Advertisement
Product Releases
Advertisement

Making Wireless Ubiquitous

Wed, 02/11/2004 - 9:16am
Mike Chartier, Director of Regulatory Policy; Larry Swanson, Technology Marketing Manager, Corporate Technology Group, Intel Corporation

What if wireless capabilities could be added to every device by integrating the radio circuits and systems directly into each component? To make this wireless vision a reality, researchers are working in a wide variety of technology research areas. Just as CMOS (complementary metal-oxide semiconductor) process technology has provided cost and scale advantages in the evolution of microprocessors and chipsets, it is now being applied to radio technology. CMOS technology will make new capabilities possible like Reconfigurable Radio Architectures, smart antennas and ‘agile’ radios. At the same time, new industry standards and worldwide regulatory guidelines will be needed to support future anytime, anywhere connectivity.

CMOS Radio

Moore’s Law predicts that the number of transistors per unit area will double about every 2 years. This long-established trend and the improved device performance it generates are continuing to enable cost efficiency, greater volumes and interesting new applications in CMOS. Recently, it has become clear that the applicability of Moore’s Law is expanding to include new applications involving radio technology and networking.

Current research and development efforts include designing and manufacturing the necessary components of the radio’s Analog Front End and Digital Baseband / MAC (Media Access Control) on standard CMOS processes. As more digital processing is applied to the radio system, CMOS radios will follow the same decreasing cost and improving performance trajectories representative of the computing industry.

Reconfigurable Radio Architecture

As the application of Moore’s Law continues to produce the necessary transistors, and as analog RF (radio frequency) circuitry becomes feasible in CMOS technology, cost effective solutions are becoming possible to enable reconfigurable radio capabilities. Reconfigurable radio systems are radios that can change to different communication protocols as they move between different radio environments (i.e., 802.11b to 802.11a and then to W-CDMA). One possibility is a Reconfigurable Radio Architecture that will concurrently support multiple radio protocols over multiple frequency bands across multiple wireless networking environments.

Intel’s approach to a Reconfigurable Radio Architecture employs the use of computational elements optimized for specific compute functions, connected in a manner that implement the signal processing requirements of all wireless radio protocols. By employing an adequate number of specific computational elements, and programming different connection paths between these elements, multiple simultaneous protocols become possible.

At the same time, as analog RF CMOS circuitry becomes possible, the analog front end is expected to be produced more efficiently. This new efficiency will enable cost effective, multiple analog front-end solutions – and eventually reconfigurable solutions. The vision is that end users will have radio technology connecting them anytime, anywhere using single radio platforms integrated into any device they choose to use.

Smart Antenna Systems

As part of wireless system development, the industry is continually looking at ways to increase radio efficiency. One way is to use multiple “smart” antennas.

Potential implementations range from simple to complex. One approach would employ very simple technology where the more effective of two antennas is selected. A more sophisticated approach would use complex signal processing algorithms across an array of antennas. Smart antenna technology may be applied to improve signal reliability and increase data throughput while increasing both frequency and spatial utilization.

On the receiver side, a smart antenna system may be used to provide a multiplicative factor for increasing signal gain while also canceling the effects of multipath fading. On the transmit side, a smart antenna system may be used to concentrate the transmitted energy in a specific direction based on the location of the receiver.

Directing the energy in this manner not only improves performance but also helps reduce interference by isolating other radios not associated with the transfer and outside the directed transmission path. Smart antenna technology may also help to increase efficiency by simultaneously supporting an arbitrarily large number of clients using a single fixed set of antenna elements. This capability improves frequency reuse, resulting in increased spatial capacity.

The application of smart antenna technology will result in more efficient use of spectrum, which should help to increase range, network throughput and spatial capacity while reducing interference in an already crowded frequency spectrum.

Convergence and Regulatory Reform

In the future, it is expected that computing devices will communicate and communications devices will compute. Examples of radio applications significant to computing and communications convergence include:
—WWAN (wireless wide area networking), used for cellular telephone communications;
—WLAN (wireless local area networking), used for computer connectivity

More recently, WPAN (wireless personal area networking), finding many uses with smaller personal devices like cellular phones, PDAs (personal digital assistants), and even cameras. As devices become more intelligent, applications requiring radio connectivity are beginning to converge. Devices increasingly need to connect through more than one radio implementation. An example of this trend would be a cellular phone where connectivity is required for a cellular carrier (WWAN), for wireless headsets and/or email, calendar synchronization (WPAN) and for access to networking resources such as email and Internet services (WLAN). This example translates into at least three radios required for a single personal device, and possibly more as different protocols and radio bands become relevant in different geographical areas. As new capabilities like CMOS Radio, Reconfigurable Architecture and smart antenna technologies become possible, new “agile” radios are expected to become possible. An agile radio will provide the ability to select any supported radio protocol or associated frequency band using a single radio implementation. This approach to radio solutions should greatly accelerate convergence and simplify the end user experience.

Introducing an ‘agile’ radio concept, however, presents regulatory challenges as well as technical challenges. Intel is working with United States, European, Russian, Japanese and Chinese regulatory authorities to adapt regulatory guidelines for ‘agile’ radio technology.

Regulatory Update

Two types of agile radio technologies have impacted the regulatory environment in different ways. The first technology type is software defined radio (SDR). The SDR concept envisions a radio that can change its operating parameters after it has been certified. This presents a particular challenge to type approval and certification. The inaugural regulatory proceeding addressing this issue was the US FCC’s SDR Notice of Proposed Rule Making Docket 00-47. Intel was very active in this proceeding, and was pleased with Commission’s rules which came out September 13, 2001. Several key issues were the regulatory separation of radio software and applications, and freedom for manufacturers to define their own security mechanisms. Shortly after this FCC activity, the European Commission’s Telecommunication Conformity Assessment and Market Surveillance Committee (TCAM) began a special work group to study the impact of SDR on the EC’s governing regulations for radio’s the R&TTE directive. Intel has been involved in this process since its inception. The group developed a consultation document and is preparing a formal recommendation on the issue.

Likewise, the MPHPT of Japan commissioned TELEC to study the impact of SDR in 2000. TELEC has published its report and MPHPT has initiated a proceeding to developed Japanese SDR Regulations. On a global basis, Intel has been instrumental at the ITU-R. The ITU-R recommendation/report on SDR will assist in harmonizing global SDR regulations.

The second type of agile radio technology that impacts the regulatory community is the ability of the radio to sense its environment and adapt accordingly. Called “cognitive radio,” this concept involves innovative spectrum management techniques, termed overlays, that enable a radio to sense white space in the spectrum for opportunistic use.

The inaugural activity in this area was the ITU-R resolution enabling unlicensed devices to share spectrum with defense radar in the 5GHz band, by sensing the band and verifying its availability. Intel was key in negotiations with the US Government in determining the specific specifications to assure safe use, and also the international negotiations at the subsequent World Radio Conference that resulted in a WRC Resolution permitting such use on a Global basis. This resolution quickly codified into US and EC regulations in November 2003.

In addition, the FCC has initiated several proceedings such as a Notice of Inquiry exploring the opportunistic use of unused TV channels by unlicensed devices, and a Cognitive Radio and Second SDR Notice of Proposed Rulemaking that proposes among other things, using unlicensed devices with cognitive abilities to transmit at higher power. Cognitive abilities are also being investigated for licensed application such as allowing licensed spectrum users to lease and exchange spectrum on an opportunistic basis.

Summary

Using the low-cost and high-volume advantages of standard CMOS processes, wireless connectivity may soon be made ubiquitous – and ultimately, easier for the end-user. Innovative techniques such as reconfigurable radio architecture, smart antenna systems, and agile radios that adapt themselves to the conditions around them may soon become a reality. Intel and others in industry and government are working for more efficient use of the spectrum on a global basis, and to enable new spectrum management techniques and regulations that will foster innovative radio technologies.
Advertisement

Share this Story

X
You may login with either your assigned username or your e-mail address.
The password field is case sensitive.
Loading