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We investigate an ad hoc network where node locations are distributed according to a homogeneous Poisson process with intensity [lambda]. 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 muter. 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. Index Terms--Multihop network, outage probability, routing, transmit energy.

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. Index Terms--Multihop network, outage probability, routing, transmit energy.

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 [tau] 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. Index Terms--Active group, outage, site selection diversity transmission, soft handoffs, UMTS.

We investigate the dynamics of the path losses between a mobile terminal and a small group of base stations, when the mobile traverses an area containing zones where different base stations have the least path loss to the mobile. While moving through the area, the mobile measures signals transmitted by each base station. The measurements involve calculating a running average of the measured signal power over a fixed time period. It is presumed that based on these measurements and typically other inputs, the wireless network supporting the mobile makes handoff decisions. In this paper, we do not attempt to analyze the performance of a practical handoff algorithm. Instead, we focus on the average number of times per meter traveled that a moving mobile must switch base stations in order to be always served by the base station with the least path loss. The switching rate is a function of the mobiles location with respect to the base stations and the velocity of the mobile. For low velocities, the multipath fading is not averaged out completely and, therefore, affects the measured results, while at high velocities the multipath fading is averaged out, but the resolution of the measurement is compromised, and any possible handoff will be delayed (in terms of location). In the sequel, we assume that the multipath fading has been averaged out, so we have a simple propagation channel model composed of two parts: a distance attenuation and a shadow loss. We also assume the validity of certain correlation and autocorrelation models describing statistical relationships between the path losses of the links involved. Index Terms--Cellular systems, handoffs.

Cell sectorization is used extensively to increase the capacity of cellular systems; however, intersector interference caused by nonideal sector antennas limits full realization of sectorization benefits. In this paper, we propose a new technique for sector beam synthesis using phased antenna arrays. We adopt the criterion of minimizing intersector interference, subject to a peak-to-peak ripple constraint on the in-sector power pattern. Spectral factorization permits a reparameterization yielding an easily solved fractional linear program. The proposed procedure accommodates nonisotropic antenna elements, arbitrary element spacing, and arbitrary sector boundaries, but is limited to uniformly spaced linear arrays. To demonstrate the utility of the proposed method, it is used to predict antenna array size requirements for a direct-sequence code-division multiple-access (DS-CDMA) cellular system. Index Terms--Fractional linear programming, magnitude design, sector beam synthesis, sectorized cellular systems.