750 research outputs found
Goodbye, ALOHA!
©2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The vision of the Internet of Things (IoT) to interconnect and Internet-connect everyday people, objects, and machines poses new challenges in the design of wireless communication networks. The design of medium access control (MAC) protocols has been traditionally an intense area of research due to their high impact on the overall performance of wireless communications. The majority of research activities in this field deal with different variations of protocols somehow based on ALOHA, either with or without listen before talk, i.e., carrier sensing multiple access. These protocols operate well under low traffic loads and low number of simultaneous devices. However, they suffer from congestion as the traffic load and the number of devices increase. For this reason, unless revisited, the MAC layer can become a bottleneck for the success of the IoT. In this paper, we provide an overview of the existing MAC solutions for the IoT, describing current limitations and envisioned challenges for the near future. Motivated by those, we identify a family of simple algorithms based on distributed queueing (DQ), which can operate for an infinite number of devices generating any traffic load and pattern. A description of the DQ mechanism is provided and most relevant existing studies of DQ applied in different scenarios are described in this paper. In addition, we provide a novel performance evaluation of DQ when applied for the IoT. Finally, a description of the very first demo of DQ for its use in the IoT is also included in this paper.Peer ReviewedPostprint (author's final draft
From 5G to 6G: Has the Time for Modern Random Access Come?
This short paper proposes the use of modern random access for IoT
applications in 6G. A short overview of recent advances in uncoordinated medium
access is provided, highlighting the gains that can be achieved by leveraging
smart protocol design intertwined with advanced signal processing techniques at
the receiver. The authors' vision on the benefits such schemes can yield for
beyond-5G systems is presented, with the aim to trigger further discussion.Comment: 2 pages, 1 figure, presented at 6G Summit, Levi, Finland, 201
User Activity Detection in Massive Random Access: Compressed Sensing vs. Coded Slotted ALOHA
Machine-type communication services in mobile cel- lular systems are
currently evolving with an aim to efficiently address a massive-scale user
access to the system. One of the key problems in this respect is to efficiently
identify active users in order to allocate them resources for the subsequent
transmissions. In this paper, we examine two recently suggested approaches for
user activity detection: compressed-sensing (CS) and coded slotted ALOHA (CSA),
and provide their comparison in terms of performance vs resource utilization.
Our preliminary results show that CS-based approach is able to provide the
target user activity detection performance with less overall system resource
utilization. However, this comes at a price of lower energy- efficiency per
user, as compared to CSA-based approach.Comment: Accepted for presentation at IEEE SPAWC 201
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Approaching Fair Collision-Free Channel Access with Slotted ALOHA Using Collaborative Policy-Based Reinforcement Learning
Frameless ALOHA with Reliability-Latency Guarantees
One of the novelties brought by 5G is that wireless system design has
increasingly turned its focus on guaranteeing reliability and latency. This
shifts the design objective of random access protocols from throughput
optimization towards constraints based on reliability and latency. For this
purpose, we use frameless ALOHA, which relies on successive interference
cancellation (SIC), and derive its exact finite-length analysis of the
statistics of the unresolved users (reliability) as a function of the
contention period length (latency). The presented analysis can be used to
derive the reliability-latency guarantees. We also optimize the scheme
parameters in order to maximize the reliability within a given latency. Our
approach represents an important step towards the general area of design and
analysis of access protocols with reliability-latency guarantees.Comment: Accepted for presentation at IEEE Globecom 201
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