404 research outputs found
Relay-assisted Multiple Access with Full-duplex Multi-Packet Reception
The effect of full-duplex cooperative relaying in a random access multiuser
network is investigated here. First, we model the self-interference incurred
due to full-duplex operation, assuming multi-packet reception capabilities for
both the relay and the destination node. Traffic at the source nodes is
considered saturated and the cooperative relay, which does not have packets of
its own, stores a source packet that it receives successfully in its queue when
the transmission to the destination has failed. We obtain analytical
expressions for key performance metrics at the relay, such as arrival and
service rates, stability conditions, and average queue length, as functions of
the transmission probabilities, the self interference coefficient, and the
links' outage probabilities. Furthermore, we study the impact of the relay node
and the self-interference coefficient on the per-user and aggregate throughput,
and the average delay per packet. We show that perfect self-interference
cancelation plays a crucial role when the SINR threshold is small, since it may
result to worse performance in throughput and delay comparing with the
half-duplex case. This is because perfect self-interference cancelation can
cause an unstable queue at the relay under some conditions.Comment: Accepted for publication in the IEEE Transactions on Wireless
Communication
Random Matrix Theory applied to the Estimation of Collision Multiplicities
This paper presents two techniques in order to estimate the collision multiplicity, i.e., the number of users involved in a collision [1]. This estimation step is a key task in multi-packet reception approaches and in collision resolution techniques. The two techniques are proposed for IEEE 802.11 networks but they can be used in any OFDM-based system. The techniques are based on recent advances in random matrix theory and rely on eigenvalue statistics. Provided that the eigenvalues of the covariance matrix of the observations are above a given threshold, signal eigenvalues can be separated from noise eigenvalues since their respective probability density functions are converging toward two different laws: a Gaussian law for the signal eigenvalues and a Tracy-Widom law for the
noise eigenvalues. The first technique has been designed for the white noise case, and the second technique has been designed for the colored noise case. The proposed techniques outperform current estimation techniques in terms of mean square error. Moreover, this paper reveals that, contrary to what is generally assumed in current multi-packet reception techniques, a single observation of the colliding signals is far from being sufficient to
perform a reliable estimation of the collision multiplicities
PHY-MAC dialogue with multi-packet reception
Cross-layer design has been considered
recently as a new approach when designing MAC
protocols in systems with diversity such as CDMA.
This paper goes one step further in the cross layer
design by proposing a PHY-MAC dialogue involving
the exchange of parameters such as BER and active
users. By means of this PHY-MAC dialogue, system
performance can be improved. A two-stage receiver is
used at PHY level. The first stage tracks active users
while the second stage is a data demodulator. The
Modified Dynamic Queue Protocol (MDQP) is
proposed as the MAC protocol of our system. When
the knowledge of active users is possible, it is
demonstrated by simulations that MDQP outperforms
DQP.Postprint (published version
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
Performance analysis of interference-aware multi-packet reception networks
This work is supported by the European Regional Development Fund (FEDER), through the Competitiveness and Internationalization Operational Programme (COMPETE 2020) of the Portugal 2020 and Programa Operacional Regional LISBOA (LISBOA 2020), and by national funds through Fundação para a Ciência e Tecnologia (FCT), under the projects CoSHARE (LISBOA-01-0145-FEDER-0307095-PTDC/EEITEL/30709/2017), InfoCent-IoT (POCI-01-0145-FEDER-030433), and project UID/EEA/50008/2019.Decentralized wireless networks are gaining increasing popularity as they do not need a fixed infrastructure. Simultaneously, multiple research initiatives have led to different findings at the PHY layer of the wireless communication systems, which include Multi-Packet Reception (MPR) techniques that enable a receiver to decode multiple packets that are transmitted simultaneously. However, the distributed nature of decentralized wireless networks demands different network control policies that should take into account the MPR capabilities to increase the network performance. This work studies the performance of a wireless network composed of multiple transmitters that are willing to transmit to a single receiver. This receiver has MPR capability and adopts an Energy-based Sensing (EBS) technique to enable uplink users’ transmissions without interfering with the ongoing transmissions from other transmitters. The first remark to be made is that the MPR technique performance depends on the channel propagation conditions and on the amount of time the receiver needs to detect the spectrum’s occupancy state. However, it is shown that by increasing the number of samples needed to increase the sensing accuracy, the receiver may degrade its throughput, namely if the receiver is equipped with a single radio, that is sequentially used for sensing and transmitting (split-phase operation). The results presented in the paper show the impact of the channel propagation condition and EBS parameterization on wireless network throughput and the cases where the receiver MPR capture performance is greatly improved by the use of a spectrum sensing technique.publishersversionpublishe
Effects of MAC Approaches on Non-Monotonic Saturation with COPE - A Simple Case Study
We construct a simple network model to provide insight into network design strategies. We show that the model can be used to address various approaches to network coding, MAC, and multi-packet reception so that their effects on network throughput can be evaluated. We consider several topology components which exhibit the same non-monotonic saturation behavior found within the Katti et. al. COPE experiments. We further show that fairness allocation by the MAC can seriously impact performance and cause this non-monotonic saturation. Using our model, we develop a MAC that provides monotonic saturation, higher saturation throughput gains and fairness among flows rather than nodes. The proposed model provides an estimate of the achievable gains for the cross-layer design of network coding, multi-packet reception, and MAC showing that super-additive throughput gains on the order of six times that of routing are possible.United States. Dept. of Defense (Air Force Contract FA8721-05-C-0002)Irwin Mark Jacobs and Joan Klein Jacobs Presidential FellowshipInformation Systems of ASD(R&E
Successful Packet Reception Analysis in Multi-Packet Reception Wireless Systems
In this letter, we analyze the individual probability of receiving a packet when nodes transmit simultaneously to a single receiver and a multi-packet reception (MPR) scheme is adopted at the physical layer. The main contribution of this letter is the characterization of the average number of packets successfully received. The generic methodology proposed to compute the probability of successful reception of a packet is obtained taking into account the stochastic nature of the path loss due to the spatial distribution of the nodes, as well as shadowing and fast fading effects. The accuracy of the theoretical approach is finally assessed through simulations, showing that for a generic MPR system, there is an optimal number of transmitters that maximize the average number of received packets
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