Frequently Asked QuestionsBefore contacting us, please browse our FAQ.
Why should you or anybody care about SDR ?
- Over 93% of the mobile infrastructure market utilizes SDR technology, and future growth to support mobile data demand will simply drive more SDR base stations
- Almost 1 billion software defined radios have been shipped in 2011 for mobile terminal applications
- Virtually all of the tactical radios sold for military communications utilize SDR technology today
- Technology Road Map
Where to start?
If you’re coming from a programming background and you already know C++ and Python, you can directly start off with the signal processing. Even if you know only C++, you can get started with Python pretty quickly. The following then may be a good starting order for you:
- Digital Signal Processing (DSP): starting with the basics of signals & systems, sampling, filters and so on. “Understanding Digital Signal Processing” by Richard Lyons is a good reference, but you can try starting off with the free online book at http://www.dspguide.com/,
- Digital Communications: DSP principles as applied to communications: filters, modulation, demodulation, coding, noise, interference etc. The http://www.complextoreal.com/tutorial.htm tutorials provide a relatively very brief but decent overview.
- Software Radio in General: once you understand the previous two sections, you’ll see that most signal processing can be implemented as algorithms on a stream of numbers. The details of Software Radio may then be intuitive to you as a programmer.
What is compatibility to MATLAB ?
We provide functions to completely control SDR. We also provide source and sink blocks for Matlab Simulink. So one does not have to learn a new language. Existing simulations and work in Matlab can be directly ported to the hardware.
Why Linux for development?
# Ideal for resource-intensive environment, from data mining to large-scale financial modeling to SDR data piping.
# Development environments can easily be set-up for any open-source technology.
# The broadest and best development tools and libraries, all accessed easily from within the OS.
# The fastest route from development to deployment on desktop, mobile, server or cloud.
# The desktop of choice for developers at some of the world’s leading technology companies.
# Lightweight enough to install natively, yet efficient enough to enable you to get the most out of hardware.
# Certified to run on a wide range of hardware from the biggest brands in the industry.
# Enterprise systems management and support available directly.
Why Open Source ?
Imagine if everything we’ve learned throughout history was kept hidden or its use was restricted to only those who are willing to pay for it.
- Development driven by a wide range of contributors from commercial IT vendors, including original equipment manufacturers (OEMs) and independent software vendors (ISVs), to customers, academia, and government.
- Contributors who collaborate to define, design, and implement software that meets their needs.
- Lower costs because development is amortized across contributors.
- Open standards, which reduce vendor lock-in.
- Licenses that give free access to the code.
Advantages of mixed FPGA-CPU design ?
FPGA is very good at parallel computing and high speed logical operations. FPGA reduces PC CPU usage and improves processing of upper layer protocols L2, L3 and above. These protocols are better suited for RISC architecture of PC’s. Low volume prototyping is low cost on FPGA as high volume would use ASIC PHY chips. Bandwidth and latency of USB 3.0 link between FPGA and X86 CPU is important for network management. Our FPGA is auto-loading on attaching the radio to USB port and requires no programming by user for 99% of experiments. Only cases where very low latency of <1ms is required between Tx and Rx shall require code to be placed on FPGA. For all else SDR works in transparent mode from GnuRadio/OpenBTS/OpenLTE etc and X86 CPU handling most of the load while FPGA manages the clocks, buffer and RF ASIC.
Why choose amitec SDR-Lab ?
Simply because we already know what you want…..
We are compatible to MATLAB, LABVIEW & Linux – which no other system is
We provide PC with linux and Gnu-Radio/Octave pre-installed and tested to work with hardware – for your peace of mind
We eased the learning curve by offering 100 experiments pre loaded in PC so that you use it as library and improvise upon
We start with very basics because we understand the interdisciplinary nature of domain so that it is useful to a wider audience
There are no recurring cost of licences (like MATLAB, LABVIEW) to deal with so you save money over a period of time
The PC provided has Google Remote Desktop pre-installed for online support and remote update, trouble shooting so that you relax and enjoy
All the accessories needed are already supplied so there are no surprises and haggling later on
Two transceivers are supplied with two pcs for a group of 4 students so a radio link can be established on air
Wide frequency range of operation covers white spaces, telecom, ISM etc for most versatility
Transmit and Receive full duplex, half duplex, simplex, TDD, FDD or whatever you imagine
Complete guidance of courseware, curriculum, teaching methodology, lab manual as is designed with TRAINING in mind
Can we implement MIMO ?
Yes You would require 4 radios for a 2X2 system. So order 2 sets of SDR04.
Is it only Simulation or processing in Baseband or over the air RF link ?
This is real stuff. This is not a toy or a dummy baseband simulation. This is not an FPGA board connected to RF transceivers. This thing will actually talk to your mobile phone in the language it understands and which is what you want to learn too say 2G GSM or 4G LTE. So not only will it modulate/demodulate in baseband but also communicate to third party commercial equipment in desired protocol say Zigbee, Wifi etc in realtime!!!. So be a part of the telecom revolution yourself and not just sit on the fence and see it pass by you.
Can you suggest representative papers for various SDR applications
- 4G LTE Systems and Beyond
- Implementation of LTE-R Transceiver and the Performance with WINNER D2a Channel Model
- Low-Complexity Synchronization Method for Symbol and Frame Timing in LTE Systems
- LTE Femtocells Interference Scenario and Coexistence with the Brazilian Digital Broadcast System
- A Testbed for Evaluating LTE in High-Speed Trains
- LTE Signal Classification and Center Frequency Detection without Priori Information
- Dynamic spectrum access
- Wireless propagation measurements and modeling
- A wireless channel sounding system for rapid propagation measurements
- Spread spectrum channel sounder implementation with USRP platforms
- Channel sounding for the masses: Low complexity GNU 802.11b channel impulse response estimation
- Measurements of Multiple-Input Multiple-Output (MIMO) Performance under Army Operational Conditions
- See Through Walls with Wi-Fi!
- Wireless localization (e.g., to serve as a temporary infrastructure in disaster scenarios)
- Smart grid communications, and monitoring of smart metering infrastructure
- Cyber security for wireless communications and localization
- Device to device and multi-hop communications
- TV white space communications
- Multiple-Input Multiple-Output Communications (including massive MIMO applications)
- An experimental investigation of SIMO, MIMO, interference-alignment (IA) and coordinated multi-point (CoMP)
- Measurements of Multiple-Input Multiple-Output (MIMO) Performance under Army Operational Conditions
- Performance Study of MIMO-OFDM Platform in Narrow-band Sub-1 GHz Wireless LANs
- See Through Walls with Wi-Fi! (WiTrack: Through-Wall 3D Tracking Using Body Radio Reflections)
- Wireless radar
- Intelligent transportation system applications
- A USRP-based Testbed for OFDM-based Radar and Communication Systems
- Feasibility study of using FM radio for data transmission in a vehicular network
- Distributed autonomous multi-hop vehicle-to-vehicle communications over TV white space
- Flexible OFDM Waveform for PLC/RF In-Vehicle Communications
- Performance evaluation on using IEEE802.11p for indoor DSRC approach
- Experimental Evaluation of Routing Protocols for Vehicular Ad-hoc Networks Using GNU Radio and USRP
- In VIVO communications
- Implementation of GSM and LTE base stations
- The list is not possible to reproduce here so use Google or IEEE search……..
Government Thrust Areas for SDR ?
- Department of Electronics & Information Technology (DeitY)
- Convergence Communication Division (Deity)
- Cloud Communication
- Big data analytics for societal applications & disaster management
- Internet of things and CPS
- 4G and Beyond
- Broadband applications integrated with NOFN project
- Strategic Electronics
- Next Generation Communication & Convergence technologies (Software Defined Radio, Cognitive Radio including white spaces, Cooperative Communication, Cloud Computing/Communication over Cellular Network, Femto Cell, 60 GHz Wireless Network, Mobile Adhoc Network, Research in 4G/5G)
- Green Communication and Scavenging energy from ambient EM radiation.
- Wireless sensor networks
- Convergence of wired/wireless networks and fixed mobile convergence.
- Wireless Technology deployments for rural connectivity (LTE-A, Wi-Fi, Wi-Max, Amateur radio)
- Development of IP based products/services & Low Cost Broadband Internet access devices
- Digital addressable systems, Multilingual broadcast applications
- ICT applications in strategic sector with focus on safety, security and surveillance.
- Satcom products for use in distance education, telemedicine and other e-governance applications.
- Initiate studies in cutting edge technologies and development of road map.
The above list is for India. We are sure there is similar thrust by other countries as well…
How do we compare with other platforms ?
The complete SDR is implemented on a single 8 layer PCB for utmost reliability and repeatable performance. The RF front end is a single RF ASIC used for commercial BTS as against multiple chip solutions of competitors encased in EMI shield. Our radio is plucked from commercial 4G LTE EnodeB designed for 24/7 operation 365 days in all conditions for HYPER reliability. The transceiver is built on completely automated Robotic SMT pick and place machines in USA. Yes we do manufacture it in USA to take advantage of plethora of quality manufacturers and ecosystem there. Our’s is a full duplex transceiver as against cheap receivers only for 10$. We have 40,000,000 samples per second at 12bit precision on quadrature channels to give 40MHz of real-time transmit or receive bandwidth and enough to flood even USB 3.0 data bus at 5Gbps….phew. Check this link for overview of some other platforms: http://en.wikipedia.org/wiki/List_of_software-defined_radios
Please understand that amitec SDR-LAB is Hardware + Open source Software + Syllabus + Book + Teaching material + Training + Tech Support + Upgrade + Accessories in a complete package for academics and research. As against hardware only with proprietary software systems of others. Do consider this as you evaluate us against other systems.
So how do we implement the LAB ?
Experiments have over the air and simulation capabilities.
Students will work in groups of 2-4.
Each week students will implement a new block say modulation/demodulation or synchronization.
During the pre-lab student implements software, verifies it, answers pre-lab questions.
During the lab student demonstrates function to Teaching Assistant and answers in-lab questions.
After the lab student write a short lab report documenting what they learned.
Suggest LAB size and equipment ?
Course has 30-40 students enrolled each year.
LAB to have 10 SDR/PC for transmit and receive.
Students work in teams of 2-4.
Accommodate 20 students in the lab for 3 hours.
One TA services two lab sessions, grades homework, holds office hours.
How this Digital Wireless Communication Course works ?
The course is for undergraduates and graduates:
Pre-requisites: a course in digital signal processing and a course on probability.
Undergraduates take in 3rd or 4th year as a 4 credit course.
Graduate students take their 1st or 3rd semester.
Structure of the course:
3 hours of lecture per week, covers the theory of the course.
3 hours in the lab per week, demonstrate what has been learned.
Homework assignments test the theory.
Prelabs, labs, lab reports test what has been learned in the lab.
Yes and there are exams too……
Contents of this course done in LAB ?
- Digital communication overview
- Signals, stochastic processes
- Transforms, sampling theorem
- Frequency response, power spectrum, bandwidth
- Upconversion, downconversion, complex baseband
- Quadrature pulse amplitude modulation
- Optimal pulse shapes
- Maximum likelihood detection in AWGN
- Sample timing offset, sample timing algorithms
- Frequency selective channels, least squares channel estimation
- Frequency offset estimation and correction, frequency domain equalization
- Single carrier frequency domain equalization, OFDM, the cyclic prefix
- IEEE 802.11a, GSM standard
- Introduction to propagation, large-scale fading, link budgets, path-loss
- Small-scale fading, coherence time, coherence bandwidth
- Probability of error in fading channels
- Sources of diversity, Alalmouti space-time code, maximum ratio combining
- Introduction to MIMO communication, spatial multiplexing
- Introduction to MIMO-OFDM, highlights of the IEEE 802.11n standard
Materials developed for lecture ?
Textbook that describes the theory coauthored by Dr. Karun Rawat
Book is 400 pages, unpublished but available for use for free. Targeted for publishing by 2015.
Lecture Notes. LaTeX Form. 100’s of pages.
Materials developed for LAB ?
Laboratory manual SDR-LAB. Over 400 pages and over 100 experiments.
Include prelab to be completed prior to lab
Complete software framework
TA guide with solutions
Can you suggest other institutes where SDR is used for Lab?
It is a worldwide trend to use a re-configurable obsolescence free hardware along with open source software to teach advanced digital wireless communication and newer protocols. Check the syllabus of the following institutes University of Egypt, University of Stevens NY, NIT Warangal, University of Purdue, University of South Florida, Anna University, University of Colorado, Massachusetts Institute of Technology, University of Texas at Dallas, University of Texas at Austin, University of Arizona, San Jose State University, Texas A&M University, University of HongKong, Lunds University, Technical University Romania, Ohio State University, Universität Duisburg-Essen, University of Victoria, University of Colorado Springs, and many more are catching up. So why are you still waiting in the wings. Fly….
So how do you test SDR for quality & performance ?
Complete TRX is 100% tested on ATE for all parameters. Starting from receiver chain: the receiver is tested at all the frequencies over 1MHz interval for Gain, IQ Balance, DC Offset, Input IP3, Input IP2, Noise Figure. For 400-4000 MHz that makes over 3600X6 data points. This 21,600 data points are then repeated over different values of gain at 0.5dB interval over 50 dB dynamic range. So that make 216,000 tests of Rx chain. The transmitter chain is then tested for all frequencies over 1MHz interval from 400-4000MHz for Power, IQ Balance, DC Offset, Output IP3, Output IP2 and Nulling of mixer. The procedure is then repeated over all values of Tx gain. That makes 432,000 data points for RF ASIC. The testing the progresses to baseband. A very long story indeed. Check the following sample test report and testing paradigm.
So what are the recent improvements and additions ?
Frequency Down-converters to 40KHz and seamlessly integrated to software driver. Working on Up converters to 12GHz for Radar applications….
So what is the performance with USB 3.0 controllers?
USB 3.0 is a relatively new interface, and some USB 3.0 controllers do not perform reliably with devices like SDRs that stream data continuously. This is a list of controllers that we do not recommend:
- Any Renesas Technology Controller
- Any AS Media Controller
- NEC uPD720200
This is the primary reason we provide our own laptops with the SDR’s. Another being that Windows 8 does not allow BIOS modification for dual booting into Linux.
Typical USB 3.0 Performance
The table below show typical streaming performance when plugged into various USB 3.0 controllers. The rates are shown as a function of streaming configurations. In our test cases, the same streaming rate is used across all Tx/Rx channels. It is possible that performance will be impacted by other variables such as the operating system, processor, etc. The rates shown in the table below are not guaranteed on user computers.
USB 3.0 Performance (IQ Sample Transfer Rate in MS/s)
|“Intel Corporation 7 Series C210 Series Chipset Family USB xHCI Host Controller (rev 04)”||61.44||61.44||20|
|“NEC Corporation uPD720202”||36||44||39|
|“VIA Technologies VL80x xHCI USB 3.0 Controller (rev 03)”||60||61||29|
Notes: The numbers in front of TX and RX show how many channels are running in the benchmark. For example “1TX 1RX” means that there are one transmit stream and one receive stream running. All results are shown in MS/s.
Streaming Performance of Multi-Device Systems
It is possible to synchronize multiple SDR’s for MIMO operation. However, the performance may be negatively impacted if multiple devices are connected to the same USB controller on a PC. The benchmarks shown above do not account for multi-device configurations.