The statistical average carrier-to-interference ratio (CIR) of an ad hoc CSMA/CA wireless network providing multiple service-classes

Abstract

This work characterizes the statistically expected carrier-tointerference ratio (CIR, C/R) of an ad hoc CSMA/CA wireless communication network, via Monte Carlo simulations. This paper is first in the open literature to model an ad hoc network accounting for all these following factors: (1) more realistic modeling of the network nodes' spatial distribution as via a two-dimensional Poisson process, whereby the network nodes are randomly placed arbitrarily on a two-dimensional plane (instead of the nodes locating deterministically at regularly spaced grid points), (2) suppression of nodes within the carrier-sensing range of a transmitting node, to micmac the CSMA/CA Medium Access Control (MAC) protocol (i.e. a node would self-restrain from transmission if close to a transmitting node), (3) microscopic Rayleigh fading, (4) propagation-distance-dependent path-loss, and (5) more than one service class. Monte Carlo simulations of a CSMA/CA ad hoc network generate the CIR data, whose statistical expected value and dependence on node's spatial Poisson intensity and relative power level are investigated. 1. THE CIR's SIGNIFICANCE & THE FACTORS AFFECTING THE CIR An ad hoc wireless communication network consists of a set of triansceiving nodes, routing each other's data packets without centralized control. An ad hoc network's performance metrics include its channel capacity, throughput, packet transmission time, queuing delay, transmission blocking probability [121, and outage probability. All these quality-of-service (QoS) perlormance metrics depend critically on the carrier-tointerierence ratio (CIR, C/R) at the network nodes. If the CIR is considered a stochastic variable, then each aforementioned QoS metric is also a stochastic entity, whose statistics depends on the CIR's statistics. Various propagation-channel parameters and networkprotocol factors affect this CIR, e.g., propagation-path loss in power, microscopic fading (often statistically modeled as Rayleigh distributed), the spatial distribution of the network's nodes, the network's number of service classes, the network's medium-access-control (MAC) protocol. More precisely, consider a kth-class transmission from node 'n0 to an intended node l transmitted with signal power Pkx) Node irix Tlhe authors were supported by Canada's Naitural Sciences & Engineering Research Council's Discovery Research Grant # NSERC-RGPIN-24977502 and the C;mnadian province of Ontario's 'Premier's Research Excellence Award". receives this signal at power: