Channel Occupancy Time Research Articles

A Model with Generalized Holding and Cell Residence Times for Evaluating Handoff Rates and Channel Occupancy Times in PCS Networks

This paper presents a performance model for apersonal communications services (PCS) system whichgeneralizes results obtained by the authors, allowingfor a more realistic computation of basic PCS network parameters. In particular, this modelgeneralizes the call holding time and the cell residencetime distributions. On the basis of this model, wederive the handoff rates and the channel occupationtimes, and show how these can be applied to computethe call blocking probabilities in these networks. Asimplified numerical example is presented to demonstratethe application of the presented approach.

A measurement-based prioritization scheme for handovers in mobile cellular networks

A method of improving the quality of service in mobile cellular systems based on prioritization of handover requests is presented. The objective is to improve perceived quality of cellular service by minimizing both the probability of forced termination of ongoing calls due to handover failures and the degradation in spectrum utilization. A model based on a multiple-priority nonpreemptive queuing discipline is developed. New calls are blocked if all channels are occupied. Handover requests are queued such that as soon as a channel is available, it is offered to the mobile subscriber with the measurement results closest to the minimum acceptable power level for communication. Service rate is given by channel occupancy time distribution and is assumed to be exponential. The performance of a cellular system employing the proposed handover policy is evaluated analytically and by simulation, and results are compared to those obtained when the cellular system employs nonprioritized call handling and first-in/first-out queuing discipline. This provides lower probability of forced termination and less call blocking, less reduction in traffic, and less delay. >

Channel occupancy time distribution in a cellular radio system

The distribution of the channel occupancy time in a cellular radio system is studied, namely, the distribution of the time spent by customers on one frequency channel within a given cell. Two approaches are used. The first one relies on a computer simulation allowing a general model for mobiles behavior. The second is analytical, and assume a simplified system where mobiles keep constant directions. The results of both methods are compared with a fitted exponential distribution, and excellent agreements are found for most practical situations. In addition, a simple expression giving the average number of handoffs for a random customer is obtained. The results derived in this paper provide useful and simple tools to analyze cellular systems.

Treatment of two phenomenological components in transverse relaxation of rapidly exchanging [formula omitted] cesium-133 nuclei to calculate correlation times

The transverse relaxation of spin- 7 2 cesium-133 ions when interacting with the Gramicidin channel exhibits a phenomenology of two exponential relaxation processes, the relative magnitudes of which vary with CsCl concentration. When the two phenomenological transverse relaxation times, T′ 2 and T″ 2, are used in the formalism for spin- 3 2 nuclei for calculating correlation times, very reasonable values of the correlation times are obtained as judged by their use in calculating Gramicidin single-channel currents. In particular a comparison with spin- 3 2 rubidium-87 transverse relaxation data and the facts that Rb + and Cs + exhibit very similar binding constants and single-channel currents provide a specific demonstration that, when two relaxation processes are observed for spin- 7 2 cesium-133, the use of the two transverse relaxation times in the spin- case3 2 formalism of Bull, Forsén, and colleagues gives rise to correlation times that quite accurately calculate single-channel currents when interpreted as channel occupancy times.

Psychological Refractoriness of Two Serial Motor Responses

Abstract The memory drum and single channel concepts of refractoriness were examined, using a forward lunge with a concurrent right-arm swing as the primary response and a right-thumb key release for the second response. Interstimulus intervals (ISIs) ranged from .10 to .50 sec. in 10-sec. steps; they were presented in a random order. While movement refractoriness decreased with ISI, no residual capacity was evident in examining the single channel model making channel occupation time equal to RT1. The possibility that CRT1 (central refractory time, 6) was of variable duration was also noted. The fact that the correlations between RT1 and RT2 implied little generality of individual differences emphasized the need for further research if single channel models are to achieve closer approximations to data arising from the study of the ability to execute consecutive paired responses.