- Radio Signal Propogation and Processing
- Radio Modem Innovations
- Energy Improvement in Radio Processing
Utilize cognitive knowledge of the wireless channel to drastically reduce power consumption for memory dominated wireless systems.
The use of embedded memories in cellular and multimedia systems has grown rapidly in recent years fueled by advanced signal processing techniques. For example, at the physical layer, algorithms based on diversity approaches such as spatial diversity or multiplexing via multiple antenna processing, and time diversity via hybrid automatic repeat requests are improving performance dramatically, albeit at the cost of increased storage requirements and power consumption. To approach the power problem from a radically new perspective, it is important to realize that channel samples stored in memories have experienced statistical noise (i.e. a dynamically time varying wireless channel). Thus, to achieve a fixed level of quality at the output of the memory, it is reasonable to assume that the memory metrics (for example, supply voltage and reliability) can also be managed dynamically, depending on the quality of the data stored at a particular time instant. In this competition, we raise the following fundamental questions that challenge the status quo; a) Are memory power management schemes aware of the content they store? B) How would memory management policies diverge from current state of the art approaches, if that knowledge is available?
Our objective is to use new cognitive power management techniques for memory dominated mobile devices that exploit the variable nature of the wireless channel. The approach is based on the novel concept of Dynamic Margin Scaling which redefines architectural error tolerance of memory blocks based on the time varying tolerance of the application to hardware induced errors. Thus, the margin of acceptable performance can be dynamically managed by the needs of the application utilizing the hardware unit at that instant in time. Specifically, in the case of wireless systems, we exploit the slack in the received signal to noise ratio (SNR) to accordingly change the hardware noise at run time through aggressive voltage scaling. Depending on the scenario at hand, this approach leads to reducing power consumption by 20-40%, while maintaining the required quality of service (QoS). The proposed approach enables designers to abstract the concepts of power efficiency and error awareness for memory dominated devices early in the design cycle, with significant implications on the cost, performance and reliability attributes of the overall structure.
The team is uniquely qualified to carry this idea from theory to commercial success since we have done extensive work analyzing the memory requirements and performance of numerous wireless and multimedia system blocks such as video encoding/decoding, forward error correction (FEC), equalization…etc. In future work, we plan to leverage our current framework towards building a prototype system that incorporates model free learning algorithms that capture the statistical nature of the wireless channel and link that to different controls at the application, architecture and physical layers.
Today, mobile and power conscious devices are not only the most ubiquitous of consumer products, but are also increasingly adopted in industrial and commercial markets opening up tremendous market opportunities. For example, low power wireless is increasingly used in mission-critical tasks spanning healthcare to emergency response, scientific exploration, military command and control and utilities such as Smart Grid etc. The proposed idea will enable new paradigms for the rapid design, development and deployment of such inexpensive and energy-efficient devices and has the potential to have a transformative impact on current design practices.
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The team leader Professor Eltawil has been with the University of California, Irvine since January '05. Between '00 and '03, he was the director of VLSI Engineering at a semiconductor company (Innovics Wireless) where he led the team to develop the first patented diversity enabled mobile, system on a chip (SoC), for WCDMA Rel 99. From '03-'05 he was at Silvus Communications (Los Angeles, CA), where he helped establish the company as a leader in multiple antenna radios. From ‘05 to ‘09 he worked with the founding team of Newport Media (Lake Forest, CA) as an expert consultant. Since ‘06, he has been a member of the Association of Public Safety Communications Officials (APCO) working to advance critical first responder networks. At the University of California, Irvine, he is the founder and director of the Wireless Systems and Circuits Laboratory. This mix of industry and academia gives us a unique perspective on what is required to make the team succeed and have a significant impact.