Wi-Fi 7 put to Test

Wi-Fi 7 comes with the promise of a lot of cool new features like 4096 QAM, 320 MHz , MLO , Preamble puncturing, 16x16 MIMO which are designed to improve overall throughput, efficiency and reliability. But do these features really work well in the real world? In this post Wi-Fi 7 put to test, we will try to explore all these features and put them to test . In today's post we are put 4K-QAM to test!!!

While 1024 QAM in WiFi6 allows encoding of 10 bits per symbol, 4K QAM allows for encoding of 12 bits per symbol which improves the PHY data rates by about 15%. But this comes at a cost as higher modulation rates need much better SNR which can only be achieved at very short range.

There is always a tradeoff between QAM and Distance and as the distance is increasing the QAM will get deprived.

So, to test 4k QAM I have used a TP-Link Wi-Fi 7 access point which is available for purchase in the market. As a client, I am using a be200 radio installed in my traffic generator called LANforge . I have configured the operating bandwidth in the AP as 160 MHz Now I have connected the client and started running the traffic and here are my findings in BE mode:

The throughput achieved is up to 2.4Gbps, I have seen the client is operating MCS 12 and 13 while running the traffic which comprehends the usage of 4096-QAM.

To understand the importance of 4096 QAM, I have connected the client in AX mode and have run the traffic.

I have noticed that the client is running the traffic at MCS 11, and the maximum throughput achieved in AX mode is 2.17Gbps.

So clearly, we can see that due to the client operating at MCS 12 and 13 there is nearly 300 Mbps of throughput improvement in Wi-Fi 7 when compared to Wi-Fi 6. So, in this way we can see that the 4096 QAM enhances the throughput performance.

But what about the trade-off between QAM vs distance?

To understand the usage of QAM with increase of distance, I have placed the Access Point and Traffic generator in 2 different chambers and connected them using RF cables and attenuators.

Now I have initiated a Rate vs Range test where client will run traffic with increase of distance at equal interval of time. Initially the client is connected to Access Point at -35 dBm RSSI, now we will try to increase the signal by 5 dBm after every 30 seconds and parallelly the client will try to run 5Gbps of UDP downstream traffic.

Here we can clearly see that with only 5dBm increase in attenuation, the PHY-rate got fluctuated resulting in the drop of throughput.

The MCS rates are constant up to?-50 dBm in AX mode and there is not drop. Whereas in BE mode the MCS got dropped even at -40 dBm which describes the significant tradeoff between the QAM and distance.

Here is a video where I have discussed about all the information regarding 4096-QAM and the Wireshark captures which are useful for validating the 4096-QAM:

I will come back again after some more feature-based experiments on Wi-Fi 7 and share my findings!!!

Happy testing!!!!!!

Attaching the pcap download link for reference: https://drive.google.com/file/d/1xQ79ZCnVdBgg2QjfS1vSWRQyt86W_Jh3/view?usp=sharing