Does iPhone 16 support the optional 4096-QAM Wi-Fi 7 feature?

iPhone 16

Apple has just published a new and very useful Wi-Fi specification document which answers this question.

Note the Maximum MCS index column

What is 4096-QAM?

It is the latest modulation technique that allows the access point and Wi-Fi client to send even more data over the air than ever before. Effectively, it adds 2 new MCS indexes 12 and 13 and unlocks faster data rates.

4096-QAM MCS indexes, credit to http://mcsindex.net

Achieving it is challenging as it requires very high Signal to Noise Radio (SNR) – that’s very strong signal and low noise. So in practical terms, it is only used quite rarely.

For context, with another client device using Intel BE200 Wi-Fi 7 adapter, I hit MCS 12 with SNR about 60-62 dB. In other words, if my noise floor was -95 dBm, my signal would have to be about -35 dBm.

Does iPhone 16 support it then?

According to the above spec sheet, the maximum Extremely High Throughput (EHT) the iPhone can achieve is MCS 11. 4096-QAM only uses MCS indexes 12 and 13. Check the mcsindex.net site.

So, the answer is no, it doesn’t.

Is it a dealbreaker?

From data rate perspective, even without 4096-QAM, and using 160 MHz wide channel, we are talking 2000+Mbps! Obviously depending on how far you are from the access point.

So I personally can’t complain. I value access to the clean 6 GHz spectrum, low latency and low retransmissions rate over maximum throughput.

My WAN link speed of 900 Mbps is my personal bottleneck and I usually don’t transfer huge amounts of data from the phone.

High Tx (transmit) and Rx (receive) rates

On a laptop, I can imagine 4096-QAM to deliver much more value when it comes to performing backups for moving very large software image or video files. Having said that, don’t forget that there is 2.5, 5 or 10 Gigabit Ethernet for that.

Does iPhone 16 support Wi-Fi 7 Multi-Link Operation (MLO)?

iPhone 16 supports tri-band Wi-Fi 7 and Multi-Link Operation (MLO). More specifically, the Enhanced Multilink Single‐Radio (EMLSR) mode. The client connects using 2 different Wi-Fi bands, only actively uses 1 of them and listens on both bands simultaneously. Let’s enable it on an access point and verify that it works.

Multi-Link Operation

We have a 320 MHz channel configured on the 6 GHz radio. This is for experimental purposes only. Please use narrower channel in production to avoid adjacent channel interference with other 6 GHz access points.

Wi-Fi 7 network with MLO enabled

From client perspective, the iPhone connects using 160 MHz channel width as that is the maximum it supports.

The tri-band SSID is announced in 2.4 GHz, 5 GHz and 6 GHz bands. It is up to the client device to choose the preferred band. MLO-capable Wi-Fi 7 clients can also enable the MLO feature.

Although iPhone 16 supports MLO, the phone itself doesn’t indicate if MLO is active or not. So our only option is to monitor it from the access point’s side. This is a consumer access point and it doesn’t provide a huge amount of detail. I am hoping to retest this with a proper enterprise-grade AP when I can.

Single band at a time

From the Association Request sent by the iPhone to the access point, we can see that it advertises support for only one band at a time.

⏬ Feel free to download the Association Request Wi-Fi frame and dig deeper.

Single band MLD support

6 GHz and 2.4 GHz EMLSR MLO mode

With the default settings of the TP-Link Deco BE85 Wi-Fi 7 access point in place, the iPhone establishes MLO using 2.4 GHz and 6 GHz. It actively uses 6 GHz. 2.4 GHz is there for backup purposes.

TP-Link Deco app shows MLO using 2.4 GHz and 6 GHz

The iPhone uses its 160 MHz wide channel capability and actively pushes all data using the 6 GHz channel 69 as I am trying to demonstrate below using Oscium WiPry Clarity spectrum analyser. Check the “waterfall diagram” that shows the top 160 MHz of the 320 MHz channel being busy processing the data transmission.

MLO in action with iPhone primarily using 6 GHz band

The 2.4 GHz link just sits there in the background, unused. Using the same method, I verified that there is no spectrum utilisation whatsoever on the 2.4 GHz channel.

5 GHz and 2.4 GHz EMLSR MLO mode

When we change Preferred Wi-Fi Band setting to 5 GHz, the iPhone establishes 5 GHz active MLO link and 2.4 GHz as backup.

TP-Link Deco app

6 GHz and 5 GHz EMLSR MLO mode

Now, how do we force MLO using the two modern bands? For the purposes of the demo, I simply disable 2.4 GHz radio on the access point.

Disable 2.4 GHz using TP-Link Deco app

The phone establishes 6 GHz active data connection and uses the 5 GHz band as a backup. How can I be so sure? I watched the spectrum and generated nearly 900 Mbps of data over the wireless link. While the 6 GHz channel shows high utilisation, the 5 GHz channel shows no signs of use.

TP-Link Deco app shows 6 GHz and 5 GHz MLO

On the iPhone, we see active channels 69 in the 6 GHz band. That matches what I’ve just seen using the spectrum analyser.

Active 6 GHz channel 69 using max iPhone 16 channel width 160 MHz

How to trigger MLO band change?

Now, I connect the iPhone using 5 GHz channel. I am going to saturate the channel with other client’s traffic. My hope is that high channel utilisation makes the iPhone stop using the 5 GHz channel and switch to the backup 2.4 GHz channel.

And the result? It correctly detected and reported high channel utilisation, but the MLO band change did not happen.

High channel utilisation

So channel utilisation on its own did not do the trick for me. Perhaps the algorithm penalises and tries to avoid the 2.4 GHz band which is typically in a much worse condition than 5 GHz? Or high channel utilisation must persist for a longer period of time? Time will tell.

What Wi-Fi 7 chip does iPhone 16 use?

As we have learned previously, iPhone 16 supports channel width up to 160 MHz and indeed supports all three 2.4 GHz, 5 GHz and 6 GHz Wi-Fi bands.

iPhone 16

What chipset does it use? To find out we are going to enable Personal Hotspot on the iPhone and see what information we can get from the information elements it broadcasts in its beacons.

As we can see here, iPhone 16 uses Broadcom Wi-Fi 7 chip. That’s about the level of detail we can capture from the beacon frames it sends.

Broadcom chip

Continue reading

Does the iPhone 16 support Multi-Link Operation? Check this blog post.

Does iPhone 16 support 320 MHz channel width in the 6 GHz Wi-Fi band?

All iPhone 16 models support tri-band Wi-Fi 7 as you might have seen here. But what is the maximum channel width they support in the 6 GHz band?

iPhone 16

Although my Wi-Fi 7 access point uses 320 MHz wide channel, the maximum 6 GHz channel width iPhone 16 supports is 160 MHz.

AP using 320 MHz wide channel

Here is the client view of the world.

iOS Wi-Fi Diagnostics profile provides extra information

Spectrum view

I am using Oscium WiPry Clarity 6 GHz spectrum analyser to see the spectrum. When we run a WAN speed tool Speedtest.net (it is not designed to be a Wi-Fi test tool) to generate some traffic here and see how it utilizes the 160 MHz channel.

Outside of that, I also checked the 2.4 GHz channel. There was no activity there. So that proves that only one of the 2 bands involved in MLO is active at a time.

Only the 6 GHz channel is active during data transfer, 2.4 GHz isn’t actively used

Updated: Apple’s iPhone 16 Wi-Fi specification

New documentation is now available directly from Apple. Note that 160 MHz is the maximum channel width for all models.

iPhone 16 Wi-Fi specification published by Apple

You normally won’t use 320 MHz wide channel anyway in Europe

Having said that, at least in Europe, we only have one 320 MHz wide channel available. So by the time you add a second access point you will have to downgrade to 160 MHz channels or narrower. That is to prevent the 2 APs from stepping on each other’s toes and causing adjacent channel interference. No support for 320 MHz channel width on the iPhone is not really a problem.

If you were considering using 320 MHz channels, or if your vendor uses that as a factory default setting, please be a good citizen and don’t.

Does iPhone 16 support 6 GHz Wi-Fi 7 band?

All iPhone 16 models now support Wi-Fi 7 and come with 2×2 MIMO 2-Spatial Stream radio configuration. But Wi-Fi 7 doesn’t make support of 6 GHz band mandatory. So technically there could be Wi-Fi 7 clients that only support 2.4 GHz and 5 GHz.

Do iPhones 16 support all three 2.4 GHz, 5 GHz and 6 GHz Wi-Fi bands?

I tested a standard non-Pro iPhone 16 model.

It indeed supports all three Wi-Fi bands. Here is a proof of iPhone 16 connected to a Wi-Fi 7 access point using 6 GHz channel 69.

iPhone 16 connected using the 6 GHz Wi-Fi band

Using the My Wi-Fi Apple Shortcut we can look into another level of detail. In this case the iPhone is using the 802.11be Wi-Fi 7 standard to communicate with the access point.

iPhone 16 using Wi-Fi 7 802.11be standard

Association Request

As the iPhone associates to the AP, it announces no support for 320 MHz channel width.

⏬ Feel free to download the Association Request Wi-Fi frame and dig deeper.

No support for 320 MHz channel in Association Request

Continue reading

What Wi-Fi 7 chip does it use? Find out here.

Does it support 320 MHz channel width in the 6 GHz band? Let’s find out.

Does it support Multi-Link Operation? Yes, it does!

Direct 20 Gbps connection between Mac and Windows 11 machine with no Ethernet adapters

Problem statement

Here is the challenge. We have a MacBook Pro M2 and an Intel NUC 12th generation PC running Windows 11. We want to transfer a significant amount of data between the two and potentially sync content of 2 directories. The Mac has no Ethernet adapter.

Solution

Both machines support Thunderbolt 4 and USB4. I happen to have a 0.5 m (1.6 ft) Thunderbolt 4 cable in my tools bag. We connect the two machines back to back. They establish USB4 peer to peer 20/20 Gbps connection, and automatically assign locally significant IP addresses from the 169.254.0.0/16 APIPA range.

For the record, I am using the Thunderbolt 4 cable shipped with my trusty OWC 10 Gigabit Ethernet Thunderbolt adapter.

Direct MacBook to Intel NUC USB4 20/20 Gbps connection

The MacBook side

Let’s start with the Mac. Head over to System Settings and Network. Select the Thunderbolt Bridge adapter and explore its config.

Thunderbolt bridge interface and IP address

As far as I can tell, the machines have decided to use USB4. From what Windows network manager is telling us, they negotiated 20/20 Gbps link speed. I expected 40 Gbps but I think I set a wrong expectation in my head. 20 Gbps up and 20 Gbps down full duplex makes up 40 Gbps.

Windows PC on the other end of the Thunderbolt link

A quick iperf3 test gives us amazing throughput of 16.4 Gbps of TCP traffic from the Mac client to PC server. That’s fast!

16.4 Gbps of TCP traffic from Mac to PC

By default macOS uses standard MTU size of 1500 Bytes. This is important hold that thought.

Standard MTU

In the downstream direction, that is from Windows PC towards the Mac, we “only” get 5.3 Gbps. Windows claims 20/20 Gbps link speed, so what’s wrong?

Limited 5.3 Gbps TCP throughput from PC to Mac

Yes, we need to bump MTU (Maximum Transmission Unit) size to the maximum value of 9000 Bytes on my Mac. Apparently, Windows defaults to 62000 Bytes MTU on this peer to peer link type, and there is no UI option to change it. But that’s fine for now.

Enable Jumbo frame support on Mac

Let’s retest upload speed. Now we are talking. That’s 16.4 Gbps TCP from Mac to PC and 12.8 Gbps from PC to Mac. I am starting the file transfer.

12.8 Gbps TCP from PC to Mac with Jumbo frames enabled

We are not done yet.

Intel NUC and the Windows part

Windows sees this link as a peer to peer USB4 connection.

Connection status

The two machines negotiated a 20/20 Gbps link. Windows uses 62000 Bytes MTU by default with no obvious UI option to change it. Mac uses 9000 Bytes. MTU mismatch is bad and we should fix that.

20/20 Gbps USB4 P2P link
Adapter settings don’t offer MTU adjustment in the UI

Let’s deal with the MTU, and set it to 9000 Bytes on Windows. Same as the Mac.

Set MTU to 9000 Bytes on Windows 11 for this adapter

With matching MTU on both sides of the pipe, we get 15.1 Gbps TCP throughput from Mac to PC, and 13.6 Gbps from PC to Mac. Slightly more symmetrical in both directions.

Mac to PC
PC to Mac

Summary

I knew Thunderbolt 4 peer to peer connection was possible between 2 Macs but I’ve never tried connecting a Mac to a PC. It works.

Use a Thunderbolt 4 cable, not just a regular “USB-C to USB-C” cable. If there is a Mac involved, increase macOS MTU size to Jumbo 9000 Bytes and match MTU setting on both machines.

The outcome is a peer to peer 20/20 Gbps USB4 link with TCP throughput around 15 Gbps in either direction.

Apple iOS Shortcut: Install Wi-Fi diagnostics profile to your iPhone the easy way

Apple developed a diagnostics profile that allows you to monitor and troubleshoot Wi-Fi connectivity. Unfortunately, it is only available for 7 days after installation. After that, it get automatically removed. If you are a Wi-Fi professional, that means that you need to reinstall it every few days. Yes, it always disables when you are on site and need it the most :)

Manual installation of the profile – the hard way

Normally, I would google something along the lines of “Apple Wi-Fi diagnostics profile”, eventually I find the right link, log in, search for the iOS Wi-Fi profile on the Apple Developer website, download the profile, go to Settings > General > Profiles section, and I install it from there.

Wi-Fi diagnostics profile for iOS devices

What if there was a little tool that did most of the above for you?

The easy way

I put together a quick “Wi-Fi Profile” Apple Shortcut that removes some of these steps. Install the shortcut on your phone and it will guide you through the diagnostics profile installation every time you need it. It downloads the profile to your iPhone, lets you approve the installation and voilà, you open Wi-Fi settings and get RSSI measurements, channel details, BSSID and other useful info.

How to add the Shortcut to your phone

Download the latest version from my GitHub and follow the video instructions. Save it your home screen and execute it whenever you want to reenable Wi-Fi diagnostics.

See the shortcut in action

More shortcuts, anyone?

I wrote few other Shortcuts. Perhaps you are connected to a someone’s guest network, and would like to see who their access point vendor is? Your iPhone can tell you.

Or you use 2 iPhones and want to get a reminder when your secondary/test phone’s battery drops below 10%?

Apple iOS Shortcut: Remind me to charge my secondary iPhone

Let me give you one more reason why you should explore the Shortcuts framework on your iOS or macOS device.

Remind me to charge my test phone

I mainly use my primary iPhone, but for testing I use an older iPhone running iOS Beta. Up until now, I struggled to keep the test phone charged. Typically I would pull it out of the bag and … you know the rest of this story, right?

I put together this quick but very useful shortcut. Whenever charge level drops below 10 %, the secondary phone will automatically send me an iMessage with a reminder. That’s it. Simple. Useful.

Recharge reminder automatically sent to me via iMessage from the secondary device

How does it work

Simply create a new Shortcut on the secondary iOS device, using the Shortcuts app. Select Send Message action and enter your iMessage details.

Now, in the Automation section, configure the trigger that executes this action. Set it to run whenever battery level drops below 10 %.

Then hit Done.