Pricing in 3G and other communication networks may control and manage the utilisation of network resources. The available network resources get strained with increased usage levels, which results in poor service to the users. Most users prefer receiving high quality services at affordable costs. This requires the provision of QoS guarantees for network services at a low cost. In a real business scenario, this relationship is hard to achieve; moreover revenue sources for network operators have been shifting from the provision of network access to provisioning of rich services, e.g. multimedia services. To attain a functional compromise, we propose a pricing scheme that relies on service profiles to manage resource utilisation in a DiffServ-enabled 3G network. The service profiles define the QoS achieved for accessing services through a common resource pool, in which resource sharing is used to maximise network resource utilisation, user satisfaction and profits for the network operators. In an NGN scenario users would select pricing profiles according to their budgets, and the network will map these profiles to a set of QoS options that may translate to the choice of an access network for service access. In this paper, we present the mathematical model of the proposed pricing scheme, the proposed design of an evaluation framework, QoS performance results, and a service provisioning scenario illustrating the applicability of the proposed pricing scheme.

No abstract

Spatially multiplexed multiple-input-multiple-output orthogonal frequency division multiplexing (SM-MIMO-OFDM) systems are expected to provide a considerable increase of transmission capacity paving the way for the next generation broadband wireless communication standards. Considered MIMO-OFDM receiver performs estimation of the channel state information based on transmission of pilots concurrently with data symbols. The channel estimates are subsequently used for data detection. In this paper we discuss optimal placement and number of pilot subcarriers and derive the closed-form expression for the optimal power allocation between pilot and data symbols. The latter factor is important as under total transmit energy constraint there is a trade-off between boosting power of the pilot symbols to gain more accurate channel estimates and maintaining higher signal-to-noise ratio at the data subcarriers to minimise probability of detection error in the assumption of sufficiently reliable channel state information. KeywordsSpatial multiplexing, multipath channels, minimum mean squared error, pilot-to-data power ratio

No abstract

No abstract