Technical details of congestion on FDD and TDD LTE

[newyorker]

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?

 

[ImmerStark]

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.

[WiWavelength]

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

[JosefTor]

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?

[WiWavelength]

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

Both.

 

AJ