222,052 research outputs found
Energy-delay bounds analysis in wireless multi-hop networks with unreliable radio links
Energy efficiency and transmission delay are very important parameters for
wireless multi-hop networks. Previous works that study energy efficiency and
delay are based on the assumption of reliable links. However, the unreliability
of the channel is inevitable in wireless multi-hop networks. This paper
investigates the trade-off between the energy consumption and the end-to-end
delay of multi-hop communications in a wireless network using an unreliable
link model. It provides a closed form expression of the lower bound on the
energy-delay trade-off for different channel models (AWGN, Raleigh flat fading
and Nakagami block-fading) in a linear network. These analytical results are
also verified in 2-dimensional Poisson networks using simulations. The main
contribution of this work is the use of a probabilistic link model to define
the energy efficiency of the system and capture the energy-delay trade-offs.
Hence, it provides a more realistic lower bound on both the energy efficiency
and the energy-delay trade-off since it does not restrict the study to the set
of perfect links as proposed in earlier works
On the Throughput-Delay Trade-off in Georouting Networks
We study the scaling properties of a georouting scheme in a wireless
multi-hop network of mobile nodes. Our aim is to increase the network
capacity quasi linearly with while keeping the average delay bounded. In
our model, mobile nodes move according to an i.i.d. random walk with velocity
and transmit packets to randomly chosen destinations. The average packet
delivery delay of our scheme is of order and it achieves the network
capacity of order . This shows a practical
throughput-delay trade-off, in particular when compared with the seminal result
of Gupta and Kumar which shows network capacity of order and
negligible delay and the groundbreaking result of Grossglausser and Tse which
achieves network capacity of order but with an average delay of order
. We confirm the generality of our analytical results using
simulations under various interference models.Comment: This work has been submitted to IEEE INFOCOM 201
Throughput-Delay Trade-off for Hierarchical Cooperation in Ad Hoc Wireless Networks
Hierarchical cooperation has recently been shown to achieve better throughput
scaling than classical multihop schemes under certain assumptions on the
channel model in static wireless networks. However, the end-to-end delay of
this scheme turns out to be significantly larger than those of multihop
schemes. A modification of the scheme is proposed here that achieves a
throughput-delay trade-off for T(n) between
and , where D(n) and T(n) are
respectively the average delay per bit and the aggregate throughput in a
network of n nodes. This trade-off complements the previous results of El Gamal
et al., which show that the throughput-delay trade-off for multihop schemes is
given by D(n)=T(n) where T(n) lies between and .
Meanwhile, the present paper considers the network multiple-access problem,
which may be of interest in its own right.Comment: 9 pages, 6 figures, to appear in IEEE Transactions on Information
Theory, submitted Dec 200
Restricted Mobility Improves Delay-Throughput Trade-offs in Mobile Ad-Hoc Networks
In this paper we revisit two classes of mobility models which are widely used to repre-sent users ’ mobility in wireless networks: Random Waypoint (RWP) and Random Direction (RD). For both models we obtain systems of partial differential equations which describe the evolution of the users ’ distribution. For the RD model, we show how the equations can be solved analytically both in the stationary and transient regime adopting standard mathematical techniques. Our main contributions are i) simple expressions which relate the transient dura-tion to the model parameters; ii) the definition of a generalized random direction model whose stationary distribution of mobiles in the physical space corresponds to an assigned distribution
Delay-Energy lower bound on Two-Way Relay Wireless Network Coding
Network coding is a novel solution that significantly improve the throughput
and energy consumed of wireless networks by mixing traffic flows through
algebraic operations. In conventional network coding scheme, a packet has to
wait for packets from other sources to be coded before transmitting. The
wait-and-code scheme will naturally result in packet loss rate in a finite
buffer. We will propose Enhanced Network Coding (ENC), an extension to ONC in
continuous time domain.
In ENC, the relay transmits both coded and uncoded packets to reduce delay.
In exchange, more energy is consumed in transmitting uncoded packets. ENC is a
practical algorithm to achieve minimal average delay and zero packet-loss rate
under given energy constraint. The system model for ENC on a general renewal
process queuing is presented. In particular, we will show that there exists a
fundamental trade-off between average delay and energy. We will also present
the analytic result of lower bound for this trade-off curve, which can be
achieved by ENC
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