1,207 research outputs found
Energy efficiency of some non-cooperative, cooperative and hybrid communication schemes in multi-relay WSNs
In this paper we analyze the energy efficiency of single-hop, multi-hop, cooperative selective decode-and-forward, cooperative incremental decode-and-forward, and even the combination of cooperative and non-cooperative schemes, in wireless sensor networks composed of several nodes. We assume that, as the sensor nodes can experience either non line-of-sight or some line-of-sight conditions, the Nakagami-m fading distribution is used to model the wireless environment. The energy efficiency analysis is constrained by a target outage probability and an end-to-end throughput. Our results show that in most scenarios cooperative incremental schemes are more energy efficient than the other methods
Diversity-Multiplexing Tradeoffs in MIMO Relay Channels
A multi-hop relay channel with multiple antenna terminals in a quasi-static
slow fading environment is considered. For both full-duplex and half-duplex
relays the fundamental diversity-multiplexing tradeoff (DMT) is analyzed. It is
shown that, while decode-and-forward (DF) relaying achieves the optimal DMT in
the full-duplex relay scenario, the dynamic decode-and-forward (DDF) protocol
is needed to achieve the optimal DMT if the relay is constrained to half-duplex
operation. For the latter case, static protocols are considered as well, and
the corresponding achievable DMT performance is characterized.Comment: To appear at IEEE Global Communications Conf. (Globecom), New
Orleans, LA, Nov. 200
Characterization of the on-body path Loss at 2.45 GHz and energy efficient WBAN design for dairy cows
Wireless body area networks (WBANs) provide promising applications in the healthcare monitoring of dairy cows. The characterization of the path loss (PL) between on-body nodes constitutes an important step in the deployment of a WBAN. In this paper, the PL between nodes placed on the body of a dairy cow was determined at 2.45 GHz. Finite-difference time domain simulations with two half-wavelength dipoles placed 20 mm above a cow model were performed using a 3-D electromagnetic solver. Measurements were conducted on a live cow to validate the simulation results. Excellent agreement between measurements and simulations was achieved and the obtained PL values as a function of the transmitter-receiver separation were well fitted by a lognormal PL model with a PL exponent of 3.1 and a PL at reference distance ( 10 cm) of 44 dB. As an application, the packet error rate ( PER) and the energy efficiency of different WBAN topologies for dairy cows (i.e., single-hop, multihop, and cooperative networks) were investigated. The analysis results revealed that exploiting multihop and cooperative communication schemes decrease the PER and increase the optimal payload packet size. The analysis results revealed that exploiting multihop and cooperative communication schemes increase the optimal payload packet size and improve the energy efficiency by 30%
Power Allocation and Cooperative Diversity in Two-Way Non-Regenerative Cognitive Radio Networks
In this paper, we investigate the performance of a dual-hop block fading
cognitive radio network with underlay spectrum sharing over independent but not
necessarily identically distributed (i.n.i.d.) Nakagami- fading channels.
The primary network consists of a source and a destination. Depending on
whether the secondary network which consists of two source nodes have a single
relay for cooperation or multiple relays thereby employs opportunistic relay
selection for cooperation and whether the two source nodes suffer from the
primary users' (PU) interference, two cases are considered in this paper, which
are referred to as Scenario (a) and Scenario (b), respectively. For the
considered underlay spectrum sharing, the transmit power constraint of the
proposed system is adjusted by interference limit on the primary network and
the interference imposed by primary user (PU). The developed new analysis
obtains new analytical results for the outage capacity (OC) and average symbol
error probability (ASEP). In particular, for Scenario (a), tight lower bounds
on the OC and ASEP of the secondary network are derived in closed-form. In
addition, a closed from expression for the end-to-end OC of Scenario (a) is
achieved. With regards to Scenario (b), a tight lower bound on the OC of the
secondary network is derived in closed-form. All analytical results are
corroborated using Monte Carlo simulation method
- …