Andres Kwasinski

3D video communications: Challenges and opportunities

This paper surveys major techniques in 3D communications area, which covers the whole pipeline of the 3D video communication framework, including 3D content creation, data representation, compression, delivery, decompression, post-processing, and 3D scene rendering stages. Both the current state-of-the-art, stereo 3D, and future trend, free-viewpoint 3D, are demonstrated in details. On the other hand, the paper highlights a few features in the emerging 4G wireless systems that are critical for 3D communications system design. At the end, the topics with potential but challenges, for example 3D over 4G networks, distributed 3D video coding, 3D multi-user communication, scalability and universal 3D access, are discussed and pointed out to audiences for further investigation. Copyright

CDMA Enabled Wireless Network-on-Chip

Multihop communication links in conventional Networks-on-Chips (NoCs) results in lower rates of data transfer and higher energy dissipation. Long-range millimeter-wave wireless interconnects were envisioned to alleviate this problem. However, the available bandwidth of the wireless channels is limited and hence an efficient media access control (MAC) scheme is required to enhance the utilization of the available bandwidth. In this article we show that with multiple simultaneous access of the shared wireless medium using a Code Division Multiple Access (CDMA) scheme the peak performance can be improved significantly while lowering energy dissipation in data transfer compared to the conventional wireline counterparts as well as state-of-the-art Wireless NoCs using similar technologies. We present a thorough analysis of the reliability in data transfer using the CDMA based wireless links and show that a reliability-aware architecture design with CDMA based wireless links can lower the energy dissipation in NoC fabrics without compromising the achievable robustness.

Source-Channel-Cooperation Tradeoffs for Adaptive Coded Communications [Transactions Papers]

Transmit power limitations and quality-impairing channels present key challenges to wireless communications. A possible solution to these problems is the application of user-cooperation techniques so as to improve link quality. This paper studies the tradeoffs involved in combining user cooperation with practical source and channel coding in systems featuring rate-adaptive source and channel coding of conversational traffic. Performance is measured through the D-SNR curve, which measures the relation between end-to-end distortion and channel signal-to-noise ratio (SNR). The D-SNR curve is accurately characterized as a linear function in log-log scales. Also, it is shown that the tradeoffs involved in combining amplify-and-forward or decode-and-forward cooperation with source and channel coding translates into cooperative schemes showing a decrease in distortion at approximately half the rate as non-cooperative schemes but with larger coding gain. Because of this, the studied non-cooperative schemes show better performance only at high SNR. In addition, the D-SNR characterization is used to compare amplify-and-forward and decode-and-forward cooperation for channel codes of different strength and to study the effects of source codec efficiency, where it is shown that diversity gain is reduced proportionally to the source codec loss of efficiency.

Architecture for green mobile network powered from renewable energy in microgrid configuration

This paper introduces an architecture for powering green mobile networks with a majority of renewable sources. The architecture makes use of wind turbines and photovoltaic panels as sources of electric power for cellular base stations. The electric power generators are located within the cellular network in a microgrid configuration. The microgrid configuration allows for a more efficient management of electric resources and a more resilient cellular system architecture. In addition, the microgid configuration allows for a management of the cellular network resources more tightly coupled with the electric power grid status and viceversa. The presented results will show that it is possible to power a cellular network from renewable source for us much as 90 % of the time. This work also discussed traffic shaping and management techniques so as to power off one cell to increase the use of renewable energy sources even when the traffic is not at a low level. The technique is effective in maintaining within reasonable values the reduction of voice traffic quality and the increasing in data queuing delay.

NoC architectures with adaptive Code Division Multiple Access based wireless links

Multi-hop data transfer in conventional Networks-on-Chips (NoCs) results in lower rates of data transfer and higher energy dissipation. Long-range millimeter-wave wireless interconnects were envisioned to alleviate this problem. However, as the bandwidth of the wireless channels is limited an efficient media access control (MAC) scheme is required to enhance the utilization of the available bandwidth. In this paper we show that with multiple simultaneous access of the shared wireless medium using a traffic-adaptive Code Division Multiple Access (CDMA) scheme the peak performance can be improved significantly while lowering energy dissipation in data transfer compared to the conventional wireline counterparts.

Highly accurate non-intrusive speech forensics for codec identifications from observed decoded signals

The ability to detect a particular speech codec from only the decoded audio has several useful forensic and system performance improvement applications. This paper presents a novel scheme for non-intrusive identification of speech codecs. The identification approach is based upon comparing a profile of a set of noise spectra and a time-domain histogram from the decoded speech to those from the candidate codecs. The presented results show a very high accuracy in identifying speech contemporary codecs from a diverse set of types and encoding rates. The presented codec identification scheme has a very low misidentification rate, including in the high coding rate regime where it improves on previous works by achieving perfect identification. This performance is achieved while reducing the duration of the analysis window of speech from 2 minutes to only 4 seconds.

A Survey on Applications of Model-Free Strategy Learning in Cognitive Wireless Networks

The framework of cognitive wireless networks is expected to endow the wireless devices with the cognition-intelligence ability with which they can efficiently learn and respond to the dynamic wireless environment. In many practical scenarios, the complexity of network dynamics makes it difficult to determine the network evolution model in advance. Thus, the wireless decision-making entities may face a black-box network control problem and the model-based network management mechanisms will be no longer applicable. In contrast, model-free learning enables the decision-making entities to adapt their behaviors based on the reinforcement from their interaction with the environment and (implicitly) build their understanding of the system from scratch through trial-and-error. Such characteristics are highly in accordance with the requirement of cognition-based intelligence for devices in cognitive wireless networks. Therefore, model-free learning has been considered as one key implementation approach to adaptive, self-organized network control in cognitive wireless networks. In this paper, we provide a comprehensive survey on the applications of the state-of-the-art model-free learning mechanisms in cognitive wireless networks. According to the system models on which those applications are based, a systematic overview of the learning algorithms in the domains of single-agent system, multiagent systems, and multiplayer games is provided. The applications of model-free learning to various problems in cognitive wireless networks are discussed with the focus on how the learning mechanisms help to provide the solutions to these problems and improve the network performance over the model-based, non-adaptive methods. Finally, a broad spectrum of challenges and open issues is discussed to offer a guideline for the future research directions.

Cooperative multimedia communications: joint source coding and collaboration

Cooperative diversity exploits the broadcast nature of wireless channels by allowing users to relay information for each other so as to create multiple signal paths. This paper analyzes what is the best strategy from the viewpoint of a resource allocation protocol, to match source coding with cooperation diversity for conversational multimedia communications by studying the distortion performance for different schemes. The results show that the best performance is obtained when all layers of a layered-coded source are sent with user cooperation (using decode-and-forward in most cases) if the source-destination channel is bad, and with no user cooperation, if the source-destination channel is good. The results also show that the gains from cooperative diversity outweigh the loss due to the sacrifice in overall bandwidth and that cooperation performance is sensitive to the proportion of communication capacity allocated for cooperation.

Operational aspects and power architecture design for a microgrid to increase the use of renewable energy in wireless communication networks

Discusses the design of a power and control architecture for wireless communication networks that enables an increased use of renewable energy sources than in the conventional present approach. In the proposed approach a group of cell sites forms a dc microgrid in which their power consumption is coordinated with the power generated from renewable sources in order to manage local energy resources effectively. That is, load management is coordinated with power generation and use of local energy storage. In addition to environmental benefits, this proposed microgrid enhances power supply availability in cell sites and, thus, may improve wireless networks performance during natural disasters and other extreme events.

Signal Processing in the Electrification of Vehicular Transportation: Techniques for Electric and Plug-In Hybrid Electric Vehicles on the Smart Grid

This tutorial aims at explaining how signal processing techniques can be used to manage EVs connected to the smart grid. It also introduces the main issues and challenges related with the operation of EVs in the presence of a smart grid infrastructure and how signal processing techniques can be applied in this context.