I don't know who exactly ask it, but the way to set wireless link speed is here:
Your TCL file:
(...)
$ns_ node-config -adhocRouting PROTOCOL \
-llType LL \
-macType Mac/802_11 \
-ifqLen 50 \
-ifqType Queue/DropTail/PriQueue \
-antType Antenna/OmniAntenna \
-propType Propagation/TwoRayGround \
-phyType Phy/WirelessPhy \
-channel [new Channel/WirelessChannel] \
-topoInstance $topo \
-agentTrace ON \
-routerTrace ON \
-macTrace OFF
Mac/802_11 set PLCPDataRate_ 2.0e6 ;# 2Mbps
(...)
--
Sidney Doria
Redes ad hoc móveis
Mestrado em Computação
UFCG
Brasil
"Nessa jornada, o conhecimento será o seu escudo..."
(Mestre dos Magos no episódio do grimoire de ouro)