Congestion probabilities in CDMA-based networks supporting batched Poisson traffic

We propose a new multirate teletraffic loss model for the calculation of time and call congestion probabilities in CDMA-based networks that accommodate calls of different serviceclasses whose arrival follows a batched Poisson process. The latter is more "peaked" and "bursty" than the ordinary Poisson process. The acceptance of calls in the system is based on the partial batch blocking discipline. This policy accepts a part of the batch (one or more calls) and discards the rest if the available resources are not enough to accept the whole batch. The proposed model takes into account the multiple access interference, the notion of local (soft) blocking, user’s activity and the interference cancellation. Although the analysis of the model does not lead to a product form solution of the steady state probabilities, we show that the calculation of the call-level performance metrics, time and call congestion probabilities, can be based on approximate but recursive formulas. The accuracy of the proposed formulas are verified through simulation and found to be quite satisfactory

Do Auctions Select Efficient Firms?

This paper considers a government auctioning off multiple licenses to firms who compete in a market after the auction. Firms have different costs, and cost efficiency is private information at the auction stage and the market competition stage. If only one license is auctioned, standard results say that the most efficient firm wins the auction (license) as it will get the highest profit in the aftermarket, i.e., it has the highest valuation for the license. This paper argues that this result does not generalize to the case of multiple licenses and aftermarket competition. In particular, we determine conditions under which auctions may select inefficient firms and therefore lead to an inefficient allocation of resources. Strategic interactions in the aftermarket, in particular firms’ preferences to compete with the least cost-efficient firms rather than with the most efficient firms, are responsible for our result

National networks

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Assumptions Made for the British Telecom URI Project

This document describes in detail the assumptions which are to be made in defining the security architecture for the URI project. This work is important in that it helps to set the limits to the architecture's scope, gives a basis for informed critiques of the architecture, and provides the designers of implementations based on it with a series of rationales for making design decisions in the light of knowledge of the architecture's objectives. It will also provide a basis for modifying the architecture in a controlled manner should any of these assumptions become invalid over time due to experience or changes in the environment within which designs based on it are operating. This document, and the assumptions presented in it, are to be regarded as provisional conclusions only. As the project advances and knowledge of the environment within which implementations of the architecture will have to operate and the constraints placed on such implementations, these assumptions will need to be re-assessed either continuously or on a regular basis. Our assumptions have diverged in many ways from those in two documents prepared by British Telecom staff for the TINA consortium, [6] and [7]. The reasons for this can be broadly summarised as being due to our desire for independence for the architecture of all design and implementation technical matters, our taking a wider view in identifying the stakeholders in the architecture both with regard to their identities and their degree of sophistication in security-related matters, our belief that access to the services protected by the architecture must be as easy as possible to make it more likely that they will be used, and our assumption that not all of the entities involved in the network will trust each other. We hope that the com..

Stakeholders Better world - our commitment to society

This document is part of BT's Social and Environmental Report. Also available via the InternetAvailable from British Library Document Supply Centre-DSC:m02/39458 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Suppliers Better world - our commitment to society

This document is part of BT's Social and Environmental Report. Also available via the InternetAvailable from British Library Document Supply Centre-DSC:m02/39457 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Sustainability Better world - our commitment to society

This document is part of BT's Social and Environmental Report. Also available via the InternetAvailable from British Library Document Supply Centre-DSC:m02/39463 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Our customers Better world - our commitment to society

This document is part of BT's Social and Environmental Report. Also available via the InternetAvailable from British Library Document Supply Centre-DSC:m02/39460 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo