3. 1.The antenna section, which receives (or transmits) information
encoded in radio waves.
2.The RF Front End section, which is responsible for
transmitting/receiving radio frequency signals from the antenna and
converting them to an Intermediate Frequency (IF).
3.The ADC/DAC section, which performs Analog-to-Digital/Digital-to-
Analog conversion.
4.The Digital Up Conversion (DUC) and Digital Down Conversion
(DDC) blocks,which essentially perform modulations of the signal on
the transmitting path and demodulation of the signal on the receiving
path.
5.The baseband section, which performs operations such as connection
setup,equalization, frequency hopping, coding/decoding, and
correlation, while also implementing the link layer protocol.
4. Software-Defined Radio (SDR) refers to the technology
wherein software modules running on a generic hardware platform
consisting of Field Programmable Gate Arrays (FPGAs), Digital
Signal Processors (DSPs), General Purpose Processors (GPPs),
programmable System on Chip (SoC) or other Application Specific
Programmable Processors are used to implement radio functions(also
referred to as physical layer processing) such as generation of
transmitted signal (modulation) at Transmitter(Tx), tuning/detection of
received radio signal (demodulation) at Receiver(Rx), filtering
(including bandwidth changes), and other functions such as frequency
selection and if required frequency hopping(wideband or narrowband
operation) and waveform requirements of current and evolving
standards over a broad frequency range.
Software Defined Radio (SDR)-Definition
7. • Technology makes feasible
• Multiplicity of Standards
• Multimedia services/standards and new devices
• Congestion management and spectrum management.
• Comment Commercial Market opportunities
• Flexible/reconfigurable(Easily upgradeability, customization, faster-time-to-market,
and adaptability)
– Reprogrammable units and infrastructure
• Software reusability
• Reduced obsolescence
– Multiband/multimode
• Ubiquitous connectivity
– Different standards(WiFi-IEEE 802.11,WiMAX-IEEE 802.16) can coexist
• Enhances/facilitates experimentation
• Potential for significant life-cycle cost reductions(Lower Maintenance cost)
• Uniform communication across commercial, civil, federal and military
organizations
• Brings analog and digital worlds together
– Full convergence of digital networks and radio science
– Networkable
Potential
Benefits/Significance/Features/Need/Advantages/
Merits of SDR
8. Explanation about potential benefits
• Technology makes feasible (also more necessary)
software radio makes it feasible to implement many of the complementary advances in wireless technology that
have occurred in recent years, including smart antennas, adaptive power management, or new modulation and
signal processing techniques. Therefore, just as technology makes it now feasible to adopt software radio, so
technology makes adopting software radio more necessary.
• Multiplicity of standards
The multiplicity of air interface technologies and standards that must co-exist today fuels demand for software
radio. For example, in the U.S., most cell phones roam by falling back on AMPS; although some newer models
support two digital standards (as well as AMPS). These "tri-mode" phones are more expensive to manufacture
than dual or single mode phones, and they still lack the capability to support the GSM technology that is
common in Europe and much of the rest of the world. Moreover, the proliferation of air interfaces for cellular
phones is not getting better as we move towards 3G services.
The proliferation of standards is due to many factors. First, globalization makes it desirable to have devices that
will operate in many countries, which may have quite different spectrum allocations, or even if the same
spectrum is used, may employ different protocols. Second, the rapid pace of innovation shortens the lifecycle of
each technology. This raises the premium for upgradeability and means that multiple generations are more likely
to overlap, co-existing at the same time. Third, the general movement towards increased reliance on market
control (via managed competition) instead of direct regulatory oversight may make it more likely that competing
service providers will fail to adopt common or interoperable standards.
9. • Multimedia services and new devices
The growth of diverse wireless services (voice, data, streaming content/video) and platforms (satellite, cellular, WLANs)
increases the diversity of potential wireless devices and services that may need to be integrated.
multimedia services increases the need for the ability to integrate multiple technologies and to support enhanced adaptability.
For example,Streaming media might be delivered via satellite while 2-way interactive communications may be supported via
cellular. Alternatively, 3G providers may seek to seamlessly integrate hotspot (WiFi) services into their offerings. Furthermore,
because different applications have very different quality of service requirements (bandwidth, latency, error tolerance), software
radios may facilitate supporting diverse QoS.
• Congestion management and spectrum management reform
As wireless services proliferate and use increases, congestion problems will arise. Software radio ameliorates the congestion
problem in three important ways.
1. software radio reduces the cost of expanding capacity on existing infrastructure. It is easier to add channels or move to a
higher capacity network protocol if this entails a software rather than a hardware upgrade.
2. software radios facilitate the implementation of quality of service (QoS) schemes and make it easier to engage in dynamic
capacity allocation.
3. software radio facilitates the adoption of distributed, adaptive, dynamic interference management solutions (e.g., two base
stations that need to communicate agree in real time to change their air interface protocol to accommodate an increase in local
interference).
The desire to facilitate more efficient spectrum usage, which would alleviate the congestion problem, is also encouraging
spectrum reform.
Explanation about potential benefits
10. • Comment Commercial market opportunities
The military has been interested in software radio for some time, and not surprisingly, some of the first
implementations have been in military applications.
1. they have a pressing need to be able to support multiple protocols to allow their radios to work
around the globe and to be capable of integrating signals from many RF sources (satellite, terrestrial,
etc.).
2.they have a strong need for security and need to be able to protect their ability to communicate in
hostile environments (e.g., in the face of jamming by enemy and congested battlefield conditions).
3.perhaps most important, the need for a strong defense makes the military much less price sensitive
than the typical consumer of commercial applications.
Explanation about potential benefits
11. • Uniform communication across commercial, civil, federal and
military organizations
• Low Power Wireless Applications
• Signals Intelligence
• Teaching Communications Systems
• Record and Playback
• Receive broadcast radio
• Industry, Research and Education.
Applications of SDR
20. I. ARCHITECTURE EVOLUTION(FOUNDATION)
• A. Functional Model of a Software Radio Node
• B. Classes of Software-Defined Radio (SDR)
II. TECHNOLOGY TRADEOFFS
• A. Antenna Tradeoffs
• B. RF and IF Processing Tradeoffs
• C. Interference Suppression
• D. RF MEMS(Micro Electro Mechanical Systems)
• E. Digital Architectures
• F. Smart Antenna Algorithms
III. ARCHITECTURE ANALYSIS
• A. Architecture: Definition and Goals
• B. Layering and Virtual Machines
• C. Object-Oriented Analysis
IV. RESEARCH ISSUES
1. Computational Stability
2. Hardware Reference Platforms
3. Direct Access to Hardware Facilities
4.Service Integration
21. Today Today Future
Evolution of Software Radio
ASIC’S
FPGA’S
DSP’S Programmable
ASIC’S
DSP’S
General purpose
processors
Today Future Future Time
Future
RF
digitalization
IF
digitalization
Analog +
Baseband
digitalization
SOFTWARE
RADIOS
TRADITIONAL
RADIOS
A/D Conversion closer to
Antenna
From dedicated to general
purpose hardware
Time
Software radio alters traditional radio designs in three distinct and complementary ways: it (1)
Moves Analog/Digital (A/D) conversion as close to the receiving antenna as possible:
(2)Substitutes software for hardware processing: and. (3) Facilitates a transition from
dedicated to general-purpose hardware. Each or these change, has, important implications for
the economics of wireless services.
22. First, moving the A/D conversion closer to the antenna makes, it possible to apply the
advances of digital computing and communication technology sooner in the radio. This is
beneficial directly because digital components arc less complex and lower cost than
analog components. Additionally. this. makes it easier to take advantage of advances in
digital signal processing. These include advanced technique encoding information and
separating signal from noise.
Second, substituting software for hardware increases flexibility. This flexibility makes
customization easier and helps deliver a degree of future-proofing. That is. replacing
software- especially if this can be done remotely is faster and lower-cost than replacing
hardware. New features and capabilities can be implemented when available
(upgradeability) or when desired (customizability). This can allow services to be changed
more rapidly. or equivalently, time to market is reduced. Additionally. the reliance on
software processing can eliminate redundant hardware chains. as found in dual-mode
phones.
Third, software radio facilitates the transition from dedicated to general-purpose
hardware. Initially, dedicated hardware embodied in Application Specific Integrated
Circuits (ASICs) may be replaced by Field Programmable Gate Arrays (FPGAs) and
Digital Signal Processors (DSPs) - which are even more commodity- like and flexible (see
Figure). Prospectively, there is a hope that general-purpose computing platforms (e.g. a
PC running on a commodity CPU) will be able to support software radios. At any given
point in time. a specialized chipset will typically achieve higher performance than a
general purpose processor. However, once Moore's Law drives the general-purpose
processor past a performance threshold such that it can perform the necessary radio
functions well enough, the advantages of general-purpose hardware come to the forefront.
24. • Channel Set therefore includes multiple RF bands. Personal
Communications System (PCS) base stations and mobile military
radios can also use fiber and cable, also included in the channel set.
• RF conversion comprise the RF/Channel Access function. RF
functions may include interference suppression.
• IF Processing may include filtering further frequency translation;
joint space-time equalization, integration of space/time diversity,
polarization or frequency diversity channels, digital beam forming
and smart antennas
• Modem performs modulator/demodulator RF channel.
• Bitstream processing includes Forward Error Control (FEC) and soft
decision decoding.
• Information Security (INFOSEC) is used for authentication reduces
fraud, and stream enciphering ensures privacy.
25. • Service & Network Support performs multiplexing ,setup and control, Data
services, Internetworking.
• Source Set may include Source Coding & Decoding of voice, data,
facsimile, video and multimedia. Some sources are physically remote from
the radio node.
e.g. connected via the Synchronous Digital Hierarchy (SDH), a Local Area
Network (LAN) or other network through Service & Network Support.
• Multiple software personalities is used to implement the each personality
combines RF band, channel set (e.g. control and traffic channels), air
interface waveform, protocol, and related functions.
• Joint control assures system stability, error recovery, and isochronous
streaming of voice and video.
Joint Control integrates fault modes, personalities, control interfaces to
all hardware and software and support functions on a limited resource of
ASICs,FPGAs,DSPs.
Joint Control may evolve towards autonomous selection of band, mode, and
data format.
• Evolution support is therefore necessary to define and manage the
waveform personalities, to download them and to assure that each new
personality is safe before being activated.
26. • B. Classes of Software-Defined Radio (SDR)
It is the function of digital access bandwidth(ADC/DAC) and
programmability.
This parameter-space quantitatively differentiates software radios ((V)-
(X)) from Programmable Digital Radios (PDRs) ((A)-(D)).
27. Commercial product of Standard Marine AB shown at point (A) used
baseband Analog to Digital Conversion (ADC), with DSP in the
TMS320C30 for high programmability.
cellular telephone handsets fall near (B).Application Specific Integrated
Circuits (ASICs) deliver processing capacity.
Digital cell site designs, (C),similarly, rely heavily on digital filter
ASICs for frequency translation and filtering, even though they access
the spectrum at IF.
SPEAKeasy II, (D), provides a programmable DSP, shifting this
implementation to the right.
The Virtual Radio (V), delivers a single channel radio using a general-
purpose processor.
Point (X) is the ideal software radio with digital RF and all functions
programmed on a RISC processor(general purpose).
28. II. TECHNOLOGY TRADEOFFS
• A. Antenna Tradeoffs
Antenna architecture determines the number and bandwidth of RF
channels.
The RF range extended from 2 MHz to 2 GHz, a ratio of 1000:1(3 decades).
Multiple parallel antenna/channels is used for 1G Advanced Mobile
Phone Systems(AMPS),2G GPS(Global Positioning System),2G digital
cellular Personal Communication Systems(PCS) and corporate wireless
LAN.
Two(Dual) parallel channels reducing parts count.
Unitary wideband channel such as broad RF range.
29. Four Software Radio Bands Span JTRS(Joint Tactical Radio
System)
SPEAKeasy bands were: 1) 2-30 MHz; 2)30-400 MHz; and 3) 0.4 to 2
GHz.
Bands 2 was implemented in SPEAKeasy I.
Bands 1 and 2 was implemented in SPEAKeasy II.
30. • B. RF and IF Processing Tradeoffs
The RF and IF conversion linearity and dynamic range must match the ADC
and Automatic Gain Control (AGC), and must support digital filtering and
signal enhancement algorithms.
Practical SDR
≡
31. • out-of-band signals are reduced by a BPF placed at the antenna
input, followed by a low-noise amplifier (LNA) and a mixer that
converts the signal to a first IF in the range of 100 to 200 MHz.
After the mixer, one or more stages of filters and amplifiers perform
channel filtering. The signal is then amplified and downconverted to
baseband for demodulation.
1.EXAMPLE(Not Necessary to Drawn but understanding purpose)
32. Spurious and LO leakage sometimes can mask subscriber/user signals.
The goal of this tradeoff is to balance the noise, spurious components,
intermodulation products, and artifacts (e.g. in interference-limited bands
below 400 MHz).
33. • C. Interference Suppression
Antenna separation, frequency separation, programmable analog notch
filters, and active cancellation(introduce a replica of the transmitted
signal)-suppress interference at the RF stage.
Without the roofing filter, the roof of the dynamic range is so high that weak
signals fall below the floor, resulting in dropped calls.
With the filter, the roof is low so that the dynamic range reaches the noise
floor.
Roofing filters need low insertion loss (< 0.5 dB), programmable center
frequency, and programmable bandwidth.
34. • D. RF MEMS
RF MEMS switches are an electromechanical alternative to PIN diode
switching circuits.
RF MEMS components reduce the RF/IF device size, enabling multiband
Personal Digital Assistants(PDAs) as an SDR delivery platform.
Substantially reducing size, weight, and power while improving
performance. MEMS switches and tunable capacitors operate up to 40
GHz.
36. It specifies functional grouping and interfaces.
In an N-element array, the channel isolation filters extract
channels for each of K users on each of N elements(K Users x N
Elements). Algorithms in the DSP pool form beams. They also extract
first-stage soft-decision parameters. Channels with low Carrier to
Interference Ratio (CIR) are thus identified. Their bulk-delayed signals
may be isolated for sequential interference cancellation, which also is
performed in the DSP pool. This pool provides the processors for
modulation and pre-distortion, including beamforming for
transmission. Switching functions employ the low-speed bus(low speed
digital interconnect-k users).
38. Matrix inversion for Smart Antennas substantially increases the
processing requirements, but yields improved performance.
Many techniques have been investigated to reduce the
computational burden of optimal algorithms, or to enhance the
cancellation capability of simpler algorithms.
39. III. ARCHITECTURE ANALYSIS
• A. Architecture: Definition and Goals
It supports
1. Plug-and-Play(Industry Wide component reuse)
2. the functional partitioning,
3. component interfaces, and
4. Related design rules ensure that hardware and software modules
from different suppliers work together when plugged into an
existing system.
40. • B. Layering and Virtual Machines
1. Protocol layering
E.g: wireless Internet services are supported by the Wireless Application
Protocol (WAP)
i.e interface layer between applications and the radio platform.
2. Virtual Machines
Java provides increased access to the underlying computational engine of
a handset.
The Java Virtual Machine (JVM) defines a general purpose computing
engine that hides the details of the computer’s native Instruction Set
Architecture (ISA).
41. • C. Object-Oriented Analysis
C, and C++ have been used to implement radio functions.
Radio objects use facilities of a CORBA-based Core Framework(CF) to
access radio facilities and computational resources.
The CORBA and its associated Interface Definition Language(IDL)
implement interfaces among S/W objects.
CORBA- Common Object Request Broker Architecture
42. IV. RESEARCH ISSUES
1. Computational Stability
2. Hardware Reference Platforms
With a variety of hardware implementations, it is difficult to determine
whether a specific hardware configuration will support a specific
software configuration.
3. Direct Access to Hardware Facilities
Tunneling and virtual machines may be integrated with CORBA and
radio applications objects.
4.Service Integration
The deployment of 3G, the proliferation of wireless LANs, and the
integration of GPS, video, thermal sensors, etc.
44. A SDR incorporated with the intelligence system that has the capability of
sensing the environment, optimizing the radio resources and learning the
system performance is called cognitive radio.
CR self adjusts(self aware)-Intelligent Radio(smart radio):
• CR programmed and configured-Dynamically.
• It have ability to Sense and Detect the conditions of their operating
environment and Dynamically reconfigure their own characteristics to best
match those conditions. If any interferes are detected in CR environment, then
CR provide automatically self adjusts(self aware) to provide best match
conditions.
45. Cognitive Radio network applications
1. Leased network: The primary network can provide a leased network by
allowing opportunistic access to its licensed spectrum with the agreement with a
third party without sacrificing the service quality of the primary user.
EX: Mobile Virtual Network Operator (MVNO)
2. Cognitive mesh network: xG networks have the ability to add temporary or
permanent spectrum to the infrastructure links used for relaying in case of high
traffic load.
3. Emergency network: emergency networks deal with the critical information,
reliable communication should be guaranteed with minimum latency.
(i.e) significant amount of radio spectrum for handling huge volume of traffic
including voice, video and data.
4. Military network: military networks have a strong need for security and
protection of the communication in hostile environment. To perform spectrum
handoff to find secure spectrum band for themselves
5. The Firework Disaster; Bandwidth Requirements; Spectrum
Organization; Propagation Conditions; White Space Assessment; System
Spectral Efficiency; Antijamming
