Investigating Latency in gnu software Radio with usrp embedded Series sdr platform

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Investigating Latency in
GNU Software Radio with USRP Embedded Series 
SDR Platform 
Nguyen B.Truong 
Division of ITCE, POSTECH 
Pohang, Gyeoungbuk-do, 790-785 South Korea 
[e-mail]
Chansu Yu 
Department of Electrical and Computer Engineering 
Cleveland State University 
Cleveland, OH 44115, U.S.A
[e-mail]
Abstract
—
 Software-Defined Radio (SDR) is a radio technology 
that most of conventional radio components are implemented in 
software. Besides the advantages like re-configurability and 
flexibility, a SDR system has to face a critical challenge on real-
time processing due to high jitter and latency. Thus, 
understanding latency in SDR systems is very important. This 
paper focuses on investigating the latency of a popular SDR 
platform - GNU Software Radio with a new Universal Software 
Radio Peripherals (USRP) device 
–
USRP Embedded Series E100. 
This research investigates and analyzes the reasons of the delays 
by considering all the buffering mechanisms in the platform. 
After that, we verify and quantify them by using three 
experimental methods. The first method is to calculate the whole 
delay of the SDR system by measuring the round-trip time 
(RTT). The second method measures subparts of the whole 
latency by using timestamp during a packet transmission process. 
The third approach is designated to measure the latency of the 
hardware part and bus communication part. We believe this 
study offers the better understanding of the latency in a new 
embedded USRP series 
–
 USRP E100 with GNU Software Radio