Thursday, April 15, 2010

Dynamic Spectrum Access Regulatory Models

The current model of RF Frequency management is to assign frequency bands to groups and applications. This mitigates the problem of interference and controls to some extent the usage of the RF spectrum. In many of the allocated bands, the usage of the alloted spectrum runs from 0.03 to 3%. As spectrum becomes scarce due to a growing use of existing applications and new applications requiring additional bandwidth come on the market, the spectrum access model is coming under scrutiny. A newer Dynamic Spectrum Access Regulatory model is coming into focus. In this model, the spectrum is not allocated but rather users are allowed to make use of a frequency band if they can do so without interfering with other users in that band.

The key conference in this area is the IEEE Dyspan (Dynamic Spectrum Access Network ). The purpose of the group is

" to expand collective understanding of complex next-generation wireless systems focused on using RF spectrum more efficiently and dynamically. This includes advancing both cutting edge technical and multidisciplinary research as well as practical experience related to building a healthy industry/regulatory ecosystem for the commercialization of smart radio system technologies.

As networks and devices increasingly gain intelligence and "cognitive" capabilities, and as regulators around the world seek to enhance spectrum utilization through exploiting areas such as "white spaces", dynamic decentralized access is becoming one of the most important, but most complex topics in wireless communications development. IEEE DySPAN 2010 will continue investigation of decentralized spectrum access and focus on approaches for highly scalable dynamic optimization of wireless spectrum use. "

There are several initiatives to further the Dynamic Spectrum Access effort. One is the Potential Alliance for World-wide Dynamic Spectrum Access by the New America Foundation. The group seeks to foster better working relationship between military, consumer, and public-safety groups.

Best regards,

Hall T.

Friday, April 09, 2010

What will the "IBM PC" of SDR Look Like?

The IBM PC revolutionized the personal computer industry by bringing standards to a low-cost personal computer platform. It became the dominant design drawing from several industry-proven technical solutions and covering many market segments. It held the right tradeoff balance between technical performance and market requirements. Up until the entry of the IBM PC the market was flush with competing standards and methodologies. An "IBM PC" solution will eventually come to the SDR world. Software defined radio will see much greater success if it can generate a dominant design solution rather than a splintered approach.

So what are the key elements that need to be synthesized into a dominant design? In this paper the authors argue that it will bring portability of waveforms, maintainability, and allow specialization of waveforms.

Another key factor will be size. It will be greatly reduced from what we see today. Just as the IBM PC took computing from the mainframe/mincomputer world down to the desktop so the next generation of SDR will go down in size. Here's one example using Gumstix.

Finally, the cost must be low and the tools widely available. Defacto standards available at low cost will drive SDR applications into new areas and create a richer set of tools for more sophisticated applications.

Best regards,

Hall T.

Friday, April 02, 2010

SDR for Public Safety Applications--Interoperability

Public Safety (Fire, police, first responders, etc) are now looking at Software Defined Radio to generate interoperability among the first responders who have incompatible radios between groups. By bridging the gap through multi-band and multi-service radios. In addition to interoperability, cognitive radio techniques could also help first responder radios adapt to their environment. Consider a Katrina-situation in which the local telecom infrastructure is wiped out requiring radios to adapt to a new infrastructure. To address the issue the National Public Safety Telecomunications Council was formed to study and advise on the issues.

The key challenges in public safety applications are spectrum usage and multi-band bridging. Public radios do not use the spectrum efficiently and consequently runs out. Also first responder radios operate on different bands which must be bridged as described in this market research executive summary report.

Best regards,

Hall T.