Jump to content

Technical details of congestion on FDD and TDD LTE


newyorker

Recommended Posts

What actually happens technically when there is congestion on FDD and TDD and what happens to users data and speeds. What I'm looking for is tech details not personal anecdotes. Anyone have any links?

 

  • Like 2
Link to comment
Share on other sites

As the number of users on the system increases the number of sub carriers that can be allocated to each one is reduced. Generally this results in decreased throughput but maintains good latency since each user still has a dedicated(albeit low bandwidth) data path.

Link to comment
Share on other sites

As the number of users on the system increases the number of sub carriers that can be allocated to each one is reduced. Generally this results in decreased throughput but maintains good latency since each user still has a dedicated(albeit low bandwidth) data path.

 

Actually, the issue is not so much subcarriers as it is time slots.  The number of subcarriers that can be allocated to each user can never drop below 12 because that is one Resource Block.  A 5 MHz FDD carrier, for example, then has 25 RBs.  If greater than 25 users are present in a sector, they share the 25 RBs via alternating time slots.  And to a degree, that can increase latency.

 

AJ

  • Like 4
Link to comment
Share on other sites

if greater than 25 users are present in a sector, they share the 25 RBs via alternating time slots. And to a degree, that can increase latency.

Stupid question but is this 25 users in an area actively using data or just present and connected to the tower?

Link to comment
Share on other sites

Stupid question but is this 25 users in an area actively using data or just present and connected to the tower?

Both.

 

AJ

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • large.unreadcontent.png.6ef00db54e758d06

  • gallery_1_23_9202.png

  • Posts

    • The S21U was very spotty with connecting to 6E. It would only see it on a router reboot. I thought it was more the router than the S21U, however my laptop would solidly connect to the 6E network, so it must have been the S21U. Since I'm on WiFi7 with the S24U, I haven't kept track of it. I will flip over and check it out later. 
    • Wi-fi 6e missing (6 GHz on one of two ultras). Perhaps coming from an app?  Wifi analyzer can see the 6ghz, just can't see them to connect.  May try wifi reset, although communications reset could have been the source of this problem.  Others have reported it, so not an isolated issue. Edit: Fixed: Rebooted into safe mode. Wifi 6e worked. Normal boot back. No wifi 6e in available nerworks.  Unistalled Asus Router app. Checked for Wifi 6e being visible in wifi available networks. Nothing. Deleted Netgear Genie app. Then saw networks. of mine I had not connected to in wifi available networks. Forgot the desired 2.4&5&6 SSID that did not show 6E. Connected to it again. 6e now works.
    • I noticed today while I was out and about in Louisville that b30 has been widened back to 10x10. They reduced it to 5x5 back in Sept 2018 presumably due to satellite radio interference. Not sure how long ago the change happened but it couldn't have been too terribly long ago. I noticed the different earfcn in the neighbor list, I don't usually see b30 as pcc much but I wonder if that will change now. I locked my phone to b30 only on my drive home from work and noticed the new(old?) earfcn on every site, so it wasn't just a 1 or 2 site fluke. It also looks like they've been doing some fiber or other cabling work around the b2/b46 small cell nodes, I wonder if they are about to start adding c-band radios to those. 
    • Should trade it for some low-band there or elsewhere. AT&T dominates lowband.    
    • I checked existing spectrum holdings and selling 5x5 PCS to each of VZW and AT&T in Kauai would get them to 20x20 apiece there, which should make them happy. In Maui it makes more sense to sell 5x5 each of PCS and AWS to get VZW 20x20 AWS and AT&T 15x15 PCS. I figure it would be a sale rather than a swap, as neither of the other two have spectrum T-Mobile would want that's high-frequency enough to avoid the spectrum screen. Honestly, T-Mobile is strong enough in Hawaii from a capacity perspective that cutting down PCS/AWS holdings won't hurt, particularly in exchange for finally unlocking 2.5 (though in Maui I saw 140 MHz n41 regularly in September if I remember correctly).
  • Recently Browsing

    • No registered users viewing this page.
×
×
  • Create New...