Hi all,
I would like to know how many users can be concurrently active in a LTE cell.
I know it depends on several factors (bandwidth, hardware…). Is there also a vendor dependency on this value?
So, what would be the maximum number of concurrent (simultaneous) users - practical and theoretical value - that we can have, considering the main possible scenarios/factors?
Thanks in advance.
Adalberto.
Hello @adalbertotelecom
You are right, there is a lot of variables that affects the number of users. It will depend on the vendor implementation, memory and processing allocated, numbers of active bearers, etc.
The maximum number of users is a function of available resource blocks, but if we consider schedule for transmission, the number of active users in RRC connected state is higher.
A practical number most engineers use is about 100 users per cell.
BR,
Carlos
we know as user number increases as user speed decreases
but there is limitation in hardware resources like CE , power , and other resources
in 3G DO for example the first shortage can you face is CE at almost 50 user\cell
if vendor increases number of CE we will face the second shortage in MAC at 110 user\cell
but in LTE we don’t know which kind of resources is the first shortage
How many users can a cell carry without congestion?
I think we can more be more specific in here as this topic has many factors to consider.
For instance, in LTE, the number is limited by licensed RRC Connected Users.
I mean on both 3G and LTE. Some reference values.
Well, in 3G, practically speaking, you get HSDPA or HSUPA users congestion when the cell goes beyond the threshold for these measurements (in Huawei, relevant thresholds can be set through UCELLCAC). But honestly I am not what is the exact threshold of users that could cause other congestions (e.g. DL PWR)
Maybe someone could step in and enlighten us on this. 
For Nokia I think 300 RRC per cell. The 301 will be rejected.
Thanks. And for 3G, where RSSI is going high because of traffic cell is carrying?
In 3G High Traffic in UL generates high RSSI which shrinks the cell range.
So instead of 2 km it will be 800 meters (example).
UE from more than 800 m will be at max tx power and cannot transmit data anymore.
Perfect, understood. Thanks!
Scheduler is used to assign resource blocks (RBs) to all the users according to the traffic demand.
If we have BW 10 MHz then total RBs are 50.
These 50 resources available every TTI (1 ms).
The 50 resource blocks are available every millisecond. If the eNB has data for 100 UEs, then it will take at least 2 ms to serve all of them, since at most 50 can be scheduled in any millisecond.
eNB can serve up to 100 UEs simultaneously in each TTI (assuming 1 RB/UE criteria).
Moreover, in actual traffic conditions, all UEs are not always in active state, but quite a few are in Idle state and that also helps eNB to manage active UEs efficiently.
Every ms (subframe), the RBs are allocated to one or more of the active users; two users will not use the same RBs in that subframe. In the next subframe, all of the RBs are reallocated to the users as needed; there is no guarantee that the user will receive the same RBs as before (or even any blocks at all).
I thought that it can go beyond
Not sure about the exact threotical value but for Nokia it is as high as 200 users per sector, so 600 users in overall cell.