WiFi: What are control response frames?

I have pasted some snippets from the standard which describe how rate control has to work for these special frames. This blog post is based on excerpts from section 9.7 of the 802.11 standard.

What are control response frames?
Following table shows all control frames, with the control response frames highlighted in bold:

Type description	Subtype value	Subtype description
01	Control	0000-0111	Reserved
01	Control	1000	Block Ack Request
01	Control	1001	Block Ack
01	Control	1010	PS-Poll
01	Control	1011	RTS
01	Control	1100	CTS
01	Control	1101	ACK
01	Control	1110	CF-end
01	Control	1111	CF-end + CF-ack

ACK or CTS or block-ack frames are referred to as control response frames by the WiFi standard. These are referred so because they are control frames sent in response to other frames.

How is rate selected for these frames?

Dynamic Load Balancing for WiFi

With WLANs and WiFi architecture moving more towards software than a "burnt in the silicon" approach, it is possible to have different software components running at different points in the network. 

Consider for example the following functions that need to be done in the typical transmit lifecycle of a packet received on the ethernet interface that is supposed to go out on a WiFi interface:

1. Ethernet receive handling
2. Basic ethernet classification and fowarding
3. Stripping of headers
4. Attaching LLC headers
5. Attaching WiFi headers
6. Queening frames for transmission
7. DMA'ing frames
8. Scheduling frames for transmission
9. Aggregation at different layers
10. Encryption

WINLAB Research: ORBIT Testbed & Related Work

This blog post is for archival of old research done at winlab.rutgers.edu


This project involved among other things, integrating ORBIT services for facilitating remote experimentation, network virtualization to improve testbed utilization, and developing schemes for better topology mapping using software approaches. Previous efforts also included a prototype for allowing integrated experimentation between the Planetlab (wired) and ORBIT (wireless) experimentation consoles. Our work on the ORBIT testbed was also featured recently among 10 emerging technologies on the MIT Technology Review. 

WiFi: AMSDU vs AMPDU: A Brief Tutorial on WiFi Aggregation Support

• WiFi MAC architecture supports aggregation at two layers. 
• The MAC service data  units (MSDUs) can be aggregated to form AMSDUs. 
• Each AMSDU serves as a single MAC protocol data unit (MPDU). 
• Another layer of aggregation is introduced when MPDUs can be packed together

WiFi Aggregation 

Wireless Channel Power Control

Our ideas for a hybrid approach for channel power control have been discussed here:

S. Ganu, G. Bhanage, P. Narasimhan, "System and Method for Computing Coverage Set and Resource Allocations in Wireless Networks", US Patent App. 13/563,500, 2014.

The key difference as noted in the application is that in some cases we propose using a combination of centralized and de-centralized channel power control i.e. the main channel allocation is done centrally and the local channel flips (based on radar etc) are done locally by the access point.

We propose doing a 2 phase channel allocation strategy:
1. Anchor channels: The baseline RF characteristics of a deployment rarely change i.e. the relative position of the infrastructure APs does not change, the other architecture of the building and basic coarse grained pathloss do not change over large time frames. We use this knowledge to come up with a coarse grained anchor channel assignment for each access point. This anchor channel will be a home channel based on the available

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