Frame Aggregation for NQoS Data?

Varun Reddy

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Oct 13, 2017, 12:54:09 PM10/13/17

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I am working on the development of the PCF module in Wifi for ns-3. I have a doubt regarding the working of the PCF.

Is Frame aggregation defined only for QoS Data? Looking through the current implementation in HT and VHT Physical layers in ns-3, it seems so. However, PCF is not used for QoS data, so does that mean frame aggregation cannot be employed in PCF?

Thanks,
Varun

Rediet

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Oct 18, 2017, 5:41:56 AM10/18/17

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Hi Varun,

Yes, aggregation is only possible with QoS data, since aggregation (both A-MSDU and A-MPDU) relies on information available in QoS Control field (e.g. TID, ACK policy, etc.).

PCF was defined before 11e introduced QoS. HCCA/HCF was introduced to improve PCF and extend it for QoS. So if you need aggregation and a centralized scheme, better go for HCF.

Rediet

Varun Reddy

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Oct 21, 2017, 4:50:09 PM10/21/17

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Thank you for your clarification, Rediet. Just another question - Is it possible to send Non-QoS data over 802.11n/ac? I understand that MAC layer throughput enhancements, such as frame aggregation, were introduced via QoS control for these newer 802.11 protocols, but does that mean non-QoS data can't be sent?

Thanks,
Varun

Rediet

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Oct 30, 2017, 9:20:58 AM10/30/17

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Hi Varun,

A 11n/ac STA is by definition a QoS STA. However a QoS STA has to be able to communicate with non-QoS STAs so it can also send such data, if need be. It thus depends on the environment.