Push systems are not suitable for applications with a priori unknown, dynamic client demands. This paper proposes an adaptive push-based system. It suggests the use of a learning automaton at the broadcast server to provide adaptivity to an existing push system while maintaining its computational complexity. Using simple feedback from the clients, the automaton continuously adapts to the client population demands so as to reflect the overall popularity of each data item. Simulation results are presented that reveal the superior performance of the proposed approach in environments with a priori unknown, dynamic client demands.

Proposed is an adaptive wireless push system capable of providing increased performance to single-receiver clients that exhibit locality of demand, when these are receiving data in a multichannel broadcasting environment.Introduction: Data broadcasting is an efficient way for dissemination of information over wireless environments, as the broadcast of one single information item will likely satisfy a large number of clients. Furthermore, certain applications can be characterised by locality of client demands (e.g. a traffic information system, where a driver is mainly interested in information regarding his neighbouring streets).In data broadcasting the primary performance metric is the client mean access time for a data item. When more than one frequency channel are available to the broadcast server (BS) for broadcasting data, existing methods, both for stationary [1] and dynamic environments [2], can offer a performance increase. However, they state that for Ch available frequency channels, the maximum performance increase is Ch-fold and is obtained when all the clients utilise Ch concurrent receivers [1]. The latter requirement however, is obviously a limiting factor when more than one frequency channel are available for broadcasting. To this end, this Letter proposes to exploit locality of demand in order to enable single-receiver clients to use more than one frequency channel when these are available for receiving broadcast data.

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A learning automata-based polling (LEAP) protocol for wireless LANs, capable of operating efficiently under bursty traffic conditions, is introduced. We consider an infrastructure wireless LAN, where the access point (AP) is located at the center of a cell which comprises a number of mobile stations. According to the proposed protocol, the mobile station that is granted permission to transmit is selected by the AP by means of a learning automaton. The learning automaton takes into account the network feedback information in order to update the choice probability of each mobile station. It is proved that the learning algorithm asymptotically tends to assign to each station a portion of the bandwidth proportional to the station's needs. LEAP is compared to the randomly addressed polling and group randomly addressed polling protocols and is shown to exhibit superior performance under bursty traffic.Index Terms-Bursty traffic, dynamic bandwidth allocation, learning automata-based polling (LEAP), wireless LANs.

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The combination of the most prestigious optical and wireless technologies for implementing a modern broadband integrated access network has been progressively gaining ground. By extending the network coverage in a cost-efficient way, hybrid wireless-optical networks are able to enclose a larger number of potential subscribers than standalone access architectures. Hence, they are capable of increasing revenue levels and facilitating commercial penetration to the telecom market. At the same time, hybrid wireless-optical networks pose an ambitious, alternative, and efficient solution to coping with new bandwidth-hungry user applications. Hybrid wireless-optical networks incorporate sophisticated modules, fabrics, and network entities to effectively provide adequate quality of service (QoS) provisioning. This survey endeavors to classify the main features of wireless-optical integration. We provide a comprehensive compilation of the latest architectures, integrated technologies, QoS features, and dynamic bandwidth allocation (DBA) schemes. In addition, new trends towards wireless-optical convergence are presented. Moreover, as the up-to-date hybrid network standards remain under development, since there is not yet an integrated standard for approving hybrid network access platforms, we accompany this survey with detailed challenges indicating potential avenues of future research.

Data broadcasting is an efficient way of delivering data to mobile clients having a high degree of commonality in their demand patterns. This paper proposes the use of multiple directional antennas to increase the performance of an adaptive wireless push system in environments that are characterized by the locality of client demands. Simulation results reveal that using up to three antennas suffices for a significant performance increase over the single-antenna adaptive wireless push system. Index Terms-Adaptive data broadcasting, directional antennas, locality of demand.