4,123 research outputs found
Optimal CSMA-based Wireless Communication with Worst-case Delay and Non-uniform Sizes
Carrier Sense Multiple Access (CSMA) protocols have been shown to reach the
full capacity region for data communication in wireless networks, with
polynomial complexity. However, current literature achieves the throughput
optimality with an exponential delay scaling with the network size, even in a
simplified scenario for transmission jobs with uniform sizes. Although CSMA
protocols with order-optimal average delay have been proposed for specific
topologies, no existing work can provide worst-case delay guarantee for each
job in general network settings, not to mention the case when the jobs have
non-uniform lengths while the throughput optimality is still targeted. In this
paper, we tackle on this issue by proposing a two-timescale CSMA-based data
communication protocol with dynamic decisions on rate control, link scheduling,
job transmission and dropping in polynomial complexity. Through rigorous
analysis, we demonstrate that the proposed protocol can achieve a throughput
utility arbitrarily close to its offline optima for jobs with non-uniform sizes
and worst-case delay guarantees, with a tradeoff of longer maximum allowable
delay
Low-complexity medium access control protocols for QoS support in third-generation radio access networks
One approach to maximizing the efficiency of
medium access control (MAC) on the uplink in a future wideband
code-division multiple-access (WCDMA)-based third-generation
radio access network, and hence maximize spectral efficiency,
is to employ a low-complexity distributed scheduling control
approach. The maximization of spectral efficiency in third-generation
radio access networks is complicated by the need to
provide bandwidth-on-demand to diverse services characterized
by diverse quality of service (QoS) requirements in an interference
limited environment. However, the ability to exploit the full
potential of resource allocation algorithms in third-generation
radio access networks has been limited by the absence of a metric
that captures the two-dimensional radio resource requirement,
in terms of power and bandwidth, in the third-generation radio
access network environment, where different users may have
different signal-to-interference ratio requirements. This paper
presents a novel resource metric as a solution to this fundamental
problem. Also, a novel deadline-driven backoff procedure has
been presented as the backoff scheme of the proposed distributed
scheduling MAC protocols to enable the efficient support of
services with QoS imposed delay constraints without the need
for centralized scheduling. The main conclusion is that low-complexity
distributed scheduling control strategies using overload
avoidance/overload detection can be designed using the proposed
resource metric to give near optimal performance and thus maintain
a high spectral efficiency in third-generation radio access
networks and that importantly overload detection is superior to
overload avoidance
Wireless Network Stability in the SINR Model
We study the stability of wireless networks under stochastic arrival
processes of packets, and design efficient, distributed algorithms that achieve
stability in the SINR (Signal to Interference and Noise Ratio) interference
model.
Specifically, we make the following contributions. We give a distributed
algorithm that achieves -efficiency on all networks
(where is the number of links in the network), for all length monotone,
sub-linear power assignments. For the power control version of the problem, we
give a distributed algorithm with -efficiency (where is the length diversity of the link set).Comment: 10 pages, appeared in SIROCCO'1
Finite Horizon Online Lazy Scheduling with Energy Harvesting Transmitters over Fading Channels
Lazy scheduling, i.e. setting transmit power and rate in response to data
traffic as low as possible so as to satisfy delay constraints, is a known
method for energy efficient transmission.This paper addresses an online lazy
scheduling problem over finite time-slotted transmission window and introduces
low-complexity heuristics which attain near-optimal performance.Particularly,
this paper generalizes lazy scheduling problem for energy harvesting systems to
deal with packet arrival, energy harvesting and time-varying channel processes
simultaneously. The time-slotted formulation of the problem and depiction of
its offline optimal solution provide explicit expressions allowing to derive
good online policies and algorithms
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