4 research outputs found
On Throughput Maximization of Grant-Free Access with Reliability-Latency Constraints
Enabling autonomous driving and industrial automation with wireless networks
poses many challenges, which are typically abstracted through reliability and
latency requirements. One of the main contributors to latency in cellular
networks is the reservation-based access, which involves lengthy and
resource-inefficient signaling exchanges. An alternative is to use grant-free
access, in which there is no resource reservation. A handful of recent works
investigated how to fulfill reliability and latency requirements with different
flavors of grant-free solutions. However, the resource efficiency, i.e., the
throughput, has been only the secondary focus. In this work, we formulate the
throughput of grant-free access under reliability-latency constraints, when the
actual number of arrived users or only the arrival distribution are known. We
investigate how these different levels of knowledge about the arrival process
influence throughput performance of framed slotted ALOHA with -multipacket
reception, for the Poisson and Beta arrivals. We show that the throughput under
reliability-latency requirements can be significantly improved for the higher
expected load of the access network, if the actual number of arrived users is
known. This insight motivates the use of techniques for the estimation of the
number of arrived users, as this knowledge is not readily available in
grant-free access. We also asses the impact of estimation error, showing that
for high reliability-latency requirements the gains in throughput are still
considerable.Comment: Accepted for publication in ICC'201
Reliable Reporting for Massive M2M Communications with Periodic Resource Pooling
This letter considers a wireless M2M communication scenario with a massive
number of M2M devices. Each device needs to send its reports within a given
deadline and with certain reliability, e. g. 99.99%. A pool of resources
available to all M2M devices is periodically available for transmission. The
number of transmissions required by an M2M device within the pool is random due
to two reasons - random number of arrived reports since the last reporting
opportunity and requests for retransmission due to random channel errors. We
show how to dimension the pool of M2M-dedicated resources in order to guarantee
the desired reliability of the report delivery within the deadline. The fact
that the pool of resources is used by a massive number of devices allows to
base the dimensioning on the central limit theorem. The results are interpreted
in the context of LTE, but they are applicable to any M2M communication system.Comment: Submitted to journa
Analysis of d-ary Tree Algorithms with Successive Interference Cancellation
In this article, we calculate the mean throughput, number of collisions,
successes, and idle slots for random tree algorithms with successive
interference cancellation. Except for the case of the throughput for the binary
tree, all the results are new. We furthermore disprove the claim that only the
binary tree maximises throughput. Our method works with many observables and
can be used as a blueprint for further analysis.Comment: 30 pages, 2 figures, comments welcom
Analysis of Tree-Algorithms with Multi-Packet Reception
In this paper, we analyze binary-tree algorithms in a setup in which the
receiver can perform multi-packet reception (MPR) of up to and including K
packets simultaneously. The analysis addresses both traffic-independent
performance as well as performance under Poisson arrivals. For the former case,
we show that the throughput, when normalized with respect to the assumed linear
increase in resources required to achieve K-MPR capability, tends to the same
value that holds for the single-reception setup. However, when coupled with
Poisson arrivals in the windowed access scheme, the normalized throughput
increases with K, and we present evidence that it asymptotically tends to 1. We
also provide performance results for the modified tree algorithm with K-MPR in
the clipped access scheme. To the best of our knowledge, this is the first
paper that provides an analytical treatment and a number of fundamental
insights in the performance of tree-algorithms with MPR.Comment: Published in : GLOBECOM 2020 - 2020 IEEE Global Communications
Conferenc