NATO Narrowband Waveform (NBWF) - performance analysis of complex networks

NATO is in the process of finishing edition 1 of the narrowband waveform (NBWF) STANAGs 5630 to 5633. NBWF provides ground-to-ground communication between troops/platforms at the tactical battlefield using the military VHF and UHF band (30 – 500 MHz). NBWF is a singlechannel mobile ad-hoc radio network (MANET) which shall serve voice and data traffic using radio frequency (RF) bandwidth less than 100 kHz, primarily 25 kHz. FFI has participated in the NBWF standardisation activity for a number of years, and many simulation experiments have been executed to analyse different technical solutions. In our earlier simulation experiments, we analysed simple NBWF networks with few radio nodes. Now we extend the network size (number of nodes) and use scenarios with more demanding radio conditions. The experimental results obtained through simulations did not discover any anomalous behaviour of the NBWF protocols. As a network increases in size, the routing traffic increases also. The simulator used did not model the NBWF routing protocols, but used static routing. We expect that the routing protocol is the protocol that would be the major obstacle to deploy large networks. As an NBWF network turns from a fully meshed topology with single-hop traffic to a multi-hop scenario with hidden nodes, the NBWF protocol efficiency decreases. By gradually decreasing the radio range, we illustrated how the network throughput decreases with reduced radio coverage. Multi-hop IP-streams consume more transmission capacity than single-hop IP-streams and therefore, the network throughput must decrease. The simulation experiments showed that it is the medium access reservation protocol that gets the toughest operating conditions in the scenarios analysed due to the hidden node problem.

Nato har en pågående aktivitet der det skal utvikles en smalbånds radiobølgeform (NBWF) standard (STANAG). NBWF er et ad-hoc nettverk der nodene kommuniserer over en en-kanals radiokanal med RF-båndbredde mindre enn 100kHz. FFI har deltatt i NBWF-standardiseringsarbeidet i mange år. Forskjellige tekniske løsninger har blitt analysert basert på data fra simuleringseksperimenter. Tidligere analyser har bare vært utført på enkle nettopologier. Denne rapporten utvider kompleksiteten både ved å øke antall noder og ved å innføre redusert radiodekning. Virkningsgraden til NBWF-protokollene må nødvendigvis gå ned etter hvert som radiodekningen reduseres og nettet får flerhoppsruter og skjulte noder. NBWF-protokollene viser ingen unormal oppførsel og gir en gradvis reduksjon i ytelsen etter hvert som radiodekningen blir dårligere.