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Michael May's blog

05

Jul

2013

Over the past while I have begun working on the MAC side of things in ns-3. I have started implementing a 802.11ad access point by getting a standards compliant beacon Transmission Interval working. This cycles through defined antennas and their sectors and transmits through the standard medium access method. I'm currently working on a beacon specific channel access method that contends for medium access and then transmits beacons for that interval without contention.
I have also been looking at extend the RadioTap standard to support 802.11ad features but the work involved is too much to carry on with at this stage.

07

Jun

2013

This week has been particularly short for me as I came down with a cold on Monday and it plagued me all week. I did manage to merge my code with the latest release of ns-3 with no problems. I also had a go at trimming ns-3 of modules I don't particularly need such as LTE and WiMAX but it seems most of the included modules are tightly integrated with the whole system and it doesn't like it when you fiddle around. I have also been getting some presentation material in place for the inevitable WAND talk I will have to give at some point.

31

May

2013

The PHY and channel objects are pretty much done and for the last little while I have been throughput testing and debugging. Initially using a 1.155 Gbps PHY I was reaching only 33 Mbps of measured throughput with a 1500 octet TCP bulk sending application. Moving to UDP speed things up to 100 or so Mbps. Converting the transmit duration calculations from microseconds to nanoseconds speed things up again. After that it was a lot of head banging to realise that the single line of throughput reporting was outputting in Mebibits instead of Megabits. Also getting the exact time in nanoseconds of the UDP flow from when the first packet is received to the last helped bring in the reported throughput to less than 1% difference from the theoretical throughput based on the simulations average number of backoff slots. This difference should be accounted for due to beacon transmissions.

13

May

2013

It's been awhile since I've posted but over the last few weeks I have studied over the 802.11ad standard and its particulars, along with a detailed review of the wlan flow within ns-3, and I have started on adding a couple of 802.11ad PHY into ns-3.
I have a reasonable grasp of 802.11ad but there are of course a few things I'll need to properly cover when the time comes such as the association beamforming training and medium contention within the announcement period. This stuff will come when I need to add it into ns-3.
I have begun my additions to ns-3 by starting with the channel and PHY layers with the addition of 2 out of 32 different modulation and coding scheme types, the Control PHY at 27 Mbps and a single carrier BPSK PHY at just over a Gbps. I am currently working on the addition of a TxVector object to be passed up and down the stack to allow easy attribute additions in the future.

26

Mar

2013

Over the last couple of weeks I have been writing sections in my background chapter on ns-3 and 802.11. I have detailed how ns-3 works, the objects involved and an overview of how the WiFi model works and is used. With 802.11 I have talked about details of the PHY and MAC layers.

In the next week I will be reviewing the material on 802.11ad.

12

Mar

2013

This week I have been reviewing a lot of material on 802.11 and the wifi model in ns-3 at a higher layer. I have captured traces of simulated and real 802.11 networks and have been analysing these. I am also comparing parts of these traces with relevant documentation to gain an understanding of how it all works. The next part of my work will be writing a number of pages on these reviewed topics to go into the thesis.

03

Mar

2013

This week I began my Masters under the supervision of Dr. Dean Armstrong at Virscient Limited and Dr. Richard Nelson. The purpose of my thesis is to develop a framework of simulation for IEEE 802.11ad using ns-3. 802.11ad is a new wireless standard for multi-Gbps throughput in the 60GHz spectrum. I will be extending ns-3 to support the new MAC and model physical and logical characteristics as well as designing a set of use cases for testing and showcasing the standard.

I have so far been reviewing material on ns-3 as well as learning a bit of Python and C++.

10

Dec

2012

Build an tested a couple of my second revision nodes and they work. Have also been investigating power consumption minimisation and fixing a atomicity issue with the wireless transceiver.

15

Oct

2012

Been flatout over the past couple of weeks working on assignments and my report. Just got another chapter to write and plenty of proof reading and additions to go. Haven't had any time to finish building the boards up and probably wont before the report is due.

26

Sep

2012

This week has just been a mix assignments and a test, although I have made progress of my report with nearly two chapters complete. The new boards have arrived so now it's just a matter of finding time for me to assemble them.