Videos
Measurement Campaigns for Spectrum Occupancy
Measurement Campaigns for Spectrum Occupancy
Sumit Roy
01:02:01 · 2 July 2014

The evolution of cognitive (secondary) networks to enable more efficient spectrum usage will rely on fast and accurate spectrum sensing/mapping, supported by a suitable architecture for data integration and model building. In the first part of the talk, fundamental aspects of the wide-area RF mapping problem as a grand challenge will be highlighted; and some recent work at UW that clarifies sub-system level trade-offs (between scan latency and channel status estimation accuracy, for example) will be described. Next, the evolution of a hybrid architecture - decentralized client-side sensing assisted database updating - is explored. Within this, model-based answers to fundamental questions such as 'how much white space capacity is available' as a function of location for U.S. TV bands are developed. The talk will conclude with a description of current efforts for spectrum sharing (co-existence) just underway in the 3 GHz band (broadly) between different primaries (largely government operated communications such as military and non-military radars) and commercial networks (802.11 and 4G LTE).

White Space Networking and Spectrum Sharing - Part 2
White Space Networking and Spectrum Sharing - Part 2
Sumit Roy
01:16:00 · 2 July 2014

The evolution of cognitive (secondary) networks to enable more efficient spectrum usage will rely on fast and accurate spectrum sensing/mapping, supported by a suitable architecture for data integration and model building. In the first part of the talk, fundamental aspects of the wide-area RF mapping problem as a grand challenge will be highlighted; and some recent work at UW that clarifies sub-system level trade-offs (between scan latency and channel status estimation accuracy, for example) will be described. Next, the evolution of a hybrid architecture - decentralized client-side sensing assisted database updating - is explored. Within this, model-based answers to fundamental questions such as 'how much white space capacity is available' as a function of location for U.S. TV bands are developed. The talk will conclude with a description of current efforts for spectrum sharing (co-existence) just underway in the 3 GHz band (broadly) between different primaries (largely government operated communications such as military and non-military radars) and commercial networks (802.11 and 4G LTE).

Peter Lee Address to Summer School 2014 Attendees
Peter Lee Address to Summer School 2014 Attendees
Peter Lee
00:44:10 · 1 July 2014

Software defined radios are a powerful tool for experimenting with wireless PHY and MAC layers. At the same time, they are a challenging programming environment, given tight timing constraints imposed. A student who wants to venture in this area of research needs to master computer architecture and hardware, as well as numerous algorithms for signal processing and communication. In this lecture we will talk about Ziria, a programming language and a compiler that we have recently developed to simplify this task. Ziria is a high-level language, specialized for PHY design, that delegates most of the burdensome hardware optimization to the compiler and allows us to keep the code design clean and simple. We will walk through various building blocks of Wifi PHY design and show how to implement them in Ziria. At the end of the talk you should be able to understand the signal processing foundations of WiFi as well as to quickly implement and deploy your own PHY using Ziria. Ziria compiler is open sourced so you will be able to download it and play with the code yourselves. It currently supports Sora SDR platform but could be easily adapted to other similar platforms.

Ziria: Wireless Programming for Hardware Dummies - Part 4
Ziria: Wireless Programming for Hardware Dummies - Part 4
Bozidar Radunovic
01:01:39 · 1 July 2014

Software defined radios are a powerful tool for experimenting with wireless PHY and MAC layers. At the same time, they are a challenging programming environment, given tight timing constraints imposed. A student who wants to venture in this area of research needs to master computer architecture and hardware, as well as numerous algorithms for signal processing and communication. In this lecture we will talk about Ziria, a programming language and a compiler that we have recently developed to simplify this task. Ziria is a high-level language, specialized for PHY design, that delegates most of the burdensome hardware optimization to the compiler and allows us to keep the code design clean and simple. We will walk through various building blocks of Wifi PHY design and show how to implement them in Ziria. At the end of the talk you should be able to understand the signal processing foundations of WiFi as well as to quickly implement and deploy your own PHY using Ziria. Ziria compiler is open sourced so you will be able to download it and play with the code yourselves. It currently supports Sora SDR platform but could be easily adapted to other similar platforms.

Ziria: Wireless Programming for Hardware Dummies - Part 3
Ziria: Wireless Programming for Hardware Dummies - Part 3
Bozidar Radunovic
00:58:21 · 1 July 2014

Software defined radios are a powerful tool for experimenting with wireless PHY and MAC layers. At the same time, they are a challenging programming environment, given tight timing constraints imposed. A student who wants to venture in this area of research needs to master computer architecture and hardware, as well as numerous algorithms for signal processing and communication. In this lecture we will talk about Ziria, a programming language and a compiler that we have recently developed to simplify this task. Ziria is a high-level language, specialized for PHY design, that delegates most of the burdensome hardware optimization to the compiler and allows us to keep the code design clean and simple. We will walk through various building blocks of Wifi PHY design and show how to implement them in Ziria. At the end of the talk you should be able to understand the signal processing foundations of WiFi as well as to quickly implement and deploy your own PHY using Ziria. Ziria compiler is open sourced so you will be able to download it and play with the code yourselves. It currently supports Sora SDR platform but could be easily adapted to other similar platforms.

White Space Networking and Spectrum Sharing
White Space Networking and Spectrum Sharing
Sumit Roy
02:07:18 · 30 June 2014

The evolution of cognitive (secondary) networks to enable more efficient spectrum usage will rely on fast and accurate spectrum sensing/mapping, supported by a suitable architecture for data integration and model building. In the first part of the talk, fundamental aspects of the wide-area RF mapping problem as a grand challenge will be highlighted; and some recent work at UW that clarifies sub-system level trade-offs (between scan latency and channel status estimation accuracy, for example) will be described. Next, the evolution of a hybrid architecture - decentralized client-side sensing assisted database updating - is explored. Within this, model-based answers to fundamental questions such as 'how much white space capacity is available' as a function of location for U.S. TV bands are developed. The talk will conclude with a description of current efforts for spectrum sharing (co-existence) just underway in the 3 GHz band (broadly) between different primaries (largely government operated communications such as military and non-military radars) and commercial networks (802.11 and 4G LTE).

Ziria: Wireless Programming for Hardware Dummies - Part 2
Ziria: Wireless Programming for Hardware Dummies - Part 2
Bozidar Radunovic
00:55:52 · 30 June 2014

Software defined radios are a powerful tool for experimenting with wireless PHY and MAC layers. At the same time, they are a challenging programming environment, given tight timing constraints imposed. A student who wants to venture in this area of research needs to master computer architecture and hardware, as well as numerous algorithms for signal processing and communication. In this lecture we will talk about Ziria, a programming language and a compiler that we have recently developed to simplify this task. Ziria is a high-level language, specialized for PHY design, that delegates most of the burdensome hardware optimization to the compiler and allows us to keep the code design clean and simple. We will walk through various building blocks of Wifi PHY design and show how to implement them in Ziria. At the end of the talk you should be able to understand the signal processing foundations of WiFi as well as to quickly implement and deploy your own PHY using Ziria. Ziria compiler is open sourced so you will be able to download it and play with the code yourselves. It currently supports Sora SDR platform but could be easily adapted to other similar platforms.

Ziria: Wireless Programming for Hardware Dummies - Part 1
Ziria: Wireless Programming for Hardware Dummies - Part 1
Bozidar Radunovic
01:06:21 · 30 June 2014

Software defined radios are a powerful tool for experimenting with wireless PHY and MAC layers. At the same time, they are a challenging programming environment, given tight timing constraints imposed. A student who wants to venture in this area of research needs to master computer architecture and hardware, as well as numerous algorithms for signal processing and communication. In this lecture we will talk about Ziria, a programming language and a compiler that we have recently developed to simplify this task. Ziria is a high-level language, specialized for PHY design, that delegates most of the burdensome hardware optimization to the compiler and allows us to keep the code design clean and simple. We will walk through various building blocks of Wifi PHY design and show how to implement them in Ziria. At the end of the talk you should be able to understand the signal processing foundations of WiFi as well as to quickly implement and deploy your own PHY using Ziria. Ziria compiler is open sourced so you will be able to download it and play with the code yourselves. It currently supports Sora SDR platform but could be easily adapted to other similar platforms.

Fixed Point Analysis of Single Cell IEEE 802.11(e) WLANs - Part 2
Fixed Point Analysis of Single Cell IEEE 802.11(e) WLANs - Part 2
Venkatesh Ramaiyan
01:06:15 · 29 June 2014

We consider the vector fixed point equations arising out of a saturation throughput analysis of a single cell IEEE 802.11e (EDCA) WLAN. We study balanced and unbalanced solutions of the fixed point equations arising in homogeneous (i.e., one with the same backoff parameters) and nonhomogeneous networks. By a balanced fixed point, we mean one where all coordinates are equal. We are concerned, in particular, with 1) whether the fixed point is balanced within a class of users, and 2) whether the fixed point is unique. For IEEE 802.11 type WLANs, we provide a condition, based on the backoff parameters, for the vector fixed point solution to be balanced within a class, and also a condition for uniqueness of the solution. We then provide an extension of our general fixed point analysis to capture AIFS based differentiation and multiple virtual queues (supported in IEEE 802.11e EDCA); again a condition for uniqueness is established and simulations validate the analysis. The fixed point solutions are used to obtain insights into the throughput differentiation provided by different initial back-offs, persistence factors, AIFS and multiple virtual queues, for finite number of nodes, and for differentiation parameter values similar to those in the standard. Our simulations show that when multiple unbalanced fixed points exist then the time behavior of the system demonstrates severe short term unfairness (or multistability). Implications for the use of the fixed point formulation for performance analysis will be discussed.

Fixed Point Analysis of Single Cell IEEE 802.11(e) WLANs - Part 1
Fixed Point Analysis of Single Cell IEEE 802.11(e) WLANs - Part 1
Venkatesh Ramaiyan
01:01:23 · 29 June 2014

We consider the vector fixed point equations arising out of a saturation throughput analysis of a single cell IEEE 802.11e (EDCA) WLAN. We study balanced and unbalanced solutions of the fixed point equations arising in homogeneous (i.e., one with the same backoff parameters) and nonhomogeneous networks. By a balanced fixed point, we mean one where all coordinates are equal. We are concerned, in particular, with 1) whether the fixed point is balanced within a class of users, and 2) whether the fixed point is unique. For IEEE 802.11 type WLANs, we provide a condition, based on the backoff parameters, for the vector fixed point solution to be balanced within a class, and also a condition for uniqueness of the solution. We then provide an extension of our general fixed point analysis to capture AIFS based differentiation and multiple virtual queues (supported in IEEE 802.11e EDCA); again a condition for uniqueness is established and simulations validate the analysis. The fixed point solutions are used to obtain insights into the throughput differentiation provided by different initial back-offs, persistence factors, AIFS and multiple virtual queues, for finite number of nodes, and for differentiation parameter values similar to those in the standard. Our simulations show that when multiple unbalanced fixed points exist then the time behavior of the system demonstrates severe short term unfairness (or multistability). Implications for the use of the fixed point formulation for performance analysis will be discussed.

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