Software defined radios (SDRs) provide software control over modulation techniques, bandwidth, security functions, and waveform requirements to support current and evolving standards across a broad frequency range. SDR is an enabling technology applicable across wireless industries as it provides efficient and inexpensive solutions to constraints in current and evolving systems. SDR architectural models define hardware platforms from different vendors running common software solutions and applications from different software vendors through a standard application programming interface.

1. Software Defined Radio Technology
The term software defined radios (SDRs) is used to describe radios that:
•provide software control of a variety of modulation techniques,
•wide-band or narrow-band operation,
•communications security functions, and
•waveform requirements of
•current and evolving standards
•over a broad frequency range.
SDR is an enabling technology
applicable across a wide range of areas
within the wireless industry that provides
efficient and comparatively inexpensive
solutions to several constraints posed in
current and evolving systems.
High-level hierarchical model of wireless communication and its main allocated functions
Input and output
Human interface, narrowband conversion
Service and network support
Multiplexing, setup and control, internetworking
Source coding and decoding
Audio, data, video and fax interfaces
Information security
Authentication, data integrity
Transmission security
Hopping, spreading
Modem and IF processing
Channel waveforms, predistortion, beamforming
RF access
Antenna, diversity, RF conversion
Channel sets
Simultaneity, multiband propagation
Information Transfer Thread
A
Information
Security
Fron End Processing
Information
Processing and I/O
Control
B
RF
Link
Processor
Modem
Information
Security
(TRANSEC)
Channel
set(s)
(INFOSEC)
C
Coding
Networking
I/O
Control
RF
specific
modules
Modem
specific
modules
TRSEC
specific
modules
ISEC
specific
modules
Coding
specific
modules
User I/O
specific
modules
Common
software
Common
software
Common
software
Common
software
Common
software
Common
software
Common
software
OS
OS
OS
OS
OS
OS
OS
Radio
infrastructure
Antenna
specific
modules
Radio
solution
SDR architectural and application model
Solution
(software)
Vendor #1
Firmware
Firmware
Firmware
Firmware
Firmware
Antenna
hardware
RF
hardware
Modem
hardware
TRANSEC
hardware
INFOSEC
hardware
Coding
hardware
User I/O
hardware
Hardware
platform
Firmware
Solution
(software)
Vendor #n
Common (Standard) Application Programming Interface
Platform
(hardware)
Vendor #1
Firmware
Solution
(software)
Vendor #2
Platform
(hardware)
Vendor #2
Platform
(hardware)
Vendor #n
One of the idea behind SDR technology is that different
applications from different vendors could run on different
platforms trough a standard API
Channel sets
RF
BB
real/com
dig/ana
RF
AUX
I/O
AUX
I
Antenna
AIR
I/O
AUX
I/O
I
RF
I
C
C
Bits
CypherT
FlowC
AUX
I/O
I
I/O
AUX
I
INFO
SEC
C
C
Bits
PlainT
FlowC
AUX
TRAN
SEC
Modem
C
C
Bits
CypherT
FlowC
C
C
Msg
Proc
and I/O
Remote
Control
Voice
Data
FlowC
C
Routing
C
Control
C: Control/Status
I: Information
BB: Baseband
FlowC: Flow Control
Source sets
SDR functional interface diagram and SDR implementation levels
Network
C
Common
User
Control
Software
Object interface
Power
Clock
0. Hardware radio
no provision is made for any changes of system
attributes
1. Software controlled radio
control functionality implemented in software, but
do not have the ability to change attributes
2. Software defined radio
provides a broad operational range wide-band or
narrow-band operation, communications security
functions
and meet the waveform performance requirements
of relevant legacy systems
3. Ideal software defined radio
eliminates analog amplification or heterodyne
mixing
prior to digital-analog conversion
For more information visit: http://www.sdrforum.org/tech_comm/definitions.html
www.sagax .
www.sagax.hu
Sagax, Ltd.
Sagax, Ltd.
Haller u. 11-13.
1096 Budapest, HUNGARY