Aqua-Sim-NG multichannel MAC implementation

Multichannel MAC implementation

• new aqua-sim-mac-multichannel module:

Modified TxProcess and RecvProcess methods of the AquaSimMac base class. Added channel division on N number of subchannels, depending on given bandwidth. By default, the following bandwidth is used and the following subchannels are created:

• bandwidth: 10 - 40 kHz
• step frequency: 3 kHz
• N of subchannels: 10

The following channel_id:frequency map is generated:

<channel_1 : 10 kHz>, <channel_2 : 13 kHz>, …, <channel_10 : 37 kHz>

• modified aqua-sim-phy-cmn module:

Modified recv() method of AquaSimPhyCmn class, which is used for both transmission and reception of the scheduled packet. The modified recv() method has a new argument - frequency, and is executed by upper multichannel-mac module, depending on the selected channel_id.

• modified aqua-sim-channel module:

Modified SendUp() method of AquaSimChannel class. Now this method gets a frequency value of the incoming packet, using AquaSimPacketStamp class and inserts it into the ::Recv() method of the AquaSimPhyCmn upon execution in the Scheduler.

Initial tests

For the initial tests the following simulation scenario was used:

“node_1 (sender)” <— 10m distance —> “node_2 (sink)”

The following stack was used on both nodes: - OnOffApplication — OffTime: 0, OnTime: 1 - Routing — Dummy (for MAC layer testing) - MultichannelMac — default bandwidth (10 - 40 kHz), 10 subchannels, 3kHz frequency step - PhyCmn — modified PhyCmn module

Some other parameters: - Simulation time: 10 seconds - Transmission range: 100 meters (for Phy module) - Distance: 10 meters (Mobility model)

In all tests a throughput was measured by defining an application data rate, higher than possible capacity of the given channel:

80 kbps dataRate parameter of OnOffApplication. Thus, the throughput was measured by counting a total amount of received packets:

throughput = total_received_packets * packet_size * 8 / 10, [bps]

where: 10 - simulation time, seconds.

1-st test

A single channel was used during entire simulation. - channel_id: 1, frequency: 10 kHz.

The throughput was measured, depending on varying packet length. The result is plotted on Fig.1.

Fig.1

Corresponding sent/received packet count is illustrated on Fig.2.

Fig.2

2-nd test

During the simulation, various channels were used in the following “round-robin” way:

• 1_packet: channel_1 (10kHz)
• 2_packet: channel_2 (13kHz)
• 3_packet: channel_3 (16kHz)
• 4_packet: channel_4 (19kHz)
• 5_packet: channel_5 (22kHz)
• 6_packet: channel_6 (25kHz)
• 7_packet: channel_7 (28kHz)
• 8_packet: channel_8 (31kHz)
• 9_packet: channel_9 (34kHz)
• 10_packet: channel_11 (37kHz)
• 11_packet: channel_1 (10kHz)
• …. etc.

The throughput is plotted on Fig.3.

Fig.3

Corresponding sent/received packet count is illustrated on Fig.4.

Fig.4

Code of simulation script can be found here:

multichannel_mac_example.cc