Homogenous handover with NIST WiMAX module in NS-2.31

Dear all

I am carrying out a layer 2 performance analyses of CBR and FTP traffics in mobile WiMAX for my project using the NIST WiMAX module (homogenous handover) with NS-2.31 on Linux Fedora Core 5. I want to measure throughput, delay, jitter and packet loss when mobile nodes moves within a base station and then handover latency, Blocking probability and Dropping probability when it moves from one base station to another (handover) by configuring different speeds, modulations, Frequency bandwidths and cyclic prefixes.

I have some results which I have analysed with trace graph but I am having problem with the handover aspect. I noticed in NAM, the trace file and from Trace Graph that the mobile node communicated with only base station 1 throughout the simulation. I did not see packets being received by base station 2. The manual says the lgd factor should be above 1 to trigger scanning but it is already set at 1.8. I increased the scanning trigger time by setting it to 2 but still could not achieve handover. Is it possible that there was a timeout while synchronization, ranging and registration was still going on for base station 2? I tried to manually create another channel and attach the mobile node to base station 2 with the “$ns at ” command, but when the mobile node sent ARP requests to base station 2, it kept being dropped!!

My questions are:

1) What do I do to achieve handover?

2) Can Trace graph do all my analyses based on the performance indicators (ie throughput, delay, jitter, packet loss, handover latency, Blocking probability and Dropping probability) stated above?

3) do you know of any implementation between WiMAX and satellite?

Your urgent help will really be appreciated!! Thanks so much for your time!

Best Regards
C. W. Emehel