Efficiency and Dependability of Direct Mobile-to-Mobile Data Transfer for UMTS Downlink in Multi-Service Networks

This paper is a sequel of previous work, in which we proposed a concept based on direct mobile-to-mobile (m2m) data exchange on uplink channels for distribution of large popular content in dynamic wireless environment. We showed the feasibility and performance benefit of m2m file sharing applications in terms of thereby released overall downlink capacity in UTRA-FDD systems, where multiple m2m user groups coexist in the network. A pure m2m traffic scenario was investigated and the wireless interference only among the neighboring groups was taken into account. The present paper extends the basic model by introducing a hybrid case of traffic. We consider an UMTS system scenario with coexisting conventional UMTS users and m2m file sharing participants and analyze the cross-traffic impact in order to find out the degree of m2m data transfer performance degradation due to increased uplink interference. The results indicate a slight performance degradation of m2m file sharing applications, in terms of relative losses of m2m link quality (number of corrupted data) caused by additional interference from cross-traffic. Nevertheless, no dramatic decrease in service probability and overall throughput for m2m applications in an UMTS network was observed. Furthermore, results show that by a well-designed m2m routing policy the ability to interconnect wireless devices on the partly unused uplink carrier frequencies (due to typical asymmetric uplink/downlink traffic load) might be a profitable goal and offers a promising alternative for distribution of popular content.