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We investigate an ad hoc network where node locations are distributed according to a homogeneous Poisson process with intensity λ. We assume that all the nodes are equipped with an identical wireless transceiver capable of operating satisfactorily up to a certain maximal link loss. Our link model depends on the length of the link and on random log-normal fading. Each node functions as a source and a destination of data packets and may also serve as a repeater to transport the packets over multihop routes, as determined by the network router. We study two important properties of the network. The first is connectivity, viz., given the peak transmit power of a node, the probability that a node cannot communicate with a random destination node at distance D when at most t hops are allowed. We provide the exact analytical results for t = 1 and t = 2 and an iterative lower bound for t > 2. We calculate the average number of hops of the minimum-hop-count route between a source and a destination at a distance D apart. The second property relates to power consumption--an important parameter when the nodes are battery operated. We derive the cumulative distribution function of the total transmit energy required per data packet when the distance between the source and the destination node is D, and only one or at most two hops, are allowed. We graphically show the benefit of allowing two hops over just one. [ABSTRACT FROM AUTHOR]

In this paper, we study a large network of subscriber stations (SSs) with certain common wireless capabilities and base stations (BSs) having direct connections to the wired infrastructure in addition to common wireless capabilities. SSs can communicate with the ‘outside world’ only through the BSs. Connections to SSs without a direct (i.e., a single hop) wireless connection to any BS are established, if possible, through other SSs serving as wireless repeaters. The locations of the SSs and the BSs follow independent homogeneous planar Poisson processes. The propagation channels exhibit signal attenuation with distance and log—normal shadowing. We evaluate exactly the probability of an SS to have a direct wireless connection to any of the BSs and a lower bound on the t-hop (t arbitrary) outage probability of an SS. We then define the minimal hop-count routing algorithm and calculate the mean number of hops for routes connecting SSs to BSs, when a maximum hop-count constraint is imposed. We compute next the probability distribution of the transmit power under the assumption of perfect power control. We conclude by calculating a bound for the total mean transmit energy required to transfer a data packet from an SS to a BS over a minimal hop-count route and show that this energy is significantly lower than the corresponding value in a single-hop network operating at the same outage probability. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of two control parameters of the Universal Mobile Telecommunications System (UMTS) handoff algorithm on the total peak base station (BS) transmit power required per mobile station (MS) to satisfy a prescribed outage probability. Denoting the set of BSs supporting an MS in soft handoff (SH) as the active group, the first parameter n is the maximum allowed size of the active group. The second, denoted r, is the upper limit on the difference between the path loss of the dominant BS and that of any other member of the active group, where the term "dominant" refers to the BS with the lowest path loss to the MS. It was assumed that the MS is equipped with a Rake receiver capable of performing "maximal ratio combining" of the signals it receives from the transmitting BSs. General analytical derivations along with results derived for specific situations through numerical integration are presented. [ABSTRACT FROM AUTHOR]

Investigates the dynamics of the path losses between a mobile terminal and a small group of base stations. Effect of local averaging on the underlying Gudmundson process; Methodology; Results and discussion.

Proposes a sector beam synthesis technique for cellular systems using phased antenna arrays. Design criterion of maximum beam efficiency subject to a constraint on in-sector ripple; Demonstration of the utility of the proposed method; Conclusion.

Abstract: We address the problem of downlink throughput improvement for IEEE 802.11a/g systems by using a modified access point equipped with multiple antennas. The main restriction is that the standard terminals should not be modified in any way. An alternating time-offset space division multiple access (SDMA) solution is proposed for a conference room scenario. A simulation is based on channel models approved by the IEEE 802.11 Standards Group and takes into account the main features of the IEEE 802.11a/g standard. It is demonstrated that a near doubling of downlink capacity can be achieved in a conference room environment. [Copyright &y& Elsevier]