1o Seminário sobre Estudos e Aplicações da Teoria da Computação

O Grupo de Estudos e Aplicações da Teoria da Computação (GEATC) convida a comunidade acadêmica:

1^o Seminário sobre Estudos e Aplicações da Teoria da Computação

Data: terça-feira, 20/08/2013, às 16h

Local: mini auditório

Idioma da apresentação: português

Distributed Channel Allocation Algorithms for Access Point Based Return Channel in IDTV

 RESUMO:

An important social aspect of the Interactive Digital TV (IDTV) is to provide access to telecommunications networks through the use of the return channel, promoting digital inclusion. IEEE802.11 standards still are competitive technologies for the implementation of the return channel in suburban areas, because their low cost and ease of implementation. Considering an access point (AP) based architecture for the return channel, the channel allocation problem is investigated, in order to minimize interference and improve the network performance. The channel allocation problem is modeled as a DCOP (Distributed Constraint Optimization Problem). This research proposes and investigates four distributed algorithms for channel allocation. The first proposed algorithm, named DCAA-O, is synchronous and parallel which finds the optimal solution to the channel assignment problem for a group of APs. The second algorithm, called DCAA-S, is derived from DCAA-O. It achieves the suboptimal solution with the advantage of significantly reducing the number of exchanged control messages. The third and fourth algorithms, called DOCA and DSCA, reduce the number of messages and also the total amount of control information exchanged between APs. The DOCA algorithm achieves a globally optimal solution and requires a linear number of control messages. The DSCA algorithm, by reducing the size of the exchanged messages, presents a suboptimal solution and is more scalable than DOCA. The algorithms were compared to a recently proposed distributed protocol for channel allocation in WLANs, denoted Local-Coord (LO-A). All algorithms outperform LO-A in terms of solution quality in most scenarios.