2,653 research outputs found
Analog Multiple Descriptions: A Zero-Delay Source-Channel Coding Approach
This paper extends the well-known source coding problem of multiple
descriptions, in its general and basic setting, to analog source-channel coding
scenarios. Encoding-decoding functions that optimally map between the (possibly
continuous valued) source and the channel spaces are numerically derived. The
main technical tool is a non-convex optimization method, namely, deterministic
annealing, which has recently been successfully used in other mapping
optimization problems. The obtained functions exhibit several interesting
structural properties, map multiple source intervals to the same interval in
the channel space, and consistently outperform the known competing mapping
techniques.Comment: Submitted to ICASSP 201
Energy-efficient Wireless Analog Sensing for Persistent Underwater Environmental Monitoring
The design of sensors or "things" as part of the new Internet of Underwater
Things (IoUTs) paradigm comes with multiple challenges including limited
battery capacity, not polluting the water body, and the ability to track
continuously phenomena with high temporal/spatial variability. We claim that
traditional digital sensors are incapable to meet these demands because of
their high power consumption, high complexity (cost), and the use of
non-biodegradable materials. To address the above challenges, we propose a
novel architecture consisting of a sensing substrate of dense analog
biodegradable sensors over which lies the traditional Wireless Sensor Network
(WSN). The substrate analog biodegradable sensors perform Shannon mapping (a
data-compression technique) using just a single Field Effect Transistor (FET)
without the need for power-hungry Analog-to-Digital Converters (ADCs) resulting
in much lower power consumption, complexity, and the ability to be powered
using only sustainable energy-harvesting techniques. A novel and efficient
decoding technique is also presented. Both encoding/decoding techniques have
been verified via Spice and MATLAB simulations accounting for underwater
acoustic channel variations.Comment: 5 pages, IEEE UComms 201
JSCC-Cast: A Joint Source Channel Coding Video Encoding and Transmission System with Limited Digital Metadata
[Abstract] This work considers the design and practical implementation of JSCC-Cast, a comprehensive analog video encoding and transmission system requiring a reduced amount of digital metadata. Suitable applications for JSCC-Cast are multicast transmissions over time-varying channels and Internet of Things wireless connectivity of end devices having severe constraints on their computational capabilities. The proposed system exhibits a similar image quality compared to existing analog and hybrid encoding alternatives such as Softcast. Its design is based on the use of linear transforms that exploit the spatial and temporal redundancy and the analog encoding of the transformed coefficients with different protection levels depending on their relevance. JSCC-Cast is compared to Softcast, which is considered the benchmark for analog and hybrid video coding, and with an all-digital H.265-based encoder. The results show that, depending on the scenario and considering image quality metrics such as the structural similarity index measure, the peak signal-to-noise ratio, and the perceived quality of the video, JSCC-Cast exhibits a performance close to that of Softcast but with less metadata and not requiring a feedback channel in order to track channel variations. Moreover, in some circumstances, the JSCC-Cast obtains a perceived quality for the frames comparable to those displayed by the digital one.This work has been funded by the Xunta de Galicia (by grant ED431C 2020/15 and grant ED431G 2019/01 to support the Centro de Investigación de Galicia “CITIC”), the Agencia Estatal de Investigación of Spain (by grants RED2018-102668-T and PID2019-104958RB-C42), and ERDF funds of the EU (FEDER Galicia 2014–2020 and AEI/FEDER Programs, UE)Xunta de Galicia; ED431C 2020/15Xunta de Galicia; ED431G 2019/0
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