1,348 research outputs found
Medium Access Control for Wireless Sensor Networks based on Impulse Radio Ultra Wideband
This paper describes a detailed performance evaluation of distributed Medium
Access Control (MAC) protocols for Wireless Sensor Networks based on Impulse
Radio Ultra Wideband (IR-UWB) Physical layer (PHY). Two main classes of Medium
Access Control protocol have been considered: Slotted and UnSlotted with
reliability. The reliability is based on Automatic Repeat ReQuest (ARQ). The
performance evaluation is performed using a complete Wireless Sensor Networks
(WSN) simulator built on the Global Mobile Information System Simulator
(GloMoSim). The optimal operating parameters are first discussed for IR-UWB in
terms of slot size, retransmission delay and the number of retransmission, then
a comparison between IR-UWB and other transmission techniques in terms of
reliability latency and power efficiency
Coded Slotted ALOHA: A Graph-Based Method for Uncoordinated Multiple Access
In this paper, a random access scheme is introduced which relies on the
combination of packet erasure correcting codes and successive interference
cancellation (SIC). The scheme is named coded slotted ALOHA. A bipartite graph
representation of the SIC process, resembling iterative decoding of generalized
low-density parity-check codes over the erasure channel, is exploited to
optimize the selection probabilities of the component erasure correcting codes
via density evolution analysis. The capacity (in packets per slot) of the
scheme is then analyzed in the context of the collision channel without
feedback. Moreover, a capacity bound is developed and component code
distributions tightly approaching the bound are derived.Comment: The final version to appear in IEEE Trans. Inf. Theory. 18 pages, 10
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Autonomous optimization of UWB link access
We present a novel approach for interference management in low data rate IR-UWB networks that enables concurrent transmissions at full power while allows each source to independently adapt its pulse rate (transmitted pulses per second) to mitigate multi-user interference. The work is motivated by the fact that the distributed adaptation of IR-UWB pulse rate has not been sufficiently addressed in the literature before. Existing approaches rely on the presence of a central authority or assume a definite receiver technique. Our approach enables users to share the communication medium in an efficient way compatible with individual QoS requirements and it is independent of any particular modulation scheme or receiver technique
Massive Access for Future Wireless Communication Systems
Multiple access technology played an important role in wireless communication
in the last decades: it increases the capacity of the channel and allows
different users to access the system simultaneously. However, the conventional
multiple access technology, as originally designed for current human-centric
wireless networks, is not scalable for future machine-centric wireless
networks.
Massive access (studied in the literature under such names as massive-device
multiple access, unsourced massive random access, massive connectivity, massive
machine-type communication, and many-access channels) exhibits a clean break
with current networks by potentially supporting millions of devices in each
cellular network. The tremendous growth in the number of connected devices
requires a fundamental rethinking of the conventional multiple access
technologies in favor of new schemes suited for massive random access. Among
the many new challenges arising in this setting, the most relevant are: the
fundamental limits of communication from a massive number of bursty devices
transmitting simultaneously with short packets, the design of low complexity
and energy-efficient massive access coding and communication schemes, efficient
methods for the detection of a relatively small number of active users among a
large number of potential user devices with sporadic transmission pattern, and
the integration of massive access with massive MIMO and other important
wireless communication technologies. This paper presents an overview of the
concept of massive access wireless communication and of the contemporary
research on this important topic.Comment: A short version has been accepted by IEEE Wireless Communication
Simulation Platform for Wireless Sensor Networks Based on Impulse Radio Ultra Wide Band
Impulse Radio Ultra Wide Band (IR-UWB) is a promising technology to address
Wireless Sensor Network (WSN) constraints. However, existing network simulation
tools do not provide a complete WSN simulation architecture, with the IR-UWB
specificities at the PHYsical (PHY) and the Medium Access Control (MAC) layers.
In this paper, we propose a WSN simulation architecture based on the IR-UWB
technique. At the PHY layer, we take into account the pulse collision by
dealing with the pulse propagation delay. We also modelled MAC protocols
specific to IRUWB, for WSN applications. To completely fit the WSN simulation
requirements, we propose a generic and reusable sensor and sensing channel
model. Most of the WSN application performances can be evaluated thanks to the
proposed simulation architecture. The proposed models are implemented on a
scalable and well known network simulator: Global Mobile Information System
Simulator (GloMoSim). However, they can be reused for all other packet based
simulation platforms
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