10 research outputs found
Dynamic Packet Scheduling in Wireless Networks
We consider protocols that serve communication requests arising over time in
a wireless network that is subject to interference. Unlike previous approaches,
we take the geometry of the network and power control into account, both
allowing to increase the network's performance significantly. We introduce a
stochastic and an adversarial model to bound the packet injection. Although
taken as the primary motivation, this approach is not only suitable for models
based on the signal-to-interference-plus-noise ratio (SINR). It also covers
virtually all other common interference models, for example the multiple-access
channel, the radio-network model, the protocol model, and distance-2 matching.
Packet-routing networks allowing each edge or each node to transmit or receive
one packet at a time can be modeled as well.
Starting from algorithms for the respective scheduling problem with static
transmission requests, we build distributed stable protocols. This is more
involved than in previous, similar approaches because the algorithms we
consider do not necessarily scale linearly when scaling the input instance. We
can guarantee a throughput that is as large as the one of the original static
algorithm. In particular, for SINR models the competitive ratios of the
protocol in comparison to optimal ones in the respective model are between
constant and O(log^2 m) for a network of size m.Comment: 23 page
Stable routing scheduling algorithms in multi-hop wireless networks
Stability is an important issue in order to characterize the performance of a network, and it has become a major topic of study in the last decade. Roughly speaking, a communication network system is said to be stableif the number of packets waiting to be delivered (backlog) is finitely bounded at any one time.
In this paper we introduce a number of routing scheduling algorithms which, making use of certain knowledge about the network’s structure, guarantee stability for certain injection rates.
First, we introduce two new families of combinatorial structures, which we call universally strong selectorsand generalized universally strong selectors, that are used to provide a set of transmission schedules. Making use of these structures, we propose two local-knowledgepacket-oblivious routing scheduling algorithms. The first proposed routing scheduling algorithm onlyneeds to know some upper bounds on the number of links and on the network’s degree, and is asymptotically optimal regarding the injection rate for which stability is guaranteed. The second proposed routing scheduling algorithm isclose to be asymptotically optimal, but it only needs to know an upper bound on the number of links. For such algorithms, we also provide some results regarding both the maximum latencies and queue lengths. Furthermore, we also evaluate how the lack of global knowledge about the system topology affects the performance of the routing scheduling algorithms.Funding for open access charge: CRUE-Universitat Jaume
Optimizing the Age-of-Information for Mobile Users in Adversarial and Stochastic Environments
We study a multi-user downlink scheduling problem for optimizing the
freshness of information available to users roaming across multiple cells. We
consider both adversarial and stochastic settings and design scheduling
policies that optimize two distinct information freshness metrics, namely the
average age-of-information and the peak age-of-information. We show that a
natural greedy scheduling policy is competitive with the optimal offline policy
in the adversarial setting. We also derive fundamental lower bounds to the
competitive ratio achievable by any online policy. In the stochastic
environment, we show that a Max-Weight scheduling policy that takes into
account the channel statistics achieves an approximation factor of for
minimizing the average age of information in two extreme mobility scenarios. We
conclude the paper by establishing a large-deviation optimality result achieved
by the greedy policy for minimizing the peak age of information for static
users situated at a single cell.Comment: arXiv admin note: text overlap with arXiv:2001.0547
Packet latency of deterministic broadcasting in adversarial multiple access channels
We study broadcasting in multiple access channels with dynamic packet
arrivals and jamming. Communication environments are represented by adversarial
models that specify constraints on packet arrivals and jamming. We consider
deterministic distributed broadcast algorithms and give upper bounds on the
worst-case packet latency and the number of queued packets in relation to the
parameters defining adversaries. Packet arrivals are determined by a rate of
injections and a number of packets that can be generated in one round. Jamming
is constrained by a rate with which an adversary can jam rounds and by a number
of consecutive rounds that can be jammed