Implementation of a multi-hop network at the university campus using an IEEE 802.11af-compliant Network

Information dissemination is a major problem during calamities as road networks, power lines, and communication infrastructures were damaged. The aforementioned challenge contributes to an inefficient and sluggish rescue and relief operations as miscommunication between the government, ground personnel and victims arise. Establishing a communication link in the TV White Space (TVWS) has been popular after numerous studies have shown the inefficient utilization of the TV bands. More TV spectrum was made available by the analog to digital switchover of TV broadcast which in the Philippines began in 2009. Results of the studies conducted in the Philippines showed availability of 46% to 62% TVWS in an urban area while 60% to 80% in rural area. TVWS has better propagation characteristics as compared to the ordinary Wi-Fi systems operating at 2.4 GHz and 5 GHz ISM band. In this study, the feasibility of a multi-hop network based on IEEE 802.11af standard as an alternative communication infrastructure was implemented and evaluated. Multi-hop implementation was viewed as a necessary approach to re-route the radio link around the presence of high obstruction and to increase coverage area. Adjacent, co-channel and intermodulation issue were experienced and addressed in this experiment. Results show that the deployed network attained a maximum throughput of 4.81 Mbps for uplink and 4.93 Mbps for downlink over 600 m using a single channel centered at 593 MHz. Its quality of service is seriously affected by rain with an observed drop in throughput by 17.76% although there was hardly a change in the measured RSSI. The system was able to successfully support voice and data transmission via Skype.