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An Introduction to the Software Defined Radio (SDR) Technology . Taewoon KIM. Future Wireless Communication. The increasing number of services and applications introduced various radio protocols. One device for many standards. The needs for SDR technology.
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An Introduction to the Software Defined Radio (SDR) Technology Taewoon KIM
Future Wireless Communication • The increasing number of services and applications introduced various radio protocols.
The needs for SDR technology • Advances in wireless communication technology produced various radio protocols. • Global roaming is highly required. • Poor use of the available bandwidth • Adding a new function into the existing infrastructure is very hard! • Adopting new standards takes much time. • H/W technology evolves fast.
Definition of SDR • Definition - Radio communication system where components that have typically been implemented in hardware (e.g. mixers, filters, amplifiers, modulators/demodulators, detectors. etc.) are instead implemented using software (Wikipedia) - Radio in which some or all of the physical layer functions are software defined (SDR forum) Multi-mode and multi-standards communication platform!!
What is SDR? • Software Defined Radio … • …is a radio communication system. • …can tune to any frequency band. • …can transmit or receive any modulation. • …does all these things by means of software. • The goal of SDR technology is to produce a radio that can receive and transmit virtually any existing or new form of radio protocol just by running new software. • It can reduce the cost of radios and system is easily reusable, reconfigurableand upgradeable without any change of existing hardware.
What is SDR? Software Defined Radio Hardware Radio
Conventional HW Radios • High Freq. in RF section • Medium Freq. in IF section • Low Freq. in Baseband section
Generic SDR Platform • RF section, contains the analog front-end that converts to and from the IF. • IF section contains ADC and DAC, and the digital down and up converters. • Baseband section that performs the bulk of the waveform and protocol processing.
Realization: GNU Radio • It’s a free software defined radio • A platform for signal processing on commodity hardware • Create a practical environment for experimentation & product delivery • Expand the “free software ethic ethic” into what were previously hardware intensive arenas • Sites • http://www.gnu.org/software/gnuradio • http://www.opencores.org/projects/pci
Why is SDR Emerging? • A single Hardware fits-to-all: multi-standard, multi-band and multi-functional systems • Easy software upgrade for add on functionalities • Customization of a single generic hardware for diverse needs • Higher levels of software reusability • Lower costs to meet new user demands • Less time to embody new standards
SDR Advantages • Complete Base band processing digital – Reconfigurable • Software upgrading of commercial radios – Future proof • Generic hardware can be used for a variety of applications – Inventory • Software prototyping faster and cheaper than hardware prototyping – Time to market • Libraries of software radio components are easily created and shared – Reuse • Digital processing of signals is ideal, unencumbered by the non-linearities that plague analog hardware-Reliability
Drawbacks • Large computational power is needed • Especially, IF section (modem, DDC/DUC) • Power consumption • Battery sizes • Complexity • Multimode devices • A/D performance • Accuracy, linearity, sampling rate, resolution • Higher initial costs
Advanced Techniques • Radios with intelligence • Smart antennas • Multi-user detection • Interference cancellation • Adaptive techniques • Over-the-air (OTA) provisioning and software download
Conclusion • SDR is useful for • Saving cost (not necessary replacing hardware) • Multi-band and multi-standard • Enhancing the system performance of functions • SDR has.. • Many opportunities and challenges