A collaborative wireless access to on-demand services

A collaborative access scheme that exploits the broadcastnature of the wireless communication in order to achieve multicastcontent delivery is presented in this paper. The key idea is that individualclients requesting for the same content can collaborate and share the samedata channel. As opposed to broadcasting, this method enables the clientsto determine online the delivered content, and thus supports on-demandservices. On the other hand, a multicast content delivery is much moreefficient than a unicast content distribution, which must use a dedicateddata channel per each and every client. This method is particularlysuitable for sessions having a long-time duration, for applications in whichclients can subscribe to ahead of time, and for applications in which theclients receive the same information simultaneously. A multicast contentdistribution increases the network service throughput in terms of theexpected number of clients served simultaneously, and therefore it offersa reduced waiting time for content delivery at highly loaded time periods.It is shown that the problem of maximizing the efficiency of distributinga content in a wireless network is NP-hard. An approximation algorithmis therefore used, that for any 0<ε<1 finds an approximation solutionwith a relative accuracy ε. The proposed method does not require any hardware modification on the network equipment. Thus, it can be easilyimplemented.