~ 2.5

– 給分總和需等於 0 (ex 0.25/0.25/-0.25/-0.25)

• 目的

– Report 上的工作分配有時無法準確的表達各個組員各自的想法，因此添加此機制作參考

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• Contact to TAs :

– facebook

https://www.facebook.com/groups/wn15spring/

– Email : wn@csie.ntu.edu.tw

– Office hour : Tue. 13:20~14:10/TBA

@ CSIE R424

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