Abstract
In 2008, Institute of Electrical and Electronics Engineers (IEEE) published its standard IEEE 802.21 for media-independent handover services. The main scope of this work was to design a technology agnostic mobility platform to perform vertical handovers between heterogeneous networks. Regarding vertical handover procedures, a key issue to address is the control of packet loss, which is responsible for high handover latency and low communication quality. The solution proposed by the standard IEEE 802.21 guarantees reliability by exploiting Automatic Repeat Request (ARQ). However, the use of an acknowledgement service has been demonstrated not to be the best way to handle frame loss. In this thesis, we propose a novel architecture and protocol to efficiently perform vertical handovers. This protocol is called Enhanced-Coded MIH (EC-MIH) and exploits Forward Error Correction (FEC) instead of ARQ. In fact, it performs built-in coding operations to handle erasures of MIH frames. Moreover, we designed a novel hybrid concatenated coding scheme called Hybrid Serial Concatenated Network Code (HSCNC), composed of the serial concatenation of a classical erasure code and systematic Random Linear Network Coding (RLNC). We show via theoretical analysis as well as MATLAB simulations that the concatenation approach can outperform RLNC alone in terms of decoding error probability. Moreover, this work analyses the frame loss of Media-Independent Handover (MIH) protocol during vertical handovers via system level simulations. The proposed HSCNC design is then integrated into the new EC-MIH protocol and evaluated. We then discuss how the new protocol outperforms the legacy protocol in terms of throughput (at TCP layer, above MIH) and handover delay.