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AndyP88
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AC800S no carrier aggregation

Hi,
I have an AC800S with the latest firmware NTG9X40C_11.14.08.39 which is supposed to support cat 9 or cat 11 carrier aggregation. However it only ever connects to one band.

My iPhone 11Pro meanwhile can do carrier aggregation and is about 3 x faster on speed test connecting to the same server.

Please help fix this issue as I would like to use the AC800S modem to its full capability. My cell tower according to RFNSA has the following frequencies available:
4G
700MHz, 1800MHz, 2100MHz
4G+
2300MHz
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Mkrtich
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Re: ACS800 no carrier aggregation

Hi - may I ask why you think it is only connecting to one band all the time - have you Telenet accessed your AC800S to see it limited to one Channel and do you live along way away from the tower? Your comparisons with the iPhone Pro is somewhat unfair, its is a CAT 19 device, has 4x4 MIMO and a very fast Intel processer and capable of 5 Channel Aggregation (not sure if used in Australia or if carriers here have placed a limit on 3).

Your ACS800 S at CAT 11 firmware may have a 2x2 MIMO and connects to the cell tower in a real time dynamic environment and will use whatever band and channels are available at the time based on traffic load and your location. Your speed measurements - are they using the 5Ghz Wi-Fi or USB cable connection. If you have the time, get a cup of tea or coffee and have a read of this Whirlpool URL, it provides great insight to people's experiences with your topic - its two years worth and I stopped at end of a very long Page 1.

Telnet commands are listed there allowing you to see the actual channels being aggregated - PCC being the Primary and SCC1 and SCC2 being the additional ones. People's postings of their speed experiences for channel aggregation varied depending on the above stated conditions which define how your AC800S is connected at time of Telnet view. Some people changed their Settings from Auto to 4G All or specified a preference but found that did not set in all circumstances and went back to Auto. 

Examples : 1 B3 + 2 x B40, 3 x B40, 1 B3 + 1B7 +1 B28. [Add the Rx Chain figures for Download and the singe Tx figure is your Upload] 

B3 - 4G  1800Mhz (15 Mhz width)

B40 - 4G 2300 Mhz (20 Mhz width)

B7 - 4G 2600 Mhz

B28 - 4G 700 Mhz (10Mhz)

https://forums.whirlpool.net.au/archive/2663224

https://au.pcmag.com/apple-iphone-xs/63642/exclusive-on-lte-performance-iphone-11-pro-ties-iphone-xs

AndyP88
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Re: ACS800 no carrier aggregation

Thanks for you response. 

By "Dialing" *3001#12345#* into my iphone I can view the Carrier Aggregation Status under "CA Status" and I noted I am connected to:

B40 2300Mhz TD 20Mhz bandwidth (Carrier 0 SCC_STATE_ACTIVATED) 

B40 2300Mhz TD 20Mhz bandwidth (Carrier 2 SCC_STATE_ACTIVATED) 

B1 2100Mhz FDD 15Mhz bandwidth (Carrier 1 SCC_STATE_CONFIGURED_DEACTIVATED which i presume means it's not connected by settings from Optus, not sure if it gets activated when it's not busy or I need more bandwidth)

Another page on that shows "Server Cell Measure" I presume these are the two connected carriers

RSRP0:-90 RSRQ0: -14 SINR0:25

RSRP1:-95 RSRQ1:-14 SINR1:25

On my iphone when i do speedtest to the same server as my modem i get Download 345Mbps and Upload 41.8Mbps. While my modem gets 140Mbps and 17Mbps to the same server (i did this via USB tethering on laptop). I noticed my modem connected to different frequencies than my iphone even though the phone and modem are in the same location. 

I was looking at the netgear app which only showed one band (B28 700Mhz). I'm located 205m from the cell tower.

I have now completed a Telnet and you are correct it is connecting on

B28 700Mhz FDD 10Mhz bandwidth

B40 2300Mhz TD 20Mhz bandwidth

B40 2300Mhz TD 20Mhz bandwidth

!GSTATUS:
Current Time: 2367 Mode: ONLINE
System mode: LTE PS state: Attached
EMM state: Registered Normal Service
RRC state: RRC Connected
IMS reg state: No Srv

PCC:
LTE band: B28
LTE bw: 10 MHz
LTE Rx chan: 9260
LTE Tx chan: 27260
RSSI (dBm): -42.1
RSRP (dBm): -72.4
RSRQ (dB): -12.7
RSSNR (dB): 15
Tx Power (dBm):
LTE Cell ID: 23415858
Physical Cell ID: 164
TAC: 57504

SCC1:
LTE band: B40
LTE bw: 20 MHz
LTE Rx chan: 38968
RSSI (dBm): -60.6
RSRP (dBm): -93.5
RSRQ (dB): -10.2
Physical Cell ID: 232

SCC2:
LTE band: B40
LTE bw: 20 MHz
LTE Rx chan: 38770
RSSI (dBm): -63.0
RSRP (dBm): -95.2
RSRQ (dB): -9.0
Physical Cell ID: 232

Mkrtich
Valued Contributor
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Re: ACS800 no carrier aggregation

Thank you for your feedback and sharing your investigation outcomes with the forum. I am not conversant with 4G LTE technologies to any great depth, but here are my observations.

1. Channel Aggregation is one major element of the speed circuit. There are other factors that also contribute to higher speeds.  The iPhone 11 Pro is a very highly rated beast and may explain why it sits at the top of a price curve. Its modem's features enable higher throughput- 4x4 MIMO Antennae capability (may not be fully used by Optus) , the Intel LTE Modem XMM7560 capable supporting 3GPP Release 13 - 1Gbps Download (CAT16) and 150 Mbps Upload (CAT13) and is LAA compliant. This means it is  also capable of using any available unlicensed 5Ghz Wi-Fi to increase its throughput subject to carrier support. This may become relevant when the full 5G NR standard is released in the next three to five year time frame? It also does 256 QAM coding (not sure of the  AC800S here, could be 64 QAM given its age) and would also have other enhanced coding techniques to support higher speeds. Very similar to Wi-Fi concepts.  How the device uses its capability is governed by what the carrier allows, what the  local tower and its individual multiple Cells are capable of at time of your connection. 

2. The AC800S statistics are very comprehensive down to the Cell Level on the Tower (Server), whereas the Apple shows less information. Unlike Telstra, Optus has managed to do Channel Aggregation using FDD for the Primary Channel and TDD for the one or two extension Channels*. Other carriers may be limited to use just one type - FDD or TDD. The iPhone seems to  list the Channels showing three SCC extension Channels with no PCC displayed -  don't know if your Field Test Mode occupies the PCC for the test?  

* Not clear on the Apple iPhone as it is showing Carrier 0 as SCC - the prime? 

3. The AC800S PCC 700 Mhz (slower speed, but longer coverage) signal statistics verify it is the strongest channel by far, the lesser figures the better and a 3dBm difference usually means a significant improvement, your figures you have an approx 18dBm difference. Your SCC 2300 Mhz ( fast speed, less coverage) channel/s signal strengths are significantly worse and this is expected given they are at a higher frequency , but they are operating at much higher speeds than the 700 Mhz channel. I am assuming the SNR figure listed is the difference between Signal strength and Noise - once again the 700 Mhz is providing a clearer signal (+ SNR) than the 2300 Mhz signal (-SNR). All as expected.

4. The Apple iPhone statistics is not so easy to  understand for me. It has the worse signal strength by far and the SNR figures are presented in an unfamiliar to me SINR format. You are still in the range of -91 dBm to -105 dBm for a good signal with fast data speeds.  The lower signal indicators may be influenced by you being too close to the tower with its multiple cells or adjoining cells beamforming outwards rather than omni spherical pattern -  don't know enough about the broadcast pattern used on LTE frequencies.     

5. Its been an interesting learning exercise for me and hope this may help explain some of what may be going on. Some people have found adding the Netgear cradle to the AC800S to increase their data speeds in a handy manner and also provide the ability to connect Ethernet devices to to be useful. I don't think it is an Optus supported product.   

https://www.intel.com/content/www/us/en/products/docs/wireless-products/mobile-communications/xmm-75...

AndyP88
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Re: ACS800 no carrier aggregation

Thanks for the info you’ve prompted me to read some more into all this.

So since discovering the speed discrepancies between iPhone 11 Pro(300-400Mbps download/20-50Mbps Upload and 15-20ms ping) vs AC800S(50-150Mbps download/10-50Mbps Upload) I’ve done some more reading.

The main things that I’ve discovered impacts LTE speeds between these 2 devices:
- LTE category (max download and max upload speeds based on carrier aggregation capabilities and QAM)
- MIMO - Multiple In Multiple Out (basically the number of antennas at the tower and antennas at your device - cell towers have to be configured with MIMO support)
- QAM - Quadrature amplitude modulation (modulation of data to get better efficiency)

Both iPhone and AC800S are limited to 3 carrier frequencies by Optus so the LTE category capability although different doesn’t appear to impact it. Router is cat 9 and iPhone is Cat16 download and Cat 13 upload but optus doesn’t appear to fully support all that capability.

iPhone has 4x4 MIMO whilst router has 2x2 MIMO (2 antennas vs 4 antennas). More antennas also seem to increase the SNR (ie better signal which allows more efficient QAM).

Next the QAM will probably impact it. iPhone is 256QAM, AC800S is 64QAM. QAM seems to automatically degrade to the lower modulation based on Signal To Noise Ratio(SNR):
16QAM 10.5
64QAM 18.5
256QAM 24
1024QAM 28

The next steps will be to figure out do I want to go for:
- A new LTE Router with improved features (4x4 MIMO with QAM)
- Test out whether I can force the router to use B1 2100Mhz FDD which should have less devices connected because the signal will be weak if your not near the tower.
- Consider external antennas with the Cradle (seems the cradle is discontinued by Netgear). I might be able to convince the auto detection by selecting an antenna which targets the upper frequencies and pointing it at the cell tower from my roof)
- Or just wait for 5G and then upgrade router...

Also those of you who want to Telnet to AC800S. I found these steps worked for me:
- had to download Putty for Windows (command prompt would add extra characters when tying commands)
- Connect the AC800S via USB to laptop (Telnet doesn’t work over wifi - maybe a security feature)
- IP to connect to 192.168.1.1 Port 5510
- Command to view status “AT!GSTATUS?”
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Mkrtich
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Re: ACS800 no carrier aggregation

Great summary. I am not sure, but  I think it would be hard to find a 5G or 4GLTE modem/router today that supports 1024 QAM on Downlink and I am unaware if Optus deploy that level QAM in the mobile network.

The other criteria for QAM Modulation is its variable coding mechanism and accuracy used for throughput. In Wi-Fi there are different levels of QAM that the modem deploys subject to the signal and noise environment it encounters. I would think the same would apply to 4G LTE. The 256 QAM may start out at a 5/6 Code (83%) but drop down to a 3/4 code (75%) throughput or even slide down to 64QAM or 16QAM if circumstances warrant with 2/3 and 1/2 coding respectively. The shortened name assigned to a modem's capability for both of these factors is known as its MCS Index e.g. the two higher MCS Indexes, 8 , is [256+3/4 coding] combo and a 9 is (256+5/6 coding] combo. This is why some people have miserable experience with their Wi-FI network speeds. 

In Wi-Fi, only very recently released high end priced residential modems (generally with non-standard propriety coding that may require use of their adaptors)  offer 1024 QAM. It is rarely used as most people's devices don't have Wi-Fi adaptors to support that level high level of QAM. You can determine the 4G LTE or 5G modem's capabilities by looking at its modem chip's technical specifications and then check if the carrier supports that in the network. 

The Optus Nokia FastMile 5G uses 256 QAM on Downlink and 64QAM on Uplink and a 2x2 MIMO antennae. Huawei B818-263 is a CAT 19 4G LTE modem with 256 QAM with 4x4 MIMO antennae, some variants overseas support 8x8 MIMO. The HTC 5G Hub Hotspot uses Qualcomm's Snapdragon X50 5G modem; both FDD and TDD variants support 2x2 MIMO and 4x4 MIMO for their various future configurations, yet to be deployed, 5G frequencies operations in mind whilst accommodating current 4G LTE MIMO arrangements which are unknown to me. 

The other factor which doesn't seem to be listed in 4G LTE specifications is the number of spatial streams (SS). In Wi-Fi, the MIMO is represented as Single User-MIMO or Multi User-MIMO and usually depicted as 4x4: 4 (SS) meaning four antennae and 4 spatial streams capable of being bonded;  you may also see 3x3:3, 3x3:2 or 2x2:2. If the Wi-Fi modem or the 4GLTE Cell is utilising its pre-assigned available streams to meet its dynamic demand, your device may or may not be given its spatial stream capacity at time of connection. Another factor which contributes to unexpected speed results that do not match the claimed maximum speeds on brochures. 

I think the AC800S is a good product for its intended use - its a portable mobile hotspot which can be enhanced with a cradle or even external antennae and operate faster in a different external location. Its designed for portability without hassle and does not depend on a power point on the go. Your speeds on it are enviable for most NBN 50/20 users and they will vary due to the nature of 4G LTE; higher level modems are also not immune from the unexpected lower performance speeds. The Apple iPhone is also a great Personal Hotspot for people who have a generous data allowance in their plan. We are at the beginning of the phase of seeing new products entering the 4G and pre-real 5G NR market, so I would expect to see continuing enhancements or new products to come our way over the next year or so.   

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AndrewC1
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Re: ACS800 no carrier aggregation

The AC800S with a Telstra SIM in it speed along at around 90-94Mbps peek on speed test. Unfortunately the tower near me has a stuffed 2300Mhz and as such sucks. I bought a Telstea data SIM on special at woolies for testing two weeks ago.

I have moved to a B818 and have locked it to 2100Mhz and get between 8 and 12 Mbps during the day (peak is around the 12Mbps).

Hope this is of some use.

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Mkrtich
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Re: ACS800 no carrier aggregation

Thanks for sharing your experiences. Did the B818 use an Optus SIM or the Telstra SIM and was there a particular reason you locked it into the 2100 Mhz frequency?  This link shows which frequencies are used by carriers - not sure if updated, but according to it, Telstra only has a handful of 2100 Mhz sites which may contribute to an unexpected result if you had used it.   https://whirlpool.net.au/wiki/mobile_phone_frequencies

When the modem is set to Auto frequency selection, it should select an optimum frequency at time of connection and may alter if circumstances change. I would have expected the 700 and 1800 Mhz frequencies to provide a better outcome - the very low results imply a weak signal or overcrowded cell.  If you are not aware of it already, this link shows you where you suburb's cell towers are located and what frequencies they are broadcasting. https://www.rfnsa.com.au/?first=1

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AndrewC1
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Re: ACS800 no carrier aggregation

I have used both SIMs in the B818 and the Telstra SIM is allot quicker due to the Optus tower neareat me having a stuffed 2300Mhz band. I unlock all the bands when I used the Telstra SIM.

 

Both the B818 and AC800S carrier aggregation DO NOT work correctly if there is a tower problem with the 2300Mhz band and possibly other bands, but the tower near me has had the issue for since 4-April-2020 with no fix scheduled (aka Optus have no timeline as to when it is going to be fixed two weeks ago and it's still showing as faulty). From my reading it looks like CA kicks in on downloads only and looks like it only kicks in when the current band gets saturated (aka hits the download limit or close to it, but I could be wrong).

I have spent at least 24 hours on this with Optus and they did not even know that the B818 or other modems they sold could be band locked/unlocked and I asked if they could escalate it to get an answer. I got better help at Whirlpool on modems that with Optus.

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